Organic solid waste thermoelectric cascade catalytic conversion system and method

Abstract

The invention provides an organic solid waste thermoelectric cascade catalytic conversion system and method. The organic solid waste thermoelectric cascade catalytic conversion system comprises a hydrolysis reactor, an electro-catalytic reactor, a catalyst and a heat recovery system, the hydrolysis reactor converts waste plastics and lignocellulose biomass into intermediates through a thermal catalytic reaction, and the intermediates comprise ethylene glycol and small molecular saccharides. According to the organic solid waste thermoelectric cascade catalytic conversion system and method, in the hydrolysis reaction process, industrial waste heat is adopted to heat a reaction system, a real-time temperature and pressure control system is combined, it is ensured that the hydrolysis reaction is conducted at the set optimal temperature and pressure, and therefore energy consumption is effectively reduced, and especially in a hydrolysis reactor, the energy consumption is reduced; and the heat recovery system can recover waste heat generated in the reaction process and reuse the waste heat, so that the temperature stability in the reaction process is maintained, and the energy utilization efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of recycling and conversion of organic solid waste, and specifically to a thermoelectric cascade catalytic conversion system and method for organic solid waste. Background Art

[0002] With the widespread use of plastic products, waste plastics, especially hard-to-degrade plastics such as polyethylene terephthalate (PET), have become the main source of global environmental pollution. At the same time, lignocellulosic biomass, as another type of organic solid waste, whose main sources include agricultural waste (such as rice straw and wheat straw) and forestry waste (such as bark and wood chips), also faces challenges in efficient recycling and resource utilization due to its complex composition and stable structure.

[0003] Existing technologies such as mechanical recycling, thermochemical recycling, and catalytic conversion, although reducing waste accumulation to a certain extent, still have problems such as low energy efficiency and poor selectivity. Mechanical recycling is suitable for single plastic types but has poor treatment effects on mixed plastics; thermochemical recycling has high energy consumption and complex products; although catalytic conversion technology can improve conversion efficiency, there are still bottlenecks in dealing with complex waste. For lignocellulosic biomass, traditional thermochemical methods such as combustion and gasification have low efficiency and high pollution, while biochemical methods (such as enzymatic hydrolysis and fermentation) have slow reaction rates and high costs.

[0004] In summary, developing an innovative technology that combines efficient energy utilization and highly selective conversion, capable of realizing the co-treatment of waste plastics and lignocellulosic biomass, is the key to promoting the development of organic solid waste treatment technology towards green and efficient directions. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a thermoelectric cascade catalytic conversion system and method for organic solid waste, which solves the problems of low energy efficiency and poor selectivity in waste recycling.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A thermoelectric cascade catalytic conversion system and method for organic solid waste, comprising:

[0007] A hydrolysis reactor, an electrocatalytic reactor, a catalyst, and a heat recovery system;

[0008] The hydrolysis reactor converts waste plastics and lignocellulosic biomass into intermediates through thermocatalytic reactions, and the intermediates include ethylene glycol and small molecule sugars;

[0009] The hydrolysis reactor is a circulating flow reactor, which heats the reaction system by solar energy or industrial waste heat, and combines with a temperature control system to automatically stop heating after reaching the set temperature, thereby ensuring the efficient progress of the reaction;

[0010] The electrocatalytic reactor is used to convert the intermediates generated by the hydrolysis reaction into aromatic hydrocarbons and ketone compounds;

[0011] The catalyst includes a thermal catalyst for the depolymerization of organic solid waste and an electrocatalyst for the high-value catalytic conversion of small molecules after depolymerization;

[0012] The heat recovery system includes a heat exchanger, a heat conduit, and a heat storage device. By recovering the waste heat during the reaction process and introducing it into the reactor, it ensures that the reaction process proceeds stably under low energy consumption conditions and maximizes the energy utilization efficiency;

[0013] The hydrolysis reactor process follows a thermal catalytic reaction kinetic model, and the reaction rate of the thermal catalytic reaction kinetic model is:

[0014] r hydrolysis = k(T)·C raw

[0015] where r hydrolysis is the hydrolysis reaction rate, is the reaction rate constant related to temperature, A is the pre-exponential factor, E a is the activation energy, R is the gas constant, T is the reaction temperature, and C raw is the raw material concentration;

[0016] In this hydrolysis reactor, the temperature and pressure are maintained under optimal reaction conditions through a real-time control system. For example, the reaction temperature can be controlled at 120 - 180 °C, and the reaction pressure is controlled at 0.5 - 5 MPa. During this reaction process, the heat is recovered through the heat recovery system, and the waste heat is used to ensure the stability of the temperature inside the reactor to maintain an efficient reaction;

[0017] The relationship between the current density and the voltage in the electrocatalytic cell follows the Nernst equation, and the reaction rate is described by the Tafel equation. The formula is:

[0018]

[0019] where i is the current density, i 0 is the exchange current density, α is the charge transfer coefficient, n is the number of electron transfers, F is the Faraday constant, E is the electrode potential, and E 0 is the standard electrode potential, and R is the gas constant and T is the reaction temperature.

[0020] Preferably, the heat recovery efficiency in the heat recovery system is estimated through a heat conduction model. The formula is as follows:

[0021] Q rec = α·A·ΔT

[0022] where Qrec $Q$ is the recovered heat, $\alpha$ is the heat transfer coefficient, $A$ is the heat exchanger area, and $\Delta T$ is the temperature difference.

[0023] Preferably, the organic solid waste is mainly lignocellulosic biomass and polyethylene terephthalate. In the hydrolysis reaction, sodium hydroxide or potassium hydroxide is used as the basic catalyst, and the addition amount of the catalyst is 0.5 to 3 wt%. The hydrolysis reactor includes a temperature and pressure control system and a heat gradient reaction device. The temperature and pressure control system includes multiple temperature sensors, pressure sensors, and a real-time feedback control device to ensure that the temperature and pressure in the reactor are maintained within a preset optimal range, ensuring an efficient organic solid waste conversion process.

[0024] Preferably, the electrocatalytic reactor includes an electrolytic cell, and the anode and cathode in the electrolytic cell are respectively used to generate high-value-added chemicals and green hydrogen.

[0025] Preferably, the hydrolysis reactor and the electrocatalytic reactor are flexibly connected, capable of combining thermal energy and electrical energy, giving full play to the advantages of thermal catalysis and electrocatalysis, promoting the efficient progress of the reaction process, and ensuring the maximization of energy efficiency in the co-conversion process of waste plastics and lignocellulosic biomass.

[0026] Preferably, the heat recovery system includes a heat exchanger, a heat conduit, and a heat storage device, capable of recovering the waste heat generated during the reaction process and introducing it into the reactor to maximize the energy utilization efficiency. The heat storage device is a phase change material energy storage device, capable of balancing temperature fluctuations during the reaction process and ensuring that the reaction temperature is maintained within the set range.

[0027] Preferably, the electrocatalyst of the electrocatalytic reactor is based on nickel foam metal and is loaded with inexpensive metals with high catalytic activity suitable for this system, ensuring that the catalyst has high catalytic performance within the reaction temperature range.

[0028] An organic solid waste thermoelectric cascade catalytic conversion method includes the following steps:

[0029] a. Mix the waste plastics and lignocellulosic biomass in a preset ratio, then crush them, adjust the particle size to the range suitable for the hydrolysis reaction, and feed the pretreated raw materials into the feed port of the hydrolysis reactor;

[0030] b. Add a preset amount of sodium hydroxide or potassium hydroxide to the hydrolysis reactor, with the addition amount being 0.5 to 3 wt%. Heat the reaction system by solar energy or industrial waste heat, and combine the temperature and pressure control system to maintain the temperature and pressure in the reactor within the optimal range;

[0031] c. Transport the intermediate generated by the hydrolysis reaction to the electrocatalytic reactor. By adjusting the current and voltage, highly valuable chemicals are catalytically generated at the anode, and green hydrogen is generated at the cathode;

[0032] d. Through the heat exchanger and phase change material energy storage device in the heat recovery system, recover and utilize the waste heat generated during the electrocatalytic reaction and hydrolysis reaction processes, balance the temperature fluctuations within the system, and maintain the stability of the reaction conditions;

[0033] e. After the reaction ends, collect and purify the generated highly valuable chemicals and green hydrogen respectively. The obtained chemicals can be used in fine chemical industry or material preparation, and green hydrogen can be used as clean energy.

[0034] The present invention provides an organic solid waste thermoelectric cascade catalytic conversion system and method. It has the following beneficial effects:

[0035] In the organic solid waste thermoelectric cascade catalytic conversion system and method, industrial waste heat is used to heat the reaction system during the hydrolysis reaction process. Combined with the real-time temperature and pressure control system, it ensures that the hydrolysis reaction proceeds at the set optimal temperature and pressure, thereby effectively reducing energy consumption. Especially in the hydrolysis reactor, the heat recovery system can recover the waste heat generated during the reaction process and reuse it to maintain the temperature stability of the reaction process and improve the energy utilization efficiency. The heat is recovered through heat pipes and heat exchangers, and then stored and released through the phase change material energy storage device, which can further balance the temperature fluctuations, maximize the recovery and utilization of energy, and thus greatly improve the energy efficiency of the system.

[0036] In this technical solution, when treating waste plastics and lignocellulosic biomass, advanced electrocatalytic conversion technology is adopted to further convert the intermediate generated by hydrolysis into highly valuable chemicals such as aromatic hydrocarbons and ketone compounds, and at the same time generate green hydrogen, providing clean energy. During the electrocatalytic reaction process, the current density and voltage are precisely controlled to ensure that the reaction process has high selectivity and high efficiency, avoiding the complexity of products and the generation of impurities. Therefore, the system can efficiently treat organic solid waste while increasing the added value of products, promoting the high-value utilization of waste resources, and meeting the goals of green and sustainable development. Brief Description of the Drawings

[0037] Figure 1 It is a schematic structural diagram of the present invention.

[0038] Figure 2 It is a schematic flow diagram of the present invention. Detailed Embodiments

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] As Figure 1-2 shown in the figure, the embodiments of the present invention provide an organic solid waste thermoelectric cascade catalytic conversion system and method, including a hydrolysis reactor, an electrocatalytic reactor, a catalyst, and a heat recovery system;

[0041] The hydrolysis reactor converts waste plastics and lignocellulosic biomass into intermediates through thermal catalytic reactions. The intermediates include ethylene glycol and small molecular sugars.

[0042] The hydrolysis reactor is a circulating flow reactor, and the hydrolysis reactor and the electrocatalytic reactor are flexibly connected.

[0043] The electrocatalytic reactor is used to convert the intermediates generated by the hydrolysis reaction into aromatic hydrocarbons and ketone compounds. The electrocatalytic reactor includes an electrolytic cell, and the anode and cathode in the electrolytic cell are respectively used to generate high-value added chemicals and green hydrogen.

[0044] The catalyst includes a thermal catalyst for the depolymerization of organic solid waste and an electrocatalyst for the high-value catalytic conversion of small molecules after depolymerization.

[0045] The heat recovery system includes a heat exchanger, a heat conduit, and a heat storage device. By recovering the waste heat during the reaction process and introducing it into the reactor, it ensures that the reaction process proceeds stably under low energy consumption conditions, maximizing the energy utilization efficiency. The heat recovery efficiency in the heat recovery system is estimated through a heat conduction model, and the formula is as follows:

[0046] Q rec = α·A·ΔT

[0047] Among them, Q rec is the recovered heat, α is the heat conduction coefficient, A is the heat exchanger area, ΔT is the temperature difference. The heat recovery system includes a heat exchanger, a heat conduit, and a heat storage device. The heat storage device is a phase change material energy storage device.

[0048] The process of the hydrolysis reactor follows a thermal catalytic reaction kinetics model, and the reaction rate of the thermal catalytic reaction kinetics model:

[0049] r hydrolysis = k(T)·C raw

[0050] Among them, r hydrolysis is the hydrolysis reaction rate, is the reaction rate constant related to temperature, A is the pre-exponential factor, E a is the activation energy, R is the gas constant, T is the reaction temperature, and C raw is the raw material concentration.

[0051] The relationship between the current density and voltage in the electrocatalytic reactor follows the Nernst equation, and the reaction rate is described by the Tafel equation. The formula is as follows:

[0052]

[0053] where i is the current density, i 0 is the exchange current density, α is the charge transfer coefficient, n is the number of electron transfers, F is the Faraday constant, E is the electrode potential, and E 0 is the standard electrode potential, R is the gas constant, T is the reaction temperature. The organic solid waste mainly includes lignocellulosic biomass and polyethylene terephthalate. Sodium hydroxide is used as the basic catalyst in the hydrolysis reaction, and the addition amount of the catalyst is 0.5 to 3 wt%. The hydrolysis reactor includes a temperature and pressure control system and a heat gradient reaction device. The temperature and pressure control system includes multiple temperature sensors, pressure sensors, and a real-time feedback control device. The electrocatalyst of the electrocatalytic reactor is based on nickel foam metal and is loaded with inexpensive metals with high catalytic activity suitable for this system.

[0054] An organic solid waste thermoelectric cascade catalytic conversion method includes the following steps:

[0055] a. Mix the waste plastics and lignocellulosic biomass in a preset ratio, then crush them, adjust the particle size to the range suitable for the hydrolysis reaction, and feed the pretreated raw materials into the feed port of the hydrolysis reactor.

[0056] b. Add a preset amount of sodium hydroxide into the hydrolysis reactor, with the addition amount being 0.5 to 3 wt%. Heat the reaction system by solar energy or industrial waste heat, and maintain the temperature and pressure in the reactor within the optimal range by combining the temperature and pressure control system.

[0057] c. Transport the intermediate generated by the hydrolysis reaction to the electrocatalytic reactor, and catalytically generate high-value-added chemicals at the anode and green hydrogen at the cathode by adjusting the current and voltage.

[0058] d. Through the heat exchanger and phase change material energy storage device in the heat recovery system, recover and utilize the waste heat generated during the electrocatalytic reaction and hydrolysis reaction processes, balance the temperature fluctuations in the system, and maintain the stability of the reaction conditions.

[0059] e. After the reaction is completed, the generated high-value-added chemicals and green hydrogen are collected and purified separately. The obtained chemicals can be used in fine chemicals or material preparation, and the green hydrogen can be used as a clean energy source.

[0060] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An organic solid waste thermal power cascade catalytic conversion system, characterized in that: include: Hydrolysis reactors, electrocatalytic reactors, catalysts and heat recovery systems; The hydrolysis reactor converts waste plastics and lignocellulosic biomass into intermediates through a thermal catalytic reaction, wherein the intermediates include ethylene glycol and small molecule sugars; The hydrolysis reactor is a circulating flow reactor; The electrocatalytic reactor is used to convert the intermediates generated by the hydrolysis reaction into aromatic hydrocarbons and ketone compounds; The catalyst includes a thermal catalyst for depolymerization of organic solid waste and an electrocatalyst for catalytic conversion of small molecules to high value after depolymerization; The heat recovery system includes a heat exchanger, a heat pipe and a heat storage device, which recovers the waste heat in the reaction process and introduces it into the reactor to ensure that the reaction process is carried out stably under low energy consumption conditions and maximize energy utilization efficiency; The hydrolysis reactor process follows a thermal catalytic reaction kinetic model, and the reaction rate of the thermal catalytic reaction kinetic model is: r hydrolysis =k(T)·C raw Among them, r hydrolysis is the hydrolysis reaction rate, is the temperature-dependent reaction rate constant, A is the prefactor, and E a is the activation energy, R is the gas constant, T is the reaction temperature, C raw is the raw material concentration; The relationship between current density and voltage in the electrocatalyst follows the Nernst equation, and the reaction rate is described by the Tafel equation, which is: Where i is the current density, i0 is the exchange current density, α is the charge transfer coefficient, n is the number of electron transfers, F is the Faraday constant, E is the electrode potential, E0 is the standard electrode potential, R is the gas constant, and T is the reaction temperature.

2. The organic solid waste thermal power cascade catalytic conversion system according to claim 1 is characterized by: The heat recovery efficiency in the heat recovery system is estimated by a heat conduction model, and the formula is as follows: Q rec =α·A·ΔT Among them, Q rec is the recovered heat, α is the heat transfer coefficient, A is the heat exchanger area, and ΔT is the temperature difference.

3. The organic solid waste thermal power cascade catalytic conversion system according to claim 1 is characterized by: The organic solid waste is mainly lignocellulosic biomass and polyethylene terephthalate. The thermal catalyst in the hydrolysis reaction uses sodium hydroxide or potassium hydroxide as an alkaline catalyst, and the added amount of the catalyst is 0.5 to 3wt%. The hydrolysis reactor includes a temperature and pressure control system and a thermal gradient reaction device. The temperature and pressure control system includes multiple temperature sensors, pressure sensors and a real-time feedback control device.

4. The organic solid waste thermal power cascade catalytic conversion system according to claim 1 is characterized in that: The electrocatalytic reactor includes an electrolytic cell, in which an anode and a cathode are used to generate high-value-added chemicals and green hydrogen, respectively.

5. The method for thermal-electric cascade catalytic conversion of organic solid waste according to claim 1, characterized in that: The hydrolysis reactor and the electrocatalytic reactor are connected flexibly.

6. The method for thermal-electric cascade catalytic conversion of organic solid waste according to claim 1, characterized in that: The heat recovery system comprises a heat exchanger, a heat pipe and a heat storage device, and the heat storage device is a phase change material energy storage device.

7. The method for thermal-electric cascade catalytic conversion of organic solid waste according to claim 1, characterized in that: The electrocatalyst of the electrocatalytic reactor is based on foamed nickel metal and loaded with low-cost metals with high catalytic activity suitable for the system.

8. A method for thermal-electric cascade catalytic conversion of organic solid waste, characterized in that: The following steps are involved: a. Mixing the waste plastic and lignocellulosic biomass in a preset ratio and then crushing them, adjusting the particle size to a range suitable for the hydrolysis reaction, and feeding the pretreated raw materials into the feed port of the hydrolysis reactor; b. Adding a preset amount of sodium hydroxide or potassium hydroxide in a hydrolysis reactor, the addition amount is 0.5 to 3 wt %, heating the reaction system by solar energy or industrial waste heat, and maintaining the temperature and pressure in the reactor in an optimal range in combination with a temperature and pressure control system; c. The intermediates generated by the hydrolysis reaction are transported to the electrocatalytic reactor, and by adjusting the current and voltage, high value-added chemicals are catalytically produced at the anode and green hydrogen is produced at the cathode; d. Through the heat exchanger and phase change material energy storage device in the heat recovery system, the waste heat generated during the electrocatalytic reaction and hydrolysis reaction is recovered and utilized to balance the temperature fluctuations in the system and maintain the stability of the reaction conditions; e. After the reaction is completed, the generated high-value-added chemicals and green hydrogen are collected and purified separately. The obtained chemicals can be used for fine chemicals or material preparation, and green hydrogen can be used as clean energy.

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