Lithium iron phosphate sintering tail gas treatment and waste heat recycling device

Abstract

The utility model provides a lithium iron phosphate sintering tail gas treatment and waste heat recycling device, which relates to the technical field of lithium iron phosphate production devices, and comprises an incinerator, a waste heat boiler, a heating medium shunting pipeline, a cyclone dust collector, a bag-type dust collector, an adsorption tower and a nitrogen buffer storage tank, the heating medium shunting pipeline comprises a first shunting pipeline connected to a heating medium outlet of the waste heat boiler, a cyclone dust collector connected to a tail gas outlet of the waste heat boiler, a bag-type dust collector connected to a tail gas outlet of the cyclone dust collector, an adsorption tower connected to a tail gas outlet of the bag-type dust collector, and a nitrogen buffer storage tank connected to a gas outlet end of the adsorption tower through a pipeline; the problems that in a traditional treatment scheme, a bag-type dust collector is large in temperature fluctuation and prone to condensation and blockage, and nitrogen is not recycled can be solved.

Description

Technical Field

[0001] This utility model relates to the technical field of lithium iron phosphate production equipment, specifically to a device for treating the combustion end gas and recovering waste heat from lithium iron phosphate combustion. Background Technology

[0002] Lithium iron phosphate (LFP) is a lithium-ion battery electrode material with the chemical formula LiFePO4. It is mainly used in various lithium-ion batteries. The main production processes include mixing, spray drying, sintering, crushing, mixing, baking, and packaging. The production process involves a high-temperature sintering process, which is usually carried out at a high temperature of 700-800℃. During the synthesis of LFP materials at high temperatures, a large amount of high-temperature exhaust gas is generated. This exhaust gas contains heat, carbon monoxide (CO), volatile organic compounds (VOCs), nitrogen (N2), carbon dioxide (CO2), and fine particulate dust.

[0003] Currently, the industry mainly uses multi-stage treatment plus heat recovery to treat the exhaust gas from lithium iron phosphate combustion. This involves recovering the heat energy from the exhaust gas for heating in the production process, followed by baghouse dust collection, VOC adsorption, and high-cylinder emission. This approach effectively achieves energy reuse, but traditional methods still have the following problems: firstly, the baghouse dust collector experiences large temperature fluctuations, making it prone to condensation and blockage; secondly, nitrogen in the exhaust gas is not recovered. Therefore, this application proposes a device for treating the exhaust gas from lithium iron phosphate combustion and recovering waste heat. Utility Model Content

[0004] In order to overcome the problems in the background technology, this utility model provides a device for treating the combustion end gas of lithium iron phosphate and recovering waste heat, which solves the problems of large temperature fluctuations, easy condensation and blockage, and lack of nitrogen recovery in traditional treatment schemes.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0006] A device for treating exhaust gas and recovering waste heat from lithium iron phosphate combustion includes an incinerator, a waste heat boiler, a heat medium diversion pipeline, a cyclone dust collector, a bag filter dust collector, an adsorption tower, and a nitrogen buffer tank. The inlet of the incinerator is connected to the sintering process outlet via a tail gas inlet pipeline. The waste heat boiler has a heat medium heat exchange tube bundle inside, and its inlet is connected to the outlet of the incinerator via a pipeline. The heat medium diversion pipeline includes a first diversion pipeline, the inlet of which is connected to the heat medium outlet of the waste heat boiler, and the outlet of which is connected to a secondary heat exchanger. The inlet of the cyclone dust collector is connected to the exhaust gas outlet of the waste heat boiler via a pipeline. The inlet of the bag filter dust collector is connected to the exhaust gas outlet of the cyclone dust collector via a pipeline. The inlet of the adsorption tower is connected to the exhaust gas outlet of the bag filter dust collector via a pipeline. The nitrogen buffer tank is connected to the outlet of the adsorption tower via a pipeline.

[0007] Furthermore, the bag filter is equipped with an insulation sleeve.

[0008] Furthermore, the heat medium diversion pipeline includes a second diversion pipeline, the inlet of which is connected to the heat medium outlet of the waste heat boiler, and the outlet of which is connected to the heat medium inlet of the insulation jacket.

[0009] Furthermore, a cooler is connected between the cyclone dust collector and the waste heat boiler.

[0010] The beneficial effects of this utility model are:

[0011] This application utilizes a waste heat boiler to recover waste heat from the exhaust gas and applies it to upstream spray drying and the bag filter dust collection system of this process. This ensures that the bag filter dust collector operates under stable temperature conditions, effectively preventing filter bag condensation and clogging, improving the dust removal efficiency and long-term stability of the system. At the same time, through multi-stage filtration, nitrogen is recovered and reused, avoiding resource waste and improving the system's energy utilization rate and operational economy. This solves the problems of large temperature fluctuations, easy condensation and clogging, and lack of nitrogen recovery in traditional treatment schemes for bag filter dust collectors. Attached Figure Description

[0012] To clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments are explained.

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0014] Figure 2 This is a schematic diagram of the waste heat boiler structure of this utility model.

[0015] 1-Incinerator, 11-Tail gas inlet pipe, 2-Waste heat boiler, 21-Heat medium heat exchange tube bundle, 3-Heat medium diversion pipe, 31-First diversion pipe, 32-Second diversion pipe, 4-Cyclone dust collector, 5-Bag filter dust collector, 6-Adsorption tower, 7-Nitrogen buffer storage tank, 8-Secondary heat exchanger, 9-Cooler. Detailed Implementation

[0016] To make the objectives, technical solutions, and beneficial effects of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, so as to facilitate the understanding of those skilled in the art.

[0017] This utility model discloses a device for treating the combustion exhaust gas and recovering waste heat from lithium iron phosphate combustion. (See reference...) Figure 1-2 A device for treating exhaust gas and recovering waste heat from the sintering of lithium iron phosphate includes an incinerator 1, a waste heat boiler 2, a heat medium distribution pipeline 3, a cyclone dust collector 4, a bag filter 5, an adsorption tower 6, and a nitrogen buffer storage tank 7. The incinerator 1 is connected to the sintering process outlet via an exhaust gas inlet pipeline 11, introducing the 700-800°C high-temperature exhaust gas generated during the lithium iron phosphate sintering process into the system through a ceramic-lined stainless steel pipe. The incinerator 1 is a direct-fired incinerator 50, which is equipped with a combustion chamber and a combustion chamber. The waste heat boiler 2 includes a burner, an auxiliary air supply pipeline, and an online monitoring device. The burner heats the exhaust gas to 850–1100°C, oxidizing and decomposing the CO and VOCs. The auxiliary air supply pipeline automatically adjusts the air volume to ensure complete combustion. The inlet 22 of the waste heat boiler 2 is connected to the outlet 1 via a pipeline to recover the heat energy from the high-temperature exhaust gas after combustion in the incinerator 1. The waste heat boiler 2 contains a heat exchanger tube bundle 21 to convert the exhaust gas heat energy into steam or hot water. The heat medium diversion pipeline 3 includes a first diversion pipeline 31. The inlet of the first diversion pipeline 31 is connected to the heat medium outlet of the waste heat boiler 2, and the outlet of the first diversion pipeline 31 is connected to the secondary heat exchanger 8. This is used to transfer heat from the heat medium to the inlet air preheating system, forming spray-dried preheated air. The inlet of the cyclone dust collector 4 is connected to the exhaust gas outlet of the waste heat boiler 2 via a pipeline, using centrifugal separation to remove moisture and large dust particles from the exhaust gas. The inlet of the bag filter 5 is connected via a pipeline... The exhaust outlet of the cyclone dust collector 4 removes small particulate dust from the exhaust gas. The inlet of the adsorption tower 6 is connected to the exhaust outlet of the bag filter 5 through a pipeline to remove residual VOCs and organic gaseous pollutants from the exhaust gas. The adsorption tower is equipped with an activated carbon filling layer and an online VOC monitoring device to monitor the VOC concentration before and after the adsorption tower. The nitrogen buffer storage tank 7 is connected to the outlet of the adsorption tower 6 through a pipeline to store and enrich nitrogen, and is connected to an external nitrogen purification system through a pipeline.

[0018] See Figure 1-2The bag filter 5 is equipped with an insulation sleeve 51 to ensure its internal temperature and prevent condensation on the filter bags.

[0019] See Figure 1-2 The heat medium diversion pipeline 3 includes a second diversion pipeline 32. The inlet of the second diversion pipeline 32 is connected to the heat medium outlet of the waste heat boiler 2, and the outlet of the second diversion pipeline 32 is connected to the heat medium inlet of the insulation sleeve 51 to ensure that the outer shell temperature of the bag dust collector 5 is higher than the dew point and to avoid condensation and blockage of the filter bags. The outlet of the insulation sleeve 51 of the bag dust collector 5 is connected to the water inlet of the waste heat boiler 2.

[0020] See Figure 1-2 A cooler 9 is connected between the cyclone dust collector 4 and the waste heat boiler 2. The exhaust gas temperature is reduced to 30-60℃ by heat exchange to ensure the stable operation of the subsequent processing unit.

[0021] Work process:

[0022] The high-temperature exhaust gas (700-800℃) generated during the lithium iron phosphate sintering process is first directly introduced into a direct-fired incinerator 1 via an exhaust gas inlet pipeline for high-temperature combustion and purification. During this stage, incinerator 1 automatically adjusts the air volume through an auxiliary air supply pipeline, ensuring that CO and VOCs in the exhaust gas are fully combusted and decomposed under high-temperature conditions. This ensures that pollutants such as hydrocarbons, volatile organic compounds (VOCs), and CO are completely oxidized, while reducing the generation of secondary pollutants. An online detection device monitors CO, CO2, and combustion temperature in real time, and the exhaust gas remains at a high temperature even after high-temperature combustion. The exhaust gas then enters the waste heat boiler 2 for heat recovery. In the waste heat boiler 2, the exhaust gas passes through the high-temperature shell-and-tube waste heat boiler, where the heat exchange tube bundle inside absorbs the heat energy of the exhaust gas and converts it into steam or hot water for process use or spray drying preheating. At the same time, it further reduces the temperature of the exhaust gas. After the waste heat is recovered, the temperature of the exhaust gas drops and then enters the heat medium diversion pipeline 3. The first diversion pipeline 31 delivers part of the heat medium to the secondary heat exchanger 8 for inlet preheating, while the second diversion pipeline 32 provides heat to the insulation sleeve 51 of the bag filter 5 through a special insulation pipe to prevent condensation and blockage of the filter bag.

[0023] The exhaust gas, after incineration purification and waste heat recovery, first passes through cooler 9 to further reduce its temperature, ensuring stable operation of subsequent processing units. It then enters cyclone dust collector 4 to remove large particles of dust and moisture, reducing the moisture content and dust concentration of the exhaust gas. The cooled exhaust gas then enters bag filter 5 for fine dust removal, and is periodically cleaned by an automatic pulse backflushing system to keep the filter bags unobstructed and improve dust removal efficiency. Afterward, the exhaust gas enters an adsorption tower to adsorb VOC organic pollutants. The exhaust gas, after multi-stage purification, then enters nitrogen buffer storage tank 7 for storage and recycling.

[0024] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A device for treating the exhaust gas and recovering waste heat from the combustion of lithium iron phosphate, characterized in that: The system includes an incinerator (1), a waste heat boiler (2), a heat medium distribution pipeline (3), a cyclone dust collector (4), a bag filter (5), an adsorption tower (6), and a nitrogen buffer storage tank (7). The inlet of the incinerator (1) is connected to the sintering process outlet via a tail gas inlet pipeline (11). The waste heat boiler (2) is equipped with a heat medium heat exchange tube bundle (21). The inlet of the waste heat boiler (2) is connected to the outlet of the incinerator (1) via a pipeline. The heat medium distribution pipeline (3) includes a first distribution pipeline (31). The inlet of the pipeline (31) is connected to the heat medium outlet of the waste heat boiler (2), the outlet of the first diversion pipeline (31) is connected to the secondary heat exchanger (8), the inlet of the cyclone dust collector (4) is connected to the tail gas outlet of the waste heat boiler (2) through a pipeline, the inlet of the bag filter (5) is connected to the tail gas outlet of the cyclone dust collector (4) through a pipeline, the inlet of the adsorption tower (6) is connected to the tail gas outlet of the bag filter (5) through a pipeline, and the nitrogen buffer storage tank (7) is connected to the outlet of the adsorption tower (6) through a pipeline.

2. The lithium iron phosphate combustion tail gas treatment and waste heat recovery device according to claim 1, characterized in that: The bag filter (5) is equipped with an insulation sleeve (51).

3. The lithium iron phosphate combustion tail gas treatment and waste heat recovery device according to claim 2, characterized in that: The heat medium diversion pipeline (3) includes a second diversion pipeline (32), the inlet of which is connected to the heat medium outlet of the waste heat boiler (2), and the outlet of which is connected to the heat medium inlet of the insulation jacket (51).

4. The lithium iron phosphate combustion tail gas treatment and waste heat recovery device according to claim 2, characterized in that: A cooler (9) is connected between the cyclone dust collector (4) and the waste heat boiler (2).

Images