Methods for treating persistent organic pollutants

Abstract

This invention provides a method for decomposing POPs while introducing them from the tail end of a cement kiln, which is at a lower temperature than the front end. [Solution] This processing method uses a cement clinker manufacturing facility having a cement kiln, an upper cyclone, a rising duct, a calcination furnace including a calcination burner, and a bottom cyclone. The bottom cyclone separates the gas containing powder that has passed through the calcination furnace and rising duct into solid and gas components, discharging the gas component to the upper cyclone from the gas outlet and sending the solid component to the kiln end from the solid outlet. The material to be processed, which contains persistent organic pollutants, is introduced from at least one of the kiln end, the rising duct, and the calcination furnace, the temperature at the kiln end is set to 1050°C or higher, and the temperature at the gas outlet of the bottom cyclone is set to 770°C or higher.

Description

[Technical Field]

[0001] The present invention relates to a method for treating persistent organic pollutants. [Background technology]

[0002] Persistent organic pollutants (POPs) are substances that are difficult to decompose in the environment, easily accumulate in living organisms, can travel long distances, and can be harmful to human health. Due to concerns about global pollution by POPs, the Stockholm Convention on Persistent Organic Pollutants (POPs Convention) was adopted and came into effect in May 2004.

[0003] POPs include dioxins, PCBs (polychlorinated biphenyls), DDT, and PFAS (perfluoroalkyl substances and polyfluoroalkyl compounds). High-temperature heat treatment is known to be an effective method for decomposing these substances.

[0004] The applicant has previously proposed a method to suppress the generation of dioxins by heat-treating fermented municipal solid waste using a cement kiln (see Patent Document 1 below). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-199584 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The method described in Patent Document 1 involves separating the fermented municipal solid waste into coarse particles with a high calorific value containing a large amount of waste plastics, etc., and fine particles with a low calorific value. The coarse particles are fed in from the kiln burner, and the fine particles are fed in from the rear of the kiln. The coarse particles contain waste plastics, etc., and by being fed in from the front of the kiln, they can be burned at the high temperature inside the cement kiln, thus suppressing the generation of POPs.

[0007] However, in the method described in Patent Document 1, the fine components of the municipal solid waste are introduced from the kiln's tail end. The tail end is located away from the front end where the burner is installed, and is therefore at a lower temperature than the front end. As a result, there remains a possibility that persistent organic pollutants contained in the fine components will not be decomposed and will be discharged mixed with the kiln exhaust gas.

[0008] In view of the above problems, the present invention aims to provide a method for decomposing POPs while introducing them from the tail end of the cement kiln, which is at a lower temperature than the front end of the kiln. Here, "tail end" refers to the tail end of the cement kiln and upstream of the tail end in the direction of flow of the cement raw materials. [Means for solving the problem]

[0009] The method for treating persistent organic pollutants according to the present invention is: A method using cement clinker manufacturing equipment, The aforementioned cement clinker manufacturing facility is Cement kiln and, The upper cyclone into which the cement raw materials are fed, A rising duct connected to the kiln end of the cement kiln, A calcination furnace, including a calcination burner, into which the cement raw material is introduced from the upper cyclone, The furnace and the rising duct are provided with a bottom cyclone which separates the gas containing powder that has passed through them into solid and gas components, discharges the gas component from the gas outlet, and sends the solid component from the solid outlet through the bottom raw material chute to the end of the furnace. The material to be treated, containing persistent organic pollutants, is introduced from at least one of the kiln end, the rising duct, and the calcination furnace. The temperature of the kiln's tail section is set to 1,050°C or higher. The bottom cyclone is characterized by setting the temperature of the gas outlet to 770°C or higher.

[0010] The method for treating persistent organic pollutants according to the present invention is: A method using cement clinker manufacturing equipment, The aforementioned cement clinker manufacturing facility is Cement kiln and, The upper cyclone into which the cement raw materials are fed, The cement raw material is introduced from the upper cyclone and connected to a rising duct at the bottom of the cement kiln, The system includes a bottom cyclone that separates the gas containing powder that has flowed through the rising duct into solid and gas components, discharges the gas component from the gas outlet to the upper cyclone, and sends the solid component to the end of the kiln through the bottom raw material chute. The material to be treated, containing persistent organic pollutants, is introduced from at least one of the kiln end and the rising duct. The temperature of the kiln's tail section is set to 1,170°C or higher. Another feature is that the temperature of the gas outlet of the bottom cyclone is set to 690°C or higher.

[0011] In this invention, "persistent organic pollutants" refers to substances known as POPs, which are defined in the POPs Convention. Typically, POPs include PFAS, dioxins, DDT, and PCBs. PFAS are organofluorine compounds belonging to POPs, and are a general term for perfluoroalkyl compounds and polyfluoroalkyl compounds. Typical PFAS include PFOS (perfluorooctanesulfonic acid), PFOA (perfluorooctanoic acid), PFHxS (perfluorohexanesulfonic acid), and PFNA (perfluorononanoic acid). In Japan, regulatory limits have been set for PFOS and PFOA. For example, in the United States, standard concentrations for PFHxS and PFNA in drinking water have also been set. Therefore, it is possible that regulatory limits for PFHxS and PFNA will also be set in Japan in the future.

[0012] As described above, in the treatment method according to the present invention, the material to be treated, which contains persistent organic pollutants, is introduced from at least one of the following locations: the tail end of the cement kiln, the rising duct, and the calcination furnace, or from at least one of the following locations: the tail end of the cement kiln and the rising duct.

[0013] According to the "Technical Considerations Regarding the Treatment of PFOS and PFOA-Containing Waste" (hereinafter abbreviated as "Ministry of the Environment document") published by the Ministry of the Environment in September 2022, examples of waste containing PFAS include fire extinguishing foam, containers that hold PFAS-containing materials, and cloths used to wipe up PFAS-containing washing water. Furthermore, since technologies for concentrating, separating, and recovering PFAS using activated carbon and anion exchange resins are known, waste materials such as activated carbon and resins used in these treatments are also considered to be PFAS-containing waste.

[0014] According to the above-mentioned Ministry of the Environment document, for PFOS, treatment at about 850°C or higher for 2 seconds or more is recommended, and for PFOA, treatment at about 1,000°C or higher for 2 seconds or more is recommended. PFOS and PFOA are representative substance groups of PFAS, and there is no mention of other substances in this Ministry of the Environment document. However, if in accordance with the stricter of these standards, it is considered that for treating PFAS, treatment at about 1,000°C or higher for 2 seconds or more is recommended. Also, even when viewed in the broad concept of POPs, it is speculated that if the treatment target containing POPs can be treated at about 1,000°C or higher for 2 seconds or more, the decomposition treatment of POPs is possible.

[0015] As a method of treating the treatment target containing POPs in the high-temperature environment as described above, a method of treating in a general incineration plant (incinerator) can be considered. However, in the treatment in a general incineration plant, incineration residues (main ash, fly ash) are generated, and this becomes secondary waste. This secondary waste is usually subjected to landfill treatment.

[0016] As another method of treating the treatment target containing POPs in the high-temperature environment as described above, a method using the cement manufacturing process can be considered. In the cement manufacturing process, it is treated at a high temperature of about 1,450°C, and the incineration residue is incorporated into the clinker and no secondary waste is generated. Therefore, conventionally, it has been used in technologies for converting waste such as waste plastics and waste tires into raw fuels. However, in cement clinker manufacturing facilities, there are many regions (equipment, piping) that show different temperatures depending on the location, and also the wind speed of the gas flowing through the equipment and piping is fast in some locations. Therefore, even if the cement manufacturing process is used to treat the treatment target containing POPs, it is necessary to carefully consider in which region of the cement clinker manufacturing facility the treatment target should be input.

[0017] In view of processing an object to be processed containing POPs using a cement kiln, as described above, considering the ease of realizing the temperature environment recommended as the decomposition treatment, a method of charging the object to be processed from the front part of the kiln can be considered. In particular, since a kiln burner is attached to the front part of the kiln, an extremely high-temperature environment is constructed by the flame from the kiln burner. Further, since an air flow is generated in the cement kiln from the front part of the kiln toward the rear part of the kiln, the decomposition time can be ensured while being conveyed in this air flow. From the above viewpoints, if the object to be processed can be charged from the front part of the kiln, it seems possible to decompose POPs such as PFAS contained in the object to be processed.

[0018] However, since the front part of the kiln is close to the clinker discharge location, when charging the object to be processed from the front part of the kiln, it is necessary to perform pretreatment such as crushing on the object to be processed so as not to affect the quality of the clinker. Further, in view of the influence on the flame of the main fuel blown from the kiln burner, it is difficult to charge a liquid or slurry-like object to be processed.

[0019] As exemplified above, various forms are assumed as the object to be processed containing persistent organic pollutants (POPs) typified by PFAS, such as foam extinguishers, containers, fabrics, activated carbon, resins, and the like. Further, it may be assumed that a liquid or slurry containing POPs is to be processed. That is, from the viewpoint of processing objects to be processed with various loading forms, the front part of the kiln is not the most optimal as the charging location of the object to be processed.

[0020] On the other hand, regarding the rear part of the kiln and the downstream side of the rear part of the kiln with respect to the air flow direction, since it is away from the clinker discharge location and the installation location of the kiln burner, the requirements regarding the loading form of the object to be processed, such as in the case of charging to the front part of the kiln, are relaxed.

[0021] However, since the downstream side of the rear part of the kiln with respect to the rear part of the kiln and the air flow direction is lower in temperature than the front part of the kiln, it is unclear whether the recommended conditions of treatment at about 1,000 °C or higher for 2 seconds or more can be ensured.

[0022] According to the inventor's diligent research, when the temperature at the bottom of the kiln is set to 1,050°C or higher, and the temperature at the gas outlet of the bottom cyclone is set to 770°C or higher, the POPs concentration in the gas discharged from the gas outlet of the bottom cyclone is 60 ng / Nm³. 3 We found that it could be suppressed to less than 60 ng / Nm³. Furthermore, even when the temperature at the bottom of the kiln was set to 1,170°C or higher and the temperature at the gas outlet of the bottom cyclone was set to 690°C or higher, the POPs concentration in the gas discharged from the gas outlet of the bottom cyclone could be suppressed to less than 60 ng / Nm³. 3 We found that it could be suppressed to less than [amount missing].

[0023] Further details will be provided later in the section on "Modes for Carrying Out the Invention," but the above results were derived from verification. This verification was conducted under conditions where cement clinker was calculated at 165 t-clinker / h, and pure substances containing equal amounts of PFOA and PFOS were added at a rate of 16.93 kg / h. These conditions created an environment with an extremely high concentration of POPs and were more stringent than the conditions normally assumed.

[0024] On the other hand, according to the above-mentioned Ministry of the Environment document, the reference management target value for exhaust gas, assuming a concentration of PFOS, PFOA, etc. in the waste (material to be treated) is 10,000 mg / kg, is 60 ng / Nm³. 3 This is the setting. In contrast, the above verification assumes that the treated material is a pure substance containing equal amounts of PFOA and PFOS, and is therefore stricter than the conditions in the Ministry of the Environment document.

[0025] Furthermore, as mentioned above, if the temperature at the bottom of the kiln is set to 1,050°C or higher, and the temperature at the gas outlet of the bottom cyclone is set to 770°C or higher, the POPs concentration in the gas discharged from the gas outlet of the bottom cyclone should be set to 60 ng / Nm³ 3The level has been suppressed to below 60 ng / Nm³, and this value meets the reference value for management targets described in the Ministry of the Environment document. Similarly, when the temperature at the bottom of the kiln is set to 1,170°C or higher and the temperature at the gas outlet of the bottom cyclone is set to 690°C or higher, the POPs concentration in the gas discharged from the gas outlet of the bottom cyclone is kept below 60 ng / Nm³. 3 The level was kept below a certain threshold, and this value meets the reference value for management targets described in the Ministry of the Environment document. Furthermore, as mentioned above, this verification was conducted under extremely strict conditions. Therefore, when using the cement clinker manufacturing process to introduce materials to be treated, such as foam fire extinguishing agents, containers, cloths, activated carbon, and resins, which contain POPs rather than pure substances, from a separate inlet from the cement raw materials, it is suggested that POPs, such as PFAS, can be decomposed by setting the temperature conditions described above, even if the inlet is not at the front of the kiln.

[0026] As described above, the input points for the materials to be processed are not the front of the kiln, but the rear of the kiln, the rising duct, or the firing furnace, allowing for greater flexibility in packaging. Specifically, materials to be processed, including POPs, can be solids such as activated carbon, containers, and cloths; liquids such as foam extinguishing agents and POPs washing solutions; and slurry-like sludge. Furthermore, if the materials to be processed are solids, even large lumps can be input, and pre-treatment such as crushing is unnecessary.

[0027] If the material to be treated is solid, a predetermined amount may be introduced through an inlet installed at a designated location. If the material to be treated is liquid, it may be introduced through a pipe installed at a designated location, or it may be sprayed using a spray nozzle.

[0028] Furthermore, to increase the decomposition time of POPs, or to prevent dust dispersion and improve handling, the materials to be processed can be mixed with alternative raw materials (e.g., incinerator ash, cut tires, round tires, clay raw materials, sewage sludge, clay slurry, etc.) before being introduced into the system.

[0029] The amount of persistent organic contaminants contained in the treated material may be set to be greater than 0 and 100 g / t-clinker or less per unit of raw material.

[0030] The concentration of persistent organic pollutants in the treated material may be 5.0 μg / kg or more. However, the concentration of persistent organic pollutants in the treated material is preferably 3.0 μg / kg or less.

[0031] The rising duct has a first inlet located closer to the side surface on the cement kiln side than the central axis of the rising duct, and located above the top of the connection point between the cement kiln and the kiln tail by a length less than or equal to the inner diameter of the cement kiln. The material to be processed may be introduced at least through the first input port.

[0032] The rising duct (also called a "riser duct") is connected to the tail end of the cement kiln, and kiln combustion gases discharged through the tail end flow through it. Although the cement kiln is tilted at a slight angle (generally about 1.5° to 3.5°), it essentially extends horizontally. On the other hand, the rising duct extends mostly vertically. Therefore, when the kiln combustion gases discharged from the cement kiln reach the tail end, inertial force causes them to predominantly travel on the side of the rising duct away from the kiln (the side furthest from the cement kiln). As a result, a region of kiln combustion gas accumulation is created on the kiln side of the rising duct. Therefore, by introducing the material to be processed into this region, it becomes easier to ensure that the material remains in a high-temperature environment for a sufficient amount of time. This, in turn, ensures sufficient decomposition time for POPs.

[0033] The kiln bottom section has a second input port located within 4 meters of the connection port of the bottom raw material chute. The material to be processed may be introduced at least through the second input port.

[0034] According to the above method, the cement raw materials (bottom raw materials) introduced into the kiln through the bottom raw material chute and the material to be processed are more easily mixed inside the kiln's tail section. As a result, the material to be processed is more easily carried into the cement kiln along with the flow of the bottom raw materials, making it easier to ensure that the material to be processed remains in a high-temperature environment for a sufficient amount of time. This ensures that POPs have enough time to decompose.

[0035] The aforementioned furnace has a third input port located within 5 m of the end of the aforementioned burner, The material to be processed may be introduced at least through the third input port.

[0036] According to the method described above, the object to be processed can be introduced into the high-temperature environment created by the flame of the incinerator, making it easier to ensure that the object remains in the high-temperature environment for a sufficient amount of time. As a result, sufficient time can be secured for the decomposition of POPs.

[0037] In particular, when the calcination burner is mounted vertically, it is preferable that the material to be processed is introduced into the calcination furnace in a direction substantially parallel to the mounting direction of the calcination burner (with an angle of 10° or less between the two). This prevents the material to be processed from crossing the flame of the calcination burner, thereby ensuring the stability of the flame formed by the calcination burner.

[0038] There are no particular restrictions on the type of calcination furnace used; for example, SF calcination furnaces, MFC calcination furnaces, RSP calcination furnaces, KSV calcination furnaces, DD calcination furnaces, SLC calcination furnaces, etc., can be used. [Effects of the Invention]

[0039] The present invention provides a method for disassembling and processing objects containing POPs while reducing restrictions on the packaging. [Brief explanation of the drawing]

[0040] [Figure 1]This is a schematic diagram showing one form of cement clinker manufacturing equipment used in implementing the method for treating persistent organic pollutants of the present invention. [Figure 2] This is a schematic diagram showing an enlarged portion of Figure 1, illustrating a suitable installation location for the first inlet 21 provided in the rising duct 4. [Figure 3] This is a schematic diagram showing another form of cement clinker manufacturing equipment used in implementing the method for treating persistent organic pollutants of the present invention. [Figure 4] This is a schematic diagram showing an enlarged portion of Figure 3, illustrating the preferred installation position of the second input port 22 provided at the kiln's tail section 12. [Figure 5] This is a schematic diagram showing an enlarged portion of Figure 3, illustrating the preferred installation position of the second input port 22 provided at the kiln's tail section 12. [Figure 6] This is a schematic diagram showing another form of cement clinker manufacturing equipment used in implementing the method for treating persistent organic pollutants of the present invention. [Figure 7] This is a schematic diagram showing an enlarged portion of Figure 6, illustrating a suitable installation location for the third input port 23 provided in the calcination furnace 5. [Figure 8] This diagram shows a modified version of Figure 6, schematically illustrating only a portion of the structure. [Figure 9] Figure 8 is a schematic diagram showing the positional relationship between the calcination burner 7 and the third input port 23 in the calcination furnace 5. [Figure 10] This is a schematic diagram showing another form of cement clinker manufacturing equipment used in implementing the method for treating persistent organic pollutants of the present invention. [Figure 11] This is a schematic diagram showing another form of cement clinker manufacturing equipment used in implementing the method for treating persistent organic pollutants of the present invention. [Figure 12] This is a cross-sectional view of the structure of the 3D model used for verification. [Figure 13] This is a perspective view of the structure of the 3D model used for verification. [Figure 14] Figure 12 shows the simulation results illustrating the flow of gas GA, introduced from the kiln-end inlet 2a of cement kiln 2, through the rising duct 4, using the 3D model. [Modes for carrying out the invention]

[0041] Embodiments of the method for treating persistent organic pollutants according to the present invention (hereinafter abbreviated as "this treatment method") will be described below with reference to the drawings. The following drawings are schematic representations, and the dimensional ratios in the drawings do not necessarily match the actual dimensional ratios, nor do the dimensional ratios between the drawings necessarily match.

[0042] Figure 1 is a schematic diagram showing one form of cement clinker manufacturing equipment used in the implementation of this processing method. The cement clinker manufacturing equipment 1 comprises a cement kiln 2 with a kiln burner 8 installed on the front end 11, an upper cyclone 3 into which cement raw materials are fed, a rising duct 4 connected to the rear end 12 of the cement kiln 2, a calcination furnace 5 including a calcination burner 7, and a bottom cyclone 6 connected to the calcination furnace 5. The rising duct 4 is a pipe that extends vertically and is sometimes referred to as a "riser duct".

[0043] The cement raw material, preheated by passing through the upper cyclone 3 (which consists of one or more stages), is introduced into the calcination furnace 5. In the structure of the cement clinker manufacturing facility 1 shown in Figure 1, the cement raw material introduced into the calcination furnace 5 is calcined as it rises along with the flow of kiln combustion gas rising in the rising duct 4. After that, the calcined cement raw material is sent to the bottom cyclone 6 by gas for solid-gas separation. Solid components are discharged from the solid outlet 6a of the bottom cyclone 6, and gaseous components are discharged from the gas outlet 6b.

[0044] In the cement clinker manufacturing facility 1 shown in Figure 1, the gas outlet 6b of the bottom cyclone 6 is connected to the upper cyclone 3, and the gas obtained by solid-gas separation in the bottom cyclone 6 is sent to the upper cyclone 3 and used for preheating the cement raw materials. On the other hand, the solid outlet 6a is connected to the kiln end 12 through the bottom raw material chute 14. As a result, the cement raw materials decarboxylated by the calcination furnace 5 are introduced into the kiln end 12 from the bottom raw material chute 14 and then sent into the cement kiln 2. Then, cement clinker is produced by high-temperature firing of this cement raw material in the cement kiln 2. After that, the cement clinker is cooled in the clinker cooler 13 and discharged.

[0045] The cement clinker manufacturing facility 1 shown in Figure 1 is equipped with a first inlet 21 in the rising duct 4 for introducing the material to be treated P1 (see Figure 2, described later) containing persistent organic contaminants. The material to be treated P1 may be in solid, liquid, or slurry form. The material to be treated P1 is not limited to materials containing persistent organic contaminants (POPs) such as PFAS, but examples include foam fire extinguishing agents, containers, cloths, activated carbon, and resins.

[0046] Furthermore, the persistent organic pollutants (POPs) contained in the treated material P1 are substances defined in the POPs Convention and typically include PFAS, dioxins, DDT, and PCBs. PFAS typically include PFOS, PFOA, PFHxS, and PFNA.

[0047] The temperature of the furnace end section 12 is set to 1,050°C or higher, and the temperature of the gas outlet 6b of the bottom cyclone 6 is set to 770°C or higher. As a result, POPs contained in the material to be processed P1, which is introduced from the first inlet 21, are decomposed as they pass through the rising duct 4, reach the bottom cyclone 6, and are discharged from the gas outlet 6b, thereby suppressing the concentration of POPs in the gas discharged from the gas outlet 6b to below the standard value. This point will be described later with reference to the examples.

[0048] Furthermore, if the temperature of the kiln's rear section 12 is set to 1,170°C or higher, the temperature of the gas outlet 6b of the bottom cyclone 6 only needs to be set to 690°C or higher.

[0049] Figure 2 is a schematic diagram showing an enlarged portion of Figure 1, illustrating the preferred installation position of the first inlet 21 provided in the rising duct 4. As shown in Figure 2, the first inlet 21 is preferably provided on the side closer to the cement kiln 2 than the central axis 4a of the rising duct 4, with respect to the central axis 4a. Furthermore, the entire first inlet 21 is preferably located at a distance of no more than D from the top 12A of the connection point between the cement kiln 2 and the kiln bottom 12, when the inner diameter of the cement kiln 2 is D. In Figure 2, the preferred region of the first inlet 21 formed in the rising duct 4 is indicated by hatching in the region between horizontal line A1 and horizontal line A2. Horizontal line A1 is a line indicating the height position of the top 12A, and horizontal line A2 is a line indicating a position shifted vertically upward by the inner diameter D of the cement kiln 2 from horizontal line A1.

[0050] As described above, an upward airflow of kiln combustion gas discharged from the cement kiln 2 is formed within the rising duct 4. In this region, within the rising duct 4, a portion of the kiln combustion gas discharged from the cement kiln 2 accumulates in a location close to the kiln tail 12 in the vertical direction and close to the cement kiln 2 in the horizontal direction, creating a region with a slower gas flow velocity. This point will be explained later with reference to Figure 14.

[0051] As shown in Figure 2, the material to be processed P1, including POPs, is introduced into the rising duct 4 through the first inlet 21. As a result, the area where it is introduced is a region where the flow velocity of the high-temperature kiln combustion gas is relatively slow and the gas is stagnant, as described above. Consequently, the material to be processed P1 is exposed to a high-temperature environment for a sufficient amount of time, ensuring that the POPs have time to decompose.

[0052] Figure 3 is a schematic diagram showing another configuration of the cement clinker manufacturing equipment used in implementing this processing method. The cement clinker manufacturing equipment 1 shown in Figure 3 differs from the cement clinker manufacturing equipment 1 shown in Figure 1 in that, instead of the first inlet 21, a second inlet 22 is provided at the kiln end 12 for introducing the material to be processed P1 (see Figures 4-5 described later), which includes POPs. Otherwise, it is the same.

[0053] As described above, cement raw material M1 (see Figures 4-5 described later) is introduced into the kiln end 12 from the solid discharge port 6a of the bottom cyclone 6 through the bottom raw material chute 14. This cement raw material M1 flows into the cement kiln 2 from the kiln end 12 and is fired. As shown in Figure 3, when the material to be processed P1 is introduced from the second input port 22, some of the POPs contained in the material to be processed P1 are gasified or atomized by the high-temperature kiln combustion gas flowing from the cement kiln 2 towards the kiln end 12 and pass through the rising duct 4. Then, they are decomposed between the rising duct 4 and the gas discharge port 6b of the bottom cyclone 6. In addition, some of the material to be processed P1 flows into the cement kiln 2 along with the flow of cement raw material. Because the inside of the cement kiln 2 is extremely hot, the POPs contained in the material to be processed P1 are gasified or atomized by being exposed to the high-temperature environment and sent to the rising duct 4 along with the flow of kiln combustion gas. Subsequently, the gasified POPs are decomposed as they travel from the rising duct 4 to the gas outlet 6b of the bottom cyclone 6.

[0054] As described above, the temperature of the kiln's rear section 12 is set to 1,050°C or higher, and the temperature of the gas outlet 6b of the bottom cyclone 6 is set to 770°C or higher. Alternatively, the temperature of the kiln's rear section 12 is set to 1,170°C or higher, and the temperature of the gas outlet 6b of the bottom cyclone 6 is set to 690°C or higher.

[0055] In the cement clinker manufacturing facility 1 shown in Figure 1, the material to be processed P1 is introduced into the rising duct 4 via the first inlet 21. In contrast, in the cement clinker manufacturing facility 1 shown in Figure 3, the material to be processed P1 is introduced into the kiln end 12. Subsequently, when the POPs contained in the material to be processed P1 are gasified or atomized, the gas containing the POPs passes through the rising duct 4. In other words, compared to introducing the material to be processed P1 into the rising duct 4 via the first inlet 21, introducing the material to be processed P1 into the kiln end 12 via the second inlet 22 allows for a longer period of exposure of the POPs contained in the material to be processed P1 to a high-temperature environment.

[0056] Figures 4 and 5 are schematic diagrams that are enlarged portions of Figure 3 and illustrate the preferred installation position of the second inlet 22 provided in the kiln end 12. As shown in Figures 4 and 5, the second inlet 22 is preferably installed at a position where the distance d1 from the connection port between the bottom raw material chute 14 and the kiln end 12 is within 4 m, i.e., within 4 m from the end 14a of the bottom raw material chute 14. By introducing the material to be processed P1 near the end 14a of the bottom raw material chute 14 in this way, the cement raw material M1 introduced from the bottom raw material chute 14 and the material to be processed P1 are more easily mixed inside the kiln end 12. This makes it easier for the material to be processed P1 to enter the inside of the cement kiln 2 on the flow of the cement raw material M1, and makes it easier to secure time to remain in a high-temperature environment. As a result, time for the decomposition of POPs can be secured. The distance d1 from the end 14a of the bottom raw material chute 14 is more preferably within 2 m, and particularly preferably within 1 m.

[0057] Figure 4 shows the case where the bottom raw material chute 14 is inserted through the front or back of the kiln end 12 when the longitudinal direction of the cement kiln 2 is viewed from left to right. Figure 5 shows the case where the bottom raw material chute 14 is inserted through the side of the kiln end 12 that is furthest from the cement kiln 2 when the longitudinal direction of the cement kiln 2 is viewed from left to right.

[0058] The material to be processed P1 may be introduced from the second inlet 22 in a state mixed with alternative raw materials (e.g., incinerator ash, cut tires, round tires, clay raw materials, sewage sludge, clay slurry, etc.). This is expected to prevent dust scattering, improve the handling of the material to be processed P1, and further ensure the decomposition time of POPs. The same applies when the material to be processed P1 is introduced into the rising duct 4 through the first inlet 21, as shown in Figures 1 and 2.

[0059] Figure 6 is a schematic diagram showing another configuration of the cement clinker manufacturing equipment used in implementing this processing method. The cement clinker manufacturing equipment 1 shown in Figure 6 differs from the cement clinker manufacturing equipment 1 shown in Figure 1 in that, instead of the first input port 21, a third input port 23 is provided in the calcination furnace 5 for introducing the material to be processed P1 (see Figures 7 to 9 described later), which includes POPs. Otherwise, it is the same.

[0060] The calcination furnace 5 has a calcination burner 7, and a high-temperature environment is created when fuel is burned by the calcination burner 7 and a flame is formed. Therefore, when the material to be processed P1 is introduced into the calcination furnace 5, some or all of the POPs can be decomposed within the calcination furnace 5.

[0061] Furthermore, as described above with reference to Figure 1, the cement raw material introduced into the calcination furnace 5 from the upper cyclone 3 rises along with the flow of kiln combustion gas rising in the rising duct 4, is calcined, and is then sent to the bottom cyclone 6 for solid-gas separation. In other words, the material to be processed P1 introduced into the calcination furnace 5 via the third inlet 23 is gasified by being placed in an extremely high-temperature environment in the calcination furnace 5, and this gas is then sent to the bottom cyclone 6 along with the flow of kiln combustion gas rising in the rising duct 4.

[0062] In other words, compared to the case where the material to be processed P1 is introduced into the rising duct 4 via the first inlet 21, introducing the material to be processed P1 into the incinerator 5 via the third inlet 23 ensures a longer exposure time to the temperature environment necessary for the decomposition of POPs contained in the material to be processed P1.

[0063] Figure 7 is a schematic diagram showing an enlarged portion of Figure 6, illustrating a suitable installation location for the third input port 23 provided in the calcination furnace 5. As shown in Figure 7, the third input port 23 is preferably installed at a position where the distance d2 from the end 7a of the calcination burner 7 is within 5 m. By introducing the material to be processed P1 near the end 7a of the calcination burner 7 in this way, the material to be processed P1 is introduced into the high-temperature environment region formed by the flame of the calcination burner 7, thereby ensuring a longer exposure time to the temperature environment necessary for the decomposition of POPs.

[0064] Figure 6 illustrates a structure in which the calcination burner 7 is installed in a nearly horizontal direction. In contrast, as shown in Figures 8 and 9, the calcination burner 7 may be installed in the calcination furnace 5 to form a flame directed vertically downward. In this case, it is preferable that the third inlet 23 is installed so that the material to be processed P1 is introduced in a direction substantially parallel to the calcination burner 7 (the angle between the two is 10° or less). This prevents the material to be processed P1 from crossing the flame formed by the calcination burner 7, thereby ensuring the stability of the flame. Furthermore, even if the material to be processed P1 swirls in the calcination furnace 5 and volatilizes as a gas, it will merge into the lower part of the rising duct 4 through the piping, thus ensuring a longer exposure time to the temperature environment necessary for the decomposition of POPs.

[0065] In the above explanation, it was assumed that the gas discharged from the furnace 5 is sent to the bottom cyclone 6, but it may also be sent to a location other than the bottom cyclone 6 (see Figures 10 and 11).

[0066] Figure 10 shows a modified version of the cement clinker manufacturing equipment 1 shown in Figure 1, which is equipped with a separate calcination furnace cyclone 31. In the cement clinker manufacturing equipment 1 shown in Figure 10, the cement raw materials introduced into the calcination furnace 5 are sent to the calcination furnace cyclone 31 on the flow of calcination furnace combustion gas discharged from the calcination furnace 5, where they undergo solid-gas separation. In Figure 1, although not shown, a combustion-supporting gas is introduced into the calcination furnace 5, and this gas is used for combustion in the calcination burner 7 and discharged from the calcination furnace 5 as calcination furnace combustion gas.

[0067] The solid component of the calcined cement raw material, separated into solid and gas components in the calcination furnace cyclone 31, is sent to the bottom raw material chute 14 and the rising duct 4. The cement raw material sent to the rising duct 4 is carried by the flow of kiln combustion gas rising within the rising duct 4 to the bottom cyclone 6, where it is separated into solid and gas components. Meanwhile, the gaseous component of the calcination furnace combustion gas, separated into solid and gas components in the calcination furnace cyclone 31, flows through a separate piping system from the kiln combustion gas flowing through the rising duct 4. Since this calcination furnace combustion gas has a high CO2 concentration, CO2 separation and recovery may be performed at a later stage.

[0068] In the example shown in Figure 10, a first inlet 21 for introducing the material to be processed P1 into the rising duct 4 is provided. However, as described above with reference to Figure 3, a second inlet 22 for introducing the material to be processed P1 into the kiln tail section 12 may also be provided.

[0069] Figure 11 shows a further modification of the cement clinker manufacturing equipment 1 shown in Figure 10, which is further equipped with a calcination furnace duct 41. In this configuration, as described above with reference to Figures 8 to 9, the calcination furnace 5 has a calcination burner 7 that forms a flame in the vertical direction. In the cement clinker manufacturing equipment 1 shown in Figure 11, the cement raw material introduced into the calcination furnace 5 is discharged from the calcination furnace 5 and then sent to the calcination furnace duct 41. Gas flows into the calcination furnace duct 41 through the piping 42, forming an upward airflow within the calcination furnace duct 41. The cement raw material is carried by this airflow to the calcination furnace cyclone 31, where it is separated into solid and gas. The gas flowing into the calcination furnace duct 41 through the piping 42 is set to a high temperature so as not to hinder the calcination of the cement raw material, and to create a temperature environment in the calcination furnace duct 41 that is similar to that inside the calcination furnace 5. Preferably, the gas has a high CO2 concentration.

[0070] If the cement clinker manufacturing facility 1 is equipped with a calcination furnace 5, the type of calcination furnace 5 is arbitrary, and for example, calcination furnaces such as SF calcination furnaces, MFC calcination furnaces, RSP calcination furnaces, KSV calcination furnaces, DD calcination furnaces, and SLC calcination furnaces can be used.

[0071] In the example above, the cement clinker manufacturing equipment 1 was equipped with one of the following: a first inlet 21 for introducing the material to be processed P1 into the rising duct 4, a second inlet 22 for introducing the material to be processed P1 into the kiln end 12, and a third inlet 23 for introducing the material to be processed P1 into the calcination furnace 5. However, the cement clinker manufacturing equipment 1 may be equipped with two or more of the first inlet 21, the second inlet 22, and the third inlet 23.

[0072] The following details will be explained by referring to the simulation results.

[0073] Figures 12 and 13 are drawings of 3D models simulating the cement kiln 2, kiln end section 12, rising duct 4, firing furnace 5, and bottom cyclone 6, with Figure 12 being a cross-sectional view and Figure 13 being a perspective view.

[0074] The 3D models shown in Figures 12 and 13 simulate cement clinker manufacturing equipment 1 with the following dimensions. These dimensions are within the range of typical cement clinker manufacturing equipment.

[0075] • Kiln diameter of cement kiln 2: 5.3m • Inner diameter of Rising Duct 4: 2.2m • Horizontal distance between the side of the rising duct 4 opposite to the cement kiln 2 and the connection point between the cement kiln 2 and the kiln end 12: 3.4m • Vertical height of the rising duct 4, relative to the horizontal position of the connection point between cement kiln 2 and kiln end section 12: 1.6m

[0076] (Verification 1) The flow of gas GA introduced from the rear inlet 2a of cement kiln 2 through the rising duct 4 was verified using a fluid simulation with the 3D model described above. ANSYS Fluent 2020 R2 was used for the simulation. The results are shown in Figure 14.

[0077] According to Figure 14, within the rising duct 4, in the area closer to the kiln end 12 in the vertical direction, a region W1 was confirmed to be formed on the side facing the cement kiln 2 where the gas flow velocity was relatively slow and gas was stagnant. On the other hand, within the rising duct 4, it was confirmed that gas G1a with a relatively high flow velocity flowed on the side facing the cement kiln 2. Furthermore, the vertical height of this region W1 was approximately above the top 12A of the connection point between the cement kiln 2 and the kiln end 12 by a distance less than or equal to the kiln diameter D, with the top 12A being the reference point.

[0078] This is thought to be because, as the gas GA introduced from the kiln-end inlet 2a of cement kiln 2 approached the kiln-end section 12, inertial force caused the movement of the gas to become predominantly on the side opposite the kiln (the side furthest from cement kiln 2) within the rising duct 4. Furthermore, as shown in Figure 14, it was confirmed that the gas G1b retained in region W1 flowed upward at a relatively slower rate than the gas G1a.

[0079] In light of these results, it is considered that by introducing the material to be processed P1 into region W1, the time that the material to be processed P1 is exposed to a high-temperature environment is likely to be extended, and the decomposition time of POPs is likely to be secured. Therefore, as described above with reference to Figure 2, it is preferable that the first inlet 21 for introducing the material to be processed P1 into the rising duct 4 be located on the side closer to the cement kiln 2 than the central axis 4a of the rising duct 4, and at a distance of no more than D above the top of the connection point 12A between the cement kiln 2 and the kiln end 12.

[0080] (Verification 2) As examples of POPs, PFOA and PFOS, which belong to the PFAS group, were used, and their decomposition rates were measured in a tubular electric furnace. Based on the data obtained from these measurements, the leakage behavior of PFOA and PFOS contained in the exhaust gas was confirmed by fluid simulation when the treated material P1, which contains PFOA and PFOS, was introduced into the model shown in Figures 12 and 13. ANSYS Fluent 2020 R2 was used for the simulation. The levels and results are shown in Table 1 below.

[0081] [Table 1]

[0082] As described above, in this processing method, the rising duct 4 shown in Figure 1, the kiln end 12 shown in Figure 3, and the calcination furnace 5 shown in Figure 6 are assumed as destinations for introducing the material to be processed P1. Of these, it is understood that introducing the material to the rising duct 4 results in the most stringent conditions for POPs decomposition. This is because, as described above, whether the material to be processed P1 is introduced from the kiln end 12 or from the calcination furnace 5, the gas containing POPs passes through the rising duct 4. In other words, when the material to be processed P1 is introduced from the kiln end 12 or the calcination furnace 5, the time the gas containing POPs is exposed to a high-temperature environment is relatively longer compared to when the material to be processed P1 is introduced from the rising duct 4.

[0083] From this perspective, in this Verification 2, as shown in Figure 12, a model was considered in which a first inlet 21 is provided in the rising duct 4, and the material to be processed P1, including POPs, is introduced into the rising duct 4 from this first inlet 21. Based on Verification 1 described above, the first inlet 21 is a hypothetical horizontal plane located on the side closer to the cement kiln 2 than the central axis of the rising duct 4, when the kiln diameter of the cement kiln 2 is D, and at a distance of 0.3D above the top 12A of the connection point between the cement kiln 2 and the kiln end 12. The material to be processed P1 is then assumed to be introduced uniformly into the rising duct 4 from the first inlet 21, which is formed on this hypothetical horizontal plane.

[0084] When the material to be processed P1, including POPs, is introduced into one or more of the following locations: the rising duct 4, the kiln end 12, and the calcination furnace 5, various forms of the material P1 can be expected when introduced from these locations. Here, if a large lump of material P1 is introduced into any of the rising duct 4, the kiln end 12, or the calcination furnace 5, it will be carried by the high-temperature airflow and fall into the kiln end 12 and the cement kiln 2. After being left in the high-temperature environment for a certain period of time, it will become smaller in diameter, break down, or gasify, and rise through the rising duct 4 on the flow of kiln combustion gas. In other words, even when the material to be processed P1 is introduced from any of the rising duct 4, the kiln end 12, or the calcination furnace 5, it is expected that the particles or gasified POPs will flow through the rising duct 4 on the flow of kiln combustion gas.

[0085] In light of these circumstances, in this simulation, the material to be treated P1 was defined as particles with a diameter of Φ1 μm, and more specifically, particles consisting of pure substances containing equal amounts of PFOA and PFOS. This material P1 was then introduced into the rising duct 4 from a first inlet 21, which was a virtual horizontal plane, as described above. The input rate of the material P1 was set to 16.93 kg / h.

[0086] In this simulation, the input amount of cement raw material M1 was set so that cement clinker could be produced at a rate of 165 t / h. Here, the decomposition rate of cement raw material M1 was set to 30%, and the input amount of cement raw material M1 was set to 223 t / h. Furthermore, the input amount of the material to be processed, P1, mentioned above, which was 16.93 kg / h, is converted to an amount per ton of cement clinker, resulting in 103 g / t-clinker.

[0087] The set temperature of the kiln end section 12 was set to 1,170°C and 1,050°C, taking into consideration the temperature range during actual operation of cement clinker manufacturing equipment. In levels 1-1, 1-2, and 1-3, the set temperature of the kiln end section 12 was set to 1,170°C. In levels 2-1, 2-2, and 2-3, the set temperature of the kiln end section 12 was set to 1,050°C.

[0088] In the cases where the set temperature of the kiln end 12 was 1,170°C and 1,050°C, the amount of coal C1 fed into the calcination furnace 5 (see Figure 13) was reduced, thereby decreasing the amount of heat in the gas sent from the calcination furnace 5 to the rising duct 4. In levels 1-1, 1-2, and 1-3, the set temperature of the kiln end 12 was 1,170°C, but in level 1-2, the amount of coal C1 fed into the calcination furnace 5 was set to be less than in level 1-1, and in level 1-3, the amount of coal C1 fed into the calcination furnace 5 was set to be even less than in level 1-2. Similarly, in levels 2-1, 2-2, and 2-3, the set temperature of the kiln end 12 was 1,050°C, but in level 2-2, the amount of coal C1 fed into the calcination furnace 5 was set to be less than in level 2-1, and in level 2-3, the amount of coal C1 fed into the calcination furnace 5 was set to be even less than in level 2-2.

[0089] For each of the levels 1-1, 1-2, 1-3, 2-1, 2-2, and 2-3, the temperature of gas G1 discharged from the gas outlet 6b of the bottom cyclone 6, and the concentrations of PFOA and PFOS contained in gas G1 were derived by simulation. In Figure 13, the combustion-supporting gas introduced into the calcination furnace 5 is denoted by the symbol GB. The symbol M1 refers to the cement raw material.

[0090] According to Table 1, the concentrations of PFOS and PFOA in gas G1 discharged from gas outlet 6b of bottom cyclone 6 are 60 ng / Nm³. 3 Only level 2-3 exceeded the limit; the other levels (1-1, 1-2, 1-3, 2-1, 2-2) all had concentrations of PFOS, PFOA, etc. contained in gas G1 of 60 ng / Nm³. 3 The result was below average.

[0091] As mentioned above, according to the Ministry of the Environment document, the reference management target value for exhaust gas, assuming a concentration of PFOS, PFOA, etc. in the waste (materials to be treated) is 10,000 mg / kg, is 60 ng / Nm³. 3is set. In view of this, at levels 1-1, 1-2, 1-3, 2-1, and 2-2, the concentrations of PFOA and PFOS contained in gas G1 satisfy the regulatory conditions (less than 60 ng / Nm 3 ), and it is confirmed that PFOA and PFOS can be sufficiently decomposed.

[0092] On the other hand, at level 2-3, the concentrations of PFOA and PFOS contained in gas G1 did not satisfy the regulatory conditions. From the results of the measurement test of the decomposition rates of PFOA and PFOS using a tubular electric furnace, which was conducted prior to the simulation execution, it was confirmed that the decomposition rates of PFOA and PFOS at 700°C or lower are extremely slow compared to the decomposition rates in a higher temperature environment. Considering this fact, the temperature of gas G1 discharged from the gas outlet 6b of the bottom cyclone 6 was 680°C at level 2-3, and the temperature further decreases at a position downstream of the gas outlet 6b, it is expected that the concentrations of PFOA and PFOS contained in the exhaust gas discharged to the outside of the system under the conditions of level 2-3 are likely not to satisfy the regulatory conditions.

[0093] On the other hand, at levels 1-1, 1-2, 1-3, 2-1, and 2-2, since the concentrations of PFOA and PFOS contained in gas G1 at the time of discharge from the gas outlet 6b of the bottom cyclone 6 satisfy the regulatory conditions, it is considered that the concentrations of PFOA and PFOS contained in the exhaust gas discharged to the outside of the system also satisfy the regulatory conditions.

[0094] Note that at level 1-3, similar to level 2-3, the temperature of gas G1 discharged from the gas outlet 6b of the bottom cyclone 6 was 700°C or lower. However, unlike level 2-3, the concentrations of PFOA and PFOS contained in gas G1 satisfied the regulatory conditions. This is presumably because the set temperature of the kiln bottom part 12 was 1,170°C, which is higher than that of level 2-3, enabling the temperature environment during the flow through the rising duct 4 to be set to a high temperature suitable for decomposing PFOA and PFOS.

[0095] Based on the above, it is suggested that in order to achieve the concentration regulation of PFOA and PFOS contained in the exhaust gas, if the temperature of the kiln end 12 is relatively high at 1,170°C, the temperature of the gas G1 discharged from the gas outlet 6b of the bottom cyclone 6 needs to be set to 690°C or higher, and if the temperature of the kiln end is relatively low at 1,050°C, the temperature of the gas G1 discharged from the gas outlet 6b of the bottom cyclone 6 needs to be set to 770°C or higher.

[0096] Furthermore, since the decomposition rate of PFAS, including PFOA and PFOS, improves with higher temperatures, it is believed that the concentration of PFAS in the exhaust gas can be suppressed to below regulatory limits by setting the temperature of the kiln end 12 to 1,170°C or higher and the temperature of the gas G1 discharged from the gas outlet 6b of the bottom cyclone 6 to 690°C or higher, or by setting the temperature of the kiln end 12 to 1,050°C or higher and the temperature of the gas G1 discharged from the gas outlet 6b of the bottom cyclone 6 to 770°C or higher.

[0097] Furthermore, as mentioned above, this simulation was performed assuming that the material to be treated P1 consists of a pure substance containing equal amounts of PFOA and PFOS, and setting the input amount to 103 g / t-clinker (raw material unit). From this perspective, it is considered that if the input amounts of PFOA and PFOS contained in the material to be treated P1 are 103 g / t-clinker or less, more preferably 100 g / t-clinker or less, the concentration of PFAS contained in the exhaust gas at the time of discharge from the gas outlet 6b of the bottom cyclone 6 can be suppressed to below the regulatory limit.

[0098] As long as the above-described temperature environment is established, even if the cement clinker manufacturing facility 1 does not have a calcination furnace 5, it is considered that the PFAS contained in the material to be treated P1 can be decomposed by introducing the material to be treated P1 from either the rising duct 4 or the furnace end 12, thereby suppressing the concentration of PFAS in the exhaust gas to below the regulatory limit.

[0099] The above verification was conducted using PFOA and PFOS, because, at present, regulatory targets have only been set for PFOA and PFOS in Japan. POPs include PFAS other than PFOA and PFOS, as well as dioxins, DDT, and PCBs. While various types of POPs are expected to be accepted by cement clinker manufacturing facility 1 as the target material P1, by processing under the above temperature conditions, it is possible to decompose at least the PFOA and PFOS contained in the target material P1 within the limits that meet Japan's regulatory targets. Furthermore, given that it is subjected to extremely high temperatures, it is presumed that other PFAS, dioxins, DDT, and PCBs contained in the target material P1 can also be similarly decomposed. [Explanation of Symbols]

[0100] 1: Cement clinker manufacturing equipment 2: Cement Kiln 3: Upper Cyclone 4: Rising Duct 4a: Central axis of the rising duct 5: Kiln 6: Bottom Cyclone 6a: Solid outlet of bottom cyclone 6b: Gas outlet for bottom cyclone 7: Grilling burner 7a: End of the burner 8: Kilnburner 11: Front of the kiln 12: Kiln bottom 12A: Top of the connection point between the kiln end and the cement kiln 13: Klinka Cooler 14: Bottom raw material chute 14a: End of the bottom raw material chute (connecting port) 21:First input port 22:Second input port 23:Third input port 31: Cyclone for kiln 41: Duct for cauldron 42: Piping P1: Object to be processed

Claims

1. A method for treating persistent organic pollutants, The aforementioned processing method is a method using cement clinker manufacturing equipment, The aforementioned cement clinker manufacturing facility is Cement kiln and, The upper cyclone into which the cement raw materials are fed, A rising duct connected to the kiln end of the cement kiln, A calcination furnace, including a calcination burner, into which the cement raw material is introduced from the upper cyclone, The furnace and the rising duct are provided with a bottom cyclone which separates the gas containing powder that has passed through them into solid and gas components, discharges the gas component from the gas outlet, and sends the solid component from the solid outlet through the bottom raw material chute to the end of the furnace. The material to be treated, containing persistent organic pollutants, is introduced from at least one of the kiln end, the rising duct, and the calcination furnace. The temperature of the kiln's tail section is set to 1,050°C or higher. A method for treating persistent organic pollutants, characterized by setting the temperature of the gas outlet of the bottom cyclone to 770°C or higher.

2. A method for treating persistent organic pollutants, The aforementioned processing method is a method using cement clinker manufacturing equipment, The aforementioned cement clinker manufacturing facility is Cement kiln and, The upper cyclone into which the cement raw materials are fed, The cement raw material is introduced from the upper cyclone and connected to a rising duct at the bottom of the cement kiln, The system includes a bottom cyclone that separates the gas containing powder that has flowed through the rising duct into solid and gas components, discharges the gas component from the gas outlet to the upper cyclone, and sends the solid component to the end of the kiln through the bottom raw material chute. The material to be treated, containing persistent organic pollutants, is introduced from at least one of the kiln end and the rising duct. The temperature of the kiln's tail section is set to 1,170°C or higher. A method for treating persistent organic pollutants, characterized by setting the temperature of the gas outlet of the bottom cyclone to 690°C or higher.

3. The rising duct has a first inlet located closer to the side of the cement kiln than the central axis of the rising duct, and positioned above the top of the connection point between the cement kiln and the kiln tail by a length less than or equal to the inner diameter of the cement kiln. A method for treating persistent organic pollutants according to claim 1 or 2, characterized in that the substance to be treated is introduced at least from the first inlet.

4. The kiln bottom section has a second input port located within 4 meters of the connecting port of the bottom raw material chute. A method for treating persistent organic pollutants according to claim 1 or 2, characterized in that the substance to be treated is introduced at least from the second inlet.

5. The aforementioned furnace has a third input port located within 5 meters of the end of the aforementioned burner. A method for treating persistent organic pollutants according to claim 1 or 2, characterized in that the substance to be treated is introduced at least from the third input port.

6. The method for treating persistent organic pollutants according to claim 1 or 2, characterized in that the amount of persistent organic pollutants contained in the object to be treated is greater than 0 and 100 g / t-clinker or less per unit of raw material.

7. A method for treating persistent organic pollutants according to claim 1 or 2, characterized in that the concentration of persistent organic pollutants contained in the object to be treated is 5.0 μg / kg or more.

8. A method for treating persistent organic pollutants according to claim 1 or 2, characterized in that the persistent organic pollutants contained in the object to be treated are substances belonging to PFAS.

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