A method for producing steam cracking raw materials from waste plastics

Abstract

The present invention relates to a method for producing steam cracking raw materials from waste plastics, the method comprising: sending waste plastic liquefied oil and a hydrogenation catalyst into a mixed feed tank for mixing to obtain a premixed slurry; wherein the waste plastic liquefied oil is obtained by liquefying solid waste plastics with or without adding solvent oil; sending the premixed slurry and hydrogen into a slurry bed reactor for catalytic hydrocracking reaction to obtain a reacted material; separating the reacted material to obtain a gas phase material, a distillate oil material and a catalyst-containing tail oil; optionally, returning at least a portion of the catalyst-containing tail oil as a circulating tail oil to the mixed feed tank for mixing. The method of the present invention can increase the content of saturated hydrocarbons in the reacted material and the product stability, while improving the reaction effect of the catalytic hydrocracking reaction and increasing the yield of the liquid phase product.

Description

Technical Field

[0001] The invention relates to the field of petrochemical industry, and in particular to a method for producing steam cracking raw materials from waste plastics. Background Art

[0002] Plastics have become a basic product that guarantees modern quality of life standards. Polyolefins, such as high-density polyethylene (HDPE), low-density polyethylene (LDPE) and polypropylene (PP) are the most common plastics, accounting for about half of the total production. Existing methods for the treatment of waste plastics include landfill, incineration, direct reuse, plastic recycling, chemical methods, energy recovery, etc. The chemical conversion of waste plastics is considered to be the only process that can achieve sustainable development. Compared with physical recycling, chemical recycling converts waste plastics into cracking furnace feedstock to replace naphtha or natural gas.

[0003] Common chemical recycling methods for waste plastics, such as pyrolysis technology, can convert them into liquid fuels, thereby effectively increasing their added value. Traditional pyrolysis is a free radical random cleavage mechanism, which breaks the CC bond in the waste plastic by heating, accompanied by the cleavage of the CH bond. The resulting free radicals continue to generate a mixture of different small molecule hydrocarbons through various combination reactions.

[0004] Patent 201310540462.8 discloses a method for producing clean fuel oil using waste plastics and high aromatic components. After the high aromatic components are mixed with the waste plastic oil, they first pass through a thermal cracking reaction zone, which uses a combination of gradual temperature increase and constant temperature operation; the cracked gas then enters the catalytic reaction zone, contacts with the catalyst therein to undergo a catalytic reaction, and the resulting reaction effluent is subjected to gas-liquid separation to obtain gas products and liquid oil products.

[0005] Patent 20061006266.0 introduces a catalyst that can be used to crack polyethylene and polypropylene waste plastics to produce fuel oil. It is prepared by modifying KDC-1 molecular sieve and kaolin with phosphoric acid. It is used for cracking waste plastics to reduce the cracking temperature, polyethylene by about 100°C, polypropylene by about 50°C, and the yield of gasoline and diesel is increased, and the amount of residue is reduced.

[0006] However, experiments have found that the existing methods for converting waste plastics have the problem of low content of paraffins and high content of olefins and aromatics in the products. Summary of the invention

[0007] The purpose of the present invention is to provide a method for producing steam cracking raw materials from waste plastics to solve the problem of low alkane content and high olefin and aromatic content in the products in the prior art.

[0008] In order to achieve the above-mentioned purpose, the present invention provides a method for producing steam cracking raw materials from waste plastics, which comprises: feeding waste plastic liquefied oil and a hydrogenation catalyst into a mixed feed tank for mixing to obtain a premixed slurry; wherein the waste plastic liquefied oil is obtained by liquefying solid waste plastics with or without adding solvent oil; feeding the premixed slurry and hydrogen into a slurry bed reactor for catalytic hydrogenation cracking reaction to obtain a reacted material; the hydrogenation catalyst comprises an oil-soluble catalyst and / or a carbon carrier catalyst; separating the reacted material to obtain a gas phase material, a distillate oil material and a catalyst-containing tail oil; optionally, returning at least a portion of the catalyst-containing tail oil as a circulating tail oil to the mixed feed tank for mixing.

[0009] Optionally, the oil-soluble catalyst is composed of a complex formed by an active metal central atom or central ion and an organic ligand bonded by a coordination bond, wherein the organic ligand comprises a hydrocarbon group portion and a coordinating group portion, wherein the coordinating group is a -C(=O)-O group, and forms a coordination bond with the metal central atom or central ion through an oxygen atom; the active metal central atom or central ion in the oil-soluble catalyst is selected from one or more of VB group metals, VIB group metals, VIII group metals and IB group metals having hydrogenation properties.

[0010] Optionally, the active metal central atom or central ion in the oil-soluble catalyst is selected from one or more of Mo, W, Ni, Co, and Fe; based on the total weight of the oil-soluble catalyst and calculated as metal, the content of the active metal central atom or central ion is 2-40 weight %.

[0011] Optionally, the carbon-supported catalyst comprises a carbon-based carrier and an active metal component, the carbon-based carrier comprises one or more of carbon black, activated carbon, blue carbon, graphite and petroleum coke; the active metal element in the active metal component is selected from one or more of Fe, Co and Ni; the active metal element in the carbon-supported catalyst exists in the form of metal oxide; the metal oxide comprises at least one of Fe3O4, Fe2O3, CoO and NiO; the particle size of the active metal component in the carbon-supported catalyst is 5-40nm.

[0012] Optionally, based on the total weight of the carbon support catalyst, the content of the active metal element is 1-50 wt %.

[0013] Optionally, the solid waste plastic is selected from polyolefin waste plastics obtained by polymerization of chain olefin monomers, preferably polyethylene and / or polypropylene; the solvent oil is selected from one or more of light cycle oil, catalytic cracking slurry, furfural extracted oil, propane heavy deoiling, C8-C12 olefins and oil products produced when waste plastics produce steam cracking raw materials, preferably light cycle oil and / or catalytic cracking slurry.

[0014] Optionally, the premixed slurry further contains a promoter; the promoter is selected from sulfur-containing compounds, preferably at least one of sublimated sulfur, carbon disulfide and dimethyl sulfide.

[0015] Optionally, the operating conditions of the mixed feed tank include: temperature of 100-250°C, time of 1-60min; relative to 1g of the solid waste plastic, in terms of metal, the amount of the hydrogenation catalyst added is 100-20000 μg, and the amount of the solvent oil added is 0.05-5g.

[0016] Optionally, the reaction conditions of the catalytic hydrocracking reaction include: reaction temperature of 350-460°C, preferably 370-440°C; reaction pressure of 3-30MPa, preferably 5-25MPa; reaction time of 0.5-10h, preferably 1-6h; relative to 1m 3 The premixed slurry, the amount of hydrogen added is 100-2000Nm 3 , preferably 300-1500Nm 3 .

[0017] Optionally, 90-100 wt % of the catalyst-containing tail oil is returned to the mixed feed tank as circulating tail oil for mixing.

[0018] Through the above technical scheme, the present invention allows waste plastic liquefied oil, hydrogenation catalyst and hydrogen to undergo catalytic hydrogenation cracking reaction in a slurry bed reactor, which can timely close the active free radicals generated in the pyrolysis process of the waste plastic and saturate the olefins, thereby increasing the content of saturated hydrocarbons in the material after the reaction and the stability of the product; at the same time, the present invention uses a liquid catalyst, which is beneficial for the waste plastic to be heated to a molten state in the catalytic hydrogenation reaction unit, so that the catalyst can be better evenly dispersed in the liquid plastic and can better contact and react, thereby improving the reaction effect of the catalytic hydrogenation cracking reaction and increasing the yield of the liquid phase product.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 The present invention is a schematic diagram of a system for producing steam cracking raw materials from waste plastics.

[0022] Description of Reference Numerals

[0023] 1. Preheating furnace; 2. Mixing feed tank; 3. Hydrogen preheating furnace; 4. Slurry bed reactor; 5. Hot high separator; 6. Cold high separator; 7. Cold low separator; 8. Hydrogen separator; 9. Vacuum distillation tower; 10. Solvent oil; 11. Waste plastics; 12. Hydrogenation catalyst; 13. Circulating tail oil; 14. Premixed slurry; 15. Hydrogen; 16. Reacted materials; 17. Gas phase materials; 18. Distillate oil materials; 19. Catalyst-containing tail oil; 20. External tail oil; 21. Light oil; 22. AGO; 23. VGO; 24. External exhaust phase. DETAILED DESCRIPTION

[0024] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0025] The present invention provides a method for producing steam cracking raw materials from waste plastics, which comprises: sending waste plastic liquefied oil and a hydrogenation catalyst into a mixed feed tank for mixing to obtain a premixed slurry; wherein the waste plastic liquefied oil is obtained by liquefying solid waste plastics with or without adding solvent oil; sending the premixed slurry and hydrogen into a slurry bed reactor for catalytic hydrogenation cracking reaction to obtain a reacted material; the hydrogenation catalyst comprises an oil-soluble catalyst and / or a carbon carrier catalyst; separating the reacted material to obtain a gas phase material, a distillate oil material and a catalyst-containing tail oil; optionally, returning at least a portion of the catalyst-containing tail oil as a circulating tail oil to the mixed feed tank for mixing.

[0026] Through the above technical scheme, the present invention allows waste plastic liquefied oil, hydrogenation catalyst and hydrogen to undergo catalytic hydrogenation cracking reaction in a slurry bed reactor, which can timely close the active free radicals generated in the pyrolysis process of the waste plastic and saturate the olefins, thereby increasing the content of saturated hydrocarbons in the material after the reaction and the stability of the product; at the same time, the present invention uses a liquid catalyst, which is beneficial for the waste plastic to be heated to a molten state in the catalytic hydrogenation reaction unit, so that the catalyst can be better evenly dispersed in the liquid plastic and can better contact and react, thereby improving the reaction effect of the catalytic hydrogenation cracking reaction and increasing the yield of the liquid phase product.

[0027] The hydrogenation catalyst used in the present invention is a liquid hydrogenation catalyst, which is prepared by mixing the hydrogenation catalyst with solvent oil or by mixing the hydrogenation catalyst, waste plastics and solvent oil.

[0028] The oil-soluble catalyst is composed of a complex formed by a central active metal atom or central ion and an organic ligand bonded by a coordination bond, wherein the organic ligand comprises a hydrocarbon group and a coordination group, wherein the coordination group is a -C(=O)-O group, and forms a coordination bond with the central metal atom or central ion through an oxygen atom.

[0029] Wherein, the general formula of the oil-soluble catalyst is:

[0030] MO a [R(COO) x ] b ,

[0031] Wherein M represents an active metal, wherein M includes M1 and M2, and M1 and M2 are different from each other; R(COO)x represents an organic ligand, R represents a hydrocarbon group in the organic ligand, COO represents a coordinating group in the organic ligand, and x represents the number of coordinating groups in the organic ligand; a represents the molar ratio of non-coordinating bonded oxygen atoms connected to the metal M to the metal M; b represents the molar ratio of the organic ligand to the metal M; wherein: R is a C3-C19 hydrocarbon group, preferably selected from C5-C11 normal alkyl, C5-C11 isomeric alkyl, C5-C12 cycloalkyl, C6-C12 aromatic or a combination thereof; x is 1, 2 or 3, preferably 1 or 2; a is 0-3, preferably a positive number of 1-3; and b is a positive number of 1-6, preferably a positive number of 2-5.

[0032] Among them, the active metal central atom or central ion in the oil-soluble catalyst is selected from one or more of VB group metals, VIB group metals, VIII group metals and IB group metals with hydrogenation performance; for example, the active metal central atom or central ion can be selected from one or more of Mo, W, Ni, Co, Fe, preferably one or more of Mo, Ni, Co and Fe.

[0033] In one embodiment, the preparation method of the oil-soluble catalyst comprises: reacting a VB group metal, a VIB group metal, a VIII group metal, an IB group metal, an oxide, a hydroxide and / or a metal inorganic salt thereof with hydrogenation performance with an organic ligand compound, wherein the organic ligand compound is selected from an organic carboxylic acid of C4-C20. The reaction temperature of the reaction is 100-350° C., preferably 160-280° C., and the reaction time is 1-8 hours, preferably 2-6 hours.

[0034] Wherein, the carbon carrier catalyst comprises a carbon-based carrier and an active metal component.

[0035] The carbon carrier catalyst is obtained by precipitation reaction between a carbon-based carrier and an active metal component. The specific surface area of ​​the carbon carrier catalyst is 10-1000m 2 / g, preferably 20-600m 2 / g.

[0036] The carbon-based carrier in the carbon-based catalyst is a conventional choice in the art, and the present invention does not make special requirements. For example, the carbon-based carrier can be one or more of carbon black, activated carbon, blue carbon, graphite and petroleum coke. The particle size of the carbon-based carrier is 10-100 μm, preferably 20-60 μm.

[0037] The active metal element in the active metal component is selected from one or more of Fe, Co and Ni. The active metal element in the carbon support catalyst exists in the form of metal oxide; the metal oxide includes at least one of Fe3O4, Fe2O3, CoO and NiO.

[0038] Wherein, the particle size of the active metal component in the carbon carrier catalyst is 5-40 nm, preferably 8-35 nm.

[0039] In one embodiment, the preparation method of the carbon carrier catalyst includes: (1) preparation of the carrier: drying and dehydrating the carbon-based carrier at 100-130°C and then crushing it into a powder with a particle size of 20-60 μm; (2) mixing the metal source solution and the carrier evenly, adding an alkaline substance during stirring to perform a precipitation reaction; wherein the conditions of the precipitation reaction are: the reaction temperature is 20-100°C, the reaction time is 30-300 min, and the precipitation reaction product obtained after the precipitation reaction is completed is subjected to solid-liquid separation to obtain a solid material; (3) drying the solid material at 90-120°C for 60-360 min, placing it in a tubular furnace, and roasting it at 300-700°C for 90-360 min under inert atmosphere protection, and the obtained roasting product is the carbon carrier catalyst. The stoichiometric ratio of the amount of the alkaline substance to the amount of the active metal in the active metal source solution is (0.8-1.5):1.

[0040] The active metal source solution is selected from one or more of nitrate solution, sulfate solution and chloride solution; the active metal element in the active metal source solution is selected from one or more of Fe, Co and Ni. The alkaline substance is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and ammonia solution. The inert atmosphere is selected from one or more of nitrogen, argon and helium.

[0041] In order to reduce the production cost while ensuring the performance of the hydrogenation catalyst, the content of active metals in the hydrogenation catalyst can be limited; for example, in a specific embodiment of the present invention, based on the total weight of the oil-soluble catalyst and calculated as metal, the content of the active metal central atom or central ion is 2-40% by weight, preferably 10-30% by weight; based on the total weight of the carbon support catalyst, the content of the active metal element is 1-50% by weight, preferably 15-40% by weight.

[0042] In the above embodiment, the use of a hydrogenation catalyst can enhance the reaction activity of the hydrocracking reaction, and the hydrogenation catalyst is dissolved or dispersed in solvent oil. When used in the hydrocracking reaction, the hydrogenation catalyst and the waste plastic can be fully contacted, which can further enhance the reaction activity of the hydrocracking reaction and further enhance the yield of the liquid phase product.

[0043] The method further comprises, before mixing, preheating the solvent oil to 40-180°C, preferably 60-150°C, in a preheating furnace.

[0044] Wherein, the solid waste plastic is selected from polyolefin waste plastics obtained by polymerization of chain olefin monomers, preferably polyethylene and / or polypropylene.

[0045] The solvent oil is selected from one or more of light cycle oil, catalytic cracking slurry, furfural extracted oil, propane heavy deoiling, C8-C12 olefins and the oil products produced when the waste plastics are produced by steam cracking raw materials disclosed in the present invention or other waste plastics, preferably light cycle oil and / or catalytic cracking slurry.

[0046] The operating conditions of the mixed feed tank include: temperature of 100-250°C, preferably 110-230°C, more preferably 120-200°C; time of 1-60min, preferably 10-50min, more preferably 20-40min. In addition, relative to 1g of the solid waste plastic, the amount of the hydrogenation catalyst added is 100-20000μg, preferably 200-10000μg, more preferably 500-5000μg, and the amount of the solvent oil added is 0.05-5g, preferably 0.1-3g, more preferably 0.1-2g.

[0047] In the above-described embodiment, the present invention has no special requirements for the order of mixing the materials. For example, the liquid catalyst and the promoter can be mixed, or the pre-reaction product, the waste plastic and the recycled material can be mixed first and then subjected to the hydrocracking reaction; the waste plastic can be converted into a molten state by a mixing feed tank, and the hydrogenation catalyst and the solvent oil can be mixed into a slurry material, which can further enhance the activity of the reaction.

[0048] The premixed slurry further contains an accelerator; the accelerator is selected from sulfur-containing compounds, preferably at least one of sublimated sulfur, carbon disulfide and dimethyl sulfide.

[0049] The reaction conditions of the catalytic hydrocracking reaction include: a reaction temperature of 350-460°C, preferably 370-440°C, more preferably 380-430°C; a reaction pressure of 3-30MPa, preferably 5-25MPa, more preferably 7-20MPa; a reaction time of 0.5-10h, preferably 1-6h, more preferably 1.5-5h; relative to 1m 3 The premixed slurry, the amount of hydrogen added is 100-2000Nm 3 , preferably 300-1500Nm 3 , further preferably 500-1000Nm 3 .

[0050] Among them, the separation method used for the hydrogenation reaction product in the present invention is a conventional choice in the art, and the present invention does not make special requirements. For example, the separation method can be one or more of a cold high-pressure separation method, a hot high-pressure separation method, a cold low-pressure separation method, and a flash distillation method. In a specific embodiment of the present invention, the hydrogenation reaction product is sent to a hot high-separator and subjected to hot high-pressure separation treatment at 360-430°C and 10-20MPa to obtain a gas phase material and a distillate oil material; then the gas phase material is sent to a cold high-separator and subjected to cold high-pressure separation treatment at 30-60°C and 10-20MPa, and then sent to a cold low-separator and subjected to gas-liquid separation treatment at 30-60°C and 0.1-3MPa to obtain light oil and a mixed gas phase, wherein the light oil is a naphtha fraction.

[0051] The mixed gas phase produced by separation is separated into purified hydrogen and an exhaust gas phase by a hydrogen separator; the purified hydrogen and fresh hydrogen are preheated to 350-450° C. in a hydrogen preheating furnace and then returned to the slurry bed reactor.

[0052] The distillate oil material is sent to a vacuum distillation tower for vacuum distillation to obtain catalyst tail oil, AGO and VGO; the cut point of the AGO and VGO is 330-370°C, and the cut point of the VGO and the catalyst tail oil is 490-510°C. AGO refers to atmospheric gas oil, which refers to the fraction with a boiling range of about 200-400°C obtained by distillation of crude oil, and is a light oil; VGO refers to vacuum gas oil, which refers to the general term for the fraction with a boiling range of about 350-500°C obtained by vacuum distillation of crude oil, and is a heavy oil.

[0053] Among them, the catalyst-containing tail oil can be completely discharged, or part of it can be returned to the mixed feed tank as circulating tail oil for mixing; specifically, if the value of the active metal in the hydrogenation catalyst is high and the amount of the hydrogenation catalyst used is large (such as more than 1000ppm), 90-100% by weight, preferably 94-100% by weight of the catalyst-containing tail oil is returned to the mixed feed tank as circulating tail oil for mixing; if the value of the active metal in the hydrogenation catalyst is low, the value of the active metal in the hydrogenation catalyst is high, but the amount added is relatively small or the tail oil needs to be recovered, the catalyst-containing tail oil is completely discharged to the subsequent device.

[0054] The catalyst-containing tail oil can be separated by solid-liquid separation to separate the catalyst from the liquid phase, and the separated liquid phase can be recycled back to the reactor. The solid-liquid separation can be carried out by one or a combination of separation methods such as sedimentation, centrifugation, filtration, and cyclone separation.

[0055] In one embodiment, the method for producing steam cracking raw materials from waste plastics comprises:

[0056] The solvent oil 10 is heated to 90-110° C. in a preheating furnace 1 and then enters a mixing feed tank 2 to mix with solid waste plastics 11 and a hydrogenation catalyst 12 for 20-40 minutes to obtain a premixed slurry 14;

[0057] The premixed slurry 14, the promoter and the hydrogen 15 are fed into the slurry bed reactor 4 for catalytic hydrocracking reaction to obtain the reacted material 16; wherein, relative to 1m 3 The premixed slurry 14, the amount of hydrogen 15 added is 300-1500Nm 3 ;

[0058] The reacted material 16 is sent to a hot high separation device 5 for hot high pressure separation treatment at 360-430°C and 10-20MPa to obtain a gas phase material 17 and a distillate oil material 18;

[0059] The gaseous material 17 is sent to a cold high-pressure separator 6 for cold high-pressure separation treatment at 30-60°C and 10-20MPa, and then sent to a cold low-pressure separator 7 for gas-liquid separation treatment at 30-60°C and 0.1-3MPa to obtain light oil 21 and a mixed gas phase; the mixed gas phase is separated by a hydrogen separator 8 to obtain purified hydrogen and an exhaust gas phase 24; the purified hydrogen and fresh hydrogen 15 are preheated in a hydrogen preheating furnace 3 and then returned to the slurry bed reactor 4;

[0060] The distillate oil material 18 is sent to the vacuum distillation tower 9 for vacuum distillation to obtain catalyst-containing tail oil 19, AGO 22 and VGO 23; 90-100 weight % of the catalyst-containing tail oil 19 is returned to the mixed feed tank 2 as the circulating tail oil 13, and 0-10 weight % of the catalyst-containing tail oil 19 is discharged from the system as the external tail oil 20.

[0061] The following examples will further illustrate the method provided by the present invention, but are not intended to limit the present invention.

[0062] Preparation Example 1-4

[0063] Preparation Examples 1, 2, and 4 Preparation of Oil-Soluble Catalyst C1((MoNi)O 1.0 (C7H 16 COO 2.67 )、C2(MoO 1.2 (C7H 16 COO 2.8 ) and C4((MoCo)O 1.27 (C7H 16 COO 2.45 ), the specific methods include:

[0064] The reaction raw materials, reaction conditions and test results used in Preparation Examples 1, 2 and 4 are shown in Table 1. Weigh the corresponding weight of the compound as shown in Table 1, place it in a three-necked flask, and then react under the conditions shown in Table 1. After the reaction is completed, the metal compound in the flask of Preparation Examples 1, 2 and 4 is completely dissolved. The liquid reaction product in the flask of Preparation Examples 1, 2 and 4 is poured out to obtain an oil-soluble catalyst. The metal content and elemental composition of the obtained product are measured, and the composition of the product is obtained according to the measured results. Among them, the metal content is measured using a SPECTRO ARCOS SOP plasma emission spectrometer using inductively coupled plasma emission spectrometry (ICP-OES), and the measurement conditions are that the optical chamber is sealed and filled with argon, vertical observation, and the wavelength range is 130-770nm; the elemental composition is measured in the following manner: the content of elements C and H is measured by an Italian Cara Erba EA1110 element analyzer using the SH0656 method; the S element content is measured using the energy dispersive X-ray fluorescence spectrometry GB17040 method; the O element content is measured using the O-content method.

[0065] Table 1

[0066]

[0067] Preparation Example 3 The carbon support catalyst C3 is prepared by the following method:

[0068] (1) Preparation of carrier: The activated carbon was dried and dehydrated at 120°C and then crushed into powder with a particle size of 20-60 μm;

[0069] (2) preparing an aqueous ferric sulfate solution with Fe2(SO4)3 as a metal source solution, wherein the Fe content in the aqueous ferric sulfate solution is 2.4 g relative to 100 mL of the active metal source solution; after uniformly mixing 125 ml of the aqueous ferric sulfate solution with 5 g of the carrier, 20.16 g of a 28 wt% ammonia solution is added during stirring to perform a precipitation reaction; wherein the conditions for the precipitation reaction are: a reaction temperature of 60°C, a reaction time of 60 min, and a precipitation reaction product obtained after washing the precipitate is subjected to solid-liquid separation to obtain a solid material;

[0070] (3) The solid material was dried at 110° C. for 300 min, placed in a tube furnace, and calcined at 490° C. for 300 min under N2 gas protection. The calcined product was the carbon support catalyst C3. The properties of the carbon support catalyst C3 are shown in Table 2.

[0071] Among them, the parameter test of the carbon support catalyst is as follows:

[0072] Metal phase: Characterized on a D8ADVANCE X-ray diffractometer, Cu Kα radiation, λ=0.15418 nm, 2θ scanning range of 5° to 70°, and scanning rate of 4 (°) / min.

[0073] Metal component particle size: calculated using the Scherrer formula based on data measured by an X-ray diffractometer.

[0074] Carbon support catalyst particle size: measured by MS3000 laser particle size analyzer.

[0075] Specific surface area of ​​carbon-supported catalyst: measured by ASAP2460 physical BET adsorption instrument.

[0076] Table 2 Properties of carbon-supported catalyst C3

[0077]

[0078] Example 1

[0079] 10 g of solvent oil 10 is heated to 100° C. in a preheating furnace 1 and then fed into a mixing feed tank 2 and mixed with 90 g of solid waste plastic 11 and a hydrogenation catalyst 12 for 30 minutes to obtain a premixed slurry 14;

[0080] The premixed slurry 14, the promoter and the hydrogen 15 are fed into the slurry bed reactor 4 for catalytic hydrocracking reaction to obtain the reacted material 16; wherein, relative to 1m 3 The premixed slurry 14, the amount of hydrogen 15 added is 1000Nm 3;

[0081] The reacted material 16 is sent to a hot high separation device 5 for hot high pressure separation treatment at 420°C and 19 MPa to obtain a gas phase material 17 and a distillate oil material 18;

[0082] The gaseous material 17 is sent to a cold high-pressure separator 6 for cold high-pressure separation treatment at 40°C and 19MPa, and then sent to a cold low-pressure separator 7 for gas-liquid separation treatment at 40°C and 1MPa to obtain light oil 21 and a mixed gas phase; the mixed gas phase is separated by a hydrogen separator 8 to obtain purified hydrogen and an external exhaust phase 24; the purified hydrogen and fresh hydrogen 15 are preheated in a hydrogen preheating furnace 3 and then returned to the slurry bed reactor 4;

[0083] The distillate oil material 18 is sent to the vacuum distillation tower 9 for vacuum distillation to obtain catalyst tail oil 19, AGO 22 and VGO 23; 99 weight % of the catalyst tail oil 19 is returned to the mixed feed tank 2 as the circulating tail oil 13, and 1 weight % of the catalyst tail oil 19 is discharged from the system as the external tail oil 20. The specific reaction conditions and product properties are shown in Table 3.

[0084] Example 2

[0085] The method for producing steam cracking raw materials from waste plastics is the same as in Example 1, except that the types of waste plastics, types of hydrogenation catalysts and reaction conditions are different. Specific reaction conditions and product properties are shown in Table 3.

[0086] Example 3

[0087] The method for producing steam cracking raw materials from waste plastics is the same as in Example 1, except that the types of waste plastics, types of hydrogenation catalysts and reaction conditions are different. Specific reaction conditions and product properties are shown in Table 3.

[0088] Example 4

[0089] The method for producing steam cracking raw materials from waste plastics is the same as in Example 1, except that the accelerator and reaction conditions are different. The specific reaction conditions and product properties are shown in Table 3.

[0090] Comparative Example 1

[0091] The method for producing steam cracking raw materials from waste plastics is the same as in Example 1, except that the reaction is non-hydrogenated and no hydrogenation catalyst is used. Specific reaction conditions and product properties are shown in Table 3.

[0092] Comparative Example 2

[0093] The method for producing steam cracking raw materials from waste plastics is the same as that of Comparative Example 1, except that the types of waste plastics are different. Specific reaction conditions and product properties are shown in Table 3.

[0094] Comparative Example 3

[0095] 10 g of solvent oil 10 is heated to 100° C. in a preheating furnace 1 and then fed into a mixing feed tank 2 and mixed with 90 g of solid waste plastic 11 and a hydrogenation catalyst 12 for 30 minutes to obtain a premixed slurry 14;

[0096] The premixed slurry 14, the promoter and the hydrogen 15 are fed into a fixed bed reactor for catalytic hydrocracking reaction. The catalyst in the fixed bed is a purchased supported catalyst containing Mo-Ni and an alumina carrier. After the device has been running for a period of time, it becomes clogged and cannot continue to react.

[0097] Table 3 Reaction conditions and product properties of the embodiments and comparative examples

[0098]

[0099]

[0100] Light oil refers to gasoline fraction and diesel fraction.

[0101] Light oil yield: Light oil yield = paraffin content + olefin content + aromatic content;

[0102] Total yield of light oil = yield of light oil at initial boiling point ~ 180°C + yield of light oil at 180 ~ 350°C:

[0103] Light oil composition: For example, paraffins = content of paraffins in the initial boiling point to 180°C + content of paraffins in the temperature range of 180 to 350°C.

[0104] From the results in Table 1, according to Examples 1 to 4 and Comparative Examples 1 to 3, the method provided by the present invention can efficiently convert PP and / or PE waste plastics into light oil, the liquid hydrogenation catalyst has good contact with the waste plastics, can improve the catalytic efficiency of the hydrogenation catalyst and the liquid yield of the hydrocracking reaction, and the product distribution is good, olefins can be effectively saturated, the paraffin content is high, and the obtained product has high added value. In addition, the hydrocracking reaction does not require a fixed bed reactor, and the operation is simple.

[0105] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0106] 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, the present invention will not further describe various possible combinations.

[0107] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for producing steam cracking raw materials from waste plastics, characterized in that: The method includes: The waste plastic liquefied oil and the hydrogenation catalyst are fed into a mixed feed tank for mixing to obtain a premixed slurry; wherein the waste plastic liquefied oil is obtained by liquefying solid waste plastic with or without adding solvent oil; The premixed slurry and hydrogen are fed into a slurry bed reactor for catalytic hydrocracking reaction to obtain a reacted material; the hydrogenation catalyst comprises an oil-soluble catalyst and / or a carbon-supported catalyst; Separating the reacted materials to obtain gas phase materials, distillate oil materials and catalyst-containing tail oil; Optionally, at least a portion of the catalyst-containing tail oil is returned to the mixed feed tank as circulating tail oil for mixing; The oil-soluble catalyst is composed of a complex formed by a central active metal atom or central ion and an organic ligand bonded by a coordination bond, wherein the organic ligand comprises a hydrocarbon group and a coordination group, wherein the coordination group is a -C(=O)-O group and forms a coordination bond with the central metal atom or central ion through an oxygen atom; The active metal central atom or central ion in the oil-soluble catalyst is selected from one or more of VB group metals, VIB group metals, VIII group metals and IB group metals having hydrogenation performance; The carbon-supported catalyst comprises a carbon-based support and an active metal component, wherein the carbon-based support comprises one or more of carbon black, activated carbon, blue carbon, graphite and petroleum coke; the active metal element in the active metal component is selected from one or more of Fe, Co and Ni; The active metal element in the carbon support catalyst exists in the form of metal oxide; the metal oxide includes at least one of Fe3O4, Fe2O3, CoO and NiO; the particle size of the active metal component in the carbon support catalyst is 5-40nm; The reaction conditions of the catalytic hydrocracking reaction include: reaction temperature of 350-460°C, reaction pressure of 3-30MPa, reaction time of 0.5-10h, relative to 1m 3 The premixed slurry, the amount of hydrogen added is 100-2000Nm 3 .

2. The method according to claim 1, characterized in that The active metal central atom or central ion in the oil-soluble catalyst is selected from one or more of Mo, W, Ni, Co, and Fe; Based on the total weight of the oil-soluble catalyst and calculated as metal, the content of the active metal central atom or central ion is 2-40% by weight.

3. The method according to claim 1, characterized in that Based on the total weight of the carbon support catalyst, the content of the active metal element is 1-50 weight %.

4. The method according to claim 1, characterized in that: The solid waste plastic is selected from polyolefin waste plastics obtained by polymerization of chain olefin monomers; The solvent oil is selected from one or more of light cycle oil, catalytic cracking slurry, furfural extracted oil, propane heavy deoiling, C8-C12 olefins and oil products produced when waste plastics produce steam cracking raw materials.

5. The method according to claim 4, characterized in that The solid waste plastic is polyethylene and / or polypropylene.

6. The method according to claim 4, characterized in that The solvent oil is light cycle oil and / or catalytic cracking slurry oil.

7. The method according to claim 1, characterized in that The premixed slurry also contains a promoter; the promoter is selected from sulfur-containing compounds.

8. The method according to claim 7, characterized in that The accelerator is selected from at least one of sublimed sulfur, carbon disulfide and dimethyl sulfide.

9. The method according to claim 1, characterized in that: The operating conditions of the mixed feed tank include: temperature of 100-250° C., time of 1-60 min; relative to 1 g of the solid waste plastic, in terms of metal, the amount of the hydrogenation catalyst added is 100-20000 μg, and the amount of the solvent oil added is 0.05-5 g.

10. The method according to claim 1, characterized in that The reaction conditions of the catalytic hydrocracking reaction include: reaction temperature of 370-440°C; reaction pressure of 5-25MPa; reaction time of 1-6h; relative to 1m 3 The premixed slurry, the amount of hydrogen added is 300-1500Nm 3 .

11. The method according to claim 1, characterized in that 90-100 wt % of the catalyst-containing tail oil is returned to the mixed feed tank as circulating tail oil for mixing.

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