AU714634B2

AU714634B2 - Noxious component removal process and noxious component removal agent therefor

Info

Publication number: AU714634B2
Application number: AU56329/98A
Authority: AU
Inventors: Haruhisa Ishigaki; Yoshiyuki Kashiwagi; Noboyuki Yoshioka
Original assignee: Meidensha Corp; Meidensha Electric Manufacturing Co Ltd
Current assignee: Meidensha Corp
Priority date: 1997-02-24
Filing date: 1998-02-24
Publication date: 2000-01-06
Anticipated expiration: 2018-02-24
Also published as: DK0860183T3; CN1197685A; AU5632998A; ES2186931T3; EP0860183A2; KR100341551B1; NO980758L; DE69809310D1; EP0860183A3; KR19980071609A; NO316905B1; EP0860183B1; CN1095687C; ATE227598T1; DE69809310T2; NO980758D0; MY121329A

Abstract

A process for removing chlorine and/or sulfur from a waste containing chlorine and/or sulfur which chlorine is a source of dioxin. The process comprises the following steps in the sequence set forth: (a) mixing the waste and a chlorine and sulfur removal agent to form a mixture, the chlorine and sulfur removal agent containing an alkali metal compound; and (b) heating the mixture to thermally decompose the waste to generate chlorine-containing substance and/or a sulfur-containing substance, in which the chlorine-containing substance and/or the sulfur-containing substance allow to contact and react with the chlorine and sulfur removal agent thereby to form harmless chloride and/or sulfite. <IMAGE>

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: *c 9** NOXIOUS COMPONENT REMOVAL PROCESS AND NOXIOUS COMPONENT REMOVAL AGENT THEREFOR The following statement is a full description of this invention, including the best method of performing it known to us: GH REF: P19354-I:DGC:RK r NOXIOUS COMPONENT REMOVAL PROCESS AND NOXIOUS COMPONENT REMOVAL AGENT THEREFOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in a process for removing a noxious component (such as chlorine and/or sulfur) from a material (referred to as "treatable material") containing chlorine and or sulfur, such as urban waste or trash and industrial waste, and to improvements in a noxious component removal agent to be used in the process, and more particularly to a technique in which the noxious component removal agent is reacted with noxious component-containing gas (hydrogen chloride, chlorine gas and/or sulfur oxide gas) generated upon thermal treatment of the trash and waste to form harmless gas and compounds.

2. Description of the Prior Art *Recently waste such as urban waste or trash are increasing in its amount year by year so that its treatment is becoming problematic. Such urban waste includes waste or trash 20 from general homes and offices and therefore is mainly constituted of combustible waste. This combustible waste includes a variety of chemical substances (for example, plastic) containing a large e amount of polyvinyl chloride, and a variety of materials (for example, paper used in offices) containing a large amount of chlorine ."25 components such as chlorine-containing bleaching agent.

In general, incineration has been usually employed for treating such waste. However, when the waste or treatable material containing chlorine components is incinerated, chlorine-containing gas such as hydrogen chloride gas and chlorine gas is generated thereby raising problems of environmental pollution and deterioration of incinerating facility under the action of the chlorine-containing gas. For the purpose of suppressing generation of such chlorine-containing gas, it has been carried out to incinerate -2- The waste or treatable material upon adding thereto a chlorine removal agent such as slaked lime, calcium carbonate or the like. Additionally, it has been also known that after the treatable material cast in an incinerator is subjected to an incineration treatment, emitted gas undergoes a variety of purification treatments as occasion demands, for example, is introduced into a bag filter so as to be reacted with slaked lime thus preventing noxious chlorine-containing gas from being emitted to the patmospheric air.

00 0 S. As discussed above, in case of incineration of the 0 waste or treatable material, the chlorine-containing 0000 se 15 substances such as chlorine and other chlorine compounds are problematic, in which chlorine-containing gas generated in the course of incineration damages the incinerator 0000 .o itself and corrodes steam pipes and further leads to .600 problems of producing dioxin which is virulently poisonous.

o0 20 Accordingly, chlorine-containing gas has been usually reacted with slaked lime or the like in the bag filter S: thereby being prevented from being emitted to the atmospheric air. Such measures can be expected to obtain a certain effect under treatment of burnt gas so that chlorine-containing gas can be prevented from being dispersed to the atmospheric air. However, it is difficult to completely remove chlorine-containing substances by such measures because chlorine-containing substances remain in a Rresidue formed after incineration of the treatable 3 material. This forms part of cause of generating dioxin.

Even by the measure of adding slaked line or calcium carbonate during the incineration, chlorine-containing gas has not been able to be sufficiently prevented from its generation.

Further, it has been proposed that alkali material is sprayed into the incinerator in which the treatable material is incinerated. In this proposition, however, chlorine-containing gas which has been once generated and filled in the incinerator is treated, which is similar to the above measure and therefore renders it impossible to completely remove chlorine-containing gas.

Furthermore, it has been also proposed that incineration of the treatable material is accomplished upon 15 adding thereto alkali material containing calcium such as lime (CaCO 3 slaked line (Ca(OH) 2 or the like, or that Sox is passed through a filter filled with the alkali material to remove Sox. Reactions made in these propositions are as follows: 20 In case of treatment of chlorine-containing gas (HC1): CaCO3 2HC1 CaC1 2 H20 CO 2 Ca(OH)2 2HC1 CaC1 2 2H 2 0 In case of treatment of sulfur oxide containing gas

(SO

2 CaCO 3 CaO CO 2 CaO SO 2 1/202 CaSO, Ca(OH) 2 CaO H 2 0 CaO SO 2 1/202 CaSO 4 4 Besides, it has also been proposed to cause the treatable material to be subjected to thermal decomposition or dry distillation in place of incineration, thereby reducing the volume of the treatable material and carbonizing the treatable material. Additionally, it is known to spray alkali material such as slaked lime into a furnace; however, no sufficient effect of removing chlorine-containing gas can be expected because the alkali material is brought into contact with chlorine-containing gas which has been once generated and filled in the Sfurnace.

In view of the above, it has been eagerly desired to hasten establishment of techniques for sufficiently removing chlorine-containing gas or sufficiently preventing chlorine-containing gas forms generation even upon thermal a treatment of the treatable material, which chlorinea containing gas forms part of cause of production of dioxin a..

which is known as being virulently poisonous for human body.

A first aspect of the present invention resides in a process for removing at least one of chlorine and sulfur from a treatable material containing at least one of chlorine and sulfur, comprising the following steps in the sequence set forth: mixing the treatable material and a chlorine and sulfur removal agent to form a mixture, said chlorine and sulfur removal agent containing at least one compound selected from the group consisting of a sodium compound and a potassium compound, said sodium compound being other than sodium carbonate; and S en heating said mixture in a low oxygen concentration

)SO

atmosphere to thermally decompose the treatable material to generate at least one of a chlorine-containing substance 15 and a sulfur-containing substance and cause at least one of

V,

i the chlorine-containing substance and the sulfur-containing substance to contact and react with said chlorine and sulfur removal agent to form at least one of harmless chloride and sulfite.

-6- A second aspect of the present invention resides in a noxious component removal agent to be used in a process for removing noxious component from a treatable material containing the noxious component, the chlorine removal agent containing a sodium compound other than sodium carbonate and/or potassium compound, the noxious removal agent being contactable and able to react with a noxious component-containing substance generated from the treatable material upon heating the treatable material in a low oxygen concentration atmosphere, so as to form a harmless compound.

A third aspect of the present invention resides in a chlorine and sulfur removal agent to be used in a process for removing at least one of chlorine and sulfur from a *54* treatable material containing at least one of chlorine and 4*44** sulfur, the chlorine and sulfur removal agent containing an sodium compound other than sodium carbonate and/or a potassium compound, the chlorine and sulfur removal agent -7being contactable and able to react with at least one of a chlorine-containing substance and a sulfur-containing substance generated from the treatable material upon heating the treatable material, so as to form at least one of harmless chloride and sulfite.

A fourth aspect of the present invention resides in an apparatus for removing at least one of chlorine and sulfur from a treatable material containing at least one of chlorine and sulfur, said apparatus comprising: a device for mixing the treatable material and a chlorine and sulfur removal agent to form a mixture, the chlorine and sulfur removal agent containing a sodium compound V.060 other than sodium carbonate and/or potassium compound; moo• 15 a furnace into which the mixture of the treatable material and the chlorine and sulfur removal agent 0 0 V a a is supplied, the furnace being adapted to form therein a low oxygen concentration atmosphere; and a heating S.device for heating the mixture in the low oxygen device for heating the mixture in the low oxygen 8 concentration atmosphere in the furnace to thermally decompose the treatable material so as to accomplish dry distillation of the treatable material, in which the mixture generates at least one of a chlorine-containing substance and a sulfur-containing substance and cause at least one of the chlorine-containing substance and the sulfur-containing substance to contact and react with the chlorine and sulfur removal agent to form at least one of harmless chloride and sulfite.

6 .9 a Ii a Oa 0 -9- BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of a chlorine and sulfur removal system for carrying out the fifth embodiment of the noxious component removal process according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION 10 According to one aspect of the present invention, a process for removing noxious component (such as chlorine and/or sulfur) from a treatable material (such as urban awaste or trash, or industrial waste) containing the noxious component, comprises the following steps in the sequence set .o forth: mixing the treatable material and a noxious component (chloride and/or sulfur) removal agent to form a mixture, the noxious removal agent containing an alkali metal compound; and heating the mixture to thermally S: 193541.doc decompose the treatable material to generate a noxious component (chlorine and/or sulfur) containing substance and cause the noxious component-containing substance to contact and react with the noxious component removal agent to form a harmless compound.

Examples of the harmful component (chlorine and/or sulfur) removal agent to be used in the above noxious component removal process are: alkali metal hydrogen carbonate, alkali metal carbonate and the like, such as sodium hydrogen carbonate (NaHCO 3 sodium sesqui carbonate (Na 2

CO

3 NaHCO 3 2H 2 0), and natural soda (containing NA 2 CO NaHCO 3 2H 2 0); 11 alkali metal hydroxide such as sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH), rubidium hydroxide (RbOH), and cesium hydroxide (CsOH); and alkali metal carbonate and alkali metal hydrogen carbonate such as potassium carbonate (K 2 CO0), potassium hydrogen carbonate (KHCO,), and potassium sodium carbonate (KNaCO 6H 2 0).

It will be understood that the above-listed compounds are used singly or in combination as the noxious component removal agent. In other words, the noxious component removal agent contains at least one of sodium hydrogen carbonate, sodium carbonate, sodium sesqui carbonate, natural soda, sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide (RbOH), and cesium hydroxide (CsOH), potassium carbonate, potassium hydrogen carbonate, and potassium sodium carbonate, and the like.

The noxious component removal agent to be used in the form of mass, plate, porous body, particle (including power, granule, or mixture of powder and granule), solution (aqueous solution, or other solutions), or suspension. These forms are used singly or in combination.

'use The amount of the noxious component removal agent to be So used is usually within a range of from 0.05 to 10 by weight relative to the treatable material at a starting time which is before a time at 25 which the treatable material is mixed with the noxious component removal agent. However, in case the treatable material including substances or compounds containing a large amount of chlorine component, such as polyvinyl chloride, polyvinylidene chloride, other chlorine-containing synthetic resins and/or chlorinecontaining rubbers, the amount of the noxious component removal agent to be used is within a range of from 10 to 17 weight relative to the treatable material at the starting time. The amount of the noxious component removal agent may be selected to be larger than the chemical equivalent of chlorine-containing substance or gas (a substance or gas containing chlorine) generated from the treatable material upon heating, regardless of the weight of the treatable material. Otherwise, the amount of the noxious component removal agent may be selected to suppress the emission levels of chlorinecontaining gases below permissible emission standards. Also in case the treatable material includes substances or compounds containing a large amount of sulfur component, the amount of the noxious component is selected similarly to the above.

The noxious component removal agent is mixed with the treatable material and heated at a thermal decomposition temperature ranging from 200 to 1000 °C in a low oxygen concentration atmosphere. In other words, mixing of the noxious component removal agent and the treatable material is made before heating for thermally decomposing the treatable material, i.e., before the temperature of the treatable material rises to a level at which the thermal decomposition of the treatable material occurs. At ew the decomposition temperature, chlorine compounds, sulfur compounds and substances containing chlorine and/or sulfur are 20 thermally decomposed. The low oxygen concentration atmosphere means an atmosphere in which the concentration of oxygen is low, which can be accomplished by closing the inlet and outlet of a 9* thermal treatment furnace or tank such as a heating furnace, upon casting the mixture of the treatable material and the noxious o 25 component removal agent into the furnace. It will be understood that the low oxygen concentration atmosphere corresponds to a condition in which atmospheric air remains within the furnace whose inlet and outlet have been closed. In other words, the low oxygen concentration atmosphere corresponds to a condition in which the mixture is put in the furnace which is substantially sealed so as to prevent fresh air from being supplied into the furnace, in which a pressure in the furnace leaks out of the furnace. Accordingly, the low oxygen concentration atmosphere does not require a complete 13 closing or sealing state of the furnace and includes also a condition in which the side of the inlet of the furnace is closed with the treatable material itself, in which a gas pressure within the furnace is raised under heating so that supply of air from the outside of the furnace is hardly made. The low oxygen concentration atmosphere may be a thermal decomposition atmosphere in which the treatable material thermally decomposes to generate so-called thermal decomposition gas of the treatable material. Thus, the low oxygen concentration atmosphere accomplishes dry distillation of the treatable material.

It will be understood that the noxious component removal agent is basically mixed with the treatable material upon being cast or sprayed onto the treatable material in the furnace. The noxious component removal agent may be additionally cast or sprayed onto the mixture of the treatable material and the noxious component removal agent in the furnace.

As a result of the above heating in the low oxygen concentration atmosphere, substantially no gas component of chlorine-containing compounds (compounds containing chlorine) 20 and/or sulfur-containing compounds (compounds containing sulfur) remain in emitted gas from the furnace, and therefore a post- ~treatment (such as a heating treatment or secondary burning) for the emitted gas can be made as occasion demands. It is a matter of course that the emitted gas may be discharged to the atmospheric 25 air as it is. o.o.

S

While the noxious component removal agent has been described as being mixed with the treatable material before heating or thermal decomposition of the treatable material, it will be understood that noxious component removal agent may be also effective for removing chlorine even upon contacting with dry distillation gas or emitted gas (gas generated under dry distillation of the treatable material) discharged from the furnace after heating or thermal decomposition of the treatable material. It will be also 14 understood that the noxious component removal material may be supplied or sprayed onto the treatable material which is thermally decomposing. Furthermore, it will be appreciated that the noxious component removal agent according to the present invention may be used to be brought into contact with chlorine-containing substance and/or sulfur-containing substance which are in any step of a noxious component removal process other than the process according to the present invention, for the purpose of removing chlorine from noxious gas or a material containing chlorine.

Here, a first embodiment of the noxious component or chlorine removal process according to the present invention will be discussed. In this embodiment, the noxious component or chlorine removal agent contains alkali metal hydrogen carbonate and/or alkali metal carbonate, at least one of sodium hydrogen carbonate (NaHCO,), sodium carbonate (Na 2 sodium sesqui carbonate (Na 2

CO

3 NaHCO, 2H 2 natural soda (containing NaCO 3 NaHC0 3 In this instance, sodium hydrogen carbonate (NaHCO 3 is used as the chlorine removal agent, in which the sodium hydrogen 20 carbonate is mixed with the treatable material and heated thereby bringing about the following reaction with hydrogen chloride (HC1) which is a major chlorine-containing compound contained in gases generated from the treatable material upon heating.

NaHC0 3 HC1 NaCl H 2 0 C02 o 25 According to this reaction, if Na and CO components exist in the reaction system, chlorine reacts with Na to form NaCl which is a part of a residue formed upon heating the treatable material, and .additionally water (H 2 0) and gas (C0 2 are formed. As a result, no chlorine-containing gas is generated and emitted from the furnace, realizing that the emitted gas and the residue are rendered harmless.

It will be understood that chlorine-containing compound or gas is a source for producing dioxin which is virulently poisonous.

According to one embodiment of the present invention, prior to a thermal treatment is applied to the treatable material containing chlorine-containing substance which will generate chlorine-containing gas upon heating, alkali metal carbonate and/or alkali metal hydrogen carbonate are added to and mixed with the treatable material as the chlorine removal agent thereby form the mixture. By heating this mixture in the low oxygen concentration atmosphere, the chlorine-containing substance is thermally decomposed at a predetermined temperature thereby generating harmful chlorine-containing gas. This chlorine-containing gas immediately reacts with the chlorine removal agent thus to form harmless chloride.

Hereinafter, experiments for carrying out the chlorine removal process according to this embodiment will be discussed, in which comparison in experimental result is made between Examples (according to this embodiment) and Comparative Examples (not within the scope of the present 9SS* S invention).

S. V S•Experiment 1 The chlorine removal process of this embodiment was carded out by using as the treatable material, polyvinylidene chloride which contained a large amount of 25 chlorine components. As shown in Table 1, 20g of the chlorine removal agent (sodium hydrogen carbonate) was added to 4g of the treatable material to form a mixture to be V.

heated, in Example 1-1. No chlorine removal agent was added to 4g of the treatable material in Comparative Example 1-1.

A chlorine removal agent (slaked or hydrated lime) which was

SB..

,oe not within the scope of the present invention was add in an amount of 20g to 4g of the treatable material to form a mixture to be heated, in Comparative Example 1-2. A chlorine removable agent (calcium carbonate) which was not within the scope of the present invention was added in an amount of 20g to 4g of the treatable material to form a mixture to be heated, in Comparative Example 1-3.

The chlorine removal agent was in the form of powder S:193541.doc 16 having an average particle size of 100 g m, in all Example and Comparative Examples.

More specifically, in the experiment for each Example or Comparative Example, 4 g of the treatable material was put into a tank or furnace, and then 20 g of the chlorine removal agent was added to and mixed with the treatable material in the tank to form the above-mentioned mixture, except for Comparative Example 1-1.

Then, the tank was tightly sealed so that the inside the tank was isolated from the outside air or atmospheric air in order that the mixture was subjected to dry distillation upon heating. The thus sealed tank was stepwise heated with a heating coil, in which heating was made at eight temperature steps of 250 300 °C, 350 400 0C, 450 0C, 500 550 0C, 600 In this heating process, the temperature at each of the eight steps was kept for 5 minutes, in which a concentration of hydrogen chloride gas in the tank was measured at each temperature rising time (at which the temperature was rising from one temperature step to the next temperature step) and at each temperature keeping time (at which the temperature at each temperature step was keeping). The 20 temperature rising time is indicated as "Rising time" while the temperature keeping time is indicated as "Keeping time" in Table 3.

The tank was provided with a gas discharge pipe through which gas and pressure generated in the tank upon heating was discharged out of the tank. The measurement of the hydrogen chloride gas 25 concentration was accomplished by using a detector tube according m °to JIS (Japanese Industrial Standard) K0804, in which the detector tube was inserted into the gas discharge pipe to measure .the hydrogen chloride gas concentration. Results of the hydrogen chloride gas concentration measurement were shown in Table. 3. It is to be noted that ten times of the above experiment were repeated to obtain ten actual measured values of the hydrogen gas concentration for each Example and Comparative Example, in which the measured value (shown in Table 3) for each Example indicates 17 the highest value in the measured values while the measured value (shown in Table 3) for each Comparative Example indicates the lowest value in the measured values. Additionally, "ND" in Table 3 indicates the fact that no hydrogen chloride gas was detected in any of 10 times hydrogen chloride gas concentration measurements to obtain the ten actual measured values. Further, manners of posttreatment for the chlorine removal agent were inspected and shown as "Post-treatment for chlorine removal agent" in Table 3.

Experiment 2 In this experiment, the treatable material was prepared by mixing polyvinylidene chloride with a simulated trash in order that the treatable material was similar to standard urban trash and in order to carry out the experiment under a further severe condition.

As shown in Table 2, 5g of sodium hydrogen carbonate was added as the chlorine removal agent to the treatable material which was prepared by mixing 1 g of polyvinylidene chloride to 20 g of the simulated trash thereby to form the mixture to be heated, in Example 1-2. Sodium hydrogen carbonate in an amount of 2.5 g was added as the chlorine removal agent to the treatable material which S 20 was prepared by mixing 0.5 g of polyvinylidene chloride to 20 g of the simulated trash thereby forming the mixture to be heated, in 00 Example 1-3. Sodium hydrogen carbonate in an amount of 0.5 g was added as the chlorine removal agent to the treatable material which was prepared by mixing 0.1 g of polyvinylidene chloride to 20 g of the 25 simulated trash thereby forming the mixture to be heated, in Example 1-4. Sodium hydrogen carbonate in an amount of 5 g was added as the chlorine removal agent to the treatable material which *005 .was prepared by mixing 20 cc of city water to 20 g of the simulated 00 trash thereby forming the mixture to be heated, in Example The above simulated trash similar to standard urban trash was prepared by mixing and crushing the following components:

M

U

18 by weight of plastic including polyethylene, polypropylene, polystyrene, and polyvinylidene chloride; by weight of paper including tissue paper, news paper, wrapping paper, paper box, and paper packing for drink; 20 by weight of cloth including rag; and by weight of garbage including used tea leaves.

In the experiment for each Example, the above-mentioned predetermined amount of the treatable material was put into the tank, and then the above-mentioned predetermined amount of the chlorine removal agent was added to and mixed with the treatable material in the tank to form the above-mentioned mixture. Then, the tank was tightly closed to maintain an air-tight seal so that the inside the tank was isolated from the outside air or atmospheric air.

Thereafter, the experiment was carried out similarly to that in Experiment 1 to obtain results (or measured values) shown in Table 3. Results (or measured values) of the hydrogen chloride gas concentration measurement were shown in Table 3.

As appreciated from the above, it has been revealed that the hydrogen carbonate or carbonate containing an alkali metal, serving as the chlorine removal agent, can convert noxious chlorine-containing gas into harmless chloride under a reaction in which the alkali metal reacts with chlorine to form chloride of alkali metal. A preliminary test (Comparative Example 1-1) was conducted in which polyvinylidene chloride containing a large amount of 25 chlorine component was used as the treatable material. As a result of this test, it was confirmed that a large amount of hydrogen chloride was generated as shown in the column of Comparative Example 1-1 in Table 3.

Subsequently, comparative tests (Comparative Examples 30 1-2 and 1-3) were conducted in which slaked lime and calcium carbonate were respectively used as the conventional chlorine removal agents. As a result, generation of hydrogen chloride could be suppressed to some extent; however, it was confirmed that such a 19 suppression effect due to the conventional chlorine removal agents was not sufficient and was required to be further improved.

In view of the above, as a result of a variety of investigations and considerations, the inventors had paid attention to hydrogen carbonate and carbonate containing alkali metal and selected sodium hydrogen carbonate as the chlorine removal agent, and conducted tests (Examples 1-1 to As a result of the tests, it has been revealed that generation of hydrogen chloride could be generally completely suppressed at any temperature regions, and that sodium hydrogen carbonate was very excellent as the chlorine removal agent.

Thus, the above reveals that if hydrogen carbonate and/or carbonate containing alkali metal (to be able to react with chloride) is added to the treatable material to form the mixture to be subjected to the thermal treatment, chlorine-containing gas generated from the treatable material can effectively dechlorinated and become harmless.

Hereinafter, discussion will be made depending upon the above experimental results shown in Table 3.

First in case that polyvinylidene chloride was used as the treatable material containing a large amount of chlorine component and that no chlorine removal agent was used as shown in Comparative Example 1-1, a large amount of hydrogen chloride gas was generated throughout a wide temperature region in the thermal 25 treatment or heating process. Generation of hydrogen chloride gas could be suppressed to some extent as compared with Comparative S° Example 1-1, in Comparative Examples 1-2 and 1-3 where slaked lime and calcium carbonate were added as the chlorine removal agent to the treatable material, respectively. However, it was 30 confirmed that such suppression for hydrogen chloride gas was o insufficient.

In contrast, in Example 1-1 where sodium hydrogen carbonate was added as the chlorine removal agent to the treatable material, no generation of hydrogen chloride gas could be detected throughout the whole temperature regions in the heating process, demonstrating that the sodium hydrogen carbonate was very excellent for the chloride removal agent. Additionally, also in Examples 1-3, 1-4 and 1-5 where various amounts of sodium hydrogen carbonate were added as the chlorine removal agent to the treatable material containing the simulated trash and polyvinylidene chloride, no generation of hydrogen chloride gas could be detected throughout the whole temperature regions in the heating process.

In case of Example 1-5 where sodium hydrogen carbonate was added as the chlorine removal agent to the treatable material containing the simulated trash and water, generation of hydrogen chloride gas could hardly be detected throughout the whole temperature regions although a slight amount of hydrogen chloride gas was detected to be generated at the temperature rising and keeping times at 450 0C and at the temperature rising time at 500 0C. This demonstrates that the effect of sodium hydrogen carbonate as the chlorine removal agent could hardly be affected in presence of water in the treatable material, and considerably high as compared with Comparative Example 1-2 where slaked lime was used as the chlorine removal agent.

In conclusion, it has been confirmed that addition of hydrogen carbonate and/or carbonate containing alkali metal (to be 25 able to react with chloride) to the treatable material in the thermal treatment or heating process can effectively accomplish dechlorination of chlorine-containing gas generated from the treatable material thereby causing the chlorine-containing gas to become harmless.

30 It is to be noted that experiments similar to the above were conducted heating the treatable material at a higher temperature condition over 600 0C, which exhibited similar experimental results to the above. The temperature for heating the mixture of the S 21 treatable material and the chlorine removal agent is preferably within a range of not higher than 1000 "C from the view point of the fact that a facility for carrying out the chlorine removal process of the present invention is required to be large-sized if the temperature is raised over 1000 "C.

Next, discussion will be made on mechanisms of reaction between hydrogen carbonate or carbonate containing alkali metal (sodium) and chlorine-containing gas, realizing unexpected results in which both emitted gas and residue are made harmless.

In case of using sodium hydrogen carbonate as the chlorine removal agent: When sodium hydrogen carbonate (NaHCO,) is added to the treatable material which is to generate hydrogen chloride (HC1), sodium hydrogen carbonate and hydrogen chloride react as follows: NaHCO, HC1 -4 NaC1 H 2 0 CO0 In the presence of water in reaction between sodium hydrogen carbonate and the treatable material which is to generate hydrogen chloride, reaction is made according to the following chemical equations: NaHCO, H 2 0 NaOH H 2 O H 2

CO,

NaOH H 2 CO, HC1 NaC1 H 2 0 CO2 In case of using sodium carbonate as the chlorine removal agent: When sodium hydrogen carbonate (Na 2

CO

3 is added to the 25 treatable material which is to generate hydrogen chloride (HC1), sodium hydrogen carbonate and hydrogen chloride as follows: Na2CO, 2HC1 2NaCl HO 2 CO2 In case of using sodium sesqui carbonate as the chlorine removal agent: 30 Sodium sesqui carbonate is represented by a chemical formula, Na 2 CO, NaHCO3 2H20 and can react with hydrogen chloride similarly to the cases of and thereby converting noxious hydrogen chloride into harmless chloride (NaC). Sodium sesqui carbonate naturally exists as and called "trona".

In the above experiments, the residue was left in the tank after the heating process had been completed. The residue was subjected to inspection, upon which it was detected that the residue did not contain noxious chlorine-containing gas component and contained harmless chloride or sodium chloride. The residue was put into water and stirred for 10 minutes, in which sodium chloride was dissolved in water while carbonized materials remained. It was also detected that the carbonized materials did not contain chlorinecontaining gas component.

Accordingly, chlorine-containing compound and chlorine component in the treatable material can be converted into sodium chloride (NaCl), water (H 2 0) and carbon dioxide gas and therefore hydrogen chloride forming part of a source of dioxin cannot be formed thereby realizing the unexpected result of making both emitted gas and residue harmless.

It will be appreciated that, in this embodiment, the substance containing carbonate containing an alkali metal, such as sodium carbonate, sodium hydrogen carbonate, sodium sesqui carbonate, natural soda (Na 2

CO

3 NaHCO 3 2HO 2 0) is used as the chlorine removal agent. Sodium carbonate can form monohydrate compound and decahydrate compound and is known as soda. Sodium sesqui carbonate naturally exists as trona.

~25 As will be understood, in the heating process in which the reactions according to the above chemical reactions are made, NaC1 is formed. NaC1 is a harmless chloride and can be effectively S-removed under a rinsing or dissolving treatment with water or the like. After the rinsing treatment, solid residual materials or 30 carbonized materials remain in the tank and reusable. Accordingly, the residual materials can be separated into respective materials which are different in characteristics by any separating means. The separated respective materials are dried and massed to be usable as fuel or the like. Additionally, liquid (such as water) used for the above rinsing treatment hardly contains no noxious substances and therefore can be discharged as it is to a river and the sea.

More specifically, the residue taken out from the tank contains harmless chloride or sodium chloride (NaC). In order to extract the carbonized materials, the residue is put into a water tank containing water, and stirred for a predetermined time thereby dissolving sodium chloride. Subsequently, solid materials in the water tank are taken out from the water tank and then are subjected to a centrifugal dehydration to separate water content from the solid materials. The thus dehydrated solid materials are dried and hardened into a mass. Water remaining in the water tank and the separated water content are drained through a separate draining and treatment means. It will be appreciated that carbon contents in the hardened mass can be used as fuel while inorganic contents in the hardened mass can be used as materials for glass and cement.

Further, as discussed above, the residue can be separated into respective materials which are different in characteristics by any separating means, upon which the separated respective materials are dried and massed to be effectively used as fuel or the like.

Next, a second embodiment of the noxious component or chlorine removal process according to the present invention will be discussed. In this embodiment, the noxious component or chlorine removal agent contains at least one alkali metal hydroxide, at o: 25 least one of sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH), rubidium hydroxide (RbOH), and cesium hydroxide (CsOH).

S-As an instance, sodium hydroxide (NaOH) is used as the chlorine removal agent, in which the sodium hydroxide is mixed with 30 the treatable material and heated thereby bringing about the following reaction with hydrogen chloride (HCl) which is a major chlorine-containing compound contained in gases generated from the treatable material upon heating: -24- NaOH HCl NaC1 H 2 0 According to this reaction, hydrogen chloride reacts with sodium hydroxide to form sodium chloride (NaCI) forming part of the residue and water (H20). As a result, no chlorine-containing gas is generated and emitted from the furnace, realizing that the emitted gas and the residue are rendered harmless. It will be understood that chlorinecontaining compound or gas is a source for producing dioxin which is virulently poisonous for human body.

According to this embodiment of the present invention, when a heating treatment is applied to the treatable material containing chlorine-containing substance which will generate chlorine-containing gas upon heating, alkali metal hydroxide is added to and mixed with the treatable material as the chlorine removal agent thereby form the mixture. By heating this mixture in the low oxygen concentration atmosphere, the chlorine-containing substance is thermally decomposed at a predetermined temperature thereby generating harmful chlorine-containing gas. This chlorine-containing gas immediately reacts with the chlorine removal agent thus to form harmless chloride.

Hereinafter, experiments for carrying out the chlorine removal process according to this embodiment will be e discussed, in which comparison in experimental result is 25 made between Examples (according to this embodiment) and Comparative Examples (not within the scope of the present invention).

The chlorine removal process of this experiment was carried out by using as the treatable material, 30 polyvinylidene chloride which contained a large amount of chlorine components. As shown in Table 4, 20 g of the chlorine removal agent (pulverized sodium hydroxide) was ~added to 4g of the treatable material to form a mixture to be heated, in Example 2-1. The chlorine removal agent (pulverized potassium hydroxide) in amount of 20g was added to 4g of the treatable material to form a mixture to be heated, in Example 2-2. No chlorine removal agent was added to ig and to 4g of the S:193541.doc

J

treatable material ,respectively, in Comparative Examples 2-1 and 2-2. A chlorine removal agent (slaked or hydrated lime) which was not within the scope of the present invention in an amount of 20 g was added to 4 g of the treatable material to form a mixture to be heated, in Comparative Example 2-3. A chlorine removable agent (calcium carbonate) which was not within the scope of the present invention in an amount of 20 g was added to 4 g of the treatable material to form a mixture to be heated, in Comparative Example 2-4. The chlorine removal agent was in the form of powder having an average particle size of 100 /tm, in all Example and Comparative Examples.

In the experiment for each Example or Comparative Example, the treatable material in the above-mentioned amount was put into a tank or furnace, and then 20 g of the chlorine removal agent was added to and mixed with the treatable material in the tank to form the above-mentioned mixture, except for Comparative Examples 2-1 and 2-2. Then, the tank was tightly sealed so that the inside the tank was isolated from the outside air or atmospheric air in order that the mixture was subjected to dry distillation upon heating. The thus sealed tank was stepwise heated with a heating coil, in which heating was made at eight temperature steps of 250 °C, 300 350 400 0C, 450 0C, 500 0C, 550 0C, 600 0C and 600 to 1000 0C. In this heating process, the temperature at each of the nine steps was kept for 5 minutes, in which a concentration of hydrogen 25 chloride gas in the tank was measured at each temperature rising time (at which the temperature was rising from one temperature step to the next temperature step) and at each temperature keeping time (at which the temperature at each temperature step was keeping). The temperature rising time is indicated as "Rising time" 30 while the temperature keeping time is indicated as "Keeping time" 0- Sin Table 4. The tank was provided with a gas discharge pipe through which gas and pressure generated in the tank upon heating was discharged out of the tank. The measurement of the hydrogen chloride gas concentration was accomplished by using a detector tube according to JIS (Japanese Industrial Standard) K0804, in which the detector tube was inserted into the gas discharge pipe to measure the hydrogen chloride gas concentration. Results of the hydrogen chloride gas concentration measurement were shown in Fig. 4. It is to be noted that ten times of the above experiment were repeated to obtain ten actual measured values of the hydrogen gas concentration for each Example and Comparative Example, in which the measured value (shown in Table 4) for each Example indicates the highest value in the measured values while the measured value (shown in Table 4) for each Comparative Example indicates the lowest value in the measured values. Additionally, "ND" in Table 4 indicates the fact that no hydrogen chloride gas was detected in any of 10 times hydrogen chloride gas concentration measurements to obtain the ten actual measured values. Further, manners of posttreatment for the chlorine removal agent were inspected and shown as "Post-treatment for chlorine removal agent" in Table 4.

As appreciated from the above, it has been revealed that the alkali metal hydroxide serving as the chlorine removal agent can effectively convert noxious chlorine-containing gas into harmless chloride under a reaction in which the alkali metal reacts with :chlorine to form chloride of alkali metal. Preliminary tests (Comparative Examples 2-1 and 2-2) were conducted in which polyvinylidene chloride containing a large amount of chlorine 25 component was used as the treatable material. As a result of these tests, it was confirmed that a large amount of hydrogen chloride was generated as shown in the column of Comparative Examples 2-1 and oo :2-2 in Table 4.

Subsequently, comparative tests (Comparative Examples 30 2-3 and 2-4) were conducted in which slaked lime and calcium °carbonate were respectively used as the conventional chlorine removal agents. As a result, generation of hydrogen chloride could be suppressed to some extent; however, it was confirmed that such a

L

27 suppression effect due to the conventional chlorine removal agents was not sufficient and was required to be further improved.

In view of the above, as a result of a variety of investigations and considerations, the inventors had paid attention to alkali metal hydroxide and selected potassium hydroxide as the chlorine removal agent, and conducted tests (Examples 2-1 and 2-2).

As a result of the tests, it has been revealed that generation of hydrogen chloride could be generally completely suppressed at any temperature regions, and that potassium hydroxide was very excellent as the chlorine removal agent. Thus, the above reveals that if alkali metal hydroxide is added to the treatable material to form the mixture to be subjected to the thermal treatment, chlorinecontaining gas generated from the treatable material can effectively dechlorinated and become harmless.

Here, discussion will be made depending upon the above experimental results shown in Table 4.

First in case of carrying out the thermal treatment of polyvinylidene chloride (the treatable material containing a large amount of chlorine component) using no chlorine removal agent as shown in Comparative Examples 2-1 and 2-2, a large amount of hydrogen chloride gas was generated throughout a wide temperature region in the thermal treatment or heating process.

Generation of hydrogen chloride gas could be suppressed to some extent as compared with Comparative Examples 2-1 and 2-2, in 25 Comparative Examples 2-3 and 2-4 where slaked lime and calcium carbonate were added as the chlorine removal agent to the treatable SS-material, respectively. However, it was confirmed that such suppression for hydrogen chloride gas was insufficient.

In contrast, in Examples 2-1 and 2-2 where 20 g of sodium S 30 hydroxide and 20 g of potassium hydroxide were added as the 5r chlorine removal agent respectively to the same treatable materials, a slight amount of hydrogen chloride was found to be generated at the rising times of 350 "C and 450 °C in Example 2-1 and at the 28 keeping time of 450 "C in Example 2-2; however, no hydrogen chloride gas generation was found throughout whole temperature regions of the thermal treatment or in heating process, thereby exhibiting good experimental results as compared with those of Comparative Examples 2-1 to 2-4. In conclusion, it has been confirmed that addition of alkali metal hydroxide (to be able to react with chloride) to the treatable material in the thermal treatment or heating process can effectively accomplish dechlorination of chlorine-containing gas generated from the treatable material thereby causing the chlorine-containing gas to become harmless.

It is to be noted that experiments similar to the above were conducted heating the treatable material at a higher temperature condition over 600 which exhibited similar experimental results to the above. The temperature for heating the mixture of the treatable material and the chlorine removal agent is preferably within a range of not higher than 1000 °C from the view point of the fact that a facility for carrying out the chlorine removal process of the present invention is required to be large-sized if the temperature is raised over 1000 "C.

Discussion will be made on mechanisms of reaction between alkali metal hydroxide and chlorine-containing gas, realizing unexpected results in which both emitted gas and residue are made harmless.

In case of using sodium hydroxide (NaOH) as the 25 chlorine removal agent: When sodium hydroxide is added to the treatable material S-which is to generate hydrogen chloride (HC1), sodium hydroxide reacts with hydrogen chloride to form harmless sodium chloride and water as follows: 30 NaOH HCl -*NaC1 HO In case of using potassium hydroxide (KOH) as the chlorine removal agent: a a.

When potassium hydroxide is added to the treatable material which is to generate hydrogen chloride (HC1), potassium hydroxide reacts with hydrogen chloride to form potassium chloride and water, as follows: KOH HC KC1 H 2 0 In the above experiments, the residue was left in the tank after the heating process had been completed. The residue was subjected to inspection, upon which it was detected that the residue did not contain noxious chlorine-containing gas component and contained harmless chloride (sodium chloride or potassium chloride).

The residue was put into water and stirred for 10 minutes, in which sodium or potassium chloride was dissolved in water while carbonized materials remained. It was also detected that the carbonized materials did not contain chlorine-containing gas component.

Accordingly, chlorine-containing compound and chlorine component in the treatable material can be converted into sodium or potassium chloride and water, and therefore hydrogen chloride forming part of a source of dioxin cannot be formed thereby realizing the unexpected results of making both emitted gas and residue harmless. It will be appreciated that the same results can be obtained even if at least one of other alkali metal hydroxides such as lithium hydroxide (LiOH), rubidium hydroxide (RbOH), and cesium hydroxide (CsOH) are used as the chlorine removal agent.

25 Thus, it will be understood that, in this embodiment, at least one alkali metal hydroxide, sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH), rubidium 9*99 hydroxide (RbOH), and/or cesium hydroxide (CsOH) is used as the chlorine removal agent.

30 As will be understood, in the heating process in which the reactions according to the above chemical reactions are made, NaCl and KC1 are formed. NaC1 and KC1 are harmless chlorides and can be effectively removed under a rinsing or dissolving treatment with water or the like. After the rinsing treatment, solid residual materials or carbonized materials remain in the tank and reusable.

Accordingly, the residual materials can be separated into respective materials which are different in characteristics by any separating means. The separated respective materials are dried and massed to be usable as fuel or the like. Additionally, liquid (such as water) used for the above rinsing treatment hardly contains no noxious substances and therefore can be discharged as it is to a river and the sea.

More specifically, the residue taken out from the tank contains harmless sodium chloride (NaCl) and potassium chloride (KC1). In order to extract the carbonized materials, the residue is put into a water tank containing water, and stirred for a predetermined time thereby dissolving sodium and potassium chlorides.

Subsequently, solid materials in the water tank are taken out from the water tank and then are subjected to a centrifugal dehydration to separate water content from the solid materials. The thus dehydrated solid materials are dried and massed. Water remaining in the water tank and the separated water content are drained through a separate draining and treatment means. It will be appreciated that carbon contents in the massed solid materials can be used as fuel while inorganic contents in the massed solid materials can be used as materials for glass and cement. Further, as discussed above, the residue can be separated into respective 25 materials which are different in characteristics by any separating means, upon which the separated respective materials are dried and massed to be effectively used as fuel or the like.

Next, a third embodiment of the noxious component or chlorine removal process according to the present invention will be :Ii 30 discussed. This embodiment is particularly applicable to the chlorine removal process for polyvinyl chloride, polyvinylidene chloride, a synthetic resin containing chlorine, a rubber containing chlorine and/or the like. In this embodiment, the noxious component chlorine oo 31 removal agent contains alkali metal hydrogen carbonate and/or alkali metal carbonate, at least one of sodium hydrogen carbonate, sodium carbonate, sodium sesqui carbonate, and natural soda. Additionally, polyvinyl chloride and polyvinylidene chloride are used as the treatable material in this embodiment.

As an instance, sodium hydrogen carbonate (NaHCO 3 is used as the chlorine removal agent, in which the sodium hydrogen carbonate is mixed with the treatable material and heated thereby bringing about the following reaction with hydrogen chloride (HC1) which is a major chlorine-containing compound contained in gases generated from the treatable material upon heating: NaHCO 3 HC1 NaC1 H 2 0 C02. According to this reaction, if Na and CO components exist in the reaction system, chlorine reacts with Na to form NaC1 which is a part of a residue formed upon heating the treatable material, and additionally water (HO20) and gas (C0 2 are formed. As a result, no chlorine-containing gas is generated and emitted from the furnace, realizing that the emitted gas and the residue are rendered harmless. It will be understood that chlorinecontaining compound or gas is a source for producing dioxin which is virulently poisonous.

According to this embodiment, when the heating r treatment is applied to the treatable material containing chlorinecontaining substance which will generate chlorine-containing gas upon heating, alkali metal carbonate and/or alkali metal hydrogen 25 carbonate are added to and mixed with the treatable material as the chlorine removal agent thereby form the mixture. By heating this mixture in the low oxygen concentration atmosphere, the chlorinecontaining substance is thermally decomposed at a predetermined temperature thereby generating harmful chlorine-containing gas.

30 This chlorine-containing gas immediately reacts with the chlorine removal agent thus to form harmless chloride.

Hereinafter, experiments for carrying out the chlorine removal process according to this embodiment will be discussed, in which comparison in experimental result is made between Examples (according to this embodiment) and Comparative Examples (not within the scope of the present invention).

The chlorine removal process of this experiment was carried out by using ,as the treatable material, polyvinyl chloride and polyvinylidene chloride which contained a large amount of chloride components. As shown in Table 5, 20 g of the chlorine removal agent (sodium hydrogen carbonate) was added to 4 g of the treatable material (polyvinyl chloride) to form a mixture to be heated, in Example 3-1. The chlorine removal agent (sodium hydrogen carbonate) in an amount of 20g was added to 4 g of the treatable material (polyvinylidene chloride) to form a mixture to be heated, in Example 3-2. No chlorine removal agent was added to 4g of the treatable material (polyvinylidene chloride) in Comparative Example 3-1. A chlorine removal agent (calcium carbonate) which was not within the scope of the present invention was add in an amount of 20 g to 4 g of the treatable material (polyvinylidene chloride) to form a mixture to be heated, in Comparative Example 3-2. A chlorine removable agent (slaked lime) which was not within the scope of the present invention was added in an amount of 20 g to S"4 g of the treatable material (polyvinylidene chloride) to form a S: mixture to be heated, in Comparative Example 3-3. The chlorine removal agent was in the form of powder having an average particle size of 100 gim, in all Example and Comparative Examples.

25 In the experiment for each Example or Comparative Example, 4 g of the treatable material was put into a tank or furnace, a.

and then 20 g of the chlorine removal agent was added to and mixed with the treatable material in the tank to form the above-mentioned mixture, except for Comparative Example 3-1. Then, the tank was a o 30 tightly sealed so that the inside the tank was isolated from the ea.* 5005 outside air or atmospheric air in order that the mixture was subjected to dry distillation upon heating. The thus sealed tank was stepwise heated with a heating coil, in which heating was made at 33 eight temperature steps of 250 C, 300 C6, 350 400 450 °C, 500 550 600 In this heating process, the temperature at each of the eight steps was kept for 5 minutes, in which a concentration of hydrogen chloride gas in the tank was measured at each temperature rising time (at which the temperature was rising from one temperature step to the next temperature step) and at each temperature keeping time (at which the temperature at each temperature step was keeping). The temperature rising time is indicated as "Rising time" while the temperature keeping time is indicated as "Keeping time" in Table 5. The tank was provided with a gas discharge pipe through which gas and pressure generated in the tank upon heating was discharged out of the tank. The measurement of the hydrogen chloride gas concentration was accomplished by using a detector tube according to JIS (Japanese Industrial Standard) K0804, in which the detector tube was inserted into the gas discharge pipe to measure the hydrogen chloride gas concentration. Results of the hydrogen chloride gas concentration measurement were shown in Table 5. It is to be noted that ten times of the above experiment were repeated to obtain ten actual measured values of the hydrogen gas concentration for each Example and Comparative Example, in which the measured value (shown in Table 5) for each Example indicates the highest value in the measured values while the measured value (shown in Table for each Comparative Example indicates the lowest value in the 25 measured values. Additionally, "ND" in Table 5 indicates the fact that no hydrogen chloride gas was detected in any of 10 times hydrogen chloride gas concentration measurements to obtain the ten actual measured values. Further, manners of post-treatment for the chlorine removal agent were inspected and shown as "Post- 30 treatment for chlorine removal agent" in Table 6 •As appreciated from the above, it has been revealed that the hydrogen carbonate or carbonate containing an alkali metal, serving as the chlorine removal agent, can convert noxious chlorine-containing gas into harmless chloride under a reaction in which the alkali metal reacts with chlorine to form chloride of alkali metal. A preliminary test (Comparative Example 3-1) was conducted in which polyvinylidene chloride containing a large amount of chlorine component was used as the treatable material. As a result of this test, it was confirmed that a large amount of hydrogen chloride was generated as shown in the column of Comparative Example 3-1 in Table Subsequently, comparative tests (Comparative Examples 1-2 and 1-3) were conducted in which calcium carbonate and slaked lime were respectively used as the conventional chlorine removal agents. As a result, generation of hydrogen chloride could be suppressed to some extent; however, it was confirmed that such a suppression effect due to the conventional chlorine removal agents was not sufficient and was required to be further improved.

As a result of the tests (Examples 3-1 and it has been revealed that generation of hydrogen chloride could be generally completely suppressed at any temperature regions, and that sodium hydrogen carbonate was very excellent as the chlorine removal agent.

Thus, the above discussion demonstrates that if hydrogen carbonate and/or carbonate containing alkali metal (to be able to react with chloride) is added to the treatable material to form the mixture to be subjected to the thermal treatment, chlorine-

S..

25 containing gas generated from the treatable material can effectively dechlorinated and become harmless.

Here, discussion will be made depending upon the above

OSSO

experimental results shown in Table First in case that polyvinylidene chloride was used as the

S..

30 treatable material containing a large amount of chlorine component O•gS and that no chlorine removal agent was used as shown in Comparative Example 3-1, a large amount of hydrogen chloride gas wr..

was generated throughout a wide temperature region in the thermal O0• •0 O treatment or heating process. Generation of hydrogen chloride gas could be suppressed to some extent as compared with Comparative Example 3-1, in Comparative Examples 3-2 and 3-3 where calcium carbonate and slaked lime acre added as the chlorine removal agent to the treatable material, respectively. However, it was confirmed that such suppression for hydrogen chloride gas was insufficient.

In contrast, in Example 3-2 where sodium hydrogen carbonate was added as the chlorine removal agent to the treatable material, no generation of hydrogen chloride gas could be detected throughout the whole temperature regions in the heating process, demonstrating that the sodium hydrogen carbonate was very excellent as the chloride removal agent. In Example 3-1 where sodium hydrogen carbonate was added as the chlorine removal agent to the other treatable material (polyvinyl chloride), generation of hydrogen chloride gas could be completely suppressed throughout the whole temperature regions in the heating process.

In conclusion, it has been confirmed that addition of hydrogen carbonate and/or carbonate containing alkali metal (to be able to react with chloride) to the treatable material containing polyvinyl chloride or the like in the thermal treatment or heating process can effectively 25 accomplish dechlorination of chlorine-containing gas generated from the treatable material thereby causing the .chlorine-containing gas to become harmless. It is to be noted that experiments similar to the above were conducted heating the treatable material at a higher temperature condition over 600 0 C, which exhibited similar experimental results to the above. The temperature for heating the mixture of the treatable material and the chlorine removal agent is preferably within a range of not higher than 1000 0

C

from the view point of the fact that a facility for carrying out the chlorine removal process of this embodiment of the present invention is required to be large-sized if the temperature is raised over 1000 0

C.

teIt will be understood that the same reactions as those in "the first embodiment are made when sodium hydrogen carbonate, S:193541.doc sodium carbonate or sodium sesqui carbonate reacts with hydrogen chloride generated from the treatable material (polyvinyl chloride or polyvinylidene chloride) to form harmless sodium chloride, water and carbon dioxide.

Accordingly, chlorine-containing compound and chlorine component in the treatable material can be converted into sodium chloride (NaC), water (HO 2 0) and carbon dioxide gas (CO 2 and therefore hydrogen chloride forming part of a source of dioxin cannot be formed thereby realizing the unexpected result of making both emitted gas and residue harmless.

20 It will be appreciated that, in this embodiment, sodium o.

carbonate, sodium hydrogen carbonate, and/or sodium sesqui carbonate, natural soda is used as the chlorine removal agent.

Sodium carbonate can form monohydrate compound and decahydrate compound and is known as soda. Sodium sesqui carbonate naturally exists as trona. As will be understood, in the heating process in which the reactions according to the above chemical reactions are made, NaC1 is formed. NaC1 is a harmless chloride and can be effectively removed under a rinsing or dissolving treatment with water or the like. After the rinsing treatment, solid 30 residual materials or carbonized materials remain in the tank and reusable. Accordingly, the residual materials can be separated into 'o respective materials which are different in characteristics by any separating means. The separated respective materials are dried and 37 massed to be usable as fuel or the like. Additionally, liquid (such as water) used for the above rinsing treatment hardly contains no noxious substances and therefore can be discharged as it is to a river and the sea.

Next, a fourth embodiment of the noxious component or chlorine removal process according to the present invention will be discussed. In this embodiment, the noxious component or chlorine removal agent contains alkali metal hydrogen carbonate and/or alkali metal carbonate, at least one of potassium hydrogen carbonate (KHCO,) and potassium carbonate (K 2 C,0 3 and used in the chlorine removal process for the treatable material which is polyvinyl chloride, polyvinylidene chloride, a synthetic resin containing chlorine, a rubber containing chlorine, and/or the like.

As an instance, sodium hydrogen carbonate (KHCO 3 is used as the chlorine removal agent, in which the sodium hydrogen carbonate is mixed with the treatable material and heated thereby bringing about the following reaction with hydrogen chloride (HC1) which is a major chlorine-containing compound contained in gases generated from the treatable material upon heating.

KHCO HC1 -KC1 H 2 0 CO 2 According to this reaction, if Na and CO components exist in the reaction system, chlorine reacts with Na to form NaC1 which is a part of a residue formed upon heating the treatable material, and additionally water (H20) and gas (C0 2 are formed. As a result, no chlorine-containing gas is generated and emitted from the furnace, realizing that the emitted gas and the residue are rendered harmless.

S.:.It will be understood that chlorine-containing compound or gas is a source for producing dioxin which is virulently poisonous.

According to this embodiment, when the heating 30 treatment is applied to the treatable material containing chlorinecontaining substance which will generate chlorine-containing gas upon heating, alkali metal carbonate and/or alkali metal hydrogen carbonate are added to and mixed with the treatable material as the i chlorine removal agent thereby to form the mixture. By heating this mixture in the low oxygen concentration atmosphere, the chlorinecontaining substance is thermally decomposed at a predetermined temperature thereby generating harmful chlorine-containing gas.

This chlorine-containing gas immediately reacts with the chlorine removal agent thus to form harmless chloride.

The chlorine removal process of this embodiment was carried out by using, as the treatable material, polyvinylidene chloride or the simulated (standard) trash which contained a large amount of chlorine components. The simulated trash was the same as that used in the experiments for the first embodiment. As shown in Table 6, 10 g of the chlorine removal agent (pulverized potassium hydrogen carbonate) was added to 4 g of the treatable material (polyvinylidene chloride) to form a mixture to be heated, in Example 4-1. The chlorine removal agent (pulverized potassium hydrogen carbonate) in an amount of 10 g was added to 4 g of the treatable r°""material (the simulated trash) to form a mixture to be heated, in Example 4-2. No chlorine removal agent was added to 4g of the *"treatable material (polyvinylidene chloride) in Comparative Example 4-1. A chlorine removal agent (slaked lime) which was not within the scope of the present invention was added in an amount of 20 g to 4 g of the treatable material to form a mixture to be heated, in Comparative Example 4-2. A chlorine removable agent (calcium carbonate) which was not within the scope of the present invention 30 was added in an amount of 20 g to 4 g of the treatable material (polyvinylidene chloride) to form a mixture to be heated, in Comparative Example 4-3. The chlorine removal agent was in the form of powder having an average particle size of 100 Am, in all Examples and Comparative Examples.

Specifically, in the experiment for each Example or Comparative Example, the predetermined amount of the treatable material was put into a tank or furnace, and then 20 g of the chlorine removal agent was added to and mixed with the treatable material in the tank to form the above-mentioned mixture, except for Comparative Example 4-1. Then, the tank was tightly sealed so that the inside the tank was isolated from the outside air or atmospheric air in order that the mixture was subjected to dry distillation upon heating. The thus sealed tank was stepwise heated with a heating coil, in which heating was made at eight temperature steps of 250 °C, 300 O, 350 0C, 400 0C, 450 C, 500 550 0C, 600 In this heating process, the temperature at each of the eight steps was kept for minutes, in which a concentration of hydrogen chloride gas in the tank was measured at each temperature rising time (at which the temperature was rising from one temperature step to the next temperature step) and at each temperature keeping time (at which the temperature at each temperature step was keeping). The temperature rising time is indicated as "Rising time" while the temperature keeping time is indicated as "Keeping time" in Table 6.

The tank was provided with a gas discharge pipe through which gas and pressure generated in the tank upon heating was discharged out of the tank. The measurement of the hydrogen chloride gas concentration was accomplished by using a detector tube according to JIS (Japanese Industrial Standard) K0804, in which the detector tube was inserted into the gas discharge pipe to measure the hydrogen chloride gas concentration. Results of the hydrogen chloride gas concentration measurement were shown in Table. 6. It 30 is to be noted that ten times of the above experiment were repeated to obtain ten actual measured values of the hydrogen gas concentration for each Example and Comparative Example, in which the measured value (shown in Table 6) for each Example indicates the highest value in the measured values while the measured value (shown in Table 6) for each Comparative Example indicates the lowest value in the measured values. Additionally, "ND" in Table 6 indicates the fact that no hydrogen chloride gas was detected in any of 10 times hydrogen chloride gas concentration measurements to obtain the ten actual measured values. Further, manners of posttreatment for the chlorine removal agent were inspected and shown as "Post-treatment for chlorine removal agent" in Table 6.

As appreciated from the above, it has been revealed that the hydrogen carbonate or carbonate containing an alkali metal, serving as the chlorine removal agent, can effectively convert noxious chlorine-containing gas into harmless chloride under a reaction in which the alkali metal reacts with chlorine to form chloride of alkali metal. A preliminary test (Comparative Example 4-1) was conducted in which polyvinylidene chloride containing a large amount of chlorine component was used as the treatable material. As a result of this test, it was confirmed that a large amount of hydrogen chloride was generated as shown in the column of Comparative Example 4-1 in Table 6.

Subsequently, comparative tests (Comparative Examples 4-2 and 4-3) were conducted in which slaked lime and calcium carbonate were respectively used as the conventional chlorine removal agents. As a result, generation of hydrogen chloride could be suppressed to some extent; however, it was confirmed that such a suppression effect due to the conventional chlorine removal agents was not sufficient and was required to be further improved.

In view of the above, as a result of a variety of investigations and considerations, attention had been paid to potassium hydrogen carbonate and potassium carbonate and 30 selected potassium hydrogen carbonate as the chlorine removal agent in the experiments, and conducted tests (Examples 4-1 and 4- As a result of the tests, it has been revealed that generation of hydrogen chloride could be generally completely suppressed at any 41 temperature regions, and that sodium hydrogen carbonate was very excellent as the chlorine removal agent. Thus, the above reveals that if potassium hydrogen carbonate and/or potassium carbonate (to be able to react with chloride) is added to the treatable material to form the mixture to be subjected to the thermal treatment, chlorinecontaining gas generated from the treatable material can effectively dechlorinated and become harmless.

Hereinafter, discussion will be made depending upon the above experimental results shown in Table 6.

First in case that polyvinylidene chloride was used as the treatable material containing a large amount of chlorine component and that no chlorine removal agent was used as shown in Comparative Example 4-1, a large amount of hydrogen chloride gas was generated throughout a wide temperature region in the thermal treatment or heating process. Generation of hydrogen chloride gas could be suppressed to some extent as compared with Comparative Example 4-1, in Comparative Examples 4-2 and 4-3 where slaked lime and calcium carbonate were added as the chlorine removal agent to the treatable material, respectively. However, it was confirmed that such suppression for hydrogen chloride gas was insufficient.

In contrast, in Example 4-1 where potassium hydrogen carbonate was added as the chlorine removal agent to the treatable material, no generation of hydrogen chloride gas could be detected throughout the whole temperature regions in the heating process, demonstrating that the potassium hydrogen carbonate was very excellent for the chloride removal agent. Additionally, in Examples 4-2 where potassium hydrogen carbonate was added as the chlorine "o.i removal agent to the treatable material (the simulated trash), 30 generation of a slight amount of hydrogen chloride was found; however, no substantial generation of hydrogen chloride gas could be detected throughout the whole temperature regions in the heating process.

It is to be noted in the above experiments, that potassium hydrogen carbonate (KHCO,) was decomposed to separate C03 at a temperature lower than a level at which hydrogen chloride (HC1) was generated from the treatable material, thereby forming an atmosphere where residual KH smoothly reacted with HC1 generated, as follows: KH C0 3 HC1 KC1 H20 C02 Accordingly, HC1 and KH smoothly react with each other to form harmless chloride (KCI).

In contrast, in case of calcium carbonate (CaCO,) or slaked lime (Ca(OH) 2 it was assumed that harmless chloride (CaCl) was formed similarly to the above; however, reaction therefor was not smooth as compared with the above case of the chlorine removal agent containing potassium.

In conclusion, it has been confirmed that addition of potassium hydrogen carbonate and/or potassium carbonate (to be able to react with chloride) to the treatable material in the thermal treatment or heating process can effectively accomplish dechlorination of chlorine-containing gas generated from the 20 treatable material thereby causing the chlorine-containing gas to become harmless. It is to be noted that experiments similar to the :...•above were conducted heating the treatable material at a higher temperature condition over 600 C which exhibited similar experimental results to the above. The temperature for heating the mixture of the treatable material and the chlorine removal agent is preferably within a range of not higher than 1000 °C from the view point of the fact that a facility for carrying out the chlorine removal process of the present invention is required to be large-sized if the temperature is raised over 1000 *C.

30 Discussion will be made on reactions carried out in the chlorine removal process of this embodiment. In case that potassium hydrogen carbonate (KHCO,) is used as the chlorine removal agent, the following reaction is made between potassium hydrogen carbonate and hydrogen chloride (HC): KHCO HC1 KC1 H20 CO 2 Thus, potassium hydrogen carbonate reacts with hydrogen chloride thereby to form harmless potassium chloride and carbon dioxide gas.

In case of using potassium carbonate (K 2 CO3) as the chlorine removal agent, the following reaction is made between potassium carbonate and hydrogen chloride:

K

2

CO

3 2HC1 2KC1 H 2 0 CO 2 Thus, potassium carbonate reacts with hydrogen chloride thereby to form harmless potassium chloride, water and carbon dioxide gas.

In the above experiments, the residue was left in the tank after the heating process had been completed. The residue was subjected to inspection, upon which it was detected that the residue did not contain noxious chlorine-containing gas component and contained harmless chloride or potassium chloride. The residue was put into water and stirred for 10 minutes, in which potassium chloride was dissolved in water while carbonized materials remained. It was also detected that the carbonized materials did not .i contain chlorine-containing gas component. Accordingly, chlorinecontaining compound and chlorine component in the treatable material can be converted into potassium chloride (KC1), water (H20) and carbon dioxide gas (CO 2 and therefore hydrogen chloride forming part of a source of dioxin cannot be formed thereby realizing the unexpected result of making both emitted gas and residue harmless. It will be appreciated that, in this embodiment, alkali metal hydrogen carbonate and/or alkali metal carbonate, such as 30 potassium hydrogen carbonate and/or potassium carbonate is used as the chlorine removal agent.

As will be understood, in the heating process in which the reactions according to the above chemical reactions are made, KC1 is 44 formed. KC1 is a harmless chloride and can be effectively removed under a rinsing or dissolving treatment with water or the like. After the rinsing treatment, solid residual materials or carbonized materials remain in the tank and reusable. Accordingly, the residual materials can be separated into respective materials which are different in characteristics by any separating means. The separated respective materials are dried and massed to be usable as fuel or the like. Additionally, liquid (such as water) used for the above rinsing treatment hardly contains no noxious substances and therefore can be discharged as it is to a river and the sea. More specifically, the residue taken out from the tank contains harmless chloride or potassium chloride (KC1). In order to extract the carbonized materials, the residue is put into a water tank containing water, and stirred for a predetermined time thereby dissolving sodium chloride.

Subsequently, solid materials in the water tank are taken out from the water tank and then are subjected to a centrifugal dehydration to separate water content from the solid materials. The thus dehydrated solid materials are dried and massed. Water remaining in the water tank and the separated water content are drained through a separate draining and treatment means. It will be appreciated that carbon contents in the massed solid materials can r...be used as fuel while inorganic contents in the hardened mass can be used as materials for glass and cement. Further, as discussed above, ~the residue can be separated into respective materials which are different in characteristics by any separating means, upon which the separated respective materials are dried and massed to be effectively used as fuel or the like.

Next, a fifth embodiment of the noxious component removal process according to the present invention will be discussed.

30 This noxious component removal process is for removing noxious component (such as chlorine and/or sulfur) from a treatable material (such as urban waste or trash, or industrial waste) containing the noxious component (such as chlorine and/or sulfur). The treatable material may contain polyvinyl chloride, polyvinylidene chloride, a synthetic resin containing chlorine, a rubber containing chlorine, so-called shredder dust (dust or trash produced by a paper-shredder), articles formed of polyvinyl chloride or polyvinylidene chloride, used tires, and formed polystyrene.

The noxious component removal process of this embodiment comprises the following steps in the sequence set forth: mixing the treatable material and a noxious component (chloride and/or sulfur) removal agent to form a mixture, the noxious removal agent containing an alkali metal compound; and heating the mixture to thermally decompose the treatable material to generate a noxious component (chlorine and/or sulfur)-containing substance and cause the noxious component-containing substance to contact and react with the noxious component removal agent to form a harmless compound.

In this embodiment, the noxious component removal agent contains at least one of alkali metal carbonate, alkali metal hydrogen carbonate, and alkali metal hydroxide, at least one of sodium hydrogen carbonate (NaHCO 3 sodium carbonate (Na 2

CO

3 20 sodium sesqui carbonate (Na 2

CO

3 NaHCO 3 2H 2 natural soda (containing Na 2

CO

3 NaHCO 3 2H 2 sodium hydroxide (NaOH), potassium hydroxide (KOH), potassium carbonate (K 2 C0 3 and potassium hydrogen carbonate (KHCO 3 potassium sodium carbonate (KNaCO, 6H 2 0).

In this embodiment, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, sodium hydroxide or potassium hydroxide is used to be mixed with the treatable material which contains a large amount of chlorine and sulfur.

According to this embodiment, prior to a heating treatment is 30 applied to the treatable material including chlorine-containing substance and sulfur-containing substance (substance containing sulfur) which will respectively generate chlorine-containing gas and sulfur-containing gas (gas containing sulfur) upon heating, the chloride removal agent is added to and mixed with the treatable material thereby to form the mixture. By heating this mixture in the low oxygen concentration atmosphere, the chlorine-containing substance is thermally decomposed at a predetermined temperature thereby generating harmful chlorine-containing gas and sulfurcontaining gas. This chlorine-containing gas and sulfur-containing gas immediately react with the noxious component removal agent thus to form harmless chloride (NaC1, KC) and sulfite (Na 2

SO,,

K

2 S0 3 This embodiment will be discussed with reference to Fig. 1 illustrating a chlorine and sulfur removal system by which the process of this embodiment is carried out.

The chlorine and sulfur removal system comprises a mixing means or device 1 for mixing the treatable material (such as pulverized waste or trash) and the noxious component removal agent (such as sodium hydrogen carbonate) to form a mixture. A thermal treatment furnace 2 is formed cylindrical and rotatable. The mixture formed by the mixing device 1 is supplied into the furnace 2. The mixture may be formed by other means or devices than the mixing 20 device 1. The thermal treatment furnace 2 is provided with a Srotating transferring means or device (not shown) which is adapted to transfer the mixture under stirring. In the furnace 2, the mixture of the treatable material and the noxious component removal agent is heated in the low oxygen concentration atmosphere to accomplish thermal decomposition of the treatable material. The furnace 2 is provided with a heating coil 2 for heating the content of the furnace 2.

A residue treatment means or device 4 is provided to treat the residue (ash) formed upon heating the treatable material in the 30 furnace 2. The residue is taken out of the furnace 2 and subjected to a solid-liquid separation. In this solid-liquid separation, the residue is rinsed with liquid such as water so that formed chloride and/or .i :sulfite are separated and removed and then taken out from a liquid 47 discharge section 4a. The residual solid such as metals and carbonized materials are taken out from a solid take-out section 4b.

Emitted gas from the thermal treatment furnace 2 is introduced into an emitted gas treatment means or device 5. It will be understood that the emitted gas has been made harmless because the noxious components in the treatable material is removed under the action of the noxious component removal agent. A necessary treatment is made to the introduced emitted gas in the emitted gas treatment device 5. The treated gas from the gas treatment device 5 is then introduced into a gas recovery means or device 6 for recover the gas or into a secondary combustion means or device 7 to make secondary combustion of the gas to be discharged.

In this noxious component removal process using the above noxious component removal system, the treatable material containing the noxious component(s) and the noxious component removal agent (such as sodium hydrogen carbonate) are cast into the mixing device 1 and sufficiently mixed with each other, and then cast into the thermal treatment furnace 2. The treatable material may be pulverized prior to being cast, or pulverized simultaneously 20 with mixing between the treatable material and the noxious component removal agent. The amount of the noxious component removal agent is within a range of from 5 to 30 by weight relative to the treatable material. The thermal treatment or heating of the mixture in the thermal treatment furnace 2 is accomplished within temperature and time ranges to cover the temperature and time of *generation of HC1 gas and SOx gas from the treatable material, the temperature (for example, 600 and time (for example, 1 hour) having been determined under a previous investigation. These 9 "temperature and time are in relation to a condition (such as the size 30 and the heating coil) of the thermal treatment furnace, the treatment amount of the treatable material, the treatment time of S:i" the thermal treatment of the treatable material, the treatment temperature of the thermal treatment of the treatable material.

48 Therefore, the above temperature and time are required to be previously determined under a sufficient investigation and to accumulate the data to be taken for the temperature and time.

The thermal treatment in this process is under a heating condition for accomplishing dry distillation (or thermal decomposition) of the treatable material and therefore is not under another heating condition for accomplishing combustion or incineration of the treatable material. Under this thermal treatment, noxious HC1 gas and SOx gas can be effectively react with each other upon contact of them, so that noxious HC1 gas and SOx gas are converted respectively into harmless chloride and sulfite.

In order to maintain this heating condition, a total reaction atmosphere or circumference inside the thermal treatment furnace can meet necessary conditions and be stable. For example, the stable low oxygen concentration atmosphere is formed inside the thermal treatment furnace. In other words, it is necessary to supply fresh air only around the treatable material during the heating or thermal treatment. If fresh air is supplied to around the treatable material, there is the possibility of combustion of the treatable 20 material being initiated to make reaction stable. Otherwise, it has been experimentally confirmed that the heating condition can be °...maintained even by supplying fresh air into the thermal treatment furnace in such a manner that fresh air reaches whole the pulverized treatable material under a condition where unburned state of the treatable material is kept.

r During the thermal treatment in the furnace, decomposition gas containing HC1 gas and SOx gas are generated, in which HC1 and SOx components immediately react with the noxious o component removal agent or sodium hydrogen carbonate thereby to 30 form harmless chloride (such as NaC1) and sulfite (Na 2 SO), so that noxious HC1 and SOx are removed from the decomposition gas. The residue formed upon the thermal treatment of the treatable material contains no noxious HC and SOx. Thus, the decomposition gas and the residue can be simultaneously made harmless.

The residue is taken out through the residue treatment device 4 and rinsed with water or a solution thereby to separate the chloride and the sulfite from the residue, leaving solid residual material. The solid residual material contains useful metals which are effectively reusable.

Hereinafter, experiments for carrying out the noxious component removal process according to this embodiment will be discussed, in which comparison in experimental result is made between Examples (according to this embodiment) and Comparative Examples (not within the scope of the present invention). The experiments have revealed that the noxious component removal agent of this embodiment effectively react with HC1 gas and SOx gas so as to make harmless emitted gas and residue.

In the experiments, the noxious component removal process of this embodiment was carried out by using a refused derived fuel (referred hereinafter to as "RDF") as the treatable material. The RDF was formed from a waster or refuse and contains the following components: garbage including refuse of meat, fish, bone, egg-shell, vegetable, fruit and the like; *°plastic waste including polyethylene, polypropylene, polystyrene, polyvinylidene chloride, and the like; papers including tissue paper, advertisement bill, paper bag, paper box, and paper packing for drink, and the like; and *o combustibles including fiber matters such as fabric, wood piece, rubber, leather and the like.

.I :As a result of analysis, it had been confirmed that RDF Osseo* 30 used in the experiments contained 60.173 by weight of carbon 16.277 by weight of oxygen 10.745 by weight of silicon (Si), 7.045 by weight of calcium 3.314 by weight of aluminum 0.888 by weight of magnesium 0.505 by weight of phosphorus 0.466 by weight of chlorine 0.331 by weight of sulfur and 0.155 by weight of potassium 0.101 by weight of sodium (Na).

The experiments in connection with the present invention (Examples) used RDF (not subjected to thermal treatment or incineration) as the treatable material, whereas the experiments for the comparison purpose (Comparative Examples) used treated RDF (subjected to the thermal or incineration). For reference, in general, RDF whose main component is plastic contains 0.29 to 0.89 by weight of chlorine component, and RDF whose main component is paper contains 0.2 by weight of chlorine component. Additionally, it is general that the treated RDF contains about 1.0 by weight of sulfur component.

As shown in Table 7, concerning Examples, 10 g of the chlorine removal agent (sodium hydrogen carbonate) was added to g of the treatable material (crushed RDF) to form a mixture to be heated, in Example 5-1. The chlorine removal agent (sodium hydrogen carbonate) in an amount of 4g was added to 40 g of the treatable material (crushed RDF) to form a mixture to be heated, in S 20 Example 5-2. The chlorine removal agent (potassium hydrogen carbonate) in an amount of 3 g was added to 40 g of the treatable 00 material (crushed RDF) to form a mixture to be heated, in Example 5-3. The chlorine removal agent (sodium carbonate and potassium 0000 carbonate) in an amount of 3 g was added to 20 g of the treatable material (crushed RDF) to form a mixture to be heated, in Example 5-4. The chlorine removal agent (sodium hydroxide) in an amount of 3 g was added to 20 g of the treatable material (crushed RDF) to form a mixture to be heated, in Example 5-5. The chlorine removal agent (potassium hydroxide) in an amount of 3 g was added to 20 g of the see** 30 treatable material (crushed RDF) to form a mixture to be heated, in Example 5-6. The chlorine removal agent (sodium hydrogen :-•carbonate) in an amount of 10 g was added to 40 g of the treatable material (RDF which had not been crushed and in the form of mass) material (RDF which had not been crushed and in the form of mass) 51 to form a mixture to be heated, in Example 5-7. The chlorine removal agent was in the form of powder having an average particle size of 100 m, in all Examples Concerning Comparative Examples in which no noxious component removal agent was used, 40 g of the treated RDF which had been crushed was used as the treatable material in Comparative Example 5-1. The treated RDF which had been crushed was used in an amount of 20 g as the treatable material in Comparative Example 5-2. The treated RDF which had been not crushed and in the form of mass was used in an amount of 20 g as the treatable material in Comparative Example 5-3.

The experiment for each Example was conducted as follows: A predetermined amount of the treatable material was put into a tank or furnace, and then 20 g of the noxious component removal agent was added to and mixed with the treatable material in the tank to form the above-mentioned mixture. In the experiment for each Comparative Example, a predetermined amount of the treatable material was put into a tank or furnace. Then, the tank was tightly sealed so that the inside the tank was isolated from the 20 outside air or atmospheric air in order that the mixture or only the S" treatable material was subjected to dry distillation upon heating.

The thus sealed tank was stepwise heated with a heating coil, in which heating was made at eight temperature steps of 250 0C, 300 0C, 350 0C, 400 0C, 450 0C, 500 550 0C, 600 0C. In this heating step, the temperature at each of the eight steps was kept for 5 minutes, in which a concentration of HC1 gas and a concentration of S02 in the tank was measured at each temperature rising time (at which the temperature was rising from one temperature step to the next **temperature step) and at each temperature keeping time (at which the temperature at each temperature step was keeping). The temperature rising time is indicated as "Rising time" while the temperature keeping time is indicated as "Keeping time" in Tables 7 and 8. The tank was provided with a gas discharge pipe through which gas and pressure generated in the tank upon heating was discharged out of the tank. The measurement of the hydrogen chloride gas concentration was accomplished by using a detector tube according to JIS (Japanese Industrial Standard) K0804, in which the detector tube was inserted into the gas discharge pipe to measure HC1 and SO, gas concentrations. Results of HC1 and SO 2 gas concentration measurement were shown in Tables 7 and 8. It is to be noted that ten times of the above experiment were repeated to obtain ten actual measured values of the hydrogen gas concentration for each Example and Comparative Example, in which the measured value (shown in Table 7) for each Example indicates the highest value in the measured values while the measured value (shown in Table 8) for each Comparative Example indicates the lowest value in the measured values. Additionally, "ND" in Tables 7 and 8 indicates the fact that no hydrogen chloride gas was detected in any of times HC1 and S0 2 gas concentration measurements to obtain the ten actual measured values. Further, manners of post-treatment for the noxious component removal agent were inspected and shown as "Post-treatment for chlorine removal agent" in Tables 7 and 8.

The experimental results will be discussed hereinafter with reference to Tables 7 and 8.

Regarding hydrogen chloride gas (HC1): In case that the treatable material was crushed, a slight amount of HC1 gas was detected in Example 5-4; however, no HC1 gas was detected in other Examples so that the noxious :ocomponent removal agents were highly effective for suppressing generation of HC1 gas. This HC1 gas generation suppression effect o. was considerably high as compared with Comparative Examples 1 and 5-2.

In case that the treatable material was not crushed and used in the form of mass, a slight amount of HC1 gas was detected at the temperature steps of 350 to 450 'C in Example 5-7 as compared with the case that the treatable material was crushed; however, it was confirmed that the results in Example 5-7 was considerably good as compared with those in Comparative Examples.

Regarding sulfur oxide gas In case that the treatable material was crushed, a slight amount of SO2 gas was detected at the temperature steps of 400 to 450 'C in Examples 5-1 to 5-6; however, the results of Examples were very good as a whole so that the noxious component removal agents were highly effective for suppressing generation of SO2 gas. This S02 gas generation suppression effect was considerably high as compared with Comparative Examples 5-1 and 5-2.

In case that the treatable material was not crushed and used in the form of mass, a slight amount of S02 gas was detected at the temperature steps of 350 to 450 'C in Example 5-7 as compared with the case that the treatable material was crushed; however, it was confirmed that the results in Example 5-7 was considerably good as compared with those in Comparative Example 5-3.

As a result of the above experimental results and investigations, it has been confirmed that HC1 and SOx can be 20 generally completely made harmless by using the noxious :o component removal agent containing the alkali metal compound which effectively reacts with HCl and SOx to form harmless chloride and sulfite. Thus, the above reveals that if the noxious component removal agent is added to the treatable material to form the mixture 25 to be subjected to the thermal treatment, chlorine-containing gas o:o and sulfur-containing gas generated from the treatable material can effectively become harmless.

It is to be noted that experiments similar to the above were conducted heating the treatable material at a higher temperature condition over 600 which exhibited similar experimental results to the above. The temperature for heating the mixture of the treatable material and the chlorine removal agent may be selected according to form of facilities for accomplish the thermal treatment, time of the thermal treatment, amount of the treatable material and the like.

Subsequently, discussion will be made on mechanisms of reaction between the noxious component removal agent and noxious gas (chlorine-containing gas and sulfur-containing gas), realizing unexpected results in which both emitted gas and residue are made harmless.

Regarding hydrogen chloride gas (HC1): It was confirmed that sodium hydrogen carbonate (NaHCO 3 sodium carbonate (Na 2 CO), sodium sesqui carbonate (Na 2 CO NaHCO, 2H 2 natural soda (containing Na 2 CO, NaHC 3 2H 2 sodium hydroxide (NaOH), potassium hydroxide (KOH), potassium carbonate (K 2

CO

3 and potassium hydrogen carbonate (KHCO,) can react with noxious HC1 thereby to convert HC1 into harmless chloride (NaC1 and KC1) according to reaction formulae discussed before. It will be understood that sodium potassium carbonate and sodium carbonate hydrate can also react with noxious HC1 similarly to the above.

Particularly in case of using the alkali metal hydrogen carbonate as the noxious component removal agent, the following t. 0. tendency is predominant: First, CO 2 is separated at a temperature below a level (not lower than 250 at which hydrogen chloride o. (HC1) is generated upon decomposition of the treatable material, forming NaOH or KOH. It is supposed that this forms an atmosphere 25 in which reaction between NaOH or KOH and HC1 is made smoothly.

Here, the following reactions are made: In case of sodium hydrogen carbonate, NaHCO, NaOH CO 2 NaOH HC1 NaC1 H,O In case of potassium hydrogen carbonate,

KHCO

3 KOH CO 2 KOH HC1 KC1 HO Thus, NaOH or KOH smoothly reacts with HC1 thereby to newly form harmless chloride (NaCI, KC1).

After the thermal treatment, the residue was left in the tank after the heating process had been completed. The residue was subjected to inspection, upon which it was detected that the residue did not contain noxious chlorine-containing gas component and contained harmless chloride (sodium chloride or potassium chloride).

The residue was put into water and stirred for 10 minutes, in which the chloride was dissolved in water while carbonized materials remained. It was also detected that the carbonized materials did not contain chlorine-containing gas component.

Accordingly, chlorine-containing compound and chlorine component in the treatable material can be converted into sodium chloride (NaC1), potassium chloride (KC1), water (H 2 0) and carbon dioxide gas and therefore hydrogen chloride forming part of a source of dioxin cannot be formed thereby realizing the unexpected result of making both emitted gas and residue harmless.

Regarding sulfur oxide gas (SOx): It was confirmed that the noxious component removal 20 agent reacts with noxious SOx thereby to convert SOx into harmless sulfite as follows: In case that sodium hydrogen carbonate is used as the noxious component removal agent, NaHCO 3 NaOH CO 2 25 2NaOH SO, Na 2 SO, H 2 0 In case that potassium hydrogen carbonate is used as the noxious component removal agent, KHCO, KOH CO, 2KOH SO, KSO3 HsO In case that sodium hydroxide is used as the noxious component removal agent, 2NaOH SO, NaSO, H 2

O

M_

In case that potassium hydroxide is used as the noxious component removal agent, 2KOH S02 K 2 S0 3

H

2 0 In case that sodium potassium carbonate is used as the noxious component removal agent, (Na 2 HCO, K 2 CO,) 2SO Na 2

SO

3

K

2 SO, 2CO2 Particularly in case of using the alkali metal hydrogen carbonate as the noxious component removal agent, the following tendency is predominant: First, CO, is separated at a temperature below a level (not lower than 300 at which sulfur oxide (SO 2 is generated upon decomposition of the treatable material, forming NaOH or KOH. It is supposed that this forms an atmosphere in which reaction between NaOH or KOH and SO2 is made smoothly.

Here, the following reactions are made: In case of sodium hydrogen carbonate, NaHCO, NaOH CO, 2NaOH SO, NaSO 3

H

2 0 In case of potassium hydrogen carbonate,

KHCO

3 KOH CO2 2KOH SO, K2SO3 HO2 Thus, NaOH or KOH smoothly reacts with S02 thereby to newly form harmless sulfite (Na 2

SO

3

K

2

SO,).

It was confirmed sodium carbonate (Na 2 CO), sodium sesqui carbonate (Na 2

CO

3 NaHCO, 2H 2 natural soda 25 (containing Na 2 CO NaHCO, 2H,0), potassium carbonate (KXCO), and sodium carbonate hydrate can react with noxious SO, thereby to convert SO into harmless chloride sulfite (Na 2 SO K2SO3) according to reaction formulae discussed hereinbefore.

Upon the above-mentioned inspection of the residue, it was detected that the residue did not contain noxious sulfurcontaining gas (SOx gas) component and contained harmless sulfite .i (Na 2

SO

3

K

2 SO3). The residue was put into water and stirred for minutes, in which the alkali metal sulfite was dissolved in water while carbonized materials remained. It was also detected that the carbonized materials did not contain sulfur-containing (SOx) gas component.

Accordingly, sulfur-containing compound and sulfur component in the treatable material can be converted into sodium sulfite (Na 2 SO,) in powder form, and potassium sulfite (K2SO,) in powder form, water (H 2 0) and carbon dioxide gas (CO 2 and therefore SOx gas can be prevented from generation thus realizing the unexpected result of making both emitted gas and residue harmless.

It will be appreciated that, in this embodiment, the noxious component removal agent contains at least one of alkali metal carbonate, alkali metal hydrogen carbonate, and alkali metal hydroxide, at least one of sodium hydrogen carbonate (NaHCO 3 sodium carbonate (Na 2

CO

3 sodium sesqui carbonate (Na 2

CO,

NaHCO, 2H 2 natural soda (containing Na 2

CO

3 NaHCO, 2H 2 sodium hydroxide (NaOH), potassium hydroxide (KOH), potassium carbonate (K 2 and potassium hydrogen carbonate (KHCO,), potassium sodium carbonate (KNaCO, 6H 2 As will be understood, in the heating process in which the reactions according to the above chemical reactions are made, noxious hydrogen chloride and/or sulfur oxide are converted into harmless chloride (NaC1, KC1) and/or sulfite (Na 2

SO

3

K

2 S0 3 thereby making it possible to remove noxious components (hydrogen chloride and/or sulfur oxide) from the 25 decomposition gas generated from the treatable material upon heating. Thus, the decomposition gas or emitted gas from the furnace can be effectively made harmless. The chloride and/or sulfite form part of the residue and can be effectively removed under a rinsing or dissolving treatment with water or the like. After the rinsing treatment, solid residual materials or carbonized materials remain in the tank and reusable. Accordingly, the residual materials can be separated into respective materials which are different in characteristics by any separating means. The separated respective 58 materials are dried and massed to be usable as fuel or the like.

Additionally, liquid (such as water) used for the above rinsing treatment hardly contains no noxious substances and therefore can be discharged as it is to a river and the sea.

4• .4 .9 p a 9*h ~4s 9 4 as 34~ *4.

9 9*.

4 a. S. 9* *94 a S.

I

C 5 S S 954 94 TABLE 1 Item Sample Example 1-1 Comparative Comparative Comparative 1-1 Example 1-2 Example 1-3 Treatable material Polyvinylidene chloride 4g 4g 4g 4g Chlrie rmoal Sodium hydrogen carbonate agent Slaked lime 20g I Calcium carbonate F TABLE 2 Item Sample Example Example Example Example 1-2 1-3 1-4 Traal aeil Simulated trash 20g 20g 20g Polyvinylidene chloride ig 0.5g 0.l1g Chlorine removal agent Sodium hydrogen carbonate 5g 2.5g 0.5g Water content City water 40 0 00 0 000 V S *01 U 009 0 0 *0 0 00 0 008 00.

0 0 *0 0 *0 I 0* *04 00 004 0 0 006..

09 00 000 0 0 00 000 00 0 *t 0 00 000 00 TABLE 3 Item Treatable material Item Example -1-1 Polyvinylidene chloride (4g) Example 1-2 Polyvinylidene chloride (1g) Simulated trash (20g) Example 1-3 Polyvinylidene chloride (0.5g) Simulated trash (20g) Example 1-4 Polyvinylidene chloride (0.l1g) Simulated trash (20g) Sodium hydrogen carbonate (0.5g) ChlorineT removal agent Sodium hydrogen carbonate (20g) Sodium hydrogen carbonate Sodium hydrogen carbonate (2.5g) Example 1-5 Simulated trash Water Sodium hydrogen carbonate (5g)

HCI

concentration (not higher than)

ND

Comparative Example 1-1 Polyvinylidene chloride (4g)

HCI

concentration (not lower than)-

ND

450ppm lOO0ppm Comparative Example 1-2 Polyvinylidene chloride (4g) Slaked lime (20g)

HCI

concentration (not lower than)

ND

lppm Comparative Example 1-3 IPolyvinylidene (4g) Calcium carbonate

HCI

concentration (not lower than)

ND

(5g) .9 1 Temp. Measuring time

HCI

concentration (not higher than)

I

HCI

concentration (not higher than)

HCI

concentration (not higher than)

HCI

concentration (not higher than)

ND

IRising time IND I

J.

K~eeping time IND 4- 1 300 Rising time Keeping timel

ND

1 ising time IND 1ND 4ppm I I r 1 wuppii ippm 350ppm Keeping thrnp NT) I, Mn 400 Rising time ND ND ND ND ND lOO0ppm 8ppm ___Keeping time ND ND ND ND ND lOO0ppm ND 40Rising time ND ND ND ND lppm 650ppm Sppm loppm timne ND ND ND ND 3ppm 400ppm ND 7ppm time ND ND ND ND 20ppm lOO0ppm ND 3ppm 500Keeping time ND ND ND ND ND 58Oppm ND ND time ND ND ND ND ND lOO0ppm ND ND time ND ND ND ND ND SO0ppm ND ND 00Rising time ND ND ND ND ND 600ppm ND ND time ND ND ND ND ND 50ppm ND ND P ost-treatm en t for e o u l n w t r S l b ei a e l g t yS i h l chlorine removal Soluble in water Soluble in water Soluble in wate Soluble in water oluble in watergtylihy agent soul in waeIouleiae a_ *g 9O a 6 6* S S *5 Ar.

TA B L4 TABLE 4 Item Example Example Comparative Comparative Comparative Comparative 2 1 2-2 Example 2-1 Example 2-2 Example 2-3 Example 2-4 Treatable Polinylidene Polyvinylidene Polyvinylidene Polyvinylidene Polyvinylidene Polyvinylidene material chloride chloride chloride chloride chloride chloride ma l (4g) (4g) (1g) (4g) (4g) (4g) Item Chlorine Sodium Potassium Calcium removal hydroxide hydroxide Slaked lime ci agent (20g) (20g) (20g) carbonate Temp. HC HCI HC HCI HCl HCI Temp. Measuring concentration concentration concentration concentration concentration concentration 0 C time (not higher than) (not higher than) (not lower than) (not lower than) (not lower than) (not lower than) 250 Rising time ND ND ND ND ND ND Keeping time ND ND ND ND ND ND 300 Rising time ND ND ND 450ppm lppm Keeping time ND ND ND 1000ppm 4ppm 350 Rising time 3ppm ND ND 1000ppm 280ppm 350ppm Keeping time ND ND 60ppm 1000ppm 15ppm 400 Rising time ND ND 480ppm 1000ppm 8ppm Keeping time ND ND 1000ppm 1000ppm ND 450 Rising time lppm ND 1000ppm 650ppm 5ppm Keeping time ND 2ppm 1000ppm 400ppm ND 7ppm 500 Rising time ND ND 500ppm 1000ppm ND 3ppm Keeping time ND ND 400ppm 580ppm ND ND 550 Rising time ND ND 200ppm 1000ppm ND ND Keeping time ND ND 240ppm 500ppm ND ND 600 Rising time ND ND 60ppm 600ppm ND ND 6 Keeping time ND ND 30ppm 50ppm ND ND 600- Rising time ND ND ND ND ND ND 1000 Keeping time ND ND ND ND ND ND Post-treatment for chlorine removal Soluble in water Soluble in water Slightly Slightly agent soluble in water soluble in water 9 f a 90 9 *9 4* *0 So I *0L 09, 00 00j *0S 00 0 4 4 04; 99 99 Log TABLE Item Example Example 3-1 3-2 Treatable material Chlorine removal agent Polyvinyl chloride (4g) Sodium hydrogen carbonate (20g) Polyvinylidene chloride (4g) Comparative Example 3-1 Polyvinylidene chloride (lg) Comparative Comparative Example 3-2 Example 3-3 Polyvinylidene Polyvinylidene chloride chloride (4g) (4g) (ig) I Sodium hydrogen carbonate (20g) (4g (4g Calcium carbonate (20g) Slaked lime HCI HCI HCI HCI

HCI

Te o p M easng concentration concentration concentration concentration concentration C i time (not higher than) (not higher than) (not lower than) (not lower than) (not lower than) 250 Rising time ND ND ND ND ND Keeping time ND ND ND ND ND 300 Rising time ND ND 450ppm 15ppm 1ppm Keeping time ND ND 1000ppm 35ppm 4ppm 350 Rising time ND ND 1000ppm 350ppm 280ppm Keeping time ND ND 1000ppm 50ppm 400 Rising time ND ND 1000ppm 20ppm 8ppm Keeping time ND ND 1000ppm 15ppm ND 450 Rising time ND ND 650ppm 10ppm Keeping time ND ND 400ppm 7ppm ND 500 Rising time ND ND 1000ppm 3ppm ND Keeping time ND ND 580ppm ND ND 550 Rising time ND ND 1000ppm ND ND Keeping time ND ND 500ppm ND ND 600 Rising time ND ND 600ppm ND ND Keeping time ND ND 50ppm ND ND Post-treatment for chlorine removal Soluble in water Soluble in water Slightly Slightly agent soluble in water soluble in water A a 4 N N I I 1 0 N I a.

a a a a..

9

S

*5 9 a.

a.

a *a *9 a a a.4 a* a a S. 5 a TABLE 6 Item Example Example Comparative Comparative Comparative 4-1 4-2 Example 4-1 Example 4-2 Example 4-3 Polyvinylidene Polyvinylidene Polyvinylidene Polyvinylidene chloride chloride chloride chloride Treatable (4g) (4g) (4g) (4g) material Item Simulated trash Potassium Potassium Chlorine hydrogen hydrogen Slaked lime Calcium removal carbonate carbonate (20g) carbonate agent (10g) (10g) HCI HCI HCI HCI HCl Temp. Measuring concentration concentration concentration concentration concentration 0 C time (not higher than) (not higher than) (not lower than) (not lower than) (not lower than) 2 Rising time ND ND ND ND ND Keeping time ND ND ND ND ND 300 Rising time ND ND 450ppm lppm Keeping time ND ND 1000ppm 4ppm 350 Rising time ND 2ppm 1000ppm 280ppm 350ppm Keeping time ND 7ppm 1000ppm 15ppm 400 Rising time ND 5ppm 1000ppm 8ppm Keeping time ND 2ppm 1000ppm ND 450 Rising time ND ND 650ppm 5ppm 0 Keeping time ND ND 400ppm ND 7ppm Rising time ND ND 1000ppm ND 3ppm Keeping time ND ND 580ppm ND ND Rising time ND ND 1000ppm ND ND Keeping time ND ND 500ppm ND ND 6 Rising time ND ND 600ppm ND ND Keeping time ND ND 50ppm ND ND Post-treatment for chlorine removal Soluble in water Soluble in water Slightly Slightly agent soluble in water soluble in water N 41 St TABLE 7 1 1 1 T example 5-1 ixample Example 5-2 5-3 Example 5-4 Example dple Example tple Example C 7 Treatable RDF RDF RDF RDF RDF RDF RDF material Crushed Crushed Crushed Crushed Crushed Crushed Mass 40g 40g 20g 20g 20g 20g NT."r',t fl Ttlt 1 INOXIOUS comp.

removable material NaHLVg 10 InaiLU3 4g KHCU3 3g Na2C03 K2C03 3v.

NaOH KOH NaHC03 HC1 S02 HC1 S02 HCI Sa02 HC1 S02 HC1 S02 HCI S02 HCI S02 concent- concent- concent- concent- concent- conent- concent- concent- concent- concent- concent- concent- conent- concent- Temp. Measuring rat ration ration ration ration ration ration ration ration ration ration ration ration ration oC time (not (not (not (not (not (not (not (not (not (not (not (not (not (not higher higher higher higher higher higher higher igher higher higher higher higher higher higher than) than) than an) than) than) than) than) than) than) than) than) than) than) 250 Rising time ND ND ND ND ND ND ND ND ND ND ND ND ND ND Keeping time ND ND ND ND ND ND ND ND ND ND ND ND ND ND 300 Rising time ND ND ND ND ND ND ND ND ND ND ND ND ND ND Keeping time ND ND ND ND ND ND ND ND ND ND ND ND ND ND Rising time ND ND ND ND ND ND ND ND ND ND ND ND ND ND Keepingtime ND ND ND ND ND ND ND ND ND ND ND ND 2ppm 400 Rising time ND ND ND 3ppm ND 5ppm 2ppm 5ppm ND 1ppm ND lppm 16ppm Keeping time ND ND ND ND ND 4ppm ND 3ppm ND ND ND ND 8ppm 450 Rising time ND ND ND ND ND lppm ND ND ND ND ND ND 2ppm 2ppm Keeping time ND ND ND ND ND ND ND ND ND ND ND ND ND ND Rising time ND ND ND ND ND ND ND ND ND ND ND ND ND ND Keeping time ND ND ND ND ND ND ND ND ND ND ND ND ND ND Rising time ND ND ND ND ND ND ND ND ND ND ND ND ND ND SKeeping time ND ND ND ND ND ND ND ND ND ND ND ND ND ND 600 Rising time ND ND ND ND ND ND ND ND ND ND ND ND ND ND SKeeping time ND ND ND ND ND ND ND ND ND ND ND ND ND ND Post-treatment for noxious comp. Soluble in water Soluble in water Soluble in water Soluble in water Soluble in water Soluble in water Soluble in water removal agent TABLE 8 Comparative Example 5-1 Comparative Example 5-2 Comparative Example 5-3 4* 4~ 44 *4 44 4 4 *4 44 .4.4 44 4 44 4 44 44 Treatable Treated RDF Treated RDF Treated RDF reateial Crushed Crushed Mass material 40g 20g Noxious comp.

removal agent HC1 S02 HC1 SO2 HCI S02 concent- concent- concent- concent- concent- concent- Temp. Measuring ration ration ration ration ration ration 0 C time (not (not (not (not (not (not lower lower lower lower lower lower than) than) than) than) than) than) Rising time ND ND ND ND ND ND 250 eping time ND ND ND ND ND ND Keeping time ND ND ND ND ND ND Keeping time ND ND ND ND ND ND 300 Keeping time ND ND ND ND ND ND Rising time ND 7ppm ND 20ppm 2ppm 6ppm 350 Keeping time 16ppm 40ppm 13ppm 17ppm 35ppm Rising time 70ppm 35ppm 30ppm 13ppm 1000ppm 400 Keeping time 60ppm 30ppm 3ppm 7ppm 130ppm Rising time 10ppm 7ppm lppm 4ppm l0ppm l0ppm 450 Keeping time 2ppm 3ppm ND ND ND Rising time ND ND ND ND ND ND 500 Keeping time ND ND ND ND ND ND Keeping time ND ND ND ND ND ND S Rsing time ND ND ND ND ND ND 550 ing time ND ND ND ND ND ND Keeping time ND ND ND ND ND ND Risingtime ND ND ND ND ND ND 600 Keeping time ND ND ND ND ND ND Post-treatment for noxious comp.

removal agent

Claims

1. A process for removing at least one of chlorine and sulfur from a treatable material containing at least one of chlorine and sulfur, comprising the following steps in the sequence set forth: mixing the treatable material and a chlorine and sulfur removal agent to form a mixture, said chlorine and sulfur removal agent containing at least one compound selected from the group consisting of a sodium compound and a potassium compound, said sodium compound being other than sodium carbonate; and heating said mixture in a low oxygen concentration atmosphere to thermally decompose the treatable material to generate at least one of a chlorine-containing substance and a sulfur-containing substance and cause at least one of the chlorine-containing substance and the a. sulfur-containing substance to contact and react with said chlorine and sulfur removal agent to form at least one of 20 harmless chloride and sulfite. rr

2. A process as claimed in claim i, wherein said chlorine and sulfur removal agent contains at least one compound selected from the group consisting of carbonate, hydrogen carbonate, and hydroxide of at least one element rr S"selected from the group consisting of sodium and potassium, said carbonate being other than sodium carbonate. -67-

3. A process as claimed in claim i, wherein said chlorine and sulfur removal agent contains at least one. compound selected from the group consisting of sodium hydrogen carbonate, sodium sesqui carbonate, natural soda, sodium hydroxide, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, and potassium sodium carbonate.

4. A process as claimed in claim i, wherein the heating step includes the step of heating said mixture in a furnace which is substantially sealed so as to prevent fresh air from being supplied into said furnace, in which a pressure in said furnace leaking out of said furnace. A process as claimed in claim i, wherein the heating step includes the step of heating said mixture to cause said treatable material to make its dry distillation.

I+ao

6. A process as claimed in claim 1, wherein said a. chlorine and sulfur removal agent is in form of at least one selected from the group consisting of mass, plate, porous body, particle, solution and suspension. a a.

7. A process as claimed in claim i, the treatable material is at least one selected from the group consisting of polyvinyl chloride, polyvinylidene chloride, -68- a synthetic resin containing chlorine, and a rubber containing chlorine.

8. A process as claimed in claim i, wherein said chlorine and sulfur removal agent in said mixing step is in an amount ranging from 0.05 to0 by weight relative to the treatable material at a time before said mixing step.

9. A process as claimed in claim i, wherein said chlorine and sulfur removal agent in said mixing step is in an amount ranging from 10 to 70 by weight relative to the treatable material in case that the treatable material is at least one selected from the group consisting of polyvinyl chloride, polyvinylidene chloride, a synthetic resin containing chlorine, and a rubber containing chlorine. 0* 44 S0 4[

10. A process as claimed in claim 1, wherein said 20 chlorine and sulfur removal agent in said mixing step is in an amount of not less than a chemical equivalent of 4044 i chlorine to be generated from the treatable material.

11. A process as claimed in claim i, further comprising the step of adding said chlorine and sulfur removal agent 54 es S to said mixture in said heating step.

12. A process as claimed in claim 11, wherein the adding step includes adding said chlorine and sulfur -69- removal agent to said mixture before a temperature of the treatable material reaches a level at which a thermal decomposition of the treatable material occurs.

13. A process as claimed in claim 11, wherein the adding step includes adding said chlorine and sulfur removal agent to said mixture after a temperature of the treatable material reaches a level at which a thermal decomposition of the treatable material occurs. I0

14. A process as claimed in claim 1, further comprising supplying said chlorine and sulfur removal agent to the treatable material in a furnace by at least one measure selected from the group consisting of casting and spraying.

15. A process as claimed in claim i, wherein said o• heating step includes heating the treatable material at a S temperature ranging from 200 to 1000 0 C.

16. A chlorine and sulfur removal agent to be used in a *SSC •process for removing at least one of chlorine and sulfur from a treatable material containing at least one of chlorine and sulfur, said chlorine and sulfur removal agent containing at least one compound selected from the group consisting of a sodium compound and a potassium compound, said sodium compound being other than sodium carbonate, said chlorine and sulfur removal agent being _contactable and able to react with at least one of a chlorine- containing substance and a sulfur-containing substance generated from the treatable material upon heating said treatable material, so as to form at least one of harmless chloride and sulfite.

17. A chlorine and sulfur removal agent as claimed in claim 16, wherein said alkali metal compound is at least one compound selected from the group consisting of carbonate, hydrogen carbonate, and hydroxide of at least one element selected from the group consisting of sodium and potassium, said carbonate being other than sodium carbonate.

18. A chlorine and sulfur removal agent as claimed in claim 16, wherein said alkali metal compound is at least one compound selected from the group consisting of at least one compound selected from the group consisting of sodium hydrogen carbonate, sodium sesqui carbonate, natural soda, sodium hydroxide, potassium hydroxide, ~r 20 potassium carbonate, potassium hydrogen carbonate, and potassium sodium carbonate.

19. An apparatus for removing at least one of chlorine sulfur from a treatable material containing at least one of chlorine and sulfur, said apparatus comprising: S.a device for mixing the treatable material and a chlorine and sulfur removal agent to form a mixture, said chlorine and sulfur removal agent containing at least one Scompound selected from the group consisting of a sodium -71- compound and a potassium compound, said sodium compound being other than sodium carbonate; a furnace into which said mixture of the treatable material and said chlorine and sulfur removal agent is supplied, said furnace being adapted to form therein a low oxygen concentration atmosphere; and a heating device for heating said mixture in the low oxygen concentration atmosphere in said furnace to thermally decompose the treatable material so as to accomplish dry distillation of said treatable material, in which said mixture generates at least one of a chlorine- containing substance and a sulfur-containing substance and cause at least one of the chlorine-containing substance and the sulfur-containing substance to contact and react with said chlorine and sulfur removal agent to form at least one of harmless chloride and sulfite. S*

20. An apparatus as claimed in claim 19, wherein said S* chlorine and sulfur removal agent contains at least one Sr ro compound selected from the group consisting of carbonate, hydrogen carbonate, and hydroxide of at least one element *SSS selected from the group consisting of sodium and potassium, said carbonate being other than sodium S carbonate. S

21. An apparatus as claimed in claim 19, wherein said chlorine and sulfur removal agent contains at least one compound selected from the group consisting of sodium Shydrogen carbonate, sodium sesqui carbonate, natural -72- soda, sodium hydroxide, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, and potassium sodium carbonate.

22. A process for removing a noxious component from a treatable material containing the noxious component, said process being substantially as herein described.

23. A noxious component removal agent to be used in a process for removing noxious component from a treatable material containing the noxious component, said process being substantially as herein described.

24. An apparatus for removing at least one of chlorine and sulfur from a treatable material containing the said chlorine and sulfur, said apparatus being substantially as herein described with reference to and as illustrated in the accompanying drawing. Dated this 3rd day of November 1999 KARTTSHTKT KAISHA MEIDENSHA By their Patent Attorneys GRIFFITH HACK .9 9 9