Tail gas treatment device for waste lithium battery recovery

Abstract

The utility model discloses a tail gas treatment device for recycling waste lithium batteries, which comprises a low-temperature volatilization furnace communicated with an inert gas source, and a low-temperature volatilization furnace tail gas outlet, a gas dust removal mechanism, a condenser, a high-temperature incinerator and a centrifugal fan gas inlet which are sequentially communicated through a plurality of sections of tail gas pipelines, the gas dust removal mechanism can be of a structure combining a gravity dust removal settling box and a bag-type dust remover. The dust removal mechanism is arranged between the tail gas outlet of the low-temperature volatilization furnace and the condenser, impurities such as positive and negative electrode dust in electrolyte tail gas can be removed, a tail gas pipeline is effectively prevented from being blocked by the dust and the impurities, the subsequent condenser can be effectively prevented from being polluted by the dust and the impurities, the purity of recycled electrolyte is improved, and the service life of the electrolyte is prolonged. And meanwhile, the working reliability of the low-temperature volatilization furnace is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of waste lithium battery recycling, in particular to a tail gas treatment device for recycling waste lithium batteries. Background Art

[0002] Waste lithium-ion batteries primarily consist of aluminum casings, plastic components, electrolyte, positive and negative electrodes, and separators. To fully recycle waste lithium batteries, crushing, low-temperature volatilization, sorting, high-temperature pyrolysis, and screening are typically employed. During the recycling of waste lithium-ion batteries, multiple steps generate toxic exhaust gases, each with varying composition. Therefore, appropriate treatment methods should be employed for each step to minimize their harmful environmental impact.

[0003] An existing Chinese patent, CN114534435A, discloses a method for treating exhaust gas during the recycling of used lithium batteries. The method defines the exhaust gas generated during the crushing, low-temperature volatilization, and sorting stages as the first exhaust gas. The first exhaust gas is collected via an exhaust pipe and fed to a first exhaust gas collection mechanism using an inert gas as a carrier gas. The first exhaust gas is then condensed through a condensation mechanism to produce an organic solvent. The remaining gas after condensation is defined as the second exhaust gas, which is then treated as waste gas. However, during the low-temperature volatilization stage, in addition to a large amount of organic solvent gas, a large amount of positive and negative electrode material dust is also produced. This dust also enters the exhaust pipe and condensation mechanism along with the carrier gas. Over time, the exhaust pipe will inevitably become clogged, and the condensation mechanism will also be contaminated by the positive and negative electrode material dust, affecting the normal operation of the used lithium battery recycling equipment. Utility Model Content

[0004] In order to solve the technical problems existing in the background technology, the utility model proposes an exhaust gas treatment device for recycling waste lithium batteries.

[0005] The exhaust gas treatment device for recycling used lithium batteries includes: a low-temperature volatilization furnace connected to an inert gas source, and a low-temperature volatilization furnace exhaust gas outlet, a gas dust removal mechanism, a condenser, a high-temperature incinerator, a centrifugal fan air inlet, and a centrifugal fan air outlet connected to an exhaust pipe.

[0006] Preferably, the gas dust removal mechanism specifically includes a gravity dust collection settling box and a bag dust collector. The air inlet of the gravity dust collection settling box is connected to the exhaust gas outlet of the low-temperature volatilization furnace through the first exhaust gas pipe, the air outlet of the gravity dust collection settling box is connected to the air inlet of the bag dust collector through the second exhaust gas pipe, and the air outlet of the bag dust collector is connected to the air inlet of the condenser through the third exhaust gas pipe.

[0007] Preferably, the gravity dust collection and settling box is provided with a plurality of baffles arranged in an upper and lower staggered manner in the box body between the air inlet and the air outlet of the gravity dust collection and settling box.

[0008] Preferably, the bag dust collector is a pulse bag dust collector.

[0009] Preferably, the outer walls of the first exhaust pipe, the second exhaust pipe and the third exhaust pipe are all provided with a heating structure and are respectively connected to a first temperature sensor, a second temperature sensor and a third temperature sensor which are in communication with the inner cavities of the pipes.

[0010] Preferably, the heating structure is a heating cable evenly wound around the outer walls of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe.

[0011] Preferably, the tail gas outlet of the low-temperature volatilization furnace is connected to a fourth temperature sensor in communication with the furnace cavity.

[0012] Preferably, the gravity dust collection sedimentation box is provided with several first dust collecting hoppers with larger upper part and smaller lower part below the air inlet and the air outlet of the gravity dust collection sedimentation box, and the bottom opening of the first dust collecting hopper is sealedly connected to the first star-shaped discharge valve.

[0013] Preferably, a plurality of second dust collecting hoppers with larger upper portions and smaller lower portions are provided at the bottom end of the pulse bag dust collector, and the bottom openings of the second dust collecting hoppers are sealedly connected to the second star-shaped discharge valves.

[0014] The tail gas treatment device for recycling waste lithium batteries proposed in this utility model has the following beneficial effects:

[0015] By setting up a dust removal mechanism between the tail gas outlet of the low-temperature volatilization furnace and the condenser, impurities such as positive and negative electrode dust in the electrolyte tail gas can be removed, effectively preventing the tail gas pipeline from being blocked by these dust and impurities, and also effectively preventing the subsequent condenser from being contaminated by dust and impurities, thereby improving the purity of the recovered electrolyte and ensuring the working reliability of the low-temperature volatilization furnace.

[0016] First, use a gravity settling box to remove large particles of dust, and then use a bag dust collector to remove small particles of dust, reducing the burden on the bag dust collector. The purified electrolyte tail gas enters the condenser for liquefaction and recovery. Through the reasonable arrangement of the gas dust removal mechanism, not only the purification degree of the electrolyte tail gas is guaranteed, but also the working reliability of the dust removal mechanism itself is guaranteed.

[0017] The heating cables evenly wound around the outer walls of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe can reliably and accurately maintain the temperature of the first exhaust pipe, the second exhaust pipe, and the third exhaust pipe through resistance heating, ensuring that the electrolyte exhaust therein is in a gaseous state, which facilitates subsequent dust removal and recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of an exhaust gas treatment device for recycling waste lithium batteries proposed in the utility model.

[0019] Figure 2 This is a structural schematic diagram of the exhaust gas treatment device for recycling waste lithium batteries proposed by the utility model, from the exhaust gas outlet of the low-temperature volatilization furnace to the exhaust pipe.

[0020] Figure 3 This is a structural schematic diagram of the part from the tail gas outlet of the low-temperature volatilization furnace to the third tail gas pipeline of an exhaust gas treatment device for recycling waste lithium batteries proposed by the utility model. DETAILED DESCRIPTION

[0021] The specific implementation of the tail gas treatment device for recycling waste lithium batteries proposed in the present invention will be described in detail below with reference to the accompanying drawings.

[0022] Reference Figure 1 The exhaust gas treatment device for recycling waste lithium batteries includes: a low-temperature volatilization furnace 2 connected to an inert gas source 1, and a low-temperature volatilization furnace exhaust gas outlet, a gas dust removal mechanism 4, a condenser 5, a high-temperature incinerator 6, a centrifugal fan air inlet, and a centrifugal fan outlet connected to an exhaust pipe 8.

[0023] The inert gas source 1 enters the low-temperature volatilization furnace 2 through the air inlet pipe connected to the tail of the low-temperature volatilization furnace 2 to protect the waste lithium battery fragments in the low-temperature volatilization furnace 2 from oxidation. The inert gas can be nitrogen, helium, etc. In practical applications, the inert gas needs to be a high-purity gas that maintains the oxygen content in the low-temperature volatilization furnace 2 to be less than 1%. When the low-temperature volatilization furnace 2 heats the liquid electrolyte to make it gaseous, the high-purity inert gas in the low-temperature volatilization furnace 2 will carry the volatilized electrolyte gas and the raised positive and negative electrode dust to form an airflow, which will be centrifuged. Under the action of the negative pressure formed by the machine 7, the exhaust gas is sucked into the exhaust pipe 3 from the exhaust outlet of the low-temperature volatilization furnace, and then enters the gas dust removal mechanism 4. The dust removal mechanism 4 can remove the positive and negative electrode dust in the air flow. The high-purity electrolyte volatile gas coming out of the dust removal mechanism 4 continues to be sucked into the condenser 5. The temperature of the condenser is controlled at -20-0°C. In the condenser 5, the electrolyte volatile gas is cooled to a recyclable liquid electrolyte. The remaining gas coming out of the condenser 5 enters the high-temperature incinerator 6, is burned and purified, and is discharged into the atmosphere from the exhaust pipe 8.

[0024] By providing a dust removal mechanism 4 between the exhaust gas outlet of the low-temperature volatilization furnace and the condenser 5, impurities such as positive and negative electrode dust in the electrolyte exhaust gas can be removed, effectively preventing the exhaust gas pipeline from being blocked by these dust and impurities, and also effectively preventing the subsequent condenser 5 from being contaminated by dust and impurities, thereby improving the purity of the recovered electrolyte and ensuring the operating reliability of the low-temperature volatilization furnace 2.

[0025] Reference Figures 1 to 3 The gas dust removal mechanism 4 specifically includes a gravity dust collection settling box 9 and a bag dust collector 10. The air inlet 91 of the gravity dust collection settling box is connected to the exhaust gas outlet of the low-temperature volatilization furnace through the first exhaust gas pipe 31, and the air outlet 92 of the gravity dust collection settling box is connected to the air inlet 101 of the bag dust collector 10 through the second exhaust gas pipe 32. The air outlet 102 of the bag dust collector 10 is connected to the air inlet 51 of the condenser 5 through the third exhaust gas pipe 33.

[0026] First, use the gravity settling box 9 to remove large particles of dust, and then use the bag dust collector 10 to remove small particles of dust, thereby reducing the burden on the bag dust collector 10. The purified electrolyte tail gas enters the condenser 5 for liquefaction and recovery. By reasonably arranging the gas dust removal mechanism 4, not only the purification degree of the electrolyte tail gas can be guaranteed, but also the working reliability of the dust removal mechanism 4 itself can be guaranteed.

[0027] Reference Figure 2 、 Figure 3 The gravity dust collection settling box 9 is provided with a plurality of baffles 93 arranged in an upper and lower staggered manner in the box body between the gravity dust collection settling box air inlet 91 and the gravity dust collection settling box air outlet 92.

[0028] In actual application, the cross-sectional area of ​​the gravity sedimentation box 9 is larger than the cross-sectional area of ​​the first exhaust pipe. The electrolyte exhaust gas volatilized from the exhaust outlet of the low-temperature volatilization furnace will have a lower flow rate after entering the gravity dust removal sedimentation box 9. The positive and negative electrode dust in the electrolyte exhaust gas will sink under the action of their own gravity after colliding with the baffle 93 and separate from the electrolyte gas. Multiple baffles 93 arranged in an upper and lower staggered manner can increase the collision probability of the positive and negative electrode dust, thereby allowing more dust to fall and separate from the electrolyte gas, thereby improving the dust removal effect.

[0029] Reference Figure 2 The bag dust collector 10 is a pulse bag dust collector. When too much positive and negative electrode dust accumulates on the filter bag and the filtration resistance of the filter bag becomes larger, compressed air is ejected from the pulse valve and sprayed to the filter bag through the blowpipe. The filter bag expands and vibrates to shake off the accumulated dust, thereby achieving the effect of automatic cleaning and ensuring the working reliability of the bag dust collector 10.

[0030] Reference Figure 2 、 Figure 3 The outer walls of the first exhaust pipe 31, the second exhaust pipe 32 and the third exhaust pipe 33 are all provided with a heating structure 11 and are respectively connected to a first temperature sensor 12, a second temperature sensor 13 and a third temperature sensor 14 that are connected to the inner cavity of the pipe.

[0031] Since the temperature of electrolyte vaporization is above 150°C, a heating structure 11 and a first temperature sensor 12, a second temperature sensor 13, and a third temperature sensor 14 can be set to ensure and monitor the electrolyte tail gas temperature in the first tail gas pipeline 31, the second tail gas pipeline 32, and the third tail gas pipeline 33 to be above 150°C. In practical applications, the temperature range can be 150°C-200°C, and the heating structure 11 can use steam heating or electric heating.

[0032] Reference Figure 2 、 Figure 3 The heating structure 11 is a heating cable evenly wound around the outer walls of the first exhaust pipe 31, the second exhaust pipe 32, and the third exhaust pipe 33. The heating cable is a heating structure 11 with a relatively simple structure and occupies a small area. It can also maintain the temperature of the first exhaust pipe 31, the second exhaust pipe 32, and the third exhaust pipe 33 more reliably and accurately through resistive heating.

[0033] Reference Figure 1 The exhaust gas outlet of the low-temperature volatilization furnace is connected to a fourth temperature sensor 15 in communication with the furnace chamber. In actual application, in order to make the electrolyte volatilize better from the low-temperature volatilization furnace 2 and prevent the electrolyte from cooling and liquefying in the subsequent exhaust gas pipeline 3 and dust removal mechanism 4, it is generally necessary to ensure that the exhaust gas outlet temperature of the low-temperature volatilization furnace is 250-300°C. The fourth temperature sensor 15 can better monitor whether the exhaust gas outlet temperature of the low-temperature volatilization furnace meets the requirement. If the temperature is too low, the heating temperature of the low-temperature volatilization furnace 2 needs to be increased.

[0034] Reference Figure 2 、 Figure 3 The gravity dust collection sedimentation box 9 is located below the gravity dust collection sedimentation box air inlet 91 and the gravity dust collection sedimentation box air outlet 92, and is provided with several first dust collecting hoppers 94 with larger upper parts and smaller lower parts. The bottom end opening of the first dust collecting hopper 94 is sealed and connected to the first star-shaped unloading valve 95. The first dust collecting hopper 94 can collect larger particles of positive and negative electrode dust that fall from the electrolyte tail gas, and discharge them through the first star-shaped unloading valve 95 to a collection device such as a ton bag for recycling. Since the first star-shaped unloading valve 95 has gas sealing properties, the dust removal of the gravity dust collection sedimentation box 9 will not be affected during the unloading process, thereby improving the continuity of the dust removal work.

[0035] Reference Figure 2 、 Figure 3The bottom end of the pulse bag dust collector is provided with several second dust collecting hoppers 103 which are larger at the top and smaller at the bottom. The bottom opening of the second dust collecting hopper 103 is sealed and connected with a second star-shaped discharge valve 104. The second dust collecting hopper 103 can collect smaller particles of positive and negative electrode dust that fall off in the electrolyte tail gas, and discharge them through the second star-shaped discharge valve 104 to a ton bag or other collection device for recycling. Since the second star-shaped discharge valve 104 has gas sealing properties, the dust removal of the pulse bag dust collector will not be affected during the unloading process, thereby further improving the continuity of the dust removal work.

[0036] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A tail gas treatment device for recycling waste lithium batteries, characterized in that: The invention comprises: a low-temperature volatilization furnace (2) connected to an inert gas source (1), and a low-temperature volatilization furnace tail gas outlet, a gas dust removal mechanism (4), a condenser (5), a high-temperature incinerator (6), and a centrifugal fan air inlet, the centrifugal fan air outlet being connected to an exhaust pipe (8); The gas dust removal mechanism specifically comprises a gravity dust collection settling box (9) and a bag dust collector (10); an air inlet (91) of the gravity dust collection settling box is connected to the tail gas outlet of the low-temperature volatilization furnace through a first tail gas pipe (31); an air outlet (92) of the gravity dust collection settling box is connected to an air inlet (101) of the bag dust collector (10) through a second tail gas pipe (32); and an air outlet (102) of the bag dust collector (10) is connected to an air inlet (51) of the condenser (5) through a third tail gas pipe (33).

2. The tail gas treatment device for recycling waste lithium batteries according to claim 1, characterized in that: The gravity dust collection and settling box (9) is provided with a plurality of baffles (93) arranged in an upper and lower staggered manner in a box body between an air inlet (91) and an air outlet (92) of the gravity dust collection and settling box.

3. The tail gas treatment device for recycling waste lithium batteries according to claim 1, characterized in that: The bag dust collector (10) is a pulse bag type dust collector.

4. The tail gas treatment device for recycling waste lithium batteries according to claim 1, characterized in that: The outer walls of the first tail gas pipeline (31), the second tail gas pipeline (32), and the third tail gas pipeline (33) are all provided with a heat tracing structure (11) and are respectively connected to a first temperature sensor (12), a second temperature sensor (13), and a third temperature sensor (14) that are in communication with the inner cavities of the pipelines.

5. The tail gas treatment device for recycling waste lithium batteries according to claim 4, characterized in that: The heating structure (11) is a heating cable evenly wound around the outer walls of the first tail gas pipeline (31), the second tail gas pipeline (32), and the third tail gas pipeline (33).

6. The tail gas treatment device for recycling waste lithium batteries according to claim 1, characterized in that: The tail gas outlet of the low-temperature volatilization furnace is connected to a fourth temperature sensor (15) which is in communication with the furnace chamber.

7. The tail gas treatment device for recycling waste lithium batteries according to claim 1, characterized in that: The gravity dust collection sedimentation box (9) is provided with a plurality of first dust collecting hoppers (94) with larger upper portions and smaller lower portions below the gravity dust collection sedimentation box air inlet (91) and the gravity dust collection sedimentation box air outlet (92). The bottom openings of the first dust collecting hoppers (94) are sealedly connected to first star-shaped discharge valves (95).

8. The tail gas treatment device for recycling waste lithium batteries according to claim 3, characterized in that: The bottom end of the pulse bag dust collector is provided with a plurality of second dust collecting hoppers (103) that are larger at the top and smaller at the bottom. The bottom openings of the second dust collecting hoppers (103) are sealed and connected to a second star-shaped discharge valve (104).

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