CN-122010220-A - Device and method for comprehensively utilizing waste water and waste heat in production of positive electrode material

CN122010220ACN 122010220 ACN122010220 ACN 122010220ACN-122010220-A

Abstract

The invention relates to a comprehensive utilization device and method of waste water and waste heat in the production of a positive electrode material, wherein the comprehensive utilization device of the waste water and the waste heat in the production of the positive electrode material comprises a main system and an auxiliary system, the main system comprises a sanding machine, a main spray drying tower and a powder recovery device, the auxiliary system comprises a waste water collecting tank, an auxiliary spray drying area, a waste gas mixing cavity, a heat pump unit, a condensed water collecting box and a control unit, and the auxiliary spray drying area is positioned at the top of the inside of the main spray drying tower. The comprehensive utilization device of the waste water and the waste heat in the production of the anode material is provided with the independent special line treatment system of the sand mill waste water and the spray drying waste water, and simultaneously, the deep integration of a heat pump system and a spray drying process is introduced, and a feedback control system based on the real-time monitoring of the state of mixed waste gas is established, so that the comprehensive utilization of the waste water and the preheating generated in the production process of the anode material is realized.

Inventors

WEN YANLIANG
ZHENG XIAOXIA
ZHU ZHENGWEI
ZHAO YUZE
HONG MINGZI
WEI FEI

Assignees

鄂尔多斯实验室

Dates

Publication Date: 20260512
Application Date: 20260313

Claims (10)

1. The device for comprehensively utilizing the waste water and the waste heat in the production of the positive electrode material is characterized by comprising a main system and an auxiliary system; along the flowing direction of the wastewater, the main system comprises a sanding machine, a main spray drying tower and a powder recovery device which are sequentially connected; Along the flowing direction of the wastewater, the auxiliary system comprises a wastewater collection tank, an auxiliary spray drying area, a waste gas mixing cavity, a heat pump unit, a condensed water collection tank and a control unit which are connected in sequence; the secondary spray drying zone is located at the top of the interior of the primary spray drying tower.
2. The apparatus for comprehensive utilization of waste water and waste heat in the production of positive electrode materials according to claim 1, wherein the inlet of the waste water collection tank is connected with the outlet of the sander and the water outlet of the main spray drying tower respectively through pipelines; And/or, an atomizer is arranged in the auxiliary spray drying zone; and/or the feeding pipeline of the atomizer is provided with a flowmeter and a regulating valve; and/or, the air outlet of the auxiliary spray drying area and the air outlet of the main spray drying area are connected with the inlet of the waste gas mixing cavity through a heat insulation pipeline; And/or a guide plate and/or a static mixer are arranged in the waste gas mixing cavity; and/or a temperature sensor and a humidity sensor are arranged on the pipeline at the outlet of the waste gas mixing cavity; And/or, the heat pump unit comprises an evaporator.
3. The device for comprehensively utilizing waste water and waste heat in the production of the positive electrode material according to claim 2, wherein the evaporator has a shell-and-tube structure; And/or the outlet of the waste gas mixing cavity is connected with the inlet of the shell side of the evaporator through an induced draft fan; And/or the outlet of the evaporator shell side is connected with the inlet of the condensed water collecting tank; and/or the condensed water collecting box outlet is connected with the sander inlet through a recycling pipeline; And/or, a water quality monitor is arranged on the recycling pipeline; And/or, the outlet of the evaporator tube pass is connected with the inlet of the scroll compressor; And/or, the outlet of the scroll compressor is connected with a condenser.
4. The device for comprehensively utilizing waste water and waste heat in the production of the positive electrode material according to claim 3, wherein the condenser is of a shell-and-tube structure, a tube side of the condenser passes through a refrigerating working medium, and a shell side passes through a preheating medium; and/or, the preheating medium comprises ambient air; and/or, the outlet of the condenser shell side is connected with the inlet of the preheater; And/or the outlet of the preheater is connected with the inlet of the drying spray tower.
5. The device for comprehensively utilizing the waste water and the waste heat in the production of the positive electrode material according to claim 1, wherein the control unit comprises a data monitoring mechanism and an executing mechanism which are electrically connected, wherein the data monitoring mechanism comprises a temperature sensor, a humidity sensor and a liquid level device; And/or the material outlet of the main spray drying tower and the material outlet of the auxiliary spray drying area are connected with the powder recovery device through an ejector, and the structure of the ejector is a venturi tube structure.
6. The apparatus for comprehensive utilization of waste water and waste heat in the production of positive electrode materials according to claim 1, wherein the waste water collection tank comprises an anchor stirrer and a liquid level meter; and/or the sander and the spray drying tower are respectively connected with the wastewater collection tank through pipelines.
7. The device for comprehensively utilizing waste water and waste heat in the production of the positive electrode material according to claim 4, wherein the evaporation temperature of the refrigerating working medium is 5-10 ℃; and/or the material of the refrigerating working medium is environment-friendly R134a; And/or the heat pump unit is a compression heat pump with a variable frequency driving function.
8. A method for comprehensively utilizing waste water and waste heat in the production of a positive electrode material, which is characterized in that the method is carried out in the waste water and waste heat comprehensive utilization device in the production of the positive electrode material according to any one of claims 1 to 7; The positive electrode material comprises any one of lithium iron phosphate, lithium manganese iron phosphate or polyanion positive electrode material.
9. The method according to claim 8, characterized in that it comprises the steps of: S1, wastewater collection, namely conveying the wastewater of a sander and the wastewater of the positive electrode material in a main spray drying tower to a wastewater collection tank, stirring and homogenizing to obtain mixed wastewater, and sending a signal to a control unit by a liquid level device when a liquid level meter in the wastewater collection tank reaches a set high value, and starting the subsequent steps; s2, spray drying, namely conveying the mixed wastewater obtained in the step S1 to an auxiliary spray drying area at the top of a main spray drying tower, atomizing the mixed wastewater into droplet groups through an atomizer in the auxiliary spray drying area, and drying to obtain recovered powder and water vapor; S3, waste gas mixing, namely, enabling the water vapor obtained in the step S2 and the water vapor generated in the main spray drying tower to enter a waste gas mixing cavity to form mixed waste gas; S4, heat energy extraction and lifting, namely conveying the mixed waste gas obtained in the step S3 to the shell side of the shell-and-tube evaporator through a draught fan, enabling a refrigerating working medium to flow in the tube side, and condensing latent heat released by the mixed waste gas into first evaporating waste water through heat exchange, enabling the refrigerating working medium to absorb the latent heat into a gaseous working medium, enabling the gaseous working medium to enter a scroll compressor, converting the gaseous working medium into high-temperature high-pressure gas, conveying the high-temperature high-pressure gas into the shell side of the shell-and-tube condenser, performing heat exchange with air passing through the tube side, heating the air, introducing the air into a spray drying tower through a main draught fan, condensing the high-temperature high-pressure gas into low-temperature liquid, and returning the low-temperature liquid into the tube side of the evaporator for next circulation heat exchange; S5, recycling heat energy, namely introducing the heated preheating medium obtained in the step S4 into a spray drying tower through a main induced draft fan to realize heat energy recycling; s6, recycling the dry powder, namely conveying the recycled powder obtained in the step S2 into a powder recycling device through an ejector with a venturi tube structure; and S7, recycling the condensed water, namely injecting the first evaporation wastewater obtained in the step S4 into a sander through a corrosion-resistant vertical centrifugal pump to recycle the condensed water.
10. The method according to claim 9, wherein the droplet population of step S2 has a particle size of 60 μm to 120 μm; and/or the dew point of the mixed exhaust gas of the step S4 is 30-50 ℃; And/or, the preheating medium in the step S5 is introduced into the spray drying tower, and the preheating medium further comprises heat provided by an auxiliary heat source; and/or, the powder recovery device in the step S6 also recovers the dried positive electrode material obtained by the main spray drying tower.

Description

Device and method for comprehensively utilizing waste water and waste heat in production of positive electrode material Technical Field The invention relates to the technical field of low-temperature waste heat recycling of industrial waste water and waste gas, in particular to a device and a method for comprehensively utilizing waste water and waste heat in the production of a positive electrode material. Background With the rapid development of new energy automobile industry, lithium iron phosphate is used as a main current anode material, the productivity of the lithium iron phosphate is continuously expanded, and the resource consumption and the environmental impact in the production process are increasingly prominent. In the wet process of producing lithium iron phosphate, sand mill and spray drying are used as key production equipment, and specific waste water is produced during regular cleaning and maintenance, and the waste water contains trace lithium iron phosphate raw material particles and has recovery value. The traditional treatment mode mostly adopts flocculation, precipitation and other processes to treat the wastewater by adopting a mixed wastewater system of a whole plant, and the characteristics of low solid content, relatively simple components and high reusability of the wastewater cannot be fully considered, so that the treatment process is long, the cost is high, and valuable components in the wastewater cannot be directly recovered. Meanwhile, the energy consumption of the spray drying process in the production process is remarkable, and a large amount of condensation latent heat contained in low-temperature high-humidity waste gas discharged by the spray drying process is not effectively utilized, so that energy waste is caused. Under the strategic background of carbon neutralization, the development of a resource and low-energy treatment technology for special wastewater has important significance. At present, the scheme commonly used in the prior art can be summarized into a mode of 'mixed wastewater evaporation concentration+simple waste heat utilization'. According to the scheme, various waste water (including reaction mother liquor, washing waste water and sand mill waste water) in the lithium iron phosphate production is mixed and collected, and then concentrated through a multi-effect evaporator. In the aspect of waste heat utilization, the scheme carries out preliminary preheating on mixed waste water through a conventional heat exchanger by using waste heat at a medium temperature of 100-400 ℃ generated in the working procedures of sintering, drying and the like, and then enters an evaporation system. The concentrate is finally cooled to crystallize to recover part of the solid product. However, the proposal has several obvious defects that firstly, the waste water of the sand mill and the waste water of other processes are mixed and treated, the waste water with different properties mutually interfere, especially, the trace lithium iron phosphate raw material in the waste water of the sand mill is difficult to directly recycle due to dilution and pollution, and finally, only low-value mixed salt can be formed, and the recycling degree is limited. Secondly, the scheme is rough in utilization of waste heat, and an effective grade improving means is lacked for a large amount of low-temperature waste heat, so that the waste heat cannot meet the heat requirement of an evaporation process and is discarded. Finally, the scheme adopts fixed evaporation crystallization parameters to operate, cannot adapt to fluctuation of incoming material water quality and waste heat supply, and has poor system operation stability, unstable product purity and low overall energy efficiency. These drawbacks limit the practical application of this technique in the production of lithium iron phosphate. Disclosure of Invention In order to solve the technical problems, the invention aims to provide a device and a method for comprehensively utilizing waste water and waste heat in the production of positive electrode materials, the device for comprehensively utilizing the waste water and the waste heat in the production of the positive electrode materials is provided with an independent sand mill waste water and spray drying waste water special line treatment system, meanwhile, the deep integration of the heat pump system and the spray drying process is introduced, and a feedback control system based on the real-time monitoring of the mixed waste gas state is established, so that the comprehensive utilization of the waste water and the preheating generated in the production process of the anode material is realized. To achieve the purpose, the invention adopts the following technical scheme: The invention provides a comprehensive utilization device of waste water and waste heat in the production of positive electrode materials, which comprises a main system and an auxiliary system, wherein the main system