RU2423674C2 - Method of measuring parameters of flowing multicomponent media - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: method of measuring parameters of flowing multicomponent media, passing through at least one pipe, such as media flow rate, pressure, temperature and moisture content using sensors installed in openings in the pipe and involving transmitting and processing measuring results, involves continuous measurement, and parameter values obtained from each sensor are continuously are continuously processed in a measurement information processing unit according to an algorithm for processing measurement information taking into account the effect of measured parameters on each other, design features of the sensors and dynamic properties of the measuring transducers.

EFFECT: high dynamic accuracy of measurements and high speed of operation in transient flow modes in a pipe.

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Description

The invention relates to measuring equipment and can be used to measure the parameters of multicomponent media in pipelines in the oil, gas, chemical, food and other industries.

A known method of controlling the characteristics of the gas stream [RF Patent No. 2159847], in which measurement bases are created by forming counting volumes and record the moments of flight of the boundaries of the measurement base with the optical receiving device (OPP), is converted to a sequence of voltage pulses using a processing unit signals and transmit it through the blocker to the controller, where according to a given algorithm, the parameters of the pulses are measured, the characteristics of the gas flow are calculated from them, and the control signal to the actuator.

The disadvantages of this method is the lack of a continuous calculation of the parameters of the gas stream and the low accuracy of the measurements of the parameters of the gas stream, due to the need to adjust the transverse dimensions of the counted volumes.

The method of monitoring the technical condition and regulation of the operation of the gas transportation complex [RF Patent No. 2170876], in which, when measuring gas flow parameters, measurement information is transmitted and parameters such as pressure, temperature and flow are processed at the central control center, and the data obtained are compared with rated values calculated for a given mode.

The disadvantage of this method is the low accuracy of the measurements, due to the frequency of measurement of gas flow parameters, and the lack of consideration of parameter values in transient modes of transmission and processing of measurement information, as well as the need to calculate the nominal parameter values for a given mode.

Of the known methods for measuring the parameters of multicomponent media, the closest to the claimed one is a method for measuring the parameters of flowing multicomponent media passing through at least one pipeline [RF Patent No. 2315960], in which the measurements are carried out by means of a temperature sensor and a measuring unit installed in the pipeline rupture. Measurements take place continuously and cyclically at different frequencies of alternating voltage. The measurement information is fed to the corresponding processing unit, and then the measurements are compared in the computer with a data bank, the analysis of which calculates such environmental parameters as the flow rate, temperature.

The main disadvantage of this method is the lack of measurement performance in cyclic measurements at different frequencies of an alternating voltage of the same local volume and low accuracy in calculating parameter values as a result of comparing measurements in a computer with a data bank.

The technical result achieved by the invention is to increase the dynamic accuracy of the measured parameters and the speed of obtaining reliable information about the flow parameters in transient modes of flow in the pipeline.

The technical result is achieved by measuring the parameters of the multicomponent flow, processing and transmitting the measurement results, as the measured parameters of the multicomponent flow, the flow rate of the medium, pressure, humidity and temperature in the pipeline are used, while new is that the measurements are carried out continuously, and the obtained values the parameter from each sensor is continuously processed in the measuring information processing unit according to the measurement information processing algorithm, taking into account the mutual influence and measure parameters on each other, the design features of the sensors and the dynamic properties of the transducers.

The structural features of the platinum resistance thermal converter include a multilayer cylindrical structure, which consists of steel, aluminum and platinum layers.

The design features of the differential pressure sensor include the presence of a membrane to separate the two chambers of the sensor. When filling one chamber with gas, another is emptied, which causes the membrane to bend, and forms an electrical signal.

The invention is illustrated by drawings, where:

- figure 1 presents a structural diagram illustrating a method for measuring the parameters of flow multicomponent media, and containing:

1 - pipeline with a moving multiphase flow;

2 - temperature sensor;

3, 4 - pressure sensors installed respectively at the inlet and outlet of the measuring line;

5 - humidity sensor, for example optical;

6 - processing information processing unit;

7, 8, 9, 10 - values of multiphase flow parameters.

11 - an oscilloscope.

- figure 2 presents a diagram of the mutual influence of the parameters on each other;

- figure 3 presents a simulation model of the measuring system, timing diagrams for determining the values of the flow parameters;

- figure 4 presents the algorithm for processing measurement information;

- figure 5 presents a simulation model of the measuring system and timing diagrams for determining the actual values of the flow parameters.

The main task when measuring the parameters of a multicomponent flow in transient conditions of technological processes is to obtain reliable information in a minimum time. A feature of measuring the parameters of multicomponent flows is to take into account the mutual influence of the parameters on each other and to identify the actual values of such parameters as temperature, pressure, humidity and mass flow in both static and dynamic modes.

A multicomponent medium during movement is characterized by a constant mass flow rate. The change in mass flow occurs due to the pressure drop at the inlet and outlet of the measuring line of the pipeline 1 and is described by the equation based on the general laws of mechanics of the movement of liquid and gas:

where P _in , P _out - the actual pressure values at the inlet and outlet of the pipeline, respectively.

The change in gas mass in the first and second chambers of the sensor 3

_rev.1 wherein M ^1, M ¹ _izm.2 - mass of gas in the first and second sensor cells; _Rev.1 P ^1, P ¹ _izm.2 - the pressure in the first and second sensor cells; P ¹ _deist. ¹ - the actual value of the pressure at the inlet to the first sensor chamber, P ¹ _{deyst. 2} - the actual value of the pressure at the outlet of the second sensor chamber.

The change in gas mass in the chambers of the sensor 4

where M ² _{rev 1} , M ² _rev ² - the mass of gas in the first and second chambers of the sensor; _Rev.1 P ^2, P ² _izm.2 - the pressure in the first and second sensor cells; P ² _deyst.1 - the actual value of the pressure at the inlet to the first sensor chamber, P ² _deyst.2 - the actual value of the pressure at the outlet of the second sensor chamber.

The measured pressure at the inlet and outlet of the system corresponds to the measured voltage at the pressure sensors 3, 4. Moreover, each pressure sensor is represented by two equations of pressure change, which is due to the design features of the sensor, in particular the presence of two chambers separated by a membrane. The change in pressure in the sensor chambers is described by the Mendeleev-Klaiperon equation.

The pressure change in the chambers of the sensor 3 is described by the equations

,

- давление в первой и второй камерах датчика, Т - температура газа,

,

- объем газа в первой и второй камерах датчика,

- масса газа в первой и второй камерах датчика, R - молярная газовая постоянная.Where

,

- pressure in the first and second chambers of the sensor, T - gas temperature,

,

- the volume of gas in the first and second chambers of the sensor,

is the mass of gas in the first and second chambers of the sensor, R is the molar gas constant.

The pressure change in the chambers of the sensor 4 is described by the equations

,

- давление в первой и второй камерах датчика, Т - температура газа,

,

- объем газа в первой и второй камерах датчика,

- масса газа в первой и второй камерах датчика, R - молярная газовая постоянная.Where

,

- pressure in the first and second chambers of the sensor, T - gas temperature,

,

- the volume of gas in the first and second chambers of the sensor,

is the mass of gas in the first and second chambers of the sensor, R is the molar gas constant.

The voltage change at the temperature sensor 2 characterizes the heat transfer process between the medium and the sensor. The heat transfer process is determined using the basic laws of heat transfer, characterizes the change in temperature in the medium and is described by the equation

where T _valid - the actual value of the flow temperature, K is a coefficient taking into account the design features of the sensor and the heat transfer mode, T _meas. - the value of the temperature of the medium corresponding to the electrical signal from the measuring device, s - heat capacity of the flow, M _rev. - mass flow.

The voltage at the humidity sensor 5 changes in accordance with the change in humidity described by the Lambert-Bouguer-Baire equation

where I ₀ , I is the intensity of monochromatic radiation at the input and output of a chamber of length l filled with a specific component with a concentration k and spectral absorption coefficient a.

Given the Howard formula

where P _rev. , T _meas. - measured values of pressure and gas temperature in the pipeline flow; R _action , T _valid. - actual pressure and temperature; G - moisture content, A - absorption k - constant, depending on the spectral absorption region.

From the presented equations it is obvious that the parameters have a direct effect on each other in both static and dynamic mode, and the identification of real values in real time in transient operation modes becomes a paramount task in order to ensure the reliability of measurements.

The above expressions (1) - (12) used to process the measurement information of a multicomponent stream with the given coefficients are presented in the normal Cauchy form:

- действительное значение температуры;

,

- действительные значения давления в первой и второй камерах датчика 3;

,

- действительные значения давления в первой и второй камерах датчика 4,

- действительное значение влажности, K₁, K₂, K₃, K₄, K₅, K₆ - коэффициенты алгебраических преобразований.where x ₁ is the measured value of the temperature sensor; x ₂ , x ₃ - measured pressure values in the first and second chambers, respectively, of the sensor 3; x ₄ , x ₅ are the measured pressure values in the first and second chambers of the sensor 4, respectively; x ₆ is the measured humidity value of the sensor 6,

- actual temperature value;

,

- actual pressure values in the first and second chambers of the sensor 3;

,

- the actual pressure values in the first and second chambers of the sensor 4,

- the actual value of humidity, K ₁ , K ₂ , K ₃ , K ₄ , K ₅ , K ₆ are the coefficients of algebraic transformations.

, где

является ошибкой измерения, p_s, c_s - коэффициенты, t - время переходного процесса, который эффективно подавляет большие отклонения измеряемой величины от действительного значения параметра потока за возможно малое время переходного процесса с учетом перевода системы в желаемое состояние при сохранении характерных свойств измерительной системы.To build an algorithm for processing measurement information (Fig. 4), we form an optimizing functional of the form

where

is a measurement error, p _s , c _s are coefficients, t is the transient time, which effectively suppresses large deviations of the measured quantity from the actual value of the flow parameter for the shortest possible transient time, taking into account the transfer of the system to the desired state while maintaining the characteristic properties of the measuring system.

Solving the system of equations (13) describing the mutual influence of the flow parameters relative to the actual values of the flow parameters based on the presented algorithm (Fig. 4), we provide dynamic accuracy of the measured parameters and the speed of obtaining reliable information about the flow parameters in transient modes of flow in the pipeline.

As a result, we obtain the system of equations (14), using which the actual values of the flow parameters, such as temperature, pressure, flow rate and humidity in the pipeline, are revealed at the output of the measuring system.

Presented in figure 5, a simulation model of a measuring system using an algorithm for processing measurement information displays timing diagrams for determining the actual values of the flow parameters.

The proposed method for measuring the parameters of a multicomponent medium is as follows.

Based on the used measuring instruments, using the basic laws of physics, the processes of interaction between the sensors and the flow are described taking into account the dynamic properties of the measuring transducers. A nonlinear system of equations leads to a dimensionless form and is presented in normal Cauchy form. To obtain control laws for each measuring information processing channel, a nonlinear system is linearized at a certain point in time of a steady-state value (transient). For a linear system of equations, the Laplace transforms are used and written in the form of "input - output". In the resulting state matrix, diagonal coefficients are left. To exclude parameters with off-diagonal matrix coefficients, the diagonal coefficients are equal to zero and constitute a system of equations, and for each equation of a linear system a separate system of equations will be obtained, which will be a control for the original system of differential equations. In this case, when determining control signals for each measuring channel, an optimizing functional is determined. The application of classical methods for solving a system of differential equations and the determination of an optimizing functional allows not only to predict the transient during the processing of measurement information, but also to suppress deviations of the measured quantity from the actual value of the flow parameter in a short time of the transient, taking into account the transfer of the system to the desired state while maintaining characteristic properties measuring system.

The multicomponent medium moves along the pipeline 1, in which a temperature sensor 2 is installed to determine the temperature of the medium in the pipeline, for example, ТСП, pressure sensors 3, 4 (at the inlet and outlet of the system), to determine the pressure and flow rate of the medium in the pipeline, for example, “Sapphire”, and a humidity sensor 5 for detecting humidity in the pipeline, for example optical. To process the measuring information, the standard Unit “E14-440” 6 was used. 6. Voltage signals from the primary measuring devices 2-5 for conversion from analog to digital are continuously fed to BOII 6:

from a temperature sensor - information input No. 1;

from pressure sensor No. 1 - information input No. 2;

from pressure sensor No. 2 - information input No. 3;

from humidity sensor - information input No. 4.

The converted signals are continuously used in calculating the actual values of the parameters of the flow 7-10, the calculation of the described values is performed continuously during the measurement using the measuring information processing method (program). The method includes identifying the actual values of the parameters in transition modes of the system, taking into account the interaction according to the above formulas. Conversion, calculation and indication of gas flow parameter values occurs simultaneously.

As the studies show, on the basis of the presented simulation model, the calculation of the values of the flow parameters occurs with a speed an order of magnitude higher than without the algorithm, and the dynamic accuracy of the information obtained in transient flows of flows in the pipeline with an existing set of sensors of the measuring system increases.

Thus, the inventive method of measuring the parameters of multicomponent media in comparison with the known has new properties that can improve the dynamic accuracy of the measurements, and provides speed in transient flows of flows in the pipeline.

Claims (1)

A method for measuring parameters of flowing multicomponent media passing through at least one pipeline, such as medium flow rate, pressure, temperature and humidity using sensors installed in the pipeline rupture, and including transmitting and processing measurement results, characterized in that the measurements are carried out continuously, and the obtained parameter values from each sensor are continuously processed in the measuring information processing unit according to the measurement information processing algorithm taking into account the mutual influence of eryaemyh parameters on each other, the design features of the sensors and the dynamic properties of the transducers.

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