JPH0220688B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention measures the descending velocity distribution of a charge and the gas flow velocity distribution at the mouth of a blast furnace in order to improve the stable operation and productivity of a blast furnace. Regarding equipment.

[Prior Art and its Problems] In the prior art, there is no device that simultaneously measures the descending velocity distribution of the charge and the gas flow velocity distribution at the mouth of the blast furnace, so individual prior art will be explained.

As a device for measuring the rate of descent of the charge, for example,
This method is disclosed in JP-A No. 58-37107, a method for measuring the descending state of blast furnace charge, in which a weight attached to the tip of the wire is made to follow the descending of the charge, and the payout of the wire at this time is measured. The rate of descent of the charge is calculated from the amount. This method has the following problems.

Since the top surface of the charge in the blast furnace is sloped, and the charge itself has a complicated uneven shape, the weight may slip on the charge, reducing measurement accuracy. or,
First, it is necessary to lower the weight onto the surface of the charge so that the wire does not come loose, and to improve measurement accuracy, measuring with multiple weights can avoid the problem of wires getting entangled with each other. However, the workability was not good.

As another measurement method, according to the materials of the 68th Pigmaking Subcommittee of the Japan Iron and Steel Institute Joint Research Group, a method of measuring the descent speed using a laser profile meter has been reported. However, with this method, it is difficult to measure immediately after the charge is inserted due to scattering of the laser light by dust in the blast furnace, and the measurement accuracy is ±30
mm, whereas the rate of descent of the charge is approximately 1.5 mm.
Since the measurement speed is very slow (mm/s), it is necessary to lengthen the measurement time to obtain high measurement accuracy, and there was a problem in that the charging of the charge had to be stopped during that time.

As a gas flow rate measuring device, for example, JP-A-56-
It is disclosed in No. 102504, Method for Measuring Flow Velocity of Blast Furnace Mouth Gas. This measuring device is equipped with a supply nozzle that supplies a gas jet horizontally to a lance inserted horizontally into the furnace wall, and two pressure detection nozzles that are provided to face this nozzle. Then, due to the deflection of the gas jet injected from one supply nozzle by the gas in the furnace, a difference occurs between the pressures detected by the other two detection nozzles, and the gas flow velocity at the furnace mouth is determined from this differential pressure. ing. However, such a measurement method has the following problems.

Measurement errors are likely to occur for gas flows that have components in the same direction as the gas jet, and if multiple units are installed to determine the gas flow distribution in the radial direction of the furnace, disturbances may occur to the gas flow at the furnace mouth, resulting in errors. Summer.

Other measurement methods include a turbine-type flowmeter using an impeller and a thermal flowmeter, but both deteriorate rapidly in the blast furnace, where there is a lot of dust under high temperature and pressure, and maintenance work becomes complicated.

[Problems to be Solved by the Invention] As described above, the conventional measurement methods for measuring the drop rate distribution and the furnace mouth gas flow rate distribution tend to deteriorate under high temperature and high pressure, and have poor accuracy. The present invention provides a highly durable blast furnace furnace mouth measuring device that can simultaneously detect the descending rate of the charge and the gas flow rate distribution at the furnace mouth with high precision and non-contact measurement. The purpose is to provide.

[Means for Solving the Problems] The blast furnace mouth measurement device of the present invention includes a lance that can be driven in the furnace radial direction at the blast furnace mouth, and a lance that can be stopped at a predetermined measurement point. a lance drive control device, and a plurality of units installed in the lance that transmit microwaves to the charge and dust in the furnace and receive reflected waves from the charge and dust. a microwave antenna, a microwave generation circuit that supplies microwaves to the microwave antenna, and a microwave detection circuit that performs mixed detection of a transmitted wave from the microwave generation circuit and a received wave from the microwave antenna; filter means for extracting high-frequency and low-frequency signal components from the components of the Doppler signal obtained by the micro-detection circuit; and filter means for detecting the frequency of the low-frequency signal components obtained by the filter means, A charging material descending speed detection circuit outputs a signal corresponding to the descending speed of the charged material, and a charge material descending speed detection circuit that detects the frequency of a high-frequency signal component obtained by the filter means and converts the rising speed of the dust material. and a gas flow velocity detection circuit that outputs a signal corresponding to the furnace mouth gas velocity.

[Operation] According to the above configuration, the microwave from the microwave generation circuit is transmitted from the microwave antenna to the charge and the dust. Then, the transmitted microwave is reflected by the charge or dust, and the reflected wave is received by the microwave antenna. This received reflected wave and a part of the transmitted wave supplied to the microwave antenna are mixed and detected by a microwave detection circuit, and have a signal component with a frequency corresponding to the moving speed of the charge or dust object. A Doppler signal is output. This Doppler signal is
The filter means extracts the signal as high-frequency and low-frequency signal components. These two signals are detected by the charge descending speed detection circuit and the gas flow velocity detection circuit, respectively, to determine the desired descending speed signal, the dust movement speed,
That is, a signal indicating the gas flow rate is obtained.

[Example] FIG. 1 shows one embodiment of the invention.

1 indicates the side wall of the blast furnace; 2 indicates the side wall 1;
This is a lance that injects gas etc. by penetrating the furnace in the horizontal direction, and the lance 2 part located inside the furnace body has three reflector horn antennas 3.
Three a, 3b, and 3c are provided at equal intervals.
Furthermore, a microwave transmission window a is provided in the opening A of each antenna to prevent dust from entering the horn antenna portion, and the material thereof may be, for example, quartz glass. 4 is a microwave generation circuit for supplying microwaves to the horn antennas 3a, 3b, and 3c, and this microwave generation circuit 4 and each horn antenna 3
a, 3b, 3c are waveguides 5a, 5b, respectively.
5c. 6a, 6b, 6c are signal processing circuits provided corresponding to the horn antennas 3a, 3b, 3c, respectively. A Doppler signal obtained by mixed detection of the received signal and the signal generated by the microwave generation circuit 4, that is, the transmitted signal from each horn antenna 3a, 3b, and 3c, is input.

In the signal processing circuit 6a, 61 is an amplifier that amplifies the Doppler input signal, 62 is a low-pass filter that extracts a low-frequency signal component from the signal from the amplifier 61, and 63 is a low-pass filter that extracts a low-frequency signal component from the signal from the amplifier 61. This is a period measurement circuit for detection. 64 is an average value calculation circuit for calculating the average value of the obtained frequencies, and 65 is a speed conversion circuit for converting the average value of the obtained frequencies into the descending speed of the charge. Further, 66 is a high-pass filter that extracts a high-frequency signal component of the signal from the amplifier 61, and 67 is a comparator that extracts a signal of a predetermined strength from the obtained high-frequency signal component. be. 68 is an FV converter that converts the input frequency signal into a voltage value, and 69 is a constant multiplication circuit that multiplies the converted voltage value by a predetermined constant in order to obtain the gas flow velocity.

Next, the micro generating circuit 4 will be explained in detail with reference to FIG. 2.

21 is a microwave oscillator that oscillates microwaves, and the oscillated microwaves are sent to a splitter 23 via an isolator 22 that transmits signals in one direction.
a, 23b, and 23c, and the energy is divided equally. The circulator 24a, into which the signal from the splitter 23a is input, supplies the horn antenna 3a via the stub tuner 25a, which is a matching box, and the waveguide 5a, and connects the supplied microwave with the horn antenna 3a. The transmitted microwave is mixed with the received wave and sent to the detector 26.
Send to a. The detector 26a performs mixed detection of the transmitted wave and a received wave that is shifted from the transmitted wave by the time the microwave travels back and forth between the horn antenna 3a and the top surface of the charge. Therefore, this detector 26a
The frequency of the Doppler signal obtained in corresponds to the change in the distance between the horn antenna 3a and the top surface of the charge, and in this case, since the horn antenna 3a is held at a constant height, the frequency of the Doppler signal will indicate a change in the charge level.
This Doppler signal is sent to the signal processing circuit 6a as described above. Since the duplexers 23b, 23c and subsequent parts have the same circuit configuration as the duplexer 23a, the description of the circuit configuration and the following operation will be omitted.

Next, the operation of the measuring device having the above configuration will be explained.
The microwave oscillated by the microwave oscillator 21 is supplied to the horn antenna 3a by the function of the circulator 24a. Horn antenna 3a
Then, by supplying microwaves, the microwaves are transmitted to the charge, and the microwaves reflected by the charge are received and sent to the circulator 24a. The circulator 24a mixes a part of the transmitted wave supplied to the horn antenna 3a and the received wave sent from the horn antenna 3a, and sends the mixture to the detector 26a. As a result, the detector 26a
As described above, a Doppler signal having a frequency corresponding to the level of the charge is outputted from the doppler signal processing circuit 6a, and sent to the signal processing circuit 6a.

In the signal processing circuit 6a, after being amplified by an amplifier 61, a low-pass filter 62 and a high-pass filter 66 extract a low-frequency signal and a high-frequency signal. The frequency of the low frequency signal is directly detected by the period measurement circuit 63, and the detected frequencies are averaged by the average value calculation circuit 64. After that, the speed conversion circuit 65
It is converted into a value that is the descending speed of the charge.

On the other hand, the high-frequency signal obtained by the high-pass filter 66 is first extracted at a predetermined level by a comparator 67, and then sent to the FV converter 6.
After being converted into a voltage value corresponding to the frequency in step 8,
A constant multiplier 69 multiplies by a predetermined constant that corresponds to the gas flow rate in the furnace.

In this way, as can be seen from the positional relationship in FIG. 1, the descending velocity and gas flow velocity obtained by the horn antenna 3a are the results at a location close to the side wall 1 of the furnace, whereas the measurement results by the horn antenna 3c are , the measurement results were obtained at a location close to the center of the blast furnace. Furthermore, by moving the lance 5 in the horizontal direction using a lance drive device (not shown), it is possible to obtain, for example, the descending velocity and gas flow velocity at the center of the charge, and the distribution of the descending velocity and gas flow velocity can be easily determined. Can be done. Incidentally, since the numerical values of the descent speed and the gas flow rate differ by more than two orders of magnitude, signal separation by the low-pass and high-pass filters 62 and 66 is easy.

Figure 6 shows the results of measuring the actual descent speed and gas flow velocity using this device, and the frequency of the microwave used in this device was 24.1GHz.
Transmission power was 10mW. As can be seen from FIG. 6, the rate of descent of the charge increased toward the center, while the gas flow rate reached a relatively high rate in the core.

FIG. 3 shows the micro generation circuit 6 shown in FIG.
This shows another embodiment of the circuit, in which the same parts as in the circuit of FIG. 2 are given the same reference numerals. Third
In the figure, by providing a microwave switch 27 that can switch between three circuits between the stub tuner 25 and the waveguides 5a, 5b, and 5c, three systems are provided in each of the microwave generation circuit 4 and the signal processing circuit 6. There is an advantage that you can do without it.

4 and 5 show another method of attaching the horn antennas 3a, 3b, 3c to the lance 2. In Figure 4, the horn antenna 4
1a, 41b, and 41c have a conical shape, and the horn portion is vertical. By adopting such a shape, dust does not accumulate in the horn portion, so the microwave transmission window 42 does not need to be provided at the opening of the horn, but a small one is provided inside the waveguides 5a, 5b, and 5c. be able to.

In FIG. 5, the antennas are simply holes 51a, 51b, and 51c having openings at the bottom. In this case as well, there is no risk of dust accumulation, so the microwave transmission window 52 is connected to the waveguides 5a, 5b,
5c.

[Effects of the Invention] According to the present invention, microwaves reflected from a charge etc. are detected as a Doppler signal, and from the content of the Doppler signal, the descending speed of the charge and the velocity of dust, that is, the gas flow rate can be determined. This makes it possible to perform non-contact measurement with high precision and good responsiveness. Furthermore, since the detection is performed without contact, the detection element does not deteriorate even inside the furnace under high temperature and high pressure, and high accuracy can be maintained over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a measuring device that is an embodiment of the present invention, FIG. 2 is a block diagram showing details of the microwave generation circuit in FIG. 1, and FIG. 4 and 5 are block diagrams showing another embodiment of the microwave generation circuit.
FIG. 6, which shows another form of the horn antenna in the lance shown in the figure, is a diagram showing the results of actual measurements using the apparatus shown in FIG. 1. 1...Furnace side wall, 2...Lance, 3a, 3b, 3
c...Horn antenna, 4...Micro generator circuit, 5a, 5b, 5c...Waveguide, 6a, 6b,
6c...Signal processing circuit, a...Micro transmission window,
21... Micro oscillator, 22... Isolator, 23a, 23b, 23c... Duplexer, 24
a, 24b, 24c... Circulator, 25
a, 25b, 25c...Stubchyuna, 26
a, 26b, 26c...detector, 27...microwave switch.

Claims (1)

[Claims] 1. A lance that can be driven in the radial direction of the furnace at the mouth of the blast furnace, a lance drive control device that can stop the lance at a predetermined measurement point, and a lance that is provided within the lance. , a plurality of microwave antennas that transmit microwaves to the charge and dust in the furnace and receive reflected waves from the charge and the dust; A microwave generation circuit that supplies a microwave, a microwave detection circuit that performs mixed detection of the transmitted wave from the microwave generation circuit and a reception wave from the microwave antenna, and a microwave detection circuit that detects a high filter means for extracting signal components in the low frequency range and the low frequency range, and a charging device for detecting the frequency of the signal component in the low frequency range obtained by the filter means and outputting a signal corresponding to the descending speed of the charge. A material descending speed detection circuit and a gas flow rate that converts the rising speed of the dust material obtained by detecting the frequency of the high frequency signal component obtained by the filter means and outputs a signal corresponding to the gas velocity at the furnace mouth. What is claimed is: 1. A blast furnace mouth measuring device comprising: a detection circuit; 2. The blast furnace mouth measurement device according to claim 1, wherein the plurality of microwave antennas are located in the radial direction of the furnace.