JPH0717040Y2 - Glass melting furnace - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a glass melting furnace in a vitrification plant for radioactive wastes, and in particular, supplies glass raw materials and radioactive waste liquid in a slurry form. It is about technology.

"Prior Art" Generally, a vitrification plant is provided to vitrify waste such as high-level radioactive waste liquid generated in a facility associated with a nuclear power plant to improve the handling property. In the vitrification plant, as shown in FIG. 3, waste such as radioactive waste liquid and the glass material are fed into the glass melting furnace 3 housed in the airtight chamber 2 of the cell 1 to be melted, and The molten mixture of (1) is filled in another prepared container to be solidified by cooling and further, a series of vitrification treatments such as enclosing helium gas for leakage inspection are carried out.

Then, in the glass melting furnace, for example, the glass material made into a cartridge is dropped from the material supply port 4, and the radioactive waste liquid is merged from the waste liquid supply pipe 5 to allow the glass material to soak into the glass material. The solid content (radioactive granules, etc.) contained in the waste liquid is taken into the molten glass, and the waste liquid is fed to remove off-gas generated in the glass melting furnace 3. The off-guy discharge pipe 6 and the off-gas suction / discharge system 7 using a blower or the like are used to suck and discharge.

[Problems to be Solved by the Invention] In such a glass melting furnace 3, it is desirable to continuously supply a glass material and a waste liquid for continuous treatment in order to improve the operation efficiency. With the method of dropping from the supply port 4, the airtightness in the vicinity thereof is impaired, ambient air and the like are taken in to increase the amount of off-gas treated, and the depressurized atmosphere is affected.
Further, the supply of the glass material is intermittent, the temperature in the furnace fluctuates greatly, and stable operation cannot be performed.

The present invention is intended to effectively solve such a problem, and stabilizes the supply ratio of the glass raw material and the waste liquid, and continuously supplies and continuously operates the processing material without affecting the depressurized atmosphere. The purpose is to do.

"Means for Solving Problems" The glass melting furnace of the present invention is designed to feed radioactive waste and take solids into the glass melting material. An off-gas discharge system that creates an atmosphere and sucks the generated gas, and a slurry-like feed that is a mixture of a glass raw material and a radioactive waste liquid are driven by the load and the suction force of the decompressed atmosphere in the upper space of the furnace. And a slurry supplying means for dropping the slurry into the furnace, and inside the transfer path, the slurry-like supply slides down due to the weight of the slurry-like supply itself, and the slurry-like supply blocks the transfer path. The suction action generated by facing the decompressed atmosphere of the space works in a synergistic state, and the gas is continuously supplied into the furnace.

[Embodiment] An embodiment of the glass melting furnace according to the present invention will be described below with reference to FIGS. 1 and 2. In addition, in one embodiment, the same parts as those in the conventional example are designated by the same reference numerals to simplify the description.

Also in the embodiment, the off-gas exhaust pipe 6 and the off-gas exhaust system 7 are connected to the glass melting furnace 3 so that the upper space 8 in the furnace has a reduced pressure atmosphere. A slurry supply means 9 is continuously provided, and a glass raw material supply system 10 such as a frit and a waste liquid supply tank 11 are connected to the slurry supply means 9.

Then, in the waste liquid supply tank 11, a pressurized gas supply system 12, an air lift 13 operated by the pressurized gas supply system 12, and a waste liquid supply pipe 14 for raising the waste liquid in a gas-liquid mixed state when the air lift 13 is operated. And are provided.

The slurry supply means 9 has a material mixing tank 15 connected to the glass raw material supply system 10 and the waste liquid supply pipe 14, and is dropped into the material mixing tank 15 from the glass raw material supply system 10 by using weight. The mixed glass raw material and the waste liquid and the like are mixed, and a stirrer 16 for forming a slurry, a driving motor 17 for the stirrer 16, and a slurry-like supply material in the material mixing tank 15 It is configured by a slurry supply pipe 18 for transporting to the supply port 4.

Further, as shown in FIG. 1, the slurry supply pipe 18 is arranged in an inclined state so as to have a gradient of an angle θ and gently slides toward the material supply port 4 due to the weight of the slurry-like supply material itself. In addition, the suction force generated by the decompressed atmosphere of the upper space 8 in the furnace is applied to carry the material at a required speed.

In one example, the slurry supply pipe 18 has a maximum length of 8
When the m is 25 mm, the angle of inclination is θ = 20 °, the pressure is −180.
It is set to about mmAq to -200mmAq.

Although the lower end of the slurry supply pipe 18 penetrates the ceiling lid 19 of the material supply port 4 in the example of FIG. 1, it can also penetrate the side part as in the example of FIG. In this case, it is possible to perform a work such as supplying a glass material or the like by opening the lid 19 at the initial stage or when necessary.

The case where the glass melting furnace 3 configured as described above is brought into an operating state will be described. The glass material supply system 10 and the pressurized gas supply system 12 are operated to supply the glass raw material and the waste liquid to the material mixing tank 15, and the stirrer 16 is operated to perform stirring and mixing to produce a slurry-like supply material. When the slurry-like supply material has an appropriate softness, it is pressed downward by its own weight by filling it in the slurry supply pipe 18 which is its conveying path, and the inside of the slurry supply pipe 18 is pressed. Is closed to bring the slurry supply material and the inner surface of the slurry supply pipe 18 into a close contact state (sealed state).

On the other hand, the slurry feed tends to stay in a state of being attached to the inner surface of the slurry feed pipe 18 by viscous force, but due to the weight and inclination of the slurry feed itself, the slurry feed downwards at a speed set by the gradient, viscosity, etc. Operate to the extent that it slips down.

In this case, the operation of the off-gas discharge system 7 creates a depressurized atmosphere in the furnace upper space 8 and, based on this depressurization, sucks the slurry-like feed material that is about to slide down and promotes the slipping. The suction force based on the atmosphere is obtained by the product of the cross-sectional area set by the diameter of the slurry supply pipe 18 and the pressure (reduced pressure).

By such a synergistic force of the weight and the suction force, when the slurry-like feed gradually moves and reaches the material supply port 4 and the furnace upper space 8, the suction force downward is applied to the exposed portion. It stops working, but on the other hand, the viscous force of the slurry-like feed and the weight of the suspended part break the equilibrium state, causing the slurry-like feed to break and falling intermittently onto the glass melting surface. To do.

Alternatively, it is continuously supplied to the glass melting surface while being connected in a string shape.

The supply of the slurry-like supply is easy to set the glass raw material and the waste liquid to have a constant ratio, and,
By mixing at a constant ratio, the downward moving speed is also stabilized, so that the quantitative supply state is easily achieved.

Next, the solid content is taken into the molten glass, and the generated off-gas in the mixed state of water vapor, volatile gas, etc. is taken into the off-gas exhaust system 7 via the off-gas exhaust pipe 6.

The specifications of the portion of the slurry supply pipe 18 described above are such that the length, the bore diameter, the angle of the gradient, and the pressure due to the reduced pressure atmosphere can be arbitrarily set depending on the conditions such as the downward conveying speed.

[Advantages of the Invention] As described above, according to the glass melting furnace of the present invention, the off-gas discharge system is operated to make the upper space in the furnace a depressurized atmosphere, and the slurry supply means makes the glass raw material radioactive. The slurry-like feed formed by mixing with the waste liquid is driven by the load and the suction force of the decompressed atmosphere in the upper space of the furnace to be dropped into the furnace. Inside the passage, the action of sliding down due to the weight of the slurry-like feed itself and the suction action caused by facing the decompressed atmosphere in the upper space of the furnace work in a synergistic state, and the slurry feed is continuously supplied in a controlled state. be able to.

Further, based on the above, since the slurry-like feed descends while keeping the transportation path sealed, it does not affect the depressurized atmosphere, and the glass melting furnace is operated efficiently in a stable state in combination with the material supply at a constant ratio. can do.

And so on.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of a glass melting furnace according to the present invention together with a pipeline, and FIG. 2 is a front sectional view showing another embodiment of the main part of the glass melting furnace shown in FIG. FIG. 3 is a front sectional view showing the concept of the vitrification plant. 3 ... Glass melting furnace, 4 ... Material supply port, 6 ... Off-gas discharge pipe, 7 ... Off-gas discharge system, 8 ... Upper space in furnace, 9 ... Slurry supply means, 10 ... Glass raw material supply system , 11 …… Waste liquid supply tank, 12 …… Pressurized gas supply system, 13 ……
Air lift, 14 …… Waste liquid supply pipe, 15 …… Material mixing tank, 16
…… Agitator, 17 …… Drive motor, 18 …… Slurry supply pipe, 19 …… Lid.

Claims (1)

[Scope of utility model registration request] 1. A glass melting furnace in which radioactive waste is fed so that solids are taken into the glass melt, and an off-gas discharge system for sucking the generated gas while making the upper space in the furnace a depressurized atmosphere. A slurry supply means for driving a slurry-like supply material, which is a mixture of a glass raw material and a radioactive waste liquid, into the furnace by driving the load and the suction force of the decompressed atmosphere in the upper space of the furnace. Glass melting furnace characterized by.