JP4129703B2 - Dedusting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dedusting device for a gas having a pressure containing dust, and more particularly to a dust removing device suitable for smoothly discharging separated dust and preventing clogging at a dust outlet.
[0002]
[Prior art]
In the case of a conventional dust removing device, for example, as shown in Japanese Patent Application Laid-Open No. 4-193364 (Japanese Patent Application No. Hei 2-321324) , dust collected by the dust removing device is blown down with the blow-down gas. A method of extracting from the dust outlet located at the bottom to the outside is used. However, when the dedusting device is used as a gas supply source for driving a gas turbine or the like with the gas cleaned by the dedusting device, a part of the gas supplied to the gas turbine is diverted as the blowdown gas. Therefore, the flow rate at the gas turbine inlet is reduced, and therefore it is required to reduce the blowdown gas as much as possible.
[0003]
In such a case, using the fact that the pressure of the blowdown gas is higher than that of the gas at the outlet of the dust removal device, the dust removal device is cleaned after the blowdown gas is cleaned by another dust removal device installed separately. The method of collecting at the outlet is taken. In this method, since the blowdown gas contains a lot of dust, it is necessary to reduce this dust as much as possible. Therefore, the outlet of the blowdown gas from the dust removing device container is more than the dust outlet of the dust separation mechanism inside the container. Install as high as possible, make the flow direction of the blowdown gas in the container upward, and let the dust fall to the dust outlet at the bottom of the container by gravity.
[0004]
[Problems to be solved by the invention]
In the case of the dust removing device configured as described above, the dust collected by the dust removing device is discharged from the dust outlet by the gravity acting on the dust separately from the blowdown gas. However, when the particle size of the dust is very fine, such as several microns, the falling speed of the dust is very slow, about several cm / s. In addition, since such fine dust has strong adhesion, it accumulates in the vicinity of the dust outlet of the dust removing device, and is likely to adhere to the dust outlet. When the dust outlet is closed, the dust collected by the dust removing device cannot be discharged, so that the performance of the dust removing device is lowered and the reliability of the downstream equipment is reduced.
[0005]
Accordingly, an object of the present invention is to provide a dust removing apparatus configured so that the dust is discharged by its own weight as described above. An object of the present invention is to provide a dust removing device that maintains stable discharge and does not cause a drop in dust removal performance.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a dust removing apparatus of the present invention comprises a cylindrical container whose lower part tapers downward, and a cyclone dust separating apparatus installed at the center of the container, and the container is a top part. A gas inlet for introducing gas containing dust into the top, a gas outlet for discharging the clean gas purified by the cyclone dust separator at the top, and a dust that is separated by the cyclone dust separator and falls by gravity at the bottom A lock hopper that has a dust outlet for discharging gas, and that is connected to the bottom of the dust outlet, a first on-off valve and a second on-off valve provided on the entry side and the exit side of the lock hopper, and release the internal pressure of the lock hopper In particular, a thermometer for detecting the temperature of the dust outlet and a first on-off valve in a state in which the second on-off valve is closed based on the measured value of the thermometer. Close and open third open / close valve Opening the inner pressure of the lock hopper Te, after closing the third on-off valve, characterized in that a control device for controlling to open the first on-off valve.
[0011]
In the dust removing apparatus of the present invention, dust collected in a high pressure state is usually temporarily stored in the lock hopper from the dust removing apparatus, and when the lock hopper is filled with dust, the first dust at the lock hopper inlet is temporarily stored. After the on-off valve is closed and the inside of the lock hopper is brought to atmospheric pressure by the third on-off valve, the second on-off valve at the outlet of the lock hopper is opened and discharged to, for example, a dust processing device downstream. By the way, when the discharge of dust deteriorates, the amount of dust passing through the dust outlet decreases, so the amount of heat supplied to the dust outlet decreases and the temperature of this part decreases. Can be detected. Therefore, if an abnormality (exit clogging due to dust) is detected by the thermometer at the dust outlet, the first on-off valve at the inlet is closed with the second on-off valve at the outlet closed, and the third on-off valve is opened. After releasing the internal pressure of the lock hopper and closing the third on-off valve, the first on-off valve at the inlet is opened in a short time and a differential pressure is generated instantaneously at the dust outlet. It is possible to promote the discharge of dust by the flow of gas.
[0012]
Further, instead of the thermometer and the control device in the dust removing apparatus of the present invention , the differential pressure gauge that detects the pressure difference between the inlet side and the outlet side of the dust outlet, and the second open / close based on the measured value of the differential pressure gauge A control device that controls to close the first on-off valve with the valve closed, open the third on-off valve to release the internal pressure of the lock hopper, and then close the third on-off valve and then open the first on-off valve May be provided . That is, in the case of abnormal discharge of dust, the differential pressure changes as compared with the case where dust is discharged smoothly, so that the abnormal discharge of dust can also be detected by this change in differential pressure. This is useful when the temperature of the dust is close to room temperature and the dust discharge abnormality is difficult to detect due to the temperature.
[0015]
More monitoring means dust discharge status of the dust outlet (thermometer, a differential pressure gauge, etc.) and promoting means for discharging dust (such as a valve operation b Kkuhoppa), characteristics of the dust to be used, due to construction of the dust processor By combining them appropriately, it is possible to provide a dust removing device that can ensure stable discharge of dust.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
<Embodiment 1>
A dust removing apparatus according to each embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, and 4.
As shown in FIG. 1, the dust removing apparatus 1 according to the first embodiment has, as main elements, generally a cylindrical shape in the upper part and a conical shape in which the lower part tapers downward, and a gas inlet 2a at the top and a gas outlet 2b at the top. A container 2, a centrifugal separator 3 installed in the container 2 and connected to the gas inlet 2a via a conduit 2e, a plurality of high-pressure gas injection nozzles 4 installed above the dust outlet 2c at the bottom of the container 2, A lock hopper 5 installed under the container 2 and connected to the dust outlet 2c, a thermometer 6 for detecting the temperature of the dust outlet 2c, and a control device (not shown) of the dust removing device 1 are provided. The number of high-pressure gas injection nozzles 4 is appropriately determined according to the specifications of the dust removing device.
[0017]
Furthermore, in the upper part of the container 2, a horizontal partition 2 d that partitions the inside of the container 2 up and down in order to guide the gas purified by the centrifugal separator 3 to the gas inlet 2 a is provided. The high-pressure gas injection nozzle 4 is provided with a high-pressure gas control valve 7 for supplying / stopping high-pressure gas outside the container 2. The lock hopper 5 is provided with a lock hopper inlet valve 8 (open / close valve) at the upper inlet, a lock hopper outlet valve 9 at the lower outlet, and a lock hopper pressure-reducing valve 10 at the upper outer wall of the hopper 8.
[0018]
In the dust removing apparatus 1 of the embodiment, a gas having a pressure including dust is introduced from a gas inlet 2 a at the top of the container 2. The container 2 is provided with a mechanism for separating dust in the gas, for example, a centrifugal separator (cyclone) 3 . And the clean gas from which dust was removed is discharged | emitted from the gas exit 2b. On the other hand, the dust separated from the gas falls downward in the container 2 and is discharged out of the container 2 from the dust outlet 2c. In the case of this embodiment, since the gas containing dust has pressure, the dust discharged from the container 2 is accumulated in the lock hopper 5 connected to the dust outlet 2c. When the lock hopper 5 is full, the lock hopper inlet valve 8 is closed, then the lock hopper pressure-reducing valve 10 is opened, the inside of the lock hopper 5 is brought to atmospheric pressure, the lock hopper outlet valve 9 is opened, and the dust inside the lock hopper 5 is opened. Is discharged to a downstream processing device or the like.
[0019]
In the case of such a dedusting device, the discharge from the dust outlet 2c is due to the gravity acting on the dust, so the discharge speed is very slow and the adherence is strong in the case of fine particles with a small particle size, etc. It becomes easy for dust blockage to occur near the dust outlet 2c.
[0020]
Therefore, in the present invention, the high pressure gas injection nozzle 4 and the high pressure gas control valve 7 are installed as means for promoting the discharge of the thermometer 6 and dust at the dust outlet 2c for the purpose of detecting and preventing it. . In this case, when the dust is normally discharged from the dust outlet 2c, the thermometer 6 shows a certain stable and almost constant temperature. However, if the dust discharge is not normal due to dust adhesion or accumulation near the dust outlet 2c, the amount of heat supplied by the dust will decrease, and the thermometer 6 will show a low value. Abnormality can be detected. When an abnormal discharge of dust is detected in this way, the high-pressure gas control valve 7 is opened, and the high-pressure gas flows downward from the high-pressure gas injection nozzle 4 installed on the upper side of the dust outlet 2c along the inner wall surface near the outlet 2c. It is possible to promote dust discharge by injecting. If this high-pressure gas injection is carried out at normal time intervals with a constant injection time, the high-pressure gas control is performed so that the time interval is shortened or the injection time is lengthened when an abnormality is detected. By controlling the valve 7, the discharge of dust can be promoted.
[0021]
Further, when a lock hopper is used as in this dust device, when an abnormal discharge of dust is detected, the lock hopper inlet valve 8 is once closed, and the lock hopper pressure reducing valve 10 is used to decompress the inside of the lock hopper 5. Then, after closing the lock hopper pressure-reducing valve 10, the lock hopper inlet valve 8 is opened, and the gas flow from the dust outlet 2c to the inside of the lock hopper 5 is instantaneously generated, thereby promoting the discharge of dust. Is possible. In addition, when a temporary increase in the amount of dust occurs as a precursor to the abnormal discharge of the dust, the thermometer 6 shows a higher temperature than usual, so by detecting this, Increase can be detected. Even in that case, it is possible to prevent the dust discharge abnormality in advance by operating the valve provided in the high-pressure gas injection nozzle 4 or the lock hopper 5 described above.
[0022]
<Embodiment 2>
A dust removing apparatus 1 according to Embodiment 2 of the present invention is shown in FIG. The dust removing apparatus according to the second embodiment detects a pressure difference between the inlet side and the outlet side of the dust outlet 2c and monitors the discharge state of the dust instead of the temperature detection in the first embodiment. A differential pressure gauge 12 is used. Also in this case, it is possible to detect an abnormality in dust discharge by detecting a change that occurs during an abnormality as compared with the normal value indicated by the differential pressure gauge 12. In addition, when the differential pressure gauge 12 is provided before and after the dust outlet 2c as in this dust removing device, the behavior of the differential pressure gauge during the pressure reduction operation of the lock hopper described in the embodiment of FIG. It is possible to detect the blockage situation. In other words, when the lock hopper inlet valve 8 is suddenly opened after the lock hopper 5 is depressurized, the differential pressure gauge instruction instantaneously returns to the instruction value before depressurization in the absence of blockage. Therefore, it takes a certain time to restore the indicated value, and it is possible to detect the blockage state by the behavior of the differential pressure gauge when the lock hopper is depressurized.
[0023]
<Third Embodiment> A third embodiment of the present invention will be described with reference to FIG. The dust removal apparatus of Embodiment 3 is an example suitable for a case where the temperature is very high, such as boiler exhaust gas. In this case, since the temperature of the dust collected by the dust removing device 1 is very high, a water-cooled screw feeder 13 for cooling the dust is installed at the dust outlet 2c. In this embodiment, a screw feeder 13 is provided on the exit side of the dust outlet 2c in addition to the dust removing apparatus of the first embodiment. However, the screw feeder 13 may also cause dust blockage. Therefore, in Embodiment 3, the piping 17 and the valve 16 that connect the outlet portion of the screw feeder 13 to a portion (atmospheric pressure) having a lower pressure than the dust outlet portion 2c are installed. In this embodiment, when a dust discharge abnormality is detected by the thermometer 6 , the valve 16 is opened for a short time in addition to the dust discharge promotion operation by the high pressure gas injection and the lock hopper decompression operation described above. This also makes it possible to generate a gas flow that promotes the discharge of dust at the dust outlet 4.
[0024]
In the third embodiment, a high-pressure gas buffer tank 14 and a pressure adjusting valve 15 for the buffer tank 14 are installed upstream of the high-pressure gas control valve 7. When an abnormal discharge of dust is detected, not only simply increasing the injection frequency or injection time of the high-pressure gas, but also by setting the pressure of the buffer tank 14 high by the pressure adjustment valve 15 and increasing the injection pressure of the high-pressure gas It becomes possible to promote the discharge of dust more effectively.
[0025]
<Embodiment 4> Embodiment 4 of the present invention will be described with reference to FIG. FIG. 4 shows a power generation turbine plant in which exhaust gas discharged from a boiler is cleaned by a dust removing device, and the gas turbine 22 is driven by the cleaning gas to generate electric power. The dust removing apparatus of Embodiment 4 is applied to this plant. In the case of such a plant, the amount of dust contained in the gas flowing into the dedusting device often changes similarly in response to the change when the operation state of the plant changes. When the dedusting device of the present invention is used in such a plant, in order to detect a temporary increase in the amount of dust that leads to blockage of the dust outlet 2c, a flow meter 18, A pressure gauge 19 and a thermometer 20 are installed, a differential pressure gauge 21 for measuring a differential pressure between the gas inlet 2a and the gas outlet 2b is installed, and an output meter of a generator 23 driven by the gas turbine 22 is installed, And when a change is recognized in the operation state of the plant from the value obtained by each measuring instrument, it is possible to prevent the dust outlet from being blocked by taking the above-described means for promoting the discharge of each dust. .
[0026]
【The invention's effect】
According to the present invention, since the dust device is configured to detect an abnormality (dust blockage) by a change in temperature or pressure at the dust outlet and to inject high pressure gas from the nozzle, the particle size of the dust is small. Also, stable discharge can be performed even with highly adherent dust. Also, instead of the temperature or pressure at the dust outlet, measure the temperature at the gas inlet of the dust device, predict abnormalities based on this temperature change, and inject high-pressure gas from the nozzle to maintain stable discharge. It can also be made.
[0027]
In addition, when the dust device is equipped with a lock hopper, an abnormality (dust blockage) is detected by a change in temperature or pressure at the dust outlet, and the internal pressures of the open / close valves and the lock hopper at the lock hopper inlet and outlet are detected. By operating the opening / closing valve to open and generating an air flow at the dust outlet, the dust at the dust outlet can be discharged, and stable discharge can be performed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a dust device according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a dust device according to a second embodiment of the present invention.
FIG. 3 is a configuration diagram of a dust device according to a third embodiment of the present invention.
FIG. 4 is a diagram showing a power generation turbine plant including a dust device according to a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Deduster 2 Container 2a Gas inlet 2b Gas outlet 2c Dust outlet 2d Horizontal partition 2e Conduit 3 Centrifugal separator 4 High pressure gas injection nozzle 5 Lock hopper 6 Thermometer 7 High pressure gas control valve 8 Lock hopper inlet valve 9 Lock hopper outlet valve DESCRIPTION OF SYMBOLS 10 Lock hopper pressure-reduction valve 12 Differential pressure gauge 13 Screw feeder 14 Buffer tank 15 Pressure adjustment valve 16 Valve 17 Piping 18 Exhaust gas 19 Pressure gauge 20 Thermometer 21 Differential pressure gauge 22 Gas turbine 23 Generator

Claims (2)

A cylindrical container having a lower portion tapering downward, and a cyclone dust separation device installed at the center of the container, and the container has a gas inlet for introducing a gas having a pressure containing dust at the top. A gas outlet through which the clean gas purified by the cyclone dust separator flows out at the top, and a dust outlet through which the dust separated by the cyclone dust separator and falling down by gravity is discharged at the bottom, and the dust outlet Dust removal comprising a lock hopper connected below, a first on-off valve and a second on-off valve provided on the entry side and the exit side of the lock hopper, and a third on-off valve for releasing the internal pressure of the lock hopper In the device
Based on a thermometer that detects the temperature of the dust outlet, and a measured value of the thermometer, the first on-off valve is closed while the second on-off valve is closed, and the third on-off valve is opened. A dust removing device, comprising: a control device that controls to open the first on-off valve after releasing the internal pressure of the lock hopper and closing the third on-off valve. Instead of the thermometer and the control device, a differential pressure gauge that detects the pressure difference between the inlet side and the outlet side of the dust outlet, and a state in which the second on-off valve is closed based on the measured value of the differential pressure gauge And a control device for controlling to open the first on-off valve after closing the first on-off valve, opening the third on-off valve to release the internal pressure of the lock hopper, and closing the third on-off valve. The dust removing apparatus according to claim 1 , wherein the dust removing apparatus is provided.

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