Catalyst composition for catalytic cracking of raw oil containing waste plastic oil, preparation method thereof and catalytic cracking method

Abstract

The invention relates to a catalyst composition for catalytic cracking of raw oil containing waste plastic oil, a preparation method of the catalyst composition and a catalytic cracking method. The catalyst composition contains 5-60 wt% of a first catalyst and the balance of a second catalyst, on the basis of the dry basis weight of the first catalyst, the first catalyst contains 60-99 wt% of mesoporous silica, and the pore volume of 4-20 nm pores in the mesoporous silica accounts for 60% or more of the total pore volume; the second catalyst contains a molecular sieve, based on the dry base weight of the second catalyst, the content of the molecular sieve is 20-60wt%, the Y-type molecular sieve accounts for more than 80wt% of the total molecular sieve, and the pore volume of 2-5nm pores in the second catalyst accounts for more than 80wt% of the total pore volume. The catalyst composition disclosed by the invention has the capability of capturing impurity silicon species in the waste plastic oil, and when the catalyst composition is used for catalytic cracking of raw oil containing the waste plastic oil, the yield of converting the waste plastic oil into gasoline can be improved.

Description

Technical Field

[0001] This application relates to the field of waste plastic resource utilization, specifically to a catalyst composition for catalytic cracking of feedstock oil containing waste plastic oil, its preparation method, and the catalytic cracking method thereof. Background Technology

[0002] Conventional methods for disposing of waste plastics include landfill, incineration, and recycling. Statistics show that approximately 79% of waste plastics generated worldwide are landfilled or released into the environment, 12% are incinerated, and only about 9% are recycled. Landfilling occupies large amounts of land resources for extended periods, and toxic and harmful substances from the plastics can leach into and spread from landfill sites. Incineration produces toxic and harmful gases, causing secondary environmental pollution. Recycling can be categorized into energy recovery, mechanical recovery, and chemical recovery. Chemical recycling of waste plastics is considered a sustainable method for recycling waste plastics, not only solving environmental pollution problems and saving energy consumption but also contributing to energy security.

[0003] Currently, waste plastic pyrolysis is a relatively mature chemical recycling method for waste plastics. It involves converting complex large plastic molecules into smaller molecules (usually gases or liquids) primarily composed of hydrocarbons through thermal cracking. These smaller molecules can be used to produce petrochemical products. To improve the yield of high-value products, in addition to thermal cracking, catalytic reforming is also employed. This involves using specific catalysts to achieve the desired product yield through a catalytic cracking process similar to crude oil cracking. The feedstock for catalytic reforming can be waste plastics or waste plastic pyrolysis oil, both of which have significantly different chemical compositions from crude oil. Specifically, crude oil has a more complex structure, while waste plastics, although having larger molecular weights, have a simpler composition. This results in significant differences in the reaction processes between crude oil and waste plastics or waste plastic pyrolysis oil. Directly using crude oil cracking catalysts for waste plastics or waste plastic pyrolysis oil can lead to various problems. The most important problem is that due to the complex composition of waste plastics, with some waste polyethylene plastics sometimes containing as much as 10% chlorine, simply applying crude oil cracking catalysts to waste plastic cracking can result in unstable oil quality, often only suitable for low-grade products such as boiler fuel.

[0004] CN101284235B discloses a method for preparing a catalyst for the catalytic cracking of mixed waste plastics to produce fuel oil, involving a two-stage catalyst for catalytic thermal cracking of waste plastics to produce fuel oil and catalytic reforming of plastic pyrolysis oil. The first stage catalyst consists of 2.0wt%~30.0wt% metal oxides and 70.0wt%~98.0wt% clay or montmorillonite; the second stage consists of iron oxide, molybdenum oxide, zinc oxide, cerium oxide, lanthanum oxide, nickel oxide or copper oxide and ZSM-5, MCM-22, USY, REY, Beta or MOR molecular sieves, which perform secondary catalytic cracking and isomerization, aromatization and reforming reactions on the cracked gas from the first stage, thereby increasing the ratio of cracked gasoline and diesel fractions. This method has low efficiency in removing impurities such as silicon and chlorine from plastics, resulting in high content of impurities such as silicon and chlorine in light oil products, making them unsuitable as normal gasoline and diesel blending components. Furthermore, the gasoline yield is low, and the utilization rate of waste plastics is low.

[0005] CN113398982A discloses a catalyst for the catalytic cracking of waste plastics to produce low-carbon olefins, comprising a silica-alumina matrix and a molecular sieve. The silica-alumina matrix includes silicon-containing and aluminum-containing materials, and the molecular sieve includes ZSM-5 molecular sieve and / or ZSM-11 molecular sieve. This catalyst, applied to the catalytic cracking of waste plastics to produce low-carbon olefins, improves the yield of low-carbon olefins and simultaneously improves the quality of gasoline. However, this method uses direct conversion of waste plastics, resulting in light oil products with high levels of impurities such as silicon and chlorine, making them unsuitable as blending components for normal gasoline and diesel fuels and only suitable for low-grade boiler fuel.

[0006] In reality, waste plastics are diverse in type and origin, and because the apparent physical properties of various common plastics are similar, it is difficult to separate the various components in mixed waste plastics using simple and low-cost methods. This results in waste plastic oil obtained from waste plastic pyrolysis having problems such as unstable composition and high impurity content. The silicon content of impurities in waste plastic oil is typically 10-10... 3 μg / g will affect the performance of the catalyst during subsequent processing.

[0007] Therefore, addressing the impact of silicon impurities in waste plastic oil on the catalytic conversion of waste plastic oil to low-carbon olefins or petroleum products is particularly important. However, research on simultaneously improving product selectivity and reducing the impact of silicon impurities on the catalyst in the catalytic cracking of waste plastic oil to increase gasoline production is scarce. Summary of the Invention

[0008] The purpose of this disclosure is to provide a catalyst composition for catalytic cracking of feedstock oil containing waste plastic oil, a method for preparing the same, and a method for catalytic cracking. The catalyst composition disclosed herein has the ability to capture silicon species, which are impurities in waste plastic oil, and when used in catalytic cracking of feedstock oil containing waste plastic oil, it can improve the yield of feedstock oil converted into gasoline.

[0009] To achieve the above objectives, the first aspect of this disclosure provides a catalyst composition for catalytic cracking of feedstock oil containing waste plastic oil, the catalyst composition containing 5-60% by weight of a first catalyst and the balance being a second catalyst; Based on the dry weight of the first catalyst, the first catalyst contains 60-99% by weight of mesoporous silica, and the pore volume of the mesoporous silica with a pore size of 4-20 nm accounts for more than 60% of the total pore volume. The second catalyst contains molecular sieves, and based on the dry weight of the second catalyst, the content of the molecular sieves is 20-60% by weight, Y-type molecular sieves account for more than 80% by weight of the total weight of the molecular sieves, and the pore volume of pores with a pore size of 2-5 nm in the second catalyst accounts for more than 80% of the total pore volume.

[0010] Optionally, the catalyst composition contains 10-50% by weight of a first catalyst and the balance of a second catalyst.

[0011] Optionally, based on the dry weight of the first catalyst, the first catalyst contains 65-95% by weight of mesoporous silica, 4-20% by weight of silicon-based binder and 5-20% by weight of first clay. In the mesoporous silica, pores with a diameter of 4-20 nm account for 80-95% of the total pore volume.

[0012] Optionally, the silicon-based binder is selected from silica sol and / or water glass; The first clay is selected from one or more of kaolin, luteolin, diatomaceous earth, montmorillonite, bentonite and sepiolite.

[0013] Optionally, based on the dry weight of the second catalyst, the second catalyst contains 30-60% by weight of molecular sieve, 10-40% by weight of aluminum-based binder and 5-60% by weight of second clay. The molecular sieve is a Y-type molecular sieve and a ZSM-5 molecular sieve. The Y-type molecular sieve accounts for 80-95% of the total weight of the molecular sieve, and the pore volume of pores with a pore size of 2-5 nm accounts for 80-95% of the total pore volume.

[0014] Optionally, the aluminum-based binder comprises aluminum sol and / or acidified boehmite; The ZSM-5 molecular sieve is derived from HZSM-5 molecular sieve and / or modified ZSM-5 molecular sieve, wherein the modified ZSM-5 molecular sieve contains one or more of the following modifying elements: phosphorus, iron, rare earth elements, Zn, Cu, Mg, Zr, Ti and B. The Y-type molecular sieve is selected from one or more of NaY-type molecular sieves, HY-type molecular sieves, REY-type molecular sieves, REHY-type molecular sieves, USY-type molecular sieves, and REUSY-type molecular sieves; The second clay is selected from one or more of kaolin, rettoite, diatomaceous earth, montmorillonite, bentonite, and sepiolite.

[0015] A second aspect of this disclosure provides a method for preparing the catalyst composition provided in the first aspect of this disclosure, the method comprising: S1. Mesoporous silica, silicon-based binder, first clay and first solvent are mixed in a first process, and the resulting first slurry is calcined in a first process to obtain a first catalyst; A second mixture of molecular sieve, aluminum-based binder, second clay, and second solvent is carried out, and the resulting second slurry is subjected to a second calcination to obtain a second catalyst; wherein the molecular sieve contains a Y-type molecular sieve. S2. The first catalyst and the second catalyst are mixed in a third way.

[0016] Optionally, in step S1, the temperature of the first mixing is 35-55℃, and the time is 0.5-5.0 h; The weight ratio of the mesoporous silica, the silicon-based binder and the first clay is (65-95):(4-20):(5-20), preferably (70-90):(5-15):(5-15). The solid content of the first slurry is 15-45% by weight, preferably 20-40% by weight.

[0017] Optionally, in step S1, the second mixing temperature is 35-55℃, and the time is 0.5-5.0 h; The weight ratio of the molecular sieve, the aluminum-based binder and the second clay is (30-60):(10-40):(5-60), preferably (35-55):(10-35):(10-55); The solid content of the second slurry is 15-45% by weight, preferably 20-40% by weight.

[0018] Optionally, in step S2, the weight ratio of the first catalyst to the second catalyst is (5-60):(40-95), preferably (10-50):(50-90).

[0019] The third aspect of this disclosure provides a method for catalytic cracking feedstock containing waste plastic oil, the method comprising: contacting the feedstock containing waste plastic oil with a catalyst composition provided in the first aspect of this disclosure to carry out a catalytic cracking reaction.

[0020] Optionally, the waste plastic oil contains 5-50% by weight of n-alkanes, 10-50% by weight of the total content of cycloalkanes and olefins, and 1-1000 mg / kg of silicon. The conditions for the catalytic cracking reaction include: a temperature of 450-600℃ and an agent-to-oil mass ratio of 2-10.

[0021] Optionally, the waste plastic oil is prepared by a method including the following steps: pyrolyzing waste plastics at 200-400°C, separating the products of the pyrolysis reaction, and obtaining the waste plastic oil with a distillation range of 150-520°C.

[0022] Through the above technical solution, the first catalyst component and the second catalyst component in the catalyst composition disclosed herein are used in combination, which can not only capture and contain silicon impurities in waste plastic oil, but also improve the ability of feedstock oil containing waste plastic oil to crack and produce gasoline.

[0023] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Detailed Implementation

[0024] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this disclosure.

[0025] The first aspect of this disclosure provides a catalyst composition for catalytic cracking of feedstock oil containing waste plastic oil, the catalyst composition comprising 5-60% by weight of a first catalyst and the balance being a second catalyst; based on the dry weight of the first catalyst, the first catalyst comprises 60-99% by weight of mesoporous silica, wherein the pore volume of the mesoporous silica with a pore size of 4-20 nm accounts for more than 60% of the total pore volume; the second catalyst comprises molecular sieves, based on the dry weight of the second catalyst, the content of the molecular sieves is 20-60% by weight, Y-type molecular sieves account for more than 80% by weight of the total weight of the molecular sieves, and the pore volume of the second catalyst with a pore size of 2-5 nm accounts for more than 80% of the total pore volume.

[0026] Studies have found that the hydrocarbon composition of waste plastic oil is highly similar to that of petroleum distillate hydrocarbons, making its use as a feedstock for catalytic cracking theoretically feasible. However, the high silicon and chlorine content in waste plastic oil can negatively impact the catalytic cracking process. Silicon species in waste plastic oil primarily originate from the thermal decomposition products of silicon-containing additives in plastics, typically existing as alkylcyclosiloxanes, mainly octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. During subsequent processing of waste plastic oil, these silicon species mainly deposit on the catalyst surface, affecting catalyst activity. The catalyst composition disclosed herein consists of a first catalyst and a second catalyst. The first catalyst is a silicon-rich matrix microsphere with 4-20 nm pores that efficiently capture and accommodate organosilicon species from waste plastic oil, allowing large organosilicon molecules to preferentially deposit on the first catalyst, thereby reducing the impact of silicon species on the catalytic performance of the second catalyst. The second catalyst is a molecular sieve catalyst with a smaller pore size compared to the first catalyst, with a larger proportion of 2-5 nm pores, which improves the selectivity of catalytic cracking of hydrocarbon components from waste plastic oil into gasoline. When the catalyst composition disclosed herein is used for catalytic cracking of feedstock containing waste plastic oil, it can significantly improve the yield of gasoline.

[0027] In one specific embodiment of this disclosure, the catalyst composition contains 10-50% by weight of a first catalyst and the balance being a second catalyst.

[0028] In one specific embodiment of this disclosure, based on the dry weight of the first catalyst, the first catalyst contains 65-95% by weight of mesoporous silica, 4-20% by weight of silicon-based binder and 5-20% by weight of first clay; the pore volume of the mesoporous silica with a pore size of 4-20 nm accounts for 80-95% of the total pore volume.

[0029] According to this disclosure, the silicon-based binder and the first clay are well known to those skilled in the art. In one specific embodiment of this disclosure, the silicon-based binder may be selected from, but is not limited to, silica sol and / or water glass, preferably silica sol; the first clay may be selected from, but is not limited to, one or more of kaolin, rettoitite, diatomaceous earth, montmorillonite, bentonite and sepiolite.

[0030] In one specific embodiment of this disclosure, based on the dry weight of the second catalyst, the second catalyst contains 30-60% by weight of molecular sieve, 10-40% by weight of aluminum-based binder, and 5-60% by weight of second clay; the molecular sieve is a Y-type molecular sieve and a ZSM-5 molecular sieve, the Y-type molecular sieve accounts for 80-95% by weight of the total weight of the molecular sieve, and the pore volume of pores with a pore size of 2-5 nm in the second catalyst accounts for 80-95% of the total pore volume.

[0031] According to this disclosure, aluminum-based binders, ZSM-5 molecular sieves, and Y-type molecular sieves are well known to those skilled in the art. In one specific embodiment of this disclosure, the aluminum-based binder includes aluminum sol and / or acidified pseudoboehmite; the ZSM-5 molecular sieve is selected from HZSM-5 molecular sieve, and / or modified ZSM-5 molecular sieve, wherein the modified ZSM-5 molecular sieve contains one or more modifying elements selected from phosphorus, iron, rare earth elements, Zn, Cu, Mg, Zr, Ti, and B. Specifically, the ZSM-5 molecular sieve may be selected from, but is not limited to, ZRP-1 molecular sieve and ZSP-3 molecular sieve. The Y-type molecular sieve is selected from one or more of NaY-type molecular sieves, HY-type molecular sieves, REY-type molecular sieves, REHY-type molecular sieves, USY-type molecular sieves, and REUSY-type molecular sieves. Specifically, the Y-type molecular sieve can be a conventional Y-type molecular sieve, such as one with a silicon-to-aluminum molar ratio (SiO2 / Al2O3) of 5, or a super-stable Y-type molecular sieve. The super-stable Y-type molecular sieve is, for example, a gas-phase super-stable, hydrothermal super-stable, liquid-phase super-stable molecular sieve or a combination thereof. The Y-type molecular sieve may also contain one or more of P and RE (rare earth elements). In one embodiment, the Y-type molecular sieve may be selected from, but is not limited to, DASY molecular sieves, HSY molecular sieves, and SOY molecular sieves. The second clay is selected from one or more of kaolin, rettoitite, diatomaceous earth, montmorillonite, bentonite, and sepiolite.

[0032] The second aspect of this disclosure provides a method for preparing the catalyst composition of the first aspect of this disclosure, the method comprising: S1, firstly mixing mesoporous silica, a silicon-based binder, a first clay, and a first solvent, and firstly calcining the resulting first slurry to obtain a first catalyst; secondly mixing a molecular sieve, an aluminum-based binder, a second clay, and a second solvent, and secondly calcining the resulting second slurry to obtain a second catalyst, wherein the molecular sieve contains a Y-type molecular sieve; S2, thirdly mixing the first catalyst and the second catalyst.

[0033] In one specific embodiment of this disclosure, in step S1, the temperature of the first mixing is 35-55℃, and the time is 0.5-5.0 h; preferably, the temperature is 35-50℃, and the time is 1.0-4.0 h. In this disclosure, the first mixing can be mixing and stirring, and the time of the first mixing refers to the mixing and stirring time. The weight ratio of the mesoporous silica, the silicon-based binder, and the first clay is (65-95):(4-20):(5-20), preferably (70-90):(5-15):(5-15); the solid content of the first slurry is 15-45% by weight, preferably 20-40% by weight.

[0034] In one specific embodiment of this disclosure, in step S1, the second mixing temperature is 35-55℃ and the time is 0.5-5.0 h; preferably, the temperature is 35-50℃ and the time is 1.0-4.0 h. In this disclosure, the second mixing can be mixing and stirring, and the second mixing time refers to the mixing and stirring time. The weight ratio of the molecular sieve, the aluminum-based binder, and the second clay is (30-60):(10-40):(5-60), preferably (35-55):(10-35):(10-55); the solid content of the second slurry is 15-45% by weight, preferably 20-40% by weight.

[0035] In a preferred embodiment, step S1 includes: mixing the molecular sieve, the second clay, and the second solvent, followed by adding an aluminum-based binder for a second mixing. The catalyst composition prepared by this method exhibits superior catalytic performance.

[0036] According to this disclosure, the first solvent and the second solvent can be those well known to those skilled in the art, such as deionized water.

[0037] In one specific embodiment of this disclosure, in step S2, the weight ratio of the first catalyst to the second catalyst is (5-60):(40-95), preferably (10-50):(50-90).

[0038] According to this disclosure, step S1 further includes: sequentially drying and shaping the obtained first slurry and then subjecting it to a first calcination. The drying and shaping can be a method well known to those skilled in the art, such as spray drying, in one embodiment where the exhaust gas temperature of the spray dryer is 100-250°C.

[0039] According to this disclosure, the calcination process can be carried out in apparatus well known to those skilled in the art, such as a muffle furnace or a tube furnace. In one specific embodiment, the calcination conditions include: a temperature of 350-800°C and a time of 0.5-6 hours; preferably, a temperature of 400-650°C and a time of 1-4 hours. Calcination can be carried out in an air atmosphere or an inert atmosphere, wherein the inert atmosphere contains an inert gas, such as nitrogen, helium, or argon.

[0040] The third aspect of this disclosure provides a method for catalytic cracking feedstock containing waste plastic oil, the method comprising: contacting the feedstock containing waste plastic oil with a catalyst composition provided in the first aspect of this disclosure to carry out a catalytic cracking reaction.

[0041] The method disclosed herein uses a catalyst composition as a catalyst, which can effectively increase gasoline production from catalytic cracking of feedstock containing waste plastic oil.

[0042] In this disclosure, the feedstock oil containing waste plastic oil is obtained by mixing one or more of heavy oil, hydrogenated residue oil, vacuum gas oil, atmospheric residue oil, and vacuum residue oil with waste plastic oil. The content of waste plastic oil in the feedstock oil containing waste plastic oil can vary within a wide range, for example, it can be 5-15% by weight.

[0043] According to this disclosure, the waste plastic oil raw material is a liquid product obtained from industrial waste plastics through thermal cracking or catalytic cracking. In one embodiment, the waste plastic oil contains 5-50% by weight of n-alkanes, 10-50% by weight of the total content of cycloalkanes and olefins, and 1-1000 mg / kg of silicon. In a specific embodiment of this disclosure, the waste plastic oil is prepared by a method comprising the following steps: subjecting waste plastics to a cracking reaction at 200-400°C, separating the products of the cracking reaction, and obtaining the waste plastic oil with a distillation range of 150-520°C.

[0044] In one specific embodiment of this disclosure, the conditions for the catalytic cracking reaction include: a temperature of 450-600℃ and a catalyst-to-oil mass ratio of 2-10; preferably, the temperature is 450-550℃ and the catalyst-to-oil mass ratio is 2-9. Under these conditions, the effect of catalytic cracking of feedstock containing waste plastic oil in increasing gasoline production can be further improved.

[0045] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited thereto.

[0046] Unless otherwise stated, all raw materials used in the following examples and comparative examples were commercially available.

[0047] Kaolin produced by Suzhou Kaolin Company, with a solid content of 76% by weight.

[0048] The solid content of mesoporous silica is 75% by weight, and the BET specific surface area is 206 μm. 2 / g, pore volume 0.85mL / g, and pores with a diameter of 4-20 nm account for 80% of the total pore volume.

[0049] The aluminum sol contains 22% aluminum oxide by weight.

[0050] The silica sol contains 30% silica by weight.

[0051] DASY molecular sieve (92.0% by weight solids), ZRP-1 molecular sieve (97.8% by weight solids), and REHY molecular sieve (88.0% by weight solids) were all produced by Sinopec Catalyst Qilu Branch.

[0052] Specific surface area and pore volume analysis: A Micromeritics ASAP 2405N V1.01 automated adsorption analyzer was used, employing the low-temperature static nitrogen adsorption capacity method. The sample surface area was 1.33 × 10⁻⁶. -2 The sample was degassed under vacuum at 300℃ for 4 hours using N2 as the adsorption medium, and the adsorption-desorption isotherm was measured at 77.4 K. The volume of N2 adsorbed by the sample at a relative pressure p / p0 = 0.98 was measured and converted to liquid nitrogen volume, i.e., the total pore volume. The pore distribution was determined according to SH / 0572 (ASTM D 4641) standard, and the pore volume of pores with a pore size of 2-5 nm was calculated using the BJH adsorption method.

[0053] Example 1 S1. 34 parts by weight of mesoporous silica, 24 parts by weight of kaolin, 42 parts by weight of silica sol and deionized water are mixed and stirred at 25°C for 3.0 h. The solid content of the first slurry is 35% by weight. The slurry is then spray-dried and calcined at 550°C for 2 hours to obtain the first catalyst A1.

[0054] 35 parts by weight of DASY molecular sieve, 4 parts by weight of ZRP-1 molecular sieve, 28 parts by weight of kaolin, 33 parts by weight of alumina sol and deionized water were mixed and stirred for 2.0 h to obtain a second slurry with a solid content of 25% by weight. The slurry was then spray-dried and calcined at 500°C for 1 hour to obtain the second catalyst B1.

[0055] S2. The first catalyst A1 and the second catalyst B1 are mixed evenly at a mass ratio of 15:85 to obtain the catalyst composition C1 disclosed herein. Its composition parameters are shown in Table 2, and the same applies below.

[0056] Example 2 S1. Mix 45 parts by weight of mesoporous silica, 25 parts by weight of kaolin, 30 parts by weight of silica sol and deionized water and stir for 3.0 h. The solid content of the resulting first slurry is 35% by weight. Then, spray dry the resulting slurry and calcine it at 550°C for 2 hours to obtain the first catalyst A2.

[0057] 50 parts by weight of DASY molecular sieve, 5 parts by weight of ZRP-1 molecular sieve, 20 parts by weight of kaolin, 25 parts by weight of alumina sol and deionized water were mixed and stirred for 2.0 h. The resulting second slurry had a solid content of 25% by weight. It was then spray-dried and calcined at 500℃ for 1 hour to obtain the second catalyst B2.

[0058] S2. The first catalyst A2 and the second catalyst B2 are mixed evenly at a mass ratio of 10:90 to obtain the catalyst composition C2 disclosed herein.

[0059] Example 3 S1. Mix 50 parts by weight of mesoporous silica, 20 parts by weight of kaolin, 30 parts by weight of silica sol and deionized water and stir for 3.0 h. The solid content of the resulting first slurry is 35% by weight. Then, spray dry the resulting slurry and calcine it at 550°C for 2 hours to obtain the first catalyst A3.

[0060] 42 parts by weight of REHY molecular sieve, 28 parts by weight of kaolin, 30 parts by weight of aluminum sol and deionized water were mixed and stirred for 2.0 h to obtain a second slurry with a solid content of 25% by weight. The slurry was then spray-dried and calcined at 500°C for 1 hour to obtain the second catalyst B3.

[0061] S2. The first catalyst A3 and the second catalyst B3 are mixed evenly at a mass ratio of 25:75 to obtain the catalyst composition C3 disclosed herein.

[0062] Example 4 S1. Mix 55 parts by weight of mesoporous silica, 22 parts by weight of kaolin, 23 parts by weight of silica sol and deionized water and stir for 3.0 h. The solid content of the resulting first slurry is 35% by weight. Then, spray dry the resulting slurry and calcine it at 550°C for 2 hours to obtain the first catalyst A4.

[0063] 42 parts by weight of DASY molecular sieve, 3 parts by weight of ZRP-1 molecular sieve, 40 parts by weight of kaolin, 15 parts by weight of alumina sol and deionized water were mixed and stirred for 2.0 h to obtain a second slurry with a solid content of 25% by weight. The slurry was then spray-dried and calcined at 500℃ for 1 hour to obtain the second catalyst B4.

[0064] S2. The first catalyst A4 and the second catalyst B4 are mixed evenly at a mass ratio of 10:90 to obtain the catalyst composition C4 disclosed herein.

[0065] Example 5 S1. Mix 32 parts by weight of mesoporous silica, 40 parts by weight of kaolin, 28 parts by weight of silica sol and deionized water and stir for 3.0 h. The solid content of the resulting first slurry is 35% by weight. Then, spray dry the resulting slurry and calcine it at 550°C for 2 hours to obtain the first catalyst A5.

[0066] 45 parts by weight of DASY molecular sieve, 35 parts by weight of kaolin, 20 parts by weight of aluminum sol and deionized water were mixed and stirred for 2.0 h to obtain a second slurry with a solid content of 25% by weight. The slurry was then spray-dried and calcined at 500°C for 1 hour to obtain the second catalyst B5.

[0067] S2. The first catalyst A5 and the second catalyst B5 are mixed evenly at a mass ratio of 10:90 to obtain the catalyst composition C5 disclosed herein.

[0068] Example 6 The catalyst composition was prepared using the same method as in Example 1, except that in step S2, the first catalyst A1 and the second catalyst B1 were mixed uniformly at a mass ratio of 5:95 to obtain the catalyst composition C6 disclosed herein.

[0069] Example 7 The catalyst composition was prepared using the same method as in Example 1, except that in step S1, the pore size of the mesoporous silica was 4-20 nm and the pore volume accounted for 65% of the total pore volume.

[0070] Example 8 The catalyst composition was prepared using the same method as in Example 1, except that in step S1, 17.5 parts by weight of DASY molecular sieve, 7.5 parts by weight of ZRP-1 molecular sieve, 50 parts by weight of kaolin, 25 parts by weight of alumina sol and deionized water were mixed and stirred at 25°C for 2.0 h. The resulting second slurry had a solid content of 25% by weight. It was then spray-dried and calcined at 500°C for 1 hour to obtain the second catalyst B8.

[0071] Comparative Example 1 (1) Add 10wt% pseudoboehmite powder (calculated as alumina) to a 30wt% sodium hydroxide solution, control the reaction temperature at 100℃, and react for 5h. The ratio of Al2O3 / Na2O is 0.13, and is denoted as solution A. (2) Add water glass with a concentration of 250 g / L (calculated as SiO2) to solution A, control the temperature at 40℃, and react for 15 h. The SiO2 / Al2O3 = 0.30 is recorded as solution B. (3) Add 1 mol / L ammonium dihydrogen phosphate solution dropwise to solution B, control pH = 9.75, temperature 20℃, and allow to stand for 0.5 h to obtain precipitate; (4) The precipitate was washed and filtered with chemical water to obtain a silica-alumina matrix, which was then slurried with chemical water and denoted as slurry C. (5) Add ZSM-5 molecular sieve dry powder and Y molecular sieve dry powder to slurry C and stir evenly. This is called slurry D. The ratio of the total mass of ZSM-5 molecular sieve dry powder and Y molecular sieve dry powder to the dry mass of the silica-alumina matrix obtained in step (4) is 4:6. (6) Spray dry the slurry D at 260°C and record it as catalyst CB1 for the catalytic cracking of waste plastics to produce low carbon olefins.

[0072] The composition of the obtained comparative catalyst was: 35 parts by weight of Y-type molecular sieve, 4 parts by weight of ZSM-5 molecular sieve, 45.75 parts by weight of silica, and 15.25 parts by weight of alumina. The Y-type molecular sieve accounted for 89.7% of the total molecular sieve weight in the catalyst, and the pore volume of 2-5 nm pores accounted for 65% of the total pore volume.

[0073] Test case The catalyst compositions C1-C8 prepared in Examples 1-8 were aged at 800°C with 100% steam for 17 hours in a fixed-bed aging unit. Then, the ability to produce gasoline via catalytic cracking using heavy oil blended with 10% by weight of waste plastic oil as feedstock was evaluated in an FFB unit. The waste plastic oil was obtained by cracking waste plastics at 400°C, separating the products of the cracking reaction, and obtaining waste plastic oil with a distillation range of 150-520°C.

[0074] The properties of heavy oil are shown in Table 1. Properties of waste plastic oil: density at 20℃ is 852.8 kg / m³. 3 H content 12.0 wt%, Si content 200 μg•g -1 The catalyst contained 36% by weight of n-alkanes, 50% by weight of cycloalkanes and alkenes, and 13% by weight of aromatics. The reaction temperature was 520℃, and the catalyst-to-oil mass ratio was 6.0. To test the catalyst's anti-silicon properties, the evaluation results were the product distribution after 20 reaction cycles, as shown in Table 3. The deposited silicon content refers to the difference between the silicon content on the catalyst after the reaction and the silicon content on the catalyst before the reaction. The deposited silicon content was determined by cyclically cycling the catalyst 20 times and calculating the average difference in silicon content before and after the reaction. The silicon content of the catalyst before and after the reaction was measured by ICP. The mixed feedstock conversion rate refers to the total conversion rate of heavy oil blended with 10% by weight of waste plastic oil.

[0075] In Table 3, the conversion rate = dry gas yield + liquefied petroleum gas yield + gasoline yield + coke yield

[0076] As can be seen from the above, the catalyst composition disclosed herein, when used in the catalytic conversion reaction of waste plastic oil, can significantly increase the yield of gasoline in the conversion reaction products.

[0077] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0079] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A catalyst composition for catalytically cracking a feedstock oil containing waste plastic oil, the catalyst composition containing 5-60 wt% of a first catalyst and a balance of a second catalyst; the first catalyst containing 60-99 wt% of mesoporous silica based on the dry basis weight of the first catalyst, the mesoporous silica having a pore volume of pores with a pore size of 4-20 nm accounting for more than 60% of the total pore volume; the second catalyst containing a molecular sieve, the content of the molecular sieve being 20-60 wt% based on the dry basis weight of the second catalyst, Y-type molecular sieve accounting for more than 80 wt% of the total weight of the molecular sieve, the second catalyst having a pore volume of pores with a pore size of 2-5 nm accounting for more than 80% of the total pore volume.

2. The catalyst composition of claim 1, wherein, the catalyst composition containing 10-50 wt% of the first catalyst and a balance of the second catalyst.

3. The catalyst composition of claim 1, wherein, the first catalyst containing 65-95 wt% of mesoporous silica, 4-20 wt% of a silica-based binder and 5-20 wt% of a first clay based on the dry basis weight of the first catalyst; the mesoporous silica having a pore volume of pores with a pore size of 4-20 nm accounting for 80-95% of the total pore volume.

4. The catalyst composition of claim 3, wherein, the silica-based binder being selected from silica sol and / or water glass; the first clay being selected from one or more of kaolin, rectorite, diatomite, montmorillonite, bentonite and sepiolite.

5. The catalyst composition of claim 1, wherein, the second catalyst containing 30-60 wt% of a molecular sieve, 10-40 wt% of an aluminum-based binder and 5-60 wt% of a second clay based on the dry basis weight of the second catalyst; the molecular sieve being Y-type molecular sieve and ZSM-5 molecular sieve, the Y-type molecular sieve accounting for 80-95 wt% of the total weight of the molecular sieve, the pore volume of pores with a pore size of 2-5 nm accounting for 80-95% of the total pore volume.

6. The catalyst composition of claim 5, wherein, the aluminum-based binder including aluminum sol and / or acidified pseudo-boehmite; the ZSM-5 molecular sieve being selected from HZSM-5 molecular sieve and / or modified ZSM-5 molecular sieve containing one or more modifying elements of phosphorus, iron, rare earth elements, Zn, Cu, Mg, Zr, Ti and B; the Y-type molecular sieve being selected from one or more of NaY-type molecular sieve, HY-type molecular sieve, REY-type molecular sieve, REHY-type molecular sieve, USY-type molecular sieve and REUSY-type molecular sieve; the second clay being selected from one or more of kaolin, rectorite, diatomite, montmorillonite, bentonite and sepiolite. 7.A method for preparing the catalyst composition of any one of claims 1-6, the method comprising: S1,mixing mesoporous silica, a silica-based binder, a first clay and a first solvent to obtain a first slurry, and calcining the first slurry to obtain a first catalyst; mixing a molecular sieve, an aluminum-based binder, a second clay and a second solvent to obtain a second slurry, and calcining the second slurry to obtain a second catalyst; wherein the molecular sieve contains Y-type molecular sieve; S2,mixing the first catalyst and the second catalyst.

8. The method of claim 7, wherein, The temperature of the first mixing in step S1 is 35-55℃, and the time is 0.5-5.0 h; The weight ratio of the mesoporous silica, the silicon-based binder and the first clay is (65-95):(4-20):(5-20), preferably (70-90):(5-15):(5-15); The solid content of the first slurry is 15-45 wt%, preferably 20-40 wt%.

9. The method of claim 7, wherein, The temperature of the second mixing in step S1 is 35-55℃, and the time is 0.5-5.0 h; The weight ratio of the molecular sieve, the aluminum-based binder and the second clay is (30-60):(10-40):(5-60), preferably (35-55):(10-35):(10-55); The solid content of the second slurry is 15-45 wt%, preferably 20-40 wt%.

10. The method of claim 7, wherein, The weight ratio of the first catalyst and the second catalyst in step S2 is (5-60):(40-95), preferably (10-50):(50-90).

11. A process for catalytically cracking a feed oil containing waste plastic oil, the process comprising: The raw oil containing waste plastic oil is contacted with the catalyst composition of any one of claims 1-6 to perform catalytic cracking reaction.

12. The method of claim 11, wherein, The content of n-alkanes in the waste plastic oil is 5-50 wt%, the total content of cycloalkanes and olefins is 10-50 wt%, and the content of silicon is 1-1000 mg / kg; The conditions of the catalytic cracking reaction include: temperature is 450-600℃, and the mass ratio of catalyst to oil is 2-10.

13. The method of claim 11, wherein, The waste plastic oil is prepared by a method comprising the following steps: performing cracking reaction on waste plastic at 200-400℃, and separating the product of the cracking reaction to obtain the waste plastic oil with a distillation range of 150-520℃. The temperature of the first mixing in step S1 is 35-55℃, and the time is 0.5-5.0 h; The weight ratio of the mesoporous silica, the silicon-based binder and the first clay is (65-95):(4-20):(5-20), preferably (70-90):(5-15):(5-15); The solid content of the first slurry is 15-45 wt%, preferably 20-40 wt%. The temperature of the second mixing in step S1 is 35-55℃, and the time is 0.5-5.0 h; The weight ratio of the molecular sieve, the aluminum-based binder and the second clay is (30-60):(10-40):(5-60), preferably (35-55):(10-35):(10-55); The solid content of the second slurry is 15-45 wt%, preferably 20-40 wt%. The weight ratio of the first catalyst and the second catalyst in step S2 is (5-60):(40-95), preferably (10-50):(50-90). The raw oil containing waste plastic oil is contacted with the catalyst composition of any one of claims 1-6 to perform catalytic cracking reaction. The content of n-alkanes in the waste plastic oil is 5-50 wt%, the total content of cycloalkanes and olefins is 10-50 wt%, and the content of silicon is 1-1000 mg / kg; The conditions of the catalytic cracking reaction include: temperature is 450-600℃, and the mass ratio of catalyst to oil is 2-10. The waste plastic oil is prepared by a method comprising the following steps: performing cracking reaction on waste plastic at 200-400℃, and separating the product of the cracking reaction to obtain the waste plastic oil with a distillation range of 150-520℃.

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