JPS61202150A - Method and device for inspecting heterogeneous transformation process of diffusion motion in turbulence of liquid - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to heterogeneous transformation of diffusive motion occurring during turbulent flow of liquid.
The present invention relates to a method and apparatus for inspecting a process.

[Conventional technology]

There are many processes forming heterogeneous transformation processes occurring in liquids in various technical fields. certain surfaces, such as interfaces between different phases (e.g. in systems consisting of a liquid dispersed phase and a dispersed liquid, gas or solid phase)
Chemical and physicochemical metamorphosis processes that occur at catalytic surfaces, electrodes immersed in liquids, or walls of containers containing liquids are generally classified as heterogeneous transformation processes.

The present invention relates to the examination of such heterogeneous transformation processes occurring in liquids, where the liquid is in a state of turbulence and
Assume that the condition that the process is characterized by diffusive motion is satisfied.

This second condition means that the rate of the transformation process is determined by the rate of mass transport from the internal region of the liquid to and from the surface that is the site of heterogeneous transformation. do.

[Problem that the invention seeks to solve]

To examine the heterogeneous transformation processes that occur in liquids,
Direct testing methods are the most widely used. The essence of these methods lies in sampling and chemical or physicochemical analysis of the sample. Although it is clear that these methods reliably guarantee the accuracy required by practical techniques, it is practically impossible to carry out real-time intervention or control on this basis. In rapidly changing industrial process conditions, direct methods are generally not the solution to control problems. Sampling may be difficult to perform in some cases, especially in processes where sampling is only possible under conditions that shut down the entire process. Another special problem arises in the analysis of components present in small amounts. In this case, one sample will be insufficient and the contents determined for different samples will differ from each other over a wide range including the correct value. Therefore, an analysis based on a large number of samples can only be relied upon to obtain an average value, which is a better way to obtain a correct value the more samples that are analyzed.

Another set of previously known solutions consists of indirect methods, in which the rate or progress of the transformation process is determined based on measured parameters (pressure, temperature, color, sound, etc.) that vary with concentration. Can be inspected. Although the known methods provide the necessary information quickly, their accuracy or reliability is low and does not reach the desired level of control or coordination. For the production of steel, it is known how to carry out interventions in oxygen converters based on acoustic principles (V, 1.Baptizmanski et al., ■■Z 5Thornaya M@tallurg
iyas 1982 No. 2, 34-38 pesos).

The essence of this method is by tracking the acoustic effects and precisely tracking the sound pressure level while blowing oxygen into the molten steel bath.

According to the knowledge presented by the authors, a sudden change in the sound pressure level indicates that the slag coating the molten steel has reached a high density, which is advantageous since the oxygen supply is stopped. Although this measure makes it possible to avoid the occurrence of harmful secondary processes, it is not possible to obtain information that could provide data on changes in the carbon content of the steel bath.

[Means and effects for solving the problem] The aim of the present invention is to avoid sampling and to obtain reliable concentration data for the heterogeneous transformation process of diffusive motion occurring in turbulent flows of liquids. The object of the present invention is to provide such a method and apparatus that indirect measurement methods should be applied.

In the present invention, bubbles (vapour or gas bubbles, cavitation bubbles) that always exist in a turbulent flow of liquid generate a liquid front by their vibration, and the spectral composition of the sound is determined by the turbulent diffusion coefficient that characterizes the transformation process. It is based on the recognition that it remains of well-defined relevance. When the value of the turbulent diffusion coefficient Dturb increases during turbulent flow generation, a characteristic change of the continuous spectrum in front of the liquid occurs. The ratio of the energy content (effective value) allocated to frequency values above a given level to the energy content (effective value) of the lower frequency range in the frequency range actually covered by the spectrum, i.e. turbulent diffusion The higher the coefficient Dturb, the greater the amplitude of the high frequency components of the pre-liquid spectrum compared to the low frequency components. According to this understanding, there exists a time function R(t) which is determined in relation to the turbulent diffusion coefficient Dturb and which has a monotonous functional relationship with the turbulent diffusion coefficient Dturb. Taking advantage of this recognition, it is very important that in the case of a heterogeneous transformation process of the diffusive motion occurring in a turbulent flow of a liquid, a characteristic actual concentration value can be calculated as in the prior art based on the actual value of the turbulent diffusion coefficient. It's advantageous.

To do this, the following data must be known: the starting concentration, the size and time of the surface where the transformation takes place, and/or the concentration if the surface is stable. and, in the case of a transformation involving an equilibrium state, data on the equilibrium concentration, as well as the numerical values of the constants appearing in the rate equation of the transformation.

The purpose of the present invention is to provide a method and apparatus for examining in real time the heterogeneous transformation process of diffusive motion occurring in turbulent flows of liquids, which method and apparatus can be used to It is based on an analysis of the flow and associated acoustic effects. Utilizing the data of the starting concentration values and the active interventions added to the metamorphosis process (e.g. feeding of active material), the present invention provides real-time inspection of processes of the above-mentioned type by detecting acoustic effects. Ensure implementation.

In order to achieve the set objectives, the method and apparatus of the present invention are provided. The essence of the invention is the process of detecting the vibrational process of acoustic frequencies generated by the vibrations of vapor and/or gas bubbles present in a turbulent flow of liquid and reflecting the spectral composition of the detected signal. and forming from that electrical signal a measurement signal reflecting the relative instantaneous value of the turbulent diffusion coefficient of the flowing liquid for indirect real-time testing of the transformation. .

For detection, a microphone or a solid state sound meter can be used. Instead of direct detection, vibration, i.e.
It is advantageous to measure solid-state acoustic effects on liquids when the frequency range is wider than the range of audible sound, and the lack of a gaseous atmosphere to transmit the vibrations that determine the sound causes turbulent liquids to be vacuumed. It is necessary if you want to maintain it inside.

The signal-to-noise ratio, which determines the effectiveness of the detection, is improved by bubbles generated in an additional process, for example by blowing into the liquid a surfactant or a solid powder or gas that vaporizes at the temperature of the liquid. be able to.

The measurement signal can be generated from the detection signal in various ways. The main feature of the measurement signal is that it reflects the spectral composition of the detected signal. One possible method is to choose a reference frequency and thereby divide the vector into two parts. The next step consists in determining the effective value or average value to be assigned to one of the above-mentioned parts and to the whole spectrum, or to both parts, and performing a division on the two values. Generally, the value determined for the spectral range above the reference frequency is divided by the value determined for the entire spectrum or the other range. According to the above understanding, the larger the ratio, the more
The turbulent diffusion coefficient Dturb also increases.

In a further advantageous embodiment of the method according to the invention, the detection signal is spectrally transformed before determining the effective value or the average value. This operation may include filtering noise removal, the essence of which consists in changing the amplitude in one or more spectral ranges, if necessary by substantially canceling some of the spectral ranges. .

Spectral conversion can be performed by a series of narrowband filters, a spectrum analyzer, or a computer connected to an analog-to-digital converter, etc.

The set purpose is to use a detection unit based on acoustic principles,
It can also be achieved by an apparatus capable of implementing the method described above, comprising a series component comprising an amplifier, signal processing means and calculation means, the signal processing means dividing the output signal of the amplifier into spectral ranges. , comprising a circuit for determining a valid value or average value for each range and a ratio of the determined values.

In a preferred embodiment, the signal processing means comprises a circuit arrangement capable of spectrally transforming the output signal of the amplifier.

In the signal processing means of the device according to the invention for carrying out a decision operation, the input filter means as a series of narrowband filters or as a system of low-pass and high-pass filters and optionally one or more It is advantageous to use a multiplication unit, a summing means and an element for determining the effective or average value arranged as two series components, the output terminals of the series components being identified with a time function R(t). is connected to a divider unit which generates a measurement signal to be measured. It is possible that the multiplication unit participates in the spectral conversion operation.

Advantageously, the calculation means are provided with input terminals for supplying constants, calibration data and real-time data.

The method and device according to the invention allows for real-time examination of heterogeneous transformation processes of diffusive motion occurring in turbulent flows of liquids, even containing liquids that are not available for direct examination.

It is therefore used in the conditioning processes required in steel production, used to detect the sulfur content of raw iron, and used to initiate conditioning and intervention actions to achieve a sulfur content in a predetermined range. It is very advantageous. [Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The method according to the invention can be used most advantageously in steel production processes, where the steel is placed in a vessel equipped with an induction mixer. The target set is, for example, to determine the optimal casting point, and to reach this,
Turbulence is the next step in dissolving the alloy material in fine powder form into a container containing steel.

This issue is important because casting operations can begin at melt levels of about 99 degrees. Dissolution is a process of diffusional movement. A solid state sound meter placed above the cover element of the steel vessel detects the acoustic effects associated with the flow.

The acoustic effects are measured in the spectral range from O to 161d(z). It is to exclude from

Those noises with frequencies up to 100 Hz attenuate useful signals. It is therefore advantageous to filter out the frequency range from 0 to 100 Hz. When the amplitude is y and the frequency is X, the function y=y(x) shown in FIG. 1 can be obtained at a predetermined time point. In Figure 1, f=100 Hz is the lower limit of spectral analysis, F-16kHz indicates the upper limit, and H=
5 kHz indicates its reference frequency. Reference frequency H=5
kHz divides the spectrum into two submolecules I and T2.

The essence of the proposed method lies in the analysis of the function (X, ti) determined at time t1 and the evaluation of the changes resulting from the analysis. One of the possible methods for analysis is, for example, the effective value 11 of the spectral part reflecting the molecule l in the frequency range from 100 Hz to 5 kHz.
and the entire frequency range of analysis, i.e. from 100 Hz to 1
6 kl (determination of another effective value I2 reflecting the spectrum of z. The ratio Ir/Is of the two effective values is the time function R
A measurement signal representing the instantaneous value of (t) is provided. Since the transfer function has been previously determined by preliminary measurements, it is possible to calculate the instantaneous value of the turbulent diffusion coefficient Dturb. Based on this value, the feeding time and the feeding amount, a characteristic concentration indicating the progress of the dissolution process can be determined.

Another method is to calculate the ratio Is based on the effective value or the average value
The time function R(t) is determined by tracking the /ItO value. Effective value or average value I! is given as above, and the function 3 is determined by the functions y(x, tt) and z(x). However, z (x) is a spectral transformation function, for example, a monotonically increasing function of the variable X. A good example of this is the function of multiplying the integer part of the ratio x/1000 by 1000. This process is essentially a spectral transformation.

The above-mentioned function z(x) makes it possible to eliminate the influence of amplitudes with frequencies lower than 1000 Hz. The larger the amplitude, the greater the effect.

The intensity of the acoustic effect can be increased by artificially generating air bubbles in a turbulent flowing liquid. Bubbles can be generated by finely divided solid materials that are vaporized at liquid temperatures, or by suitable gases that are introduced or blown into surface-active materials, but do not adversely affect the process. It is obvious that this should be selected. Other methods can also be adopted.

The device proposed according to the invention (FIG. 2) is capable of implementing the above-described method for examining in real time the heterogeneous transformation processes of diffusive motion that generally occur in turbulent flows of liquids. The device produces acoustic effects (sound effects) in turbulent flow of liquids
comprising a detection unit 1 based on acoustic principles for tracking, an amplifier 2, signal processing means 3 for receiving the amplified signal and calculation means 4 for generating an output signal on the basis of the processed signal. do. The calculation means 4 can have input terminals 11, 12, 13 for supplying process characteristic constants and real-time data as well as calibration data.

Naturally, the signal processing means 3 and the calculation means 4 may form a computer with a suitable program, and the output signal of the calculation means 4 will generally be used to detect the process to be detected, for example active materials (lfl ) to a special unit of conventionally known configuration for controlling and/or inspecting the process, such as supplying the mixture, changing the mixing intensity, etc.

The signal processing means 3 include a circuit capable of processing the output signal of the amplifier 2 according to the requirement that the processing should ensure information regarding the process detected by the detection unit 1. In the following, a suitable configuration will be described in relation to operation.

The output signal of the amplifier 2 corresponding to the signal generated by the detection unit 1 is passed through a narrow band filter 6 (
3) or a system consisting of a low-pass filter 15 and a high-pass filter 14 (FIG. 4). The output terminals of the filters are connected to summing means 8 either directly (FIG. 4) or via a multiplication unit 7 (FIG. 3) and further to an element 9 for determining the effective or average value. . These elements are arranged as two series components whose output terminals are connected to a division unit 10 which generates from the output a measurement signal consisting of instantaneous levels providing a time function R(t). The narrowband filter 6 can remove noise at a specific frequency as needed.

The detection unit 1 may be a microphone or a solid-state sound level meter, and its output signal is amplified and then sent to the signal processing means 3.
This is the input signal that should be supplied to the

The calculation means 4 should generate the necessary output signals for displaying the desired data and/or for starting the adjustment or control process.

The present invention will be explained in order to be better understood on the basis of the following examples.

64 tons of molten steel are discharged in the vessel and this amount of metal is to be desulphurized. That is, the sulfur content of the steel must reach a predetermined range. The objective set is achieved by blowing the active material into a stream of an inert gas carrier through a lance immersed in the liquid.

The molten steel is in a turbulent state and also contains cavitation bubbles and gas carrier bubbles. The heterogeneous transformation of the diffusion movement is
It is a reaction that occurs on the surface of dispersed particles that appears due to the reaction between the injected active material and the molten metal. During this transformation process, the sulfur dissolved in the molten steel enters the dispersed particles, which continuously leave the interior space of the molten bath. During this sulfur acceptance reaction, the surface size of the particles remains almost unchanged.

A direction-sensing microphone was used to generate a measurement signal containing the instantaneous value of the time function R(t).

The amplified signal of the microphone is passed through a high-pass filter 14 with a low frequency limit of 7 kHz and a high-pass filter 14 as an output signal of the amplifier 2.
00Hz) is passed through and input to another high-pass filter. The second high-pass filter reliably eliminates noise of low frequencies, in particular in the range of 50 kHz, generated by the operation of a current transformer located adjacent to the vessel containing molten steel. The output terminals of the filter are directly connected to an element 9 which determines the effective value and via them to a division unit 10 which generates an analog signal.

That is, the device generates a signal whose value reflects the energy content assigned to range T2 and the entire spectrum of range T1+T, as shown in FIG. The ratio of these values forms a measurement signal with the instantaneous value of the time function R(t).

In preparation for the testing process, the function relating the time function R(t) to the turbulent diffusion coefficient Dturb, ie the constant appearing in the transfer function of the measurement, was determined. The decision required examination of the desulfurization process in several cases. For this purpose, a photometric flame detector is used before the treatment (using the sample taken from the furnace before casting) and after the treatment (carried out in the stream of steel flowing into the mold).
The sulfur content of the steel was measured using a lame detector. The time function R(t) is calculated from the indicated value of the time function R(t) generated by the device and the photometric analysis data.
It was concluded that the actual sulfur concentration 5(t) can be expressed by the actual kinetic equation in the value range of 0.05 to 0.80.

where E(t) is the equilibrium sulfur concentration. Theoretical studies have shown that the equilibrium sulfur concentration can be expressed by the equation: where So is the sulfur concentration before treatment (casting) and m(t) is the mass of active material injected into the steel at time (t)i of treatment as measured by an electronic balance.

Real-time testing for metamorphosis is performed as follows:
a signal representing the time function R(t) of the device according to the invention;
Nobushima of the device containing Haka υ is processed by a microcomputer that stores the actual form of the motion formula. Sulfur once according to a short time sequence. The actual sulfur concentration S is calculated based on the known value (from sample analysis) of It should be started at this time after removal.

The duration of the inspected process is relatively short, between 3 and
10 minutes, but this time will vary depending on the rate at which the required sulfur content is reached.

The purpose of the test is to produce steel with an acceptable level of sulfur content. However, in order to avoid having to use large amounts of active material, it is important that the sulfur concentration does not fall below the specified lower limit level, since even mildew is harmful.

As the intensity increases, a secondary norocess is initiated which dissolves a relatively high intensity of nitrogen from the air after sulfur □ removal.

The data obtained (by photometric flame analysis of the samples removed after treatment) fully validated the method of the invention. The time function R(
The sulfur content of the sample taken at the value of t) was equal to the sulfur content predicted on the basis of the sample previously analyzed by flame photometry. The results were verified by comparison of 21 measurements carried out with the method and device of the invention with tests according to the prior art (by sampling).

The method and device according to the invention make it possible to test a large number of processes in a relatively simple manner in real time, sample by sample. It is particularly advantageous to be able to determine the value of the turbulent viscosity coefficient and the turbulent thermal conductivity number on the basis of the turbulent diffusion coefficient if certain conditions (reynolds similarity conditions) are met.

Correct results of measurements can only be achieved under conditions of carrying out tests of measurements and calculations, and in some cases tests are necessary during the measurements, but the proposed method and device can achieve the reliability required in real-time processes. It is possible to generate data that can be used to achieve goals that were previously unattainable.

As will be appreciated from the foregoing description, methods and apparatus equivalent to those shown by way of example above are within the scope of the claimed invention, and such methods and apparatus are suitable for different fields of application and It operates under various conditions depending on the given environment.

〔Effect of the invention〕

According to the present invention, it is possible to avoid zanzo ring,
A method and apparatus are provided that allow reliable concentration data to be obtained in real time for diffusive heterogeneous transformation processes occurring in turbulent flows of liquids.

The present invention enables real-time inspection of heterogeneous transformation processes of diffusional motion occurring in turbulent flows of liquids, including liquids that are not available for direct inspection.

[Brief explanation of drawings]

1 shows a possible form of a signal to be processed in the realization of a norocess according to the invention; FIG. 2 is a block diagram of an apparatus according to the invention; and FIG. FIG. 4 shows a preferred embodiment of the circuit used in the signal processing means of the device according to the invention; FIG. (Explanation of symbols) 1... Detection unit, 2... Amplifier, 3... Signal processing means, 4... Calculation means, 6... Narrowband filter, 7... Multiplying unit, 8... ...Total means, 9...
Element, 10... Division unit, 15... Low pass filter.

Claims (1)

[Scope of Claims] 1. A process of detecting vibrations at an acoustic frequency generated by vibrations of bubbles present in a turbulent flow of a liquid; and a process of generating an electrical signal reflecting the spectral components of the detected signal. , forming from said electrical signal a measurement signal reflecting the relative instantaneous value of the turbulent diffusion coefficient of said flowing liquid for indirect real-time testing of heterogeneous transformations occurring in the turbulent flow of the liquid. A method to examine the heterogeneous metamorphosis process of movement. 2. The method according to claim 1, wherein the method includes a step of artificially generating bubbles in the liquid. 3. The method comprises the steps of dividing the detected signal into two spectral ranges, generating the electrical signal reflecting the spectral components, and determining the ratio of the effective or average values of the spectral ranges. Claim 1 or 2
The method described in section. 4. The method according to any one of claims 1 to 3, wherein the method includes the step of spectrally converting the detected signal before generating the electrical signal. 5. Detection unit (1) based on acoustic principle and amplifier (
2), a signal processing means (3), and a calculation means (4), said signal processing means (3) dividing the output signal of said amplifier (2) into spectral ranges. , comprising a circuit for determining characteristic values selected from a group consisting of effective values and average values of each range and the ratio of these values, especially for heterogeneous transformation processes of diffusive motion occurring in turbulent flows of liquids. Equipment for testing the heterogeneous transformation process of diffusional motion that occurs in turbulent flow of liquid. 6. The device according to claim 5, wherein the signal processing means (3) comprises a circuit for forming a spectrum of the output signal of the amplifier (2). 7. The calculation means (4) has input terminals (11, 12) for supplying real-time data, constants and calibration data.
, 13).