JPH0234603Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an apparatus for measuring the moisture content of coke charged into a blast furnace during blast furnace operation.

(Prior Art) Coke charged into a blast furnace during blast furnace operation contains a certain amount of moisture, and at the stage of determining the amount to be charged, the moisture value is corrected and the coke is charged into the blast furnace.
That is, in the reaction inside the blast furnace, it is extremely important to accurately charge coke into the blast furnace that is appropriate for the charged raw materials (sintered ore, ore, etc.).

The reason for this is that coke plays an extremely important role in the reduction reaction and air permeability in the furnace, and also as a heat source, and a lack of coke will lead to deterioration of the furnace condition. The unit consumption rate increases, resulting in large economic losses. Therefore, it is necessary to charge an appropriate amount of coke commensurate with the raw material. Therefore, before charging the coke into the blast furnace, the coke is weighed using a highly accurate weighing device and charged into the furnace.

By the way, coke is generally produced by carbonizing coal in a coke oven and cooling the red-hot coke by pouring a large amount of water over it, so coke contains about 10% water. When coke containing water is weighed in this way, the weight of coke will include the weight of water, and the amount of coke will not be correct. Therefore, the net weight of the coke must be determined by measuring the moisture in the coke and correcting it based on the moisture content. FIG. 2 shows a conventional and commonly used apparatus for measuring the moisture content of coke. In the figure, coke 3 is temporarily stored and measured in a relay hopper 1. At this time, the water content is measured by a neutron moisture meter 2 attached to the side surface of the coke hopper 1. A neutron moisture meter utilizes the property that neutron beams emitted from a neutron source are attenuated by the moisture contained in coke.It measures the moisture content of coke within the reach of neutrons, and calculates the amount of coke in the coke hopper from this moisture content. Moisture is being calculated.

(Problems that the invention attempts to solve) Therefore, there are some disadvantages when using a neutron moisture meter. One drawback is that the range of the neutron beam is at most 2 meters, and it can only measure the moisture content of the coke immediately in front of the measuring device. On the other hand, the diameter of the coke hopper is 8 m, and the measured moisture value does not necessarily accurately indicate the moisture value of the entire coke stored in the coke hopper. One other drawback is
As you can see from the installation state of the neutron moisture meter in the figure, when rainwater enters, the water droplets travel down the side wall of the coke hopper, forming a water film on the front of the neutron moisture meter. Since the film is also included in the coke moisture value, an extremely large error occurs. Therefore, as disclosed in Japanese Patent Application Laid-Open No. 52-58991, a device for sampling a portion of the charged coke is installed in the middle of the raw material path leading to the coke hopper, and at the end of this sampling device, a device suitable for measurement with a neutron moisture meter is installed. Most of the above-mentioned drawbacks can be overcome by providing a sampling hopper with a volume and equipping this sampling hopper with a neutron moisture meter to analyze moisture. However, since samples are collected into the sampling hopper only once each time raw materials are charged into the hopper, the moisture content is only measured on a portion of the total coke that is actually used. The moisture content of the entire coke produced will not be measured.

On the other hand, there is another moisture measurement method that uses infrared rays to measure surface moisture, but this method can only measure the moisture content of the surface layer of coke in the hopper, so the measured value does not accurately reflect the moisture content of the entire coke. It is not meant to be shown. Also, JP-A-57-42837
The issue describes a device that uses an infrared moisture meter to measure the moisture content of coal and coke, but since the moisture content is measured by extracting a portion of the coke on the conveyor, it is a batch method and is difficult to operate. It's complicated.

Furthermore, during measurement, it is necessary to keep the distance from the infrared light emitting section to the surface of the object to be measured constant, and to keep the particle size of the object to be measured constant. Therefore, infrared moisture meters are generally used in steel factories to measure the moisture content of sintered raw materials whose particle size is adjusted to 5 mm or less, but the shape, color, particle size, chemical composition, etc. It has the property of showing different values even if the moisture content is the same when it changes. Infrared moisture meters can be used to detect coke, such as sintered raw materials, that are mixed with coarse grains with a particle size of 20 to 50 mm and have greatly different particle sizes, compared to so-called grain size-adjusted raw materials that are charged to a blast furnace. Because it is greatly affected by the surface condition and particle size of coke, it is necessary to recalibrate each time the properties of coke change, so infrared moisture meters are now commonly used to measure moisture in coke, unlike in the case of sintered raw materials. It has not been.

The purpose of this invention is to provide a coke moisture measuring device that can eliminate and improve the conventional drawbacks and problems, and to provide a coke moisture measuring device as described in the claims for utility model registration. The above objective can be achieved by the following. That is, this invention is an apparatus for measuring the moisture content of coke that is conveyed to the top of a hopper by a belt conveyor and charged into the hopper, which includes an infrared moisture meter disposed on the belt conveyor that extends to the top of the hopper, and the belt. A sampling conveyor for automatic sample collection, which is provided below the coke discharge end of the conveyor and above the hopper charging port, and which is movable forward and backward; and a sampling conveyor located at the discharge end of the sample collected by the sampling conveyor. , a sampling hopper to which a neutron moisture meter is attached, and a calculation device that synchronizes the neutron moisture meter and the infrared moisture meter and calibrates the measured value of the infrared moisture meter with the measured value of the neutron moisture meter. The present invention relates to a moisture measuring device for coke charged into a relay hopper provided therein.

(Means for Solving the Problems) The coke moisture measuring device of the present invention will be described below. FIG. 1 is an explanatory diagram showing an embodiment of the coke moisture measuring device of the present invention. As shown in the figure, the apparatus of the present invention includes a coke hopper 1 for charging coke 3 into a blast furnace, a belt conveyor 4 for conveying coke 3 to the coke hopper 1, and a lower part of the discharge end of the belt conveyor 4. There is a sampling belt 5 which can move forward and backward and can move forward and collect a part of the coke that falls from the belt conveyor 4 into the hopper 1. The coke 3 collected by the sampling belt 5 enters a sampling hopper 6. A neutron moisture meter 2 is provided on the side wall of the sampling hopper 6. The sampling hopper 6 has a volume and structure that is within the effective range of the neutron beam source, and most of the coke 3 stored in the sampling hopper 6 is within the range of the neutron beam of the neutron moisture meter 2. It is configured as follows. Coke 3 is placed above the belt conveyor 4 that carries raw materials into the hopper 1.
An infrared moisture meter 7 that emits infrared rays toward is arranged. Infrared moisture meter (infrared moisture meter)
This method takes advantage of the fact that water has a large absorbance at a specific wavelength of infrared rays, and FIG. 3 is a diagram showing the relationship between the wavelength and transmittance of water. Water has a large absorption band near the wavelength of 1.94 μm for near-infrared rays. Using a calibration curve showing the relationship between this absorbance and moisture value, a converted moisture value is determined from the absorbance in this wavelength band.

FIG. 4 shows an explanatory diagram of a reflection type infrared moisture meter used for measuring moisture in coke. This infrared moisture meter includes a rotary plate 13 equipped with a light emitting lamp 10, a condensing lens 11 that focuses the light beam, an optical filter 12 that selects a specific wavelength, and a rotating plate 13 that reflects the light that has passed through the optical filter 12 and 14, a condensing mirror 16 that condenses the reflected light reflected from the object to be measured 14, and a light receiver 17 that converts the condensed light into an electrical signal.
The rotating plate 13 has a measurement wavelength corresponding to the absorption band of water.
In addition to the filter that transmits 1.94 μm, one or more filters that transmit comparative wavelengths unrelated to water absorption are installed and rotated at a constant speed by a rotation motor 18. Furthermore, an amplifier 19 for processing the electrical signal from the optical receiver 17, a synchronous detector 20,
A light emitting diode 21 for extracting a synchronization signal, a light receiver 22, a measurement signal holding circuit 23, comparison signal holding circuits 24 and 25, an averaging circuit 26, and a computing unit 27 are provided. This infrared moisture meter measures moisture by condensing reflected light B of light A incident on the object to be measured 14, and the reflected light B is converted into an electrical signal by a light receiver 17. The rotary plate 13 has a filter 12 with a wavelength corresponding to the absorption band of water and a filter that transmits a comparative wavelength unrelated to the absorption band of water, and rotates at a constant speed, so that the object to be measured 14 receives light of these wavelengths. A is incident in order, and reflected light B, which is reflected light from the surface and inside of the object to be measured 14 and scattered light, is input in order to the light receiver 17, so that the luminous intensity of a specific wavelength based on the presence of moisture and the comparison wavelength are The moisture content of the object to be measured 14 can be measured from the calibration curve by comparing the luminous intensity with the luminous intensity of . That is, the signal from the light receiver 17 passes through the amplifier 19 to the light emitting diode 21 and the light receiver 2.
The signal is input to the detector 20 which is synchronized based on the synchronization signal composed of 2. The synchronously detected signals are passed through a measurement signal holding circuit 23, comparison signal holding circuits 24 and 25, and an averaging circuit 26 to a computing unit 27.
is input and the moisture value is calculated.

By the way, when using an infrared moisture meter to measure the moisture content in raw ore, the calibration method when different types are used is to install a rotating plate at a position where the optical path from the infrared emitter can be blocked, and to set an opening in this rotating plate. , the light from the light emitting unit can directly reach the object to be measured through the opening, a calibration sample is placed on the blocking surface other than the opening, and the rotary plate is rotated at appropriate intervals to perform calibration with known moisture content. A reference value is obtained by placing a sample in the optical path, and the measured values are calibrated using this reference value.

In this invention, by applying the large neutron moderating ability of hydrogen atoms, moisture values can be accurately measured without being affected by the shape, particle size, color tone, etc. of the object to be measured.
We attempted to accurately determine the moisture content in coke by using both a neutron moisture meter, which faces downward for continuous measurement, and an infrared moisture meter, which is suitable for continuous measurement but is easily affected by the shape and particle size of the object to be measured. It is something to do. In other words, according to the device of the present invention, an infrared moisture meter is installed above the belt conveyor, and all of the raw materials fed into the hopper can be measured, so the measurement results are averaged and the amount of charged raw materials can be measured. Moisture is measured extremely accurately, and the measurement value of the neutron moisture meter is used to calibrate differences in indicated values due to changes in the properties of the object to be measured, which is the weak point of infrared moisture meters, making the measured values even more accurate. It will be shown.

Next, the operation of the apparatus of the present invention will be explained with reference to FIG. Coke 3 is conveyed by a belt conveyor 4 and charged into a coke hopper 1. After weighing the coke, it is sent to the blast furnace through the lower gate. When the coke 3 is discharged, the next coke 3 is charged into the coke hopper 1, and the operation is repeated continuously. The moisture content of the coke 3 conveyed to the coke hopper 1 is continuously measured using an infrared moisture meter 7. Let this measured value be M _R (t). During this measurement, a part of the coke 3 being conveyed is taken into the sampling hopper 6 using the sampling belt 5 at regular intervals, and the water content of the coke 3 is measured with the neutron moisture meter 2 attached to the sampling hopper 6. . Let this measured value be M _N.

Note that when the moisture measurement in the sampling hopper 6 is completed, the coke 3 is returned to the coke hopper 1 via another transport route (this route is omitted in the figure). The time taken for the coke 3 to reach the sampling hopper 6 measured by the infrared moisture meter 7 is defined as T _sec . sampling hopper 6
When the moisture measurement is completed, the value M _R (t-T) of the infrared moisture meter 7 before T _sec is compared with the measured value M _N of the neutron moisture meter. Since the value of the infrared moisture meter 7 measures the moisture in the surface layer on the belt conveyor 4 and does not take into account the influence of the particle size of the coke 3, the calculation unit 8 calculates the T _sec at the end of the moisture measurement in the sampling hopper 6. Infrared moisture meter value M _R
(t-T) and the value M _N of the neutron moisture meter, that is, ΔM = M _R (t-T) - M _N , the subsequent value M _R (t +
H+ΔT). To easily calculate the value, calculate the moisture content M′ _R (t) in coke 3 at the desired time.
is determined by M' _R (t) = M _R (t) - ΔM, but it is preferable to perform numerical processing using exponential smoothing, etc., taking into account the influence of noise.

(Effects of the present invention) As explained above, according to the apparatus of the present invention, an infrared moisture meter is disposed above the belt conveyor, and at the same time, the moisture content of the entire amount of coke charged into the coke hopper is measured. Regarding differences in measured values due to changes in the shape, particle size, color, etc. of the object to be measured, which is a weak point of infrared moisture meters, take out a portion of the coke and measure the moisture with a neutron moisture meter, and check the measured value of the infrared moisture meter. By calibrating the coke, it is possible to measure the moisture content in coke extremely accurately, and it is also possible to determine the coke moisture correction amount extremely accurately, which reduces the unit coke charge and has an extremely economical effect. It's large.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the coke moisture measuring device of the present invention, Figure 2 is a conventional coke moisture measuring device, and Figure 3 is an explanatory diagram of the coke moisture measuring device of the present invention.
The figure is a near-infrared absorption curve of water, and FIG. 4 is an explanatory diagram of an infrared moisture meter. 1... Coke hopper, 2... Neutron moisture meter, 3... Coke, 4... Belt conveyor, 5
... Sampling belt, 6 ... Sampling hopper, 7 ... Infrared moisture meter, 8 ... Computing unit, 1
0...Light-emitting lamp, 11...Condensing lens, 12...
... Optical filter, 13 ... Rotating plate, 14 ... Measured object, 15 ... Reflector, 16 ... Condensing mirror, 17
...Receiver, 18... Rotating motor, 19... Amplifier, 20... Synchronous detector, 21... Light emitting diode, 22... Light receiver, 23... Measurement signal holding circuit, 24, 25... Comparison signal Holding circuit, 26...
Average circuit, 27... Arithmetic unit.

Claims (1)

[Claims for Utility Model Registration] In an apparatus for measuring the moisture content of coke that is conveyed to the top of a hopper by a belt conveyor and charged into the hopper: an infrared moisture meter disposed on the belt conveyor that extends to the top of the hopper; and; a sampling conveyor for automatic sample collection, which is provided below the coke discharge end of the belt conveyor and above the hopper charging inlet so as to be able to move forward and backward; and; discharge of the sample taken by the sampling conveyor. a sampling hopper located below the end and equipped with a neutron moisture meter; and synchronizing the neutron moisture meter and the infrared moisture meter, and converting the measured value of the infrared moisture meter into the measured value of the neutron moisture meter. An apparatus for measuring the moisture content of coke charged into a hopper, comprising: a calculation device for calibration; and;