JP2002249321A - Glass melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass melting furnace capable of enhancing treating capability without increasing its facility to a large size. SOLUTION: The glass melting furnace comprises a melting furnace body 2 with a melting space 1 therein, and a main electrode 3 provided at a vertically middle part in the melting space 1 with which a glass material to be fed is heated to a molten glass G. The inner end of the main electrode 3 is protruded to a higher position above the upper face of the molten glass G in the melting space 1, forming a protruding part 13. Thus, the melting space 1 above the upper face of the molten glass G also can be heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD 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 a nuclear facility is melted together with glass raw materials in a glass melting furnace of a highly radioactive liquid waste vitrification facility, processed as vitrified material, and stored in a radioactive waste storage facility.

In the vitrification facility, a radioactive waste liquid is mixed when a glass raw material is melted inside a glass melting furnace, and the molten glass mixed with the radioactive waste liquid is poured into a solidification vessel to solidify the molten glass. Thereby, a vitrified body is formed.

FIG. 2 is a longitudinal sectional front view showing an example of a conventional glass melting furnace. Reference numeral 2 denotes a melting furnace main body. The melting furnace main body 2 has a corrosion-resistant structure so as to form a melting space 1 therein. It is composed of a refractory brick 2a.

[0005] Main electrodes 3 are provided on the left and right sides of the upper and lower middle portions of the melting furnace body 2 so that the inner ends thereof are exposed to the melting space 1 and the lower part of the melting space 1 is narrowed. The bottom part 4 is provided with a bottom part electrode 5 whose inner end is the melting space 1.
It is exposed to. In FIG. 2, reference numeral 6 denotes a raw material supply port provided at the upper portion of the melting furnace main body 2 for supplying glass, radioactive waste liquid, etc., 7 denotes a waste gas outlet tube, 8 denotes an auxiliary electrode, and 9 denotes a furnace bottom portion. A glass outlet 10 for taking out the molten glass, a heater 10 for heating the glass outlet 9, and G a molten glass.

In the above-mentioned glass melting furnace, a glass material and a highly radioactive waste liquid are supplied to a melting space 1 formed in a melting furnace main body 2, and the glass is heated by Joule heat generated by energization (discharge) between opposed main electrodes 3 and 3. Melt the raw material. At this time,
The normal temperature of the molten glass G is about 1200 ° C.,
The temperature of the space above the molten glass G in the molten space 1 is approximately 5
It is about 00 ° C. The molten glass G has a melting space 1
It is taken out from the glass outlet 9 at the bottom and supplied to a solidification container (not shown).

The highly radioactive liquid waste and the glass raw material supplied to the glass melting furnace are evaporated,
Through the process of drying, calcining, oxidation to oxide, vitrification,
It becomes molten glass G.

At this time, a low-temperature calcined body 11 is present on the upper surface of the molten glass G, and the amount of heat required for the calcined body 11 to be vitrified is transferred from the lower molten glass G. Provided by heat and radiation from the headspace.

[0009] The upper surface of the molten glass G is
Is not completely covered, and a portion (hot top portion H) where the high-temperature molten glass G is exposed is partially formed, and only radiation from the hot top portion H contributes to heat transfer from the upper portion. are doing.

[0010]

However, the calcined body 11 may grow and cover the upper surface of the molten glass G, so that the hot-top portion H may decrease. However, the heat transferred from the high-temperature molten glass G to the upper space is suppressed, so that the transfer of heat to the glass raw material supplied to the upper portion of the calcined body 11 is suppressed, and the melting efficiency is reduced. There is a problem of drastic reduction.

For this reason, the processing amount in the conventional glass melting furnace, that is, the glass processing amount, is considered to be substantially proportional to the volume of the melting space 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 use of the corrosion-resistant refractory bricks 2a for constructing the furnace is increased, and the building in which the glass melting furnace is housed and the handling equipment such as a crane are also increased in size. Therefore, there is a problem that the construction cost is greatly increased.

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

[0014]

In order to achieve the above object, a glass melting furnace according to the present invention has a melting furnace main body having a melting space formed therein, and is provided at an upper and lower intermediate portion of the melting space to supply the melting space. In a glass melting furnace equipped with a main electrode that heats the glass raw material to form a molten glass, a protruding portion was formed by projecting the inner end of the main electrode to a position higher than the upper surface of the molten glass in the melting space. It is characterized by:

[0015] In the glass melting furnace of the present invention, the melting space above the calcined body formed on the upper surface of the molten glass is also heated by the high temperature protruding portion of the main electrode. I do.

[0016]

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

FIG. 1 is a longitudinal sectional front view showing an example of an embodiment of the present invention, and the same parts as those in FIG. 2 are denoted by the same reference numerals.

The main electrodes 3, 3 opposed to each other on the left and right sides of the upper and lower middle portions of the melting furnace main body 2 shown in FIG. The projection 13 is formed by projecting to a position higher than the upper surface of the molten glass G located at the top. The inner end portion 12 of the main electrodes 3 and 3 exposed to the molten glass G has a high temperature substantially equal to the temperature of the molten glass G (about 1200 ° C.). Has become.

Therefore, as described above, the inner end portion 1 is raised to a higher position above the upper surface of the molten glass G in the molten space 1.
In the melting furnace main body 2 provided with the main electrode 3 having the projection 2 protruded, a layer of the calcined body 11 is formed on the upper surface of the molten glass G while the glass raw material is being melted. Even if the glass G almost covers the entire upper surface, the radiant heat from the high temperature protruding portion 13 of the main electrode 3 located above the upper surface of the molten glass G causes the upper portion of the calcined body 11 to be higher. Is also effectively heated, thereby increasing the melting capacity.

Therefore, without increasing the size of the equipment configuration,
The processing capacity of the glass melting furnace can be improved.

[0021]

According to the present invention, the projecting portion projecting to a position higher than the upper surface of the molten glass at the inner end of the main electrode heats the molten space above the calcined body, so that the equipment configuration is large. This has the effect that the processing capacity of the glass melting furnace can be improved without conversion.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing an example of an embodiment of the present invention.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melting space 2 Melting furnace main body 3 Main electrode 12 Inner end 13 Projection G molten glass

Claims (1)

[Claims] 1. A glass comprising: a melting furnace main body having a melting space formed therein; and a main electrode provided at an upper and lower middle part of the melting space and configured to heat a glass raw material to be supplied to the melting space to form molten glass. A glass melting furnace, characterized in that a protruding portion is formed by projecting an inner end of a main electrode to a position higher than a top surface of molten glass in a melting space in the melting furnace.