CN-121800381-B - Intelligent impurity removal concentration system for lithium-containing solution and self-adaptive control method thereof

CN121800381BCN 121800381 BCN121800381 BCN 121800381BCN-121800381-B

Abstract

The invention relates to the technical field of industrial wastewater treatment, in particular to an intelligent impurity removal concentration system of lithium-containing solution and a self-adaptive control method thereof, wherein the system is sequentially provided with a plurality of step impurity removal units along the water flow direction, three sensors of pressure, high-frequency pulsation and ultrasonic are integrated by a high-pressure reverse osmosis unit, pressure difference, hydraulic pulsation and membrane surface reflection echo signals in a section are respectively obtained, a controller adopts weighted fuzzy entropy fusion to generate membrane interface scaling potential energy, and dual-mode self-adaptive control is automatically executed according to the comparison result of the scaling potential energy and a threshold value, namely the maximum membrane section of the positioning potential energy is subjected to sectional differential adjustment under the risk trend; and under the safety trend, after the duration time is confirmed, the pump frequency or the reflux gear is gradually reduced in an optimized mode, and potential energy dynamic recovery is continuously monitored. The invention realizes quantitative prediction and accurate intervention of scaling risk, and simultaneously digs energy-saving potential while actively preventing scale, thereby remarkably improving system stability and prolonging the service life of the membrane element.

Inventors

YANG LEI
LIU TINGTING
HUANG YANJUN
Su Zhanli

Assignees

莱特莱德(上海)技术有限公司

Dates

Publication Date: 20260508
Application Date: 20260310

Claims (9)

1. An intelligent impurity removal concentration self-adaptive control method for lithium-containing solution is characterized by comprising the following steps: Obtaining inlet and outlet pressures corresponding to each section of membrane assembly respectively so as to determine the pressure difference in each section of membrane assembly; Respectively acquiring a high-frequency pressure pulsation signal and a reflection echo signal of a membrane interface adjacent area of each section of membrane assembly, wherein the high-frequency pressure pulsation signal comprises a first high-frequency pressure pulsation signal and a second high-frequency pressure pulsation signal; calculating the change rate of the viscosity coefficient of the fluid near the membrane surface corresponding to each section of membrane component based on the reflected echo signals; Based on the calculus change of the pressure difference in the sections of the membrane components of each section, the viscosity coefficient change rate and the spectrum characteristics of the high-frequency pressure pulsation signal, determining the scaling potential of the membrane interface by adopting a weighted fuzzy entropy calculation method, and specifically comprises the following steps: Constructing a first characteristic sequence, a second characteristic sequence and a third characteristic sequence based on the viscosity coefficient change rate, the calculus change of the pressure difference in the section and the spectral characteristics of the high-frequency pressure pulsation signal respectively; Calculating fuzzy entropy of the first feature sequence, the second feature sequence and the third feature sequence respectively, sequentially setting weight coefficients w1, w2 and w3, weighting and calculating fusion entropy values, determining the minimum possible value and the maximum possible value of the fusion entropy through historical data or experiments, and carrying out normalized mapping on the fusion entropy values to the [0,100] interval to obtain membrane interface scaling potential energy; wherein w1+w2+w3=1, the value range of w1 is 0.3-0.4, the value range of w2 is 0.4-0.6, and the value range of w3 is 0.1-0.2; determining a membrane interface scaling trend according to the magnitude relation of the membrane interface scaling potential and the scaling potential threshold, comprising: Responding to the membrane interface scaling trend as scaling risk trend, determining a target membrane section according to the membrane interface scaling potential energy, and performing sectional differential adjustment based on the target membrane section position; Responding to the membrane interface scaling trend as scaling safety trend, and carrying out energy-saving optimization adjustment on the running frequency of the inter-section booster pump or the concentrated water backflow gear; The intelligent impurity removal concentration self-adaptive control method of the lithium-containing solution is applied to an intelligent impurity removal concentration system of the lithium-containing solution, and comprises a coagulation air floatation oil removal unit, a coagulation sedimentation unit, a multi-medium filter unit, an ultrafiltration unit, an oil removal filter unit, a resin ion exchange unit and a high-pressure reverse osmosis unit which are connected through pipelines in sequence along the water flow direction; the high-pressure reverse osmosis unit comprises at least two sections of membrane assemblies, a booster pump and a concentrated water return pipeline, wherein the booster pump and the concentrated water return pipeline are positioned between adjacent membrane assemblies, and the high-pressure reverse osmosis unit further comprises: the pressure sensor group is arranged at the inlet and outlet of each section of membrane component and used for acquiring the inlet and outlet pressure of each section and the pressure difference in each section; The pulsation sensor group is used for acquiring high-frequency pressure pulsation signals and comprises a first high-frequency pressure pulsation sensor arranged at an inlet and an outlet of the interstage booster pump and a second high-frequency pressure pulsation sensor arranged at a collection node of the concentrated water return pipeline; The ultrasonic sensor group for acquiring the reflected echo signals comprises micro-flow field ultrasonic sensors which are respectively arranged in the adjacent areas of the membrane interfaces of the membrane assemblies of each section; and the controller is respectively connected with the pressure sensor group, the pulsation sensor group and the ultrasonic sensor group through signals and is used for generating membrane interface scaling potential energy representing the membrane interface scaling trend according to the reflection echo signal, the intra-segment pressure difference and the high-frequency pressure pulsation signal so as to adaptively adjust the running frequency of the inter-segment booster pump and/or the back flow gear of the concentrate.
2. The method for adaptively controlling the intelligent impurity removal concentration of a lithium-containing solution according to claim 1, wherein the process of calculating the change rate of the viscosity coefficient of the fluid near the surface of the membrane comprises: and extracting at least one echo characteristic quantity of the reflected echo signal in a preset sampling period, and determining the change rate of the echo characteristic quantity in a time sequence dimension as the change rate of the viscosity coefficient.
3. The intelligent impurity removal concentration self-adaptive control method for the lithium-containing solution according to claim 1, wherein the spectral characteristics of the high-frequency pressure pulsation signal comprise pressure pulsation energy spectral distribution, dominant frequency components and spectral peak width; wherein the calculus variation of the differential pressure in the segment comprises a first order variation rate and a second order variation rate of the differential pressure in the segment.
4. The method for adaptively controlling intelligent impurity removal and concentration of lithium-containing solution according to claim 1, wherein a membrane interface scaling trend is determined according to a magnitude relation between the membrane interface scaling potential and a scaling potential threshold, wherein: determining that the membrane interface structure trend is a scaling risk trend in response to the membrane interface scaling potential being greater than a scaling potential threshold; and determining that the membrane interface structure trend is a scaling safety trend in response to the membrane interface scaling potential being less than or equal to the scaling potential threshold.
5. The method according to claim 4, wherein the membrane segment component with the largest membrane interface scaling potential is determined as a target membrane segment in response to the membrane interface scaling trend being a scaling risk trend, and the segment differential adjustment is performed based on the target membrane segment position.
6. The method for adaptively controlling intelligent impurity removal and concentration of lithium-containing solution according to claim 5, wherein the step of performing the step-wise differential adjustment based on the target membrane segment position comprises the steps of: responding to the target membrane section as a rear section membrane component, and improving the running frequency of the inter-section booster pump; and in response to the target membrane section being a front section membrane assembly, limiting the concentrated water backflow gear to inhibit the concentration polarization aggravation of the front section membrane interface.
7. The method of claim 6, wherein increasing the operating frequency of the inter-stage booster pump comprises: Determining a current pressure pulsation intensity based on the high-frequency pressure pulsation signal; Comparing the current pressure pulsation intensity with a preset pressure pulsation intensity range, wherein: If the current pressure pulsation intensity is lower than a preset pressure pulsation intensity range, overlapping low-frequency pulsation modulation on the basis of increasing the gear so that the pulsation intensity enters the range; And if the current pressure pulsation intensity is higher than the preset pressure pulsation intensity range, increasing the gear in a stepped frequency-increasing mode to inhibit pulsation intensity overshoot.
8. The method of claim 4, wherein the process of energy-saving optimization adjustment of the inter-stage booster pump operating frequency or the concentrate return shift in response to the scaling safety trend comprises: Determining the duration of the fouling safety trend; Based on the fact that the duration time is longer than or equal to the preset duration time, the operation frequency of the inter-section booster pump and/or the concentrated water backflow gear are/is reduced step by step; and continuously calculating the scaling potential of the membrane interface, stopping the downshift in response to the scaling potential of the membrane interface exceeding the scaling potential threshold, and recovering to the last gear before the downshift is triggered.
9. The intelligent impurity-removing concentration self-adaptive control method for the lithium-containing solution, according to claim 8, is characterized in that the operation frequency of the inter-stage booster pump is gradually reduced according to the judgment result that the water flow rate of the rear-stage product is larger than or equal to the lower limit of the water flow rate; Otherwise, the concentrated water reflux gear is gradually reduced.

Description

Intelligent impurity removal concentration system for lithium-containing solution and self-adaptive control method thereof Technical Field The invention relates to the technical field of industrial wastewater treatment, in particular to an intelligent impurity removal concentration system for lithium-containing solution and a self-adaptive control method thereof. Background With the rapid development of new energy industry, the demand for lithium resources is rapidly increasing, and the extraction of lithium from lithium-containing brine, mine drainage or waste battery leaching liquid becomes an important channel. The waste water is generally complex in composition, and contains high-value lithium (such as 2000-3000 mg/L), high-concentration chloride ions (12-17 g/L), various scaling ions (Ca 2+、Mg2+、SO42-、PO43-、F-、SiO2), metal ions (Al 3+、Fe3+), organic matters and oil components. At present, the concentration of lithium-containing solution by adopting a high-pressure reverse osmosis membrane method is a key means for improving the lithium recovery efficiency. However, when the complex water quality is treated, the direct application of the membrane method has serious challenges that firstly, the high-concentration scaling ions are extremely easy to exceed the solubility product under the high-pressure concentration environment, hard scales such as calcium sulfate, calcium fluoride, silicon scale and the like are formed on the surface of the membrane, so that membrane elements are irreversibly damaged, secondly, residual organic matters and emulsified oil can be adsorbed on the surface of the membrane or block membrane holes, so that the flux is rapidly reduced, and thirdly, the high-concentration chloride ions can generate oxidative degradation risks on membrane materials under the high pressure and specific conditions, so that the system cannot stably operate for a long time. In order to ensure the safe operation of a membrane system, the prior art develops various pretreatment methods, but the prior art has the limitations that the conventional coagulating sedimentation can remove suspended matters and partial heavy metal ions, but has limited capability of removing soluble silicon, fluorine and low-concentration hardness ions, and is especially ineffective for emulsified oil and surfactants, the medium filtration can only intercept particulate matters and can not remove colloid and soluble organic matters, the ion exchange resin can deeply remove hardness, but is extremely easy to be polluted by the organic matters and oil residues left in the front section to cause poisoning, the exchange capacity is rapidly attenuated in a short period, the regeneration is frequent and the cost is high, the conventional pretreatment and reverse osmosis combined process is mainly simple series connection of independent units, and each unit lacks synergy, so that the failure of one unit often causes the linkage collapse of the whole system. In view of this, the prior art lacks an integrated process that can systematically and stepwisely thoroughly remove various membrane pollution risk substances, and can perform real-time sensing and self-adaptive regulation and control on the operation state of a core concentration unit (high-pressure reverse osmosis), so as to provide long-term stability, low energy consumption and intelligent guarantee for efficient recovery of lithium resources. Disclosure of Invention Therefore, the invention provides an intelligent impurity removal concentration system of a lithium-containing solution and a self-adaptive control method thereof, and provides an intelligent lithium-containing solution treatment system capable of sensing the scaling trend in advance based on multi-source data fusion, positioning a risk membrane section, and self-adaptively executing sectional differential regulation and energy-saving optimization and a control method thereof, aiming at the problems that scaling risks are difficult to quantitatively predict in real time, inter-section supercharging and concentrated water backflow regulation lack accurate coordination, and scaling prevention and energy-saving operation modes cannot be dynamically balanced in the conventional lithium-containing solution high-pressure reverse osmosis system in operation. In order to achieve the above objective, in one aspect, the present invention provides an intelligent impurity removal and concentration system for lithium-containing solution, which sequentially includes, along a water flow direction, a coagulation air flotation degreasing unit, a coagulation sedimentation unit, a multi-medium filter unit, an ultrafiltration unit, a degreasing filtration unit, a resin ion exchange unit, and a high-pressure reverse osmosis unit, wherein the high-pressure reverse osmosis unit includes at least two sections of membrane assemblies, a booster pump located between adjacent membrane assemblies, and a concentrated water return pipeline, and f