Oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst and application thereof

Abstract

The invention discloses an oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst and application thereof, and belongs to the technical field of preparation of waste plastic co-pyrolysis catalysts.The oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalysts.The oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst is prepared by the steps that firstly, a ZMQ-1 molecular sieve is subjected to chambering treatment through a Na2CO3 solution with the concentration being 2.5-3.2 mol / L, the ZMQ-1 molecular sieve is heated to 280-340 DEG C under the protection of nitrogen after being dried, water vapor is introduced for surface activating treatment, and then the ZMQ-1 molecular sieve is drying again, and loading nickel and boron on the Ni-ZMQ-1 molecular sieve to obtain a modified ZMQ-1 molecular sieve; baking and deoxidizing the semi-carbonized moso bamboo powder to obtain modified moso bamboo powder; the oxygen-rich waste plastics, the hydrogen-rich waste plastics, the modified moso bamboo powder and the modified ZMQ-1 molecular sieves are added into a pyrolysis reactor, and co-pyrolysis reaction is carried out under the normal pressure condition. According to the method, the nickel-boron modified ZMQ-1 molecular sieve catalyst is adopted to catalyze the co-pyrolysis reaction of the oxygen-rich waste plastics (PC), the hydrogen-rich waste plastics (PE or PP) and the modified moso bamboo powder under the conditions of normal pressure and no need of an external hydrogen source, the oxygen-containing compound proportion of the prepared bio-oil is lower than 6%, and the aromatic hydrocarbon yield is higher than 46%.

Description

Technical Field

[0001] This invention relates to the field of co-pyrolysis catalyst preparation technology for waste plastics, specifically to an oxygen-rich and hydrogen-rich co-pyrolysis catalyst for waste plastics and its application. Background Technology

[0002] Oxygen-rich waste plastics (such as polycarbonate PC) and hydrogen-rich waste plastics (such as polyethylene PE) are common types of waste plastics. Plastic pyrolysis, as a method for the resource recovery of waste plastics, can convert waste plastics into products such as pyrolysis oil, pyrolysis gas, and coke.

[0003] However, the pyrolysis oil produced by oxygen-enriched waste plastic pyrolysis contains a large amount of oxygen-containing compounds, resulting in poor oil quality and low stability. Furthermore, there is still room for improvement in the efficiency of traditional pyrolysis technology in converting waste plastics into aromatics. At the same time, upgrading processes such as hydrodeoxygenation usually require high temperature, high pressure and external hydrogen sources, which result in high energy consumption and high cost.

[0004] Based on this, the present invention designs an oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst and its application to solve the above problems. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the existing technology, the present invention provides an oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst and its application.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A co-pyrolysis catalyst for oxygen- and hydrogen-rich waste plastics involves first enlarging the pores of a ZMQ-1 molecular sieve using a 2.5–3.2 mol / L Na₂CO₃ solution. After drying, the ZMQ-1 molecular sieve is heated to 280–340 °C under nitrogen protection and surface activated by introducing steam for 0.5–0.8 h. After drying again, nickel is impregnated onto the ZMQ-1 molecular sieve, and then boron is loaded onto the Ni-ZMQ-1 molecular sieve via chemical vapor deposition. Modified ZMQ-1 molecular sieve is obtained by applying MQ-1 molecular sieve; bamboo powder is placed in a low-oxygen environment below the ignition point of bamboo for semi-carbonization treatment to obtain semi-carbonized bamboo powder, and the semi-carbonized bamboo powder is baked and deoxygenated to obtain modified bamboo powder; oxygen-rich waste plastic, hydrogen-rich waste plastic, modified bamboo powder, and modified ZMQ-1 molecular sieve are added to the pyrolysis reactor at a mass ratio of 1:3~5:0.5~1:5~8.5 and co-pyrolysis reaction is carried out under normal pressure.

[0008] Furthermore, nickel is loaded onto ZMQ-1 molecular sieves via an impregnation method: 20-22g of nickel nitrate is dissolved in deionized water to prepare an 8-8.8wt% nickel nitrate solution. 60-80g of ZMQ-1 molecular sieves are placed into an appropriate amount of nickel nitrate solution using an equal-volume impregnation method. After drying and calcination at 550-610℃, Ni-ZMQ-1 molecular sieves are obtained.

[0009] Furthermore, boron was loaded onto Ni-ZMQ-1 molecular sieve via chemical vapor deposition: N2 was introduced to purge air and water vapor at a flow rate of 120–130 mL / min, and the tube furnace was heated to 125–140 °C. After the vaporization chamber was heated to 70 °C, the N2 carrier gas carried the vaporized trimethyl borate into the reaction tube, and the temperature was maintained for 25–30 min, allowing the trimethyl borate molecules to adsorb onto the surface of the Ni-ZMQ-1 molecular sieve. Then, the temperature was increased to 380–420 °C at a rate of 6–8 °C / min, the N2 flow rate was reduced to 68–75 mL / min, and the temperature was maintained for 40–45 min. The trimethyl borate was then removed, and the product was cooled, washed, and dried to obtain the nickel-boron modified ZMQ-1 molecular sieve.

[0010] Furthermore, the steam flow rate is 0.4–0.6 mL / (min·g).

[0011] Furthermore, the semi-carbonized bamboo powder is placed in a tube furnace, vacuumed, and then nitrogen gas with a flow rate of 50-80 mL / min is introduced. The temperature is raised to different baking temperatures of 185-195℃ at a rate of 15-20℃ / min and held for 18-23 minutes to perform baking and deoxidation treatment on the semi-carbonized bamboo powder.

[0012] Furthermore, the pyrolysis furnace is heated to 595°C at a heating rate of 10–18°C / min and held for 1 minute.

[0013] Furthermore, oxygen-rich waste plastics are PC, and hydrogen-rich waste plastics are PE.

[0014] To better achieve the objectives of this invention, a method for preparing an oxygen- and hydrogen-rich waste plastic co-pyrolysis catalyst is also provided. First, a ZMQ-1 molecular sieve is subjected to pore-expansion treatment with a 2.5–3.2 mol / L Na₂CO₃ solution. After drying, the ZMQ-1 molecular sieve is heated to 280–340°C under nitrogen protection, and surface activation is performed by introducing steam for 0.5–0.8 h. After drying again, nickel is loaded onto the ZMQ-1 molecular sieve using an impregnation method. Then, boron is... Modified ZMQ-1 molecular sieves were obtained by chemical vapor deposition loading onto Ni-ZMQ-1 molecular sieves. Bamboo powder was subjected to semi-carbonization treatment in a low-oxygen environment below the ignition point of bamboo to obtain semi-carbonized bamboo powder. The semi-carbonized bamboo powder was then baked and deoxidized to obtain modified bamboo powder. Oxygen-rich waste plastics, hydrogen-rich waste plastics, modified bamboo powder, and modified ZMQ-1 molecular sieves were added to a pyrolysis reactor at a mass ratio of 1:3~5:0.5~1:5~8.5 and co-pyrolysis reaction was carried out under normal pressure.

[0015] To better achieve the objectives of this invention, this invention also provides an oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst prepared according to the preparation method described above.

[0016] To better achieve the objectives of this invention, the present invention also provides an application of the catalyst described herein in the co-pyrolysis of oxygen-rich and hydrogen-rich waste plastics.

[0017] This invention uses a nickel-boron modified ZMQ-1 molecular sieve catalyst to catalyze the co-pyrolysis reaction of oxygen-rich waste plastic (PC), hydrogen-rich waste plastic (PE or PP), and modified bamboo powder. The reaction is carried out under normal pressure and without the need for an external hydrogen source. The prepared bio-oil contains less than 6% oxygenated compounds and has an aromatic hydrocarbon yield of more than 46%. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] Example 1: First, ZMQ-1 molecular sieve (prepared using the technology disclosed in CN202410606237, a novel silicate zeolite molecular sieve ZMQ-1 and its uses, with a silica-to-alumina ratio ranging from 12.5 to 100 (20 was selected in this example)) was subjected to pore-expansion treatment with a 2.5 mol / L Na2CO3 solution. After drying, the ZMQ-1 molecular sieve was heated to 280°C under nitrogen protection and surface activated for 0.8 h by introducing water vapor at a flow rate of 0.4 mL / (min·g), and then dried again. Nickel was then loaded onto the ZMQ-1 molecular sieve using an impregnation method: 20 g of nickel nitrate (Ni(NO3)2·6H2O) was dissolved in deionized water to prepare an 8 wt% nickel nitrate solution, and 80 g of nickel nitrate was impregnated using an equal-volume impregnation method. ZMQ-1 molecular sieve was placed in an appropriate amount of nickel nitrate solution, dried, and calcined at 610℃ to obtain Ni-ZMQ-1 molecular sieve. Boron was loaded onto the Ni-ZMQ-1 molecular sieve by chemical vapor deposition: N2 was introduced to remove air and water vapor at a flow rate of 120 mL / min, the tube furnace was heated to 140℃, and the vaporization chamber was heated to 70℃. The N2 carrier gas carried the vaporized trimethyl borate into the reaction tube, and the temperature was maintained for 25 min to allow the trimethyl borate molecules to adsorb onto the surface of the Ni-ZMQ-1 molecular sieve. Then, the temperature was increased to 380℃ at a rate of 8℃ / min, the N2 flow rate was reduced to 75 mL / min, and the temperature was maintained for 40 min. The trimethyl borate was then removed, and the product was cooled, washed, and dried to obtain nickel-boron modified ZMQ-1 molecular sieve. The byproduct methanol was collected. Bamboo powder was placed in a container below the surface of the bamboo. Semi-carbonization was carried out in a low-oxygen environment at the ignition point temperature to obtain semi-carbonized bamboo powder. The semi-carbonized bamboo powder was placed in a tube furnace, and after evacuation, nitrogen gas was introduced at a flow rate of 80 mL / min. The temperature was raised to a different baking temperature of 195℃ at a rate of 15℃ / min and held for 18 min to perform baking deoxidation treatment on the semi-carbonized bamboo powder, obtaining modified bamboo powder. Oxygen-rich waste plastic (PC), hydrogen-rich waste plastic (PE), modified bamboo powder, and modified ZMQ-1 molecular sieve were added to a pyrolysis reactor at a mass ratio of 1:5:0.5:8.5 (a sandwich structure (quartz wool-mixture-quartz wool) placed in a quartz tube). Under normal pressure, the pyrolysis furnace was heated to 595℃ at a rate of 10℃ / min and held for 1 min. The components of the catalytically pyrolyzed bio-oil were analyzed online by GC / MS. The bio-oil contained 5.6% oxygenated compounds and had an aromatic hydrocarbon yield of 46.1%.

[0020] Example 2: First, ZMQ-1 molecular sieve (prepared using the technology disclosed in CN202410606237, a novel silicate zeolite molecular sieve ZMQ-1 and its uses, with a silica-to-alumina ratio ranging from 12.5 to 100 (25 was selected in this example)) was subjected to pore-expansion treatment with a 3.2 mol / L Na2CO3 solution. After drying, the ZMQ-1 molecular sieve was heated to 340°C under nitrogen protection and surface activated for 0.5 h by introducing water vapor at a flow rate of 0.6 mL / (min·g), and then dried again. Nickel was loaded onto the ZMQ-1 molecular sieve by impregnation: 22 g of nickel nitrate (Ni(NO3)2·6H2O) was dissolved in deionized water to prepare an 8.8 wt% nickel nitrate solution, and 60 g of nickel nitrate was impregnated using an equal-volume impregnation method. ZMQ-1 molecular sieve was placed in an appropriate amount of nickel nitrate solution, dried, and calcined at 550℃ to obtain Ni-ZMQ-1 molecular sieve. Boron was loaded onto the Ni-ZMQ-1 molecular sieve by chemical vapor deposition: N2 was introduced to remove air and water vapor at a flow rate of 130 mL / min, the tube furnace was heated to 125℃, and the vaporization chamber was heated to 70℃. The N2 carrier gas carried the vaporized trimethyl borate into the reaction tube, and the temperature was maintained for 30 min to allow the trimethyl borate molecules to adsorb onto the surface of the Ni-ZMQ-1 molecular sieve. Then, the temperature was increased to 420℃ at a rate of 6℃ / min, the N2 flow rate was reduced to 68 mL / min, and the temperature was maintained for 45 min. The trimethyl borate was then removed, and the product was cooled, washed, and dried to obtain nickel-boron modified ZMQ-1 molecular sieve. The byproduct methanol was collected. Bamboo powder was placed in a container below the surface of the tube. Bamboo was semi-carbonized in a low-oxygen environment at its ignition point temperature to obtain semi-carbonized bamboo powder. This powder was then placed in a tube furnace, evacuated, and purged with nitrogen at a flow rate of 50 mL / min. The temperature was increased to 185°C at a rate of 20°C / min and held for 23 minutes to deoxygenate the semi-carbonized bamboo powder, yielding modified bamboo powder. Oxygen-rich waste plastic (PC), hydrogen-rich waste plastic (PE), modified bamboo powder, and modified ZMQ-1 molecular sieve were added to a pyrolysis reactor at a mass ratio of 1:3:1:5 (a sandwich structure (quartz wool-mixture-quartz wool) placed in a quartz tube). Under normal pressure, the pyrolysis furnace was heated to 595°C at a rate of 18°C / min and held for 1 minute. The bio-oil components were analyzed online by GC / MS. The bio-oil contained 5.3% oxygenated compounds and had an aromatic hydrocarbon yield of 47.3%.

[0021] Example 3: First, ZMQ-1 molecular sieve (prepared using the technology disclosed in CN202410606237, a novel silicate zeolite molecular sieve ZMQ-1 and its uses; the silicon-to-aluminum ratio of ZMQ-1 molecular sieve ranges from 12.5 to 100 (30 was selected in this example)) was subjected to pore-expansion treatment with a 3 mol / L Na2CO3 solution. After drying, the ZMQ-1 molecular sieve was heated to 320°C under nitrogen protection and surface activated for 0.7 h by introducing water vapor at a flow rate of 0.5 mL / (min·g), and then dried again. Nickel was loaded onto the ZMQ-1 molecular sieve by impregnation: 21 g of nickel nitrate (Ni(NO3)2·6H2O) was dissolved in deionized water to prepare an 8.4 wt% nickel nitrate solution, and 72 g of nickel nitrate was impregnated using an equal-volume impregnation method. ZMQ-1 molecular sieves were placed in an appropriate amount of nickel nitrate solution, dried, and calcined at 580℃ to obtain Ni-ZMQ-1 molecular sieves. Boron was loaded onto the Ni-ZMQ-1 molecular sieves via chemical vapor deposition: N2 was introduced to purge air and water vapor at a flow rate of 125 mL / min, the tube furnace was heated to 130℃, and the vaporization chamber was heated to 70℃. The N2 carrier gas carried the vaporized trimethyl borate into the reaction tube, and the temperature was maintained for 28 min, allowing the trimethyl borate molecules to adsorb onto the surface of the Ni-ZMQ-1 molecular sieves. Then, the temperature was increased to 400℃ at a rate of 7℃ / min, the N2 flow rate was reduced to 70 mL / min, and the temperature was maintained for 42 min. The trimethyl borate was then removed, and the product was cooled, washed, and dried to obtain nickel-boron modified ZMQ-1 molecular sieves. The byproduct methanol was collected. Bamboo powder was placed below the bamboo... Semi-carbonization was performed in a low-oxygen environment at the ignition point temperature to obtain semi-carbonized bamboo powder. The semi-carbonized bamboo powder was placed in a tube furnace, and after evacuation, nitrogen gas was introduced at a flow rate of 70 mL / min. The temperature was raised to a different baking temperature of 190℃ at a rate of 18℃ / min and held for 20 min to perform baking deoxygenation treatment, yielding modified bamboo powder. Oxygen-rich waste plastic (PC), hydrogen-rich waste plastic (PE), modified bamboo powder, and modified ZMQ-1 molecular sieve were added to a pyrolysis reactor at a mass ratio of 1:4:0.6:8 (a sandwich structure (quartz wool-mixture-quartz wool) placed in a quartz tube). Under normal pressure, the pyrolysis furnace was heated to 595℃ at a rate of 15℃ / min and held for 1 min. The components of the catalytically pyrolyzed bio-oil were analyzed online by GC / MS. The bio-oil contained 5.9% oxygenated compounds and had an aromatic hydrocarbon yield of 46.7%.

[0022] Comparative Example 1: Compared with Example 3, the difference is that oxygen-rich waste plastic (PC), hydrogen-rich waste plastic (PE), modified bamboo powder, and modified ZMQ-1 molecular sieve were added to the pyrolysis reactor in a mass ratio of 1:4:0.3:8. The bio-oil contained 8.9% oxygenated compounds and had an aromatic hydrocarbon yield of 35.6%.

[0023] Comparative Example 2: Compared with Example 3, the difference is that oxygen-rich waste plastic (PC), hydrogen-rich waste plastic (PE), modified bamboo powder, and modified ZMQ-1 molecular sieve were added to the pyrolysis reactor in a mass ratio of 1:4:2:8. The bio-oil contained 7.5% oxygenated compounds, and the aromatic hydrocarbon yield was 40.9%.

[0024] Comparative Example 3: Compared with Example 3, the difference is that oxygen-rich waste plastic (PC), hydrogen-rich waste plastic (PE), modified bamboo powder, and modified ZMQ-1 molecular sieve were added to the pyrolysis reactor in a mass ratio of 2.5:2.5:2:8. The bio-oil contained 10.5% oxygenated compounds and had an aromatic hydrocarbon yield of 30.2%.

[0025] Comparative Example 4: Compared to Example 3, the bamboo powder was not modified. The bio-oil contained 8.2% oxygenated compounds and had an aromatic hydrocarbon yield of 45.4%.

[0026] This invention uses a nickel-boron modified ZMQ-1 molecular sieve catalyst to catalyze the co-pyrolysis reaction of oxygen-rich waste plastic (PC), hydrogen-rich waste plastic (PE or PP), and modified bamboo powder. The reaction is carried out under normal pressure and without the need for an external hydrogen source. The prepared bio-oil contains less than 6% oxygenated compounds and has an aromatic hydrocarbon yield of more than 46%.

[0027] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A catalyst for the co-pyrolysis of oxygen-rich and hydrogen-rich waste plastics, characterized in that, First, the ZMQ-1 molecular sieve was subjected to pore-expansion treatment with a Na2CO3 solution of concentration of 2.5-3.2 mol / L. After drying, the ZMQ-1 molecular sieve was heated to 280-340℃ under nitrogen protection and surface activated by steam for 0.5-0.8 h. After drying again, nickel was loaded onto the ZMQ-1 molecular sieve by impregnation. Then, boron was loaded onto the Ni-ZMQ-1 molecular sieve by chemical vapor deposition to obtain modified ZMQ-1 molecular sieve. Bamboo powder was placed in a low-oxygen environment below the ignition point of bamboo for semi-carbonization treatment to obtain semi-carbonized bamboo powder. The semi-carbonized bamboo powder was then baked and deoxidized to obtain modified bamboo powder. Oxygen-rich waste plastic, hydrogen-rich waste plastic, modified bamboo powder, and modified ZMQ-1 molecular sieve were added to a pyrolysis reactor at a mass ratio of 1:3-5:0.5-1:5-8.5 and carried out a co-pyrolysis reaction under normal pressure.

2. The oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst according to claim 1, characterized in that, Nickel was loaded onto ZMQ-1 molecular sieve by impregnation: 20-22 parts of nickel nitrate were dissolved in deionized water to prepare an 8-8.8 wt% nickel nitrate solution. 60-80 parts of ZMQ-1 molecular sieve were placed into an appropriate amount of nickel nitrate solution by equal volume impregnation. After drying and calcination at 550-610℃, Ni-ZMQ-1 molecular sieve was obtained.

3. The oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst according to claim 2, characterized in that, Boron was loaded onto Ni-ZMQ-1 molecular sieve via chemical vapor deposition: N2 was introduced to purge air and water vapor at a flow rate of 120–130 mL / min, and the tubular furnace was heated to 125–140 °C. After the vaporization chamber was heated to 70 °C, the N2 carrier gas carried the vaporized trimethyl borate into the reaction tube, and the temperature was maintained for 25–30 min to allow the trimethyl borate molecules to adsorb onto the surface of the Ni-ZMQ-1 molecular sieve. Then, the temperature was increased to 380–420 °C at a rate of 6–8 °C / min, the N2 flow rate was reduced to 68–75 mL / min, and the temperature was maintained for 40–45 min. The trimethyl borate was then removed, and the product was cooled, washed, and dried to obtain the nickel-boron modified ZMQ-1 molecular sieve.

4. The oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst according to claim 3, characterized in that, The steam flow rate is 0.4–0.6 mL / (min·g).

5. The oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst according to claim 4, characterized in that, The semi-carbonized bamboo powder is placed in a tube furnace, and after evacuation, nitrogen gas with a flow rate of 50-80 mL / min is introduced. The temperature is raised to different baking temperatures of 185-195℃ at a rate of 15-20℃ / min and held for 18-23 minutes to perform baking and deoxidation treatment on the semi-carbonized bamboo powder.

6. The oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst according to claim 5, characterized in that, The pyrolysis furnace is heated to 595°C at a heating rate of 10–18°C / min and held for 1 minute.

7. The oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst according to claim 6, characterized in that, Oxygen-rich waste plastics are PC, and hydrogen-rich waste plastics are PE.

8. A method for preparing an oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst according to any one of claims 1 to 7, characterized in that, First, the ZMQ-1 molecular sieve was subjected to pore-expansion treatment with a Na2CO3 solution of concentration of 2.5-3.2 mol / L. After drying, the ZMQ-1 molecular sieve was heated to 280-340℃ under nitrogen protection and surface activated by steam for 0.5-0.8 h. After drying again, nickel was loaded onto the ZMQ-1 molecular sieve by impregnation. Then, boron was loaded onto the Ni-ZMQ-1 molecular sieve by chemical vapor deposition to obtain modified ZMQ-1 molecular sieve. Bamboo powder was placed in a low-oxygen environment below the ignition point of bamboo for semi-carbonization treatment to obtain semi-carbonized bamboo powder. The semi-carbonized bamboo powder was then baked and deoxidized to obtain modified bamboo powder. Oxygen-rich waste plastic, hydrogen-rich waste plastic, modified bamboo powder, and modified ZMQ-1 molecular sieve were added to a pyrolysis reactor at a mass ratio of 1:3-5:0.5-1:5-8.5 and carried out a co-pyrolysis reaction under normal pressure.

9. An oxygen-rich and hydrogen-rich waste plastic co-pyrolysis catalyst prepared by the preparation method according to claim 8.

10. The application of a catalyst according to claim 1, 2, 3, 4, 5, 6, 7 or 9 in the co-pyrolysis of oxygen-rich and hydrogen-rich waste plastics.