JP2587472B2 - Method and apparatus for controlling cooling water amount during production of granulated slag - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for controlling the amount of cooling water during the production of granulated slag.

[Conventional technology]

In order to improve the quality of water granulation, it is necessary to constantly grasp the amount of slag and control the amount of cooling water according to the fluctuating amount of slag.

As a means for measuring the amount of slag, a method of directly measuring the amount of molten slag, a method of measuring the load of a continuous dewatering device and calculating the amount, and attaching a load cell to a conveyor for transporting granulated slag after dehydration and measuring. Various methods have been proposed.

For example, in Japanese Patent Application Laid-Open No. 56-26752, a dehydrator is provided with a weight measuring device for measuring the weight of granulated particles, and a carry-out conveyor is provided with a flow measuring device for measuring the flow rate of granulated particles. The flow rate of the slag flowing out is calculated.

The cooling water amount control device at the time of manufacturing granulated slag is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-270238. As a device for suitably implementing this method, each blow box is divided into a plurality of pieces, and each is separately adjusted. A cooling water flow control device equipped with a valve is introduced.

This means that the nozzle plate provided in each blow box is divided into a plurality of parts, a water flow control valve is provided in each divided part, and the total opening area of the injection holes provided in all divided parts is always kept constant. As a result, the pressure of the cooling water pump and the total amount of supplied water are always maintained at constant values, so that the operation of the cooling water pump is stabilized, and each control valve is opened or closed according to the amount of molten blast furnace slag. In this way, the amount of water supplied to each blow box was maintained at an appropriate distribution ratio.

[Problems to be solved by the invention]

Regarding the cooling water amount control method, in the prior art,
The amount of granulated slag is affected by the water content, and as a result, there are no technical means that are still industrially used due to poor measurement accuracy, etc., and therefore, appropriate cooling according to the fluctuating slag amount At present, there is no method for controlling the amount of water.

Regarding the cooling water amount control device, see Japanese Patent Laid-Open No.
No. 38 had the following problems. That is, the distribution ratio of the supply amount of cooling water corresponding to the change in the amount of molten blast furnace slag changes.

Since the injection holes provided in each nozzle plate are worn, the amount of water and the water pressure fluctuate accordingly.

Due to the above factors, the granulation and cooling conditions of the granulated slag change, and the product quality changes.

The multi-stage blow box makes the equipment bulky, and is inferior in economics and maintainability.

Since the distribution ratio of slag and water becomes more than necessary, the production cost increases.

The present invention has been proposed in order to solve the above-described problems, accurately determine the amount of granulated slag without being affected by the water content, by grasping the amount of granulated slag,
Cooling water amount control method that enables finer control,
In addition, even if the amount of slag fluctuates, the distribution ratio of slag and cooling water and the blowing pressure are controlled so as to be constant in response to the change, and the cooling water amount control of granulated slag to stabilize product quality It is an object to provide a device.

[Means for solving the problem]

The present invention is applied to a method and a control device for controlling the amount of cooling water when producing granulated slag by spraying cooling water onto a slag to form granulated slag slurry and dewatering the slurry in a gravity dewatering tank to produce granulated slag. The technical measures were taken. That is, according to the method of the present invention, if the weight and volume of the granulated slag are measured and calculated in a dewatering tank in a slurry state, the granulated slag amount can be accurately measured without being affected by the water content. Based on the knowledge, the dewatering tank is provided with a weight measuring device that measures the weight of the granulated slag slurry in the dewatering tank, and a volume measuring device that measures the volume of the granulated slag slurry is provided.Based on these measured values, In this method, the amount of slag flowing into the dewatering tank is obtained by the following equation, and the amount of cooling water and the cooling water injection pressure for the slag are controlled according to the amount of slag.

W _S = γ _S (W−γ _W V) / (γ _S −γ _W ) where W _S : Weight of granulated slag W: Weight of granulated slag slurry in dewatering tank V: Granulated in dewatering tank Volume of slag slurry γ _S : Specific gravity of granulated slag γ _W : Specific gravity of water in the dewatering tank.

The apparatus of the present invention is a computing device that computes a cooling water flow rate such that a distribution ratio of slag and cooling water and a blowing pressure are set to predetermined values in accordance with a fluctuating amount of slag, and an output signal of the computing device. The cooling water flow meter is provided with a control device for controlling the cooling water flow control valve and the blowing pressure control device based on the signal of the blowing pressure gauge, respectively. A valve body, a nozzle plate provided with an ejection hole fitted to the control valve body, and a control valve body drive device for adjusting the gap between the control valve body and the ejection hole to adjust the blowing pressure.

[Action]

(1) In the method of the present invention, from the weight W of the granulated slag slurry in the dewatering tank, the volume V of the granulated slag slurry in the dewatering tank, the specific gravity γ _{S of} the granulated slag, and the specific gravity γ _W of the water in the dewatering tank The reason why the weight W _S of the granulated slag is required will be described below. The weight W of the granulated slag slurry in the dewatering tank is represented by the sum of the weight W _{S of the} granulated slag and the weight W _{W of the} water. That is, here _W = W W + W _S, because represented by _{W W = γ W (V-} W S / γ S), W = γ W (V-W S / γ S) + W S = γ W V- _{γ W W S / γ S +} W S _{Therefore, W S -γ W W S /} γ S = W-γ W V W S (1-γ W / γ S) = W-γ W V W S = γ S ( _{W-γ W V) / (} γ S -γ W) that is, the weight W _S of granulated slag is obtained.

Since the control of finer cooling water by weight W _S of the water granulated slag becomes possible, it is possible to improve the quality of the water-granulated.

(2) The operation of the device of the present invention will be described. The amount of slag (slag speed) varies in the range of 1 to 10 ton / min.
The distribution ratio between the cooling water and the slag needs to be 4 to 10 in view of production cost and safety measures. Since the present invention is configured as described above, it is possible to control the flow rate control valve of the cooling water and the control valve element of the blowing pressure control device immediately in response to the change in the amount of slag, And the distribution ratio of the cooling water and the blowing pressure can be kept constant. In addition, there is no fluctuation in the amount and pressure of the cooling water due to wear of the control valve body and the ejection hole.

Therefore, it is possible to stabilize the product quality and reduce the operation cost of the cooling water pump.

〔Example〕

FIG. 1 shows a system diagram of a cooling water amount control device and a cooling water system at the time of producing granulated slag of the present invention. FIG. 2 is an explanatory view of an embodiment of the pressure adjusting device of the present invention, and FIG. 3 is a sectional view taken along the line AA of FIG.

As shown in FIG. 1, pressurized water is injected into the slag flowing into the blowing box to form granulated slag slurry, and the granulated slag slurry is conveyed from the stirring tank 13 to the dewatering tank 20 by the granulation pump 14. You. This dewatering tank 20 has a dewatering screen 24 at the bottom of the tank.
So-called heavy dewatering is performed in which the granulated slag is settled and dewatered by utilizing the filtering action of the granulated slag. The water flowing out of the overflow pipe 16 or the dewatering pipe 15 is stored in a hot water tank 17, and after removing fine slag contained in the water, the water is sent to a cooling tower 18 by a pump, and cooled in the cooling tower 18 to be cooled. 19 are stored. This water is supplied to the cooling water pipe 6 by the cooling water pump 7 and is circulated and used again as pressure water.

FIG. 1 shows a state in which the granulated slag 23 in the granulated slag slurry is settled below the dewatering tank 20. The weight W of the granulated slag slurry in the dewatering tank 20 can be measured by a load cell 22 provided in the dewatering tank 20. At this time, by injecting water into the dewatering tank 20 in advance, the load cell 22 can be calibrated with high accuracy.
The measurement by 22 can be performed accurately. Further, the volume V of the granulated slag slurry can be accurately measured by a water level gauge 21 provided in the dewatering tank 20.

Since the specific gravity γ _S of the granulated slag is in water, it is close to the true specific gravity, and the specific gravity γ _W of the water in the dewatering tank can be easily obtained by measuring the temperature.

If over time weighed W _S of granulated slag production and production rate of the water granulated slag (tapping speed ton / min) it is also easily obtained. It is possible to control the amount of cooling water by the weight W _S of the water granulated slag.

As shown in FIG. 1, the control device of the present invention includes a flow meter 2 in a cooling water pipe 6 to which cooling water is supplied from a cooling water pump 7.
And a flow control valve 3, and the blow box is provided with a pressure gauge 4 and a pressure control valve body 5, respectively. Further, the arithmetic unit 11 calculates the flow rate of the cooling water such that the distribution ratio of the slag and the cooling water becomes a predetermined set value according to the fluctuating amount of slag. The controller 12 uses the result of the calculation and signals from the cooling water flow meter 2 and the blowing pressure gauge 4 to control the flow regulating valve 3 and the pressure regulating device 1.
Is controlled.

In the present apparatus, the change in the amount of slag is input by the calculation result of the arithmetic unit 11, but it is also possible to automatically detect and input the amount of molten slag, the change in the water temperature of the stirring tank, and the like. In practice, it is acceptable to input the eye measurement results.

As shown in FIG. 2, the pressure regulating device 1 drives two sets of wedge-shaped regulating valve bodies 5, a nozzle plate 10 provided with ejection holes 9 fitted to the regulating valve bodies 5, and the regulating valve body 5. It comprises a regulating valve drive 8 for adjusting the blowing pressure. The control valve drive 8 is controlled by the control device 12 shown in FIG. 1 to control the blowing pressure.

FIG. 4 is a graph showing the results of the implementation of the present invention. This shows the relationship between the slag time and the water supply amount when three cooling water pumps 7 are used and the operation is performed with the distribution ratio set to 5. In the conventional example, since the amount of slag could not be accurately grasped, the amount of water supply was increased promptly for safety. In the present invention, since the amount of water supply can be increased immediately before the distribution ratio becomes 5 or less, the amount of water used can be reduced and the power cost can be reduced. In addition, the number of nozzles of the blow box need not be multi-stage, and the size of the equipment can be reduced with only one stage.

〔The invention's effect〕

 The present invention has the following extremely excellent effects.

It is possible to significantly improve the control of the amount of slag in the metallurgical furnace and the control technology of the metallurgical furnace, which can contribute to an improvement in productivity.

Since the distribution ratio of the cooling water and the blowing pressure can be kept constant according to the amount of the molten slag, the product quality can be stabilized and the power cost can be reduced.

Since the distribution ratio of the cooling water and the blowing pressure can be arbitrarily set, granulated slags having different properties can be easily produced.

The size of the equipment can be reduced by using one nozzle for the blow box.

[Brief description of the drawings]

FIG. 1 is a system diagram of a cooling water amount control device and cooling water of the present invention, FIG. 2 is an explanatory diagram of an embodiment of a pressure adjusting device of the present invention, FIG. 3 is a cross-sectional view taken along line AA of FIG. FIG. 4 is a graph showing the results of the implementation of the present invention. DESCRIPTION OF SYMBOLS 1 ... Pressure adjustment device 2 ... Flow meter 3 ... Flow control valve 4 ... Pressure gauge 5 ... Control valve body 6 ... Cooling water piping 7 ... Pump 8 ... Control valve body driving machine 9 ... Injection hole 10 ... Nozzle plate 11 ... Calculation device 12 ... Control device 20 ... Dehydration tank 21 ... Water level gauge 22 ... Load cell 23 ... Granulated slag 24 ... Dehydration screen

Continued on the front page (72) Inventor Masahiro Hashimoto 1-chome, Kawasaki-dori, Mizushima, Kurashiki-shi, Okayama Pref.

Claims (2)

(57) [Claims] 1. A method for producing granulated slag by injecting cooling water into a slag to form granulated slag slurry and dewatering the slurry in a gravity dewatering tank to produce granulated slag. Provide a weight measuring device to measure the weight of the slag slurry and provide a volume measuring device to measure the volume of the granulated slag slurry, based on these measured values, determine the amount of slag flowing into the dewatering tank by the following equation, A method for controlling the amount of cooling water, wherein the amount of cooling water and the cooling water injection pressure for the slag are controlled according to the amount of slag. W _S = γ _S (W−γ _W V) / (γ _S −γ _W ) where W _S : Weight of granulated slag W: Weight of granulated slag slurry in dewatering tank V: Granulated in dewatering tank Volume of slag slurry γ _S : Specific gravity of granulated slag γ _W : Specific gravity of water in the dewatering tank. 2. An arithmetic unit for calculating a cooling water flow rate such that a distribution ratio of slag and cooling water and a blowing pressure are set to predetermined values in accordance with a fluctuating amount of slag, and an output signal of the arithmetic unit. A cooling water flow meter signal and a blowing pressure gauge signal are used to control a cooling water flow regulating valve and a blowing pressure adjusting device, respectively.The blowing pressure adjusting device has a plurality of wedge-shaped A control valve body, a nozzle plate provided with an ejection hole to be fitted to the control valve body, and a control valve body drive device for adjusting a gap between the control valve body and the ejection hole to adjust blowing pressure. Cooling water amount control device.