Polyurethane recycling device and method

Abstract

The invention discloses a polyurethane recycling device and method. The method comprises the following steps: crushing polyurethane to obtain a polyurethane crushed material; carrying out anaerobic pyrolysis on the crushed polyurethane material to obtain pyrolysis gas and pyrolysis carbon; combustible gas and pyrolytic carbon in the pyrolysis gas are fed into an incinerator for resource utilization, and non-combustible gas NH3 in the pyrolysis gas is fed into the incinerator for denitration reaction. According to the invention, the degradation of polyurethane components is realized by utilizing the high-temperature hot ash of the incinerator, and the energy utilization and denitration resource utilization of the degraded components are respectively realized, so that the utilization value level of nitrogen-containing and hydrocarbon-containing components of polyurethane is improved.

Description

Technical Field

[0001] This invention relates to the field of polyurethane (PU) recycling technology, and more particularly to a polyurethane recycling device and method. Background Technology

[0002] The geometric transformation process of polyurethane foam materials results in waste generation, which can reach up to 20% under certain conditions. A portion of this flexible polyurethane foam waste can be reused as resilient foam filling material for pillows, sofas, mattresses, and other items, or it can be converted into other end products. Rigid polyurethane foam materials have excellent performance and wide applications, and their development is rapidly increasing. Therefore, recycling its waste products can effectively protect the environment and reduce pollution.

[0003] However, a considerable amount of polyurethane foam is still being directly landfilled, wasting resources and causing serious environmental pollution. Currently, most PU waste is disposed of through landfilling and incineration, or shredded into low-value fibers for carpets, resulting in enormous resource waste. Therefore, developing reprocessing methods to recycle PU waste is crucial for the sustainable use of resources. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention provide a polyurethane recycling device and method.

[0006] In a first aspect, the present invention proposes a method for recycling polyurethane, comprising the following steps:

[0007] (1) The polyurethane is crushed to obtain polyurethane fragments;

[0008] (2) The polyurethane fragments are subjected to anaerobic pyrolysis to obtain pyrolysis gas and pyrolysis carbon;

[0009] (3) The combustible gas in the pyrolysis gas and the pyrolysis char are sent to the incinerator for resource utilization, and the non-combustible gas NH3 in the pyrolysis gas is sent to the incinerator for denitrification reaction.

[0010] Furthermore, the particle size of the polyurethane fragments is less than 2 cm.

[0011] In a second aspect, the present invention provides a polyurethane recycling apparatus for implementing the polyurethane recycling method proposed in the first aspect, comprising:

[0012] Fluidized bed incinerator;

[0013] A cyclone separator cone, wherein the outlet end of the fluidized bed incinerator is connected to the inlet end of the cyclone separator cone;

[0014] A return valve is provided at the bottom of the cyclone separator cone;

[0015] A polyurethane storage silo is provided for storing polyurethane scraps, and a closed feeder is provided between the polyurethane storage silo and the return valve.

[0016] Furthermore, the high-temperature flue gas generated by the fluidized bed incinerator enters the cyclone separator cone and is separated into high-temperature gas and high-temperature hot ash. The high-temperature hot ash enters the return valve, and the high-temperature gas is discharged after heat utilization.

[0017] Furthermore, the polyurethane fragments are conveyed to the return valve via the closed feeder to undergo an anaerobic pyrolysis reaction to release pyrolysis gas and pyrolysis carbon.

[0018] Furthermore, the pyrolysis gas and the pyrolysis char are returned to the fluidized bed incinerator along with the high-temperature hot ash.

[0019] Furthermore, the pyrolysis gas includes CO, CO2, H2, NH3, and low-carbon hydrocarbon gases of C1 to C4.

[0020] Furthermore, the temperature of the high-temperature hot ash is 800–950°C.

[0021] Furthermore, the fluidized bed incinerator is used for incineration power generation.

[0022] Furthermore, the fluidized bed incinerator includes one of a circulating fluidized bed incinerator, a bubbling fluidized bed incinerator, and a dual-bed fluidized bed incinerator.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention utilizes the high-temperature hot ash of an incinerator to degrade polyurethane components, and enables energy utilization and denitrification resource utilization of the degraded components, thereby improving the utilization value of nitrogen-containing and hydrocarbon-containing components of polyurethane. Attached Figure Description

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 This is a flowchart of the polyurethane recycling method of the present invention;

[0027] Figure 2 This is a schematic diagram of the polyurethane recycling device of the present invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Polyurethane storage silo; 2. Enclosed feeder; 3. Return valve; 4. Fluidized bed incinerator; 5. Cyclone separator cone. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] The following description, in conjunction with the accompanying drawings, describes the polyurethane recycling apparatus and method proposed in this invention.

[0032] like Figure 1 As shown, the polyurethane recycling method of the present invention includes the following steps:

[0033] (1) The polyurethane is crushed to obtain polyurethane fragments;

[0034] (2) The polyurethane fragments are subjected to anaerobic pyrolysis to obtain pyrolysis gas and pyrolysis carbon;

[0035] (3) The combustible gas in the pyrolysis gas and the pyrolysis char are sent to the incinerator for resource utilization, and the non-combustible gas NH3 in the pyrolysis gas is sent to the incinerator for denitrification reaction.

[0036] Step (1) involves the crushing process of waste polyurethane foam material. In some embodiments, a shear crusher can be used to shear and crush the waste polyurethane foam material to obtain polyurethane fragments. In some embodiments, the particle size of the polyurethane fragments is less than 2 cm.

[0037] Step (2) is the anaerobic pyrolysis process of polyurethane. Under anaerobic conditions, polyurethane fragments are pyrolyzed to obtain pyrolysis gas and pyrolysis char. The temperature of anaerobic pyrolysis of polyurethane is 750-900℃. The pyrolysis gas includes CO, CO2, H2, NH3, and low-carbon hydrocarbon gases of C1-C4, including CH4, C2H6, C2H4, C3H6, C4H8, etc.

[0038] This invention involves pyrolyzing polyurethane under anaerobic conditions. Compared with pyrolysis under aerobic conditions, anaerobic pyrolysis ensures that no NOx is generated in the pyrolysis products, and the pyrolysis gas produced has a higher calorific value.

[0039] Step (3) is the subsequent utilization process of pyrolysis gas and pyrolysis char. The combustible gas in the pyrolysis gas and the pyrolysis char are sent to the incinerator for combustion to realize resource utilization. The combustible gas includes CO, H2 and low-carbon hydrocarbon gases of C1 to C4. The non-combustible gas NH3 in the pyrolysis gas is sent to the incinerator for denitrification reaction.

[0040] The polyurethane recycling device of the present invention, such as Figure 2 As shown, it includes a fluidized bed incinerator 4, a cyclone separator cone 5, a return valve 3, a polyurethane storage silo 1, and a closed feeder 2.

[0041] The fluidized bed incinerator 4 is used for burning coal or waste to generate electricity. The fluidized bed incinerator 4 includes one of a circulating fluidized bed incinerator, a bubbling fluidized bed incinerator, and a dual-bed fluidized bed incinerator.

[0042] Bubbling fluidized bed incinerators, also known as bubbling bed boilers or fluidized bed boilers, are combustion devices that utilize bubbling fluidized bed combustion technology. The lower part of the furnace is a dense phase zone with a high particle concentration. The static material layer height is typically 0.5–0.7 m, and a bubbling fluidized state is achieved using a split-bed air distribution plate and air cap device. This boiler often has buried tube heating surfaces in the dense phase zone to absorb combustion heat. It is suitable for low-calorific-value fuels with a maximum water content of 65%. Its technical characteristics include low-temperature combustion reducing nitrogen oxide emissions, no need for fuel pretreatment, and rapid load change capability. Compared to circulating fluidized bed incinerators, bubbling fluidized bed incinerators remain economical for boilers with capacities below 35 t / h, although their combustion efficiency is relatively lower, but they require less furnace height.

[0043] The circulating fluidized bed incinerator is a device developed based on fluidized bed combustion technology. It forms a material circulation loop by improving the bubbling fluidized bed, and has the characteristics of strong fuel adaptability and high fluidization speed.

[0044] Cyclone separators are devices used for separating gas-solid or liquid-solid systems. Their working principle relies on the rotational motion caused by the tangential introduction of airflow, which throws solid particles or liquid droplets with significant inertial centrifugal force against the outer wall, causing them to separate. The main characteristics of cyclone separators are simple structure, high operational flexibility, high efficiency, convenient management and maintenance, and low cost. They are used to capture dust particles with diameters of 5–10 μm or larger, and are particularly suitable for coarse dust particles, high dust concentrations, and high temperature and pressure conditions. They are also commonly used as internal separation devices in fluidized bed reactors or as pre-separators, making them a widely used separation device in industry.

[0045] The main function of a return valve is to control and regulate the recirculation of solid materials (such as powders and granules). It is typically installed at the bottom of a separator (such as a cyclone separator) and is responsible for stably and controllably returning the collected solid materials to the main flow of the system (usually a reactor). There are two main types of return valves: non-mechanical and mechanical. This invention uses a non-mechanical return valve.

[0046] The outlet end of the fluidized bed incinerator 4 is connected to the inlet end of the cyclone separator 5. The high-temperature flue gas generated during the combustion process of the fluidized bed incinerator 4 flows out through the outlet end of the fluidized bed incinerator 4 and enters the cyclone separator 5 through the inlet end of the cyclone separator 5.

[0047] The high-temperature flue gas generated by the fluidized bed incinerator 4 enters the cyclone separator 5 and is separated into high-temperature gas and high-temperature hot ash. The high-temperature hot ash descends to the bottom of the cyclone separator 5 and enters the return valve 3 located at the bottom of the cyclone separator 5 through the bottom outlet of the cyclone separator 5. The high-temperature gas is discharged after heat utilization, wherein heat utilization can be achieved through a heat exchange process.

[0048] In addition, the temperature of the high-temperature hot ash is 800-950°C, which meets the pyrolysis requirements of polyurethane.

[0049] A closed feeder is a device that transports bulk solid materials (powder, granules, flakes, lumps, etc.) from one location (usually a silo or storage tank) to another location quantitatively, continuously, or intermittently within a sealed, airtight system. Closed feeders offer sealing, controllability, and conveying capability, preventing material leakage into the environment and preventing air and moisture from entering the material system. They allow for precise control of the feeding speed and flow rate, ensuring stable and reliable material transport.

[0050] Polyurethane scrap is stored in a polyurethane storage silo 1, and a closed feeder 2 is installed between the polyurethane storage silo 1 and the return valve 3. The polyurethane scrap is conveyed to the return valve 3 via the closed feeder 2 to undergo an anaerobic pyrolysis reaction, releasing pyrolysis gas and pyrolysis char. The pyrolysis gas includes CO, CO2, H2, NH3, and low-carbon hydrocarbon gases of C1 to C4.

[0051] The outlet end of the return valve 3 is connected to the inlet end of the fluidized bed incinerator 4, and the pyrolysis gas and the pyrolysis char are returned to the fluidized bed incinerator 4 along with the high-temperature hot ash.

[0052] The combustible gases in the pyrolysis gas and the pyrolysis char are fed into the fluidized bed incinerator 4 for combustion to realize resource utilization. The combustible gases include CO, H2 and low-carbon hydrocarbon gases of C1 to C4. The non-combustible gas NH3 in the pyrolysis gas is fed into the incinerator as a denitrification agent and reacts with the flue gas in the fluidized bed incinerator 4 to undergo a denitrification reaction.

[0053] This invention utilizes the high-temperature hot ash from an incinerator to degrade polyurethane components, and separately utilizes the degraded components for energy and denitrification resource recovery, thereby enhancing the utilization value of nitrogen- and hydrocarbon-containing components in polyurethane.

[0054] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms may refer to different embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0056] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for recycling polyurethane, characterized in that, Includes the following steps: (1) The polyurethane is crushed to obtain polyurethane fragments; (2) The polyurethane fragments are subjected to anaerobic pyrolysis to obtain pyrolysis gas and pyrolysis carbon; (3) The combustible gas in the pyrolysis gas and the pyrolysis char are sent to the incinerator for resource utilization, and the non-combustible gas NH3 in the pyrolysis gas is sent to the incinerator for denitrification reaction.

2. The polyurethane recycling method as described in claim 1, characterized in that, The particle size of the polyurethane fragments is less than 2 cm.

3. A polyurethane recycling device, characterized in that, The method for implementing the polyurethane recycling method according to claim 1 or 2 includes: Fluidized bed incinerator; A cyclone separator cone, wherein the outlet end of the fluidized bed incinerator is connected to the inlet end of the cyclone separator cone; A return valve is provided at the bottom of the cyclone separator cone; A polyurethane storage silo is provided for storing polyurethane scraps, and a closed feeder is provided between the polyurethane storage silo and the return valve.

4. The polyurethane recycling device as described in claim 3, characterized in that, The high-temperature flue gas generated by the fluidized bed incinerator enters the cyclone separator cone and is separated into high-temperature gas and high-temperature hot ash. The high-temperature hot ash enters the return valve, and the high-temperature gas is discharged after heat utilization.

5. The polyurethane recycling device as described in claim 4, characterized in that, The polyurethane fragments are conveyed to the return valve via the closed feeder to undergo an anaerobic pyrolysis reaction, releasing pyrolysis gas and pyrolysis carbon.

6. The polyurethane recycling device as described in claim 5, characterized in that, The pyrolysis gas and the pyrolysis char are returned to the fluidized bed incinerator along with the high-temperature hot ash.

7. The polyurethane recycling device as described in claim 5, characterized in that, The pyrolysis gas includes CO, CO2, H2, NH3, and low-carbon hydrocarbon gases of C1 to C4.

8. The polyurethane recycling device as described in claim 4, characterized in that, The temperature of the high-temperature hot ash is 800–950°C.

9. The polyurethane recycling device as described in claim 2, characterized in that, The fluidized bed incinerator is used for incineration power generation.

10. The polyurethane recycling device as described in claim 2, characterized in that, The fluidized bed incinerator includes one of the following: circulating fluidized bed incinerator, bubbling fluidized bed incinerator, and dual-bed fluidized bed incinerator.

Images