JPS6134071B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method and apparatus for treating molten slag generated in a blast furnace, converter, etc. This invention relates to a method and apparatus for treating molten slag in which the molten slag is cooled by using a cooling gas containing a mixture of the following and utilizing the endothermic reaction heat generated when water vapor in the cooling gas is converted into hydrogen gas.

[Prior Art] Conventional methods for processing molten slag include a water crushing method in which molten slag is granulated with a fountain, a wind crushing method in which molten slag is granulated with an air jet, and a dry pit method in which the molten slag is discharged into a dry pit and crushed after being solidified. be.

[Problems to be solved by the invention] However, in the case of the water fracking method, a large amount of water is required, the equipment is large and the equipment costs and running costs are high, and a large amount of water vapor mixed with dust is generated, causing pollution. There are also difficulties in countermeasures. Furthermore, even in the case of the wind crushing method, since crushing and cooling is performed using air, a large amount of compressed air is required, and measures against scattering of dust are required. Furthermore, in the case of the dry pit method, a large space is required for discharging and cooling the slag, and there are also problems such as the generation of yellow water due to the cooling water, which causes pollution problems.

Therefore, in order to solve these problems, the present inventor proposed a wind crushing method that uses a cooling gas in which a high carbon content is mixed into a gas containing CO ₂ . This method cools and solidifies molten slag by utilizing the heat absorption generated when CO ₂ is converted to CO through a chemical reaction between CO ₂ and C in the cooling gas, resulting in significantly lower cooling than the conventional wind crushing method. The amount of gas can be reduced. However, due to cost reasons, exhaust gas from a combustion furnace is used as a CO ₂ source, but the CO ₂ content in the exhaust gas is usually less than 20%, so reducing the amount of cooling gas is still not sufficient, and there is a need for a better method. is desired.

The present invention has been devised to effectively solve the above-mentioned conventional problems.The purpose of the present invention is to achieve high cooling efficiency, reduce the amount of cooling gas, and save resources.
An object of the present invention is to provide a method and apparatus for processing molten slag that can promote energy saving and compactness.

[Means for Solving the Problems] The molten slag processing method of the first invention mixes a gas containing water vapor and a high carbon content to form a cooling gas, and a jet of this cooling gas cools the molten slag. It is cooled and air-pulverized into fine particles.

Moreover, the molten slag processing apparatus of the second invention includes:
A steam generator supplying water vapor, a high carbon content feeder supplying a high carbon content material, and a jet of cooling gas containing a mixture of water vapor from the steam generator and high carbon content from the high carbon content feed device. A molten slag solidifying device is provided with a cooling plate having a generally U-shaped cross section and an annular shape for rotating and guiding the molten slag blown up by the molten slag.

[Operation] The cooling gas injected into the molten slag causes a chemical reaction due to heat input from the molten slag. In this chemical reaction, water vapor in the cooling gas is converted to hydrogen gas, which is accompanied by a large amount of heat absorption. Due to this heat absorption, the molten slag is rapidly cooled and solidified into fine particles.

[Example] Furthermore, the molten slag that is blown onto the cooling plate of the molten slag solidification device along with the jet of cooling gas is rotated along the cooling plate that has a U-shaped cross section. At this time, heat exchange occurs through effective contact between the molten slag and the cooling plate.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, 12 is a blast furnace;
A molten slag solidification device 9 for solidifying the molten slag 13 discharged from this, and a cooling tower 16 for cooling the solidified high temperature slag 14 from the solidification device 9 into solidified low temperature slag 15 are installed in series. A slug line is configured.

Further, in order to supply the cooling gas 5 to the molten slag solidification device 9, a steam extraction pipe 3 is provided between the steam drum 22 and the high carbon content supply device 8, and a steam extraction pipe 3 is provided between the high carbon content material supply device 8 and the solidification device. Cooling gas introduction pipes 39 are interposed between the cooling gas introduction pipes 9 and 9, and the extraction pipe 3 is provided with a pressure regulating valve 1 and a flow regulating valve 4 toward the supply device 8. The high carbon content supply device 8 mixes fine powder of a high carbon content material such as coke, charcoal, or coal into the hydrogen gas that has passed through the takeout pipe 3 to generate a cooling gas 5, which is then sent to the solidification device 9. supply. Furthermore, a fuel gas supply line is connected to the molten slag solidification device 9, which leads the fuel gas 10 drawn out from the device to the blast furnace 12 via a dust remover 11 and a blower 2.

Further, a circulation loop is formed between the cooling tower 16 and the waste heat boiler 20 to circulate air 17, 17a in order to cool the solidified high temperature slag 14 of the cooling tower 16 and recover its heat. A fan 18 and a dust remover 19 are provided in the loop. In addition, the waste heat boiler 20 has steam 21
A steam drum 22 is installed in series to circulate and heat the steam. Further, the waste heat boiler 20 is connected to a steam turbine 24 driven by superheated steam 21a supplied from the steam drum 22 and heated, and a generator 23 is connected to the steam turbine 24.

In addition, a condenser 26 is provided in order to return the steam used in the steam turbine 24 to water 25, and the water 25 from the condenser 26 is guided to the waste heat boiler 20 via a pump 27 to produce steam 21. The molten slag is introduced into a line and a molten slag solidifying device 9 to form high-temperature water 28,
A line that guides this high-temperature water 28 to the boiler 20 is configured.

FIG. 2 shows the molten slag solidification device 9, which includes a molten slag receiver 30 disposed below the outlet of the slag gutter 29 of the blast furnace 12, a crushing chamber 31 for crushing the molten slag 13, and a crushing chamber 31 for crushing the molten slag 13. Solidified high temperature slag 1
4, and a sealing device 33 that seals the lower part of the gate 32 from the atmosphere. The molten slag receiver 30 includes an outlet seal portion 35 extending downward from its lower part, and a stopper 34 that is vertically movable to seal the outlet seal portion 35 at the end of operation.
A plurality of slag outlet holes 36 are formed at the lower end of the outlet seal portion 35 to separate the molten slag 13 into a plurality of streams.

The crushing chamber 31 surrounds the outer periphery of a plurality of slag flows flowing down from the outlet seal part 35 and the slag outflow hole 36, has a lower end extending to an appropriate position within the crushing chamber 31, and leads out the fuel gas 10 to its upper end. A cylinder 38 is connected to a fuel gas take-off pipe 37. In addition, the side wall of the wind crushing chamber 31 is penetrated, and the wind crushing chamber 3
A cooling gas (air-crushed gas) introduction pipe 39 for blowing cooling gas 5 into the cylinder 38 is provided, and a cone 40 with a conical upper surface is provided below the lower end of the cylinder 38 to receive and guide the slag flow. Furthermore, a nozzle 41 is provided at the lower part of the cone 40 for blowing up the cooling gas 5 from the outer periphery toward the outer periphery of the cone 40.

In addition, on the upper part of the inner circumferential wall that partitions the blasting chamber 31,
A cooling plate 43 is provided in which a cooling pipe 42 for passing water 25 is disposed. Cooling plate 4
Reference numeral 3 denotes a cylindrical center plate 43a provided along the inner peripheral wall of the crushing chamber 31, and a flange-shaped upper plate 43 extending inward from the upper end of the center plate 43a.
b, and a lower plate 43c in the shape of a truncated conical cylinder whose diameter is gradually reduced downward from the lower end of the center plate 43a.

The seal device 33 includes a lower water seal ring 44 formed below the crushing chamber 31 to surround the gate;
A seal body 47 that performs a water seal by immersing the water seal ring 44 into the water 46 in the water reservoir 45;
The carriage 49 includes a cylinder 48 that is connected to the seal body 47 and moves the seal body 47 up and down. Note that the molten slag solidification device 9 is connected to each slag trough 2.
One cooling tower 16 and one waste heat boiler 20 are installed in total. It is also lined with fireproof material where necessary.

Next, the operation of this embodiment will be described.

The steam taken out from the steam drum 22 to the steam extraction pipe 3 is pressure regulated by the pressure regulating valve 1, and the pressure is regulated by the flow regulating valve 4.
After being metered in, fine coke etc. are mixed in the high carbon content supply device 8 to generate the cooling gas 5.
This cooling gas is ejected into the crushing chamber 31 from the nozzle 41 through the cooling gas introduction pipe 39.

On the other hand, the molten slag 13 discharged from the blast furnace 12 flows into the molten slag receiver 30 via the slag drain 29 . The molten slag 13 at a temperature of about 1500°C that has flowed into the molten slag receiver 30 is divided into a plurality of streams through the slag outlet hole 36 at the lower end of the outlet seal portion 35 (the contact area with the cooling gas 5 or fuel gas 10 rising inside the cylinder 38 is (in order to improve heat exchange), the water flows down onto the cone 40. During this time, the temperature of the molten slag 13 drops to about 1300°C.

The molten slag 13, which has become a conical cylinder-shaped flow along the upper surface of the cone 40, is crushed by the cooling gas 5 ejected from the nozzle 41 and blown up as it flows down from the outer peripheral edge of the cone 40. The molten slag 5 blown up by the jet of cooling gas 5 comes into contact with the lower surface of the upper plate 43b of the cooling plate 43, and the upper plate 4
3b, it flows down along the center plate 43a, and further slides down the lower plate 43c, where it is cooled and approximately
The solidified high-temperature slag 14 at 1000° C. becomes particles and accumulates in the lower part of the blasting chamber 31.

The cooling gas 5 ejected from the nozzle 41 is heated to high temperature by directly exchanging heat with the high-temperature molten slag 13 when the molten slag 13 is crushed and when it rises in the cylinder 38, and water vapor (H ₂ O) in the cooling gas is generated. is chemically changed to H ₂ according to the following formula, cooling gas 5 becomes fuel gas 1
0, the fuel gas is taken out from the fuel gas take-off pipe 37, dust removed by the dust remover 11, pressurized by the blower 2, and blown into the blast furnace 12.

C+H ₂ O→H ₂ +CO−28.8Kcal C+2H ₂ O→2H ₂ +CO ₂ −18.7Kcal Since the above reaction is a violent endothermic reaction, when simply using air as the cooling gas 5, use the sensible heat of the air. However, in this method, not only the sensible heat of the cooling gas 5 but also the reaction heat of a much larger endothermic reaction is used to cool the molten slag 1.
3, the cooling efficiency is high and rapid cooling can be achieved in a short period of time, and the amount of cooling gas used can be significantly reduced. Therefore, the cooling capacity is increased, and the operating cost can be reduced and the device can be made smaller. Furthermore, when a mixed gas of CO ₂ and C is used as a cooling gas, the CO ₂ source is usually combustion exhaust gas and the amount of CO ₂ in the exhaust gas is about 20%, so the above heat absorption effect is not sufficient. However, in the present invention, since water vapor is used, 100% water vapor can be obtained easily and inexpensively, so that a sufficient endothermic effect can be achieved.

In addition, since the molten slag 13 blown up by the jet of cooling gas 5 is reversed on the cooling plate 43 without turning, the contact area between the molten slag 13 and the cooling plate 43 is increased, so the cooling effect is high and the air crushes the slag. Room 3
1 can be made compact.

When an appropriate amount of solidified high-temperature slag 14 has accumulated in the crushing chamber 31, the cylinder 48 lowers the seal body 47 to horizontally move the cart 49, and then the gate 32
is opened and the solidified high temperature slag 14 is cut out onto a transport vehicle.
It is transported to the cooling tower 16. In the cooling tower 16, the solidified high temperature slag 14 is cooled by contacting with air 17 at about 150°C, and is discharged as solidified low temperature slag 15 at about 250°C.

On the other hand, due to heat exchange with the solidified high temperature slag 14,
The high-temperature air 17a, which has reached a temperature of about 800° C., is removed by a dust remover 19, enters a waste heat boiler 20, exchanges heat, and returns to the fan 18. The water 25 sent to the waste heat boiler 20 by the pump 27 is sent to the waste heat boiler 20.
The heated steam 21 is sent to the waste heat boiler 20 again via the steam drum 22, and becomes superheated steam 2.
The water becomes water 25 in the condenser 26 and returns to the pump 27. Further, a part of the water 25 discharged by the pump 27 is transferred to the cooling plate 4 of the molten slag solidification device 9.
The cooling plate 43 is cooled through the deterioration pipe 42 in the waste heat boiler 2, and the temperature is raised to become high-temperature water 28.
0 and becomes water vapor 21. In this way, the heat recovered when the molten slag 13 is cooled can be effectively used for power generation.

In the above embodiment, the gas (fuel gas 10) generated from the cooling gas 5 in the molten slag solidification device 9 is used as a reducing fuel in a combustion furnace such as the blast furnace 12. The fuel gas 10 can also be used simply as a reducing agent. Furthermore, the cooling gas 5 may not only contain 100% water vapor, but may also be a gas containing a large amount of water vapor.

[Effects of the Invention] In summary, according to the present invention, the following excellent effects can be achieved.

(1) Since the heat absorption during the chemical reaction between H ₂ O and C is utilized, the cooling effect is high, allowing rapid cooling and increasing the cooling capacity.

(2) Furthermore, since not only the sensible heat but also the reaction heat of endothermic reactions is utilized, the amount of cooling gas for cooling can be significantly reduced. Furthermore, when using the endothermic reaction between CO ₂ and C, the exhaust gas from a combustion furnace is usually used as the CO ₂ source, and the amount of CO ₂ in the exhaust gas is less than 20%, so the cooling effect of the endothermic reaction is sufficient. However, since the present invention uses water vapor, 100% or close to 100% water vapor can be obtained easily and inexpensively, so the endothermic reaction effect can be effectively exhibited, and the cooling gas is even more effective than when using _CO2 . The amount can be reduced. Therefore, the running cost of the device can be significantly reduced and the device can be made more compact.

(3) Since the cooling plate of the molten slag solidification device is formed with a substantially U-shaped cross section, the molten slag blown up by the cooling gas is guided to the cooling plate and rotated along the cooling plate. Therefore, the molten slag is effectively brought into contact with the cooling plate, and the cooling effect can be improved, and together with the above-mentioned reduction in the amount of cooling gas, the molten slag solidification apparatus can be downsized.

(4) Water vapor used as cooling gas can be converted into high-temperature fuel gas using inexpensive high-carbon materials such as fine coke, resulting in a large energy-saving effect.

(5) When the above fuel gas is blown into the blast furnace, CO and H ₂ in the gas act as reducing agents, so the amount of expensive coke used for blast furnace charging can be reduced.

(6) Since the amount of cooling gas is small, a closed system can be easily realized, and the dispersion of dust and water vapor into the atmosphere can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic system diagram showing an embodiment of a molten slag processing system including an apparatus according to the present invention, and FIG. 2 is an enlarged longitudinal sectional view of the molten slag solidification apparatus of FIG. 1. In the figure, 3 is a steam extraction pipe, 5 is a cooling gas, 8 is a high carbon content supply device, 9 is a molten slag solidification device,
12 is a blast furnace, 13 is a molten slag, 14 is a solidified high temperature slag, 15 is a solidified low temperature slag, 16 is a cooling tower,
21 is steam, 22 is a steam drum, 31 is a blowing chamber, 39 is a cooling gas introduction pipe, 41 is a nozzle, 43
is a cooling plate.

Claims (1)

[Claims] 1. A method of pulverizing molten slag using a jet of cooling gas, in which a gas containing water vapor and a high carbon content are mixed to form a cooling gas, and the water vapor and carbon in the cooling gas are mixed. A method for treating molten slag, characterized in that the molten slag is cooled and solidified by a jet of the cooling gas by utilizing the endothermic heat generated when water vapor is converted to hydrogen gas through a chemical reaction. 2 A steam generator that supplies water vapor, a high carbon content supply device that supplies a high carbon content material, and a mixture of the steam from the steam generator and the high carbon content from the high carbon content supply device. A molten slag processing apparatus comprising: a molten slag solidifying apparatus having a cooling plate having an approximately U-shaped cross section and an annular shape for rotating and guiding molten slag blown up by a jet of cooling gas.