JP2002234734A - Glass melting furnace - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a glass melting furnace capable of improving the processing capacity without increasing the size. SOLUTION: In a glass melting furnace installed in a highly radioactive liquid waste vitrification facility 13, a melting chamber 1 for melting raw material glass and a side chamber 15 communicating with the melting chamber 1 at the bottom at a melting furnace main body 14. And a side chamber 15 from outside.
Air supply device 19 for feeding pressurized air into the upper space of
Is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a glass melting furnace installed in a highly radioactive liquid waste vitrification facility.

[0002]

2. Description of the Related Art Highly radioactive liquid waste generated in nuclear facilities is melted by a glass melting furnace of a highly radioactive liquid waste vitrification facility, treated as vitrified material, and stored in a radioactive waste storage facility.

[0003] In the above-mentioned vitrification facility, highly radioactive waste liquid is mixed when raw glass is melted inside a glass melting furnace, and the molten glass mixed with this highly radioactive waste liquid is poured into a solidification vessel, and the molten glass is melted. By solidifying,
A vitrified body is formed.

FIG. 2 is a vertical sectional front view showing an example of a conventional glass melting furnace, and FIG. 3 is a vertical sectional side view of FIG.
2 is a melting furnace main body. The melting furnace main body 2 has a corrosion-resistant refractory brick 2 so as to form a melting space 1 therein.
a.

A main electrode 3 is provided on the left and right sides of the upper and lower middle portions of the melting furnace body 2 so as to face each other.
A bottom electrode 5 is provided on the narrowed furnace bottom 4 below the melting space 1, and an inner end of the bottom electrode 5 projects into the melting space 1. 2 and 3, reference numeral 6 denotes a raw material supply port provided on the upper part of the melting furnace main body 2 to supply raw glass, highly radioactive waste liquid, etc., 7 denotes a waste gas outlet pipe,
8 is a waste gas treatment device, 9 is an auxiliary electrode, 10 is a glass outlet for taking out the molten glass formed on the furnace bottom 4, 11 is a heater for heating the glass outlet 10, and G is molten glass. It is.

In the above glass melting furnace, the raw glass and the highly radioactive waste liquid are supplied to a melting space 1 (hereinafter referred to as a melting chamber 1) formed in a melting furnace main body 2, and the main electrodes 3, which are disposed opposite to each other.
The raw glass is melted by Joule heat generated by the current flow (discharge) between the three, and the molten glass G is taken out from the glass outlet 10 at the bottom of the melting chamber 1.

[0007]

By the way, the glass in the melting chamber 1 is in a stationary state, so that the heat transfer rate during heating by the main electrodes 3 is relatively low. In addition, a calcined layer 12 is formed on the upper surface of the melting chamber 1, and the calcined layer 12 suppresses the transmission of heat to the upper space of the melting chamber 1. Layer 1
The transmission of heat to the raw material glass supplied to the upper portion of No. 2 is suppressed, and there is a problem that the melting efficiency is reduced.

For this reason, conventionally, the processing amount in the glass melting furnace, that is, the melting processing amount of the raw glass, is assumed to be substantially proportional to the volume of the melting chamber 1 (particularly, the area of the upper surface of the molten glass G). Therefore, in order to increase the throughput, it is conceivable to enlarge the entire glass melting furnace.

However, when the size of the glass melting furnace is increased, the amount of the corrosion-resistant refractory bricks 2a used for constructing the furnace is increased, and furthermore, the building for accommodating the glass melting furnace and the handling equipment such as a crane are also increased in size. In addition, there is a problem that construction costs are significantly increased.

An object of the present invention is to provide a glass melting furnace capable of improving the processing capacity without increasing the size of the equipment configuration.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a glass melting furnace installed in a highly radioactive liquid waste vitrification facility.
A stir-air supply device for providing a melting chamber for melting the raw material glass and a side chamber communicating with the melting chamber at the bottom in the melting furnace body, and further for feeding pressurized air from outside the vitrification facility to an upper space of the side chamber. Provided in the glass melting furnace.

In the above means, the stirring air supply device is
An air supply pipe for supplying pressurized air from the outside of the vitrification facility to the upper space of the side chamber, an air release pipe branched from the air supply pipe and communicating with the upper space of the melting chamber, and the air supply pipe. The air conditioner may include a first regulating valve and a second regulating valve disposed in the air release pipe.

In the melting chamber, if the entire region of the molten glass underneath, including the calcined layer formed on the surface of the molten glass, can be efficiently heated, the processing speed can be increased and the throughput can be increased.

In the present invention, from such a viewpoint, the molten glass in the melting chamber is agitated. That is, pressurized air is sent to the upper space of the side chamber to push down the molten glass surface in the side chamber. Then, since the bottom of the side chamber is connected to the melting chamber, the molten glass in the side chamber flows into the melting chamber through the communication path, whereby the molten glass in the melting chamber flows.

Further, by controlling the opening and closing of the first regulating valve and the second regulating valve to release the pressurized air supplied to the upper space of the side chamber by the air release pipe into the upper space of the melting chamber, the melting of the melting chamber is started. A part of the glass flows back to the side chamber, and the molten glass surface of the melting chamber descends. When the above operation is repeated, the heat transfer coefficient is increased by the molten glass repeatedly flowing between the melting chamber and the side chamber, so that heat is quickly transmitted to the entire molten glass including the calcined layer, and the processing speed is improved. .

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional front view of a glass melting furnace according to an embodiment of the present invention. In the figure, the same components as those in FIGS. 2 and 3 are denoted by the same reference numerals, and detailed description is omitted.

A melting furnace main body 14 of a glass melting furnace is provided inside the vitrification facility 13. The melting furnace body 14
A melting chamber 1 for melting the raw material glass and a side chamber 15 for flowing (stirring) the molten glass G in the melting chamber 1 are provided.

A side portion near the bottom of the melting chamber 1 and a bottom of the side chamber 15 are connected by a communication path 16. In the melting chamber 1,
A main electrode 3 is provided so as to face the paper surface in a vertical direction, and the raw material glass is melted by Joule heat by energization (discharge) between the main electrodes 3 and 3. An electric heater 17 is also provided in the side chamber 15 to heat the molten glass G in the side chamber 15 so that the temperature of the molten glass G does not drop and harden.

Since the melting chamber 1 and the side chamber 15 are connected by the communication passage 16, the heights of both molten glass surfaces are usually equal. A glass outlet 10 is provided at the bottom of the melting chamber 1.
Is provided, and a bottom electrode 5 is provided so as to surround the glass outlet 10.

Outside the vitrification facility 13, an air tank (accumulator) 18 is provided. In the air tank 18, pressurized air (compressed air) is sent to the melting furnace main body 14 to melt the molten glass G. A stirring air supply device 19 adapted to perform stirring is connected.

The stirring air supply device 19 includes an air supply pipe 20 for supplying pressurized air from an air tank 18 outside the vitrification facility 13 to an upper space of the side chamber 15, and branches from the air supply pipe 20. An air release pipe 21 communicating with the upper space of the melting chamber 1, a first control valve 22 disposed on the air supply pipe 20, and a second control valve 23 disposed on the air release pipe 21 are provided. A manual safety valve 24 is provided outside the vitrification facility 13 in the air supply pipe 20, and a main valve 25 is provided upstream of the air tank 18.

Next, the operation of the above embodiment will be described.

The raw material glass and the highly radioactive waste liquid are supplied from above the melting chamber 1 and the raw glass is melted by Joule heat generated by energization (discharge) between the opposed main electrodes 3.

Here, the first regulating valve 22 is closed, and the main valve 25 is closed.
Is opened, pressurized air is stored in the air tank 18. afterwards,
When the main valve 25 and the second regulating valve 23 are closed and the first regulating valve 22 is opened, the pressurized air in the air tank 18 is supplied to the upper space of the side chamber 15 through the air supply pipe 20.

Then, the surface of the molten glass G in the side chamber 15 is pushed down to a predetermined height L ₁ (position indicated by a broken line) by the pressurized air, whereby the molten glass G in the side chamber 15 is melted through the communication passage 16. By moving to the chamber 1, a flow S occurs at the position of the melting chamber, and the surface of the molten glass G in the melting chamber 1 rises to a required height L ₂ (position indicated by a broken line).

Next, the second regulating valve 23 is opened and the side chamber 15 is opened.
When the pressurized air inside is released into the upper space of the melting chamber 1, a part of the molten glass G in the melting chamber 1 flows so as to return to the side chamber 15, and the molten glass G surface of the melting chamber 1 descends. At this time, since the pressurized air in the side chamber 15 is allowed to escape to the melting chamber 1, the contaminated pressurized air can be processed together with the gas in the upper space of the melting chamber 1 without separately processing. it can.

By repeating the above operation, the molten glass G repeatedly moves between the melting chamber 1 and the side chamber 15, and the molten glass G in the melting chamber 1 is effectively stirred by the flow S at this time. As a result, Joule heat generated by energization of the main electrode 3 is quickly transmitted to the entire area of the molten glass G,
Therefore, the heat transfer to the calcined layer 12 shown in FIGS. 2 and 3 also increases, and as a result, the processing speed by the melting furnace main body 14 is increased, and the throughput can be increased. In the stirring air supply device 19, the main valve 25, the first regulating valve 22, and the second regulating valve 23 are provided outside the vitrification facility 13.
The simple operation of opening and closing the molten glass G
Can be effectively stirred.

As described above, by stirring the molten glass G, the throughput of the melting furnace body 14 can be increased. Therefore, when the same throughput is processed as in the prior art, the structure of the melting furnace body 14 is changed to the conventional one. The size can be significantly reduced as compared with the case of FIG.

[0030]

As described above, according to the present invention, the flow of the molten glass is generated in the melting chamber connected to the side chamber by sending pressurized air to the upper side of the side chamber to push down the surface of the molten glass in the side chamber. By repeating the operation of returning the molten glass in the melting chamber to the side chamber by releasing the pressurized air supplied to the upper space of the side chamber to the upper space of the melting chamber, the molten glass is moved between the melting chamber and the side chamber. The heat transfer coefficient is increased by flowing repeatedly between the layers, so that heat is quickly transmitted to the entire area of the molten glass including the calcined layer, thereby increasing the processing speed and increasing the throughput.

As described above, since the amount of processing by the melting furnace body can be increased, when processing the same amount of processing as in the past, there is an effect that the configuration of the melting furnace body can be significantly reduced in size as compared with the conventional case.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a glass melting furnace according to an embodiment of the present invention.

FIG. 2 is a vertical sectional front view showing an example of a conventional glass melting furnace.

FIG. 3 is a vertical sectional side view of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melting chamber (melting space) 13 Vitrification facility 14 Melting furnace main body 15 Side chamber 19 Stirred air supply device 20 Air supply pipe 21 Air release pipe 22 First regulating valve 23 Second regulating valve G Molten glass S Flow

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G21F 9/16 541 G21F 9/16 541L 9/30 519 9/30 519K

Claims (2)

[Claims] In a glass melting furnace installed in a highly radioactive waste liquid vitrification facility, a melting chamber for melting raw material glass and a side chamber communicating with the melting chamber at a bottom portion are provided in a melting furnace main body. A glass melting furnace further comprising a stirring air supply device for feeding pressurized air from outside the vitrification facility to an upper space of the side chamber. 2. An air supply pipe for supplying pressurized air from outside the vitrification facility to the upper space of the side chamber, and air branched from the air supply pipe and communicating with the upper space of the melting chamber. A relief pipe, and a first pipe arranged in the air supply pipe.
The glass melting furnace according to claim 1, further comprising: a regulating valve; and a second regulating valve disposed on the air release pipe.