Catalyst composition for catalytic conversion of waste plastic oil, preparation method and application thereof, and method for producing low-carbon olefin by catalytic cracking of waste plastic oil

Abstract

The invention relates to the technical field of catalytic conversion of waste plastic oil, and discloses a catalyst composition for catalytic conversion of waste plastic oil, a preparation method and application thereof, and a method for producing low-carbon olefin by catalytic cracking of waste plastic oil. Based on the dry basis weight of the catalyst composition, the catalyst composition is prepared from the following components in percentage by weight: 41 to 60 percent of meso-macroporous pseudo-boehmite, 10 to 30 percent of clay, 10 to 40 percent of binder and 2 to 10 percent of molecular sieve, wherein the meso-macroporous pseudo-boehmite is metered by aluminum oxide; the total pore volume of the catalyst composition is not less than 0.48 mL / g; the total pore volume of the mesopore and macropore pseudo-boehmite is 0.5 to 2.5 mL / g; the pore volume of pores with the pore diameter of 10-100nm in the mesopore and macropore pseudo-boehmite accounts for more than 50% of the total pore volume. The catalyst composition has the capability of capturing impurity silicon species in waste plastic oil, and the conversion rate of raw materials and the yield of target product low-carbon olefin are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic conversion of waste plastic oil, in particular to a catalyst composition for catalytic conversion of waste plastic oil and a preparation method and application thereof, and a method for producing low-carbon olefins by catalytic cracking of waste plastic oil. BACKGROUND

[0002] Waste plastic recycling includes energy recycling, mechanical recycling and chemical recycling, among which waste plastic chemical recycling is considered as a sustainable waste plastic recycling method, which not only solves the problem of environmental pollution, but also saves energy consumption. Waste plastic cracking is a relatively mature method of waste plastic chemical recycling, that is, through thermal cracking, complex plastic macromolecules are converted into small molecule products (usually gas or liquid) mainly composed of hydrocarbons, which can be further produced into petrochemical products.

[0003] Patent application CN101284235A discloses a preparation method of a catalyst for catalytic cracking of mixed waste plastic to produce fuel, which relates to a two-stage catalyst for catalytic thermal cracking and thermal cracking catalytic upgrading for producing fuel from waste plastic. The first stage catalyst is composed of 2.0wt%-30.0wt% metal oxides and 70.0wt%-98.0wt% white clay or montmorillonite; the second stage is composed 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 sieve, which performs secondary catalytic cracking and isomerization, aromatization and upgrading reactions on the cracked gas of the first stage, thereby improving the ratio of cracked diesel oil fraction.(Shanghai Jiaotong University)

[0004] Patent application CN113398982A discloses a catalyst for catalytic cracking of waste plastic to produce low-carbon olefins, which includes a silicon-aluminum matrix and a molecular sieve. The silicon-aluminum matrix includes a silicon-containing substance and an aluminum-containing substance, and the molecular sieve includes ZSM5 molecular sieve or / and ZSM11 molecular sieve. The catalyst is applied to catalytic cracking of waste plastic to produce low-carbon olefins, which improves the yield of low-carbon olefins and improves the quality of gasoline. The waste plastic in this patent is composed of PE:PP:PS=5:3:2.(Huicheng)

[0005] Patent application CN113398979A discloses a catalyst for catalytic cracking of waste polypropylene plastic to produce fuel, which includes a silicon dioxide matrix and a molecular sieve. The molecular sieve includes one or more of Y-type, beta molecular sieve, USY molecular sieve, SBA 15 and MCM 41. The catalyst is used for catalytic cracking of waste polypropylene plastic, and the total oil yield of gasoline and diesel can reach more than 90%. In this patent, polypropylene particles are selected as the raw material for catalytic cracking.(Huicheng)

[0006] However, in reality, waste plastics are of various types and from various sources, and it is difficult to separate the various components in mixed waste plastics by simple and low-cost means due to the similar apparent physical properties of various common plastics, which makes the waste plastic oil obtained by cracking of waste plastics have problems such as unstable composition and high impurity content.

[0007] It is considered by SINOPEC Research Institute of Petroleum Processing (SRI) that the hydrocarbon composition of waste plastic oil is similar to that of petroleum distillate, and it is theoretically feasible to use waste plastic oil as a raw material for catalytic cracking process, but the high content of silicon and chlorine in waste plastic oil will have certain impact on the catalytic cracking process. The silicon species in waste plastic oil mainly comes from the thermal cracking products of silicon-containing additives in plastics, and usually exists in the form of alkyl cyclosiloxane, mainly octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane, with Si content of 10-103 μg / g. During the subsequent processing of waste plastic oil, the silicon species mainly deposits on the surface of the catalyst, affecting the activity of the catalyst. (Li Mingfeng, Chemical Recycling and Chemical Recycling Technology of Waste Plastics in SINOPEC, China Plastics, 2021)

[0008] Therefore, in the technical route of catalytic conversion of waste plastic oil to produce low-carbon olefins or oil products, the influence of impurity silicon in waste plastic oil cannot be ignored. The measures to treat the impurity silicon in waste plastic oil include desiliconization and silicon tolerance. SRI (CN113862018A) developed a new technology for removing organic silicon by dissolving waste plastic in special oil, which can reduce the viscosity of waste plastic and improve the heat transfer efficiency while removing silicon.

[0009] However, there are few reports on catalysts that can improve product yield and silicon tolerance capacity in the process of catalytic cracking of waste plastic oil to produce low-carbon olefins. SUMMARY

[0010] The purpose of the present application is to overcome the problem that the product yield and the silicon tolerance capacity of the catalyst cannot be compatible in the production of low-carbon olefins by catalytic conversion of waste plastic oil, and to provide a catalyst composition for catalytic conversion of waste plastic oil, which has the ability to capture impurity silicon species in waste plastic oil, and can improve the conversion rate of the raw material and the yield of the target product low-carbon olefins.

[0011] To achieve the above-mentioned purpose, the first aspect of the present application provides a catalyst composition for catalytic conversion of waste plastic oil, wherein, based on the dry weight of the catalyst composition, the catalyst composition comprises the following components: 41-60 wt% of mesoporous pseudoboehmite calculated as alumina, 10-30 wt% of clay, 10-40 wt% of binder and 2-10 wt% of molecular sieve; the total pore volume of the catalyst composition is not less than 0.48 mL / g;

[0012] The total pore volume of the meso-macroporous pseudo-boehmite is 0.5-2.5 mL / g; and the pore volume of the pores with a pore size of 10-100 nm in the meso-macroporous pseudo-boehmite accounts for more than 50% of the total pore volume.

[0013] Preferably, the pore volume of the pores with a pore size of 10-100 nm in the meso-macroporous pseudo-boehmite accounts for more than 80% of the total pore volume, and more preferably 85-95%.

[0014] The second aspect of the present application provides a preparation method of the catalyst composition for catalytic conversion of waste plastic oil according to the first aspect, wherein the method comprises the following steps:

[0015] (1) mixing the meso-macroporous pseudo-boehmite, clay and water, and then adjusting the pH to 2-4 to obtain a first slurry;

[0016] (2) mixing the binder with the first slurry to obtain a second slurry;

[0017] (3) mixing the molecular sieve with the second slurry to obtain a third slurry, and then spray drying and calcining the third slurry.

[0018] The third aspect of the present application provides an application of the composition for catalytic conversion of waste plastic oil according to the first aspect in a catalytic conversion reaction of waste plastic oil.

[0019] The fourth aspect of the present application provides a method for producing low-carbon olefins by catalytic cracking of waste plastic oil, wherein the method comprises the following steps:

[0020] The waste plastic oil is subjected to a cracking reaction in the presence of a catalyst to obtain low-carbon olefins, and the catalyst is the composition for catalytic conversion of waste plastic oil according to the first aspect;

[0021] The content of silicon in the waste plastic oil is 1-1000 mg / kg, and preferably 100-800 mg / kg.

[0022] The catalyst composition for catalytic conversion of waste plastic oil provided by the present application selects a meso-macroporous pseudo-boehmite with a meso-macroporous structure as one of the raw materials, and cooperates with other components with specific contents and compositions to make the catalyst composition have a specific total pore volume. In the preferred case, the catalyst composition for catalytic conversion of waste plastic oil also contains abundant meso-macroporous structures, which can be better applied to the catalytic conversion reaction of waste plastic oil, efficiently capture and accommodate organic silicon species in the waste plastic oil, reduce the damage of silicon species to the active centers of the catalyst molecular sieve, and improve the conversion rate of the raw materials. Further, the catalyst composition contains molecular sieves and other components in the present application, which cooperate with each other to improve the yield of the product low-carbon olefins.

[0023] The method for producing low-carbon olefins by catalytic cracking of waste plastic oil provided by the present invention uses the catalyst composition for catalytic conversion of waste plastic oil provided by the present invention, which can improve the ability to capture silicon species impurities in waste plastic oil during the catalytic cracking process, and at the same time improve the conversion rate of raw materials and the yield of low-carbon olefins from waste plastic oil, and has good prospects for industrial application.

[0024] The method for producing low-carbon olefins by catalytic cracking of waste plastic oil provided by the present invention is preferably applicable to the catalytic cracking of waste plastic oil with a high silicon content (100-800 mg / kg), thereby improving the conversion rate of raw materials and the yield of the target product, low-carbon olefins. Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] The first aspect of this invention provides a catalyst composition for the catalytic conversion of waste plastic oil, wherein, based on the dry weight of the catalyst composition, the catalyst composition comprises the following components: 41-60 wt% of mesoporous boehmite (calculated as alumina), 10-30 wt% of clay, 10-40 wt% of binder, and 2-10 wt% of molecular sieve; the total pore volume of the catalyst composition is not less than 0.48 mL / g;

[0027] The total pore volume of the mesoporous pseudoboehmite is 0.5-2.5 mL / g; the pore volume of the mesoporous pseudoboehmite with a pore size of 10-100 nm accounts for more than 50% of the total pore volume.

[0028] The catalyst composition for the catalytic conversion of waste plastic oil provided by this invention uses boehmite with a mesoporous and macroporous structure as one of the raw materials, which is combined with other components of the present invention in specific amounts and compositions. This results in a specific total pore volume in the catalyst composition. Preferably, the catalyst composition for the catalytic conversion of waste plastic oil also contains abundant mesoporous and macroporous structures, which can be better suited for the catalytic conversion reaction of waste plastic oil, efficiently capturing and accommodating organosilicon species in waste plastic oil, reducing the damage of silicon species to the active centers of the catalyst molecular sieve, and improving the conversion rate of raw materials. Furthermore, the presence of molecular sieves in this catalyst composition, combined with other components in the catalyst composition for the catalytic conversion of waste plastic oil of this invention, can improve the yield of the target product, low-carbon olefins.

[0029] In the present application, the total pore volume of the meso-macroporous pseudoboehmite is determined by the low-temperature static nitrogen adsorption capacity method.

[0030] In the present application, the pore distribution of the meso-macroporous pseudoboehmite is determined by the SH / 0572 (ASTM D 4641) standard, and the BJH adsorption branch is used to calculate the pore volume of the 10-100 nm pore part of the sample.

[0031] In the present application, the total pore volume of the catalyst composition is determined by the water drop method (NB / SH / T 0955-2017).

[0032] In the present application, by further controlling the content of each component in the catalyst composition, the silicon capacity of the catalyst composition for catalytic conversion of waste plastic oil is improved, and the conversion rate of raw materials and the yield of target product low-carbon olefins are improved. Preferably, based on the dry weight of the catalyst composition, the catalyst composition comprises the following components: 45-60 wt% of meso-macroporous pseudoboehmite calculated as alumina, 10-20 wt% of clay, 10-30 wt% of binder and 5-10 wt% of molecular sieve.

[0033] In the present application, the content of the binder, the molecular sieve and the clay is based on the dry basis.

[0034] In the present application, the content of each component in the catalyst composition refers to the weight percentage of the dry basis content of each component to the dry basis content of the catalyst composition.

[0035] In the present application, the dry weight of each component in the catalyst composition refers to the content of the remaining part after each component is calcined at 600℃ for 2h.

[0036] In the present application, the content of each component in the catalyst composition is calculated according to the feeding amount.

[0037] In the present application, preferably, the total pore volume of the catalyst composition is 0.55-0.65 mL / g. The advantage of using this preferred embodiment is that the catalyst composition has a larger pore volume, which provides sufficient space for the silicon capture capacity, and improves the conversion rate of raw materials and the yield of target products.

[0038] In the present application, preferably, the specific surface area of the catalyst composition is 100-300 m 2 / g, and further preferably 195-260 m 2 / g.

[0039] In the present application, the specific surface area of the catalyst composition is determined by the low-temperature nitrogen adsorption method.

[0040] In the present application, preferably, the pore volume of the pores with a pore size of 10-100 nm in the catalyst composition accounts for more than 50% of the total pore volume, preferably 55-75%, and more preferably 60-75%. The advantage of using this preferred embodiment is that the catalyst composition has a large pore size and abundant meso-macroporous structure, and the catalyst composition has a high silicon capacity, which can improve the raw material conversion rate and the yield of the target product.

[0041] In the present application, the pore distribution of the catalyst composition is in accordance with the SH / 0572 (ASTM D 4641) standard, and the pore volume of the 10-100 nm pore part of the sample is calculated by BJH adsorption branch.

[0042] In the present application, the meso-macroporous pseudoboehmite with a specific total pore volume is selected as one of the raw materials of the catalyst composition, which provides the catalyst composition with a high total pore volume, and improves the silicon capacity of the catalyst composition and the raw material conversion rate and the yield of the target product. Preferably, the total pore volume of the meso-macroporous pseudoboehmite is 0.8-2 mL / g, and preferably 0.95-1.5 mL / g.

[0043] In the present application, the meso-macroporous pseudoboehmite with a specific pore size structure is selected as one of the raw materials of the catalyst composition, so that the catalyst composition has a specific pore structure, and the silicon capacity of the catalyst composition is improved. Preferably, the pore volume of the pores with a pore size of 10-100 nm in the meso-macroporous pseudoboehmite accounts for more than 80% of the total pore volume, and more preferably 85-95%.

[0044] In the present application, preferably, the specific surface area of the meso-macroporous pseudoboehmite is 200-500 m 2 / g, preferably 220-500 m 2 / g, and more preferably 350-450 m 2 / g.

[0045] In the present application, the specific surface area of the meso-macroporous pseudoboehmite is determined by a low-temperature static nitrogen adsorption capacity method.

[0046] In the present application, the source of the meso-macroporous pseudoboehmite is not particularly limited, and it can be prepared by a method commonly defined in the art, such as aluminum salt neutralization method, carbonization method, etc., and preferably aluminum salt neutralization method.

[0047] According to a specific embodiment of the present application, the preparation method of the meso-macroporous pseudoboehmite is prepared by the following steps:

[0048] a. mixing the aluminate solution with the alkaline solution to perform a neutralization reaction to obtain a neutralization slurry;

[0049] b. adjusting the pH of the neutralization slurry to 10.5-12.5.

[0050] c. adjusting the pH of the neutralized slurry and aging;

[0051] d. filtering and washing the aged product to obtain a filter cake;

[0052] e. drying the filter cake.

[0053] In the present application, the type of aluminate solution is not particularly limited. Preferably, in step a, the aluminate solution is selected from at least one of an aluminum sulfate solution, a sodium metaaluminate solution, an aluminum nitrate solution, and an aluminum trichloride solution, and is further preferably an aluminum sulfate solution.

[0054] In the present application, the concentration of the aluminate solution is not particularly limited. Preferably, the concentration of the aluminate solution containing aluminum is 40-150 g / L in terms of aluminum oxide.

[0055] In the present application, the type of basic solution is not particularly limited as long as it can perform a neutralization reaction with the aluminate solution. Preferably, the basic solution is selected from at least one of a sodium hydroxide solution, a sodium carbonate solution, and a sodium metaaluminate solution, and is further preferably a sodium metaaluminate solution.

[0056] In the present application, the concentration of the basic solution is not particularly limited as long as it can be mixed with the aluminate solution to satisfy the pH of the neutralization reaction.

[0057] In the present application, the amount of the aluminate solution and the basic solution is not particularly limited as long as it can satisfy the pH of the neutralization reaction, and can be selected by a person skilled in the art according to actual needs.

[0058] In the present application, the mode of the neutralization reaction is not particularly limited, and can be a batch reaction or a continuous reaction, and is preferably a continuous and parallel neutralization reaction.

[0059] In the present application, the conditions of the neutralization reaction are not particularly limited. Preferably, the conditions of the neutralization reaction include a pH of 8.0-9.5, a temperature of 15-65°C, and a residence time of 5-60 min.

[0060] In the present application, preferably, in step b, the pH of the neutralized slurry is adjusted to 10.5-12.5, and is preferably adjusted to 11-12.5. The pH adjustment of the neutralized slurry is achieved by adding a basic compound solution containing no aluminum after the neutralization reaction, and the basic compound solution containing no aluminum is selected from at least one of a sodium hydroxide solution, a sodium carbonate solution, a sodium bicarbonate solution, and ammonia water, and is preferably a sodium carbonate solution.

[0061] In the present application, the concentration and the amount of the non-aluminum containing alkaline compound solution are not particularly limited, as long as the pH of the neutralized slurry can be adjusted to 10.5-12.5, preferably 11-12.5, which can be adjusted according to the specific requirements by those skilled in the art.

[0062] In the present application, preferably, in step c, the aging conditions include: temperature 50-80℃, time 4-48h.

[0063] In the present application, the filtration method in step d is not particularly limited, for example, conventional filtration and washing methods such as vacuum filtration, plate and frame filtration, etc. can be used, which can be adjusted according to the actual requirements by those skilled in the art.

[0064] In the present application, the drying method in step e is not particularly limited, for example, flash drying, oven drying, spray drying, etc. can be used.

[0065] In the present application, the drying conditions in step e are not particularly limited. Preferably, the drying conditions include: drying temperature 80-150℃.

[0066] In the present application, the type of clay is not particularly limited, and the clay defined conventionally in the art can be applied to the present application. Preferably, the clay is selected from at least one of kaolin, bentonite, montmorillonite, bentonite, meerschaum and diatomite.

[0067] In the present application, the source of clay is not particularly limited, for example, it can be obtained by commercial purchase.

[0068] In the present application, the type of binder is not particularly limited, and the binder defined conventionally in the art can be applied to the present application. Preferably, the binder is selected from at least one of aluminum sol, silica sol and acidified pseudo-boehmite, preferably aluminum sol.

[0069] In the present application, the source of the binder is not particularly limited, for example, it can be obtained by commercial purchase.

[0070] In the present application, preferably, the molecular sieve is selected from at least one of Y-type molecular sieve, ZSM-5 molecular sieve and β molecular sieve, further preferably Y-type molecular sieve. By the mutual cooperation of the molecular sieve and other components in the catalyst composition, the yield of low-carbon olefins is improved.

[0071] In the present application, the type of Y-type molecular sieve is not particularly limited, for example, it can be a modified high-silica Y zeolite or an unmodified Y-type molecular sieve. Preferably, the Y-type molecular sieve is selected from at least one of NaY, HY, REY, REHY, USY and REUSY, and further preferably REUSY. In the present application, the type of rare earth RE is not particularly limited, and the rare earth elements commonly defined in the art can be applied to the present application.

[0072] In the present application, the specific type of ZSM-5 molecular sieve is not particularly limited, for example, it can be a modified or unmodified ZSM-5 molecular sieve, for example, it can be HZSM-5 and / or ZSM-5 containing a modified component.

[0073] In the present application, the type of modified component is not particularly limited. Preferably, the modified component is selected from at least one of P, Fe, Zn, Cu, Mg, Zr, Ti, B and a rare earth element.

[0074] In the present application, the specific type of rare earth element is not particularly limited, for example, it can be La, Ce, Y, etc.

[0075] According to a specific embodiment of the present application, the ZSM-5 molecular sieve is selected from at least one of HZSM-5, ZSM-5 containing phosphorus and / or iron, and ZSM-5 containing phosphorus and / or a rare earth element.

[0076] In the present application, the specific type of β molecular sieve is not particularly limited. Preferably, the β molecular sieve is selected from at least one of a hydrogen type β molecular sieve, a phosphorus modified β molecular sieve and a metal modified β molecular sieve. In the present application, the type of metal in the metal modified β molecular sieve is not particularly limited, and the skilled person can select it according to the actual needs.

[0077] In the present application, the source of the molecular sieve is not particularly limited, for example, it can be obtained by commercial purchase.

[0078] The second aspect of the present application provides a preparation method of the catalyst composition for catalytic conversion of waste plastic oil according to the first aspect, wherein the method comprises the following steps:

[0079] (1) mixing, beating and slurrying the mesoporous pseudoboehmite, clay and water, and adjusting the pH to 2-4 to obtain a first slurry;

[0080] (2) mixing the binder with the first slurry to obtain a second slurry;

[0081] (3) mixing and beating the molecular sieve with the second slurry to obtain a third slurry, and then spray drying and sintering the third slurry.

[0082] The preparation method provided by the present application selects mesoporous pseudoboehmite as one of raw materials for preparing a catalyst composition for catalytic conversion of waste plastic oil, and the mesoporous pseudoboehmite with a special pore structure is combined with molecular sieves, clay and a binder component in the present application to prepare a catalyst composition for catalytic conversion of waste plastic oil with specific component content and pore structure, so that the catalyst composition for catalytic conversion of waste plastic oil has high silicon capacity, and the conversion rate of raw materials and the yield of target products are improved.

[0083] In the present application, the structure characteristics and source of the mesoporous pseudoboehmite in step (1) are not particularly limited, as long as the mesoporous pseudoboehmite described in the first aspect can be applied to the present application.

[0084] In the present application, the types of clay, binder and molecular sieve have been described in the first aspect, and will not be repeated here.

[0085] In the present application, preferably, the pH value is adjusted by using an acid in step (1).

[0086] In the present application, the type of acid is not particularly limited, for example, it can be at least one of hydrochloric acid, sulfuric acid and nitric acid.

[0087] In the present application, the amount of acid is not particularly limited, as long as it can meet the aforementioned pH value, and a person skilled in the art can adjust it according to actual needs.

[0088] In the present application, the amount of each substance in step (1) is not particularly limited, as long as it can meet the solid content requirement of the first slurry. Preferably, in step (1), the solid content of the first slurry is 15-45 wt%, and further preferably 20-40 wt%.

[0089] In the present application, the amount of each substance in step (2) is not particularly limited, as long as it can meet the solid content requirement of the second slurry. Preferably, in step (2), the solid content of the second slurry is 15-45 wt%, and further preferably 20-40 wt%.

[0090] In the present application, the amount of each substance in step (3) is not particularly limited, as long as it can meet the solid content of the first slurry. Preferably, in step (3), the solid content of the third slurry is 15-45 wt%, and further preferably 20-40 wt%.

[0091] In the present application, the mixing in steps (1)-(3) is independently carried out under stirring. The present application does not particularly limit the conditions of stirring, and preferably, in steps (1)-(3), the stirring time is independently not less than 30 min, and further preferably 30-120 min.

[0092] In the present application, the spray drying forming refers to the granulation and drying of the catalyst, and the spray drying forming is a technology known to those skilled in the art, which can be operated according to actual needs by those skilled in the art.

[0093] In the present application, the conditions of the spray drying are not particularly limited. Preferably, in step (3), the conditions of the spray drying include that the spray tail gas temperature is 100-250℃.

[0094] In the present application, the method of the calcination treatment is also known to those skilled in the art, and the present application does not particularly limit the same, for example, the calcination treatment can be performed in a muffle furnace.

[0095] In the present application, the conditions of the calcination treatment are not particularly limited. Preferably, in step (3), the conditions of the calcination include that the temperature is 300-800℃ and the time is 0.5-6h; further preferably, the temperature is 400-650℃ and the time is 1-4h.

[0096] The third aspect of the present application provides an application of the composition for catalytic conversion of waste plastic oil in the present application to a catalytic conversion reaction of waste plastic oil.

[0097] The fourth aspect of the present application provides a method for producing low-carbon olefins by catalytic cracking of waste plastic oil, wherein the method comprises the following steps:

[0098] The waste plastic oil is subjected to a catalytic cracking reaction in the presence of a catalyst, and the catalyst is the composition for catalytic conversion of waste plastic oil in the first aspect of the present application;

[0099] In the waste plastic oil, the content of silicon is 1-1000mg / kg, preferably 100-800mg / kg.

[0100] The method for producing low-carbon olefins by catalytic cracking of waste plastic oil provided in the present application selects a composition for catalytic conversion of waste plastic oil with a specific pore structure and composition, which can efficiently capture and accommodate organic silicon species in the waste plastic oil, reduce the damage of silicon species to the active centers of the catalyst molecular sieve, and improve the conversion rate of the raw material and the yield of the target product low-carbon olefins.

[0101] The method for producing low-carbon olefins by catalytic cracking of waste plastic oil provided in the present application not only can be applied to the catalytic conversion of waste plastic oil with a low silicon content, but also can be applied to the catalytic cracking reaction of waste plastic oil with a high silicon content, and has a high raw material conversion rate and a high yield of the target product low-carbon olefins.

[0102] In the present application, the source of waste plastic oil is not particularly limited, preferably, the waste plastic oil is a liquid product obtained by thermal cracking or catalytic cracking of industrial waste plastics. Generally, the source of waste plastic oil is complex, and the high Si content in the waste plastic oil due to the presence of silicon additives has many adverse effects on the subsequent processing of waste plastic oil. By utilizing waste plastic oil from industrial waste plastics, waste is turned into treasure, providing an important development path for waste resources, and having high industrial promotion value.

[0103] In the present application, preferably, the distillation range of the waste plastic oil is 100-600 DEG C, and further preferably 150-550 DEG C.

[0104] In the present application, preferably, the waste plastic oil contains n-alkanes, cycloalkanes, olefins and aromatic hydrocarbons.

[0105] In the present application, preferably, based on the total weight of the waste plastic oil, the content of n-alkanes in the waste plastic oil is 5-50%, the content of cycloalkanes and olefins is 25-55%, and the content of aromatic hydrocarbons is 5-40%.

[0106] In the present application, the conditions of the catalytic cracking reaction are not particularly limited. Preferably, the conditions of the catalytic cracking reaction include: the reaction temperature is 450-650 DEG C, preferably 480-600 DEG C, and the mass ratio of catalyst to oil is 3-15:1, preferably 5-10:1.

[0107] In the present application, preferably, the method further comprises water vapor aging treatment before the catalytic cracking reaction. The present application does not particularly limit the conditions of the aging treatment, and preferably, the temperature is 700-900 DEG C and the time is 10-20 hours.

[0108] The method for producing low-carbon olefins by catalytic cracking of waste plastic oil provided by the present application can be used for catalytic cracking reaction of waste plastic oil with high silicon content (100-800 mg / kg), and can improve the conversion rate of raw materials and the yield of target products.

[0109] The method for producing low-carbon olefins by catalytic cracking of waste plastic oil provided by the present application can be used for catalytic cracking reaction of waste plastic oil with high silicon content (100-800 mg / kg), and can improve the conversion rate of raw materials and the yield of target products.

[0110] The present application will be described in detail below by way of preparation examples and examples.

[0111] In the following preparation examples and examples, if not otherwise specified, the raw materials are all commercially available.

[0112] Na2CO3: National Pharmaceutical Group.

[0113] Kaolin was produced by Suzhou Kaolin Company, solid content 76 wt.%.

[0114] The alumina content in the aluminum sol was 22 wt.%.

[0115] The solid content of the rare earth ultra-stable Y zeolite REUSY was 82 wt.% and the unit cell constant was The Na2O content was 1.6% and the RE2O3 content was 12.4% by weight percentage.

[0116] The solid content of the conventional pseudoboehmite was 73.8 wt.% and the BET specific surface area was 231 m 2 / g, the pore volume was 0.42 mL / g, and the pore volume of the 10-100 nm pores accounted for 31% of the total pore volume.

[0117] The solid content of the meso-macroporous pseudoboehmite: take the meso-macroporous pseudoboehmite as w1 g, after constant temperature treatment at 800°C for 1 h, cool in the desiccator for 3 h, and weigh as w2 g, the solid content = (w1-w2) / w1*100%.

[0118] Specific surface area and pore volume analysis of meso-macroporous pseudoboehmite: use the ASAP 2405N V1.01 automatic adsorption instrument of Micromeritics Company, USA, low-temperature static nitrogen adsorption capacity method, the sample is vacuum degassed at 1.33x10 -2 Pa, 300°C for 4 h, N2 is used as the adsorption medium, the adsorption-desorption isotherm of the sample is determined at 77.4K, the specific surface area of the sample is calculated according to the BET formula, the volume of N2 adsorbed by the sample at a relative pressure p / p0=0.98 is determined, which is converted into the volume of liquid nitrogen, i.e. the total pore volume. The pore distribution is calculated by the BJH adsorption branch according to the SH / 0572 (ASTM D 4641) standard, and the pore volume of the 10-100 nm pores of the sample is calculated.

[0119] Specific surface area analysis of the catalyst composition: use the ASAP 2405N V1.01 automatic adsorption instrument of Micromeritics Company, USA, low-temperature static nitrogen adsorption capacity method, the sample is vacuum degassed at 1.33x10 -2 Pa, 300°C for 4 h, N2 is used as the adsorption medium, the adsorption-desorption isotherm of the sample is determined at 77.4K, and the specific surface area of the sample is calculated according to the BET formula.

[0120] The total pore volume of the catalyst composition is measured by the water drop method (NB / SH / T 0955-2017).

[0121] The pore distribution of the catalyst composition was measured using the SH / 0572 (ASTM D 4641) standard to calculate the pore volume of the 10-100 nm pore fraction of the sample using BJH adsorption desorption.

[0122] The attrition index of the catalyst composition was measured by the NB / SH / T 0964-2017 method.

[0123] Preparation Examples and Comparative Preparation Examples for illustrating the preparation of meso-macroporous pseudoboehmite

[0124] Preparation Example 1

[0125] 4.5 L of an aluminum sulfate solution with an aluminum oxide concentration of 46.5 g / L and 1.0 L of a sodium metaaluminate solution with an Al2O3 concentration of 220 g / L and a Na2O concentration of 227 g / L were added into a neutralization reactor in parallel flow to perform a neutralization reaction, the temperature was 35°C, the pH was 8.5, and the residence time was 30 min;

[0126] After the neutralization reaction, Na2CO3 solution was added to the slurry to adjust the pH to 11.8, and the temperature was heated to 80°C and kept constant for 20 h. The aged slurry was filtered using a vacuum filter, and deionized water at 90°C was added for washing to obtain a filter cake. The filter cake was spray dried to obtain meso-macroporous pseudoboehmite P1, which had a pseudoboehmite structure, and the physicochemical properties are shown in Table 1.

[0127] Preparation Example 2

[0128] 4.5 L of an aluminum sulfate solution with an aluminum oxide concentration of 46.5 g / L and 1.0 L of a sodium metaaluminate solution with an Al2O3 concentration of 220 g / L and a Na2O concentration of 227 g / L were added into a neutralization reactor in parallel flow to perform a neutralization reaction, the temperature was 60°C, the pH was 8.5, and the residence time was 60 min;

[0129] After the neutralization reaction, Na2CO3 solution was added to the slurry to adjust the pH to 12.0, and the temperature was heated to 60°C and kept constant for 24 h. The aged slurry was filtered using a vacuum filter, and deionized water at 90°C was added for washing to obtain a filter cake. The filter cake was spray dried to obtain meso-macroporous pseudoboehmite P2, which had a pseudoboehmite structure, and the physicochemical properties are shown in Table 1.

[0130] Preparation Example 3

[0131] 4.5 L of an aluminum sulfate solution with an aluminum oxide concentration of 46.5 g / L and 1.0 L of a sodium metaaluminate solution with an Al2O3 concentration of 220 g / L and a Na2O concentration of 227 g / L were added into a neutralization reactor in parallel flow to perform a neutralization reaction, the temperature was 55°C, the pH was 8.5, and the residence time was 30 min;

[0132] The slurry after neutralization reaction is added with Na2CO3 solution, the pH is adjusted to 11.0, heated to 60℃ constant temperature for 12 hours, the slurry after aging is filtered by a vacuum filter, and washed with 90℃ deionized water to obtain a filter cake; the filter cake is spray dried to obtain meso-macroporous pseudoboehmite P3, P3 has a pseudoboehmite structure, and the physicochemical properties are shown in Table 1.

[0133] Preparation Example 4

[0134] 4.5L of aluminum sulfate solution with an aluminum oxide concentration of 46.5g / L and 1.0L of sodium metaaluminate solution with an Al2O3 concentration of 220g / L and a Na2O concentration of 227g / L are added into a neutralization reactor in parallel flow to perform a neutralization reaction, the temperature is 55℃, the pH is 8.5, and the residence time is 30min;

[0135] The slurry after neutralization reaction is added with Na2CO3 solution, the pH is adjusted to 10.5, heated to 60℃ constant temperature for 12 hours, the slurry after aging is filtered by a vacuum filter, and washed with 90℃ deionized water to obtain a filter cake; the filter cake is spray dried to obtain meso-macroporous pseudoboehmite P4, P4 has a pseudoboehmite structure, and the physicochemical properties are shown in Table 1.

[0136] Table 1

[0137] Specific surface area, m 2 / g]] Total pore volume, mL / g 10-100 nm pore volume fraction, % Solid content, % P1 389 0.98 88.2 68.3 P2 396 1.22 92.4 67.8 P3 388 0.80 81.0 67.8 P4 300 0.60 66.0 69.5

[0138] Note: The solid content in Table 1 is in wt.%.

[0139] The examples are used to illustrate the preparation of a catalyst composition for catalytic conversion of waste plastic oil

[0140] Example 1

[0141] (1) 721g of meso-macroporous pseudoboehmite P1 and 197g of kaolin are added into 1712g of water, stirred for 120 minutes, and then the pH of the slurry is adjusted to 3.5 with hydrochloric acid to obtain a first slurry with a solid content of 24.3wt%;

[0142] (2) 1273g of aluminum sol is added into the first slurry, and stirring is continued for 120 minutes to obtain a second slurry with a solid content of 23.6wt%;

[0143] (3) 98g of REUSY molecular sieve is added into the second slurry, and stirring is continued for 120 minutes to obtain a third slurry with a solid content of 25wt%; the third slurry is spray dried and shaped, and then calcined at 550℃ for 2 hours to obtain the catalyst C1 of the application.

[0144] Example 2

[0145] (1) 811 g of water was added with 853 g of mesoporous pseudoboehmite P2 and 224 g of kaolin, after stirring for 120 minutes, the slurry pH was adjusted to 3.0 with hydrochloric acid to obtain a first slurry with a solid content of 39.7 wt.%;

[0146] (2) 909 g of aluminum sol was added to the first slurry, and stirring was continued for 60 minutes to obtain a second slurry with a solid content of 34 wt.%;

[0147] (3) 61 g of REUSY molecular sieve was added to the second slurry, and stirring was continued for 90 minutes to obtain a third slurry with a solid content of 35 wt.%. The third slurry was spray dried and shaped, and then calcined at 500°C for 2 hours to obtain the catalyst C2 of the present application.

[0148] Example 3

[0149] According to the method of Example 1, except that mesoporous pseudoboehmite P3 was used instead of mesoporous pseudoboehmite P1 to obtain the catalyst C3 of the present application.

[0150] Example 4

[0151] (1) 892 g of water was added with 588 g of mesoporous pseudoboehmite P1 and 329 g of kaolin, after stirring for 120 minutes, the slurry pH was adjusted to 3.0 with hydrochloric acid to obtain a first slurry with a solid content of 35.9 wt.%;

[0152] (2) 1500 g of aluminum sol was added to the first slurry, and stirring was continued for 60 minutes to obtain a second slurry with a solid content of 29.6 wt.%;

[0153] (3) 24 g of REUSY molecular sieve was added to the second slurry, and stirring was continued for 90 minutes to obtain a third slurry with a solid content of 30 wt.%. The third slurry was spray dried and shaped, and then calcined at 500°C for 2 hours to obtain the catalyst C4 of the present application.

[0154] Example 5

[0155] According to the method of Example 1, except that the mesoporous pseudoboehmite of Preparation Example 4 was selected instead of the mesoporous pseudoboehmite of Preparation Example 1 to obtain the catalyst C5 of the present application.

[0156] Comparative Example 1

[0157] The comparative catalyst DC1 was prepared according to the method of Example 2 of CN113398982A, and the composition of the obtained comparative catalyst was: ZSM-5 molecular sieve accounted for 40% of the weight of the catalyst, the mass of silicon-containing substances calculated based on SiO2 accounted for 8.5% of the weight of the catalyst, the mass of aluminum-containing substances calculated based on Al2O3 accounted for about 50% of the weight of the catalyst, and the rest was phosphorus pentoxide 1.5%.

[0158] Comparative Example 2

[0159] According to the method of Example 1, except that conventional pseudoboehmite was selected instead of mesoporous pseudoboehmite in Example 1, a comparative catalyst DC2 was obtained.

[0160] Comparative Example 3

[0161] (1) 294 g of mesoporous pseudoboehmite P1 and 197 g of kaolin were added into 2236 g of water, and stirred for 120 minutes, then the slurry pH was adjusted to 3.5 with hydrochloric acid to obtain a first slurry with a solid content of 12.8 wt.%;

[0162] (2) 1273 g of aluminum sol was added into the first slurry, and stirred for 120 minutes to obtain a second slurry with a solid content of 15.8 wt.%;

[0163] (3) 451 g of REUSY molecular sieve was added into the second slurry, and stirred for 120 minutes to obtain a third slurry with a solid content of 22 wt.%, which was spray dried and shaped, and then calcined at 550℃ for 2 hours to obtain a comparative catalyst DC3.

[0164] The composition and property parameters of the catalyst composition for catalytic conversion of waste plastic oil in the examples and comparative examples are shown in Table 2.

[0165] Table 2

[0166]

[0167]

[0168] As can be seen from the above table, the catalyst composition provided by the present application can meet the requirement of an attrition index of <3.0% / h, and meet the industrial demand, and at the same time, the catalyst composition has a high total pore volume and abundant mesoporous and macroporous structure.

[0169] Test Example

[0170] The catalyst composition provided by the above examples and comparative examples was aged at 800℃ for 17 hours in a fixed bed aging device with 100 vol.% steam. Then, it was evaluated in a FFB device, and the properties of the waste plastic oil used for evaluation were as follows: a density of 800 kg / m 3 at 20℃, a Si content of 688 μg·g -1 , a n-alkane content of 26 wt.%, a cycloalkane and total olefin content of 48 wt.%, an aromatic content of 26 wt.%, and a distillation range of 155-550℃. The evaluation conditions were as follows: a reaction temperature of 560℃, and a catalyst / oil mass ratio of 9.0. The evaluation results are shown in Table 3.

[0171] Table 3

[0172]

[0173]

[0174] From the above table, it can be seen that the catalytic conversion catalyst composition prepared by the application is used for catalytic cracking of waste plastic oil to produce low-carbon olefins, realizes catalytic conversion and reuse of waste plastic oil, the reaction raw material waste plastic oil has high conversion rate, and meanwhile, high target product low-carbon olefin yield is obtained.

[0175] The preferred embodiments of the application are described in detail above, but the application is not limited thereto. Within the technical concept of the application, various simple modifications can be made to the technical solutions of the application, including that various technical features are combined in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the application and belong to the protection scope of the application.

Claims

1. A catalyst composition for the catalytic conversion of waste plastic oil, characterized in that, Based on the dry weight of the catalyst composition, the catalyst composition comprises the following components: 41-60 wt% of mesoporous boehmite (calculated as alumina), 10-30 wt% of clay, 10-40 wt% of binder, and 2-10 wt% of molecular sieve; the total pore volume of the catalyst composition is not less than 0.48 mL / g. The total pore volume of the mesoporous pseudoboehmite is 0.5-2.5 mL / g; the pore volume of the mesoporous pseudoboehmite with a pore size of 10-100 nm accounts for more than 50% of the total pore volume.

2. The catalyst composition according to claim 1, wherein, Based on the dry weight of the catalyst composition, the catalyst composition comprises the following components: 45-60 wt% of mesoporous pseudoboehmite based on alumina, 10-20 wt% of clay, 10-30 wt% of binder and 5-10 wt% of molecular sieve. And / or, the total pore volume of the catalyst composition is 0.55-0.65 mL / g; And / or, the specific surface area of ​​the catalyst composition is 100-300 m². 2 / g, preferably 195-260m 2 / g; And / or, in the catalyst composition, the pore volume of pores with a pore size of 10-100 nm accounts for more than 50% of the total pore volume, preferably 55-75%, and more preferably 60-75%.

3. The catalyst composition according to claim 1 or 2, wherein, The total pore volume of the mesoporous pseudoboehmite is 0.8-2 mL / g, preferably 0.95-1.5 mL / g; Preferably, the pore volume of the mesoporous pseudoboehmite with a pore size of 10-100 nm accounts for more than 80% of the total pore volume, and more preferably 85-95%. And / or, the specific surface area of ​​the mesoporous pseudoboehmite is 200-500 m². 2 / g, preferably 220-500m 2 / g, more preferably 350-450m 2 / g.

4. The catalyst composition according to any one of claims 1-3, wherein, The clay is selected from at least one of kaolin, bentonite, montmorillonite, bentonite, sepiolite and diatomite; And / or, the binder is selected from at least one of alumina sol, silica sol and acidified boehmite, preferably alumina sol.

5. The catalyst composition according to any one of claims 1-4, wherein, The molecular sieve is selected from at least one of Y-type molecular sieve, ZSM-5 molecular sieve and β molecular sieve; Preferably, the Y-type molecule is screened from at least one of NaY, HY, REY, REHY, USY, and REUSY; Preferably, the ZSM-5 molecular sieve is HZSM-5 and / or ZSM-5 containing modified components; Preferably, the modifying component is selected from at least one of P, Fe, Zn, Cu, Mg, Zr, Ti, B and rare earth elements; Preferably, the β-molecule sieve is selected from at least one of hydrogen-type β-molecule sieve, phosphorus-modified β-molecule sieve, and metal-modified β-molecule sieve.

6. A method for preparing a catalyst composition for the catalytic conversion of waste plastic oil according to any one of claims 1-5, wherein, The method includes the following steps: (1) Mix medium- and large-pore boehmite, clay and water, and then adjust the pH to 2-4 to obtain the first slurry; (2) Mix the adhesive with the first slurry to obtain the second slurry; (3) Mix the molecular sieve with the second slurry to obtain the third slurry, and then spray dry and calcine the third slurry.

7. The method according to claim 6, wherein, In step (1), the solid content of the first slurry is 15-45% by weight, preferably 20-40% by weight; And / or, in step (2), the solid content of the second slurry is 15-45% by weight, preferably 20-40% by weight; And / or, in step (3), the solid content of the third slurry is 15-45% by weight, preferably 20-40% by weight; And / or, in steps (1)-(3), the mixing is carried out independently under stirring conditions; Preferably, in steps (1) to (3), the stirring time is not less than 30 minutes each, and preferably 30-120 minutes.

8. The method according to claim 6 or 7, wherein, In step (3), the roasting conditions include: a temperature of 300-800℃ and a time of 0.5-6h; Preferably, in step (3), the calcination conditions include: a temperature of 400-650℃ and a time of 1-4h.

9. The application of the composition for catalytic conversion of waste plastic oil according to any one of claims 1-5 in the catalytic conversion of waste plastic oil.

10. A method for catalytic cracking of waste plastic oil to produce low-carbon olefins, wherein, The method includes the following steps: The waste plastic oil undergoes a catalytic cracking reaction in the presence of a catalyst, wherein the catalyst is the composition for catalytic conversion of waste plastic oil as described in any one of claims 1-5. The silicon content in the waste plastic oil is 1-1000 mg / kg, preferably 100-800 mg / kg.

11. The method according to claim 10, wherein, The distillation range of the waste plastic oil is 100-600℃, preferably 150-550℃; Preferably, the waste plastic oil contains n-alkanes, cycloalkanes, alkenes, and aromatics; Preferably, based on the total weight of the waste plastic oil, the waste plastic oil contains 5-50% n-alkanes, 25-55% cycloalkanes and olefins, and 5-40% aromatics.

12. The method according to claim 10 or 11, wherein, The conditions for the catalytic cracking reaction include: a reaction temperature of 450-650℃, preferably 480-600℃, and an agent-to-oil mass ratio of 3-15:1, preferably 5-10:1.

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