New energy battery lithium salt production wastewater treatment system

Abstract

The invention relates to the technical field of water treatment, discloses a new energy battery lithium salt production wastewater treatment system, and aims to solve the technical problems of large wastewater treatment operation investment and slow reaction rate. The power supply assembly is electrically connected with the electrode assembly through a wire; the membrane separation unit comprises a multi-stage membrane assembly, the multi-stage membrane assembly is provided with a permeable water end and a concentrated water end, and the multi-stage membrane assembly is connected with the water outlet end of the electrocoagulation unit through a pipeline; the supercritical oxidation unit comprises a pressurizing and heating assembly and a reaction pipeline, and the pressurizing and heating assembly is connected with the concentrated water end of the membrane separation unit through a pipeline; the solid-liquid separation unit comprises a crystallizer and a solid-liquid separator, and the crystallizer is connected with the water outlet end of the supercritical oxidation unit; and the control unit comprises a monitoring sensor group and a controller.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment, and particularly relates to a new energy battery lithium salt production wastewater treatment system. BACKGROUND

[0002] The main components of new energy battery lithium salt production wastewater are triethylamine, fluoride, dichloromethane, acetonitrile, cyanide, chloride, LAS and sulfate, and the wastewater belongs to high-concentration organic wastewater which is difficult to be biodegraded. The Fenton reagent method is usually used for advanced oxidation to treat the high-concentration organic wastewater, but a large amount of acid and alkali need to be added in the method, and therefore new salt substances are formed in the treatment process, and the formed salt substances need to be treated subsequently, which increases the treatment load, and the wastewater treatment operation requires a large investment and has a slow reaction rate. SUMMARY

[0003] The application provides a new energy battery lithium salt production wastewater treatment system to solve the technical problems of a large wastewater treatment operation investment and a slow reaction rate.

[0004] The technical scheme adopted by the application is as follows: A new energy battery lithium salt production wastewater treatment system comprises, in sequence, an electric coagulation unit, a membrane separation unit, a supercritical oxidation unit, a solid-liquid separation unit, a control unit, a pipe and valve group and a support frame. The electric coagulation unit comprises an electrode assembly and a power supply assembly, the electrode assembly is arranged in an electric coagulation reactor, and the power supply assembly is electrically connected to the electrode assembly through a wire. The membrane separation unit comprises a multistage membrane assembly, the multistage membrane assembly is provided with a permeate water end and a concentrated water end, and the multistage membrane assembly is connected to a water outlet end of the electric coagulation unit through a pipeline. The supercritical oxidation unit comprises a pressurizing and heating assembly and a reaction pipeline, the pressurizing and heating assembly is connected to the concentrated water end of the membrane separation unit through the pipeline. The solid-liquid separation unit comprises a crystallizer and a solid-liquid separator, and the crystallizer is connected to a water outlet end of the supercritical oxidation unit. The control unit comprises a monitoring sensor group and a controller, the monitoring sensor group is distributed at inlets and outlets of the respective treatment units, and the controller is electrically connected to the power supply assembly, the pressurizing and heating assembly and a pump group. The pipe and valve group connects water inlets and outlets of the respective treatment units. The support frame is used for mounting the electric coagulation unit, the membrane separation unit, the supercritical oxidation unit, the solid-liquid separation unit and the control unit.

[0005] Optionally, the multistage membrane assembly comprises a reverse osmosis membrane assembly and / or an electrodialysis membrane assembly, and the reverse osmosis membrane assembly and / or the electrodialysis membrane assembly are arranged in series.

[0006] Optionally, the pressurizing and heating assembly comprises a booster pump and a heater, and the booster pump and the heater are arranged in the pipeline in sequence.

[0007] Optionally, the crystallizer of the solid-liquid separation unit is one of an evaporation crystallizer or a vacuum crystallizer, and the vacuum crystallizer is connected to the solid-liquid separator through a pipeline.

[0008] Optionally, the electrode assembly is an anode plate and a cathode plate arranged in parallel in the electrocoagulation reactor, and the power supply assembly is electrically connected to the anode plate and the cathode plate through wires.

[0009] Optionally, the controller is configured to automatically adjust the output power of the power supply assembly and the temperature of the pressurizing and heating assembly according to the signals collected by the monitoring sensor group, and control the start and stop of the pump group.

[0010] Optionally, the support frame includes a base and a stand column, and the stand column is provided with a mounting platform for sequentially supporting the electrocoagulation unit, the membrane separation unit, the supercritical oxidation unit and the solid-liquid separation unit.

[0011] As the above technical solutions are adopted, the application has the following beneficial effects: 1. The electrocoagulation unit generates metal flocs spontaneously by using electrochemical principle, without adding acid, alkali or metal salt, and removes a large amount of secondary salts generated due to excessive addition of reagents in the traditional Fenton method, thereby reducing the salt content of waste liquid and significantly reducing the subsequent treatment load compared with traditional chemical precipitation; 2. The multi-stage membrane separation unit effectively separates ion components, and the supercritical oxidation module mineralizes the refractory organic matter, which helps to achieve strict recycling or discharge standards; 3. The solid-liquid separation unit recycles solid salts, and the evaporation tail gas condensate water and the membrane permeate water are combined and recycled, thereby maximizing the use of water resources and reducing waste discharge; 4. The zero liquid discharge mode meets the environmental protection requirements, and through resource recycling and energy consumption optimization, economic and environmental benefits are achieved. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings described herein are used to provide a further understanding of the application, form a part of the application, and the illustrative embodiments of the application and their descriptions are used to explain the application, and do not constitute an improper limitation on the application. In the drawings: Figure 1 is a structural schematic diagram of the application. DETAILED DESCRIPTION

[0013] In order to more clearly explain the overall concept of the application, the following will be described in detail in an exemplary manner with reference to the drawings.

[0014] Many particular details are set forth in the following description in order to provide a thorough understanding of the application. However, the application can be practiced according to other embodiments that can not be specifically described in the description. Furthermore, the description can not include all possible embodiments of the application. It is intended that the description be understood as including all such embodiments.

[0015] A new energy battery lithium salt production wastewater treatment system, comprising sequentially connected: The electric coagulation unit comprises an electrode assembly and a power supply assembly. The electrode assembly is arranged in the electric coagulation reactor, and the power supply assembly is electrically connected to the electrode assembly through a wire. The membrane separation unit comprises a multi-stage membrane assembly. The multi-stage membrane assembly is provided with a permeate water end and a concentrated water end. The multi-stage membrane assembly is connected to the water outlet end of the electric coagulation unit through a pipeline. The supercritical oxidation unit comprises a pressurizing and heating assembly and a reaction pipeline. The pressurizing and heating assembly is connected to the concentrated water end of the membrane separation unit through a pipeline. The solid-liquid separation unit comprises a crystallizer and a solid-liquid separator. The crystallizer is connected to the water outlet end of the supercritical oxidation unit. The control unit comprises a monitoring sensor group and a controller. The monitoring sensor group is distributed at the inlets and outlets of the various treatment units. The controller is electrically connected to the power supply assembly, the pressurizing and heating assembly, and the pump group. The pipeline and valve group connects the water inlets and outlets of the various treatment units. The support frame is used to mount the electric coagulation unit, the membrane separation unit, the supercritical oxidation unit, the solid-liquid separation unit, and the control unit.

[0016] The wastewater to be treated is introduced into the electric coagulation reactor through a water inlet pump. Two iron plates and a copper plate are arranged in the reaction cavity as the electrode assembly. No additional chemical agent is used. After power supply, the power supply assembly outputs a direct current electric field. Suspended solids and part of the ions in the wastewater dissolve and release metal ions in the iron plate, combine with sols to form flocs, and settle. The turbidity of the water outlet end of the electric coagulation unit decreases from about 500 NTU to about 50 NTU. Part of the fluoride and cyanide is also removed.

[0017] Further, the multi-stage membrane assembly comprises a reverse osmosis membrane assembly and / or an electrodialysis membrane assembly, which are arranged in series.

[0018] The water outlet of the electric coagulation unit is used as the water inlet of the membrane separation unit, which is subjected to desalination wastewater treatment through the multi-stage reverse osmosis membrane assembly and / or the electrodialysis membrane assembly.

[0019] The water permeated from the reverse osmosis membrane assembly and / or the electrodialysis membrane assembly is permeate water, which has a significantly reduced salt and organic matter content and can be directly used as circulating water. The high-concentration salt and organic matter solution trapped in the reverse osmosis membrane assembly and / or the electrodialysis membrane assembly is concentrated water, which is further sent to the supercritical oxidation unit for deep mineralization. The ion content in the concentrated water increases from the initial 8,000 mg / L to about 30,000 mg / L.

[0020] Further, the pressurizing and heating assembly comprises a booster pump and a heater, which are arranged in the supercritical oxidation unit inlet pipeline in sequence.

[0021] The concentrated water from the membrane separation unit is sent to the booster pump, pressurized, and then enters the heater, and is heated to above 374 ℃, so that the oxidation reaction is carried out under supercritical conditions. The refractory organic matter and cyanide in the wastewater are rapidly mineralized in the high-temperature and high-pressure environment. After the reaction, the product flows through the pressure relief pipeline to release pressure to the normal pressure state, and the temperature is cooled to below 50 ℃, and then enters the next unit.

[0022] Further, the crystallizer of the solid-liquid separation unit is one of an evaporation crystallizer or a vacuum crystallizer, and the vacuum crystallizer is connected to the solid-liquid separator through a pipeline.

[0023] After the water from the supercritical oxidation unit enters the vacuum crystallizer, the remaining water is evaporated and separated by using the phase change principle under vacuum conditions, and solid salts such as calcium fluoride and sodium chloride are precipitated, which are automatically unloaded and collected by a screw conveying device, and the tail gas of the evaporation tower is condensed to recover pure water.

[0024] In other embodiments, the crystallizer of the solid-liquid separation unit can also be an evaporation crystallizer.

[0025] Further, the electrode assembly is an anode plate and a cathode plate arranged in parallel in the electrocoagulation reactor, and the power supply assembly is electrically connected to the anode plate and the cathode plate through wires.

[0026] Further, the controller is configured to automatically adjust the output power of the power supply assembly and the temperature of the pressurizing and heating assembly according to the signals collected by the monitoring sensor group, and to control the start and stop of the pump group.

[0027] Temperature sensors, conductivity sensors, and pressure sensors are arranged at the inlet and outlet positions of each treatment unit, and the sensor signals are transmitted in real time to the programmable controller. The controller automatically adjusts the voltage output of the power supply assembly according to the conductivity change at the inlet and outlet, adjusts the temperature set point of the pressurizing and heating assembly, and starts and stops each pump group, so as to realize online closed-loop control of the parameters of each unit.

[0028] Further, the support frame comprises a base and a column, and the column is provided with a mounting platform for sequentially supporting the electrocoagulation unit, the membrane separation unit, the supercritical oxidation unit, and the solid-liquid separation unit.

[0029] All unit components are installed on the support frame composed of steel structure base and upper and lower columns, and the installation platform height is increased in turn, facilitating gravity-assisted discharge and pipeline simplification. The frame is provided with unified grounding, vibration isolation device and maintenance channel.

[0030] During the entire operation process, the wastewater to be treated sequentially passes through four units of electrocoagulation, membrane separation, supercritical oxidation and solid-liquid separation. The electrocoagulation unit removes suspended solids and part of ions through electrochemical action to reduce the load of the subsequent membrane separation unit. The membrane separation unit realizes desalination and concentration, and separates pure water and high-concentration ionic liquid which can be recycled. The supercritical oxidation unit rapidly mineralizes organic and refractory components in a supercritical water environment. The solid-liquid separation unit separates residual water from salts to obtain recyclable solid salt and pure water.

[0031] The system is provided with an intermediate pool for collecting permeate water in the multi-stage reverse osmosis membrane assembly and / or the electrodialysis membrane assembly and the pure water recovered after condensation of the tail gas of the evaporation tower. The two water sources are homogenized by mechanical stirring or circulating pumps in the intermediate pool and then supplied as circulating water or general process make-up. In order to ensure the water quality of the mixed water, conductivity and TOC online analyzers are arranged at the inlet and outlet of the mixing pool to monitor the salinity and organic matter concentration in real time. Only when the indicators meet the process requirements, the controller allows the release to the downstream system.

[0032] The control unit monitors and adjusts the operating parameters of each module in real time, the pipeline and valve group realize process switching and system maintenance, and the support frame ensures the stability of the overall structure and the convenience of installation. The entire system is mainly driven by electric energy and a small amount of auxiliary gas, without the need for large amounts of chemical reagent addition, and achieves efficient, energy-saving and near-zero emission wastewater treatment effect.

[0033] The places not described in the application can be realized by using or referring to the existing technology.

[0034] Each embodiment in the specification is described in a progressive manner, and the same and similar parts between each embodiment can be referred to each other. Each embodiment mainly describes the differences from other embodiments.

[0035] The above only describes the embodiments of the application and is not intended to limit the application. The application can have various changes and modifications for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the scope of the claims of the application.

Claims

1. A wastewater treatment system for lithium salt production in new energy batteries, characterized in that, Including those connected sequentially: Electrocoagulation unit: includes electrode assembly and power supply assembly. The electrode assembly is set inside the electrocoagulation reactor, and the power supply assembly is electrically connected to the electrode assembly through wires. Membrane separation unit: includes multi-stage membrane modules, each having a permeate end and a concentrate end, and is connected to the outlet end of the electrocoagulation unit via a pipeline; Supercritical oxidation unit: includes a pressurized heating assembly and reaction pipeline, and the pressurized heating assembly is connected to the concentrated water end of the membrane separation unit through a pipeline; Solid-liquid separation unit: includes a crystallizer and a solid-liquid separator, the crystallizer being connected to the outlet of the supercritical oxidation unit; Control unit: includes a monitoring sensor group and a controller. The monitoring sensor group is distributed at the inlet and outlet of each processing unit, and the controller is electrically connected to the power supply component, the pressurization and heating component and the pump group respectively. Piping and valve assembly: connects the inlet and outlet ports of each treatment unit; Support frame: used to install the electrocoagulation unit, membrane separation unit, supercritical oxidation unit, solid-liquid separation unit and control unit.

2. The system according to claim 1, characterized in that: The multi-stage membrane module includes a reverse osmosis membrane module and / or an electrodialysis membrane module, which are arranged in series.

3. The system according to claim 1, characterized in that: The pressurized heating assembly includes a booster pump and a heater, which are arranged sequentially in the inlet pipeline of the supercritical oxidation unit.

4. The system according to claim 1, characterized in that: The crystallizer of the solid-liquid separation unit is either an evaporation crystallizer or a vacuum crystallizer, and the vacuum crystallizer is connected to the solid-liquid separator via a pipeline.

5. The system according to claim 1, characterized in that: The electrode assembly consists of an anode plate and a cathode plate arranged in parallel within the electrocoagulation reactor, and the power supply assembly is electrically connected to the anode plate and the cathode plate via wires.

6. The system according to claim 1, characterized in that: The controller is configured to automatically adjust the output power of the power supply component and the temperature of the pressurized heating component based on the signals collected by the monitoring sensor group, and control the start and stop of the pump group.

7. The system according to claim 1, characterized in that: The support frame includes a base and a column. The column is equipped with an installation platform for sequentially supporting the electrocoagulation unit, the membrane separation unit, the supercritical oxidation unit, and the solid-liquid separation unit.

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