KR20240047041A - Coal gasification combined cycle (IGCC) gasifier high temperature and high pressure leak early detection system - Google Patents

Abstract

The present invention is a first and second channel (CH 1, CH) installed with a vibration detection sensor that detects a vibration signal transmitted from the pipe to the external inlet/outlet header of the gasifier for each tube location of the coal gasification combined cycle power plant (IGCC) gasifier. 2) and control to analyze the micro vibration signal (ADC Data) input from the first and second channels (CH 1, CH 2) to identify and store the leakage status and location of the pipe, and transmit it to a remote server. Provides an early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle power plant (IGCC) gasifier, which is characterized by having a device (200).

Description

Coal gasification combined cycle (IGCC) gasifier high temperature and high pressure leak early detection system }

The present invention relates to an early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle (IGCC) gasifier, and more specifically, to the SGCC (Syngas Cooler, synthesis gas heat exchanger) provided inside the IGCC gasifier. This is about an early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle power plant gasifier that can detect leaks in the syngas heat exchange tube consisting of Transfer Duct Tube, Burner Muffle Tube, etc.

Coal-fired power plants used in general coal-fired power plants generate steam using the heat generated by burning coal to turn a steam turbine to produce electricity. Compared to oil and natural gas, coal contains relatively more pollutants such as carbon dioxide and sulfur oxides. There is a problem in that a large amount of NOx is generated due to the high temperature during combustion, and a large amount of SOx is generated when the sulfur contained in coal is burned.

Although there are the above problems, reserves are abundant and production is not concentrated around the world, and 97% of power generation fuel is dependent on imports due to low prices and excellent supply stability. To improve these problems, low-grade raw materials such as coal are gasified. and the Integrated Gasification Combined Cycle (IGCC), which generates power by converting clean fuel gas through a refining process, to be introduced and operated.

However, as shown in Figure 1, while the existing coal-fired boiler can be diagnosed by receiving the noise generated by the leak directly through the membrane wall when a leak occurs in the boiler tube, the gasifier of the coal gasification combined cycle power plant can be diagnosed. As shown in Figure 2, it has a double wall structure of Pressure Vessel Wall and Membrane Wall, and the space between the double walls is filled with nitrogen gas, and inside the Membrane Wall are SGCC (Syngas Cooler, Syngas Heat Exchanger), Transfer Duct Tube, and Burner. Tubes for synthetic gas heat exchange, such as muffle tubes, are provided, so even if a leak occurs in the tube, the leakage noise cannot be transmitted directly to the outer wall (Membrane Wall), so it is impossible to diagnose the leak using the existing LEAK Alam detection method shown in Figure 3. Therefore, as shown in Figure 4, when the transfer duct tube leaks, early detection is impossible after the primary damage, and ash is deposited in the duct, blocking the cross-sectional area of the gas flow path. This reduces the cross-sectional area of the flow path and increases the flow rate of combustion gas, resulting in tube wear. As the damage increases, the problem of secondary damage to multiple tubes occurs.

To solve these problems, it is necessary to develop an early detection system for gasifier high-temperature and high-pressure leakage that detects tube leakage by installing an AE sensor on the outlet header or piping of the heat transfer surface, considering the structure and operating environment of the IGCC gasifier. .

Korean Patent Publication No. 10-1546889 Korean Patent Publication No. 10-2412731 Korean Patent Publication No. 10-2038689

Therefore, the present invention was developed to solve the problems of the prior art as described above. Considering the structure and operating environment of the IGCC gasifier, an AE sensor is installed on the outlet header or piping of the heat transfer surface to detect tube leakage. The goal is to develop an early detection system for gasifier high-temperature and high-pressure leakage that can shorten the maintenance period through early response when equipment problems occur.

The present invention for achieving the above-mentioned object is a first, a vibration detection sensor that detects a vibration signal transmitted from the pipe to the external inlet/outlet header of the gasifier for each tube location of the coal gasification combined cycle power plant (IGCC) gasifier, respectively installed. By analyzing the minute vibration signals (ADC Data) input from the 2 channels (CH 1, CH 2) and the first and second channels (CH 1, CH 2), the leakage status and location of the pipe are identified and stored. , It is an early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle power plant (IGCC) gasifier, characterized by having a control device 200 that transmits to a remote server.

In more detail, the control device 200 includes an amplifier part 210 that performs a hardware signal amplification function for the small vibration signal input from the first and second channels (CH 1, CH 2), and the amplifier part 210 An LPF (Low Pass Filtering) part 220 that converts the signal level of the part 210 to a signal level in the ADC measurement range and simultaneously removes aliasing high-frequency signals that may occur during sampling, and the LPF part 220 ) and is equipped with a Delta-Sigma ADC part (230) that performs secondary anti-aliasing processing after primary anti-aliasing filtering processing.

In addition, based on the FPGA part 240 that controls the Delta-Sigma ADC part 230 to acquire quantized ADC data and stores the data in the internal Dual Port Memory, and the ADC data acquired from the FPGA part 240 It is equipped with a CPU Up Board part 250 that generates parameters for determining the leakage state and leakage location of the pipe by performing a signal processing algorithm.

In addition, the CPU Up Board part 250 generates time wave data and spectrum data for each channel using the micro vibration signal (ADC Data) transmitted from the first and second channels (CH 1, CH 2). And, cross-correlation operation is performed on the filtered-time wave data of channels 1 and 2 generated in the above step to generate cross-time wave data that can determine the mutual similarity of the two channels,

Here, the Cross Correlation formula is

Do this.

In the above formula, f(t) = time axis of sensor 1, g(t) = time axis of sensor 2, τ = time axis, dt = substitution integral formula (f is sensor 1, g is sensor 2, when f is sensor 1, g is the time axis of sensor 1 and sensor 2) It means integration of the phase difference on the time axis of 2, and the relationship between f*g(τ) is interpreted as a formula that adds the phase values of f*g and f(t)g(t).)

Cross-Time Wave Data, which checks the correlation of the two channels, is judged to be a leak if a phase difference between the two signals occurs depending on the degree of delay of the two channels based on the data at the center position.

If it is determined to be a leak above, the time delay difference between the two signals is calculated by applying the vibration propagation speed and sampling rate (96000Hz) for the pipe material. Once the time delay difference between the two signals is calculated, two sensors are installed. Leak location can be tracked by reflecting the actual location distance.

In addition, for tracking the location of the leak, the Timewaveform data generated by performing cross correlation of the first and second channels (CH 1, CH 2) has a reference point at half the number performed (FFT_NUMBER/2), and the reference point is As a standard, the rear indicates the degree to which CH 2 is delayed with respect to CH 1, and the front indicates the degree to which CH2 is ahead of CH1, based on the reference point. Accordingly, based on the number of FFT_NUMBER/2 (the two signal delay point is 0), the maximum If the point where the peak appears is at the back, the CH 2 signal is behind the CH 1 signal (if the leak occurred physically closer to CH 1), and if the point where the maximum peak appears is at the front, the CH 2 signal is behind CH 1. It is judged that the leak occurred before the signal (physically, if the leak occurred at a distance closer to CH 2).

The position where the maximum amplitude appears in the Timewaveform that has passed Cross Correlation is implemented to find left/right based on the FFT_NUMBER/2 point.

The early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle power plant (IGCC) gasifier of the present invention has the advantage of being able to detect tube leakage by installing an AE sensor on the outlet header or piping of the heat transfer surface of the IGCC gasifier.

In addition, it has the advantage of being able to analyze the degree of correlation between the signals of each sensor and track the location of the failure, and can also be applied to leak detection in the high-temperature and high-pressure part of a double-wall structure such as an IGCC gasifier.

Figure 1 is a technical conceptual diagram of a leak detection facility for a conventional coal-fired boiler.
Figure 2 is a double-wall structure of a coal gasification combined cycle power plant (IGCC) gasifier.
Figure 3 shows a leak detector for a coal-fired boiler using a conventional acoustic sensor.
Figure 4 is a process diagram of secondary ripple damage inside the gasifier transfer duct according to the present invention.
Figure 5 is a conceptual diagram of an early detection system for leakage of the high temperature and high pressure part of the IGCC gasifier according to the present invention.
Figure 6 is a configuration diagram of an early detection system for leakage in the high-temperature and high-pressure part of an IGCC gasifier according to the present invention.
Figure 7 is a flowchart of the parameter creation algorithm for the early detection system for high-temperature and high-pressure leakage according to the present invention.
Figure 8 is a graph when a leak occurs at a distance closer to CH 2 than CH 1 in the leak detector of the present invention.
Figure 9 is a graph when a leak occurs at a distance closer to CH 1 than CH 2 in the leak detector of the present invention.
Figure 10 shows a case where the leak occurrence location in the leak detector of the present invention is close to the CH1 Sensor.
Figure 11 shows a case where the leak occurrence location in the leak detector according to the present invention is close to the CH2 Sensor.

With reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification. Additionally, in the case of well-known and well-known technologies, detailed descriptions thereof are omitted.

Throughout the specification, when a part is said to “include” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

Next, an early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle power plant (IGCC) gasifier according to an embodiment of the present invention will be described.

Figure 5 is a diagram showing the configuration of an early detection system for leakage in the high-temperature and high-pressure part of an IGCC gasifier according to an embodiment of the present invention. Referring to FIG. 5, the GCC gasifier high-temperature and high-pressure part leakage early detection system according to an embodiment of the present invention includes first and second channels (CH 1, CH 2), a control device 200, and a display unit each equipped with a vibration detection sensor. Leakage of the evaporator pipe (100) installed inside the structure filled with nitrogen gas between the outer wall (Membrane Wall) and the pressure wall (Pressure Vessel Wall) of the high-temperature and high-pressure part of the GCC gasifier (300) and the double wall (Pressure Vessel Wall) It is possible to detect whether a leak exists in an environment where a barrier exists, and if a leak exists in an environment where a barrier exists, it is also possible to track the location of the leak, improving the reliability of leak detection compared to existing methods.

First, the vibration detection sensors 101 and 102 are installed in a portion of the evaporator pipe 100 extending from the outer wall (Membrane Wall) of the high-temperature and high-pressure section of the GCC gasifier and detect vibration signals transmitted from the evaporator pipe 100. The vibration detection sensors 101 and 102 may be mounted on both sides of the estimated leakage location P in the pipe 100 where leakage is suspected. The vibration detection sensors 101 and 102 may be installed at both ends of the pipe 100 along its longitudinal direction. The vibration detection sensors 101 and 102 can detect a vibration signal that is a mixture of leakage vibration of the pipe 100 and internal vibration of the high-temperature and high-pressure part of the GCC gasifier.

The control device 200 includes an amplifier part 210 that performs a hardware signal amplification function for the slight vibration signal input through the first and second channels (CH 1 and CH 2) of the vibration detection sensors 101 and 102, A low pass filtering (LPF) part 220 that converts the signal level of the amplifier part 210 to a signal level in the ADC measurement range and simultaneously removes aliasing high-frequency signals that may occur during sampling, and the LPF part Through (220), the Delta-Sigma ADC part (230) performs the first anti-aliasing filtering process and then the second anti-aliasing process, and the Delta-Sigma ADC part (230) is controlled to acquire quantized ADC data. An FPGA part 240 that stores data in the internal Dual Port Memory, and parameters that determine the leakage state and location of the pipe by performing a signal processing algorithm based on the ADC data acquired from the FPGA part 240. It is equipped with a CPU Up Board part (250) that generates.

To explain these configurations in detail, the amplifier part 210 is responsible for hardware signal amplification for the micro vibration signal input from the vibration sensor, and the LPF (Low Pass Filtering) part 220 adjusts the signal level to the ADC. Converts to a signal level in the measurement range and simultaneously removes aliasing high-frequency signals that may occur during sampling.

Additionally, the Delta-Sigma ADC part (230) is a 24-bit Delta-Sigma Type ADC, has a high dynamic range of 114dB, and supports a sampling rate of up to 192 kHz. A high-performance Linear Phase FIR Filter is built into the ADC for anti-aliasing filtering, enabling simultaneous sampling of two channels. Anti-aliasing filtering is performed through the internal Delta-Sigma Filtering block and converted to 24-bit digital data. .

In addition, the FPGA part 240 controls the ADC to acquire quantized ADC data and stores the data in the internal Dual Port Memory, and the data stored in the internal Dual Port Memory is moved to the DDR Memory of the CPU Board through CPU Bus Access. ,

The CPU Up Board part (250) performs various signal processing algorithms based on the ADC data acquired from the FPGA to generate parameters to determine the steam leak status of the boiler tube, and then the Local Processor provides external information through PoE (Power of Ethernet). Power is supplied and at the same time, the generated parameter data is transmitted to a remote server including the display unit 300 through the PoE Port.

In addition, when explaining the parameter creation algorithm flow in the software provided in the CPU Up Board part 250, the micro vibration signal (ADC Data) transmitted in the first and second channels (CH 1, CH 2) is used to describe the parameter creation algorithm flow. It has steps for generating time wave data and spectrum data for each channel.

Cross-correlation operation is performed on the filtered-time wave data of channels 1 and 2 generated in the time wave data generation and spectrum data generation steps to generate cross-time wave data that can determine the mutual similarity of the two channels. And

The above Cross Correlation formula is

and

In the above formula, f(t) = time axis of sensor 1, g(t) = time axis of sensor 2, τ = time axis, dt = substitution integral formula (f is sensor 1, g is sensor 2, when f is sensor 1, g is the time axis of sensor 1 and sensor 2) It means integration of the phase difference on the time axis of 2, and the relationship between f*g(τ) is interpreted as a formula that adds the phase values of f*g and f(t)g(t).)

Cross-Time Wave Data, which checks the correlation of the two channels, is judged as a leak if a phase difference between the two signals occurs depending on the degree of delay of the two channels based on the data at the center position.

Additionally, if it is determined to be a leak,

Calculate the time delay difference between the two signals by applying the vibration propagation speed and sampling rate (96000Hz) for the pipe material. Once the time delay difference between the two signals is calculated, it reflects the actual location distance where the two sensors are installed. and track the location of the leak.

To explain this in more detail,

In the above step, it is quantized 24-bit ADC data acquired through FPGA control, and gain adjustment for hardware attenuation is performed on the 24-bit ADC data and multiplied by the bit_resolution (voltage value per 1 bit) value for the 24-bit ADC to obtain Time Wave Raw Data. It is formed through the creation process and the Specturm data generation process consisting of Real and Imaginary by performing FFT using 65536 datasets on Time Wave Raw Data.

In addition, a cross correlation operation is performed on the filtered-time wave data of channels 1 and 2 generated in the above step to generate cross-time wave data that can determine the mutual similarity of the two channels, and the cross correlation formula is Use the formula described above.

Check the location of maximum peak data at the center location of the cross-time wave data generated using the above calculation formula / Leak location can be calculated by reflecting the transmission speed and sampling rate of the vibrating medium, and cross-time wave data that checks the correlation between two channels A phase difference between the two signals is generated depending on the degree of delay of the two channels based on the data at the center position.

In addition, by checking the phase difference between the two signals, the time delay difference between the two signals can be calculated by applying the vibration propagation speed to the medium and the Sampling Rate (96000Hz). The time delay difference between the two signals is calculated. If so, the leak location can be tracked by reflecting the actual location distance where the two sensors are installed.

As shown in Figures 8 and 9, the Timewaveform data generated by performing cross correlation of sensors with sensors installed in both directions and designating sensor number 1 as CH1 and sensor number 2 as CH2 is half of the number performed (ex. FFT_NUMBER/ 2) The point becomes the reference point.

Based on the half position, the rear indicates the degree to which CH2 is delayed with respect to CH1, and the front part relative to the half position indicates the degree to which CH2 is ahead of CH1, based on the number of FFT_NUMBER/2 (the two signal delay point is 0) ) If the point where the maximum peak appears is behind the CH2 signal, the CH2 signal is behind the CH1 signal. (Physically, this is the case when the leak occurs at a distance closer to CH1.)

If the point where the maximum peak appears is in front, it means that the CH2 signal is in front of the CH1 signal. (Physically, this is the case when the leak occurs at a distance closer to CH2.)

In addition, the position where the maximum amplitude appears in the Timewaveform that has passed Cross Correlation is implemented to find left/right based on the FFT_NUMBER/2 point and applied to the IGCC gasifier boiler. Leak occurs in a structure where existing equipment (BTLD) cannot be used due to double walls. can be detected and the location of occurrence can be found.

If the location of the leak is close to the CH1 Sensor, as shown in Figure 10, the vibration signal is received with a time delay of b toward the CH2 sensor, and the time delay calculated through the correlation operation becomes the value of b. At this time, the b value is generated as a positive real number, and the leak occurrence location can be known as a = [L - b] / 2.

On the other hand, when the location of the leak is close to the CH2 sensor, as shown in Figure 11, the vibration signal is received with a time delay d further toward the CH1 sensor, and the time delay value calculated by the correlation operation becomes the value d. However, the d value is generated as a negative real number. Leak occurrence location c = [L - d] / 2, and the leak occurrence location away from CH1 relative to CH1 can be known as = L - c.

Although the present invention has been described in detail through specific examples, this is for detailed explanation of the present invention, and the present invention is not limited thereto, and can be understood by those skilled in the art within the technical spirit of the present invention. It is clear that modifications and improvements are possible.

All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

100: Piping 101, 102: Vibration detection sensor
200: Control device 210: Amplifier part
220: LPF part 230: Delta-Sigma ADC part
240: FPGA part 250: CPU Up Board part
300: display unit
[abbreviation]
BTLD: Boiler tube leak detection system
Membrane Well: Wall inside the boiler
IGCC: Integrated Gasification Combined Cycle (Coal Gasification Combined Cycle Power Plant)
Pressure Vessel Wall: Wall outside the boiler.
Cross Correlation:
Leak: A symptom that appears when the evaporator tube bursts or cracks.
LP: A device that receives, amplifies and transmits vibration signals
RECEIVE UNIT: Receiving device
Acoustic: acoustics
SGCC: Syngas heat exchanger
Logic: logical flow
FPGA: field programmable gate array (semiconductor device with designable logic elements and programmable internal circuitry)
RTC: Real Time Clock
RS-232: RS-232 (Recommended Standard 232) is a standard introduced in 1960 and is a serial interface that connects a PC, audio coupler, modem, etc.
PoE: Power Of Ethenet A networking feature defined by the IEEE 802.3af and 802.3at standards. PoE allows you to power network devices over an Ethernet cable over an existing data connection.
Analog: Expressing a numerical value as a physical quantity that changes continuously due to external causes, such as 'length', 'angle', or 'current'.
Digital: A method of processing analog using discrete numbers with a specific minimum unit, rather than continuous real numbers.
LPF: Low Pass Filtering A low-pass filter refers to a filter that attenuates signals with frequencies above a specific cutoff frequency and passes only signals with frequencies below the cutoff frequency.
Anti-Aliasing Filtering: Low-pass filter
ADC: Analog-to-digital converter Electronic circuit that converts analog electrical signals into digital electrical signals
Dynamic range: The ratio between the maximum and minimum values that can estimate a specific quantity.
Linear Phase FIR Filter: A filter capable of linearizing the phase response.
bit: sign of data
Dual Port Memory: A type of RAM that allows multiple reads or writes simultaneously.
Access: Permission or assigned permission to use computer data or resources in any way.
Parameter: In mathematics and statistics, a parameter refers to a variable that represents a specific characteristic of a system or function.
Imaginary: A complex number that is not a real number
Spectrum: A continuous arrangement of wave components according to frequency.
Overall RMS: Power sum of amplitudes for each frequency shown in the spectrum as an additional unit of rms
Octave Band: This refers to the frequency range where the frequency is twice the difference.
DB: DataBase refers to a collection of data that is integrated and managed.
ADC = Analog to Digital Converter
FFT = Fast Fourier Transform
IFFT = Inverse Fast Fourier Transform
LPF = Low Pass Filtering
PoE = Power of Ethernet
L: Distance between sensors
d: Distance between sensors - sensor value closest to the location where the nick occurred * 2
b: Distance between sensors - sensor value closest to the location where the nick occurred * 2
a: Distance from nick to the nearest sensor
c: Distance from nick to nearest sensor

Claims (4)

The 1st and 2nd channels (CH 1, CH 2) and the 1st and 2nd channels (CH 1, CH 2) respectively have vibration detection sensors that detect vibration signals transmitted from the pipe to the external Inlet/Outlet Header of the gasifier for each tube location of the coal gasification combined cycle power plant (IGCC) gasifier. ,
A control device (200) that analyzes the micro vibration signal (ADC Data) input from the first and second channels (CH 1, CH 2), identifies and stores the leakage state and location of the pipe, and transmits it to a remote server. An early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle power plant (IGCC) gasifier, characterized by having a. According to paragraph 2,
The CPU Up Board part (250) is
Amplifier part 210 that performs a hardware signal amplification function for the small vibration signal input from the first and second channels (CH 1, CH 2),
An LPF (Low Pass Filtering) part 220 that converts the signal level of the amplifier part 210 to a signal level in the ADC measurement range and simultaneously removes aliasing high-frequency signals that may occur during sampling,
A Delta-Sigma ADC part (230) that performs primary anti-aliasing filtering through the LPF part (220) and then secondary anti-aliasing processing,
An FPGA part (240) that controls the Delta-Sigma ADC part (230) to acquire quantized ADC data and stores the data in an internal Dual Port Memory;
Characterized by having a CPU Up Board part 250 that generates parameters for determining the leakage state and leakage location of the pipe by performing a signal processing algorithm based on the ADC data acquired from the FPGA part 240. Early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle power plant (IGCC) gasifier. According to paragraph 1,
The control device 200 is
Generating time wave data and spectrum data for each channel using the minute vibration signals (ADC data) transmitted from the first and second channels (CH 1, CH 2);
Cross-correlation operation is performed on the filtered-time wave data of channels 1 and 2 generated in the time wave data generation and spectrum data generation steps to generate cross-time wave data that can determine the mutual similarity of the two channels. And
The above Cross Correlation formula is
and
In the above formula, f(t) = time axis of sensor 1, g(t) = time axis of sensor 2, τ = time axis, dt = substitution integral equation, (f is sensor 1, g is sensor 2, and g is the time axis of sensor 1 It refers to the integration of the phase difference on the time axis of sensor 2, and the relationship between f*g(τ) is interpreted as a formula that adds the phase values of f*g and f(t)g(t).)
Cross-Time Wave Data, which checks the correlation of the two channels, is judged as a leak if a phase difference between the two signals occurs depending on the degree of delay of the two channels based on the data at the center position.
Additionally, if it is determined to be a leak,
Calculate the time delay difference between the two signals by applying the vibration propagation speed and sampling rate (96000Hz) for the pipe material. Once the time delay difference between the two signals is calculated, it reflects the actual location distance where the two sensors are installed. An early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle power plant (IGCC) gasifier, which is characterized by tracking the location of the leak. According to paragraph 3,
Tracking the location of the leak is
For the Timewaveform data generated by performing cross correlation of the first and second channels (CH 1, CH 2), the reference point is half of the number performed (FFT_NUMBER/2),
Based on the above reference point, the back side indicates the degree to which CH 2 is delayed with respect to CH 1, and the front side relative to the reference point represents the degree to which CH2 is ahead of CH1, so based on the number of FFT_NUMBER/2 (two signal delay 0 point ) If the point where the maximum peak appears is at the back, the CH 2 signal is behind the CH 1 signal (physically, if the leak occurred at a closer distance to CH 1), and if the point where the maximum peak appears is at the front, the CH 2 signal is behind the CH 1 signal. It is judged to have occurred before the CH 1 signal (physically, if the leak occurred at a closer distance to CH2),
An early detection system for leakage in the high-temperature, high-pressure part of a coal gasification combined cycle power plant (IGCC) gasifier, which is characterized by finding the position where the maximum amplitude appears in the Timewaveform that has passed Cross Correlation to the left and right based on the point FFT_NUMBER/2.