JP2013238458A - Thermal decomposition apparatus for solid organic radioactive waste and thermal decomposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal decomposition apparatus for a solid organic radioactive waste in which a radioactive waste gas treatment device such as a secondary combustion furnace can be small-sized, and a thermal decomposition method.SOLUTION: A thermal decomposition apparatus 1A for a solid organic radioactive waste comprises a thermal decomposition furnace 11, a cooler 12, a condensate tank 15A and a secondary combustion furnace 13. The thermal decomposition furnace 11 creates a combustible thermal decomposition gas 45 by thermally decomposing a solid organic radioactive waste 40 generated from a nuclear facility in an oxygen-free atmosphere. The cooler 12 cools the thermal decomposition gas 45 exhausted from the thermal decomposition furnace 11 and separates the thermal decomposition gas into a condensate 50 and a non-condensable gas 60. The condensate tank 15A stores therein the condensate 50 collected from the cooler 12. The secondary combustion furnace 13 combusts the non-condensable gas 60 exhausted from the cooler 12.

Description

  The present invention relates to a thermal decomposition apparatus and a thermal decomposition method for solid organic radioactive waste.

  Solid organic radioactive waste generated as radioactive waste from a nuclear facility or the like is usually pyrolyzed, made harmless, and then released into the atmosphere.

  As a waste treatment method for thermally decomposing ordinary solid organic waste that is not radioactive waste, for example, a method described in Patent Document 1 (Japanese Patent Laid-Open No. 2004-97879) is known. In the method described in Patent Document 1, the inside of the pyrolysis furnace is maintained in an oxygen-free atmosphere, and the solid organic waste is heated in a static state to thermally decompose the plastics and cellulose in the solid organic waste. The combustible pyrolysis gas is naturally exhausted from the pyrolysis furnace, and after the pyrolysis of the solid organic waste is completed, the carbide-containing residue remaining after the pyrolysis is oxidized and decomposed.

  The method of thermally decomposing solid organic waste while keeping the inside of such a pyrolysis furnace in an oxygen-free atmosphere includes, for example, suppression of dioxin generation, suppression of the amount of gas generated, suppression of the amount of ash generated, etc. Used for reasons.

  An example of a thermal decomposition apparatus used in the method described in Patent Document 1 will be described with reference to the drawings. FIG. 6 is a schematic diagram of an example of a thermal decomposition apparatus used in the method described in Patent Document 1.

  As shown in FIG. 6, a conventional pyrolysis apparatus 2 is a pyrolysis furnace that generates a combustible pyrolysis gas 45 by pyrolyzing a normal solid organic waste 40A that is not radioactive waste in an oxygen-free atmosphere. 11 and a secondary combustion furnace 13 for burning the pyrolysis gas 45 discharged from the pyrolysis furnace 11 through the pyrolysis gas distribution line 71.

  In the pyrolysis furnace 11 of the pyrolysis apparatus 2, first, the solid organic waste 40A is disposed. The solid organic waste 40A generates a carbide-containing residue 80 when a thermal decomposition treatment 91 is performed in which heat treatment is performed in an oxygen-free atmosphere. Further, the carbide-containing residue 80 generates ash 81 when the oxidative decomposition treatment 92 in which heat treatment is performed in an oxygen atmosphere is performed, and the ash 81 is recovered through the residue recovery line 75.

In the case of the pyrolysis treatment 91, a combustible pyrolysis gas 45 is generated in the pyrolysis furnace 11. The pyrolysis gas 45 is sent to the secondary combustion furnace 13 and burned by using combustion air 63 supplied via the air supply line 32.
During the oxidative decomposition treatment 92, an oxidative decomposition gas 86 is generated in the thermal decomposition furnace 11. This oxidative decomposition gas 86 is normally sent to the secondary combustion furnace 13 and is directly discharged from the secondary combustion furnace 13 as the secondary combustion processing gas 85 through the secondary combustion processing gas discharge line 73.

JP 2004-97879 A

  However, when the solid organic waste 40A is a solid organic radioactive waste 40 generated as a radioactive waste from a nuclear facility, the method described in Patent Document 1 cannot be used as it is. That is, as shown in FIG. 6, a flammable pyrolysis gas 45 generated from an organic substance that has reached a pyrolysis temperature by pyrolyzing the solid organic radioactive waste 40 in a pyrolysis furnace 11 in an oxygen-free atmosphere. Is further discharged into the atmosphere after being processed by the secondary combustion furnace 13 or a filter or the like provided downstream of the secondary combustion furnace 13.

  Here, the apparatus which processes the pyrolysis gas 45, such as the secondary combustion furnace 13 and a filter, is called waste gas processing apparatus. The required air flow rate and equipment dimensions of this waste gas treatment device are designed from the amount of pyrolysis gas 45 corresponding to the required treatment capacity of the solid organic waste 40A such as the solid organic radioactive waste 40. That is, when the amount of pyrolysis gas is large, it is usually necessary to enlarge the waste gas treatment apparatus. Here, the amount of pyrolysis gas is the amount of pyrolysis gas 45 that is introduced into the secondary combustion furnace 13 and burnt.

  By the way, a used waste gas treatment apparatus is disposed of as secondary radioactive waste. Specifically, the used waste gas processing apparatus is cut, separated, and stored. For this reason, it is preferable that the waste gas treatment apparatus is miniaturized as much as possible in order to facilitate future disposal.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a solid organic radioactive waste thermal decomposition apparatus and a thermal decomposition method capable of downsizing a waste gas treatment apparatus such as a secondary combustion furnace.

  That is, the solid organic radioactive waste pyrolysis apparatus of the present invention is for solving the above-mentioned problems, and the solid organic radioactive waste is pyrolyzed in an oxygen-free atmosphere to generate a combustible pyrolysis gas. A pyrolysis furnace, a cooler that cools the pyrolysis gas discharged from the pyrolysis furnace and separates it into a condensate and a non-condensable gas, and a condensate that contains the condensate recovered from the cooler It has a tank and a secondary combustion furnace which burns noncondensable gas discharged from the cooler.

  In addition, the solid organic radioactive waste pyrolysis method of the present invention is for solving the above-mentioned problems, and the solid organic radioactive waste is pyrolyzed in an oxygen-free atmosphere to generate a combustible pyrolysis gas. A pyrolysis step, a cooling separation step for cooling the pyrolysis gas to separate it into a condensate and a non-condensable gas, a recovery step for collecting the condensate, and a non-condensable gas in a secondary combustion furnace And a secondary combustion step of burning in the step.

  According to the pyrolysis apparatus and pyrolysis method for solid organic radioactive waste of the present invention, a waste gas treatment apparatus such as a secondary combustion furnace can be downsized.

Schematic of 1st Embodiment of the thermal decomposition apparatus of the solid organic radioactive waste of this invention. An example of the flow of the thermal decomposition process using 1st Embodiment of the thermal decomposition apparatus of the solid organic radioactive waste of this invention. Schematic of 2nd Embodiment of the thermal decomposition apparatus of the solid organic radioactive waste of this invention. Schematic explaining a part of 2nd Embodiment of the thermal decomposition apparatus of the solid organic radioactive waste of this invention. An example of the flow of the thermal decomposition process using 2nd Embodiment of the thermal decomposition apparatus of the solid organic radioactive waste of this invention. Schematic of the conventional thermal decomposition apparatus.

[Pyrolysis device]
The thermal decomposition apparatus of the solid organic radioactive waste of this invention is demonstrated with reference to drawings.

(First embodiment)
FIG. 1 is a schematic view of a first embodiment of the thermal decomposition apparatus for solid organic radioactive waste according to the present invention.
A pyrolysis apparatus 1A for solid organic radioactive waste shown in FIG. 1 includes a pyrolysis furnace 11 that pyrolyzes solid organic radioactive waste 40, and a cooler that cools pyrolysis gas 45 discharged from the pyrolysis furnace 11. 12, a condensate tank 15 </ b> A that stores the condensate 50 collected by the cooler 12, and a secondary combustion furnace 13 that burns the non-condensable gas 60 discharged from the cooler 12.

<Pyrolysis furnace>
The pyrolysis furnace 11 is for pyrolyzing a solid organic radioactive waste 40 generated from a nuclear facility or the like in an oxygen-free atmosphere to generate a combustible pyrolysis gas 45.
Here, the solid organic radioactive waste 40 is, for example, solid organic waste generated as radioactive waste from a nuclear facility. Examples of the solid organic radioactive waste 40 include a resin container, a resin sheet, packing, clothes, waste paper, cloth scraps, tools, waste equipment, materials, and a filter used for work in a nuclear facility.

The oxygen-free atmosphere is an atmosphere made of an inert gas such as water vapor, nitrogen gas, carbon dioxide gas, for example. Here, the oxygen-free atmosphere is used to mean an atmosphere containing a slight amount of oxygen in addition to an atmosphere containing no oxygen.
The heat treatment temperature in the pyrolysis furnace 11 is, for example, 200 to 900 ° C.

  The pyrolysis gas 45 is a gas containing a combustible gas generated by pyrolysis of the solid organic radioactive waste 40 in an oxygen-free atmosphere. Moreover, the pyrolysis gas 45 normally contains solid contents such as tar vapor such as C8 to C20 hydrocarbons and fine ash in addition to the combustible gas.

  Examples of the combustible gas include one or more of hydrocarbons having a low carbon number such as methane, ethylene, and propylene, carbon monoxide, and hydrogen.

  Further, since the pyrolysis gas 45 is at a high temperature, it includes a substance that is liquid or solid at room temperature but is vaporized due to the high temperature. Examples of the substance that is liquid or solid at normal temperature but is vaporized due to high temperature include tars such as hydrocarbons of about C8 to C20.

Further, since the pyrolysis gas 45 is flowing in the pyrolysis furnace 11, it usually includes fine solids generated in the pyrolysis furnace 11. Examples of the fine solid include ash.
The pyrolysis furnace 11 is connected to a pyrolysis gas distribution line 21 that sends the pyrolysis gas 45 generated in the pyrolysis furnace 11 to the cooler 12.

<Cooler>
The cooler 12 cools the pyrolysis gas 45 discharged from the pyrolysis furnace 11 and separates it into a condensate 50 and a non-condensable gas 60.
Specifically, the cooler 12 is connected to the pyrolysis furnace 11 via the pyrolysis gas distribution line 21, cools the pyrolysis gas 45 discharged from the pyrolysis furnace 11, and then decomposes the pyrolysis gas 45. Is separated into a condensate 50 and a non-condensable gas 60 composed of a liquid or solid.

As the cooler 12, for example, an air-cooled condenser is used. When an air-cooled condenser is used, the outer surface temperature of the air-cooled condenser is set to 20 to 50 ° C., for example. Thereby, the pyrolysis gas 45 is normally cooled to 100 ° C. or lower, preferably 20 to 50 ° C. By this cooling, the pyrolysis gas 45 generates a condensate 50 obtained by liquefaction or solidification. Further, the remainder obtained by removing the condensate 50 from the pyrolysis gas 45 becomes a gaseous noncondensable gas 60.
The cooler 12 includes a discharge portion for the condensate 50 and a discharge portion for the non-condensable gas 60 in addition to the introduction portion for the pyrolysis gas 45 connected to the pyrolysis gas distribution line 21.

The condensate 50 generated by the cooler 12 is usually a mixture of liquid and solid, and includes, for example, liquid liquefied organic matter, liquid water, and solids such as ash and sludge. As a liquid liquefied organic substance, the oil which consists of about C8-C20 polymeric hydrocarbon is mentioned, for example.
When the condensate 50 contains liquefied organic matter, water, and sludge, when the condensate 50 is left standing, the condensate 50 is usually separated into a layer made of liquefied organic matter, a layer made of water, and a layer made of sludge. Is done.

The non-condensable gas 60 generated by the cooler 12 is a substance that maintains a gaseous state even when the pyrolysis gas 45 is cooled by the cooler 12.
The non-condensable gas 60 is usually a gas mainly containing a combustible gas. Examples of the combustible gas contained in the non-condensable gas 60 include one or more of low-carbon hydrocarbons such as methane, ethylene, and propylene, carbon monoxide, and hydrogen. Moreover, the non-condensable gas 60 may contain solids, such as ash.

<Condensate tank>
The condensate tank 15 </ b> A accommodates the condensate 50 recovered from the cooler 12.
Specifically, the condensate tank 15 </ b> A is connected to the discharge part of the condensate 50 of the cooler 12 via the condensate recovery line 25 and accommodates the condensate 50 discharged from the cooler 12.
The condensate tank 15 </ b> A includes a waste liquid discharge unit 35 for discharging the waste liquid composed of the condensate 50.

  The condensate 50 accommodated in the condensate tank 15 </ b> A is discarded as the waste liquid 50 through the waste liquid discharge line 33 connected to the waste liquid discharge portion 35. The waste liquid 50 usually contains liquefied organic matter, liquid water, and solids such as ash and sludge.

<Secondary combustion furnace>
The secondary combustion furnace 13 burns the non-condensable gas 60 discharged from the cooler 12.
Specifically, the secondary combustion furnace 13 is connected to the discharge part of the non-condensable gas 60 of the cooler 12 via the non-condensable gas distribution line 22 and is supplied with air for combustion 63. The line 32 is connected, and the non-condensable gas 60 discharged from the cooler 12 is burned in the furnace.
As the secondary combustion furnace 13, for example, a combustion furnace having a burner (not shown) is used.

  The heat treatment temperature in the secondary combustion furnace 13 is, for example, 900 ° C. or higher. When the heat treatment temperature in the secondary combustion furnace 13 is 900 ° C. or higher, generation of hardly decomposable organic substances such as dioxins can be suppressed.

  The non-condensable gas 60 is generally composed of a combustible gas containing one or more of low-carbon hydrocarbons such as methane, ethylene, and propylene, carbon monoxide, and hydrogen. For this reason, when the non-condensable gas 60 is supplied with combustion air in the secondary combustion furnace 13 and is heat-treated, the non-condensable gas 60 is combusted and a secondary combustion processing gas 65 mainly containing carbon dioxide, water, etc. is generated.

  The secondary combustion processing gas 65 is exhausted from the secondary combustion furnace 13 and circulates through the secondary combustion processing gas discharge line 23, and further subjected to waste gas processing with a waste gas processing device such as a filter (not shown), and then into the atmosphere. To be released.

<Action>
With reference to FIG. 1 and FIG. 2, the effect | action of 1 A of thermal decomposition apparatuses shown as 1st Embodiment is demonstrated. FIG. 2 is an example of the flow of the thermal decomposition process using the first embodiment of the thermal decomposition apparatus of the present invention. Hereinafter, the operation when the cooler 12 is an air-cooled condenser will be described.

  First, the solid organic radioactive waste 40 generated from a nuclear facility (not shown) is installed in the pyrolysis furnace 11 (step S101).

  Next, a thermal decomposition process is performed. The pyrolysis process is a process in which the solid organic radioactive waste 40 is pyrolyzed in an oxygen-free atmosphere to generate a combustible pyrolysis gas 45.

For example, in the pyrolysis step, first, an inert gas is injected into the pyrolysis furnace 11 to make the inside of the pyrolysis furnace 11 an oxygen-free atmosphere (step S102).
In the pyrolysis step, secondly, the solid organic radioactive waste 40 is pyrolyzed in the pyrolysis furnace 11 in an oxygen-free atmosphere (step S103). The heat treatment temperature in the pyrolysis furnace 11 is, for example, 200 to 900 ° C.
When the solid organic radioactive waste 40 is pyrolyzed in step S103, a pyrolysis gas 45 is generated from the solid organic radioactive waste 40 in the pyrolysis furnace 11 (step S104).

  The pyrolysis gas 45 usually contains a combustible gas, a vapor of tar such as C8 to C20 hydrocarbons, and a solid content such as fine ash. Here, the flammable gas is, for example, a gas composed of one or more of hydrocarbons having a low carbon number such as methane, ethylene, propylene, carbon monoxide, and hydrogen.

  The generated pyrolysis gas 45 is sent from the pyrolysis furnace 11 to the air-cooled condenser 12 as a cooler via the pyrolysis gas distribution line 21.

  Next, a cooling separation process is performed using the pyrolysis gas 45. The cooling separation step is a step of cooling the pyrolysis gas 45 to separate it into a condensate 50 and a non-condensable gas 60.

For example, in the air-cooled condenser 12, the outer surface temperature of the air-cooled condenser is adjusted to be 20 to 50 ° C., for example, and the pyrolysis gas 45 is cooled (step S105).
Part of the pyrolysis gas 45 cooled by the air-cooled condenser (cooler) 12 is liquefied or solidified to produce a condensate 50, and the remainder becomes a gaseous noncondensable gas 60.

The condensate 50 typically includes liquid liquefied organic matter, liquid water, and solids such as ash and sludge.
The non-condensable gas 60 is a gas mainly containing a combustible gas that is usually contained in the pyrolysis gas 45.

  Next, a recovery process is performed. The recovery step is a step of recovering the condensate 50.

Specifically, among the condensate 50 and the non-condensable gas 60 generated by the air-cooled condenser (cooler) 12, the condensate 50 is sent to the condensate tank 15A via the condensate recovery line 25, It is collected in the condensate tank 15A (step S106).
The condensate 50 collected in the condensate tank 15A is discarded as the waste liquid 50 via the waste liquid discharge line 33 (step S107).

  Of the condensate 50 and the non-condensable gas 60 generated by the air-cooled condenser (cooler) 12, the non-condensable gas 60 is sent to the secondary combustion furnace 13 via the non-condensable gas distribution line 22.

Next, a secondary combustion process is performed. The secondary combustion process is a process of burning the non-condensable gas 60 in the secondary combustion furnace 13.
Specifically, non-condensable gas 60 and combustion air 63 are introduced into the secondary combustion furnace 13 through the air supply line 32. Moreover, the inside of the secondary combustion furnace 13 is heated to 900 ° C. or more, for example. Thereby, in the secondary combustion furnace 13, the noncondensable gas 60 is combusted (step S108).
The reason why the interior of the secondary combustion furnace 13 is heated to, for example, 900 ° C. or more is to suppress the formation of hardly decomposable organic substances such as dioxins when the non-condensable gas 60 is burned. .

  When the non-condensable gas 60 is burned in the secondary combustion furnace 13, a secondary combustion processing gas 65 is generated. The secondary combustion processing gas 65 is a gas mainly containing carbon dioxide, water and the like. The secondary combustion processing gas 65 is discharged from the secondary combustion furnace 13, and after radioactive waste gas is adsorbed by a filter (not shown) or the like, it is released into the atmosphere (step S109).

<Effect of the first embodiment>
In the thermal decomposition apparatus 1A of the present invention, the entire amount of the pyrolysis gas 45 generated in the pyrolysis furnace 11 is not combusted in the secondary combustion furnace 13 as in the prior art, but is generated in the pyrolysis furnace 11. Of the gas 45, only the non-condensable gas 60 that is the remainder after the condensate 50 is removed by the cooler 12 is burned in the secondary combustion furnace 13. That is, the pyrolysis apparatus 1A has a smaller amount of gas that is combusted in the secondary combustion furnace 13 as compared to the prior art in which the cooler 12 is not provided.

  By the way, the required air flow rate and equipment dimensions of the secondary combustion furnace 13 and a radioactive waste gas processing device such as a filter (not shown) arranged downstream of the secondary combustion furnace 13 are the same as those of the gas processed by the radioactive waste gas processing device. Designed from the quantity.

  According to the thermal decomposition apparatus 1A of the present invention, since the amount of radioactive waste gas processed by the secondary combustion furnace 13 and the radioactive waste gas processing apparatus such as a filter is small, the radioactive waste gas processing apparatus can be downsized. .

  Further, in the thermal decomposition apparatus 1A, the secondary combustion furnace 13 and the radioactive waste gas treatment apparatus such as a filter are disposed of as secondary radioactive waste when used. Specifically, the used radioactive waste gas processing apparatus is cut, separated, and stored.

  According to the thermal decomposition apparatus 1A of the present invention, since the radioactive waste gas treatment apparatus such as the secondary combustion furnace 13 and the filter can be downsized, it becomes easy to dispose of the used radioactive waste gas treatment apparatus.

(Second Embodiment)
FIG. 3 is a schematic view of a second embodiment of the solid organic radioactive waste pyrolysis apparatus of the present invention.
A solid organic radioactive waste pyrolysis apparatus 1B shown in FIG. 3 includes a pyrolysis furnace 11 that pyrolyzes the solid organic radioactive waste 40, and a cooler that cools the pyrolysis gas 45 discharged from the pyrolysis furnace 11. 12, a condensate tank 15 </ b> B that contains the condensate 50 recovered by the cooler 12 and separates and purifies the liquefied organic matter contained in the condensate 50, and a non-condensable gas 60 discharged from the cooler 12. The secondary combustion furnace 13 to be combusted, the condensate tank 15B and the secondary combustion furnace 13 are connected, and the liquefied organic matter separated and purified from the condensate 50 by the condensate tank 15B is supplied to the burner of the secondary combustion furnace 13. And a liquefied organic substance supply line 26.

  The solid organic radioactive waste pyrolysis apparatus 1B shown as the second embodiment in FIG. 3 is compared with the solid organic radioactive waste pyrolysis apparatus 1A shown as the first embodiment in FIG. The difference is that a condensate tank 15B is provided instead of the condensate tank 15A, and a liquefied organic substance supply line 26 is further provided.

  Therefore, the solid organic radioactive waste pyrolysis apparatus 1B shown as the second embodiment in FIG. 3 and the solid organic radioactive waste pyrolysis apparatus 1A shown as the first embodiment in FIG. The same members are denoted by the same reference numerals, and the description of the configuration and operation is omitted.

<Condensate tank>
The condensate tank 15B accommodates the condensate 50 collected from the cooler 12 and separates and purifies the liquefied organic matter contained in the condensate 50.

  Specifically, the condensate tank 15 </ b> B is connected to the condensate 50 discharge portion of the cooler 12 via the condensate recovery line 25 and accommodates the condensate 50 discharged from the cooler 12.

  In addition, the condensate tank 15B includes a liquefied organic substance discharge unit 36 for discharging the liquefied organic substance separated and purified from the condensate 50, and a waste liquid for discharging the remainder obtained by separating the liquefied organic substance from the condensate 50 as a waste liquid. A discharge unit 35.

The fact that the condensate tank 15B separates and purifies the liquefied organic matter from the condensate 50 will be described with reference to the drawings.
FIG. 4 is a schematic view for explaining a part of the second embodiment of the solid organic radioactive waste thermal decomposition apparatus of the present invention. Specifically, FIG. 4 is an enlarged schematic view showing the condensate tank 15B, the secondary combustion furnace 13, and the liquefied organic matter supply line 26 in the solid organic radioactive waste thermal decomposition apparatus 1B.

  As shown in FIG. 4, in the condensate tank 15 </ b> B, a condensate tank internal space 17 is formed in the condensate tank main body 16, and the condensate 50 is stored in the condensate tank internal space 17.

  When the condensate 50 is allowed to stand in the condensate tank internal space 17, it is usually separated into three layers. Specifically, the stationary condensate 50 is usually separated from the bottom into three layers: a layer made of sludge 51, a layer made of liquefied organic matter 52 such as oil, and a layer made of water 53.

  In the condensate tank 15 </ b> B, the liquefied organic matter discharge portion 36 for discharging the liquefied organic matter 52 from the condensate tank 15 </ b> B is provided on the side surface of the condensate tank body 16. Therefore, when the condensate 50 is separated from the bottom into three layers, a layer made of sludge 51, a layer made of liquefied organic matter 52 such as oil, and a layer made of water 53, the discharge portion 36 of liquefied organic matter 52 Is positioned in the layer made of the liquefied organic matter 52, only the liquefied organic matter 52 can be discharged from the condensate tank 15B via the liquefied organic matter discharge portion 36.

  Thus, since the condensate tank 15B can discharge only the liquefied organic matter 52 from the condensate 50, the condensate tank 15B is a device for separating and purifying the liquefied organic matter 52 from the condensate 50. .

  The liquefied organic matter 52 discharged from the condensate tank 15B via the liquefied organic matter discharge unit 36 is supplied to the burner 14 of the secondary combustion furnace 13 via the liquefied organic matter supply line 26. In the secondary combustion furnace 13, the liquefied organic matter 52 is used as fuel for the burner 14.

  On the other hand, the remainder from which the liquefied organic matter 52 is separated from the condensate 50 is usually a mixture of sludge 51 and water 53. The mixture of the sludge 51 and the water 53 is discarded as waste liquid through a waste liquid discharge line 33 connected to the waste liquid discharge portion 35.

<Liquid organic substance supply line>
The liquefied organic substance supply line 26 connects the condensate tank 15B and the secondary combustion furnace 13, and supplies the liquefied organic substance separated and purified from the condensate 50 in the condensate tank 15B to the burner of the secondary combustion furnace 13. is there.
Specifically, one end of the liquefied organic substance supply line 26 is connected to the liquefied organic substance discharge section 36 of the condensate tank 15B, and the other end is connected to the liquefied organic substance introduction section (not shown) of the secondary combustion furnace 13. .
The liquefied organic matter 52 discharged from the condensate tank 15B via the liquefied organic matter discharge unit 36 is supplied to the burner 14 of the secondary combustion furnace 13 via the liquefied organic matter supply line 26. The liquefied organic substance 52 is used as fuel for the burner 14 of the secondary combustion furnace 13.

<Action>
With reference to FIGS. 3-5, the effect | action of the thermal decomposition apparatus 1B shown as 2nd Embodiment is demonstrated. FIG. 5 is an example of a flow of a thermal decomposition process using the second embodiment of the solid organic radioactive waste thermal decomposition apparatus of the present invention. Hereinafter, the operation when the cooler 12 is an air-cooled condenser will be described.

  The flow of the thermal decomposition process using the solid organic radioactive waste thermal decomposition apparatus 1B shown in FIG. 5 is the same as the flow of the thermal decomposition process using the solid organic radioactive waste thermal decomposition apparatus 1A shown in FIG. Steps S101 to S105 are the same. Therefore, in the flow of the thermal decomposition process using the solid organic radioactive waste thermal decomposition apparatus 1B shown in FIG. 5, the thermal decomposition process using the solid organic radioactive waste thermal decomposition apparatus 1A shown in FIG. The same processes as those in the flow are denoted by the same reference numerals, and the description of the configuration and operation is omitted.

  First, steps S101 to S105 are performed in the same manner as in the thermal decomposition process using the solid organic radioactive waste thermal decomposition apparatus 1A shown in FIG.

  In step S105, the pyrolysis gas 45 cooled in the air-cooled condenser 12 is partially liquefied or solidified to generate a condensate 50, and the remainder becomes a gaseous noncondensable gas 60.

  Next, of the condensate 50 and the non-condensable gas 60 generated by the air-cooled condenser (cooler) 12, the condensate 50 is sent to the condensate tank 15B via the condensate recovery line 25, and the condensate It is collected in the tank 15B (step S206).

  Furthermore, a liquefied organic substance separation purification process is performed. The liquefied organic matter separation and purification step is a step of separating and purifying the liquefied organic matter 52 contained in the condensate 50.

  In the liquefied organic matter separation and purification step, first, the condensate 50 is allowed to stand. When the condensate 50 is allowed to stand in the condensate tank space 17 of the condensate tank 15B, it is usually separated into three layers. The settled condensate 50 is usually separated from the bottom into three layers: a layer made of sludge 51, a layer made of liquefied organic matter 52 such as oil, and a layer made of water 53.

In the liquefied organic matter separation and purification step, secondly, only the liquefied organic matter 52 is separated from the condensate 50 that has been allowed to stand.
For example, when the condensate 50 is separated into three layers, a layer made of sludge 51, a layer made of liquefied organic matter 52 such as oil, and a layer made of water 53, the discharge portion 36 of liquefied organic matter is removed from liquefied organic matter 52. When positioned in the layer, when the liquefied organic substance 52 in the layer made of the liquefied organic substance 52 is sucked using a pump or the like (not shown), only the liquefied organic substance 52 is separated from the condensate 50 (step S207). By this step S207, the liquefied organic matter 52 in the condensate 50 is separated and purified from the condensate 50.

  When the liquefied organic matter 52 is separated from the condensate 50 in step S207, the remainder of the condensate 50 is usually a mixture of sludge 51 and water 53.

  The mixture of the sludge 51 and the water 53 is discarded as waste liquid through the waste liquid discharge line 33 connected to the waste liquid discharge section 35 (step S208).

  Next, a liquefied organic substance supply step is performed. The liquefied organic substance supply step is a step of supplying the separated and purified liquefied organic matter 52 to the secondary combustion furnace 13 as fuel for the burner 14 of the secondary combustion furnace 13.

  In the liquefied organic substance supply step, first, the liquefied organic substance 52 separated from the condensate 50 in step S207 is supplied to the burner 14 of the secondary combustion furnace 13 via the liquefied organic substance supply line 26. In the liquefied organic substance supply step, secondly, in the secondary combustion furnace 13, the liquefied organic substance 52 is used as fuel for the burner 14 of the secondary combustion furnace 13 and burned (step S209).

  Further, among the condensate 50 and the non-condensable gas 60 generated by the air-cooled condenser (cooler) 12 in step S105, the non-condensable gas 60 is heat using the thermal decomposition apparatus 1A shown in FIG. Steps S108 and S109 are performed in the same manner as the flow of the decomposition process.

  That is, the non-condensable gas 60 is combusted in the secondary combustion furnace 13 (step S108), and the secondary combustion processing gas 65 generated in the secondary combustion furnace 13 is discharged from the secondary combustion furnace 13 and is not shown in the figure. The waste gas is treated with a filter or the like and released into the atmosphere (step S109).

<Effects of Second Embodiment>
In the solid organic radioactive waste pyrolysis apparatus 1B of the present invention, the heat generated in the pyrolysis furnace 11 as in the prior art, as in the solid organic radioactive waste pyrolysis apparatus 1A shown as the first embodiment. The entire amount of the cracked gas 45 is not combusted in the secondary combustion furnace 13, but is the non-condensed that is the remainder after the condensate 50 is removed by the cooler 12 in the pyrolysis gas 45 generated in the pyrolysis furnace 11. Only the property gas 60 is burned in the secondary combustion furnace 13. That is, the pyrolysis apparatus 1B has a smaller amount of gas that is combusted in the secondary combustion furnace 13 as compared with the prior art in which the cooler 12 is not provided.

  According to the solid organic radioactive waste pyrolysis apparatus 1B of the present invention, since the amount of radioactive waste gas processed by the secondary combustion furnace 13 and the radioactive waste gas processing apparatus such as a filter is small, the radioactive waste gas processing apparatus It can be downsized.

  According to the thermal decomposition apparatus 1B for solid organic radioactive waste of the present invention, the radioactive waste gas treatment apparatus such as the secondary combustion furnace 13 and the filter can be downsized. Processing becomes easy.

  Furthermore, in the solid organic radioactive waste thermal decomposition apparatus 1 </ b> B, the condensate 50 generated by the air-cooled condenser (cooler) 12 is separated into a liquefied organic substance 52 and a waste liquid composed of components other than the liquefied organic substance 52. . And the liquefied organic substance 52 is used as a fuel of the burner 14 of the secondary combustion furnace 13, and the waste liquid which consists of components other than the liquefied organic substance 52 is discarded.

Thus, according to the solid organic radioactive waste thermal decomposition apparatus 1B of the present invention, since the liquefied organic matter 52 separated from the condensate 50 is reused as fuel, resources can be effectively utilized.
In addition, according to the solid organic radioactive waste thermal decomposition apparatus 1B of the present invention, the remainder from which the liquefied organic matter 52 is separated from the condensate 50 becomes waste liquid, so the amount of waste liquid is reduced and it is environmentally friendly.

  In the description of the operation of the first and second embodiments, the case where the cooler 12 is an air-cooled condenser has been described. However, the cooler 12 of the present invention can use a cooler other than the air-cooled condenser as long as the pyrolysis gas 45 can be cooled.

  In the description of the second embodiment, when the liquefied organic matter discharge portion 36 of the condensate tank 15B is located in a layer made of the liquefied organic matter 52, the liquefied organic matter 52 is sucked to separate the liquefied organic matter 52. explained.

  However, in the second embodiment of the present invention, a plurality of liquefied organic matter discharge portions 36 of the condensate tank 15B are provided in the height direction in the condensate tank 15B, and the liquefied organic matter discharged to the liquefied organic matter supply line 26 is discharged. By making the part 36 selectable, the discharge of the liquefied organic matter may be facilitated regardless of the position of the layer made of the liquefied organic matter 52 in the condensate tank 15B.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1, 1A, 1B Pyrolysis device (Pyrolysis device for solid organic radioactive waste)
2 Pyrolysis device (conventional pyrolysis device)
11 Pyrolysis furnace 12 Air-cooled condenser (cooler)
13 Secondary combustion furnace 14 Burner 15, 15A, 15B Condensate tank 16 Condensate tank body 17 Condensate tank inner space 21 Pyrolysis gas distribution line 22 Non-condensable gas distribution line 23 Secondary combustion treatment gas discharge line 25 Condensate Recovery line 26 Liquefied organic substance supply line 32 Air supply line 33 Waste liquid discharge line 35 Waste liquid discharge part 36 Liquefied organic substance discharge part 40 Solid organic radioactive waste 40A Solid organic waste 45 Pyrolysis gas 50 Condensate (waste liquid)
51 Sludge 52 Oil (Liquefied organic matter)
53 Water 60 Noncondensable gas 63 Combustion air 65 Secondary combustion treatment gas 71 Pyrolysis gas distribution line 73 Secondary combustion treatment gas discharge line 75 Residue recovery line 80 Carbide-containing residue 81 Ash 85 Secondary combustion treatment gas 86 Oxidation decomposition Gas 91 Pyrolysis treatment 92 Oxidation decomposition treatment

Claims (4)

A pyrolysis furnace that pyrolyzes solid organic radioactive waste in an oxygen-free atmosphere to produce a combustible pyrolysis gas;
A cooler that cools the pyrolysis gas discharged from the pyrolysis furnace and separates it into a condensate and a non-condensable gas;
A condensate tank containing condensate recovered from the cooler;
A secondary combustion furnace for burning the non-condensable gas discharged from the cooler;
A thermal decomposition apparatus for solid organic radioactive waste, comprising: The condensate tank accommodates the condensate recovered from the cooler and separates and purifies liquefied organic matter contained in the condensate,
The apparatus further comprises a liquefied organic substance supply line that connects the condensate tank and the secondary combustion furnace and supplies the liquefied organic substance separated and purified from the condensate in the condensate tank to a burner of the secondary combustion furnace. The thermal decomposition apparatus for solid organic radioactive waste according to claim 1. A pyrolysis process in which solid organic radioactive waste is pyrolyzed in an oxygen-free atmosphere to generate a combustible pyrolysis gas;
A cooling separation step of cooling the pyrolysis gas to separate it into a condensate and a non-condensable gas;
A recovery step of recovering the condensate;
A secondary combustion step of burning the non-condensable gas in a secondary combustion furnace;
A method for thermally decomposing solid organic radioactive waste, comprising: A liquefied organic matter separation and purification step for separating and purifying liquefied organic matter contained in the condensate;
A liquefied organic matter supplying step of supplying the separated and purified liquefied organic matter to the secondary combustion furnace as fuel for the burner of the secondary combustion furnace;
The method for thermal decomposition of solid organic radioactive waste according to claim 3, further comprising:

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