A method and system for measuring and correcting the quality and salinity of water for desalination

Abstract

The present application relates to the technical field of salinity determination, in particular to a water quality salinity determination correction method and system for seawater desalination. The method comprises: obtaining the conductivity of each sensor on both sides of the RO component, the water outlet side pressure and the salinity in the seawater desalination process; for each sensor, according to the similar situation of the conductivity change characteristics of each period in the historical period and the current period and the fluctuation difference of the conductivity of the historical period and the current period, the matching period is screened; the Kalman filter gain when the conductivity is denoised is adjusted in combination with the conductivity of the current period and the matching period, and the conductivity is filtered; according to the conductivity of the sensors on the water inlet side and the water outlet side, the corrected conductivity and the water outlet side pressure, the pollution degree is obtained, the salinity determination interference index is determined in combination with the level of the RO component, and the Kalman filter gain when the salinity is denoised is adjusted, and the salinity is filtered. The present application improves the accuracy of salinity determination.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of salinity determination, in particular to a water quality salinity determination correction method and system for seawater desalination. BACKGROUND

[0002] Seawater desalination is a process of removing salt and impurities in seawater and converting it into fresh water for human use. The process of seawater desalination is as follows: pretreatment of raw seawater, including coagulation sedimentation, medium filtration, sterilization and algae removal, transmission of pretreated seawater to a reverse osmosis desalination system, overcoming of osmotic pressure of seawater, separation of water and salt and other impurities through a reverse osmosis membrane, post-treatment (RO water, mineralization adjustment, etc.), and output of product water and concentrated brine. When determining the salinity of the seawater desalination process, sensors need to be set at key steps in the seawater desalination process to monitor the water quality, so as to determine the salinity.

[0003] The existing salinity determination method of the seawater desalination system cannot timely capture the water quality fluctuation in the seawater desalination process, so that the determination result of the water quality salinity in the desalination process is not accurate. For example, the salinity change of the raw seawater inlet and the influence of the RO component pollution degree in the desalination process may cause the water quality parameter to fluctuate, and may interfere with the sensor detection result, thereby affecting the accuracy of the salinity determination. SUMMARY

[0004] In order to solve the problem of inaccurate determination result in the process of determining the water quality salinity by the existing method, the purpose of the present application is to provide a water quality salinity determination correction method and system for seawater desalination, and the technical solution adopted is as follows:

[0005] In the first aspect, the present application provides a water quality salinity determination correction method and system for seawater desalination, which comprises the following steps:

[0006] The conductivity, outlet side pressure and salinity of each sensor on both sides of the RO component in the seawater desalination process are obtained. The seawater desalination process includes a plurality of historical periods and a current period, each period contains a plurality of time periods, and the current time period is the time period in which the current time is located;

[0007] For each sensor, according to the similarity of the conductivity change characteristics of each time period in the historical period and the current time period and the fluctuation difference of the conductivity between the historical period and the current period, the matching time period of the current time period in each historical period is selected; the Kalman filter gain is adjusted when the conductivity is denoised, and the conductivity is filtered to obtain the corrected conductivity, combined with the conductivity of all time points in the current time period and the fluctuation difference of the conductivity between the current time period and the period in which the matching time period is located;

[0008] According to the conductivity of the sensors on the water inlet side and the water outlet side of the RO component, the corrected conductivity, and the pressure on the water outlet side, the pollution degree of the RO component at each moment is obtained; combined with the pollution degree and the level of the RO component, the salt determination interference index corresponding to the RO component is determined;

[0009] Based on the salt determination interference index, the Kalman filter gain for salt denoising is adjusted, and the corrected salinity is obtained by filtering the salinity.

[0010] Preferably, the similarity of the change characteristics of the conductivity of each period in the historical period and the current period and the fluctuation difference of the conductivity of the historical period and the current period are used to screen the matching period of the current period in each historical period, including:

[0011] For any period:

[0012] The ratio between the range of the conductivity of all moments in the period and the length of the period is recorded as the conductivity feature value of the period;

[0013] According to the difference between the conductivity feature value of the current period and each period in the historical period, the conductivity fluctuation similarity index of the current period and each period in the historical period is obtained;

[0014] For any historical period: the period corresponding to the maximum conductivity fluctuation similarity index of the current period in the historical period is taken as the matching period of the current period in the historical period.

[0015] Preferably, the Kalman filter gain for conductivity denoising is adjusted by combining the conductivity of all moments in the current period and the fluctuation difference of the conductivity of the current period and the period where the matching period is located, including:

[0016] For any sensor:

[0017] The DTW distance between the conductivity curve of each historical period and the conductivity curve of the current period is calculated respectively, wherein the conductivity curve of each period is obtained by curve fitting the conductivity of all moments in the period;

[0018] The first average value of the conductivity of all moments in each matching period is calculated respectively; the product of the DTW distance between the conductivity curve of the period where each matching period is located and the conductivity curve of the current period and the corresponding first average value is recorded as the first product corresponding to each matching period; the average value of the first products corresponding to all matching periods is taken as the predicted mean value of the conductivity of the current period;

[0019] Calculate the difference between the conductivity of each time point in the current period and the average of the conductivity prediction as the first difference value corresponding to each time point in the current period; Calculate the average of the first difference value corresponding to all time points in the current period; The sum of the conductivity of each time point in the current period and the average of the first difference value is used as the prediction value of each time point in the current period;

[0020] The difference between the conductivity of each time point in the current period and the corresponding prediction value is used as the difference index of each time point.

[0021] According to the DTW distance between the conductivity curve of any sensor and the remaining sensors in the current period, and the difference index, the error factor of the any sensor at the current time is obtained.

[0022] The Kalman filter gain is adjusted when the conductivity is denoised using the error factor.

[0023] Preferably, the error factor of the any sensor at the current time is obtained according to the DTW distance between the conductivity curve of the any sensor and the remaining sensors in the current period, and the difference index, comprising:

[0024] Calculate the average of the DTW distance between the conductivity curve of the any sensor and the remaining sensors in the current period;

[0025] Calculate the first ratio between the difference index at the current time and the average difference index of all time points in the current period;

[0026] The product of the average of the DTW distance and the first ratio is determined as the error factor of the any sensor in the current period.

[0027] Preferably, the Kalman filter gain is adjusted when the conductivity is denoised using the error factor, comprising:

[0028] The difference between the constant 1 and the error factor is used as the first adjustment coefficient;

[0029] The product between the first adjustment coefficient and the initial gain of the Kalman filter when the conductivity is denoised is used as the adjusted Kalman filter gain.

[0030] Preferably, the pollution degree of the RO assembly at each time point is obtained according to the conductivity of the sensors on the water inlet side and the water outlet side of the RO assembly, the corrected conductivity, and the water outlet side pressure, comprising:

[0031] For any time point:

[0032] calculating a second ratio between the corrected conductivity of the RO assembly inlet-side sensor at the any moment and the corresponding conductivity, and a third ratio between the corrected conductivity of the RO assembly outlet-side sensor and the corresponding conductivity;

[0033] obtaining the contamination degree of the RO assembly at the any moment according to the product of the second ratio and the third ratio, the difference between the second ratio and the third ratio, and the outlet-side pressure, wherein the product of the second ratio and the third ratio, the outlet-side pressure and the contamination degree are positively correlated, and the difference between the second ratio and the third ratio and the contamination degree are negatively correlated.

[0034] Preferably, the method further comprises:

[0035] taking the difference between the contamination degree at the current moment and the contamination degree after the last flush at the current moment as the contamination degree growth amplitude;

[0036] obtaining the salt determination interference index of the RO assembly according to the contamination degree after the last flush at the current moment, the contamination degree growth amplitude, the level of the assembly and the time interval between the current moment and the last flush at the current moment.

[0037] Preferably, the method further comprises:

[0038] calculating a second product between the contamination degree after the last flush at the current moment and the contamination degree growth amplitude, and a third product between the level of the RO assembly and the time interval between the current moment and the last flush at the current moment;

[0039] determining the ratio between the second product and the third product as the salt determination interference index of the RO assembly.

[0040] Preferably, the method further comprises:

[0041] calculating a second difference between the constant 1 and the salt determination interference index;

[0042] taking the product between the second difference and the initial gain of the Kalman filter for the salt determination interference index as the adjusted Kalman filter gain.

[0043] In a second aspect, the present application provides a water quality salinity measurement correction system for seawater desalination, which implements the method described above, and comprises:

[0044] A data acquisition module is configured to acquire the conductivity of each sensor on both sides of the RO component, the pressure on the water outlet side, and the salinity during the seawater desalination process.

[0045] A first correction module is configured to, for each sensor, screen the matching time period of the current time period in each historical period according to the similar variation characteristics of the conductivity of each time period in the historical period and the current time period and the fluctuation difference of the conductivity between the historical period and the current period.

[0046] A calculation module is configured to obtain the contamination degree of the RO component at each time point according to the conductivity of the sensors on the water inlet side and the water outlet side of the RO component and the corrected conductivity and the pressure on the water outlet side.

[0047] A second correction module is configured to adjust the Kalman filter gain when denoising the salinity based on the salinity measurement interference index and obtain the corrected salinity by filtering the salinity.

[0048] The present application has at least the following beneficial effects:

[0049] The present application monitors the conductivity of each sensor on both sides of the RO component, the pressure on the water outlet side, and the salinity during the seawater desalination process. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, and the advantages thereof, a brief introduction will be given to the drawings required in the description of the embodiments or the prior art. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0051] Figure 1 A flowchart of a seawater desalination water quality salinity determination correction method and system provided by an embodiment of the present application;

[0052] Figure 2 A structural block diagram of a seawater desalination water quality salinity determination correction system provided by an embodiment of the present application. DETAILED DESCRIPTION

[0053] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purpose, a seawater desalination water quality salinity determination correction method and system according to the present application are described in detail below in combination with the drawings and preferred embodiments.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0055] The specific scheme of the seawater desalination water quality salinity determination correction method and system provided by the present application is described in detail below in combination with the drawings.

[0056] An embodiment of a seawater desalination water quality salinity determination correction method:

[0057] The specific scenario targeted by the present embodiment is that in the seawater desalination process, water quality salinity data will be affected by various factors when acquired, resulting in the inability to timely capture water quality fluctuations in the seawater desalination process, so that the determination result of water quality salinity in the desalination process is inaccurate. The present embodiment will correct the error detection by combining the correlation degree between sensors corresponding to different seawater desalination steps and the deviation from the predicted value, obtain the pollution degree of the RO component based on the corrected data, correct the salinity determination value according to the pollution degree, and improve the accuracy of the salinity determination result.

[0058] The present embodiment proposes a seawater desalination water quality salinity determination correction method, as shown in Figure 1 The seawater desalination water quality salinity determination correction method of the present embodiment includes the following steps:

[0059] Step S1, obtain the conductivity of each sensor on both sides of the RO component, the pressure on the water outlet side and the salinity in the seawater desalination process; the seawater desalination process includes multiple historical periods and a current period, and each period includes multiple time periods, and the current time period is the time period in which the current time is located.

[0060] First, in the seawater desalination process, an inductive conductivity sensor is arranged on the water inlet side and the water outlet side of the RO component respectively, and the inductive conductivity sensor is used to collect conductivity data. In the embodiment, the collection frequency of the conductivity data is set to 1 time per second, and in specific applications, the implementer can set it according to the specific circumstances. It should be noted that the number of RO components can be more than one, and each RO component has its corresponding level. This embodiment takes one RO component as an example for illustration, and the method provided in this embodiment can be used to process other RO components. At the same time, the pressure on the water outlet side of the RO component in the seawater desalination process is collected.

[0061] In industrial seawater desalination, conductivity is usually used to indirectly measure seawater salinity. Conductivity can reflect the concentration of dissolved salts in seawater. The fluctuation of seawater salinity usually causes certain correlation fluctuation of the conductivity sensor values in different links, so the conductivity values monitored by each conductivity sensor in a short period of time are used to predict the electrolytic rate at the next time.

[0062] The salinity of natural seawater is affected by factors such as season, tide and rainfall, and it changes continuously in a short period of time, that is, the salinity of seawater usually changes according to a certain fluctuation trend in a short period of time.

[0063] Since 12.4 hours is about half of the tidal period of seawater, 12.4 hours is taken as a monitoring period. According to the length of the monitoring period, the seawater desalination process is divided into multiple periods, and the last period in the seawater desalination process is taken as the current period, which includes the current time. All periods before the current period are recorded as historical periods.

[0064] Since multiple sensors are arranged, this embodiment takes one sensor as an example for illustration, and the method provided in this embodiment can be used to process other sensors. Specifically, for any sensor, for any period, the conductivity collected by the sensor at all times in the period is curve-fitted to obtain a maximum point on the curve, and the maximum point is taken as a division point to divide the curve to obtain multiple curve segments, each of which corresponds to a time period, that is, the period is divided into multiple time periods. Each period is divided into multiple time periods by using the method, and the last time period in the current period is recorded as the current time period.

[0065] Step S2, for each sensor, according to the similarity of the change characteristics of the conductivity of each time period in the historical period and the current time period and the fluctuation difference of the conductivity of the historical period and the current period, screening the matching time period of the current time period in each historical period; combining the conductivity of all time points in the current time period and the fluctuation difference of the conductivity of the current time period and the period where the matching time period is located, adjusting the Kalman filter gain when denoising the conductivity, and filtering the conductivity to obtain the corrected conductivity.

[0066] The salinity of seawater usually presents repetitive fluctuation in a short time, such as the salinity increases during the high tide and decreases during the low tide, and the like. Therefore, the time period with similar conductivity fluctuation to the time period where the current time point is located in each historical period is screened, and the similarity of the time series fluctuation of the conductivity measured by the conductivity sensor in each historical period and the current period is combined to predict the conductivity.

[0067] For any time period in the historical period or the current period: the ratio between the range of the conductivity of all time points in the time period and the length of the time period is recorded as the conductivity characteristic value of the time period. By using this method, the conductivity characteristic value of each time period in the historical period and the conductivity characteristic value of each time period in the current period can be obtained.

[0068] Next, one historical period is taken as an example for description, and the method provided in this embodiment can be used to process other historical periods. According to the difference between the conductivity characteristic value of the current time period and the conductivity characteristic value of each time period in the historical period, the conductivity fluctuation similarity index of the current time period and each time period in the historical period is obtained. In this embodiment, the calculation formula of the conductivity fluctuation similarity index is given, and the conductivity fluctuation similarity index of the current time period and the time period in the historical period can be expressed as:

[0069] ;

[0070] Wherein, represents the conductivity fluctuation similarity index of the current time period and the time period in the historical period, represents the conductivity characteristic value of the current time period, represents the conductivity characteristic value of the time period in the historical period, represents the conductivity characteristic value of the time period in the historical period, represents the absolute value symbol.

[0071] represents the difference between the conductivity characteristic value of the current time period and the conductivity characteristic value of the time period in the historical period, and the greater the value is, the greater the difference between the conductivity characteristic values of the two time periods is. In this embodiment, 0.01 is added to the denominator of the calculation formula of the conductivity fluctuation similarity index to prevent the denominator from being 0. In specific application, the implementer can set it according to the specific situation. When the conductivity fluctuation similarity index of the current time period and the time period in the historical period is greater than 0.9, it is considered that the conductivity fluctuation of the current time period is similar to the conductivity fluctuation of the time period in the historical period. The smaller the difference between the conductance characteristic values of the two time periods, the more similar the conductivities in the two time periods, i.e. the greater the conductivity fluctuation similarity index of the current time period with the time period in the historical period.

[0072] For any historical period: the time period in the historical period corresponding to the maximum conductivity fluctuation similarity index with the current time period is taken as the matching time period of the current time period in the historical period. Using this method, the matching time period of the current time period in each historical period can be screened.

[0073] There are fouling, colloids, microorganisms and the like in natural seawater, which can adhere to the electrode surface of the conductivity sensor, and there is a possibility that the measurement sensitivity of the conductivity sensor is interfered to different degrees, and the high-salt and high-pressure environment can cause corrosion of the electrode of the conductivity sensor, resulting in errors in the actual detection value, so it is necessary to correct the measured value of the conductivity sensor in real time based on the fluctuation of the difference between the measured data and the predicted value.

[0074] The data measured by different conductivity sensors have certain relevance, for example, the salinity fluctuation of natural seawater (the fluctuation of the data measured by the conductivity sensor at the original seawater inlet) usually affects the salt load in the entire seawater desalination system, so that the conductivity values on both sides of the RO component exist associated fluctuations.

[0075] For any sensor:

[0076] The conductivity at all times in each period is respectively fitted to obtain the conductivity curve of each period. Curve fitting is prior art and will not be described in detail here. The DTW distance between the conductivity curve of each historical period and the conductivity curve of the current period is calculated, and the calculation method of the DTW distance is prior art and will not be described in detail here.

[0077] The average value of the conductivity at all times in each matching time period is calculated, and the average value is denoted as the first average value; the product of the DTW distance between the conductivity curve of the period where each matching time period is located and the conductivity curve of the current period and the corresponding first average value is denoted as the first product corresponding to each matching time period; and the average value of the first products corresponding to all matching time periods is taken as the predicted average value of the conductivity of the current time period.

[0078] The difference between the conductivity at each time point in the current period and the predicted mean conductivity is calculated, and the difference is recorded as a first difference; the average of the first difference corresponding to all time points in the current period is calculated; and the sum of the conductivity at each time point in the current period and the average of the first difference is taken as the predicted value at each time point in the current period. The difference between the conductivity at each time point in the current period and the corresponding predicted value is taken as the difference index at each time point. If the difference index at each time point is too large, and the addition of the measured data at the current time point causes a sudden change in the correlation degree of the sensor and the remaining conductivity sensors in the period, the measured data of the sensor at the current time point is more likely to have errors.

[0079] According to the DTW distance between the conductivity curves of the sensor and each of the remaining sensors in the current period, and the difference index at the current time point, an error factor of the sensor at the current time point is obtained. Specifically, the average of the DTW distances between the conductivity curves of the sensor and all the remaining sensors in the current period is calculated; the ratio between the difference index at the current time point and the average difference index at all time points in the current period is calculated, and the ratio is recorded as a first ratio; the larger the first ratio, the greater the deviation of the current time point from the predicted conductivity compared to the remaining time points in the period. The product of the average of the DTW distances between the conductivity curves of the sensor and all the remaining sensors in the current period and the first ratio is determined as the error factor of the sensor in the current period. The larger the error factor, the greater the possibility of error of the sensor, and the more it needs to be adjusted, so the Kalman filter gain should be reduced. The difference between the constant 1 and the error factor is taken as a first adjustment coefficient; and the product of the first adjustment coefficient and the initial gain of the Kalman filter for denoising the conductivity is taken as the adjusted Kalman filter gain.

[0080] After determining the adjusted Kalman filter gain, the conductivity collected by the sensor is filtered using the Kalman filter algorithm, and the filtered conductivity is recorded as the corrected conductivity. The Kalman filter algorithm is a prior art, which will not be described in detail here.

[0081] In step S3, the degree of pollution of the RO assembly at each time point is obtained according to the conductivity of the sensors on the water inlet side and the water outlet side of the RO assembly, the corrected conductivity, and the pressure on the water outlet side; and the salt measurement interference index corresponding to the RO assembly is determined in combination with the degree of pollution and the level of the RO assembly.

[0082] In a seawater desalination system, the RO assembly produces water by allowing fresh water to pass through a semi-permeable membrane by intercepting salt, wherein water molecules are pushed through the RO assembly by applying a pressure higher than the osmotic pressure.

[0083] Under normal circumstances, when the desalination capacity of the RO assembly is good, the conductivity of the water production side of the RO assembly should be much lower than that of the water inlet side, and the pressure difference measured on both sides is small. When there is a cumulative pollution in the RO assembly, colloids, microorganisms, salt scale and other pollutants in the original seawater form a dense layer on the membrane surface, hindering ion interception. At this time, the desalination capacity of the RO assembly is weakened, making the salinity of the produced water high, and even the pollution may cause the concentrated water to backflow or locally concentrate, indirectly increasing the conductivity value of the water inlet end of the RO assembly.

[0084] There can be multiple RO assemblies in the seawater desalination system. The present embodiment takes a single RO assembly as an example to analyze the pollution of the RO assembly under the current state based on the corrected conductivity data.

[0085] Based on the above analysis, when the pollution degree of the RO assembly is high, the membrane surface pollution will cause the local salt concentration of the concentrated water side or the backflow to the water inlet end, making the corrected conductivity of the water inlet side high. When the pollution degree is high, the desalination capacity of the RO membrane is disturbed, and the salt cannot be effectively intercepted, making the conductivity of the produced water side high. When the pollution degree is high, the membrane hole is blocked, causing the water flow resistance to increase, and then the outlet water pressure to rise.

[0086] When the conductivity of the water inlet side and the produced water side of the RO assembly measured at a certain moment is higher than that of the original seawater inlet, and the conductivity difference between the two sides is small, and the outlet water pressure measured by the produced water is high, the pollution degree of the RO assembly at that moment is large.

[0087] For any moment:

[0088] Calculate the ratio between the corrected conductivity of the RO assembly inlet side sensor at that moment and the conductivity of the RO assembly inlet side sensor at that moment (initially collected conductivity), and record the ratio as the second ratio. Then, calculate the ratio between the corrected conductivity of the RO assembly outlet side sensor and the conductivity of the RO assembly outlet side sensor, and record the ratio as the third ratio.

[0089] According to the product of the second ratio and the third ratio, the difference between the second ratio and the third ratio, and the outlet water pressure, the pollution degree of the RO assembly at the moment is obtained. The product of the second ratio and the third ratio and the outlet water pressure are positively correlated with the pollution degree, and the difference between the second ratio and the third ratio is negatively correlated with the pollution degree.

[0090] Wherein, the positive correlation means that the dependent variable will increase with the increase of the independent variable, and will decrease with the decrease of the independent variable. It can be an additive relationship, a multiplicative relationship, etc., which is determined by actual application. The negative correlation means that the dependent variable will decrease with the increase of the independent variable, and will increase with the decrease of the independent variable. It can be a subtraction relationship, a division relationship, etc., which is determined by actual application.

[0091] In this embodiment, a specific calculation formula for the pollution degree is given. The pollution degree at the i-th moment can be expressed as:

[0092] ;

[0093] in, represents the pollution level at the i-th moment, represents the ratio between the corrected conductivity of the sensor on the water inlet side of the RO component at the i-th moment and the conductivity of the sensor on the water inlet side of the RO component at the i-th moment, that is, the second ratio; represents the ratio between the corrected conductivity of the sensor on the outlet side of the RO component at the i-th moment and the conductivity of the sensor on the outlet side of the RO component at the i-th moment, that is, the third ratio; Indicates the outlet pressure of the RO component at the i-th moment, Represents the normalization function.

[0094] In this embodiment, 0.01 is added to the denominator of the calculation formula for the pollution degree in order to prevent the denominator from being 0. In specific applications, the implementer may set it according to specific circumstances. The smaller the value, the smaller the difference in conductivity between the inlet and product sides of the RO module. The larger the second ratio, the larger the third ratio, and the smaller the difference between the second and third ratios, the greater the degree of contamination at the i-th moment.

[0095] By adopting the above method, the pollution degree at each moment can be obtained.

[0096] The contamination level of RO components can interfere with the accuracy of salinity measurements. For example, contaminant accumulation in RO components can cause localized blockage of the water flow path, exacerbating concentration polarization and significantly increasing the salt concentration on the RO component surface compared to the main fluid. This can lead to falsely high readings on the conductivity sensor on the product water side. Furthermore, contaminants on RO components can cause non-steady-state changes in salt migration (e.g., sudden increases in conductivity), thus interfering with the accuracy of salinity measurements. Therefore, it is necessary to analyze the degree of interference with current salinity measurements based on the changing trend of RO component contamination.

[0097] During the desalination process, RO components are usually flushed to reduce the extent to which they are affected by pollutants and maintain the performance of the RO components.

[0098] If the current RO component has a high degree of pollution after the last RO component flushing, and the current degree of pollution has a large increase compared to the last RO component flushing, and the component has a low level in the current seawater desalination system (low-level component pollution is serious, which will cause the deterioration of the subsequent water quality), and the time from the last RO component flushing is short, then under the current state, the RO membrane filtration performance deteriorates quickly, and the performance of the RO component cannot be maintained by flushing, and the degree of interference with the salt measurement on both sides is greater.

[0099] Based on the above characteristics, the difference between the current degree of pollution and the degree of pollution after the last flushing at the current time is taken as the pollution growth amplitude. According to the degree of pollution after the last flushing at the current time, the pollution growth amplitude, the level of the component, and the time interval between the current time and the last flushing at the current time, the salt measurement interference index corresponding to the RO component is obtained. Specifically, the product between the degree of pollution after the last flushing at the current time and the pollution growth amplitude is calculated, and the product is denoted as a second product; the product between the level of the component and the time interval between the current time and the last flushing at the current time is denoted as a third product; the ratio of the second product to the third product is determined as the salt measurement interference index corresponding to the RO component. It should be noted that the degree of pollution after the last flushing is the degree of pollution at the first time after the completion of the last flushing.

[0100] So far, the salt measurement interference index corresponding to the RO component has been determined in this embodiment.

[0101] Step S4, adjusting the Kalman filter gain when denoising the salinity based on the salt measurement interference index, and obtaining the corrected salinity by filtering the salinity.

[0102] When the pollution growth trend of a certain RO component at the current time has a large interference degree on the salt measurement, the correction strength of the salinity measurement on both sides of the component should be increased to facilitate the reduction of the error accumulation of the salt measurement and the capture of the real salt fluctuation of the water quality.

[0103] Taking a single RO component as an example, the greater the interference degree of the current pollution growth trend of the component on the salt measurement on both sides of the component, the greater the correction strength of the salinity measurement on both sides of the component, and the smaller the corresponding Kalman filter gain.

[0104] Specifically, the difference between the constant 1 and the salt measurement interference index is calculated, and the difference is denoted as a second difference; the product between the second difference and the initial gain of the Kalman filter when denoising the salt measurement interference index is taken as the adjusted Kalman filter gain.

[0105] After determining the adjusted Kalman filter gain, the initially collected salinity is filtered using the Kalman filter algorithm, and the salinity obtained after filtering is recorded as the corrected conductivity. The Kalman filter algorithm is a prior art and will not be described in detail here.

[0106] At this point, the salinity of seawater has been measured using the method provided in this embodiment.

[0107] This embodiment monitors the conductivity and outlet pressure of each sensor on both sides of the RO component during the seawater desalination process. Based on the similarity in conductivity variation characteristics between each period in the historical cycle and the current period, and the difference in conductivity fluctuation between the historical period and the current period, a matching period for the current period is selected. The Kalman filter gain is adjusted based on the conductivity at all times in the current period and the difference in conductivity fluctuation between the current period and the period in which it matches the matching period. The conductivity collected by the sensor is then filtered. The contamination level of the RO component after flushing is evaluated based on the conductivity and corrected conductivity of the sensors on the inlet and outlet sides of the RO component, as well as the outlet pressure. The salinity measurement interference index corresponding to the RO component is determined based on the level of the RO component. The Kalman filter gain is then adjusted during salinity denoising, thereby achieving filtering of the salinity data and improving the accuracy of salinity measurement.

[0108] An embodiment of a water quality salinity measurement and correction system for seawater desalination:

[0109] See Figure 2 , which shows a structural block diagram of a water quality salinity measurement and correction system for seawater desalination provided by an embodiment of the present invention. The system may include a data acquisition module, a first correction module, a calculation module and a second correction module.

[0110] The data acquisition module is used to obtain the conductivity, outlet pressure, and salinity of each sensor on both sides of the RO component during the desalination process. The desalination process includes multiple historical cycles and a current cycle. Each cycle contains multiple time periods, and the current time period is the time period at the current moment.

[0111] A first correction module is configured to, for each sensor, select a matching period for the current period within each historical period based on the similarity between the conductivity change characteristics of each period within the historical period and the current period, and the conductivity fluctuation difference between the historical period and the current period; adjust the Kalman filter gain during conductivity denoising based on the conductivity at all times within the current period and the conductivity fluctuation difference between the current period and the period in which the matching period lies, and perform conductivity filtering to obtain a corrected conductivity;

[0112] The computing module is configured to obtain the pollution degree of the RO assembly at each moment according to the conductivities of the sensors on the water inlet side and the water outlet side of the RO assembly, the corrected conductivities, and the water outlet side pressure; and determine the salt measurement interference index corresponding to the RO assembly in combination with the pollution degree and the level of the RO assembly.

[0113] The second correction module is configured to adjust the Kalman filter gain when denoising the salinity based on the salt measurement interference index, and obtain the corrected salinity by filtering the salinity.

[0114] It should be understood that Figure 2 The structure diagram of the water quality salinity measurement correction system for seawater desalination and the modules thereof can be implemented in various ways. For example, in some embodiments, the system and the modules thereof can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented by using special logic; and the software part can be stored in a memory and executed by a suitable instruction execution system, such as a microprocessor or a specially designed hardware. Those skilled in the art can understand that the above-mentioned method and system can be implemented by using computer executable instructions and / or included in processor control code, such as the code provided on a carrier medium, such as a magnetic disk, CD or DVD-ROM, a programmable memory, such as a read-only memory (firmware), or a data carrier, such as an optical or electronic signal carrier. The system and the modules thereof in the present specification can not only be implemented by hardware circuit, such as a very large scale integrated circuit or a gate array, a semiconductor, such as a logic chip, a transistor, or a programmable hardware device, such as a field programmable gate array, a programmable logic device, etc., but also can be implemented by software, such as executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuit and software (for example, firmware).

[0115] More details about the above-mentioned modules can be referred to other places in the present specification, and will not be described here.

[0116] In other embodiments, a water quality salinity measurement correction device for seawater desalination is also provided, which includes a memory and a processor. The memory is configured to store executable program code, and the processor is configured to call and run the executable program code from the memory, so that the device executes the above-mentioned water quality salinity measurement correction method for seawater desalination. The device can be a chip, an assembly or a module, and the chip can include a connected processor and a memory; wherein the memory is configured to store instructions, and when the processor calls and executes the instructions, the chip can execute the above-mentioned water quality salinity measurement correction method for seawater desalination provided by the embodiments.

[0117] In other embodiments, a computer program product is also provided, which, when running on a computer, causes the computer to perform the above-mentioned related steps to realize the seawater desalination water quality salinity measurement correction method provided by the above-mentioned embodiments.

[0118] In other embodiments, a computer readable storage medium is also provided, which stores computer program code, when the computer program code runs on a computer, causes the computer to perform the above-mentioned related method steps to realize the seawater desalination water quality salinity measurement correction method provided by the above-mentioned embodiments.

[0119] Among them, the system, electronic equipment, computer program product, computer readable storage medium provided are used to execute the corresponding method provided above, so the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, which will not be described here.

[0120] It should be noted that: the above only describes the preferred embodiments of the present application, and does not limit the present application, any modification, equivalent replacement, improvement, etc. within the principles of the present application, should be included in the protection scope of the present application.

Claims

1. A method for measuring and correcting the salinity of water used in seawater desalination, characterized in that: The method comprises the following steps: Obtain the conductivity, outlet pressure, and salinity of each sensor on both sides of the RO component during the desalination process. The desalination process includes multiple historical cycles and a current cycle. Each cycle contains multiple time periods, and the current time period is the time period at the current moment. For each sensor, based on the similarity of conductivity change characteristics between each period in the historical cycle and the current period, and the conductivity fluctuation difference between the historical period and the current period, the matching period of the current period in each historical cycle is selected. The Kalman filter gain is adjusted during conductivity denoising based on the conductivity at all times in the current period and the conductivity fluctuation difference between the current period and the period in which the matching period belongs. The conductivity filter is then used to obtain the corrected conductivity. The contamination level of the RO component at each moment is determined based on the conductivity and corrected conductivity of the sensors at the inlet and outlet sides of the RO component, as well as the outlet pressure. The salt measurement interference index corresponding to the RO component is determined based on the contamination level and the level of the RO component. The Kalman filter gain is adjusted during salinity denoising based on the salt measurement interference index, and the salinity is filtered to obtain the corrected salinity.

2. The method for measuring and correcting salinity of water used in seawater desalination according to claim 1, characterized in that: The method of screening the matching period of the current period in each historical period based on the similarity of the conductivity change characteristics between each period in the historical period and the current period and the conductivity fluctuation difference between the historical period and the current period includes: For any period: The ratio between the range of the conductivity at all times in any period and the duration of any period is recorded as the conductivity characteristic value of any period; According to the difference between the conductivity characteristic value of the current period and each period in the historical period, the conductivity fluctuation similarity index of the current period and each period in the historical period is obtained; For any historical period: the period corresponding to the maximum value of the conductivity fluctuation similarity index in the historical period and the current period is used as the matching period of the current period in the historical period.

3. The method for measuring and correcting salinity of water used in seawater desalination according to claim 1, characterized in that: The Kalman filter gain for conductivity denoising is adjusted by combining the conductivity at all moments in the current period and the conductivity fluctuation difference between the current period and the period in which the current period matches the current period, including: For either sensor: Calculate the DTW distance between the conductivity curve of each historical period and the conductivity curve of the current period respectively, where the conductivity curve of each period is obtained by curve fitting the conductivity at all moments in the period; Calculate the first average value of the conductivity at all times within each matching period respectively; multiply the DTW distance between the conductivity curve of the period in which each matching period falls and the conductivity curve of the current period by the corresponding first average value, and record it as the first product corresponding to each matching period; and take the average value of the first products corresponding to all matching periods as the conductivity prediction mean value for the current period; Calculating the difference between the conductivity at each moment in the current time period and the predicted conductivity mean value as a first difference value corresponding to each moment in the current time period; calculating the average value of the first difference values ​​corresponding to all moments in the current time period; and taking the sum of the conductivity at each moment in the current time period and the average value of the first difference values ​​as the predicted value at each moment in the current time period; The difference between the conductivity at each moment in the current period and the corresponding predicted value is used as the difference index at each moment; Obtaining an error factor of the any one sensor at a current moment according to the DTW distance between the conductivity curves of the any one sensor and each of the remaining sensors in the current cycle and the difference index; The error factor is used to adjust the Kalman filter gain during conductivity denoising.

4. The method for measuring and correcting salinity of water used in seawater desalination according to claim 3, characterized in that: Obtaining the error factor of any one sensor at a current moment according to the DTW distance between the conductivity curves of any one sensor and each of the remaining sensors in the current cycle and the difference index includes: Calculating an average of the DTW distances between the conductivity curves of any one sensor and all other sensors in the current cycle; Calculate a first ratio between the difference index at the current moment and the average difference index of all moments in the current period; The product of the average value of the DTW distance and the first ratio is determined as the error factor of the any sensor in the current period.

5. The method for measuring and correcting salinity of water used in seawater desalination according to claim 3, characterized in that: The step of adjusting the Kalman filter gain during conductivity denoising by using the error factor includes: The difference between the constant 1 and the error factor is used as a first adjustment coefficient; The product of the first adjustment coefficient and the initial gain of the Kalman filter when denoising the conductivity is used as the adjusted Kalman filter gain.

6. The method for measuring and correcting salinity of water used in seawater desalination according to claim 1, characterized in that: The contamination degree of the RO component at each moment is obtained based on the conductivity and the corrected conductivity of the sensors at the water inlet and water outlet of the RO component, as well as the water outlet pressure, including: For any moment: Calculating a second ratio between the corrected conductivity of the sensor on the water inlet side of the RO component and the corresponding conductivity at any moment, and a third ratio between the corrected conductivity of the sensor on the water outlet side of the RO component and the corresponding conductivity; The contamination level of the RO component at any moment is obtained based on the product of the second ratio and the third ratio, the difference between the second ratio and the third ratio, and the outlet water pressure. The product of the second ratio and the third ratio and the outlet water pressure are both positively correlated with the contamination level, and the difference between the second ratio and the third ratio is negatively correlated with the contamination level.

7. The method for measuring and correcting salinity of water used in seawater desalination according to claim 1, characterized in that: Determining the salt measurement interference index corresponding to the RO component based on the pollution degree and the level of the RO component includes: The difference between the pollution level at the current moment and the pollution level after the previous flushing at the current moment is taken as the pollution level growth amplitude; The salt measurement interference index corresponding to the RO component is obtained according to the pollution degree after the previous flushing at the current moment, the pollution degree growth amplitude, the component level and the time interval between the current moment and the previous flushing at the current moment.

8. The method for measuring and correcting salinity of water used in seawater desalination according to claim 7, characterized in that: The salt measurement interference index corresponding to the RO component is obtained based on the pollution degree after the previous flushing at the current moment, the pollution degree growth amplitude, the component level, and the time interval between the current moment and the previous flushing at the current moment, including: Calculating a second product of the contamination level after the previous flush at the current moment and the magnitude of the contamination level increase, and a third product of the level of the RO component and the time interval between the current moment and the previous flush at the current moment; The ratio of the second product to the third product is determined as the salt measurement interference index corresponding to the RO component.

9. The method for measuring and correcting salinity of water used in seawater desalination according to claim 1, characterized in that: The method of adjusting the Kalman filter gain during salinity denoising based on the salt measurement interference index includes: calculating a second difference between the constant 1 and the salt determination interference index; The product of the second difference and the initial gain of the Kalman filter when denoising the salt measurement interference index is used as the adjusted Kalman filter gain.

10. A system for measuring and correcting salinity of water used in seawater desalination, the system being capable of implementing the method according to claim 1, characterized in that: The system comprises: The data acquisition module is used to obtain the conductivity, outlet pressure, and salinity of each sensor on both sides of the RO component during the desalination process. The desalination process includes multiple historical cycles and the current cycle. Each cycle contains multiple time periods, and the current time period is the time period at the current moment. A first correction module is configured to, for each sensor, select a matching period for the current period within each historical period based on the similarity between the conductivity change characteristics of each period within the historical period and the current period, and the conductivity fluctuation difference between the historical period and the current period; adjust the Kalman filter gain during conductivity denoising based on the conductivity at all times within the current period and the conductivity fluctuation difference between the current period and the period in which the matching period lies, and perform conductivity filtering to obtain a corrected conductivity; a calculation module for obtaining the contamination level of the RO component at each moment based on the conductivity and corrected conductivity of the sensors at the inlet and outlet sides of the RO component, as well as the outlet pressure; and determining the salt measurement interference index corresponding to the RO component based on the contamination level and the level of the RO component; The second correction module is used to adjust the Kalman filter gain during salinity denoising based on the salt measurement interference index, and to filter the salinity to obtain the corrected salinity.

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