System and method for co-processing waste lithium battery by utilizing garbage power generation

Abstract

The invention discloses a system for co-processing waste lithium batteries by using garbage power generation, comprising: a waste lithium battery processing subsystem which at least comprises an electrified shredding device and a pyrolysis device which are arranged in sequence and is used for crushing and pyrolyzing the waste lithium batteries; the waste incineration power generation subsystem comprises an incinerator and a flue gas purification subsystem; and the waste gas conveying pipeline is connected with the waste lithium battery treatment subsystem and a hearth of the incinerator and is used for conveying waste gas generated by the waste lithium battery treatment subsystem to the hearth of the incinerator. According to the system for co-processing the waste lithium battery through waste power generation, standard emission of volatile and pyrolysis waste gas in the waste lithium battery recycling process can be achieved through waste incineration and an attached flue gas treatment system, heat released by waste gas incineration is fed back to a power generation system, energy consumption is reduced, and the investment cost is low. The invention further discloses a method for co-processing the waste lithium battery through garbage power generation.

Description

Technical Field

[0001] This invention belongs to the field of waste lithium battery recycling and processing technology. Specifically, this invention relates to a system and method for co-processing waste lithium batteries using waste-to-energy. Background Technology

[0002] Lithium-ion batteries are essential electronic products and a crucial pillar for the development of emerging technologies such as new energy and electric vehicles. They are widely used in consumer electronics, power systems, and energy storage systems. The large amounts of metal elements and organic matter in spent lithium-ion batteries not only have potential economic value but also pose significant pollution risks. Recycling and disposing of spent lithium-ion batteries can not only eliminate pollution sources but also achieve resource recovery and reuse, including a large number of valuable metal ions and other substances.

[0003] Currently, recycling companies for valuable metals and black powder from spent lithium batteries primarily employ a "physical sorting + pyrolysis purification" process. This involves using charged crushing technology in a nitrogen environment to prevent electrolyte volatilization and potential explosions. High-temperature pyrolysis removes the electrolyte and separator, followed by crushing and sorting to collect black powder, copper, aluminum, and other products. Simultaneously, the waste gas generated during pyrolysis undergoes secondary combustion, acid removal, rapid cooling, and dust removal processes to meet emission standards. Overall, this process is energy-intensive, has high investment costs, and also presents some heat source waste.

[0004] This invention provides a system for co-processing waste lithium batteries using waste-to-energy, specifically how to achieve compliant emissions of volatile and pyrolysis waste gases during the recycling process of waste lithium batteries through waste incineration and its associated flue gas treatment system, thereby reducing energy consumption. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a system for the co-processing of spent lithium batteries using waste-to-energy, with the goal of achieving compliant emissions of volatile and pyrolysis waste gases during the recycling process through waste incineration and its associated flue gas treatment system, thereby reducing energy consumption.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a system for co-processing waste lithium batteries using waste-to-energy, comprising: A waste lithium battery processing subsystem includes at least a charged shredding device and a pyrolysis device arranged in sequence for crushing and pyrolysis of waste lithium batteries. A waste incineration power generation system, comprising an incinerator and a flue gas purification subsystem; and An exhaust gas conveying pipeline connects the waste lithium battery processing subsystem to the furnace chamber of the incinerator, and is used to convey the exhaust gas generated by the waste lithium battery processing subsystem to the furnace chamber of the incinerator.

[0007] The electrified shredder includes at least two shredders connected in series. The electrified shredder is also equipped with an inert gas protection submodule, an oxygen content sensor, a flame sensor, a flow sensor, a temperature sensor, and a pressure sensor.

[0008] The pyrolysis device is a high-temperature pyrolysis furnace, which is equipped with an inert gas protection submodule, and the pyrolysis temperature is controlled at 500-600℃.

[0009] The waste lithium battery processing subsystem also includes a cooling kiln, which is equipped with a water-cooled jacket, through which circulating water is circulated, and the cooling kiln is equipped with an inert gas protection submodule.

[0010] The waste lithium battery treatment subsystem also includes a dust removal device, which is configured to remove dust from the volatile and pyrolysis waste gases. The dust removal device is connected to the waste gas conveying pipeline. The volatile and pyrolysis waste gases include VOCs, phosphoric acid mist, fluorides, and particulate matter.

[0011] The flue gas purification subsystem includes a semi-dry deacidification submodule, a dry deacidification submodule, and an activated carbon adsorption submodule connected in sequence. The semi-dry deacidification submodule is equipped with a calcium hydroxide slurry reaction system.

[0012] The incinerator is equipped with a combustion air system for supplying combustion air into the furnace and controlling the oxygen concentration inside the furnace.

[0013] This invention also provides a method for co-processing waste lithium batteries using waste-to-energy, employing the aforementioned system and including the following steps: S1: Waste lithium batteries are processed through a waste lithium battery processing subsystem, generating volatile and pyrolysis waste gas, and the volatile and pyrolysis waste gas is subjected to dust removal treatment. S2: The exhaust gas after dust removal is introduced into the furnace of the waste incineration subsystem for combustion. The furnace temperature is controlled at 850-1050℃, the O2 concentration is not less than 6%, and the residence time of the flue gas in the furnace is not less than 2s, so that the organic matter and phosphorus-containing compounds in the exhaust gas are converted into CO2, H2O, HF and phosphoric acid mist. S3: The flue gas containing acidic gases generated in step S2 is purified by the flue gas purification subsystem, so that HF ​​and phosphoric acid mist in the flue gas are converted into solid particulate matter and collected, so as to achieve the emission of flue gas in compliance with standards.

[0014] In step S1, the treatment of waste lithium batteries includes shredding, pyrolysis, cooling and crushing and sorting processes, and each process is carried out in a sealed environment. The shredding process is carried out under inert gas protection, and the particle size of the crushed material is no greater than 30mm. The pyrolysis process is carried out under inert gas protection, and the pyrolysis temperature is controlled at 500-600℃, so that the separator, electrolyte and binder in the lithium battery are pyrolyzed, and the positive and negative electrode powders are detached from the copper and aluminum foil. The cooling process is achieved through water-cooled jacket heat exchange, which cools the material to below 60°C, and the cooling process is carried out under the protection of inert gas.

[0015] In step S3, the purification process sequentially includes a semi-dry deacidification process, a dry deacidification process, and an activated carbon adsorption process. The semi-dry deacidification process involves reacting calcium hydroxide slurry with acidic gas.

[0016] This invention utilizes a waste-to-energy system to co-process used lithium batteries. It achieves compliant emissions of volatile and pyrolysis waste gases generated during the recycling process through waste incineration and its associated flue gas treatment system. The heat released from the incineration of waste gases feeds back into the power generation system, improving energy recovery efficiency and reducing energy consumption. It directly reuses existing waste-to-energy incineration and flue gas purification systems, requiring only the addition of waste gas pretreatment and connecting pipelines, eliminating the need for redundant construction of dedicated waste gas treatment equipment. This significantly reduces equipment purchase and installation costs, thereby lowering overall investment costs. Attached Figure Description

[0017] This manual includes the following figures, which illustrate the following: Figure 1 This is a flowchart of the method for co-processing waste lithium batteries using waste-to-energy power generation, as per the present invention. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solutions of the present invention, and to facilitate its implementation.

[0019] In existing technologies, power lithium batteries include lithium iron phosphate batteries. Waste lithium-ion batteries generally consist of five main parts: casing, positive electrode, negative electrode, separator, and electrolyte. Waste lithium iron phosphate batteries are typically packaged in aluminum or iron casings. The main components of waste lithium iron phosphate batteries are detailed in Tables 1 and 2.

[0020] Table 1. List of components of lithium iron phosphate batteries

[0021] Table 2. Summary of Chemical Composition of Lithium Iron Phosphate Batteries

[0022] Waste lithium iron phosphate batteries use lithium iron phosphate as the positive electrode material and graphite as the negative electrode. The positive electrode of the lithium battery is mainly composed of a uniform mixture of positive electrode active material, a small amount of conductive agent, and organic binder (mainly polyvinylidene fluoride PVDF), coated onto an aluminum foil with a thickness of about 20 μm; the negative electrode is mainly composed of a uniform mixture of negative electrode carbon material, a small amount of conductive agent, and binder, coated onto a copper foil with a thickness of about 20 μm. The main components of the positive and negative electrodes of waste lithium iron phosphate batteries are detailed in Table 3.

[0023] Table 3. Overview of positive and negative electrode components of lithium batteries

[0024] The separator is used to separate the positive and negative electrodes inside a lithium battery, and its main material is polypropylene (PP) or polyethylene (PE).

[0025] The positive and negative electrodes are approximately 0.18–0.2 mm thick, separated by a membrane (polypropylene (PP) or polyethylene (PE) microporous membrane) with a thickness of approximately 10 μm. The electrolyte is typically filled with an organic carbonate solution containing lithium hexafluorophosphate as the solute. The physicochemical properties of the main components of the electrolyte are detailed in Table 4.

[0026] Table 4. Summary of Physicochemical Properties of Main Components of Electrolyte

[0027] Organic carbonates mainly include ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (EMC). Among them, ethylene carbonate (EC) and propylene carbonate (PC) are relatively stable and have the highest proportion.

[0028] Lithium hexafluorophosphate (LiPF6) is the most important component of the electrolyte. When exposed to air or heated, LiPF6 decomposes rapidly in the air due to the action of water vapor, releasing PF5 and producing white fumes. Ethylene carbonate (EC) is a transparent, colorless liquid that is a crystalline solid at room temperature. It is an excellent solvent for electrolytes and is not easily volatile. Propylene carbonate (PC) is highly soluble in water and carbon tetrachloride and is not easily volatile. Dimethyl carbonate (DMC) is an important organic synthesis intermediate with excellent solubility and is readily soluble in water. Diethyl carbonate (DEC) is a colorless liquid, insoluble in water, but miscible with organic solvents such as alcohols, ketones, and esters. It is easily volatilized along with these organic solvents during battery disassembly and enters the atmosphere. Ethyl methyl carbonate (EMC) is an excellent solvent for lithium-ion battery electrolytes, but due to its unstable properties, some of it is easily decomposed and volatilized during battery disassembly. The scheme of this application is as follows: In a first aspect, embodiments of the present invention provide a system for co-processing waste lithium batteries using waste-to-energy, comprising: A waste lithium battery processing subsystem includes at least a charged shredding device and a pyrolysis device arranged in sequence for crushing and pyrolysis of waste lithium batteries. The waste incineration power generation system includes an incinerator and a flue gas purification subsystem; and an exhaust gas delivery pipeline that connects the waste lithium battery processing subsystem to the furnace of the incinerator, for delivering the exhaust gas generated by the waste lithium battery processing subsystem to the furnace of the incinerator.

[0029] In this embodiment of the invention, the waste lithium battery recycling production line is located within the production workshop and operates continuously 24 hours a day, with a processing capacity of 36 tons per day and 10,000 tons per year of waste lithium batteries. The waste lithium battery recycling process sequentially includes a charged shredding process, a pyrolysis process, a cooling process, and a crushing and sorting process. Each process is carried out in a sealed negative pressure environment to achieve centralized collection and coordinated treatment of waste gas.

[0030] In this embodiment of the invention, the live-line shredding device includes at least two shredders connected in series. The device is also equipped with an inert gas protection submodule, an oxygen content sensor, a flame sensor, a flow sensor, a temperature sensor, and a pressure sensor. The live-line shredding device is used in the live-line shredding process. In this process, waste lithium batteries are conveyed to a rotary sealed chamber via a feeding conveyor, and then fed into two shredders connected in series. The waste lithium batteries are shredded through a two-stage shredding process. The shredding system adopts a fully sealed structure design, and nitrogen gas is introduced throughout the shredding process for protection. The shredding system is equipped with an oxygen content sensor, an ultraviolet flame sensor, a nitrogen flow sensor, a temperature sensor, and a pressure sensor. Each sensor is connected to the automatic control system, which provides a safety interlock protection function. The material is sheared and shredded using the two-stage shredding blades of the shredder, and the particle size of the shredded product is controlled to be no greater than 30 mm.

[0031] In this embodiment of the invention, the pyrolysis device is a high-temperature pyrolysis furnace, which is equipped with an inert gas protection submodule, and the pyrolysis temperature is controlled at 500-600°C. The high-temperature pyrolysis furnace is used in the pyrolysis process. In this process, the material processed by the shredding process is conveyed into the high-temperature pyrolysis furnace via a fully sealed screw conveyor. The high-temperature pyrolysis furnace is the core equipment of the waste lithium battery resource utilization production line. It maintains a nitrogen protective atmosphere inside, and under high-temperature conditions of 500-600°C, the separator, electrolyte, and binder in the lithium battery undergo a pyrolysis reaction, causing the positive and negative electrode active material powders to detach from the copper and aluminum foil surfaces, laying the foundation for subsequent separation of metal and active material powders.

[0032] The waste lithium battery processing subsystem also includes a cooling kiln, a blade crusher, a shell sorter, and a drum screen. The cooling kiln is equipped with a water-cooled jacket, through which circulating water is circulated, and the cooling kiln is also equipped with an inert gas protection submodule.

[0033] The cooling kiln is used in the cooling process, where materials pyrolyzed in the high-temperature pyrolysis furnace are conveyed to the cooling kiln. The cooling kiln is equipped with a water-cooled jacket, through which circulating cooling water is passed. Through indirect heat exchange between the circulating cooling water and the material, the material temperature is reduced to below 60°C. To prevent oxidation of the metal components in the material, a nitrogen protective atmosphere is maintained throughout the cooling process.

[0034] Blade crushers, shell separators, and drum screens are used in the crushing and sorting process. In this process, the material cooled in the cooling kiln is conveyed to the drum screen via pneumatic conveying equipment, where black powder is removed. The remaining material after screening is temporarily stored in an intermediate silo and then fed into the No. 1 blade crusher for further crushing. The crushed material then enters a square gyratory screen for secondary screening. The material after removing black powder is conveyed to the shell separator for further sorting. The separated shell mixture is collected in ton bags and subsequently separated into aluminum shells and copper electrodes by an offline color sorter. The remaining material after shell sorting is fed into the No. 2 blade crusher for deep crushing. After crushing, the material is screened again to remove black powder and then fed into a cyclone mill for fine grinding. The ground material is conveyed to a classifier, where black powder is separated. The remaining material after classification enters a four-layer circular gyratory screen for multi-stage screening. The oversize material from the first screen and the undersize material from the fourth screen are collected in ton bags. The oversize material from the second screen is returned to the cyclone mill for further grinding. The oversize material from the third screen and the oversize material from the fourth screen are sent to the No. 1 and No. 2 gravity separators, respectively, to separate copper from aluminum.

[0035] In this embodiment of the invention, the waste lithium battery treatment subsystem further includes a dust removal device, which is configured to remove dust from the volatile and pyrolysis waste gases. The dust removal device is connected to a waste gas conveying pipeline, and the waste gas after dust removal is conveyed to the incinerator through the waste gas conveying pipeline. The volatile and pyrolysis waste gases include VOCs, phosphoric acid mist, fluorides, and particulate matter. The main polluting processes and waste gases are detailed in Table 5.

[0036] Table 5 Major Polluting Processes and Waste Gases

[0037] In this embodiment of the invention, the flue gas purification subsystem includes a semi-dry deacidification submodule, a dry deacidification submodule, and an activated carbon adsorption submodule connected in sequence. The semi-dry deacidification submodule is equipped with a calcium hydroxide slurry reaction system.

[0038] In this embodiment of the invention, the incinerator is equipped with a combustion air system for supplying combustion air into the furnace and controlling the oxygen concentration inside the furnace.

[0039] In the waste-to-energy incineration system, municipal solid waste is fed into the incinerator furnace through the inlet and ignited by an igniter to achieve self-sustaining combustion. Combustion air is blown into the furnace through a combustion air system, which consists of a primary air fan, a secondary air fan, a primary air preheater, and ductwork. This system provides the necessary oxygen for combustion to ensure complete combustion. The system can dynamically adjust the air intake based on changes in the properties of the municipal solid waste and the CO detection value at the chimney outlet to ensure stable operation during the incineration process.

[0040] The flue gas generated from municipal solid waste incineration mainly contains four categories of pollutants: particulate matter (dust), acidic gases (such as HCl, SOx, NOx, etc.), heavy metals (such as Hg, Pb, Cr, etc.), and highly toxic organic pollutants (such as dioxins, etc.). This system employs a combined process of "SNCR denitrification + semi-dry reaction tower deacidification + dry powder injection deacidification + activated carbon injection adsorption + bag filter dust removal" to purify the incineration flue gas. This purification system mainly consists of a lime slurry preparation system, a semi-dry reaction tower system, a bag filter system, an activated carbon injection system, and an ash conveying system.

[0041] The removal of acidic gases is centered around a semi-dry reaction tower system. Its working principle is as follows: Incineration flue gas enters from the top of the semi-dry reaction tower, is evenly distributed by an airflow distribution plate at the top, and then flows downwards. Inside the reaction tower, below the airflow distribution plate, is an atomizer. The high-speed rotating atomizer atomizes the lime slurry into tiny droplets, with the droplet spray direction perpendicular to the flue gas flow direction. As the lime slurry droplets flow downwards with the flue gas, they exchange heat with the high-temperature flue gas and evaporate simultaneously, while also undergoing acid-base neutralization reactions with acidic gases (such as HCl and SO2) in the flue gas. The resulting solid particles enter the subsequent dust collector along with the flue gas, while larger solid particles not carried by the flue gas settle into the ash hopper at the bottom of the reaction tower. The ash hopper is equipped with an anti-clogging crusher and a rotary ash discharge valve. Particles discharged from the rotary ash discharge valve are transported by a chain conveyor to the ash storage bin.

[0042] To further improve the removal efficiency of acidic substances, a dry acid removal system is added after the semi-dry acid removal system. Dry slaked lime powder is sprayed directly into the flue between the semi-dry reaction tower and the bag filter through nozzles, where it continues to react with unreacted acidic substances in the flue gas. Simultaneously, activated carbon is sprayed into this flue to utilize its adsorption properties to remove heavy metals and organic pollutants (including dioxins) from the flue gas.

[0043] After the waste lithium battery treatment subsystem delivers the exhaust gas into the waste incineration furnace, it stays at a high temperature of 850℃ for 2-3 seconds. The organic matter, non-condensable gases and electrolyte components in the exhaust gas are completely burned and decomposed in the flame zone, ultimately generating CO2, H2O, HF and phosphoric acid mist. The heat released during the combustion process is integrated into the thermal energy cycle of the waste incineration system, which can increase the power generation of the power generation system.

[0044] The HF and phosphoric acid mist in the combustion products enter the semi-dry desulfurization system and the dry desulfurization system with the incineration flue gas, and undergo a full neutralization reaction with lime slurry and hydrated lime powder to generate calcium fluoride and calcium phosphate solid particles. These solid particles are collected during the subsequent dust removal process of the bag filter. At the same time, the activated carbon injection system can adsorb the residual VOCs in the flue gas, further reducing the VOCs emission concentration.

[0045] Secondly, embodiments of the present invention also provide a method for co-processing waste lithium batteries using waste-to-energy, employing a system and including the following steps: S1: Waste lithium batteries are processed through the waste lithium battery treatment subsystem, generating volatile and pyrolysis waste gas, and dust removal treatment is performed on the volatile and pyrolysis waste gas. S2: The exhaust gas after dust removal is introduced into the furnace of the waste incineration subsystem for combustion. The furnace temperature is controlled at 850-1050℃, the O2 concentration is not less than 6%, and the residence time of the flue gas in the furnace is not less than 2s, so that the organic matter and phosphorus-containing compounds in the exhaust gas are converted into CO2, H2O, HF and phosphoric acid mist. S3: The flue gas containing acidic gases generated in step S2 is purified by the flue gas purification subsystem, so that HF ​​and phosphoric acid mist in the flue gas are converted into solid particulate matter and collected, so as to achieve the emission of flue gas in compliance with standards.

[0046] In step S1, the processing of waste lithium batteries includes shredding, pyrolysis, cooling and crushing and sorting processes, all of which are carried out in a sealed environment. Among them, the live shredding process is carried out under inert gas protection, and the particle size of the crushed material is no more than 30mm; The pyrolysis process is carried out under inert gas protection, and the pyrolysis temperature is controlled at 500-600℃, which causes the separator, electrolyte and binder in the lithium battery to pyrolyze, and the positive and negative electrode powders fall off the copper and aluminum foil. The cooling process is achieved through water-cooled jacket heat exchange, which cools the material to below 60°C, and the cooling process is carried out under the protection of inert gas.

[0047] In the live-line shredding process, waste lithium batteries are conveyed to a rotary sealed silo via a feeding conveyor, and then fed into two shredders connected in series. The waste lithium batteries are shredded through a two-stage shredding process. The shredding system adopts a fully sealed structure design, with nitrogen gas supplied throughout the shredding process for protection. The system is equipped with oxygen content sensors, ultraviolet flame sensors, nitrogen flow sensors, temperature sensors, and pressure sensors. Each sensor is connected to the automatic control system, which provides a safety interlock protection function. The two-stage shredding blades of the shredders shear and crush the material, controlling the particle size of the shredded product to no more than 30mm.

[0048] In the live shredding process, the shredder shreds the waste lithium batteries under a nitrogen protective atmosphere. The exhaust gas generated in this process mainly consists of electrolyte volatilization gas and nitrogen.

[0049] In the pyrolysis process, the material after shredding is conveyed to the high-temperature pyrolysis furnace via a fully sealed screw conveyor. The high-temperature pyrolysis furnace is the core equipment of the waste lithium battery resource utilization production line. It maintains a nitrogen protective atmosphere inside and, under high temperature conditions of 500℃~600℃, causes the separator, electrolyte, and binder in the lithium battery to undergo a pyrolysis reaction. This causes the positive and negative electrode active material powders to detach from the copper and aluminum foil surfaces, laying the foundation for the subsequent separation of metals and active material powders.

[0050] In the cooling process, the material after pyrolysis in the high-temperature pyrolysis furnace is conveyed to the cooling kiln. The cooling kiln is equipped with a water-cooled jacket, through which circulating cooling water is circulated. Through indirect heat exchange between the circulating cooling water and the material, the material temperature is reduced to below 60°C. To prevent oxidation of the metal components in the material, a nitrogen protective atmosphere is maintained throughout the cooling process.

[0051] In the crushing and sorting process, the material cooled in the cooling kiln is conveyed to a drum screen via pneumatic conveying equipment to remove black powder. The remaining material after screening is temporarily stored in an intermediate silo and then fed into the No. 1 blade crusher for further crushing. The crushed material then enters a square gyratory screen for secondary screening. The material after removing black powder is conveyed to an outer shell separator for further separation. The separated outer shell mixture is collected in ton bags and subsequently separated into aluminum outer shells and copper electrode columns by an offline color sorter. The remaining material after outer shell separation is fed into the No. 2 blade crusher for deep crushing. The crushed material is then screened again to remove black powder before entering a cyclone mill for fine grinding. The ground material is conveyed to a classifier, where black powder is separated. The remaining material after classification enters a four-layer circular gyratory screen for multi-stage screening. The oversize material from the first screen and the undersize material from the fourth screen are collected in ton bags. The oversize material from the second screen is returned to the cyclone mill for further grinding. The oversize material from the third screen and the oversize material from the fourth screen are sent to the No. 1 and No. 2 gravity separators, respectively, to separate copper from aluminum.

[0052] In this embodiment of the invention, the temperature of the pyrolysis process of the waste lithium battery electrolyte is controlled between 500℃ and 600℃. According to relevant data, aluminum has a melting point of 660℃ and a boiling point of 2327℃, while copper has a melting point of 1083.4℃ and a boiling point of 2567℃. Since the pyrolysis temperature is lower than the melting points of aluminum and copper, no volatilization of aluminum or copper metals will occur during the pyrolysis process. Because none of the components of a lithium battery contain chlorine, no dioxin-like pollutants will be generated under the above pyrolysis conditions. The main pollutants in the pyrolysis exhaust gas are VOCs (calculated as non-methane total hydrocarbons), phosphoric acid mist, and fluorides. Furthermore, the entire process of shredding, pyrolysis, cooling, and crushing and sorting of waste lithium batteries is completed in a sealed, slightly negative pressure environment, effectively preventing the emission of fugitive gases.

[0053] In the pyrolysis process, the crushed battery material is subjected to high-temperature pyrolysis in a nitrogen atmosphere in a high-temperature pyrolysis furnace, wherein the oxygen content of the nitrogen atmosphere is controlled to be below 2%.

[0054] The electrolyte is an organic carbonate electrolyte using lithium hexafluorophosphate as the electrolyte. The organic carbonates mainly include ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (EMC). Lithium hexafluorophosphate completely decomposes at 550℃ into lithium fluoride (solid) and phosphorus pentafluoride (gaseous). Phosphorus pentafluoride is unstable and readily reacts with water vapor in the waste gas to form phosphoric acid and fluorides. The organic carbonates in the electrolyte (characterized as CxHyOz(S)) evaporate into gaseous CxHyOz(g) under low-oxygen conditions and enter the waste gas. The main reaction process is as follows: ;

[0055] Based on relevant data on the dismantling of waste lithium batteries: the separator accounts for 4% of the mass of the battery; the electrolyte accounts for 10% of the mass, and organic compounds account for approximately 90% of the mass of the electrolyte. Therefore, it is estimated that when processing 10,000 tons of waste lithium batteries annually, the total amount of VOCs requiring co-processing in a waste incineration system is 1300 tons per year. According to data on the dismantling of waste lithium batteries, the electrolyte (mainly lithium hexafluorophosphate) accounts for 10% of the mass of the electrolyte. Based on this calculation, when the annual processing scale is 10,000 tons of waste lithium batteries, the total amount of lithium hexafluorophosphate in the electrolyte is 100 tons / year, corresponding to a total amount of phosphorus pentafluoride that needs to be co-processed in the waste incineration system of 82.9 tons / year. Furthermore, according to relevant data on the dismantling of waste lithium batteries, the mass percentage of fluorine in the batteries is 1.3%. During the pyrolysis process, the fluorine in the batteries enters the waste gas in the form of gaseous fluorides. Based on this calculation, when the annual processing scale is 10,000 tons of waste lithium batteries, the amount of fluorides (calculated as hydrogen fluoride) generated in the waste gas is approximately 136.8 tons per year.

[0056] In step S2 above, the waste gas from the waste lithium battery treatment system enters the waste incineration furnace and is maintained at a high temperature of 850 degrees Celsius for 2-3 seconds. During this process, the organic waste gas, non-condensable gases, and electrolyte in the waste gas are completely combusted within the flame zone, ultimately decomposing into CO2, H2O, HF, and phosphoric acid mist. This process releases heat, increasing the power generation capacity of the power generation system. The organic matter in the waste gas is organic carbonate, and the phosphorus-containing compound is phosphorus pentafluoride.

[0057] In step S3 above, the purification process includes semi-dry deacidification, dry deacidification and activated carbon adsorption processes in sequence. The semi-dry deacidification process uses calcium hydroxide slurry to react with acidic gas.

[0058] In summary, in this embodiment of the invention, the waste lithium battery processing workshop generates waste gas during the charged crushing and pyrolysis processes. After dust removal, the gas is transported to the furnace in the waste ventilation workshop for incineration. Under conditions where the furnace temperature is between 850 and 1050°C, the O2 concentration is above 6%, and the flue gas residence time in the combustion chamber is above 2 seconds, the organic matter and phosphorus pentafluoride in the waste gas are ultimately converted into CO2, H2O, HF, and phosphoric acid mist. These acidic gases fully react with calcium hydroxide slurry in a semi-dry deacidification tower to produce calcium chloride and calcium phosphate, which are collected in the form of fly ash. A small amount of HF, phosphoric acid mist, and gaseous organic matter that may not have had time to react can be reacted and adsorbed by the downstream dry deacidification system and activated carbon adsorption system, and enter the fly ash in the form of particulate matter. Finally, the compliant emission of volatile and pyrolysis waste gases during the waste lithium battery recycling process is achieved through waste incineration and its associated flue gas treatment system.

[0059] The system and method for co-processing waste lithium batteries using waste-to-energy in this embodiment of the invention have the following effects: The temperature of the waste incinerator is strictly controlled between 850 and 1050℃, the O2 concentration is above 6%, and the residence time of flue gas in the combustion chamber is above 2 seconds to ensure that the outlet furnace temperature is not lower than 850℃, thereby enabling the VOCs in the waste gas to be fully decomposed.

[0060] The main pollutants in waste incineration flue gas include acidic gases, particulate matter (dust), heavy metals, incomplete combustion products (CO), and highly toxic organic pollutants.

[0061] To address pollutants in incinerator flue gas, waste-to-energy plants employ a treatment process of "SNCR + semi-dry reaction tower + activated carbon injector + dry powder injection + bag filter" to treat the pollutants before discharging them through a chimney.

[0062] This treatment process is the best feasible technology and meets the relevant requirements of the "Technical Standard for Municipal Solid Waste Incineration and Energy Utilization Engineering" (GB / T 51452-2024). According to the survey results of similar projects in the engineering analysis, the process adopted is basically the same. The dust removal efficiency of the flue gas purification system is ≥99.8%, the desulfurization efficiency is ≥90%, the denitrification efficiency is ≥40%, the dechlorination efficiency is ≥60%, the removal efficiency of heavy metals Hg, Cd, and Pb is ≥90%, the removal efficiency of highly toxic organic pollutants is ≥98%, and the removal efficiency of acidic gases such as HCl is above 95%.

[0063] After treatment, the flue gas emissions can stably meet the requirements of the "Standard for Pollution Control of Municipal Solid Waste Incineration" (GB18485-2014).

[0064] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A system for co-processing waste lithium batteries using waste-to-energy, characterized in that, include: A waste lithium battery processing subsystem includes at least a charged shredding device and a pyrolysis device arranged in sequence for crushing and pyrolysis of waste lithium batteries. A waste incineration power generation system includes an incinerator and a flue gas purification subsystem; and an exhaust gas conveying pipeline connecting the waste lithium battery processing subsystem to the furnace of the incinerator, for conveying the exhaust gas generated by the waste lithium battery processing subsystem to the furnace of the incinerator.

2. The system according to claim 1, characterized in that, The electrified shredder includes at least two shredders connected in series. The electrified shredder is also equipped with an inert gas protection submodule, an oxygen content sensor, a flame sensor, a flow sensor, a temperature sensor, and a pressure sensor.

3. The system according to claim 1, characterized in that, The pyrolysis device is a high-temperature pyrolysis furnace, which is equipped with an inert gas protection submodule, and the pyrolysis temperature is controlled at 500-600℃.

4. The system according to any one of claims 1 to 3, characterized in that, The waste lithium battery processing subsystem also includes a cooling kiln, which is equipped with a water-cooled jacket, through which circulating water is circulated, and the cooling kiln is equipped with an inert gas protection submodule.

5. The system according to any one of claims 1 to 3, characterized in that, The waste lithium battery treatment subsystem also includes a dust removal device, which is configured to remove dust from the volatile and pyrolysis waste gases. The dust removal device is connected to the waste gas conveying pipeline. The volatile and pyrolysis waste gases include VOCs, phosphoric acid mist, fluorides, and particulate matter.

6. The system according to any one of claims 1 to 3, characterized in that, The flue gas purification subsystem includes a semi-dry deacidification submodule, a dry deacidification submodule, and an activated carbon adsorption submodule connected in sequence. The semi-dry deacidification submodule is equipped with a calcium hydroxide slurry reaction system.

7. The system according to any one of claims 1 to 3, characterized in that, The incinerator is equipped with a combustion air system for supplying combustion air into the furnace and controlling the oxygen concentration inside the furnace.

8. A method for co-processing waste lithium batteries using waste-to-energy power generation, characterized in that, The system described in any one of claims 1 to 7 is used, and includes the following steps: S1: Waste lithium batteries are processed through a waste lithium battery processing subsystem, generating volatile and pyrolysis waste gas, and the volatile and pyrolysis waste gas is subjected to dust removal treatment. S2: The exhaust gas after dust removal is introduced into the furnace of the waste incineration subsystem for combustion, and the temperature in the furnace is controlled at 850-1050℃, the O2 concentration is not less than 6%, and the residence time of the flue gas in the furnace is not less than 2s. S3: The flue gas containing acidic gases generated in step S2 is purified by the flue gas purification subsystem, so that HF ​​and phosphoric acid mist in the flue gas are converted into solid particulate matter and collected, so as to achieve the emission of flue gas in compliance with standards.

9. The method according to claim 8, characterized in that, In step S1, the treatment of waste lithium batteries includes shredding, pyrolysis, cooling and crushing and sorting processes, and each process is carried out in a sealed environment. The shredding process is carried out under inert gas protection, and the particle size of the crushed material is no greater than 30mm. The pyrolysis process is carried out under inert gas protection, and the pyrolysis temperature is controlled at 500-600℃, so that the separator, electrolyte and binder in the lithium battery are pyrolyzed, and the positive and negative electrode powders are detached from the copper and aluminum foil. The cooling process is achieved through water-cooled jacket heat exchange, which cools the material to below 60°C, and the cooling process is carried out under the protection of inert gas.

10. The method according to claim 8, characterized in that, In step S3, the purification process sequentially includes a semi-dry deacidification process, a dry deacidification process, and an activated carbon adsorption process. The semi-dry deacidification process involves reacting calcium hydroxide slurry with acidic gas.

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