System for recovering oxygen from tail gas of smelting furnace of ternary lithium anode material and utilizing waste heat

Abstract

The utility model relates to gas recovery technical field discloses a kind of oxygen recovery and waste heat utilization system of ternary lithium anode material smelting kiln tail gas, including heat exchanger, dust collector, gas-water separator, filter and gas holder, heat exchanger includes primary heat exchanger, secondary heat exchanger and tertiary heat exchanger, primary heat exchanger and furnace kiln are connected, dust collector is equipped between primary heat exchanger and secondary heat exchanger, and secondary heat exchanger is connected with gas-water separator a, fan, tertiary heat exchanger, filter a, gas-water separator a, gas holder a, compressor, gas holder b, adsorption system, filter b and gas holder c. The sensible heat of kiln flue gas can be recycled, hot water or steam is generated, or normal temperature oxygen entering kiln is heated, the acquisition rate of oxygen is improved, oxygen is recycled, energy is saved, cost is reduced, enterprise benefit is improved, and environment is protected simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of gas recovery technology, specifically to a system for oxygen recovery and waste heat utilization from tail gas of ternary lithium anode material smelting kilns. Background Technology

[0002] In recent years, with increasingly fierce competition in the lithium battery industry, the growing environmental and climate issues have attracted widespread attention, making it imperative to build low-carbon, clean, and efficient enterprises.

[0003] During the high-temperature smelting of ternary lithium anode materials in a furnace, a high-purity oxygen environment of over 99% is required to ensure reaction efficiency and improve purity. This necessitates the continuous introduction of 99% oxygen and the discharge of oxygen tail gas containing some impurities. The temperature of the oxygen tail gas discharged from different locations in the furnace ranges from 400℃ to 750℃, with an oxygen content of approximately 98%. The remaining components are water and carbon dioxide generated during furnace production, as well as lithium oxide dust carried by the airflow. The oxygen tail gas discharged from the furnace is over 98% oxygen, representing significant value; its high temperature and high sensible heat allow for recovery; and the presence of some lithium oxide dust in the tail gas also allows for recycling.

[0004] Existing oxygen exhaust gas treatment processes and their disadvantages:

[0005] Current process: The oxygen exhaust gas discharged from the kiln is mixed with the ambient air in the kiln outlet pipe and cooled down before being directly discharged into the atmosphere through the fan.

[0006] The disadvantages are:

[0007] The exhaust gas from kilns is 98% oxygen. Directly releasing it wastes oxygen and increases the company's costs.

[0008] The volatile organic compounds contained in the kiln exhaust gas at temperatures between 400℃ and 750℃ were not recovered, resulting in a waste of energy.

[0009] The kiln exhaust gas was discharged directly into the air without dust removal, resulting in the loss of lithium oxide in the exhaust gas and the failure of the exhaust gas dust emissions to meet environmental protection standards.

[0010] CN 217972615 U discloses an energy-saving polycrystalline silicon production tail gas recovery system. The tail gas outlet of the reduction furnace is connected to the shell-side inlet of a first heat exchanger; the gas phase outlet of the first heat exchanger is connected to the shell-side inlet of a second heat exchanger; the gas phase outlet of the second heat exchanger is connected to the waste gas inlet of an absorption tower; the cold hydrogen outlet of the absorption tower is connected to the tube-side inlet of the second heat exchanger; the rich liquid outlet of the absorption tower is connected to the tube-side inlet of the first heat exchanger; the liquid phase outlets of both the first and second heat exchangers are connected to the shell-side inlet of a third heat exchanger; the shell-side outlet of the third heat exchanger is connected to the rich liquid inlet of a stripping tower; the lean liquid outlet of the stripping tower is connected to the tube-side inlet of the third heat exchanger; and the tube-side outlet of the third heat exchanger is connected to the lean liquid inlet of the absorption tower. Before the gas enters the hydrogen storage tank, it undergoes adsorption but not filtration, making it prone to carrying particles or impurities into the storage tank, affecting purification. Utility Model Content

[0011] To address the aforementioned issues, this utility model discloses an oxygen recovery and waste heat utilization system for the tail gas of a ternary lithium anode material smelting kiln. This system improves the oxygen acquisition rate, enabling the reuse of oxygen, saving energy, reducing costs, and increasing enterprise efficiency, while also protecting the environment.

[0012] The technical solution of this utility model is: an oxygen recovery and waste heat utilization system for tail gas of ternary lithium anode material smelting kiln, including a heat exchanger, a dust collector, a gas-liquid separator, a filter, and a gas storage tank. The heat exchanger includes a primary heat exchanger, a secondary heat exchanger, and a tertiary heat exchanger. The primary heat exchanger is connected to the kiln. A dust collector is provided between the primary heat exchanger and the secondary heat exchanger. The secondary heat exchanger is connected to a gas-liquid separator a, a fan, a tertiary heat exchanger, a filter a, a gas-liquid separator a, a gas storage tank a, a compressor, a gas storage tank b, an adsorption system, a filter b, and a gas storage tank c.

[0013] By adopting the above technical solution, the cooled, purified flue gas with liquid water removed is pressurized, and then the moisture and carbon dioxide contained in the flue gas are removed by pressure swing adsorption, thereby improving the purity of oxygen to meet the requirements of kiln use. After depressurization, the oxygen is directly returned to the kiln for use, realizing the recovery and recycling of oxygen.

[0014] Preferably, a venting system is provided between the furnace and the primary heat exchanger, and two dust collectors are provided between the primary and secondary heat exchangers in parallel. Hot water is discharged from the primary and secondary heat exchangers through pipelines.

[0015] By adopting the above technical solution and setting the heat exchangers in parallel, the other heat exchanger can still work normally even if one heat exchanger fails, preventing the entire system from collapsing.

[0016] Preferably, the dust collector is a ceramic fiber cartridge dust collector, the outer shell of the dust collector is made of stainless steel, and the dust collector is cleaned with nitrogen.

[0017] By adopting the above technical solution, when the kiln flue gas passes through the dust collector, the dust is blocked on the ceramic filter cartridge. After running for a period of time, the change in resistance before and after the dust collector activates the nitrogen pulse to remove the dust adhering to the ceramic filter cartridge and let it fall into the bottom ash hopper.

[0018] Preferably, air tank a and air tank b are connected to the air inlet pipe and air outlet pipe of the compressor, respectively, and the compressors are connected in parallel. A venting system is provided between air tank a and the compressor.

[0019] By adopting the above technical solutions, the compressor opening mode can buffer the flow and avoid the instantaneous suction force from affecting the pressure stability of the flue gas in the kiln. The exhaust pipe can prevent high-pressure flue gas from directly impacting the subsequent pressure swing adsorption equipment.

[0020] Preferably, the compressor is a reciprocating compressor.

[0021] By adopting the above technical solution, the pressure requirements of pressure swing adsorption are met.

[0022] Preferably, the adsorption system is equipped with a venting system.

[0023] By adopting the above technical solution

[0024] Preferably, the heat exchangers are equipped with temperature sensors.

[0025] By adopting the above technical solution, the temperature change of the heat exchanger can be monitored in real time.

[0026] The advantages of this utility model are: 1. This utility model places the dust collector between the primary heat exchanger and the secondary heat exchanger, which avoids the condensation of moisture in the kiln exhaust gas after cooling, which would combine with the lithium oxide in the exhaust gas to form a highly corrosive lithium hydroxide solution, causing corrosion to the pipes and equipment.

[0027] 2. The pressure swing adsorption system of this utility model is equipped with a filter to prevent the adsorbent such as molecular grids in pressure swing adsorption from entering the subsequent pipeline after being washed by the airflow, which would affect the purity of oxygen and the recovery effect.

[0028] 3. This utility model can recover and utilize the sensible heat of kiln flue gas to generate hot water or steam, or to heat ambient oxygen entering the kiln, thereby improving the oxygen acquisition rate, enabling the reuse of oxygen, saving energy, reducing costs, improving enterprise efficiency, and also playing a role in protecting the environment. Attached Figure Description

[0029] Figure 1This is a schematic diagram showing the exhaust gas in the furnace of this utility model passing through a primary heat exchanger, a dust collector, and a secondary heat exchanger.

[0030] Figure 2 For the exhaust gas of this utility model Figure 1 A schematic diagram showing the secondary heat exchanger passing through gas-liquid separator a to gas storage tank a;

[0031] Figure 3 For the exhaust gas of this utility model Figure 2 A schematic diagram showing the flow of gas from storage tank a to storage tank b via a compressor.

[0032] Figure 4 For the exhaust gas of this utility model Figure 3 A schematic diagram showing the process from gas storage tank b through the adsorption system to final depressurization and discharge from gas storage tank c.

[0033] The components are: 1. Furnace, 2. Primary heat exchanger, 3. Dust collector, 4. Secondary heat exchanger, 5. Gas-water separator a, 6. Fan, 7. Tertiary heat exchanger, 8. Filter a, 9. Gas-water separator b, 10. Gas storage tank a, 11. Compressor, 12. Gas storage tank b, 13. Adsorption system, 14. Filter b, 15. Gas storage tank c. Detailed Implementation

[0034] The technical solutions in the embodiments of this utility model will now be clearly and completely described with reference to the accompanying drawings.

[0035] like Figure 1-4 As shown, the oxygen recovery and waste heat utilization system for the tail gas of a ternary lithium anode material smelting kiln includes a heat exchanger, a dust collector 3, a gas-liquid separator, a filter, and a gas storage tank. The heat exchanger includes a primary heat exchanger 2, a secondary heat exchanger 4, and a tertiary heat exchanger 7. The primary heat exchanger 2 is connected to the kiln 1. A dust collector 3 is installed between the primary heat exchanger 2 and the secondary heat exchanger 4. The secondary heat exchanger 4 is connected to a gas-liquid separator a5, a fan 6, a tertiary heat exchanger 7, a filter a8, a gas-liquid separator a5, a gas storage tank a10, a compressor 11, a gas storage tank b12, an adsorption system, a filter b, and a gas storage tank c. After the flue gas is cooled, purified, and has had liquid water removed, it is pressurized and then the water and carbon dioxide contained in the flue gas are removed by pressure swing adsorption, thereby improving the purity of the oxygen to meet the requirements of the kiln 1. After depressurization, the oxygen is directly returned to the kiln 1 for use, realizing the recovery and recycling of oxygen.

[0036] A venting system is provided between the furnace and the primary heat exchanger 2. Two dust collectors 3 are provided between the primary heat exchanger 2 and the secondary heat exchanger 4, and they are connected in parallel. The primary heat exchanger 2 and the secondary heat exchanger 4 discharge hot water through pipes. By setting the heat exchangers in parallel, the other heat exchanger can still work normally if one heat exchanger fails, so that the entire system does not collapse.

[0037] Dust collector 3 is a ceramic fiber filter cartridge dust collector. The outer shell of dust collector 3 is made of stainless steel. Dust collector 3 is cleaned with nitrogen. When the flue gas from kiln 1 passes through dust collector 3, the dust is blocked on the ceramic filter cartridge. After running for a period of time, the change in resistance before and after dust collector 3 activates the nitrogen pulse to remove the dust adhering to the ceramic filter cartridge and let it fall into the bottom ash hopper.

[0038] Gas storage tanks a and b are connected to the inlet pipe and outlet pipe 11 of the compressor, respectively. The compressors 11 are connected in parallel. A venting system is provided between the gas storage tanks a10 and the compressors 11. The compressors 11 can be opened to buffer and avoid the instantaneous suction from affecting the pressure stability of the flue gas in the kiln 1. The outlet pipe can prevent the high-pressure flue gas from directly impacting the pressure swing adsorption equipment behind it.

[0039] Compressor 11 is a reciprocating compressor, which meets the pressure requirements of pressure swing adsorption.

[0040] The adsorption system 13 is equipped with a venting system, and the heat exchangers are equipped with temperature detection devices, which can monitor the temperature changes of the heat exchangers in real time.

[0041] Working Principle: The exhaust gas from the kiln passes through the primary heat exchanger 2, where its temperature is reduced. The hot water within the primary heat exchanger 2 carries away the heat, further lowering the exhaust gas temperature. The exhaust gas then passes through a dust collector 3, positioned between the primary and secondary heat exchangers 2 and 4, to prevent moisture condensation after cooling. This moisture condenses and combines with lithium oxide in the exhaust gas to form a highly corrosive lithium hydroxide solution, which would corrode pipes and equipment. The exhaust gas then passes through a gas-liquid separator a5 to separate the moisture. A fan 6 rapidly blows the exhaust gas towards the tertiary heat exchanger 7, which further cools the exhaust gas. Finally, the exhaust gas enters a filter b14 and a gas-liquid separator b9 for further cooling. Further drying and purification are performed. The exhaust gas is stored in storage tank a10 and then enters storage tank b12 via compressor 11. The compressor's open-type design provides buffering, preventing the instantaneous suction from affecting the pressure stability of the flue gas in the kiln. The gas in storage tank b12 passes through adsorption system 13. The storage tank prevents high-pressure flue gas from directly impacting the subsequent adsorption system 13. After passing through adsorption system 13, the gas passes through filter b14 for further filtration. Filter b14 prevents adsorbents such as molecular grids in pressure swing adsorption from entering subsequent pipelines after being washed by the airflow, which would affect the purity of oxygen and the recovery effect. The gas in filter b14 is stored in storage tank c15 and then returned to kiln 1 for use after depressurization.

[0042] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functions and structural principles of the present invention have been shown and explained in the embodiments. Without departing from the stated principles, the implementation of the present invention may have any variations or modifications.

Claims

1. A system for oxygen recovery and waste heat utilization from tail gas of a ternary lithium anode material smelting kiln, comprising a heat exchanger, a dust collector, a gas-liquid separator, a filter, and a gas storage tank, wherein the heat exchanger comprises a primary heat exchanger, a secondary heat exchanger, and a tertiary heat exchanger, and the primary heat exchanger is connected to the kiln, characterized in that: A dust collector is provided between the primary heat exchanger and the secondary heat exchanger. The secondary heat exchanger is connected to a gas-water separator a, a fan, a tertiary heat exchanger, a filter a, a gas-water separator a, a gas storage tank a, a compressor, a gas storage tank b, an adsorption system, a filter b, and a gas storage tank c.

2. The oxygen recovery and waste heat utilization system for the tail gas of the ternary lithium anode material smelting kiln according to claim 1, characterized in that: A venting system is provided between the furnace and the primary heat exchanger. Two dust collectors are provided between the primary and secondary heat exchangers and are connected in parallel. Hot water is discharged from the primary and secondary heat exchangers through pipelines.

3. The oxygen recovery and waste heat utilization system for the tail gas of the ternary lithium anode material smelting kiln according to claim 1, characterized in that: The dust collector is a ceramic fiber cartridge dust collector, the outer shell of the dust collector is made of stainless steel, and the dust collector is cleaned with nitrogen.

4. The oxygen recovery and waste heat utilization system for the tail gas of the ternary lithium anode material smelting kiln according to claim 1, characterized in that: The gas storage tanks a and b are respectively connected to the air inlet pipe and air outlet pipe of the compressor. The compressors are connected in parallel. A venting system is provided between the gas storage tank a and the compressor.

5. The oxygen recovery and waste heat utilization system for the tail gas of the ternary lithium anode material smelting kiln according to claim 1, characterized in that: The compressor is a reciprocating compressor.

6. The oxygen recovery and waste heat utilization system for the tail gas of the ternary lithium anode material smelting kiln according to claim 1, characterized in that: The adsorption system is equipped with a venting system.

7. The oxygen recovery and waste heat utilization system for the tail gas of the ternary lithium anode material smelting kiln according to claim 1, characterized in that: Temperature sensors are installed on all the heat exchangers.

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