JPS6139245B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for preventing the scattering of coal dust in outdoor coal storage areas such as call centers and coal-fired power plants. Currently, energy resources are being diversified in Japan, and coal is being reconsidered as an alternative to oil, which has traditionally been the main energy source. Construction of new coal-fired power plants is planned. In all of these cases, it is necessary to store a huge amount of coal, and pollution of the surrounding environment due to scattered coal dust has been highlighted as one of the pollution problems such as noise, air pollution, and water pollution. For this reason, methods to prevent the scattering of coal dust such as indoor coal storage or silo coal storage are being considered, but since outdoor coal storage is the most advantageous in terms of equipment cost, this outdoor method is often adopted. There is a need for a method for preventing the scattering of coal dust. Conventionally, methods for preventing scattering of coal dust in an outdoor coal storage yard include rolling compaction using a bulldozer, spraying an agent to prevent scattering of coal dust, and pouring water to prevent scattering of coal dust. Although compaction using a bulldozer requires a lot of time and effort, it is less effective in preventing scattering under strong winds, and on the other hand, dispersing coal dust scattering preventive agents requires expensive coal dust scattering preventive agents and complicated piping systems. Particularly when loading and unloading coal in a short period of time, the frequency of spraying increases, which requires a lot of labor and a large amount of coal dust scattering prevention agent.Therefore, water injection to prevent coal dust scattering tends to be widely used. be. As shown in Figure 1, the wind speed at which coal dust begins to scatter changes depending on the particle size of the coal and the moisture attached to the coal. Domestic coal, which has been widely used in the past, generally has a large particle size and tends to be difficult to scatter. However, more than 20% of the overseas coal that we will have to rely on in the future is coal with small particle diameters of 1mmφ or less.
It tends to scatter very easily. However, as shown in Figure 1, these foreign coals will not scatter even in strong winds if a certain amount of attached moisture is added to them, but in strong winds, the attached moisture tends to evaporate due to the wind, and when the attached moisture decreases, it begins to scatter. Therefore, a water discharging device is required that can inject water as uniformly as possible over the entire coal pile even during strong winds. The conventional method for preventing scattering of coal dust is to set the water nozzle at a certain angle of elevation relative to the coal pile, and then rotate the water nozzle facing the coal pile to spray water only in the form of rain. Because the water flow is easily deflected by the wind and the distance the water reaches is limited, it is impossible to inject water into the entire coal pile and no effect can be expected to prevent coal dust from scattering, so another device was used. Water was being poured manually. The present invention was made to eliminate these drawbacks, and by controlling the operation of the water spraying device according to the wind speed in the outdoor coal storage area, water can be uniformly injected into the coal storage pile even under any wind speed, and the coal dust can be removed. A method for preventing scattering of coal dust in an outdoor coal storage yard is provided. The method for preventing scattering of coal dust of the present invention involves repeatedly rotating the water nozzle from a water spraying device placed around the coal pile in a fan shape relative to the coal pile, and spraying water directly onto the coal pile during weak winds. In this method, the elevation angle of the water discharge device on the windward side is sometimes increased to inject water scattered by the wind into the coal pile, thereby making the coal pile retain a uniform amount of moisture and preventing the scattering of coal dust. Then, at least one of the amount of moisture adhering to the coal on the surface of the coal pile and the wind speed value in the coal pile is measured, and when the value reaches a preset value, the operation and stop of the water spraying device is controlled based on that value and the wind direction. This is a method for preventing coal dust scattering by controlling the elevation angle of water spraying equipment. Next, the method for preventing scattering of coal dust of the present invention will be explained in detail. The method of the present invention will be explained with reference to the drawings. As shown in Figure 2, water spray devices are appropriately installed on the ground around the coal pile, and in the method of the present invention, a wind direction and speed meter (not shown) is installed inside the coal pile. Monitor the wind direction and speed in the coal storage area by installing it around the coal storage area or by sharing an attached anemometer that can measure almost the same value as the wind direction and speed within the coal storage area, and make sure that the wind speed does not fall below the preset value. During weak winds, the water nozzles of the water spray equipment installed around the coal storage area are maintained at a preset elevation angle relative to the ground surface.
Water is sprayed by rotating in a fan shape facing the coal pile, and water is sprayed directly onto the coal pile in the form of rain.When the wind speed is higher than a preset value, the preset elevation angle of the water spray nozzle of the water spray device on the windward side is adjusted. Water is injected into the coal pile using a tailwind, preferably by inverting and rotating water to form a water curtain that is substantially perpendicular to the ground surface and facing the coal pile. In this case, in the wind direction shown in FIG. 3, it is preferable to inject water according to a program set in advance for each wind direction as shown in Table 1, since effective water injection can be performed.

[Table] In other words, when the wind is weak, water is sprayed directly from water spray devices No. 1 to No. 12, and when the wind is strong, when the wind direction is as shown by A in Figure 3, No. 1 on the windward side,
The water spraying devices No. 2, No. 7, and No. 8 perform water injection using the above-mentioned scattered water. At this time, No.
3, No. 4, No. 9, and No. 10, which are located parallel to the wind direction, may have any water injection pattern, such as the above-mentioned direct water injection or splash water injection. Then, you may stop discharging water from No. 5, No. 6, No. 11, and No. 12 on the leeward side. It is also possible to simultaneously discharge water from all the necessary water discharging devices, but in this case, the amount of water discharged per unit time will be enormous, and the pressurized water supply device, piping equipment, etc. will have a large capacity. A method of sequentially discharging water by dividing it into individual units or multiple units is also adopted.In the sequential discharging method, even if the water discharging devices are placed in a fixed order, the water discharging devices placed on the windward side are moved sequentially to the leeward side. They may be selected in any order or in any appropriate manner, and are not specified in any way. Further, when the wind speed exceeds a preset value, the water injection pattern may be switched automatically based on the wind speed signal, or the water injection pattern may be switched manually. In addition, as shown in Figure 4, when this coal dust scattering prevention method is automatically implemented, the wind direction and wind speed in or around the coal storage yard measured by an anemometer and the attached moisture meter are measured. The amount of moisture adhering to the coal on the surface of the coal pile is converted into a signal by each converter and sent to the water discharge control panel for preventing coal dust scattering. , when the amount of moisture adhering to the coal on the surface of the coal pile has decreased to a preset amount of moisture, or the relationship between the wind speed at which coal dust starts scattering and the amount of adhering water as shown in Figure 1, the wind speed signal and the amount of adhering moisture at that time are determined. The possibility of coal dust scattering is determined from the signal using a preset program on the control panel, and when there is a risk of coal dust scattering, the control panel activates the pressurized water supply device that supplies pressurized water to the water spray device. According to the wind direction and wind speed at that time, the above-mentioned water spraying device is selected and the elevation angle of the water spraying device is set to spray water, and water is injected into the coal pile to prevent the scattering of coal dust.
Naturally, it is preferable to automatically measure the amount of adhered moisture and send the signal to the control panel, as it saves labor. You can find a way to give it to others. As explained above, the coal dust scattering prevention method of the present invention is as follows:
Since water can be effectively injected into the coal pile according to the wind speed, the moisture attached to the coal pile can be maintained at a value that makes it difficult to scatter throughout the coal pile, and the scattering of coal dust can be prevented regardless of the wind direction. In particular, with the conventional method, it is possible to inject water into the coal pile only during weak winds, and in order to improve the wind resistance with this method, it is necessary to dramatically increase the amount of water discharged per unit time, which requires pressurized water supply equipment. However, while it was necessary to install large-capacity piping equipment,
By adopting the method of changing the elevation angle of water discharge according to the wind speed, the present invention dramatically improves wind resistance performance with the same amount of water discharge per unit time as before. This invention can also prevent spontaneous combustion disasters, and the present invention greatly contributes to the development of industry.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between coal particle size, adhering moisture, and wind speed at which coal dust starts scattering.
The figure is an explanatory diagram showing the wind blowing in each direction in the arrangement shown in Fig. 2 and the device numbers to be sprayed with water, and Fig. 4 is an explanatory diagram when the present invention is automatically carried out.

Claims (1)

[Scope of Claims] 1 Water spraying equipment installed around the coal storage pile directly sprays water onto the coal storage pile during weak winds, and increases the water discharge angle of attack of the water injection equipment installed at least on the windward side during strong winds. A method for preventing scattering of coal dust, which is characterized by discharging water, scattering the water by wind pressure, and injecting the scattered water into a coal pile. 2. Measure at least one of the amount of moisture adhering to the coal on the surface of the coal pile and the wind speed in the coal pile, and when the value reaches a preset value, control the operation and stop of the water spray device based on that value and the wind direction. 2. The method for preventing scattering of coal dust according to claim 1, wherein the angle of attack of water discharged by a water discharge device that discharges water at the same time is controlled.