JP3761753B2 - Safety valve for melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a melting furnace safety valve, and more particularly to a melting furnace safety valve that can reliably prevent leakage of melting furnace gas due to adhesion of low-boiling substances contained in melting furnace gas.
[0002]
[Prior art]
Conventionally, for example, in order to effectively use incineration ash (main ash) discharged from a waste incinerator, the incineration ash is heated to a high temperature in an ash melting furnace to convert the incineration ash into molten slag, and this molten slag is cooled and solidified. Then, it is crushed to a predetermined particle size and used for roadbed materials, aggregates and the like.
[0003]
There are various ash melting furnaces, one of which is an electric resistance type ash melting furnace. The ash melting furnace will be described below with reference to the drawings.
[0004]
FIG. 5 is a schematic configuration diagram showing a conventional ash melting furnace, and FIG. 6 is a cross-sectional view showing a safety valve in the conventional ash melting furnace.
[0005]
5 and 6, 1 is a waste incinerator and 2 is an electric resistance ash melting furnace. The ash melting furnace 2 has three electrodes 14, and the tip of each electrode 14 penetrates the incinerated ash layer 15 and is immersed in the molten slag layer 16. When energized between the electrodes 14, since the molten slag layer 16 is a conductor, the molten slag is heated by electric resistance heat (Joule heat), and the incinerated ash covering the surface is melted. The molten slag is appropriately discharged from the molten slag discharge port 18 to the outside of the furnace, and the molten metal is appropriately discharged from the molten metal discharge port 19 to the outside of the furnace. The molten metal is a metal in the ash melted and collected at the furnace bottom.
[0006]
3 is an ash hopper for storing the incinerated ash from the waste incinerator 1 and putting it into the ash melting furnace 2, and 4 is for burning the melting furnace exhaust gas containing combustible components from the ash melting furnace 2. The combustion chambers 5 and 5 are furnace pressure adjusting dampers provided in the exhaust gas inlet duct of the combustion chamber 4.
[0007]
As shown in FIG. 6, 6 is a conventional safety valve for a melting furnace of a counterweight type. The safety valve 6 contacts the valve body 6A and the valve seat 6B provided at the safety valve outlet 2A at the top of the melting furnace 3 by metal touch, and when the furnace pressure exceeds a predetermined value, the weight (valve body 6A The valve body 6A is opened against the weight of), thereby allowing the gas in the melting furnace to escape to the outside of the furnace and maintaining the furnace pressure at a steady pressure. Reference numeral 17 denotes a hood provided on the safety valve 6. The hood 17 is connected to the safety valve duct 20 </ b> A and sucks melting furnace exhaust gas leaked from the safety valve 6.
[0008]
7 is a dust collector for collecting dust contained in the melting furnace exhaust gas from the combustion chamber 4 and in the melting furnace gas from the safety valve 6, and 8 is a dust collector for collecting the melting furnace exhaust gas and the melting furnace gas via the dust collector 7. A blower 9 for suction is a chimney for releasing clean gas from the blower 8 to the atmosphere.
[0009]
10 is a boiler for effectively using the thermal energy of the high-temperature incinerator exhaust gas from the waste incinerator 1, and 11 is harmful for removing harmful components from the low-temperature exhaust gas after heat exchange by the boiler 10. The gas removal device 12 is a dust collector for removing dust contained in the incinerator exhaust gas from which harmful components have been removed by the harmful gas removal device 11, and 13 is the harmful gas removal device 10 and the dust collector 12 for removing the incinerator exhaust gas. It is a blower for sucking incinerator exhaust gas through.
[0010]
According to the conventional ash melting furnace configured as described above, the incinerated ash is melted as follows.
[0011]
The incinerated ash discharged from the garbage incinerator 1 is stored in the ash hopper 3, and an appropriate amount is charged from the ash hopper 3 into the ash melting furnace 2. The incinerated ash charged into the ash melting furnace 2 is melted on the molten slag heated to a high temperature of several hundreds of degrees by electric resistance heat generated by energization between the electrodes 14, and becomes molten slag and accumulates at the bottom of the furnace. The molten slag at the bottom of the furnace is appropriately discharged from the molten slag 18 to the outside of the furnace, cooled and solidified, and reused as roadbed material or aggregate. The molten metal at the bottom of the furnace is appropriately discharged from the molten metal discharge port 19 to the outside of the furnace for effective use.
[0012]
The melting furnace exhaust gas generated during the heating and melting process of the incineration ash is sent to the combustion chamber 4 where combustible components in the melting furnace exhaust gas are combusted. The melting furnace exhaust gas in which the combustible component is burned is sent to the dust collector 7, where the dust is removed. The melting furnace exhaust gas thus cleaned is dissipated from the chimney 9 to the atmosphere.
[0013]
When the furnace pressure exceeds a predetermined value, the safety valve 6 is opened, and the gas in the melting furnace is released outside the furnace until the furnace pressure reaches a steady value. The melting furnace gas thus released is sent to the dust collector 7 through the safety valve duct 20 </ b> A and the exhaust gas duct 20.
[0014]
On the other hand, the high-temperature incinerator exhaust gas from the waste incinerator 1 is sent to the boiler 10, and after heat exchange there, it is sent to the harmful gas removal device 11. The incinerator exhaust gas from which harmful gas has been removed is sent to the dust collector 12, where dust is removed. And it is diffused from the chimney 9 to the atmosphere.
[0015]
[Problems to be solved by the invention]
However, in the safety valve 6 in the conventional ash melting furnace described above, the valve body 6A and the valve seat 6B provided at the safety valve outlet 2A at the top of the melting furnace 3 come into contact with each other by metal touch, and the furnace pressure exceeds a predetermined value. Since the valve body 6A is opened against the weight of the weight by the furnace pressure, the low boiling point of KCl, NaCl, Pb, Zn, etc. contained in the gas in the melting furnace in the valve body 6A and the valve seat 6B. The substance adheres and solidifies, and a gap is formed between the valve body 6A and the valve seat 6B, thereby impairing the sealing performance between the valve body 6A and the valve seat 6B by metal touch.
[0016]
As described above, if the sealing performance between the valve body 6A and the valve seat 6B is impaired, the pressure inside the furnace does not become a pressure for operating the safety valve 6, for example, 2000 Pa, a slight plus within the control range of the furnace pressure adjusting damper 5. Even at a pressure, for example, 30 to 70 Pa, the gas in the melting furnace leaks from the safety valve 6 to the outside of the furnace.
[0017]
The leaked melting furnace gas is sucked into the melting furnace gas system by the hood 17 on the safety valve 6, but the reducing gas in the furnace such as CO in the leaking gas is mixed with the melting furnace exhaust gas, and the safety valve 6 There was a risk that the CO component in the melting furnace exhaust gas would exceed the exhaust gas standard even at the steady time when it did not operate.
[0018]
Accordingly, an object of the present invention is to provide a safety valve for a melting furnace that can surely prevent leakage of the gas in the melting furnace to the outside due to adhesion of a low-boiling substance contained in the gas in the melting furnace. is there.
[0019]
[Means for Solving the Problems]
First aspect of the present invention, attached to a melting furnace, a Mizufushiki safety valve for releasing the melting furnace gases exceeds a predetermined pressure to the outside of the furnace, the melting furnace, the furnace gas vent A water tank provided around the safety valve outlet formed at the upper end, a valve body that can be freely opened and closed, and a hood that is attached to the lower end of the safety valve duct connected to the safety valve outlet and is disposed on the upper part of the water tank, The valve body is characterized in that it is constituted by a valve body that covers the safety valve outlet, and a skirt whose lower part is immersed in the water tank .
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment when the present invention is applied to a safety valve of an ash melting furnace will be described with reference to the drawings.
[0022]
FIG. 1 is a schematic configuration diagram showing an ash melting furnace equipped with a safety valve of the present invention, FIG. 2 is a partial sectional view showing a safety valve for a melting furnace of the present invention, and FIG. 4 is a partial cross-sectional view showing the safety valve for a melting furnace of the present invention in which the hood is retracted.
[0023]
1 to 4, the same reference numerals as those in FIGS. 5 and 6 denote the same items. That is, 1 is a waste incinerator, 2 is an electric resistance ash melting furnace having three electrodes 14, and 3 is for storing incineration ash from the waste incinerator 1 and putting it into the ash melting furnace 2. The ash hopper 4 is a combustion chamber for burning the melting furnace exhaust gas containing combustible components from the ash melting furnace 2, and 5 is a furnace pressure adjusting damper provided in the exhaust gas inlet duct of the combustion chamber 4, 7 is a dust collector for collecting dust contained in the melting furnace exhaust gas from the combustion chamber 4 and in the melting furnace gas from the safety valve 6, and 8 is a dust collector for collecting the melting furnace exhaust gas and the melting furnace gas via the dust collector 7. A blower 9 for suction is a chimney for releasing clean gas from the blower 8 to the atmosphere.
[0024]
10 is a boiler for effectively using the thermal energy of the high temperature incinerator exhaust gas from the waste incinerator 1, 11 is harmful for removing harmful components from the low temperature exhaust gas after heat exchange by the boiler 10. The gas removal device 12 is a dust collector for removing dust contained in the incinerator exhaust gas from which harmful components have been removed by the harmful gas removal device 11, and 13 is the harmful gas removal device 10 and the dust collector 12 for removing the incinerator exhaust gas. It is a blower for sucking incinerator exhaust gas through.
[0025]
21 is a water-sealed safety valve of the present invention. The safety valve 21 includes a water tank 22 provided around the safety valve outlet 2A of the ash melting furnace 2, a valve body 24 that can be opened and closed around a shaft 23, and a retreat attached to the lower end of a safety valve duct 20A connected to the safety valve outlet 2A. It consists of a possible hood 25. The valve body 24 includes a valve body 26 that covers the safety valve outlet 2 </ b> A, and a skirt 27 that is provided around the valve body 26 and has a lower part immersed in the water tank 22. A furnace gas vent hole 28 is formed at the upper end of the safety valve outlet 2A. The hood 25 is arranged on the upper part of the water tank 22 so as to be rotatable around a shaft 29 by removing the flange fastening bolt 35. Water is supplied into the water tank 22 from the water supply pipe 30. The water overflowed from the water tank 22 is drained from the drain port 31 of the overflow receiver 34.
[0026]
According to the ash melting furnace having the safety valve of the present invention configured as described above, the incinerated ash is melted as follows.
[0027]
The incinerated ash discharged from the garbage incinerator 1 is stored in the ash hopper 3, and an appropriate amount is charged from the ash hopper 3 into the ash melting furnace 2. The incinerated ash charged into the ash melting furnace 2 is melted on the molten slag heated to a high temperature of several thousand degrees by the electric resistance heat generated by energization between the electrodes 14, and becomes molten slag and accumulates in the furnace bottom. The molten slag at the bottom of the furnace is appropriately discharged from the molten slag 18 to the outside of the furnace, cooled and solidified, and reused as roadbed material or aggregate. The molten metal at the bottom of the furnace is appropriately discharged from the molten metal discharge port 19 to the outside of the furnace for effective use.
[0028]
The melting furnace gas generated during the heating and melting process of the incineration ash is sent from the exhaust gas outlet 2B to the combustion chamber 4 where the combustible components in the melting furnace exhaust gas are combusted. The melting furnace exhaust gas in which the combustible component is burned is sent to the dust collector 7, where the dust is removed. The melting furnace exhaust gas thus cleaned is dissipated from the chimney 9 to the atmosphere.
[0029]
When the furnace pressure exceeds a predetermined value, the safety valve 21 is opened, that is, the molten furnace gas passes from the safety valve outlet 2A through the furnace gas vent hole 28, breaks the water seal, and goes out of the safety valve outlet 2A. The melting furnace gas that has flowed out of the safety valve outlet 2A is sucked by the hood 25, passes through the safety valve duct 20A, and escapes outside the furnace until the furnace pressure reaches a predetermined value . The gas in the melting furnace escaped in this way is merged with the melting furnace exhaust gas in the exhaust gas duct 20 through the safety valve duct 20 </ b> A and sent to the dust collector 7.
[0030]
On the other hand, the high-temperature incinerator exhaust gas from the waste incinerator 1 is sent to the boiler 10, and after heat exchange there, it is sent to the harmful gas removal device 11. The incinerator exhaust gas from which the harmful gas has been removed is sent to the dust collector 13 where the dust is removed. And it is diffused from the chimney 9 to the atmosphere.
[0031]
Thus, by making the safety valve 21 water-sealed, the conventional safety valve has the problem of leakage of gas in the melting furnace due to adhesion of low-boiling substances, and the safety valve 21 does not operate due to this leakage. The problem that the CO component in the gas in the melting furnace may exceed the exhaust gas standard at all times is solved.
[0032]
As shown in FIGS. 2 and 3, the low boiling point substance 32 is inevitably attached to the inner surface of the safety valve outlet 2A, and the diameter of the safety valve outlet 2A is thereby narrowed, and eventually the safety valve outlet 2A may be blocked. There is sex. In such a situation, the function of the safety valve 21 is lost, and the furnace pressure rises abnormally, resulting in a very dangerous situation.
[0033]
Therefore, it is necessary to periodically remove the low boiling point substance 32 adhering to the inner surface of the safety valve outlet 2A. In order to remove the low boiling point substance 32, as shown in FIG. 4, the flange fastening bolt 35 is removed, the hood 25 is pulled by the wire 33 or the like fixed to the hood 25, and the hood 25 is rotated about the shaft 29. Then, the valve body 24 is retracted, and then the valve body 24 is rotated around the shaft 23 to expose the safety valve outlet 2A. And the low boiling point substance 32 adhering to the inner surface of the safety valve outlet 2A is scraped off using a tool. The low boiling point substance 32 scraped off falls into the ash melting furnace 2 and is remelted.
[0034]
In this way, the low boiling point substance 32 attached to the inner surface of the safety valve outlet 2A can be easily removed.
[0035]
The above is an explanation using an ash melting furnace as an example, but it goes without saying that the present invention is also applied to a melting furnace other than an ash melting furnace.
[0036]
【The invention's effect】
As described above, according to the present invention, a safety valve attached to the safety valve outlet of the melting furnace for releasing the gas in the melting furnace exceeding a predetermined pressure to the outside of the furnace is water-sealed. The low-boiling substances contained in the internal gas adhere to the safety valve, which can reliably prevent a part of the melting furnace gas from leaking outside the furnace, and the water-sealed safety valve is connected to the melting furnace. A safety tub attached to the lower end of a safety valve duct connected to the safety valve outlet, and the valve body covers the safety valve outlet. The safety valve outlet is constituted by a valve body and a skirt whose lower part is immersed in the water tank, forming an in-furnace gas vent at the upper end of the safety valve outlet, and arranging the hood on the upper part of the water tank. Industrially useful effects are provided such low boiling substance adhering to the surface can be easily removed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an ash melting furnace equipped with a safety valve of the present invention.
FIG. 2 is a partial cross-sectional view showing a melting furnace safety valve of the present invention.
FIG. 3 is a view on arrow A in FIG. 2;
FIG. 4 is a partial cross-sectional view showing a safety valve for a melting furnace according to the present invention with a hood retracted.
FIG. 5 is a schematic configuration diagram showing a conventional ash melting furnace.
FIG. 6 is a cross-sectional view showing a safety valve in a conventional ash melting furnace.
[Explanation of symbols]
1: Waste incinerator 2: Ash melting furnace 2A: Safety valve outlet 2B: Exhaust gas outlet 3: Ash hopper 4: Combustion chamber 5: Furnace pressure adjustment damper 6: Safety valve 6A: Valve body 6B: Valve seat 7: Dust collector 8: Blower 9 : Chimney 10: Boiler 11: Harmful gas removal device 12: Dust collector 13: Blower 14: Electrode 15: Incinerated ash layer 16: Molten slag layer 17: Hood 18: Molten slag outlet 19: Molten metal outlet 20: Exhaust duct 20A : Safety valve duct 21: Safety valve 22 of this invention: Water tank 23: Shaft 24: Valve body 25: Hood 26: Valve body 27: Skirt 28: Furnace gas vent 29: Shaft 30: Water supply pipe 31: Drain port 32: Low Boiling substance 33: Wire 34: Overflow receiver 35: Flange fastening bolt

Claims (1)

Attached to the melting furnace, a Mizufushiki safety valve for releasing the melting furnace gases exceeds a predetermined pressure to the outside of the furnace,
An upper part of the water tank attached to a lower end of a safety valve duct connected to the safety valve outlet, a water tank provided around a safety valve outlet having an in-furnace gas vent hole formed at the upper end of the melting furnace, an openable / closable valve body. A safety valve for a melting furnace , characterized in that the valve body is configured by a valve body that covers the safety valve outlet and a skirt that has a lower part immersed in the water tank .

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