JPH04286512A - Method for controlling water spray for preventing splash of granular body heaped on raw material yard - Google Patents

Abstract

PURPOSE:To efficiently prevent dust from being caused by splash of granular bodies, which are heaped on a raw material yard. CONSTITUTION:At the time of preventing splash of particles 10 heaped on a raw material yard 11, moisture evaporation quantity of the heaped granular bodies 10 and amount of precipitation are measured continuously by an evaporation gauge 2 and a rain gauge 1 to obtain water spray quantity in response to the characteristic of the granular bodies 10, and the water is sprayed by a sprinkler nozzle 9 so that the granular bodies 10 includes moisture at a moisture content equal to or more than a splash limit.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to steel plants, thermal power plants,
The present invention relates to a method for preventing the scattering of powder particles such as iron ore, coal, etc. deposited in an outdoor raw material yard in a cement factory or the like.

0002

2. Description of the Related Art Generally, in steel mills and the like where powder and granular materials are stored outdoors, a method of preventing dust caused by scattering of the powder and granular materials is carried out by sprinkling water on piles. Methods for controlling watering at this time include a method of predicting the moisture content of powder from measured values of precipitation and solar energy as in JP-A No. 61-243707, and a method as described in JP-A-63-80869 and Wind direction, wind speed,
Dust scattering prevention is carried out by adjusting the moisture content of powder particles to match wind speed and direction conditions by controlling water spraying using meteorological data such as rainfall and dust sensors.

0003

[Problems to be Solved by the Invention] However, in the water sprinkling control method of the prior art, it is difficult to accurately calculate the moisture content of the surface layer of the powder from the amount of solar radiation, amount of rainfall, etc., and there are many errors. Furthermore, the method of controlling water sprinkling based on information captured by wind speed, wind direction, and dust sensors not only has many errors, but also has the problem of not being able to keep up with changes in the weather. An object of the present invention is to provide a technique for suppressing dust generation due to scattering of powder and granules by keeping the moisture content of the surface layer of accumulated powder and granules constant, which solves the above-mentioned problems. It is.

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for controlling water sprinkling to prevent scattering of powder and granules accumulated in a raw material yard, in which the amount of water evaporation of the accumulated powder and granules and the amount of rainfall are determined. is continuously measured, and based on the initial moisture content of the deposited powder and granular material and the saturated moisture content of the surface layer of the powder and granular material, the amount of water evaporation and the amount of rainfall change from moment to moment. Continuously calculate the moisture content of the surface layer of the powder and granule, calculate the amount of water to be sprayed from the calculated water content of the surface layer of the powder and the limit water content for powder and granule, and use the water nozzle based on the calculated water amount. This is a water sprinkling control method for preventing scattering of powder and granules deposited in a raw material yard, characterized in that water is sprinkled on the powder and granules deposited in a raw material yard so as to always maintain a surface water content of the powder and granules above the scattering limit.

[0005]

[Effect] The moisture content of the surface layer of the powder and granules deposited in the raw material yard is accurately predicted using an evaporometer and a rain gauge, and then the required watering amount is predicted, so the accurate moisture content can be estimated. Since the moisture content necessary and sufficient to prevent dust scattering can be maintained, dust scattering can be prevented regardless of changes in wind speed and direction. However, since the water retention capacity differs depending on the properties of the powder or granule, such as particle size, porosity, etc., detailed control can be achieved by creating an estimation formula for each powder or granule.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on drawings showing embodiments thereof. FIG. 1 is a perspective view schematically showing a raw material yard together with a control block of the method of the present invention. In FIG. 1, a raw material yard 11 is a raw material storage area with a necessary area divided, and generally there may be a plurality of these. many. In each raw material yard 11, various powder and granular raw materials 10 are placed in piles, and in order to prevent the generation of dust from the raw materials 10, a water nozzle 9 and a water tap 8 to control the water nozzle 9 are installed respectively. A series of pipes 13 are installed. Reference numeral 7 denotes a pump having the required capacity to ensure the amount of water to be sprinkled, and the operation of the pump 7 causes water in the water tank 12 to flow through the pipe 13 to the sprinkler nozzle 9.
water is sprinkled from The amount of water sprayed from the water spray nozzle 9 is controlled by the water spray control device 6.

The arithmetic and control system includes a comparison arithmetic section 5, a dust scattering prevention standard storage section 4, and a raw material property storage section 3. The arithmetic and control system uses a computer system consisting of a CPU, RAM, ROM, etc. The raw material property storage section 3 has a moisture content table, a yard map table, a moisture content characteristic table, etc., and can be updated with new data by connecting to a host computer. The dust scattering prevention reference section 4 has a scattering limit value table.

As external sensors, an evaporator 2 for measuring the amount of moisture evaporated from the raw material and a rain gauge 1 for measuring the amount of rain during rainfall are installed at strategic locations, and the amount of moisture evaporated from the raw material and the amount of rainfall are continuously measured. Load data automatically. The surface moisture content of the raw material 10 is determined by first measuring the moisture content immediately after unloading the raw material 10 in the raw material property storage unit 3.
At the same time, the location where the cargo was unloaded is also stored in the yard map table.

The evaporation characteristics experimentally determined in advance for each raw material 10 are schematically shown in FIG. 2, and are stored in the water content property table of the raw material property storage section 3 in the form of a numerical table. Figure 2
shows the relationship between the amount of evaporation and the water content reduction in the surface layer of the raw material,
a, b, and c come from the difference in raw materials. Further, FIG. 3 shows the wetting characteristics of the powder and granular material, and schematically shows the relationship between the amount of rainfall and the amount of increase in the moisture content of the raw material. This is stored in the moisture content characteristic table of the raw material property storage section 3 in the form of a numerical table.

FIG. 3 is, so to speak, the opposite of FIG. 2, and it is sufficient to determine the moisture content of each raw material experimentally from the amount of rainfall. In FIG. 3, a, b, and c represent differences due to the characteristics of the raw materials. The evaporation meters 2 depend on the location, such as shade and ventilation conditions, and the larger the material yard 11 is, the more this will affect the evaporation meters 2, so it is sufficient to install as many as necessary. Rain gauges also differ depending on location, so installing multiple rain gauges will improve accuracy. The data from the rain gauge 1 and the evaporation gauge 2 are calculated and updated from time to time by adding or subtracting data from the raw material property storage section 3.

On the other hand, the dust scattering prevention standard storage section 4 stores the limit moisture content obtained from the experimental results of the dust generation characteristics of each raw material in the form of a numerical table in the scattering limit value table of the storage section 4. I'll keep it. FIG. 4 schematically shows the relationship between the raw material surface moisture content and the amount of dust generated. From this relationship, the upper limit of the moisture content corresponding to the saturated moisture state of the surface layer of the powder and the lower limit of the moisture content corresponding to the completely dry state are determined. In other words, in Fig. 4, the moisture content corresponding to the allowable amount of dust generation Y1 - Y2 is the upper limit X.
2 and the lower limit is X1. The amount of water to be sprinkled for each raw material is determined by the comparison calculation unit 5 and the raw material property storage unit 3 and the dust scattering prevention standard storage unit 4.
For the raw material 10 whose moisture content has reached the lower limit, the required amount of water to be sprinkled is calculated from the upper limit moisture content minus the lower limit moisture content from FIG.

At this time, the actual water sprinkling amount (=watering time) is calculated from the evaporation amount, but this can be easily calculated as the water sprinkling amount by determining the surface area from the yard map table in the storage section 3. The amount of water sprinkled is further converted into time based on the relationship with the capacity of the pump 7, and the required watering locations and time are output to the water sprinkler control device 6. The output of the watering control device 6 starts and stops the pump 7 and opens and closes the watering faucet 8 of the watering nozzle 9 of the material storage area. This makes it possible to always maintain a constant moisture content for each raw material.

[0013]

Effects of the Invention As explained above, according to the present invention, the dust generation characteristics of the raw material powder are stored in advance as upper and lower limit values in relation to the moisture content, while changes in the moisture content are measured by evaporation that is close to the actual value. The amount of water to be sprinkled for each raw material can be determined by estimating it from the water meter and rain gauge. Therefore, even if the wind speed or direction changes suddenly, no dust is generated, there is no need to spray water too much or too little, and the device as a whole can be made simpler than in the prior art.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a raw material yard together with a control block according to the present invention.

FIG. 2 is a diagram showing the relationship between water evaporation (l) and surface water content loss (%).

FIG. 3 is a diagram showing the relationship between rainfall (mm/hr) and moisture content increase (%).

FIG. 4 is a diagram showing the relationship between surface moisture content (%) and dust generation amount (g).

[Explanation of symbols]

1 Rain gauge 2 Evaporation meter 3 Raw material property memory section 4 Dust scattering prevention standard storage unit 5 Comparison operation section 6. Watering control device 7 Pump 8 Water tap 9 Water nozzle 10 Raw materials (powder) 11 Raw material yard 12 Water tank 13 Piping

Claims (1)

[Claims] 1. In a method of controlling water sprinkling to prevent scattering of powder and granules accumulated in a raw material yard, the amount of water evaporation and rainfall of the accumulated powder and granules are continuously measured, and the initial Based on the moisture content and the saturated moisture content of the surface layer of the powder or granule, continuously calculating the moisture content of the surface layer of the powder or granule that changes from time to time from the measured values of the amount of water evaporation and the amount of rainfall,
The amount of water to be sprayed is calculated from the calculated water content in the surface layer of the powder and the water content at the scattering limit of the powder. A water sprinkling control method for preventing scattering of powder and granules accumulated in a raw material yard, characterized in that water is sprinkled so as to constantly maintain the moisture content of the surface layer of the powder and granules.