JP2000346561A - Apparatus and method for heat treating waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve thermal decomposition efficiency and to reduce the amount of a gaseous product included in a solid-like product after decomposing by providing a means for supplying an inert gas to a waste to be treated for heating and decomposing a matter to be treated by a heater in a passage. SOLUTION: A matter Fa1 to be treated introduced from a dumping hopper 1 into a casing 3 through a dumping side valve 2 is moved by a screw 4. The matter Fa1 is heated by a heater 3a of the casing 3, decomposed into a gas Pg of a gaseous decomposed product, and a residue Fa3 of a solid-like decomposed product, and the residue Fa3 is discharged from an outlet 3b of the casing 3 to a discharge hopper 5. A gas supply port 12 is covered with a cover so that the residue Fa3 filling from above may not enter the interior, and connected to a gas supply means 13 for supplying an inert gas Ps into the heater 3a. The means 13 supplies the gas Ps from the port 12 and allows it to rise in the hopper 5 and pass through the casing 3, and then the gas is exhausted from a gas exhaust port 9, and recovered to a gas recovery unit 13a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a waste plastic,
The present invention relates to a waste heat treatment apparatus and a waste heat treatment method in which an object to be treated, such as waste tires, is heated while moving in a passage and decomposed into gaseous decomposition products and solid decomposition products.

[0002]

2. Description of the Related Art As a waste heat treatment apparatus for heating waste such as waste plastics and waste tires to decompose them into gaseous decomposition products and solid decomposition products, for example, JP-A-9-2
A rotary kiln as disclosed in Japanese Patent No. 17988 is known. The rotary kiln supplies an object to be processed into a heating furnace and heats the object while rotating the heating furnace. In this rotary kiln, for example, when a chlorine-containing polymer resin such as a vinyl chloride resin is supplied as an object to be processed into a heating furnace, chlorine in the resin is removed from the resin as gaseous hydrogen chloride. You. Conventionally, in a waste heat treatment apparatus such as a rotary kiln, a gaseous decomposition product (evolved gas) and a solid decomposition product (residue) generated from an object to be processed are flowed together to an outlet of a heating furnace and discharged from the heating furnace. After that, the generated gas and the residue are separated.

[0003]

However, in the conventional waste heat treatment apparatus, since the generated gas and the residue flow together to the outlet of the heating furnace, both the high-concentration generated gas and the residue are heated. Since the residue is discharged downstream from the furnace, when the residue is taken out of the apparatus, a part of the generated gas adsorbed and held between the residues is taken out together with the residue. Further, when the residue is cooled, a part of the generated gas is re-adsorbed to the residue. For this reason, a large amount of generated gas is contained in the residue taken out of the apparatus, or the generated gas causes a strong odor of the residue.Therefore, post-treatment of the residue such as gas purging, depressurization, or heating is necessary. turn into.

[0004] The present invention has been made in view of such problems, and greatly improves the efficiency of thermal decomposition, and reduces the amount of gaseous decomposition products contained in solid decomposition products after pyrolysis. It is an object of the present invention to provide a waste heat treatment apparatus and a waste heat treatment method that require less after-treatment for solid decomposition products taken out of the apparatus.

[0005]

Means for Solving the Problems To solve the above-mentioned problems, the invention according to claim 1 moves an object to be processed from a charging side to a discharge side in a passage, and at the same time, heats the object by a heating unit in the passage. A waste heat treatment apparatus for heating the waste gas to decompose it into a gaseous decomposition product and a solid decomposition product, wherein gas supply means for supplying an inert gas that is inert to the object to be processed into the passage is provided. Means of provision are employed. This waste heat treatment apparatus includes gas supply means for supplying an inert gas that is inert to the object to be processed into the heating passage, so that the inert gas is supplied into the heating passage. The partial pressure of the gaseous decomposition product in the heating passage is reduced, and the thermal decomposition of the object is promoted.

According to a second aspect of the present invention, in the waste heat treatment apparatus of the first aspect, a means having a gas outlet for discharging gaseous decomposition products is provided in the middle of the heating section. . Since this waste heat treatment apparatus has a gas outlet in the middle of the heating passage, gaseous decomposition products are discharged from the middle of the heating passage, and the amount of gaseous decomposition products flowing downstream from the heating passage is reduced. Therefore, the possibility that the gaseous decomposition product is re-adsorbed to the solid decomposition product after heating is reduced.

[0007] The invention according to claim 3 is the invention according to claim 1 or 2.
In the waste heat treatment apparatus of (1), means for supplying an inert gas from the discharge side of the gas discharge port in a direction opposite to the moving direction of the object to be processed is adopted. In this waste heat treatment apparatus, an inert gas is supplied from a gas discharge port located in the middle of a heating passage from a discharge side of the apparatus in a direction opposite to a moving direction of the object to be processed, and is not counterflowed to the object to be processed. The active gas flows and comes into contact. For this reason, the to-be-processed material comes into contact with the inert gas having a lower component concentration of the gaseous decomposition product as it flows to the discharge side, and the thermal decomposition is further promoted.

According to a fourth aspect of the present invention, an object to be processed is moved from a charging side to a discharge side in a passage, and the object to be processed is heated by a heating portion in the passage to form a solid decomposition product and a solid decomposition. A waste heat treatment apparatus that decomposes into solid products, a descending section that lowers solid decomposition products, and an inert gas that is inert to the solid decomposition products is supplied upward from below the descending section. Means provided with a gas supply means. In this waste treatment apparatus, the inert gas flows upward in contact with the solid decomposition product in the descending section and comes into contact with the solid decomposition product. The gaseous decomposition products adsorbed and held by the decomposition products are efficiently removed. In addition, since the gaseous decomposition products adsorbed and held by the solid decomposition products are pushed upward while the inert gas rises due to the temperature gradient, the gaseous decomposition products hardly exist below.

According to a fifth aspect of the present invention, in the waste heat treatment apparatus of any one of the first to fourth aspects, means for using steam as an inert gas is employed. In this waste heat treatment apparatus, since steam is used as an inert gas, it is possible to effectively desorb and separate gaseous decomposition products from solid decomposition products.

According to a sixth aspect of the present invention, there is provided a waste heat treatment method for moving an object to be processed in an enclosed space while heating the object to decompose the object into a gaseous decomposition product and a solid decomposition product. Means for supplying an inert gas which is inert to the object to be processed to the space in contact with the object to be heated so as to reduce the partial pressure of the gaseous decomposition product in the space. Is done. In this waste heat treatment method, the partial pressure of the gaseous decomposition products is reduced by supplying an inert gas that is inert to the object to be heated to the object to be heated. Thermal decomposition is promoted.

According to a seventh aspect of the present invention, there is provided a waste heat treatment method for moving an object to be processed in an enclosed space while heating the object to decompose the object into a gaseous decomposition product and a solid decomposition product. In this case, means for flowing an inert gas, which is inert to the object to be processed, in countercurrent to the object to be heated is adopted. In this waste heat treatment apparatus, an inert gas is caused to flow in the counter-current to the object to be processed, so that the object to be processed comes into contact with the inert gas having a lower component concentration of the gaseous decomposition product as it moves, and Decomposition is further promoted.

The invention according to claim 8 is a waste heat treatment method in which an object to be processed is moved while being heated in an enclosed space, and the object to be processed is decomposed into a gaseous decomposition product and a solid decomposition product. In this case, means for flowing an inert gas, which is inert to the solid decomposition product, into the solid decomposition product in an upward flow is employed. In this waste heat treatment method, the inert gas flows upward in the solid decomposition product, so that the inert gas comes into efficient contact with the entire solid decomposition product and the solid decomposition product The inert gas is removed from the gaseous decomposition product adsorbed and held by the substance and is pushed upward to efficiently remove the gaseous decomposition product from the solid decomposition product.

According to a ninth aspect of the present invention, in the waste heat treatment method of any one of the sixth to eighth aspects, the inert gas is
Means using steam is employed. In this waste heat treatment method, since steam is used as an inert gas, it is possible to effectively desorb and separate gaseous decomposition products from solid decomposition products.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. In the present embodiment, the present invention is applied to a heat treatment apparatus using a screw feeder. This waste heat treatment apparatus has an input hopper 1
Is heated by the heating unit 3a of the casing 3 while being moved by the screw 4 into the casing 3 through the charging side valve 2 through the loading side valve 2.
a1 is decomposed into an evolved gas Pg which is a gaseous decomposition product and a residue Fa3 which is a solid decomposition product, and the residue Fa3 is discharged from the outlet 3b of the casing 3 to the discharge hopper 5.

The waste input as the object to be treated Fa1 is, for example, various such as waste plastic and waste tires.
When a chlorine-containing polymer resin such as a vinyl chloride resin is charged as the object to be treated Fa1, chlorine is converted into gaseous hydrogen chloride in the generated gas and removed from the resin. Further, when the waste tire is charged as the object to be treated Fa1, oil and sulfur components which become liquid at normal temperature are removed from the waste tire as the generated gas Pg to generate a residue Fa3.

The casing 3 is formed in a substantially cylindrical shape with one end closed, and a driving device 6 for rotating the internal screw 4 is provided on the outer end face on the entrance side. The screw 4 is formed in a substantially spiral shape, and gives an axial force to the workpiece Fa1 and the residue Fa3 (hereinafter collectively referred to as a workpiece / residue Fa2) by rotating to move to the discharge side. It is configured to be. Further, a part of the outer peripheral surface of the casing 3 is surrounded by the outer jacket 7, whereby a heat medium passage 8 is formed between the casing 3 and the outer jacket 7. External jacket 7
In order to pass the heat medium He through the heat medium passage 8 inside,
A heat medium supply port 7a is provided at an upper portion of the peripheral surface on the side of the discharge hopper 5, and a heat medium outlet 7b is provided at a lower portion of the peripheral surface of the input hopper 1 side. The heating portion 3a of the casing 3 is a heating passage having an outer peripheral surface facing the heat medium passage 8, and transfers heat heated by the heat medium He on the outer peripheral surface to the processing object / residue Fa2 flowing inside. It is configured to heat.

The casing 3 is provided with a gas outlet 9 in the middle of the heating section 3a for recovering the generated gas Pg thermally decomposed and removed from the workpiece Fa1 flowing inside. The gas discharge port 9 extends from the starting point P1 of the heating section toward the traveling direction of the workpiece Fa1 to about 3 mm of the entire length M of the heating section.
At a position of 0 to 90%, the tubular member is provided by welding to the upper part of the peripheral surface of the heating unit 3a.

The discharge hopper 5 is connected to the outlet 3b of the casing 3.
Is configured to flow the heated residue Fa3 discharged from the discharge port to the discharge-side valve 10 installed at the lower end. Also,
The discharge hopper 5 is provided with a plurality of baffle plates 11. Each baffle plate 11 is arranged in multiple stages with the inside direction of the discharge hopper 5 inclined downward, and one end is welded to the inner peripheral surface of the discharge hopper 5. Thus, the residue Fa3 decomposed by heating in the heating unit 3a flows down each baffle plate 11 one by one. In addition, the discharge hopper 5 is formed such that the descent length N of the residue Fa3 to the discharge side valve 10 is about 10% or more of M of the entire length of the heating unit 3a. Also, the discharge hopper 5
The gas supply port 12 is provided on the peripheral surface of the discharge hopper 5 immediately above the discharge side valve 10. This gas supply port 12
Is covered with a cover so that the residue Fa3 descending from above does not enter the inside, and is connected to gas supply means 13 for supplying the inert gas Ps into the heating section 3a.

The gas supply means 13 supplies the inert gas Ps with
The gas is supplied from the gas supply port 12, is raised in the discharge hopper 5, passes through the casing 3, and then is discharged from the gas discharge port 9 and collected in the gas recovery unit 13a.

The inert gas Ps used here is the object Fa to be treated.
1 and the residue Fa3 does not adsorb or substantially does not impart any harmful properties to the residue Fa3 even if adsorbed or mixed, and the residue after pyrolysis is substantially mixed even with the generated gas Pg It is inactive and does not impart any harmful properties to Fa3. Further, the inert gas Ps
Shall not seriously affect the separation and recovery even if mixed with the generated gas Pg. As such an inert gas Ps, for example, nitrogen or water vapor is used.
Can be used depending on the characteristics of For example, when water vapor is used as the inert gas Ps, the generated gas Pg is easily desorbed from the residue Fa3 more effectively than nitrogen, and furthermore,
When recovering the generated gas Pg component, water vapor (inert gas P
s) can be easily separated from the generated gas Pg by condensing s), and the generated gas Pg can be easily concentrated. Also,
The inert gas Ps is often supplied at a lower temperature than the atmosphere in the heating unit 3a.

In the waste heat treatment apparatus configured as described above, when the processing object Fa1 input from the input hopper 1 is heated by the heating unit 3a in the casing 3, the processing object Fa
1 to generate a generated gas Pg. Since the inert gas Ps is supplied from the gas supply unit 13 into the casing 3, the partial pressure of the generated gas Pg in the heating unit 3a is reduced, and the heat treatment and decomposition of the workpiece Fa1 is promoted. You. At this time, the inert gas Ps is supplied to the discharge hopper 5
, The inert gas Ps flows from the outlet 3b of the casing 3 toward the inlet, and flows counter-currently to the object-to-be-processed / residue Fa2, that is, the object-to-be-processed / residue Fa2 being heated.
The inert gas Ps flows in the direction opposite to. For this reason, the workpiece / residue Fa2 being heated comes into contact with the fluid having a low concentration of the generated gas Pg component contained in the inert gas Ps as it moves toward the outlet 3b,
The processed object / residue Fa2, which has been thermally decomposed to some extent, is further easily decomposed. Most of the generated gas Pg generated by the efficient thermal decomposition is removed from the residue Fa3,
The gas is discharged together with the inert gas Ps from the gas discharge port 9 provided in the middle of the heating unit 3a, and is recovered by the gas recovery unit 13a.

In this embodiment, the generated gas Pg is pushed back to the charging side by the inert gas Ps from the discharge hopper 5 side and is discharged from the gas discharge port 9 in the middle of the heating unit 3a. The generated gas Pg flowing to the hopper 5 side can be greatly reduced. The gas outlet 9 is positioned about 30 to 90% of the entire length M of the heating unit from the starting point P1 of the heating unit because the gas to be treated is discharged after the object Fa1 is sufficiently heated and pyrolysis proceeds. Further, a distance in which the object to be treated / residue Fa2 is brought into contact with the inert gas Ps in a countercurrent direction is secured, and the partial pressure of the generated gas Pg is as low as possible up to the outlet 3b of the casing 3. Residue F
This is because a sufficient time is required for the decomposition process of a3.

That is, the object to be treated Fa1 and the residue Fa
3 comes into contact with an atmosphere having a lower concentration of components of the generated gas Pg as it moves to the discharge side, so that the processing object F
The thermal decomposition of a1 is further promoted and the residue Fa3
The generated gas Pg component held and adsorbed in between becomes easy to be separated, thereby greatly reducing the amount of generated gas Pg contained in the residue Fa3.

The heated residue Fa3 flowing out of the casing 3 flows into the discharge hopper 5. In the discharge hopper 5, while descending one by one on the plurality of baffle plates 11,
The residue Fa3 flows to the lower discharge valve 10. The inert gas Ps is supplied from the gas supply port 12 below the discharge hopper 5, and the inert gas Ps rises and flows into the casing 3, whereby the inert gas Ps is added to the heated residue Fa3. Will flow upward and come into contact. By contacting the residue Fa3 descending by gravity in an upward flow, the generated gas in which the inert gas Ps efficiently contacts the entire residue Fa3 and is adsorbed and held between the surface of the residue Fa3 or the particles thereof. Remove Pg,
The generated gas Pg is pushed upward together with the inert gas Ps. In particular, when the temperature of the inert gas Ps is lower than that of the generated gas Pg flowing from the casing 3, the generated gas Pg is raised while being heated by the temperature gradient while the inert gas Ps is being heated by the temperature gradient. Will be pushed back. Therefore, the generated gas Pg hardly exists below the discharge hopper 5, and
The generated gas Pg in the residue Fa3 that has fallen is almost removed. The residue Fa in the discharge hopper 5
The reason why the falling length N of No. 3 is formed so as to be about 10% or more of the entire length M of the heating portion is to secure a sufficient distance for the inert gas Ps to contact the residue Fa3 and the upward flow.

Then, the dropped residue Fa3 is discharged from the discharge side valve 10 and taken out. As described above, the generated gas Pg is hardly taken out together with the residue Fa3, and since most of the generated gas Pg of the residue Fa3 is removed, the residue Fa3 is removed.
3 has almost no foul odor, gas purge, decompression,
Alternatively, there is little need to perform post-processing such as reheating.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the present invention is applied to an externally heated rotary kiln. In this rotary kiln, an object Fa1 to be charged into the inner cylinder 20 from the charging hopper 1 via the charging-side valve 2 is transferred to the inner cylinder 2.
Heating while rotating 0, the generated gas Pg component is gasified and removed from the processing object Fa1, and the residue Fa3 after heating is heated.
Is discharged to the discharge hopper 21.

An insertion pipe 2 is provided below the input valve 2.
2 is connected so that the object Fa1 flows into the rotating inner cylinder 20 via the insertion pipe 22.
The inner cylinder 20 includes fixed casings 23 and 24 and an outer cylinder 25.
Are fixed to the outer cylinder 25 and are configured to rotate together with the outer cylinder 25 by a driving device (not shown). Then, the inner cylinder 20 is rotated to remove the internal workpiece / residue Fa2 from the residue Fa3.
To the discharge side. A heat medium passage 26 is formed on the outer peripheral side of the inner cylinder 20, and the heat medium He supplied from the heat medium supply port 27 of the fixed casing 23 flows to the heat medium discharge port 28 of the fixed casing 24. Thus, the processing object Fa1 in the inner cylinder 20 is heated and thermally decomposed.

A gas discharge port 29 is provided in the middle of the inner cylinder 20 which is a heating passage. In this case, a gas discharge pipe 30 is provided to penetrate from the outside on the discharge hopper 21 side. The gas discharge pipe 30 is inserted from the outlet side of the inner cylinder 20, and is arranged such that the length of the portion inserted into the inner cylinder 20 is about 70 to 100% of the entire length of the inner cylinder 20. Has been established.

The discharge hopper 21 does not include the baffle plate 11 as shown in the first embodiment, and is configured to drop the residue Fa3 flowing from the inner cylinder 20 to the discharge side valve 10. Further, similarly to the first embodiment, a gas supply port 12 is provided below the discharge hopper 21, and
Thus, the inert gas Ps is supplied from the gas supply means 13. Then, the supplied inert gas Ps rises in the discharge hopper 21 and is supplied into the inner cylinder 20.

In this embodiment, similarly to the first embodiment, the generated gas Pg is pushed back from the discharge hopper 21 side to the charging side by the inert gas Ps, and
Since the gas is discharged from the gas discharge port 9 inside, the generated gas Pg component flowing from the inner cylinder 20 to the discharge hopper 21 side can be significantly reduced.

In addition, by flowing the inert gas Ps in the inner cylinder 20 in a countercurrent flow to the processing object / residue Fa2, the processing object Fa1 can be efficiently thermally decomposed. Then, in the discharge hopper 21, the inert gas Ps flows in an upward flow to contact the descent of the residue Fa3 after heating, and contacts the residue Fa3.
The generated gas Pg adsorbed on the gaseous fuel No. 3 and the generated gas Pg held between the residues Fa3 are removed, and are pushed upward together with the inert gas Ps. Thereby, the discharge hopper 21
, The generated gas Pg almost disappears, and the generated gas Pg adsorbed and held by the dropped residue Fa3 is almost completely removed. Therefore, the gas Pg is discharged from the discharge side valve 10 and taken out. Residue Fa3 contains little generated gas Pg.

[0032]

As described above, according to the present invention, the following effects can be obtained. Since the waste heat treatment apparatus according to claim 1 supplies an inert gas that is inert to the object to be processed into the heating passage, the partial pressure of the gaseous decomposition product in the heating passage is reduced, The efficiency of thermal decomposition of the object can be improved. For this reason, the amount of gaseous decomposition products contained in the solid decomposition products after thermal decomposition can be reduced.

In the waste heat treatment apparatus according to the second aspect, the gas discharge port is provided in the middle of the heating passage, and the gaseous decomposition product is discharged from the middle of the heating passage. Gaseous decomposition products are less likely to be re-adsorbed to the solid decomposition products after heating. For this reason, the amount of gaseous decomposition products contained in the solid decomposition products taken out of the apparatus can be further reduced.

In the waste heat treatment apparatus according to the third aspect, since the inert gas is supplied from the discharge side of the apparatus toward the inside of the heating passage, the inert gas flows countercurrently to the object to be treated and comes into contact therewith. As a result, the gaseous decomposition products held in the object to be treated are easily separated, and the thermal decomposition of the object to be treated is promoted. Further, since the object to be treated comes into contact with the atmosphere having a lower component concentration of the gaseous decomposition product as it moves toward the discharge side, the thermal decomposition is further promoted. Thus, the amount of gaseous decomposition products contained in the solid decomposition products taken out of the apparatus can be significantly reduced.

In the waste heat treatment apparatus according to the fourth aspect, in the descending portion, the inert gas flows upward and comes into contact with the falling solid decomposition product, so that the inert gas is solid decomposed. The entire product can be efficiently contacted, and the gaseous decomposition products held on the surface of the solid decomposition products or between the particles can be efficiently removed. Moreover,
Since the inert gas pushes the gaseous decomposition products upward while rising due to the temperature gradient, almost no gaseous decomposition products are present below. Then, by taking out the solid decomposition products from below, almost no gaseous decomposition products are taken out of the apparatus together with the solid decomposition products. This virtually eliminates the need for post-treatment to solid decomposition products, such as gas purge, depressurization, or heating.

In the waste heat treatment apparatus according to the fifth aspect, since steam is used as an inert gas, gaseous decomposition products can be effectively desorbed and separated from solid decomposition products. When further recovering gaseous decomposition products,
By condensing steam, gaseous decomposition products can be easily concentrated.

In the waste heat treatment method according to the sixth aspect, by supplying an inert gas to the object being heated,
Since the partial pressure of the gaseous decomposition product is reduced, the efficiency of the thermal decomposition of the object to be treated can be improved, and the amount of the gaseous decomposition product contained in the solid decomposition product after the thermal decomposition can be reduced. .

In the waste heat treatment method according to the seventh aspect, since the inert gas is caused to flow in the counter-current to the object to be treated, the object to be treated comes into contact with the atmosphere having a lower concentration of components of the gaseous decomposition products as it moves. And thermal decomposition is promoted. Thus, the amount of gaseous decomposition products contained in the solid decomposition products taken out of the apparatus can be significantly reduced.

In the waste heat treatment method according to the eighth aspect, the inert gas is caused to flow upward in the solid decomposition product, so that the inert gas can efficiently contact the entire solid decomposition product. At the same time, the gaseous decomposition products adsorbed and held between the solid decomposition products are removed and pushed upward, so that the gaseous decomposition products can be efficiently removed from the solid decomposition products. This virtually eliminates the need for post-treatment to solid decomposition products, such as gas purge, depressurization, or heating.

In the waste heat treatment method according to the ninth aspect, since steam is used as an inert gas, gaseous decomposition products can be effectively desorbed and separated from solid decomposition products. When recovering the decomposition products, the gaseous decomposition products can be easily concentrated by condensing the water vapor.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the overall schematic configuration of a first embodiment of the device of the present invention.

FIG. 2 is a longitudinal sectional view showing the overall schematic configuration of a second embodiment of the device of the present invention.

[Explanation of symbols]

 Fa1 treatment object Fa2 treatment object and residue Fa3 residue (solid decomposition product) Pg generated gas (gaseous decomposition product) Ps inert gas He heating medium 3 passage 20 inner cylinder (passage, heating unit) 3a heating unit 5, 21 discharge hopper (falling part) 9 gas outlet 13 gas supply means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K061 GA05 GA10 KA02 KA16 KA27 KA28 4D004 AA07 BA03 CA24 CB09 CB45 CC01 CC03 4H012 HA03 HA05 4K061 AA08 BA00 BA07 CA02 CA08 CA23 EA03 FA02 FA13

Claims (9)

[Claims] 1. An object to be processed is moved from a charging side to a discharge side in a passage, and the object to be processed is heated by a heating unit in the passage to be converted into a gaseous decomposition product and a solid decomposition product. What is claimed is: 1. A waste heat treatment apparatus for decomposing, comprising: gas supply means for supplying an inert gas inert to the object to be treated into the passage. 2. The waste heat treatment apparatus according to claim 1, further comprising a gas outlet for discharging the gaseous decomposition products in the middle of the heating section. 3. The method according to claim 1, wherein the gas supply unit supplies the inert gas from the discharge side of the gas discharge port in a direction opposite to a moving direction of the workpiece. 3. The waste heat treatment apparatus according to 2. 4. An object to be processed is moved from a charging side to a discharge side in a passage, and the object to be processed is heated by a heating unit in the passage to be converted into a gaseous decomposition product and a solid decomposition product. A waste heat treatment apparatus for decomposing, comprising: a descending portion for descending the solid decomposition product; and an inert gas inert to the solid decomposition product being supplied upward from below the descending portion. A waste heat treatment apparatus comprising: gas supply means. 5. The waste heat treatment apparatus according to claim 1, wherein steam is used as the inert gas. 6. A waste heat treatment method in which an object to be processed is moved while being heated in an enclosed space, and the object to be processed is decomposed into a gaseous decomposition product and a solid decomposition product. An inert gas that is inert to the object to be processed is supplied to a space in contact with the object to be processed so as to reduce the partial pressure of the gaseous decomposition product in the space. Waste heat treatment method. 7. A waste heat treatment method for moving an object to be processed in an enclosed space while heating the object to decompose the object into a gaseous decomposition product and a solid decomposition product. A waste heat treatment method, wherein an inert gas that is inert to the object to be processed is caused to flow in countercurrent to the object to be processed. 8. A waste heat treatment method in which an object to be processed is moved while being heated in an enclosed space, and the object to be processed is decomposed into a gaseous decomposition product and a solid decomposition product. A waste heat treatment method comprising flowing an inert gas, which is inert to the solid decomposition product, in an upward flow through the solid decomposition product. 9. The waste heat treatment method according to claim 6, wherein steam is used as the inert gas.