A system and method for synergistic photocatalytic co-pyrolysis of marine organic solid waste

Abstract

The application discloses a kind of photothermal synergic catalysis co-pyrolysis system and method of marine organic solid waste, method includes the following steps: waste fishing net, plastic garbage and seaweed are crushed and mixed uniformly according to mass ratio (2-4):(3-5):(1-3);Mixed material and multifunctional composite photocatalyst prepared by seaweed are sent into moving bed reactor according to mass ratio (10-20):1, under the condition of concentrated solar energy leading, electric heating auxiliary, continuous co-pyrolysis is carried out;Pyrolysis product is separated by three-stage condensation to obtain heavy oil, light oil, water and gas.The method realizes the green cycle of "waste treatment", the catalyst cost is low, the degree of system intelligence is high, and provides an efficient, environmentally friendly, economically feasible innovative path for the resource utilization of marine organic solid waste.

Description

Technical Field

[0001] This invention belongs to the field of organic solid waste resource utilization and renewable energy utilization technology, specifically relating to a photothermal synergistic catalytic co-pyrolysis system and method for marine organic solid waste. Background Technology

[0002] With the intensification of human activities, marine pollution has become increasingly serious. Every year, large quantities of discarded nylon fishing nets, plastic products, and seaweed, among other organic solid waste, enter the marine ecosystem, causing severe ecological damage. Traditional landfill or incineration methods not only consume land resources but also generate secondary pollution. Pyrolysis technology, as a thermochemical conversion method, can transform organic solid waste into fuel oil, combustible gas, and charcoal materials, and has broad application prospects.

[0003] Existing technology CN116286073A, "A Method for Preparing High-Quality Pyrolysis Oil from Waste Tires Catalytic Pyrolysis Based on Concentrated Solar Heat Source," studies the use of solar energy as a heat source for the pyrolysis of waste tires or biomass, and explores the co-pyrolysis process of different organic wastes to improve product quality. However, these technologies still have significant shortcomings: First, relying solely on solar heating is greatly affected by weather, making continuous and stable operation difficult; second, catalysts are mostly purchased commercial products, resulting in high costs and underutilization of the waste's intrinsic value; third, reaction systems are mostly intermittent operations with low processing efficiency, unsuitable for large-scale applications; and finally, the lack of refined control over the products fails to maximize their economic value.

[0004] Therefore, there is an urgent need to develop a comprehensive treatment solution for marine organic solid waste that integrates stable energy supply, self-produced high-efficiency catalysts, continuous reaction, and high-value product utilization. Summary of the Invention

[0005] To address at least one of the aforementioned problems, this invention provides a photothermal synergistic catalytic co-pyrolysis system and method for marine organic solid waste.

[0006] To achieve the above objectives, the present invention employs the following technical means: The first aspect of this invention provides a photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste, comprising the following steps: Discarded fishing nets, plastic waste, and seaweed are washed, dried, and crushed separately, and then mixed evenly in a mass ratio of (2-4):(3-5):(1-3); Preparation of multifunctional composite photothermal catalyst: Phosphorus-doped biochar was prepared by seaweed; then it was mixed with HZSM-5 molecular sieve, and the active components were loaded by the equal volume impregnation method. After drying and subsequent heat treatment, the composite catalyst was obtained. The mixture and the multifunctional composite photothermal catalyst are fed into a moving bed reactor at a mass ratio of (10-20):1, and continuous co-pyrolysis is carried out under the conditions of concentrated solar energy as the main force and electric heating as the auxiliary force. The pyrolysis products are separated into heavy oil, light oil, water, and gas through three-stage condensation.

[0007] In some embodiments of the present invention, the preparation method of the phosphorus-doped biochar is as follows: waste seaweed is carbonized at 400-600 °C for 2-3 hours under an inert atmosphere, and then ground and sieved to obtain biochar; phosphoric acid solution is added to the biochar, ultrasonically impregnated and dried at 70-80 °C, and then heat-treated at 300-400 °C for 2-3 hours under an inert atmosphere to obtain phosphorus-doped biochar.

[0008] In some embodiments of the present invention, the phosphoric acid solution has a mass fraction of 8-10%, and the mass ratio of biochar to phosphoric acid is 1:(0.5-0.6).

[0009] In some embodiments of the present invention, the inert atmosphere is nitrogen, and the nitrogen flow rate is 80-100 mL / min.

[0010] In some embodiments of the present invention, the mass ratio of the phosphorus-doped biochar to the HZSM-5 molecular sieve is (3-5):1.

[0011] In some embodiments of the present invention, the SiO2 / Al2O3 molar ratio of the HZSM-5 molecular sieve is 30-80.

[0012] In some embodiments of the present invention, the loading of the active component is any of the following: a. Single metal loading: The single metal is one of Cu, Ce, Co, Mn, Fe, Pt, or Ir, and its loading amount is 0.5-2 wt% of the total catalyst mass; b. Bimetallic alloy loading: The bimetallic alloy is any two of Cu, Ce, Co, Mn and Fe, and its total loading is 0.5-2 wt% of the total mass of the catalyst. The molar ratio of the two metals is (0.5-2):1. c. Noble metal-additive loading: The noble metal is Pt or Ir, with a loading of 0.1-0.5 wt%, and CeO2 is added as an additive with a loading of 1-3 wt%.

[0013] In some embodiments of the present invention, the method for loading the active component is liquid-phase reduction or high-temperature calcination.

[0014] In some embodiments of the present invention, the temperature of the co-pyrolysis is 500-600°C and the reaction time is 40-60 min.

[0015] In some embodiments of the present invention, the condensation temperatures of the three-stage condensation are 5 °C, -10 °C and -30 °C, respectively.

[0016] In some embodiments of the present invention, the plastic waste comprises one or more mixtures of polyethylene, polypropylene and polystyrene; the main component of the discarded fishing net is nylon 6 or nylon 66.

[0017] In some embodiments of the present invention, the catalyst is further subjected to magnetic screening for separation and recycling in the residual mixture after condensation.

[0018] After the oil and gas mixture produced by pyrolysis passes through a three-stage condensation system, the non-condensable gases are purified and partially reused as carrier gas, while the remainder is stored and utilized. The residual semi-coke and catalyst mixture are separated by magnetic separation, the catalyst is recycled, and the semi-coke is used as fuel or to prepare activated carbon.

[0019] A photothermal synergistic catalytic co-pyrolysis system for marine organic solid waste includes: a. Raw material pretreatment unit, used for cleaning, crushing and drying marine organic solid waste; b. Moving bed reactor, which is equipped with a concentrating solar energy receiving device on the outside and an electric heating wire inside as an auxiliary heat source; when the light is sufficient, the solar energy maintains the reaction temperature at 500-600°C; when the light is insufficient, the electric heating is automatically activated to assist in heating; the material is discharged after staying in the reactor for 30-60 minutes. c. A multifunctional composite photothermal catalyst circulation unit, including a catalyst preparation module and a magnetic separation module; d. A three-stage condensation and separation unit is used for the graded recovery of liquid products; e. Gas purification and storage unit; f. Central control system, used to integrate monitoring and control of the operating parameters of each unit; the central control system dynamically adjusts the solar focusing angle, auxiliary heating power and feeding rate according to real-time light intensity, reaction temperature and material flow rate.

[0020] Beneficial effects of the present invention Compared with the prior art, the present invention has the following beneficial effects: This application utilizes the resource recovery from the treatment of organic solid waste. It innovatively designs and prepares a multifunctional composite photothermal catalyst using phosphorus-doped biochar derived from marine solid waste as a carrier, HZSM-5 molecular sieve as an acidic center, and loaded with active components such as Cu, Fe-Co, and Pt. This achieves a high degree of synergy between light, heat, and chemistry. The catalyst introduces photothermal synergistic catalysis, utilizing its catalytic activity to promote the breaking of CH bonds in organic solid waste, thus improving pyrolysis efficiency. Simultaneously, it utilizes solar energy as an energy input, resulting in greater energy efficiency. This not only possesses excellent solar absorption and photothermal conversion capabilities but also effectively promotes the co-pyrolysis reaction of multi-component marine organic solid waste, significantly improving the yield (up to 88.7 wt%) and quality of liquid fuel oil (aromatic hydrocarbon content exceeding 80%). Combined with a hybrid energy system dominated by concentrated solar power and assisted by electric heating, and a moving bed continuous reactor, the stable operation and high energy efficiency of the process are ensured. The entire technical route achieves a green circular economy of "treating waste with waste," with low catalyst cost and a high degree of system intelligence, providing an efficient, environmentally friendly, and economically feasible innovative path for the resource utilization of marine organic solid waste. Attached Figure Description

[0021] Figure 1 A schematic diagram of the photothermal synergistic catalytic co-pyrolysis system of the present invention is shown. Detailed Implementation

[0022] The following examples are used to illustrate preferred embodiments of the invention. Those skilled in the art will understand that the techniques disclosed in the examples represent techniques discovered by the inventors that can be used to implement the invention, and therefore can be considered preferred embodiments for implementing the invention. However, those skilled in the art should understand from this specification that many modifications can be made to the specific embodiments disclosed herein, still yielding the same or similar results, without departing from the spirit or scope of the invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and all materials disclosed herein and cited therein are incorporated herein by reference. Many equivalent techniques of specific embodiments of the invention described herein will be recognized or can be understood by ordinary experimentation by those skilled in the art. These equivalents will be included in the claims.

[0024] A photothermal synergistic catalytic co-pyrolysis system for marine organic solid waste includes: a. Raw material pretreatment unit, used for cleaning, crushing and drying marine organic solid waste; b. Moving bed reactor, which is equipped with a concentrating solar energy receiving device on the outside and an electric heating wire inside as an auxiliary heat source; when the light is sufficient, the solar energy maintains the reaction temperature at 500-600℃; when the light is insufficient, the electric heating is automatically activated to assist in heating; the material is discharged after staying in the reactor for 30-60 minutes. c. A multifunctional composite photothermal catalyst circulation unit, including a catalyst preparation module and a magnetic separation module; d. A three-stage condensation and separation unit is used for the graded recovery of liquid products; e. Gas purification and storage unit; f. Central control system, used to integrate monitoring and control of the operating parameters of each unit; the central control system dynamically adjusts the solar focusing angle, auxiliary heating power and feeding rate according to real-time light intensity, reaction temperature and material flow rate.

[0025] A photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste includes the following steps: S1. Raw material pretreatment: Collect waste fishing nets, plastic waste and seaweed separately, wash and desalinate them, crush them to a particle size of 0.5-2 mm and then dry them for later use; S2. Raw material ratio and mixing: Mix the pretreated waste fishing nets, plastic waste and seaweed evenly according to the mass ratio of (2-4):(3-5):(1-3) to obtain the mixture. S3. Preparation of multifunctional composite photothermal catalyst: Waste seaweed was carbonized at 500℃ for 2 hours under an inert atmosphere, and then ground and sieved to obtain biochar; 8-10% phosphoric acid solution was added to the biochar, ultrasonically impregnated and dried at 80℃, and then heat-treated at 350℃ for 3 hours under N2 atmosphere to obtain phosphorus-doped biochar; Subsequently, the obtained phosphorus-doped biochar was mixed with HZSM-5 molecular sieve at a mass ratio of (3-5):1, and active components of transition metals or noble metals were loaded by equal volume impregnation method. After drying and calcination / reduction, a multifunctional composite photothermal catalyst with strong acid center, excellent photothermal conversion ability and multiple catalytic functions was obtained. The active component is any one of the following: a. Single metal support: one of Cu, Ce, Co, Mn, Fe, Pt, or Ir, with a loading of 0.5-2 wt% of the total catalyst mass; b. Bimetallic alloy loading: Two alloys are selected from Cu, Ce, Co, Mn and Fe, and the total loading is 0.5-2 wt% of the total mass of the catalyst, with the molar ratio of the two metals being (0.5-2):1; c. Precious metal-additive loading: The precious metal is Pt or Ir, with a loading of 0.1-0.5 wt%, and CeO2 is added as an additive with a loading of 1-3 wt%. S4. Continuous co-pyrolysis reaction: The mixture obtained in step S2 and the catalyst prepared in step S3 are fed into a moving bed reactor at a mass ratio of (10-20):1; the concentrating solar energy system is started to heat the reactor. When the light is sufficient, the reaction temperature is maintained at 500-600 ℃ by solar energy; when the light is insufficient, electric heating is automatically activated to assist in heating; the material is discharged after staying in the reactor for 30-60 minutes. S5. Product Separation and Recovery: The oil and gas mixture generated by pyrolysis is sequentially passed through a three-stage condensation system at 5℃, -10℃ and -30℃ to collect heavy oil, light oil and aqueous phase respectively; non-condensable gases are purified and partially reused as carrier gas, and the remainder is stored and utilized; the residual semi-coke and catalyst mixture are separated by magnetic separation, the catalyst is recycled, and the semi-coke is used as fuel or to prepare activated carbon. S6. Intelligent control: The entire system is monitored by a central controller, which dynamically adjusts the solar focusing angle, auxiliary heating power, and feeding rate based on real-time light intensity, reaction temperature, and material flow rate.

[0026] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0027] Example 1 1. Take discarded nylon 6 fishing nets, mixed plastic waste (polyethylene PE: polypropylene PP: polystyrene PS = 3:2:1) and dried Sargassum, wash and desalinate them separately, crush them to about 1 mm and dry them.

[0028] 2. Weigh out the three materials in a mass ratio of 3:4:2 and mix them evenly.

[0029] 3. Preparation of multifunctional composite photothermal catalysts: a. Carbonize 10 g of Sargassum at 500 °C for 2 hours under N2 atmosphere, and then grind it to obtain biochar; b. Mix biochar with 5 g of 10% phosphoric acid solution, ultrasonically impregnate for 1 hour, dry at 80 °C and then heat-treat at 350 °C for 3 hours to obtain phosphorus-doped biochar; c. Mix 15 g of the above phosphorus-doped biochar with 5 g of HZSM-5 molecular sieve (SiO2 / Al2O3=50) to obtain a support; d. Supported copper nanoparticles: Prepare a solution containing 0.1 mol / L copper nitrate, the volume of which is just enough to impregnate 10 g of the above support. Slowly add the solution dropwise onto the support and let it stand for 12 hours. Then dry it at 80 °C and reduce it at 350 °C for 2 hours under a N2 atmosphere to obtain a multifunctional composite photothermal catalyst containing 2 wt% Cu / HZSM-5.

[0030] 4. In a moving bed reactor, continuously feed the mixture (containing 1 g / h of catalyst) at a rate of 15 g / h. Turn on the concentrating solar system and set the target temperature to 550 °C. On sunny days, solar energy can independently maintain the reaction temperature; on cloudy days, electric heating automatically supplements the energy to ensure a constant temperature. The material remains in the reactor for 45 minutes.

[0031] 5. The pyrolysis oil and gas are separated by three-stage condensation (5 °C, -10 °C, -30 °C).

[0032] Results: The yield of light oil was 88.7 wt%, of which the aromatic hydrocarbon content was 82.3 wt%; the gas yield was 25.6 wt%, with H2+CH4 accounting for 70.1%; and the semi-coke yield was 25.7 wt%.

[0033] The catalyst was recycled 5 times after magnetic separation, and its activity decreased by less than 3%.

[0034] Example 2 1. Take discarded nylon 6 fishing nets, mixed plastic waste (PE:PP:PS=3:2:1) and dried Sargassum, wash and desalinate them separately, crush them to about 1 mm and dry them.

[0035] 2. Weigh out the three materials in a mass ratio of 2:4:3 and mix them evenly.

[0036] 3. Preparation of multifunctional composite photothermal catalysts: a. Carbonize 10 g of Sargassum at 500 °C for 2 hours under N2 atmosphere, and then grind it to obtain biochar.

[0037] b. Mix biochar with 5 g of 10% phosphoric acid solution, ultrasonically impregnate for 1 hour, dry at 80 °C, and then heat-treat at 350 °C for 3 hours to obtain phosphorus-doped biochar.

[0038] c. Mix 15 g of the above phosphorus-doped biochar with 5 g of HZSM-5 molecular sieve (SiO2 / Al2O3=50) to obtain a support.

[0039] d. Supported iron-cobalt bimetallic alloy: 0.1 mol / L iron nitrate and 0.1 mol / L cobalt nitrate solutions were prepared separately and mixed at a Fe:Co molar ratio of 1:1. The total volume was used to impregnate 10 g of the support using an equal-volume impregnation method. After drying at 80 °C, the mixture was reduced at 500 °C for 2 hours in a H2 / N2 (10% / 90%) mixed gas to obtain a Fe-Co / HZSM-5 multifunctional composite photothermal catalyst containing 1 wt% Fe and 1 wt% Co.

[0040] 4. In a moving bed reactor, continuously feed the mixture (containing 1 g / h of catalyst) at a rate of 15 g / h. Turn on the concentrating solar power system and set the target temperature to 500 °C. On sunny days, solar energy can independently maintain the reaction temperature; on cloudy days, electric heating automatically supplements the energy to ensure a constant temperature. The material remains in the reactor for 45 minutes.

[0041] 5. The pyrolysis oil and gas are separated by three-stage condensation (5 °C, -10 °C, -30 °C).

[0042] Results: Light oil yield was 85.2 wt%, aromatic hydrocarbon content was 79.8 wt%; gas yield was 28.6 wt%, H2+CH4 accounted for 68.1%; semi-coke yield was 23.7 wt%.

[0043] The catalyst can be recycled 5 times after magnetic separation, and its activity decreases by less than 5%.

[0044] Example 3 1. Take discarded nylon 6 fishing nets, mixed plastic waste (PE:PP:PS=3:2:1) and dried Sargassum, wash and desalinate them separately, crush them to about 1 mm and dry them.

[0045] 2. Weigh out the three materials in a mass ratio of 3:3:4 and mix them evenly.

[0046] 3. Preparation of multifunctional composite photothermal catalysts: a. Carbonize 10 g of Sargassum at 500 °C for 2 hours under N2 atmosphere, and then grind it to obtain biochar.

[0047] b. Mix biochar with 5 g of 10% phosphoric acid solution, ultrasonically impregnate for 1 hour, dry at 80 °C, and then heat-treat at 350 °C for 3 hours to obtain phosphorus-doped biochar.

[0048] c. Mix 15 g of the above phosphorus-doped biochar with 5 g of HZSM-5 molecular sieve (SiO2 / Al2O3=50) to obtain a support.

[0049] d. Supported platinum-cerium dioxide additive system: A mixed solution containing 0.05 mol / L chloroplatinic acid and 0.2 mol / L cerium nitrate was prepared, and 10 g of support was impregnated using an equal-volume impregnation method. After drying at 80 °C, the solution was calcined at 550 °C for 3 hours in air to form CeO2 and Pt oxides. Before use, the solution was reduced in H2 at 400 °C for 1 hour to obtain a Pt-CeO2 / HZSM-5 multifunctional composite photothermal catalyst containing 0.3 wt% Pt and 2 wt% CeO2.

[0050] 4. In a moving bed reactor, continuously feed the mixture (containing 1 g / h of catalyst) at a rate of 15 g / h. Turn on the concentrating solar power system and set the target temperature to 500 °C. On sunny days, solar energy can independently maintain the reaction temperature; on cloudy days, electric heating automatically supplements the energy to ensure a constant temperature. The material remains in the reactor for 45 minutes.

[0051] 5. The pyrolysis oil and gas are separated by three-stage condensation (5 °C, -10 °C, -30 °C).

[0052] Results: Light oil yield was 86.5 wt%, aromatic hydrocarbon content was 80.5 wt%; gas yield was 30.6 wt%, H2+CH4 accounted for 63.1%; semi-coke yield was 23.4 wt%.

[0053] Example 4 1. Take discarded nylon 6 fishing nets, mixed plastic waste (PE:PP:PS=3:2:1) and dried Sargassum, wash and desalinate them separately, crush them to about 1 mm and dry them.

[0054] 2. Weigh out the three materials in a mass ratio of 2:4:4 and mix them evenly.

[0055] 3. Preparation of multifunctional composite photothermal catalysts: a. Carbonize 10 g of Sargassum at 500 °C for 2 hours under N2 atmosphere, and then grind it to obtain biochar.

[0056] b. Mix biochar with 5 g of 10% phosphoric acid solution, ultrasonically impregnate for 1 hour, dry at 80 °C, and then heat-treat at 350 °C for 3 hours to obtain phosphorus-doped biochar.

[0057] c. Mix 15 g of the above phosphorus-doped biochar with 5 g of HZSM-5 molecular sieve (SiO2 / Al2O3=50) to obtain a support.

[0058] d. Supported iridium-cerium dioxide additive system: A mixed solution containing 0.07 mol / L chloroiridium acid and 0.2 mol / L cerium nitrate was prepared, and 10 g of support was impregnated using an equal-volume impregnation method. After drying at 80 °C, the solution was calcined at 550 °C for 3 hours in air to form CeO2 and Ir oxides. Before use, the solution was reduced in H2 at 400 °C for 1 hour to obtain an Ir-CeO2 / HZSM-5 multifunctional composite photothermal catalyst containing 0.3 wt% Ir and 3 wt% MnOx.

[0059] 4. In a moving bed reactor, continuously feed the mixture (containing 1 g / h of catalyst) at a rate of 15 g / h. Turn on the concentrating solar system and set the target temperature to 500°C. On sunny days, solar energy can independently maintain the reaction temperature; on cloudy days, electric heating automatically supplements the energy to ensure a constant temperature. The material remains in the reactor for 45 minutes.

[0060] 5. The pyrolysis oil and gas are separated by three-stage condensation (5°C, -10°C, -30°C).

[0061] Results: Light oil yield was 83.5 wt%, aromatic hydrocarbon content was 77.8 wt%; gas yield was 28.6 wt%, H2+CH4 accounted for 60.6%; semi-coke yield was 21.4 wt%.

[0062] Example 5 1. Take discarded nylon 6 fishing nets, mixed plastic waste (PE:PP:PS=3:2:1) and dried Sargassum, wash and desalinate them separately, crush them to about 1 mm and dry them.

[0063] 2. Weigh out the three materials in a mass ratio of 4:4:2 and mix them evenly.

[0064] 3. Preparation of multifunctional composite photothermal catalysts: a. Carbonize 10 g of Sargassum at 500 °C for 2 hours under N2 atmosphere, and then grind it to obtain biochar.

[0065] b. Mix biochar with 5 g of 10% phosphoric acid solution, ultrasonically impregnate for 1 hour, dry at 80 °C, and then heat-treat at 350 °C for 3 hours to obtain phosphorus-doped biochar.

[0066] c. Mix 15 g of the above phosphorus-doped biochar with 5 g of HZSM-5 molecular sieve (SiO2 / Al2O3=50) to obtain a support.

[0067] d. Manganese-cerium dioxide loading system: Prepare 0.1 mol / L manganese nitrate and 0.2 mol / L cerium nitrate solutions respectively, and impregnate 10 g of carrier using the equal volume impregnation method. To ensure an appropriate Mn to Ce ratio, it can be adjusted according to the required molar ratio, for example, a Mn to Ce molar ratio of 1:1.

[0068] After drying at 80 °C, the catalyst was reduced at 500 °C for 2 hours in a H2 / N2 (10% / 90%) mixed gas to obtain a Mn-CeO2 / HZSM-5 multifunctional composite photothermal catalyst containing 1 wt% Mn and 2 wt% CeO2.

[0069] 4. In a moving bed reactor, continuously feed the mixture (containing 1 g / h of catalyst) at a rate of 15 g / h. Turn on the concentrating solar power system and set the target temperature to 500 °C. On sunny days, solar energy can independently maintain the reaction temperature; on cloudy days, electric heating automatically supplements the energy to ensure a constant temperature. The material remains in the reactor for 45 minutes.

[0070] 5. The pyrolysis oil and gas are separated by three-stage condensation (5 °C, -10 °C, -30 °C).

[0071] Results: Light oil yield was 80.5 wt%, aromatic hydrocarbon content was 77.9 wt%; gas yield was 29.6 wt%, H2+CH4 accounted for 65.1%; semi-coke yield was 27.6 wt%.

[0072] The catalyst can be recycled 5 times after magnetic separation, and its activity decreases by less than 5%.

[0073] Comparative Example 1 1. Take discarded nylon 6 fishing nets, mixed plastic waste (PE:PP:PS=3:2:1) and dried Sargassum, wash and desalinate them separately, crush them to about 1 mm and dry them.

[0074] 2. Weigh out the three materials in a mass ratio of 3:4:2 and mix them evenly.

[0075] 3. Preparation of multifunctional composite photothermal catalysts: a. Carbonize 10 g of Sargassum at 500 °C for 2 hours under N2 atmosphere, and then grind it to obtain biochar.

[0076] b. Mix biochar with 5 g of 10% phosphoric acid solution, ultrasonically impregnate for 1 hour, dry at 80 °C, and then heat-treat at 350 °C for 3 hours to obtain phosphorus-doped biochar.

[0077] c. Mix 15 g of the above phosphorus-doped biochar with 5 g of HZSM-5 molecular sieve (SiO2 / Al2O3=50) to obtain a support.

[0078] 4. In a moving bed reactor, continuously feed the mixture (containing 1 g / h of catalyst) at a rate of 15 g / h. Turn on the concentrating solar power system and set the target temperature to 500 °C. On sunny days, solar energy can independently maintain the reaction temperature; on cloudy days, electric heating automatically supplements the energy to ensure a constant temperature. The material remains in the reactor for 45 minutes.

[0079] 5. The pyrolysis oil and gas are separated by three-stage condensation (5 °C, -10 °C, -30 °C).

[0080] Results: Light oil yield was 54.5 wt%, aromatic hydrocarbon content was 49.4 wt%; gas yield was 15.9 wt%, H2+CH4 accounted for 50.1%; semi-coke yield was 20.7 wt%.

[0081] Comparative Example 2 1. Take discarded nylon 6 fishing nets, mixed plastic waste (PE:PP:PS=3:2:1) and dried Sargassum, wash and desalinate them separately, crush them to about 1 mm and dry them.

[0082] 2. Weigh out the three materials in a mass ratio of 3:4:2 and mix them evenly.

[0083] 3. Under the same system and conditions, commercially available HZSM-5 molecular sieve (SiO2 / Al2O3=30) was used to replace the self-made composite catalyst.

[0084] 4. In a moving bed reactor, continuously feed the mixture (containing 1 g / h of catalyst) at a rate of 15 g / h. Turn on the concentrating solar power system and set the target temperature to 500 °C. On sunny days, solar energy can independently maintain the reaction temperature; on cloudy days, electric heating automatically supplements the energy to ensure a constant temperature. The material remains in the reactor for 45 minutes.

[0085] 5. The pyrolysis oil and gas are separated by three-stage condensation (5 °C, -10 °C, -30 °C).

[0086] Results: Light oil yield was 45.1 wt%, aromatic hydrocarbon content was 50.3 wt%; gas yield was 17.3 wt%, H2+CH4 accounted for 40.6%; semi-coke yield was 22.5 wt%.

[0087] Table 1. Pyrolysis oil production efficiency (wt%) of the methods described in Examples 1-5 and Comparative Examples 1-2

[0088] The results show: Compared with Example 1, the catalyst used in Comparative Example 1 did not have active components loaded with transition metals or noble metals. Under the condition of treating the same raw materials, the yield of light oil decreased by 38.6% and the gas yield decreased by 37.9%. In Comparative Example 2, HZSM-5 molecular sieve was used as catalyst. Under the condition of treating the same raw materials, the yield of light oil decreased by 49.2% and the gas yield decreased by 32.4%.

[0089] Examples 2-5 used different transition metals or noble metals as active components for loading, and their pyrolysis efficiencies varied slightly, but were all significantly better than Comparative Examples 1 and 2. Among them, the treatment method for marine organic solid waste based on Cu / HZSM-5 photothermal synergistic catalytic co-pyrolysis adopted in Example 1 had the strongest photothermal effect and the highest cost-effectiveness, exhibiting the best pyrolysis efficiency.

[0090] The catalyst prepared by the method of this application can be reused through magnetic screening. It has been verified that the catalyst can be recycled 5 times after magnetic separation with an activity decrease of less than 5%, which shows a very good recycling effect. The solution of this application not only realizes green recycling of waste to treat waste, but also saves costs to a great extent.

[0091] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by this application.

Claims

1. A photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste, characterized in that, Includes the following steps: Discarded fishing nets, plastic waste, and seaweed are washed, dried, and crushed separately, and then mixed evenly in a mass ratio of (2-4):(3-5):(1-3); Preparation of multifunctional composite photothermal catalyst: Phosphorus-doped biochar was prepared by seaweed; then it was mixed with HZSM-5 molecular sieve, and the active components were loaded by the equal volume impregnation method. After drying and subsequent heat treatment, the composite catalyst was obtained. The mixture and the multifunctional composite photothermal catalyst are fed into a moving bed reactor at a mass ratio of (10-20):1, and continuous co-pyrolysis is carried out under the conditions of concentrated solar energy as the main force and electric heating as the auxiliary force. The pyrolysis products are separated into heavy oil, light oil, water, and gas through three-stage condensation.

2. The photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste according to claim 1, characterized in that, The method for preparing the phosphorus-doped biochar is as follows: waste seaweed is carbonized at 400-600 °C for 2-3 hours under an inert atmosphere, ground and sieved to obtain biochar; phosphoric acid solution is added to the biochar, ultrasonically impregnated and dried at 70-80 °C, and then heat-treated at 300-400 °C for 2-3 hours under an inert atmosphere to obtain phosphorus-doped biochar.

3. The photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste according to claim 2, characterized in that, The phosphoric acid solution has a mass fraction of 8-10%, and the mass ratio of biochar to phosphoric acid is 1:(0.5-0.6).

4. The photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste according to claim 1, characterized in that, The mass ratio of the phosphorus-doped biochar to the HZSM-5 molecular sieve is (3-5):

1.

5. The photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste according to claim 2, characterized in that, The SiO2 / Al2O3 molar ratio of the HZSM-5 molecular sieve is 30-80.

6. The photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste according to claim 1, characterized in that, The loading of the active component is any of the following: a. Single metal loading: The single metal is one of Cu, Ce, Co, Mn, Fe, Pt, or Ir, and its loading amount is 0.5-2 wt% of the total catalyst mass; b. Bimetallic alloy loading: The bimetallic alloy is any two of Cu, Ce, Co, Mn and Fe, and its total loading is 0.5-2 wt% of the total mass of the catalyst. The molar ratio of the two metals is (0.5-2):

1. c. Noble metal-additive loading: The noble metal is Pt or Ir, with a loading of 0.1-0.5 wt%, and CeO2 is added as an additive with a loading of 1-3 wt%.

7. The photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste according to claim 6, characterized in that, The active component is loaded using either liquid-phase reduction or high-temperature calcination.

8. The photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste according to claim 1, characterized in that, The co-pyrolysis temperature is 500-600℃, and the reaction time is 40-60 min.

9. The photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste according to claim 1, characterized in that, The condensation temperatures of the three-stage condenser are 5 °C, -10 °C, and -30 °C, respectively.

10. The photothermal synergistic catalytic co-pyrolysis method for marine organic solid waste according to claim 1, characterized in that, It also includes the step of separating and recycling the catalyst from the residual mixture after condensation using magnetic screening.

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