Method for obtaining solid phase concentration in gas-solid two-phase flow under change of solid phase dielectric constant

Abstract

The application discloses a kind of solid-phase dielectric constant changes under capacitive gas-solid two-phase flow solid-phase concentration acquisition method, comprising: selecting multiple measurement capacitance sensor solid-phase concentration, offline establishing the representation relationship between multiple measurement capacitance sensor output value and calibration capacitance sensor output value;During the process of solid-phase concentration on-line measurement, when the on-line output value of calibration capacitance sensor indicates that the solid-phase dielectric constant changes, the on-line output value of calibration capacitance sensor and the multiple representation relationships established offline are used to obtain the data point set of measurement capacitance sensor about solid-phase concentration and corresponding output value, so as to obtain the fitting relationship between the output value of measurement capacitance sensor and solid-phase concentration under the measured solid-phase dielectric constant;The on-line output value of measurement capacitance sensor and the obtained fitting relationship are used to calculate the solid-phase concentration value under the change of solid-phase dielectric constant.The application can avoid the modeling difficulty problem caused by the non-linear relationship between capacitance sensor output value and the equivalent dielectric constant of measured domain.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of multiphase flow detection, and particularly to a solid phase concentration calculation algorithm in a capacitive gas-solid two-phase flow detection method under the condition of a change in the dielectric constant of the solid phase. BACKGROUND

[0002] Gas-solid two-phase flow widely exists in nature and industrial processes, such as chemical industry, power, metallurgy, food processing and other industrial sectors. In a gas-solid two-phase flow system, it is very important to measure the solid phase flow parameters, including the solid phase concentration, velocity and flow rate, etc. on-line for improving the efficiency and safety of industrial production. At present, various methods and technologies for measuring the solid phase flow parameters have been researched and developed. Among them, the concentration measurement method based on the capacitive sensor has attracted attention due to its advantages such as not being affected by the composition and amount of the carrier gas, simple structure, low cost, fast measurement speed and wide industrial application range. An important prerequisite for using the capacitive sensor to accurately measure the solid phase concentration in the gas-solid two-phase flow is that the dielectric constant of the solid phase medium is constant. Under the premise that the dielectric constant of the solid phase medium is known and constant, the relationship model between the output value of the capacitive sensor and the solid phase concentration is established through offline calibration experiments, so as to obtain the solid phase concentration by combining the on-line measurement of the capacitive value. However, in actual industrial processes, the dielectric constant of the solid phase medium may change due to uncontrollable factors such as raw material ratio and moisture content. For example, the change of coal type will cause the change of the dielectric constant of the coal powder. When the dielectric constant of the solid phase changes, the relationship model between the capacitive output value and the solid phase concentration used to calculate the solid phase concentration will also change. The concentration measurement model corresponding to the changed dielectric constant of the solid phase needs to be calibrated offline again. In a continuous running industrial process, offline calibration of the concentration measurement model for the changed dielectric constant of the solid phase is not practical. The use of the original concentration measurement model will cause the capacitive change caused by the change of the dielectric constant of the solid phase to be mistaken for the change of the solid phase concentration, resulting in obvious measurement error of the solid phase concentration. This is a common problem in the field of multiphase flow measurement using capacitive sensors to measure the solid phase concentration in gas-solid two-phase flow.

[0003] In view of the problem of the change of the dielectric constant of the solid phase in the process of capacitive solid phase concentration measurement, the existing solution proposes a concentration measurement method for compensating the dielectric constant of the solid phase on-line. Among them, the relationship between the capacitive output value of the first capacitive sensor (also referred to as the solid phase dielectric constant correction capacitive sensor) and the equivalent dielectric constant of the measured domain is used to determine the compensation value Δε s The relationship between the capacitive output value of the second capacitive sensor (also referred to as the solid phase concentration measurement capacitive sensor) and the equivalent dielectric constant of the measured domain is used to compensate the compensation value Δε sA solid-phase dielectric constant term is added to the output relationship of the second capacitance sensor to reduce or eliminate the influence of solid-phase dielectric constant changes on the sensor output, thereby obtaining the compensated solid-phase concentration. The compensation algorithm designed in this scheme needs to combine the relationship between the capacitance sensor output value and the equivalent dielectric constant of the measured domain to reduce the influence of solid-phase dielectric constant changes on the capacitance output value. However, due to the non-uniformity of the sensitive field inside the capacitance sensor and the complexity of the equivalent dielectric constant model, the relationship between the sensor capacitance output value and the equivalent dielectric constant of the measured domain is non-linear when both solid-phase concentration and solid-phase dielectric constant change simultaneously. Therefore, accurately establishing the relationship model between the sensor capacitance output value and the equivalent dielectric constant requires further in-depth research and analysis, which affects the usability of the online solid-phase dielectric constant compensation method and the real-time performance of online measurement. For the gas-solid two-phase flow solid-phase concentration measurement method based on corrected solid-phase dielectric constant, how to achieve efficient and accurate online calculation of solid-phase concentration under changes in solid-phase dielectric constant is a key problem that needs to be solved. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention discloses a method for obtaining the solid phase concentration in a capacitive gas-solid two-phase flow under varying solid phase dielectric constants. The specific steps are as follows: Select n capacitive sensors to measure the solid phase concentration. Under the selected k-th (k = 1, 2, ..., n) solid phase concentration, select m solid media with different dielectric constants to obtain the output value C of the capacitive sensors. 2_k_l With the output value C of the calibration capacitance sensor 1_l Combined data point set {(C 1_l C 2_k_l The function is to use the formula |k=1,2,...,n,l=1,2,...,m} to perform offline fitting and measurement of the output value C of the capacitive sensor. 2_k Characterization relationship between the measurement capacitance sensor output value C1 and the calibration capacitance sensor output value C1; establish n offline measurement capacitance sensor output values ​​C1 at n different selected solid phase concentrations. 2_k The characterization relationship between the calibration capacitor sensor output value C1 and the solid phase concentration is established. During the online measurement of solid phase concentration, when the online output value of the calibration capacitor sensor indicates the change in the solid phase dielectric constant, the data point set of the measuring capacitor sensor with respect to the solid phase concentration and the corresponding output value under the current measured solid phase dielectric constant is obtained online using the online output value of the calibration capacitor sensor and the n characterization relationships established offline. This allows for fitting the relationship between the measuring capacitor sensor output value and the solid phase concentration under the current measured solid phase dielectric constant. Using the online output value of the measuring capacitor sensor and the fitting relationship between the online measuring capacitor sensor output value and the solid phase concentration, the solid phase concentration value within the measuring capacitor sensor under the change in solid phase dielectric constant is calculated.

[0005] The output values ​​C of the capacitance sensor at different solid concentrations were established through offline calibration experiments. 2_k The relationship between (k = 1, 2, ..., n) and the output value C1 of the calibration capacitance sensor can be expressed as:

[0006]

[0007] In the formula, β s1 The solid phase concentration of the calibration capacitive sensor with a fixed concentration is denoted as β. s1_1 ;β s2 Represents the solid phase concentration of the measured capacitance sensor, β s2_1 ,β s2_2 ,…β s2_n C1 represents the n solid phase concentration values ​​(1, 2, ..., n) selected for the measurement capacitance sensor in the offline calibration experiment, which are used as solid phase concentration data points to establish the fitting relationship between the measurement capacitance sensor output value and the solid phase concentration; C1 is β s1 =β s1_1 At that time, different solid phase permittivity ε s The output values ​​of the lower calibration capacitance sensor indicate the dielectric constant of the measured solid medium; C 2_k (k = 1, 2, ..., n) is β s2 =β s2_k At that time, the dielectric constant ε of different solid media s The following measures the output values ​​of the capacitive sensor. Characterization relationship ff k (.)(k=1,2..,n) is β s1 =β s1_1 ,β s2 =β s2_k (k = 1, 2, ..., n), dielectric constant ε of the solid medium s At different times, establish the measurement of the capacitance sensor output value C. 2_k The characterization relationship between the output value C1 of the calibration capacitor sensor and the calibration capacitor sensor.

[0008] A sufficient number of data points are selected relatively evenly within the working range, and the characterization relationship between the measurement signal and the measured parameter is defined by fitting a curve. Specifically, the number of solid phase concentrations (n) selected for the online fitting of the relationship between the measurement capacitance sensor output value and the solid phase concentration, and the number of solid phase concentrations (n) used for fitting the curve between β... s1 =β s1_1 ,β s2 =β s2_k When (k=1,2..,n), fit the measured output value C of the capacitive sensor. 2_k The number of dielectric constants m selected for the solid medium in relation to the output value C1 of the calibration capacitor sensor is usually not less than 5.

[0009] n selected solid phase concentration values {β s2_1 ,β s2_2 ,…β s2_n} of the measuring capacitance sensor are used to fit the relationship curve between the output value of the measuring capacitance sensor and the solid phase concentration, which should cover the solid phase concentration values required to be measured by the measuring capacitance sensor during online measurement; similarly, m selected dielectric constant values {ε s_1 ,ε s_2 ,…,ε s_m} of the solid phase medium are used to fit the relationship curve between the output value of the measuring capacitance sensor C 2_k (k = 1, 2.., n) and the output value of the calibration capacitance sensor C1, which should cover the dielectric constant values of the solid phase medium required to be measured by the measuring capacitance sensor during online measurement.

[0010] The data point set used to fit each of the characteristic relationship ff k (.)(k = 1, 2.., n) offline at the selected kth solid phase concentration of the measuring capacitance sensor includes: β s1 = β s1_1 ,β s2 = β s2_k (k = 1, 2.., n), m selected dielectric constant values ε s_1 ,ε s_2 ,…,ε s_m of the solid phase medium are selected to obtain the corresponding values {C 2_k , C 2_k_1 ,…, C 2_k_2} of the output value of the measuring capacitance sensor C 2_k_m and the corresponding values {C 1_1 , C 1_2 ,…, C 1_m} of the output value of the calibration capacitance sensor C1. Wherein, the dielectric constant of the solid phase medium in the calibration capacitance sensor is consistent with the dielectric constant of the solid phase medium in the measuring capacitance sensor, that is, the data point set used to fit the characteristic relationship ff k (.)(k = 1, 2.., n) is {(C 1_1 , C 2_k_1 ), (C 1_2 , C 2_k_2 ),…,(C 1_m , C 2_k_m )}(k = 1, 2.., n).

[0011] The online output value of the calibration capacitance sensor indicates the dielectric constant information of the currently measured solid phase medium, and only needs to judge whether the dielectric constant of the measured solid phase medium changes according to the online output value of the calibration capacitance sensor, without the need to calculate the dielectric constant value of the solid phase medium.

[0012] When the dielectric constant of the measured solid-phase medium changes, the current dielectric constant ε s * (ε s_1 <=ε s * <=ε s_m ) of the correction capacitor sensor online output value C1 * is substituted into the n offline established characteristic relationships, the data point set of the measurement capacitor sensor under the current measured solid-phase medium dielectric constant can be obtained online. The data point set includes the selected n solid-phase concentrations {β s2_1 ,β s2_2 ,…,β s2_n} of the measurement capacitor sensor and the corresponding output values {ff1(C1 * ),ff2(C1 * ),…,ff n (C1 * )} of the measurement capacitor sensor under each solid-phase concentration.

[0013] Based on the obtained data point set {(β s2_1 ,ff1(C1 * )),(β s2_2 ,ff2(C1 * )),…,(β s2_n ,ff n (C1 * )} of the solid-phase concentration and the corresponding output value of the measurement capacitor sensor under the current measured solid-phase medium dielectric constant, the relationship between the output value C2 of the measurement capacitor sensor and the solid-phase concentration β s2 is fitted online, which is used to calculate the measured solid-phase concentration value β s2 * (β s2_1 <=β s2 * <=β s2_n ).

[0014] By employing the above technical solution, this invention provides a method for obtaining solid phase concentration in capacitive gas-solid two-phase flow under varying solid phase dielectric constant. This algorithm can update the relationship between the output value of the measuring capacitive sensor and the solid phase concentration online under varying solid phase dielectric constant, avoiding the modeling difficulties caused by the nonlinearity of the relationship between the output value and the equivalent dielectric constant. During use, when the solid phase dielectric constant information changes, there is no need to perform multiple related offline calibration experiments. Simultaneously, this algorithm directly establishes multiple fitting relationships between the output values ​​of the calibration and measurement capacitive sensors, eliminating the need for solid phase dielectric constant information parameters, simplifying the offline calibration process, and improving online efficiency. This algorithm effectively solves the measurement problem of large solid phase concentration measurement errors caused by variations in the solid phase dielectric constant during continuous production processes. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the overall method for obtaining solid phase concentration in capacitive gas-solid two-phase flow under varying solid phase dielectric constant in this invention.

[0017] Figure 2 These are multiple characterization relationships established offline in this invention between the output values ​​of the measured capacitance sensor and the output values ​​of the calibrated capacitance sensor.

[0018] Figure 3 This represents the fitting relationship between the output value of the measurement capacitance sensor and the solid phase concentration, updated during the actual measurement process in this invention.

[0019] Figure 4 This is a comparison chart of the relative errors of solid concentration obtained by different calculation methods in the actual measurement process of this invention. Detailed Implementation

[0020] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention:

[0021] like Figure 1 The method for obtaining solid concentration in capacitive gas-solid two-phase flow under varying solid-phase dielectric constant, as shown, specifically includes the following steps:

[0022] When the gas-solid two-phase flow passes through the capacitance sensor in the pipeline, the capacitance between the electrodes changes with the effective dielectric constant in the measured domain. The effective dielectric constant in the measured domain is closely related to the solid phase concentration and the dielectric constant of the solid phase medium. The measured solid phase concentration is related to the gas phase concentration and the dielectric constant of the gas phase, and the dielectric constant of the gas phase is stable and can be regarded as a constant value. The mathematical model between the output value C2 of the measurement capacitance sensor and the effective dielectric constant of the measured domain is represented as:

[0023] C2=F2(f(β s2 ,ε s ))0<β s2 ≤1 (1)

[0024] In the formula, β s2 is the solid phase concentration of the measurement capacitance sensor, ε s is the dielectric constant information of the solid phase. F2(.) represents the relationship between the output value C2 of the measurement capacitance sensor and the effective dielectric constant, and f(.) represents the relationship between the equivalent dielectric constant and the dielectric constant information ε s of the solid phase and the solid phase concentration β s2 . In the actual measurement process, the dielectric constant of the solid phase will change due to water, material ratio and other reasons, thereby affecting the output value of the capacitance. In this case, if the dielectric constant of the solid phase is not corrected, the measurement system will mistakenly consider the change of the output value caused by the dielectric constant of the solid phase as the change of the solid phase concentration, thereby producing obvious measurement error of the solid phase concentration.

[0025] A correction capacitance sensor is introduced to provide the measured dielectric constant information of the solid phase online. The relationship between the output value C1 of the correction capacitance sensor and the equivalent dielectric constant of the measured domain can be represented as:

[0026] C1=F1(f(β s1 ,ε s ))0<β s1 ≤1 (2)

[0027] In the formula, β s1 is the solid phase concentration of the correction capacitance sensor, and ε s is the dielectric constant information of the solid phase. The solid phase medium with the same dielectric constant in the correction capacitance sensor and the measurement capacitance sensor is the same or different in structure. F1(.) represents the relationship between the output value C1 of the correction capacitance sensor and the effective dielectric constant. According to formula (2), the updated dielectric constant information of the solid phase is:

[0028] ε s =f εs -1 (F1 -1 (C1),β s1 ) (3)

[0029] where f εs -1 (.) represents the inverse relation of f(.) s with ε -1 as the argument. F1 s (.) represents the inverse relation of F1(.) εs When the solid phase concentration is known and fixed, the updated solid phase dielectric constant information can be obtained from (3). Considering the solid phase concentration as a constant value, (3) can be simplified as:

[0030] ε -1 = f -1 s1_1 (F1 -1 (C1), β s1 ) = ff s1_1 (C1) (4)

[0031] where ff(.) is the inverse relation of ff(.) s with β -1 as the argument. Based on the obtained solid phase dielectric constant information, the measured solid phase concentration in the capacitive sensor can be obtained from (1):

[0032]

[0033] where F2 -1 (.) represents the inverse relation of F2(.) βs -1 (.) represents the inverse relation of f(.) s with β eff as the argument. Using the equivalent dielectric constant model ε s = f(ε s , β s ) = β s ε s + (1 - β g ) ε s1 , (5) can be characterized as:

[0034]

[0035] From (6), ff(.) is the inverse relation of ff(.) s1_1 with β s as the argument.F2(.) is the relationship between the measured capacitance output value C2 and the equivalent dielectric constant of the measured domain, which is calculated from the different solid phase concentration and the different solid phase dielectric constant information. Due to the non-uniformity of the sensitive field and the complexity of the equivalent dielectric constant mixture model, F2(.) has significant nonlinearity, i.e. it cannot be accurately characterized by a single linear model. However, when the solid phase dielectric constant information is determined, the relationship between the output value of the measured capacitance sensor and the equivalent dielectric constant is easy to establish and characterize.

[0036] In the obtained updated solid phase dielectric constant information ε s = ff -1 (C1), based on ε eff = β s ε s + (1- β s ) ε g = β s ( ε s - ε g ) + ε g , the equivalent dielectric constant of the measured capacitance sensor can be characterized as FF -1 (C2) (ff -1 (C1) - ε g ) + ε g . Where FF(.) represents the relationship between the output value C2 of the measured capacitance sensor and the solid phase concentration β s2 under the currently measured solid phase medium dielectric constant. Then, as shown in (7), in order to obtain the concentration measurement value of the solid phase dielectric constant after correction, it is only necessary to obtain the relationship between the output value C2 of the measured capacitance sensor and the solid phase concentration β s2 under the currently measured solid phase medium dielectric constant.

[0037]

[0038] In order to be able to update the relationship FF(.) between the output value of the measured capacitance sensor and the solid phase concentration in real time according to the change of the solid phase dielectric constant, it is necessary to obtain a series of output values of the measured capacitance sensor corresponding to different solid phase concentrations under the change of the solid phase dielectric constant. At a fixed solid phase concentration, the relationship between the capacitance output value and the solid phase dielectric constant information can be established. Based on this relationship, when the solid phase dielectric constant information is determined, an output value with this solid phase concentration can be obtained. Similarly, a plurality of characterization relationships between the output value of the measured capacitance sensor and the solid phase dielectric constant information can be established at different solid phase concentrations, as shown in (8).

[0039]

[0040] Where ffk (k = 1, 2,.., n) represents β s2 = β s2_k The capacitance C of the measurement capacitance sensor is measured 2_k and the solid phase dielectric constant information ε s The relationship between β s2_1 , β s2_2 ,... β s2_n respectively selected n solid phase concentration values of the measurement capacitance sensor; at the same time, the correction capacitance sensor working at β s1 = β s1_1 The solid phase dielectric constant information obtained by the correction capacitance sensor is represented as ε s = ff -1 (C1). Then, (8) can be represented as (9).

[0041]

[0042] In the formula, C1 is β s1 = β s1_1 , the output value of the correction capacitance sensor under different solid phase dielectric constants ε s ; C 2_k (k = 1, 2,.., n) is the output value of the measurement capacitance sensor under different solid phase dielectric constants ε s2 = β s2_k , the output value of the measurement capacitance sensor under different solid phase dielectric constants ε s . The relationship ff k (.)(k = 1, 2,.., n) is β s1 = β s1_1 , β s2 = β s2_k (k = 1, 2,.., n), the solid phase dielectric constant ε s is different, the relationship between the output value C 2_k of the measurement capacitance sensor and the output value C1 of the correction capacitance sensor is established.

[0043] As shown in (9), the online output value of the correction capacitance sensor indicating the change of the solid phase dielectric constant is used to realize the online update of the relationship between the output value of the measurement capacitance sensor and the solid phase concentration through multiple characteristic relationships established offline. The coefficients of the above relationship need to be fitted according to the specific application by offline calibration experiments. Specifically as follows:

[0044] (1) In the offline calibration experiment, different solid phase dielectric constant values and different measurement capacitance sensor solid phase concentration values in the working range are selected as uniformly as possible, and the number of selected values is usually not less than 5. Assuming that the solid phase dielectric constant information ε s The number of data points and the number of measurement capacitance sensor solid phase concentration β s2 The number of data points are m (εs _1,ε s _2,…,ε s _ m ) and n (β s2_1 ,β s2_2 ,…β s2_n ).

[0045] (2) For the calibration capacitor sensor, at a known and fixed solid phase concentration, m data points {(ε s_1 ,C 1_1 ),(ε s_2 ,C 1_2 ),…(ε s _ m ,C 1_m )} are obtained from m solid phase dielectric constant information.

[0046] (3) For the measurement capacitor sensor, data point sets are obtained at n different solid phase concentrations (β s2_1 ,β s2_2 ,…β s2_n ). Among them, for the k (k = 1, 2.., n) concentration β s2_k , m data points {(ε s_1 ,C 2_k_1 ),(ε s_2 ,C 2_k_2 ),…(ε s_m ,C 2_k_m )} (k = 1, 2.., n) are obtained from m solid phase dielectric constant information.

[0047] (4) Based on {(ε s_1 ,C 1_1 ),(ε s_2 ,C 1_2 ),…(ε s_m ,C 1_m )} obtained by the calibration capacitor sensor and {(ε s_1 ,C 2_k_1 ),(ε s_2 ,C 2_k_2 ),…(ε s_m ,C 2_k_m )} obtained by the measurement capacitor sensor at the solid phase concentration β s2_k (k = 1, 2.., n), data point sets {(C 1_1 ,C 2_k_1 ),(C 1_2 ,C 2_k_2 ),…,(C 1_m ,C 2_k_m )} are obtained; using the obtained data point sets, the output value C 2_kAnd the calibration of the capacitance sensor output value C1 in measuring the solid phase concentration β of the capacitance sensor s2_k The fitting relationship is then established. Similarly, for the selected n different solid phase concentrations of the capacitance sensor, a total of n offline measurement capacitance sensor output values ​​C are established. 2_k The characterization relationship between the calibration capacitor sensor output value C1 and the calibration capacitor sensor output value C1 is now complete; the offline calibration experiment is thus finished.

[0048] When the measured solid phase dielectric constant changes, it will reflect the current measured solid phase dielectric constant ε. s * The online output value C1 of the calibration capacitance sensor * Substituting these into the n characterization relationships established offline, we can obtain online the data point set of the capacitance sensor under the measured dielectric constant of the solid medium, i.e., {(β s2_1 ,ff1(C 1_* )),(β s2_2 ,ff2(C1 * )),…,(β s2_n ,ff n (C1 * Then, the online fitting measurement of the capacitive sensor output value C2 and the solid phase concentration β is performed. s2 The relationship is used to calculate the solid concentration value measured by the capacitive sensor under the change of solid phase dielectric constant.

[0049] Experimental verification and results:

[0050] 1. Offline calibration experiment

[0051] (1) It is assumed that the commonly used relative permittivity of solid phase is 5. However, in actual measurement, the relative permittivity of the solid medium is affected by factors such as the mixing ratio and moisture content, and fluctuates within the range of 3-8. The selected data point set for different relative permittivity of solid phase is {3, 4, 5, 6, 7, 8}. Based on specific applications, the selected data point set for different solid phase concentrations is {0.09, 0.16, 0.36, 0.49, 0.64, 0.81}.

[0052] (2) An asymmetric concave-wall capacitive sensor was selected as the calibration capacitive sensor. Considering better sensor output linearity and usability, the solid phase concentration of the calibration sensor was typically designed to be 1. With a solid phase concentration of 1, the output values ​​of the calibration capacitive sensor were obtained for solid phase relative permittivity of 3, 4, 5, 6, 7, and 8. A double-helix capacitive sensor was selected as the measurement capacitive sensor, and the output values ​​of the measurement capacitive sensor were obtained for solid phase concentrations of 0.09, 0.16, 0.36, 0.49, 0.64, and 0.81. For each solid phase concentration, the output values ​​for solid phase relative permittivity of 3, 4, 5, 6, 7, and 8 were obtained.

[0053] (3) Based on the obtained data point set, 6 fitting curves between the output values of the calibration capacitive sensor and the output values of the measurement capacitive sensor are established at the selected 6 solid phase concentrations. Taking the solid phase concentration value 0.09 as an example: based on the obtained data point set of the calibration capacitive sensor at the solid phase concentration 1 and different solid phase relative dielectric constants and the obtained data point set of the measurement capacitive sensor at the solid phase concentration 0.09 and different solid phase relative dielectric constants, a fitting relationship between the output values of the measurement capacitive sensor and the output values of the calibration capacitive sensor can be established on the premise that the solid phase medium dielectric constants in the calibration capacitive sensor are consistent with the solid phase medium dielectric constants in the measurement capacitive sensor. Similarly, the fitting relationship can be established at other solid phase concentration points, and the results are shown in Figure 2 .

[0054] 2. Online measurement

[0055] (1) The online output value of the calibration capacitive sensor is judged, and when the online output value changes compared with the output value obtained when the solid phase relative dielectric constant is 5, it indicates that the currently measured solid phase dielectric constant changes.

[0056] (2) According to the obtained online output value of the calibration capacitive sensor, the output values of the measurement capacitive sensor corresponding to 6 different solid phase concentrations can be obtained by using the 6 different solid phase concentration representation relationships established by the offline calibration experiment. Based on the solid phase concentration value and the corresponding output value, the relationship between the output value of the measurement capacitive sensor and the solid phase concentration at the currently measured solid phase dielectric constant is updated online. As shown in Figure 3 , the fitting relationship between the online updated output value of the measurement capacitive sensor and the solid phase concentration when the currently measured solid phase relative dielectric constant is 4, 4.5, 5.5, and 6, respectively, is shown.

[0057] (3) The solid phase concentration measurement value under the change of the solid phase dielectric constant is calculated by using the online output value of the measurement capacitive sensor and the fitting relationship between the output value of the measurement capacitive sensor and the solid phase concentration. Figure 4 The relative errors of the measured solid phase concentrations under the change of the solid phase dielectric constant without considering and the relative errors of the measured solid phase concentrations under the change of the solid phase dielectric constant by using the present application are shown. The concentration measurement cases are 0.1225, 0.5625, and 0.81, respectively. The relative error of the measured solid phase concentration is defined as:

[0058]

[0059] In the formula, β ms is the measured solid phase concentration value, and β ts is the true solid phase concentration value. It can be seen that the present application effectively realizes the efficient and accurate calculation of the solid phase concentration under the change of the solid phase dielectric constant.

[0060] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent substitutions or changes according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A method for obtaining the concentration of solid phase in gas-solid two-phase flow by measuring the change of capacitance with the dielectric constant of solid phase, characterized in that The following steps are: In the solid phase concentration combination measurement under the solid phase dielectric constant change, it includes: the correction capacitor sensor with fixed solid phase concentration and the measurement capacitor sensor with dynamic solid phase concentration; selecting n one measurement capacitor sensor solid phase concentration, selecting k ( k=1,2..,n ) one measurement capacitor sensor solid phase concentration, selecting m one solid phase medium with different dielectric constant, obtaining the data point set of the measurement capacitor sensor output value C 2_k_l and the correction capacitor sensor output value C 1_l combination C 1_l , C 2_k_l )| k= 1,2，...,n , l=1,2，...,m}, thereby fitting the characteristic relationship between the measurement capacitor sensor output value C 2_k and the correction capacitor sensor output value C 1 offline; offline establishing n the characteristic relationship between the measurement capacitor sensor output value n 2_k and the correction capacitor sensor output value C 1 under the selected different measurement capacitor sensor solid phase concentration. In the process of online measurement of solid phase concentration, the online output value of the correction capacitor sensor indicates the dielectric constant information of the current measured solid phase medium, reflecting whether the dielectric constant of the measured solid phase medium changes; characterizing the relationship between the online output values of the capacitance sensor and the offline established n table, obtaining an online data point set of the capacitance sensor at a current measured dielectric constant of the solid phase medium, wherein the data point set comprises a selected n number of solid phase concentration values at the current measured dielectric constant of the solid phase medium and a corresponding n number of output values of the capacitance sensor measured at each solid phase concentration; Based on the obtained data point set of the measurement capacitor sensor, the fitting relationship between the output value of the measurement capacitor sensor and the solid phase concentration under the dielectric constant of the current measured solid phase medium is obtained online; Based on the obtained fitting relationship between the output value of the measurement capacitor sensor and the solid phase concentration, the solid phase concentration value measured by the measurement capacitor sensor under the change of the dielectric constant of the solid phase is calculated by using the online output value of the measurement capacitor sensor.

2. The method according to claim 1, wherein the method is characterized by: a characteristic relationship between the output value of the measurement capacitance sensor and the output value of the correction capacitance sensor is represented by: n C 2_k k=1,2..,n C 1​​​ In the formula, represent the solid phase concentration of the calibration capacitor sensor with a fixed concentration, set as β s1_1 ; represent the solid phase concentration of the measurement capacitor sensor, β s2_1 , β s2_2 ,…β s2_n respectively, the solid phase concentration 1, the solid phase concentration 2, …, the solid phase concentration n total n solid phase concentration values, as the solid phase concentration data points when establishing the fitting relationship between the output values of the measurement capacitor sensor and the solid phase concentration; C 1 is = β s1_1 different solid phase dielectric constants ɛ s The output values of the calibration capacitor sensor below can indicate the dielectric constant information of the measured solid phase medium; C 2_k ( k=1,2..,n ) is = β s2_k different solid phase medium dielectric constants ɛ s The output values of the measurement capacitor sensor below represent the relationship ff k (.) ( k=1, 2..,n ) is = β s1_1 , = β s2_k ( k=1,2..,n ), the solid phase medium dielectric constant ɛ s is different, the output values of the measurement capacitor sensor C 2_k and the output values of the calibration capacitor sensor C 1 are established.

3. The method according to claim 2, wherein the method is characterized by: Within the working range, a sufficient number of data points are selected, and the characterization relationship between the measurement signal and the measured parameter is defined by fitting a curve. Specifically, the number of solid phase concentrations of the measurement capacitance sensor selected for online fitting of the relationship curve between the measurement capacitance sensor output value and the solid phase concentration is [not specified in the original text]. n and used in = β s1_1 , = β s2_k ( k=1, 2..,n When fitting the output value of the capacitive sensor, the measurement is performed. C 2_k With the output value of the calibration capacitance sensor C The number of solid dielectric constants selected for the relationship curve between 1 and 1 m Each must have at least 5.

4. The method according to claim 3, wherein the method is characterized by: selected for fitting the curve relating the output value of the measuring capacitance sensor and the concentration of the solid phase n β s2_1 , β s2_2 ,…β s2_n , which should cover the range of values of the concentration of the solid phase to be measured by the measuring capacitance sensor during its on-line measurements; similarly, the curve relating the output value of the measuring capacitance sensor C 2_k k=1,2..,n C 1, selected for fitting the curve relating the output value of the measuring capacitance sensor and the dielectric constant of the solid phase medium m ɛ s_1 ,ɛ s_2 ，…， ɛ s_m , which should cover the range of values of the dielectric constant of the solid phase medium to be measured by the measuring capacitance sensor during its on-line measurements.​​​​ 5. The method of claim 2, wherein the method is a method of obtaining the concentration of the solid phase in a gas-solid two-phase flow with a change in the dielectric constant of the solid phase. In the selected number k Under the condition of solid phase concentration measured by a single capacitive sensor, each characterization relationship is fitted offline. ff k (.) ( k=1,2..,n The data point set used at that time includes: = β s1_1 , = β s2_k ( k=1,2..,n When selecting m The dielectric constant of a solid dielectric ɛ s_1 ,ɛ s_2 , …,ɛ s_m Obtain the output value of the capacitance sensor. C 2_k Corresponding value { C 2_k_1 ， C 2_k_2 ，…，C 2_k_m } and the output value of the calibration capacitance sensor C The value corresponding to 1 { C 1_1 ，C 1_2 ，…，C 1_m In this context, the dielectric constant of the solid-phase medium within the calibration capacitor sensor is consistent with the dielectric constant of the solid-phase medium within the measurement capacitor sensor, i.e., it is used to fit the characterization relationship. ff k (.) ( k=1,2..,n The data point set used when ) is {( C 1_1 , C 2_k_1 ) , ( C 1_2 , C 2_k_2 ) , …, ( C 1_m , C 2_k_m )}( k=1,2..,n ).

6. The method of claim 1, wherein: The online output value of the correction capacitor sensor indicates the dielectric constant information of the current measured solid phase medium, and only needs to judge whether the dielectric constant of the measured solid phase medium changes according to the online output value of the correction capacitor sensor, without the need to calculate the dielectric constant value of the solid phase medium.

7. The method of claim 1, wherein the method is a method of obtaining the concentration of the solid phase in a gas-solid two-phase flow with a change in the dielectric constant of the solid phase. When the dielectric constant of the measured solid-phase medium changes, the current dielectric constant of the measured solid-phase medium will be reflected ɛ s ( ɛ s_1 <= ɛ s <= ɛ s_m ) of the correction capacitance sensor online output value C1 Substitute the offline established n characteristic relationship, the data point set of the measurement capacitance sensor under the current dielectric constant of the measured solid-phase medium can be obtained online, wherein the data point set contains the selected n solid-phase concentration β s2_1 , β s2_2 ,…, β s2_n and the corresponding output value of the measurement capacitance sensor under each solid-phase concentration ff 1(C1 ) , ff 2(C1 ) , …, ff n (C1 ) 8. The method according to claim 7, wherein the method is characterized by: based on the obtained data set of solid phase concentration versus corresponding output value at the current measurement solid phase medium dielectric constant β s2_1 , ff 1(C1 )) , (β s2_2 , ff 2(C1 )) , …, ( β s2_n , ff n (C1 )) for the measurement solid phase medium dielectric constant C 2 to calculate the measured solid phase concentration value ( β s2_1 <= <= β s2_n ).​

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