Catalyst for catalytic upgrading of waste plastic pyrolysis volatile matter, preparation method of catalyst and waste plastic pyrolysis oil preparation method

Abstract

The invention provides a catalyst for catalytic upgrading of waste plastic pyrolysis volatile matters, a preparation method of the catalyst and a waste plastic pyrolysis oil preparation method. The preparation method of the catalyst comprises the following steps: mixing nickel nitrate, carbamide and water, and then adding a Y-type molecular sieve to obtain a turbid liquid; and heating and aging the turbid liquid according to a specific procedure, and then carrying out solid-liquid separation, washing, drying and roasting to obtain the catalyst. The method comprises the following steps: filling a reactor with the catalyst, filling a raw material filling container with the waste plastics, placing the raw material filling container above a catalyst filling part in the reactor, and keeping the distance between the top of the catalyst and a gas outlet of the raw material filling container at 60-80mm; charging protective gas into the reactor from the top of the reactor, heating the reactor, pyrolyzing the waste plastics in the raw material filling container to generate volatile matters, and carrying out catalytic cracking on the volatile matters through a catalyst before the volatile matters are condensed into liquid fuel; and cooling and collecting the catalytic cracking product to obtain oil.

Description

Technical Field

[0001] The invention belongs to the technical field of waste plastic pyrolysis, and specifically relates to a catalyst for catalytically improving the quality of waste plastic pyrolysis volatiles and a preparation method thereof, and a method for producing oil from waste plastic pyrolysis. Background Art

[0002] Plastic products play an important role in people's lives due to their excellent durability, corrosion resistance, plasticity and stability, and are widely used in packaging, construction and manufacturing industries. However, with the increase in plastic production and consumption, the amount of waste plastics is increasing, causing environmental pollution. The most effective way to reduce waste plastic pollution is to increase the recycling rate of waste plastics and increase the resource utilization value of waste plastics.

[0003] Among the current methods of resource utilization of waste plastics, waste pyrolysis technology with the goal of high-quality oil and gas products is considered to be one of the most promising technologies for the utilization of waste plastics due to its wide applicability of raw materials, low pollution and low emissions. Waste plastics can be converted into liquid fuels or other high-value-added chemicals through pyrolysis to achieve resource recycling. During the pyrolysis process, the CC bonds and CH bonds in the plastic molecules break to obtain hydrocarbon molecules with different carbon numbers, H2 and solid residues. Studies have found that the factors affecting the pyrolysis of waste plastics mainly include the type of plastic, the form of the reactor, the pyrolysis temperature, pressure and the heating rate. However, in general, the liquid products obtained by pyrolysis of waste plastics alone have poor selectivity, low alkane content, low hydrogen yield, and poor overall oil and gas quality. In order to increase the added value of the oil and gas products of plastic pyrolysis, a certain amount of catalyst is usually added during the plastic pyrolysis process, such as molecular sieve catalysts and transition metal catalysts.

[0004] By mixing waste plastics with catalysts and then catalytically pyrolyzing them, in-situ catalytic modification of waste plastic pyrolysis oil can be achieved, but it often faces the problem of difficult catalyst recovery and inability to reuse. At the same time, the obtained oil products still generally have problems such as poor hydrogen and methane selectivity, low content of medium and light components, and low content of monocyclic aromatic hydrocarbons. Summary of the invention

[0005] The purpose of the present invention is to provide a technical solution that can solve the blockage problem caused by the high content of heavy components in the current catalytic cracking technology of waste plastics, and at the same time can obtain high yields of hydrogen, methane and high-quality oil products (high content of light components and high content of monocyclic aromatic hydrocarbons).

[0006] In order to achieve the above objectives, the present invention provides the following three technical solutions.

[0007] In a first aspect, the present invention provides a method for preparing a catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics, wherein the method comprises:

[0008] Mixing nickel salt, carbonamide and water to obtain a mixed solution, and mixing the mixed solution with a Y-type molecular sieve to obtain a suspension;

[0009] The suspension is heated from room temperature to a first temperature of 60-75°C at a first heating rate of 5-10°C / min and stirred at a constant temperature for 1-2.5 hours, and then heated to a second temperature of 75-85°C at a second heating rate of 1-5°C / min and stirred at a constant temperature for 2-3.5 hours, and the second heating rate is greater than the first heating rate, and the second temperature is greater than the first temperature, and further heated to a third temperature of 88-92°C at a third heating rate of 1-5°C / min and stirred at a constant temperature for 4-8 hours, and then the stirring is stopped and the suspension is aged at 15-30°C for 10-16 hours;

[0010] The product after aging treatment is subjected to solid-liquid separation, washing, drying and roasting to obtain a catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics.

[0011] The technical solution provided by the present invention performs step-by-step and slow precipitation by strictly controlling the temperature rising steps during the precipitation process, and the Ni metal particles on the finally prepared catalyst are small and evenly dispersed, and are suitable for catalytic upgrading of volatiles from pyrolysis of waste plastics. The catalyst used for catalytic upgrading of volatiles from pyrolysis of waste plastics can actually obtain high-yield hydrogen, methane and high-quality oil products (high in light component content and high in monocyclic aromatic hydrocarbon content).

[0012] According to a preferred embodiment of the first aspect, the nickel salt is selected from at least one of nickel nitrate, nickel chloride and nickel oxalate.

[0013] According to a preferred embodiment of the first aspect, the Y-type molecular sieve is HY molecular sieve.

[0014] According to a preferred embodiment of the first aspect, the stirring speed of the constant temperature stirring at the first temperature is greater than the stirring speed of the constant temperature stirring at the second temperature, and the stirring speed of the constant temperature stirring at the second temperature is greater than the stirring speed of the constant temperature stirring at the third temperature;

[0015] Furthermore, the stirring speed of the constant temperature stirring at the first temperature is 70-110 r / m; the stirring speed of the constant temperature stirring at the second temperature is 50-70 r / m; and the stirring speed of the constant temperature stirring at the third temperature is 30-50 r / m.

[0016] According to a preferred embodiment of the first aspect, the suspension is heated from room temperature to a first temperature of 70°C at a first heating rate of 5°C / min and stirred at a constant temperature of 90r / m for 1 hour, then heated to a second temperature of 80°C at a second heating rate of 2°C / min and stirred at a constant temperature of 60r / m for 2 hours, further heated to a third temperature of 90°C at a third heating rate of 2°C / min and stirred at a constant temperature of 40r / m for 4 hours, then the stirring is stopped and the suspension is aged at room temperature for 10 hours.

[0017] According to a preferred embodiment of the first aspect, the method further comprises tableting and sieving the calcined product to a particle size not exceeding 40 mesh; further, the method further comprises tableting and sieving the calcined product to a particle size of 40 mesh-60 mesh.

[0018] According to a preferred embodiment of the first aspect, the mass ratio of nickel in the nickel salt, carbon amide, and Y-type molecular sieve is: 0.1-0.3:0.3-0.9:1.

[0019] According to a preferred embodiment of the first aspect, the mass content of water in the mixed solution is greater than 65%, based on the total mass of the mixed solution being 100%.

[0020] According to a preferred embodiment of the first aspect, the Y-type molecular sieve is pre-treated with steam and acid-washed; further, the Y-type molecular sieve is pre-treated with 650°C steam and acid-washed with 0.8 mol / L nitric acid solution for dealuminization; in a specific embodiment, the Y-type molecular sieve is treated at 650°C for 2 hours under a steam atmosphere, and then further acid-washed with 0.8 mol / L nitric acid solution for dealuminization to obtain the treated Y-type molecular sieve to be mixed with the mixed solution to prepare the suspension.

[0021] In a second aspect, the present invention provides a catalyst for catalytic upgrading of volatile products from pyrolysis of waste plastics prepared by the method for preparing the catalyst for catalytic upgrading of volatile products from pyrolysis of waste plastics provided in the first aspect.

[0022] According to a preferred embodiment of the second aspect, the mass content of Ni in the catalyst is 1.0-20.0wt.%, based on the total mass of the catalyst being 100%;

[0023] Furthermore, the mass content of Ni is 2.0-10.0wt.%.

[0024] In a third aspect, the present invention provides a method for producing oil by pyrolysis of waste plastics, wherein the method comprises:

[0025] The catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics provided by the second aspect of the present invention is loaded in a reactor, the waste plastics are loaded into a raw material loading container and the raw material loading container is placed above the catalyst loading position in the reactor, and the distance between the top of the catalyst and the gas outlet of the raw material loading container is 60-80 mm; protective gas is filled into the reactor from the top of the reactor, and the reactor is heated, the waste plastics in the raw material loading container are pyrolyzed to generate volatiles, and the volatiles are catalytically cracked by the catalyst before being condensed into liquid fuel;

[0026] The catalytic cracking products are cooled and collected to obtain the oil.

[0027] The waste plastic pyrolysis oil production method provided by the present invention adopts the method of placing waste plastic and catalyst in layers to avoid direct contact between plastic (including solid or melted liquid) and catalyst, thereby reducing the risk of catalyst pore blockage and deactivation. The waste plastic placed separately is pyrolyzed to produce volatiles, and the volatiles produced by pyrolysis are catalytically cracked and upgraded by special catalysts to obtain high-yield hydrogen, methane and high-quality oil products (high light component content and high monocyclic aromatic hydrocarbon content); in the process, the distance between the catalyst and the raw material is controlled at a low level to reduce the time for the pyrolysis volatiles to reach the catalyst, thereby reducing the secondary reaction of the pyrolysis volatiles before catalysis, which helps to obtain more oil products.

[0028] According to a preferred embodiment of the third aspect, the catalyst is packed with a thickness of 15-20 mm.

[0029] According to a preferred embodiment of the third aspect, the method further comprises activating the catalyst in a mixed gas flow of H2 and N2 at 450-600°C before use.

[0030] According to a preferred embodiment of the third aspect, the mass ratio of the catalyst to the waste plastic is 0.1-2.0;

[0031] Furthermore, the mass ratio of the catalyst to the waste plastic is 0.25-1.0.

[0032] According to a preferred embodiment of the third aspect, the reactor is heated to 500-600°C.

[0033] According to a preferred embodiment of the third aspect, the heating of the reactor is carried out by using an infrared fast pyrolysis fixed bed.

[0034] According to a preferred embodiment of the third aspect, the heating rate of the reactor is 1-20°C / s;

[0035] Furthermore, the heating rate of the reactor is 15-20°C / s.

[0036] According to a preferred embodiment of the third aspect, the catalytic cracking products are cooled and collected using a cold trap, and the temperature of the cold trap is -25°C to -15°C.

[0037] According to a preferred embodiment of the third aspect, the waste plastics include one or a combination of two or more of polyethylene (PE), polystyrene (PS) and polypropylene (PP).

[0038] According to a preferred embodiment of the third aspect, wherein the reactor is a vertical fixed bed reactor;

[0039] Furthermore, the raw material loading container is a sleeve that can be arranged in a vertical fixed bed reactor.

[0040] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0041] 1. The preparation method of the catalyst for catalytic upgrading of volatile products from pyrolysis of waste plastics provided by the present invention performs step-by-step and slow precipitation by strictly controlling the temperature rising steps during the precipitation process. The Ni metal particles on the finally prepared catalyst are small and evenly dispersed, and the catalyst is suitable for catalytic upgrading of volatile products from pyrolysis of waste plastics. The catalyst can be used for catalytic upgrading of volatile products from pyrolysis of waste plastics to obtain high yields of hydrogen, methane and high-quality oil products (high content of light components and high content of monocyclic aromatic hydrocarbons).

[0042] 2. The waste plastic pyrolysis oil production method provided by the present invention, in the catalytic cracking process of the specific catalyst provided by the present invention, because the catalyst is below the waste plastic bed, the residence time of the waste plastic pyrolysis volatiles on the catalyst bed for catalytic upgrading is increased, so that the pyrolysis volatiles are fully contacted and reacted on the catalyst, and heavy components such as paraffin are cracked and converted into hydrogen, methane and light components. The problem of high content of heavy components in oil products and easy clogging of pipelines in the waste plastic pyrolysis process is effectively solved, and it has important guiding significance for the technical field of catalytic cracking of waste plastics to produce hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the quartz tube reactor used in Examples and Comparative Examples.

[0044] Figure 2 The oil, gas and solid yield distribution diagram of the pyrolysis products of Examples 1-3 and Comparative Examples 1-3.

[0045] Figure 3 The oil fraction content distribution diagram of Examples 1-3 and Comparative Examples 1-3.

[0046] Figure 4 The gas yield distribution diagram of Examples 1-3 and Comparative Examples 1-3.

[0047] Figure 5 The chemical composition of the oil obtained in Comparative Examples 1-3.

[0048] Figure 6 The chemical composition of the oil obtained in Examples 1-3.

[0049] Figure 7 This is a transmission electron microscope image of the catalyst provided in Example 1.

[0050] Figure 8 This is a transmission electron microscope image of the catalyst provided in Example 1.

[0051] Fig. 9 This is a scanning transmission electron micrograph of the catalyst provided in Example 1.

[0052] Fig.10 This is the Ni element distribution image of the catalyst provided in Example 1. DETAILED DESCRIPTION

[0053] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0054] The experimental methods involved in the embodiments of the present invention are conventional methods unless otherwise specified; the designed reagents and materials are all commercially available unless otherwise specified.

[0055] Example 1

[0056] This embodiment provides a catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics, which is prepared by the following preparation method:

[0057] The HY molecular sieve is dealuminated by using 650°C water vapor and 0.8 mol / L nitric acid solution to obtain a Y-type molecular sieve carrier; specifically, the Y molecular sieve is treated at 650°C for 2 hours under a water vapor atmosphere, and then further acid-washed and dealuminated by using 0.8 mol / L nitric acid solution to obtain the treated Y-type molecular sieve for standby use;

[0058] Weigh 2.477 g of nickel nitrate hexahydrate and 1.53 g of carbonamide and dissolve them in 50 mL of deionized water to obtain a mixed solution, and then add 4 g of a Y-type molecular sieve carrier to the mixed solution to prepare a suspension;

[0059] The suspension was heated from 20°C to 70°C at a heating rate of 5°C / min and stirred at a constant temperature of 90r / m for 1 hour, then continued to be heated to 80°C at a heating rate of 2°C / min and stirred at a constant temperature of 60r / m for 2 hours, further continued to be heated to 90°C at a heating rate of 2°C / min and stirred at a constant temperature of 40r / m for 4 hours, then stopped stirring and cooled naturally, and precipitated and aged at room temperature for 10 hours;

[0060] The aged product is filtered, washed, dried and roasted, and is pressed and sieved to 40 meshes 40 meshes-60 meshes to obtain the catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics.

[0061] The transmission electron microscopy image of the catalyst is shown in Figure 7 , Figure 8 As shown, scanning transmission electron microscopy images are Fig. 9 As shown, the Ni element distribution image is as follows Fig.10 shown.

[0062] This embodiment also provides a method for producing oil by pyrolysis of waste plastics, the method comprising:

[0063] The catalyst for catalytic upgrading of volatile products from pyrolysis of waste plastics provided in this embodiment is heated from 20°C to 550°C at a heating rate of 5°C / min in a fixed bed reactor under a mixed atmosphere of hydrogen and nitrogen, and activated at 550°C for 3 hours to obtain an activated catalyst; wherein the hydrogen flow rate in the mixed atmosphere of hydrogen and nitrogen is 80 mL / min, and the nitrogen flow rate is 120 mL / min.

[0064] 1g of activated catalyst was loaded into the middle constant temperature zone of the quartz tube reactor (the top of the quartz tube reactor was provided with a gas inlet and the bottom of the reactor was provided with a product outlet), waste plastics were loaded into the quartz sleeve, and 1g of polyethylene waste plastics was loaded into the quartz sleeve and placed in the quartz tube reactor tube and suspended above the catalyst bed. Figure 1 As shown; the distance between the top of the catalyst and the gas outlet of the raw material filling container is 70mm; wherein, the inner diameter of the quartz tube reactor is 18mm and the length is 300mm, and the inner diameter of the quartz sleeve is 14mm and the length is 60mm;

[0065] The entire quartz tube reactor is placed on an infrared rapid heating fixed bed, nitrogen is introduced into the quartz tube reactor, and the quartz tube reactor is heated from 20°C to 550°C at a heating rate of 20°C / s using the infrared rapid heating fixed bed and kept at a constant temperature for 600s, the waste plastic in the quartz sleeve is pyrolyzed to produce volatiles, and the volatiles are catalytically cracked and upgraded by the catalyst in the quartz tube reactor before being condensed into liquid fuel; wherein, the N2 gas flow rate is 200mL / min;

[0066] The products after catalytic cracking and upgrading are cooled and collected in a cold trap (-25°C) to obtain liquid oil products and gas products.

[0067] The gas products were tested by gas chromatography, and the liquid oil products were tested by simulated distillation. Figure 2-Figure 4 , Figure 6 shown.

[0068] The content of light components of the oil product (light components refer to the part with a boiling point below 350°C) is 87.5wt.%, the content of monocyclic aromatic hydrocarbons is 38.99wt.%, the yield of gas products is 38.5wt.%, and the yields of H2 and CH4 in the gas products are 202mL / g waste plastic and 114mL / g waste plastic respectively. In addition, no obvious residue was found at the outlet of the quartz tube after the reaction.

[0069] Example 2

[0070] This embodiment also provides a method for producing oil by pyrolysis of waste plastics, the method comprising:

[0071] The catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics provided in Example 1 was heated from 20°C to 550°C at a heating rate of 5°C / min in a fixed bed reactor under a mixed atmosphere of hydrogen and nitrogen, and activated at 550°C for 3 hours to obtain an activated catalyst; wherein the hydrogen flow rate in the mixed atmosphere of hydrogen and nitrogen was 80 mL / min, and the nitrogen flow rate was 120 mL / min;

[0072] 1g of activated catalyst was loaded into the middle constant temperature zone of the quartz tube reactor (the top of the quartz tube reactor was provided with a gas inlet and the bottom of the reactor was provided with a product outlet), waste plastics were loaded into the quartz sleeve, and 1g of polystyrene waste plastics were loaded into the quartz sleeve and placed in the quartz tube reactor tube and suspended above the catalyst bed. Figure 1 As shown; the distance between the top of the catalyst and the gas outlet of the raw material filling container is 70mm; wherein, the inner diameter of the quartz tube reactor is 18mm and the length is 300mm, and the inner diameter of the quartz sleeve is 14mm and the length is 60mm;

[0073] The entire quartz tube reactor is placed on an infrared rapid heating fixed bed, nitrogen is introduced into the quartz tube reactor, and the quartz tube reactor is heated from 20°C to 550°C at a heating rate of 20°C / s using the infrared rapid heating fixed bed and kept at a constant temperature for 600s, the waste plastic in the quartz sleeve is pyrolyzed to produce volatiles, and the volatiles are catalytically cracked and upgraded by the catalyst in the quartz tube reactor before being condensed into liquid fuel; wherein, the N2 gas flow rate is 200mL / min;

[0074] The products after catalytic cracking and upgrading are cooled and collected in a cold trap (-25°C) to obtain liquid oil products and gas products.

[0075] The gas products were tested by gas chromatography, and the liquid oil products were tested by simulated distillation. Figure 2-Figure 4 , Figure 6 shown.

[0076] The light component content of the oil product was 80.0wt.%, the monocyclic aromatic hydrocarbon content was 62.21wt.%, the gas product yield was 4.5wt.%, and the yields of H2 and CH4 in the gas product were 108mL / g waste plastic and 25mL / g waste plastic, respectively. In addition, no obvious residue was found at the outlet of the quartz tube after the reaction.

[0077] Example 3

[0078] This embodiment also provides a method for producing oil by pyrolysis of waste plastics, the method comprising:

[0079] The catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics provided in Example 1 is activated at 550° C. for 3 hours in a mixed atmosphere of hydrogen and nitrogen to obtain an activated catalyst;

[0080] 1g of activated catalyst was loaded into the middle constant temperature zone of the quartz tube reactor (the top of the quartz tube reactor was provided with a gas inlet and the bottom of the reactor was provided with a product outlet), waste plastics were loaded into the quartz sleeve, and 1g of polypropylene waste plastics was loaded into the quartz sleeve and placed in the quartz tube reactor tube and suspended above the catalyst bed. Figure 1 As shown; the distance between the top of the catalyst and the gas outlet of the raw material filling container is 70mm; wherein, the inner diameter of the quartz tube reactor is 18mm and the length is 300mm, and the inner diameter of the quartz sleeve is 14mm and the length is 60mm;

[0081] The entire quartz tube reactor is placed on an infrared rapid heating fixed bed, nitrogen is introduced into the quartz tube reactor, and the quartz tube reactor is heated from 20°C to 550°C at a heating rate of 20°C / s using the infrared rapid heating fixed bed and kept at a constant temperature for 600s, the waste plastic in the quartz sleeve is pyrolyzed to produce volatiles, and the volatiles are catalytically cracked and upgraded by the catalyst in the quartz tube reactor before being condensed into liquid fuel; wherein, the N2 gas flow rate is 200mL / min;

[0082] The products after catalytic cracking and upgrading are cooled and collected in a cold trap (-25°C) to obtain liquid oil products and gas products.

[0083] The gas products were tested by gas chromatography, and the liquid oil products were tested by simulated distillation. Figure 2-Figure 4 , Figure 6 shown.

[0084] The light component content of the oil product was 86.5wt.%, the monocyclic aromatic hydrocarbon content was 78.38wt.%, the gas product yield was 41.6wt.%, and the yields of H2 and CH4 in the gas product were 247mL / g waste plastic and 149mL / g waste plastic, respectively. In addition, no obvious residue was found at the outlet of the quartz tube after the reaction.

[0085] Comparative Example 1

[0086] This comparative example also provides a method for producing oil by pyrolysis of waste plastics, the method comprising:

[0087] 1g of quartz sand of the same mesh size is filled into the middle constant temperature zone of the quartz tube reactor (the top of the quartz tube reactor is provided with a gas inlet and the bottom is provided with a product outlet), the waste plastic is filled into the quartz sleeve, and 1g of polyethylene waste plastic is filled into the quartz sleeve and placed in the quartz tube reaction tube and suspended above the catalyst bed. Figure 1 As shown; the distance between the top of the catalyst and the gas outlet of the raw material filling container is 70mm; wherein, the inner diameter of the quartz tube reactor is 18mm and the length is 300mm, and the inner diameter of the quartz sleeve is 14mm and the length is 60mm;

[0088] The entire quartz tube reactor is placed on an infrared rapid heating fixed bed, nitrogen is introduced into the quartz tube reactor, and the quartz tube reactor is heated from 20°C to 550°C at a heating rate of 20°C / s using the infrared rapid heating fixed bed and kept at a constant temperature for 600s, the waste plastic in the quartz sleeve is pyrolyzed to produce volatiles, and the volatiles pass through the quartz sand in the quartz tube reactor before being condensed into liquid fuel; wherein, the N2 gas flow rate is 200mL / min;

[0089] The product after passing through quartz sand is cooled and collected in a cold trap (-25°C) to obtain liquid oil and gas products.

[0090] The gas products were tested by gas chromatography, and the liquid oil products were tested by simulated distillation. Figure 2-Figure 4 , Figure 5 shown.

[0091] The light component content of the oil product is 37.0wt.%, does not contain monocyclic aromatic hydrocarbons, the gas product yield is 2.9wt.%, and the total yield of H2 and CH4 in the gas product is no more than 5mL / g of waste plastic. In addition, obvious paraffin-like white solid matter was found at the bottom of the quartz tube after the reaction.

[0092] Comparative Example 2

[0093] This comparative example also provides a method for producing oil by pyrolysis of waste plastics, the method comprising:

[0094] 1g of quartz sand of the same mesh size is filled into the middle constant temperature zone of the quartz tube reactor (the top of the quartz tube reactor is provided with a gas inlet and the bottom is provided with a product outlet), the waste plastic is filled into the quartz sleeve, and 1g of polystyrene waste plastic is filled into the quartz sleeve and placed in the quartz tube reaction tube and suspended above the catalyst bed. Figure 1 As shown; the distance between the top of the catalyst and the gas outlet of the raw material filling container is 70mm; wherein, the inner diameter of the quartz tube reactor is 18mm and the length is 300mm, and the inner diameter of the quartz sleeve is 14mm and the length is 60mm;

[0095] The entire quartz tube reactor is placed on an infrared rapid heating fixed bed, nitrogen is introduced into the quartz tube reactor, and the quartz tube reactor is heated from 20°C to 550°C at a heating rate of 20°C / s using the infrared rapid heating fixed bed and kept at a constant temperature for 600s, the waste plastic in the quartz sleeve is pyrolyzed to produce volatiles, and the volatiles pass through the quartz sand in the quartz tube reactor before being condensed into liquid fuel; wherein, the N2 gas flow rate is 200mL / min;

[0096] The product after passing through quartz sand is cooled and collected in a cold trap (-25°C) to obtain liquid oil and gas products.

[0097] The gas products were tested by gas chromatography, and the liquid oil products were tested by simulated distillation. Figure 2-Figure 4 , Figure 5 shown.

[0098] The light component content of the oil product was 70.5wt.%, the monocyclic aromatic hydrocarbon content was 32.65wt.%, the gas product yield was 2.3wt.%, and the total yield of H2 and CH4 in the gas product was no more than 5mL / g of waste plastic. In addition, obvious paraffin-like white solid matter was found at the bottom of the quartz tube after the reaction.

[0099] Comparative Example 3

[0100] This comparative example also provides a method for producing oil by pyrolysis of waste plastics, the method comprising:

[0101] 1g of quartz sand of the same mesh size is filled into the middle constant temperature zone of the quartz tube reactor (the top of the quartz tube reactor is provided with a gas inlet and the bottom is provided with a product outlet), the waste plastic is filled into the quartz sleeve, and 1g of polypropylene waste plastic is filled into the quartz sleeve and placed in the quartz tube reaction tube and suspended above the catalyst bed. Figure 1 As shown; the distance between the top of the catalyst and the gas outlet of the raw material filling container is 70mm; wherein, the inner diameter of the quartz tube reactor is 18mm and the length is 300mm, and the inner diameter of the quartz sleeve is 14mm and the length is 60mm;

[0102] The entire quartz tube reactor is placed on an infrared rapid heating fixed bed, nitrogen is introduced into the quartz tube reactor, and the quartz tube reactor is heated from 20°C to 550°C at a heating rate of 20°C / s using the infrared rapid heating fixed bed and kept at a constant temperature for 600s, the waste plastic in the quartz sleeve is pyrolyzed to produce volatiles, and the volatiles pass through the quartz sand in the quartz tube reactor before being condensed into liquid fuel; wherein, the N2 gas flow rate is 200mL / min;

[0103] The product after passing through quartz sand is cooled and collected in a cold trap (-25°C) to obtain liquid oil and gas products.

[0104] The gas products were tested by gas chromatography, and the liquid oil products were tested by simulated distillation. Figure 2-Figure 4 , Figure 5 shown.

[0105] The light component content of the oil product is 47.5wt.%, and it does not contain monocyclic aromatic hydrocarbons. The gas product yield is 3.4wt.%, and the total yield of H2 and CH4 in the gas product is no more than 5mL / g of waste plastic. In addition, obvious paraffin-like white solid matter was found at the bottom of the quartz tube after the reaction.

[0106] Comparative Example 4

[0107] This comparative example provides a catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics, which is prepared by the following preparation method:

[0108] The HY molecular sieve is dealuminated by using 650°C water vapor and 0.8 mol / L nitric acid solution to obtain a Y-type molecular sieve carrier; specifically, the Y molecular sieve is treated at 650°C for 2 hours under a water vapor atmosphere, and then further acid-washed and dealuminated by using 0.8 mol / L nitric acid solution to obtain the treated Y-type molecular sieve for standby use;

[0109] Weigh 2.477 g of nickel nitrate hexahydrate and 1.53 g of carbonamide and dissolve them in 50 mL of deionized water to obtain a mixed solution, and then add 4 g of a Y-type molecular sieve carrier to the mixed solution to prepare a suspension;

[0110] The suspension was heated from 20°C to 90°C at a heating rate of 5°C / min and stirred at a constant temperature of 60r / m for 7 hours, then the stirring was stopped and the temperature was naturally cooled, and the precipitation was aged at room temperature for 10 hours;

[0111] The aged product is filtered, washed, dried and roasted, and is pressed into tablets and sieved to 40-60 meshes to obtain the catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics.

[0112] This comparative example also provides a method for producing oil by pyrolysis of waste plastics, the method comprising:

[0113] 1g of the catalyst provided in this comparative example was loaded into the middle constant temperature zone of a quartz tube reactor (a gas inlet was provided at the top of the quartz tube reactor and a product outlet was provided at the bottom), waste plastics were loaded into the quartz sleeve, and 1g of waste polypropylene plastics was loaded into the quartz sleeve and placed in the quartz tube reaction tube and suspended above the catalyst bed. Figure 1 As shown; the distance between the top of the catalyst and the gas outlet of the raw material filling container is 70mm; wherein, the inner diameter of the quartz tube reactor is 18mm and the length is 300mm, and the inner diameter of the quartz sleeve is 14mm and the length is 60mm;

[0114] The entire quartz tube reactor is placed on an infrared rapid heating fixed bed, nitrogen is introduced into the quartz tube reactor, and the quartz tube reactor is heated from 20°C to 550°C at a heating rate of 20°C / s using the infrared rapid heating fixed bed and kept at a constant temperature for 600s, the waste plastic in the quartz sleeve is pyrolyzed to produce volatiles, and the volatiles are catalytically cracked and upgraded by the catalyst in the quartz tube reactor before being condensed into liquid fuel; wherein, the N2 gas flow rate is 200mL / min;

[0115] The products after catalytic cracking and upgrading are cooled and collected in a cold trap (-25°C) to obtain liquid oil products and gas products.

[0116] The gas products were tested by gas chromatography, and the liquid oil products were tested by simulated distillation. Figure 2 and Figure 3 shown.

[0117] The light component content of the oil product was 76.0wt.%, the gas product yield was 35.3wt.%, and the yields of H2 and CH4 in the gas product were 218mL / g waste plastic and 118mL / g waste plastic, respectively. In addition, no obvious residue was found at the outlet of the quartz tube after the reaction.

Claims

1. A method for preparing a catalyst for catalytic upgrading of volatile products from pyrolysis of waste plastics, wherein: The preparation method comprises: Mixing nickel salt, carbonamide and water to obtain a mixed solution, and mixing the mixed solution with a Y-type molecular sieve to obtain a suspension; The suspension is heated from room temperature to a first temperature of 60-75°C at a first heating rate of 5-10°C / min and stirred at a constant temperature for 1-2.5 hours, and then heated to a second temperature of 75-85°C at a second heating rate of 1-5°C / min and stirred at a constant temperature for 2-3.5 hours, and the second heating rate is greater than the first heating rate, and the second temperature is greater than the first temperature, and further heated to a third temperature of 88-92°C at a third heating rate of 1-5°C / min and stirred at a constant temperature for 4-8 hours, and then the stirring is stopped and the suspension is aged at 15-30°C for 10-16 hours; The product after aging treatment is subjected to solid-liquid separation, washing, drying and roasting to obtain a catalyst for catalytic upgrading of volatiles from pyrolysis of waste plastics.

2. The preparation method according to claim 1, wherein The stirring speed of the constant temperature stirring at the first temperature is greater than the stirring speed of the constant temperature stirring at the second temperature, and the stirring speed of the constant temperature stirring at the second temperature is greater than the stirring speed of the constant temperature stirring at the third temperature.

3. The preparation method according to claim 2, wherein The stirring speed of the constant temperature stirring at the first temperature is 70-110 r / m; the stirring speed of the constant temperature stirring at the second temperature is 50-70 r / m; the stirring speed of the constant temperature stirring at the third temperature is 30-50 r / m.

4. The preparation method according to claim 1, wherein The preparation method further comprises tableting and screening the calcined product to a particle size not exceeding 40 meshes; and / or The Y-type molecular sieve has been pre-treated with steam and acid; and / or The mass ratio of nickel, carbonamide and Y-type molecular sieve in nickel nitrate is 0.1-0.3:0.3-0.9:1; and / or Taking the total mass of the mixed solution as 100%, the mass content of water in the mixed solution is more than 65%.

5. The catalyst for catalytic upgrading of volatile products from pyrolysis of waste plastics prepared by the method for preparing the catalyst for catalytic upgrading of volatile products from pyrolysis of waste plastics according to any one of claims 1 to 4.

6. The catalyst according to claim 5, wherein Taking the total mass of the catalyst as 100%, the mass content of Ni in the catalyst is 1.0-20.0wt.% or 2.0-10.0wt.%.

7. A method for producing oil by pyrolysis of waste plastics, wherein: The method includes: The catalyst for catalytic upgrading of volatile products from pyrolysis of waste plastics according to claim 5 or 6 is loaded into a reactor, the waste plastics are loaded into a raw material loading container and the raw material loading container is placed above the catalyst loading position in the reactor, and the distance between the top of the catalyst and the gas outlet of the raw material loading container is 60-80 mm; A protective gas is filled into the reactor from the top of the reactor, and the reactor is heated. Under the protective gas atmosphere, the waste plastic in the raw material filling container is pyrolyzed to produce volatiles, and the volatiles are catalytically cracked by a catalyst before being condensed into liquid fuel; The catalytic cracking products are cooled and collected to obtain the oil.

8. The method according to claim 7, wherein: The method also includes activating the catalyst in a mixed gas flow of H2 and N2 before the catalyst is used; and / or The catalytic cracking products are cooled and collected using a cold trap, the temperature of which is -25°C.

9. The method according to claim 7, wherein: The mass ratio of catalyst to waste plastic is 0.1-2.0 or 0.25-1.0; and / or Heating the reactor to 500-600°C; and / or The heating rate for heating the reactor is 1-20°C / s or 15-20°C / s.

10. The method according to claim 7, wherein: The waste plastics include one or a combination of two or more of polyethylene, polystyrene and polypropylene.

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