Incineration equipment management method and incineration system

Abstract

In an incineration facility for incinerating sewage sludge, a management method and an incineration system for an incineration facility that suppress the generation of ash deposits are realized. 【Solution means】 A management method for an incineration facility that incinerates sewage sludge, comprising an ash component identification step (#10) for identifying the concentrations of Ca element, Mg element, and P element in the incineration ash obtained by incinerating sewage sludge, and an index value calculation step (#11) for calculating an index value I represented by the following formula (1) based on the concentrations of each element identified in the ash component identification step (#10), and a chemical injection step (#12, #13) for injecting a chemical into the sewage sludge based on the index value I. Index value I: M P / (M P +M Ca +M Mg )···(1) Here, in formula (1), M P , M Ca , M Mg are exponents that depend on the concentrations of P element, Ca element, and Mg element, respectively.

Description

Technical Field

[0001] The present invention relates to a method for managing an incineration treatment facility and an incineration treatment system.

Background Art

[0002] When sewage sludge generated during the purification treatment of sewage at a sewage treatment plant is transported to an incineration treatment facility for incineration treatment. Specifically, the sewage sludge generated in the water treatment process of the sewage treatment plant is dehydrated sludge in the sludge treatment process and is transported to the incineration treatment facility. As shown in FIG. 11, as an example, the incineration treatment facility 10 includes a dehydrated sludge storage section 12 that receives and stores dehydrated sludge. The stored dehydrated sludge is discharged from the dehydrated sludge storage section 12 according to the incineration treatment situation in the incinerator 14 and is transported to the feeder 13. Then, the dehydrated sludge is introduced into the incinerator 14 from the feeder 13. After that, the dehydrated sludge incinerated in the incinerator 14 becomes exhaust gas mixed with incineration ash, and after the waste heat is recovered by the heat exchanger 15, the incineration ash is recovered in the dust collector 16 and the exhaust gas is sent to the flue gas treatment tower 18. The fly ash recovered by the dust collector 16 is sent to the ash storage section 17 for storage, and the exhaust gas is discharged outside the system after being treated in the flue gas treatment tower 18.

[0003] In such an incineration treatment facility for incinerating sewage sludge, the problem is that ash deposits occur inside the exhaust gas duct from the incinerator 14, the heat exchanger 15, and other equipment. Among them, ash deposits are likely to occur in the pipes inside the incinerator 14 and the pipes for transporting exhaust gas and the like from the incinerator 14 to the dust collector 16. In particular, ash deposits are likely to occur at bent portions, connection portions, etc. When such ash deposits adhere to the inside of the incineration treatment facility, not only is maintenance work required to remove the incineration ash, but the flue, which is the passage of the exhaust gas, is blocked, resulting in an emergency stop of the incineration treatment facility 10 and hindering the operation of the incinerator 14.

[0004] It is generally known that ash deposits in sewage sludge incineration facilities are generated when low-melting-point components in the incinerated ash melt and become liquid (liquid phase) during incineration, and then solidify. For example, Japanese Patent Publication No. 2015-213885 (Patent Document 1) proposes a method for evaluating the risk of blockage in an incinerator, comprising: a step of identifying the amount of phosphorus that can be bound to high-melting-point metal elements, which are multiple metal elements contained in sewage sludge that can form phosphorus compounds with melting points higher than the combustion temperature of the incinerator; a step of identifying the amount of phosphorus contained in the sewage sludge; and a step of calculating an evaluation index (blockage suppression index), which is the ratio of the amount of phosphorus that can be bound to to the amount of phosphorus contained in the sewage sludge. Reference Document 1 calculates the blockage suppression index X using a specific formula. Furthermore, Japanese Patent Publication No. 2010-12425 (Patent Document 2) proposes a method for predicting ash adhesion to a sewage sludge incineration treatment device using an index A calculated by a specific formula based on the composition of identified incinerated ash components. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-213885 [Patent Document 2] Japanese Patent Publication No. 2010-12425 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, when attempting to predict flue blockage in actual incineration facilities by identifying the concentrations of each element and calculating an index using the methods described in Patent Documents 1 and 2, it was found that blockage could not be predicted in many cases. This suggests that conventional evaluation indices still have room for improvement, and that the mechanisms of ash deposits and flue blockage caused by ash deposits are even more complex.

[0007] Therefore, there is a need for an incineration facility management method and incineration system that can improve the accuracy of predicting blockages in incineration facilities that incinerate sewage sludge, and suppress the generation of ash deposits compared to conventional technologies. [Means for solving the problem]

[0008] The method for managing an incineration facility according to the present invention is a method for managing an incineration facility that incinerates sewage sludge, wherein the incinerated ash obtained by incinerating the sewage sludge contains elements of Ca and Mg. 、 P element and the element Al A step to identify the concentration of each element in the ash component identification step, and based on the concentration of each element identified in the ash component identification step, the following formula ( 2 The system is characterized by comprising: an index value calculation step of calculating an index value I shown in ) and a chemical injection step of injecting a chemical into the sewage sludge based on the index value I. Index value I:M P-Al / (M P-Al +M Ca +M Mg )···(2) Here, in equation (2), M P-Al 、M Ca 、M Mg These are indices that depend on the concentrations of element P and element Al, respectively, an index that depends on the concentration of element Ca, and an index that depends on the concentration of element Mg.

[0009] According to the above configuration, an index value I indicating the ease of liquid phase formation is calculated based on the identified components of the incinerated ash, improving the accuracy of predicting blockages. Since chemicals are injected into the sewage sludge based on this index value I, it is possible to manage the incineration facility in a way that suppresses the occurrence of flue blockages more effectively than with conventional technology. As in this configuration, by defining the index that depends on the concentration of element P as an index that depends on the concentrations of both element P and element Al, it becomes easier to manage and further suppress flue blockage. In other words, according to thermodynamic equilibrium calculations, at the combustion temperature of the incinerator, P preferentially produces Al and phosphate (solid phase) over Ca and Mg, so the concentration of element P in the index value I can be corrected by the concentration of element Al, making it easier to suppress flue blockage more accurately.

[0010] In addition, the incineration treatment system according to the present invention includes an incineration treatment facility for incinerating sewage sludge, an ash component measuring device for measuring the components of the incineration ash obtained by incinerating the sewage sludge, a chemical injection device for injecting chemicals into the sewage sludge, and a control device for controlling the chemical injection device based on the measurement results obtained by the ash component measuring device. The control device includes an ash component specifying unit for specifying the concentrations of Ca element, Mg element 、 P element and the element Al in the incineration ash measured by the ash component measuring device, an index value calculating unit for calculating an index value I represented by the following formula ( 2 ), and a chemical injection control unit for causing the chemical injection device to inject the chemical based on the index value I. Index value I:M P-Al / (M P-Al +M Ca +M Mg )···(2) Here, in equation (2), M P-Al 、M Ca 、M Mg These are indices that depend on the concentrations of element P and element Al, respectively, an index that depends on the concentration of element Ca, and an index that depends on the concentration of element Mg.

[0011] According to the above configuration, since the index value I indicating the ease of liquid phase formation is calculated based on the specified components of the incineration ash, the prediction accuracy of blockage occurrence is improved. Since the chemical is injected into the sewage sludge based on this index value I, the occurrence of flue blockage can be suppressed more effectively than in the prior art. Furthermore, since the control for automatically injecting the chemical is performed based on the measurement results obtained by the ash component measuring device, the flue blockage of the incineration treatment facility can be promptly suppressed. As in this configuration, by defining the index that depends on the concentration of element P as an index that depends on the concentrations of both element P and element Al, it becomes easier to manage and further suppress flue blockage. In other words, according to thermodynamic equilibrium calculations, at the combustion temperature of the incinerator, P preferentially produces Al and phosphate (solid phase) over Ca and Mg, so the concentration of element P in the index value I can be corrected by the concentration of element Al, making it easier to suppress flue blockage more accurately.

[0012] Hereinafter, preferred embodiments of the present invention will be described. However, the scope of the present invention is not limited by the preferred embodiment examples described below.

[0015] In the management method for incineration equipment according to the present invention, it is preferable to calculate the index value I shown in formula (2) based on the following formula (3). Index value I: (am P -bm Al ) / (am P -bm Al +cm Ca +dm Mg )···(3) Here, in equation (3), m P , m Al , m Ca , m Mg is the molar concentration (mol / kg) of elements P, Al, Ca, and Mg in the incinerated ash, and a to d are predetermined coefficients.

[0016] According to this configuration, the index value I can be determined based on the molar concentration of each element in the incinerated ash.

[0017] The method for managing an incineration facility according to the present invention preferably includes, in the ash component identification step, further identifying the concentration of Fe element in the incinerated ash, and in the chemical injection step, injecting the chemical into the sewage sludge when the following formula (4) is satisfied. α×(index value I)+β>M Fe ...(4) Here, in equation (4), the coefficient α is a predetermined value within the range of 4.0 to 6.0, and the coefficient β is a predetermined value within the range of -3.0 to 0.0. Fe This is an index that depends on the concentration of the element Fe.

[0018] This configuration allows for the separation and comparison of the left-hand side of equation (4), which includes the index value I indicating the ease of liquid phase formation, with an index dependent on the concentration of Fe element, which is presumed to be involved in ash adhesion through mechanisms other than phosphate formation. This further improves the accuracy of flue blockage prediction. Furthermore, based on multiple samples for which flue blockage has been previously determined, coefficients α and β can be set for the index value I to form a dividing line between the presence and absence of flue blockage, and this can be compared with the index dependent on the concentration of Fe element shown on the right-hand side. This makes it easier to manage and further suppress flue blockage.

[0019] The method for managing an incineration facility according to the present invention is as follows: Fe However, it is preferable that it be represented by the following formula (5). M Fe =em Fe ...(5) Here, in equation (5), m Fe is the molar concentration (mol / kg) of element Fe in the incinerated ash, and e is a predetermined coefficient.

[0020] According to this configuration, based on the molar concentration of Fe element in the incinerated ash, M Fe It is possible to find this.

[0021] In the method for managing an incineration facility according to the present invention, it is preferable that the chemical agent contains a compound containing one or more metal elements selected from the group consisting of Fe, Ca, Mg, and Al.

[0022] According to this configuration, by adding a compound containing one or more metal elements selected from the group consisting of Ca, Mg, and Al to the sewage sludge, it is easier to adjust the index value I to be small with respect to the concentration of Fe, thereby suppressing the formation of the liquid phase. Furthermore, by adding a compound containing Fe, it is easier to adjust the concentration of Fe to be relatively high with respect to the index value I, thereby suppressing the formation of the liquid phase.

[0023] Further features and advantages of the present invention will become clearer through the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0024] [Figure 1] This figure shows an example of the treatment process at a sewage treatment plant. [Figure 2] This is a diagram illustrating an incineration system according to an embodiment. [Figure 3] This figure shows the output of thermodynamic equilibrium calculations based on the component composition of incinerated ash. [Figure 4]This figure shows the output of thermodynamic equilibrium calculations based on the component composition of incinerated ash. [Figure 5] This is a phase diagram of the P2O5+CaO system, taken from the database of thermodynamic equilibrium calculation software. [Figure 6] This is a phase diagram of the P2O5+MgO system, taken from the database within thermodynamic equilibrium calculation software. [Figure 7] This is a phase diagram of the P2O5+Al2O3 system, taken from the database of thermodynamic equilibrium calculation software. [Figure 8] This is a flowchart of the control process according to the embodiment. [Figure 9] This is a flowchart of the control process according to another embodiment. [Figure 10] This graph plots the molar concentration of iron against the index value I for the incinerated ash of each sample. [Figure 11] This is a diagram illustrating a conventional sewage sludge incineration facility. [Modes for carrying out the invention]

[0025] ≪First Embodiment≫ A first embodiment of the management method and incineration system for sewage sludge incineration equipment according to the present invention will be described with reference to the drawings. Below, an example of applying the management method for incineration equipment according to the present invention (hereinafter also simply referred to as the "management method") to the sewage sludge incineration system 1 will be described. The management method and incineration system 1 according to this embodiment manage the incineration equipment 10 to prevent ash deposits from adhering and causing flue blockage during sewage sludge incineration.

[0026] First, let's explain the sewage sludge that will be treated.

[0027] [Sewage sludge] Sewage sludge is the sludge generated during the purification treatment of sewage at a sewage treatment plant. A sewage treatment plant, for example, as shown in Figure 1, is equipped with treatment facilities using the activated sludge method. After large sand and debris are removed from the sewage in the grit tank, smaller contaminants are removed as the sewage flows through the primary sedimentation tank. Next, the sewage is introduced from the primary sedimentation tank to a reaction tank (biological reaction tank), where organic matter, nitrogen, and phosphorus are biologically treated, and then separated into microorganisms (activated sludge) and treated water in the final sedimentation tank. The sediment in the primary sedimentation tank and the sludge separated in the final sedimentation tank constitute sewage sludge. Typically, at a sewage treatment plant, it is concentrated in a thickening tank, and if necessary, treated in a digester to decompose organic matter and generate digester gas. After that, it is dewatered in a dewatering machine to become dewatered sludge, which is then transported to the incineration treatment facility 10. Known means of transport include piping, conveyors, or trucks.

[0028] [Configuration of the Incineration System] As shown in Figure 2, the incineration system 1 according to this embodiment comprises an incineration facility 10 for incinerating sewage sludge, an ash component measuring device 20 for measuring the components of the incinerated ash obtained by incinerating sewage sludge, a chemical injection device 30 for injecting chemicals into the sewage sludge, and a control device 40 for controlling the chemical injection device 30 based on the measurement results of the ash component measuring device 20.

[0029] (Incineration facility) The incineration facility 10 is a facility that incinerates sewage sludge to process it into gas and incinerated ash. In this embodiment, the incineration facility 10 incinerates sewage sludge (dewatered sludge) transported from a sewage treatment plant or the like as the material to be incinerated.

[0030] In detail, the incineration equipment 10 according to this embodiment includes a dewatered sludge storage section 12 that receives and stores dewatered sludge. The dewatered sludge stored in the dewatered sludge storage section 12 is discharged from the dewatered sludge storage section 12 using a pump or the like, depending on the incineration status in the incinerator 14, and transported to the supply unit 13. The configuration of the supply unit 13 is not particularly limited, but it may consist of a hopper that receives the dewatered sludge transported from the dewatered sludge storage section 12 and a screw conveyor (screw feeder), and may be configured to supply a fixed amount of dewatered sludge to the incinerator 14. The dewatered sludge may be dried using a dryer (not shown) before being transported to the supply unit 13. For example, a dryer may be provided between the dewatered sludge storage section 12 and the supply unit 13. As the dryer used for drying, known dryers such as hot air dryers and steam dryers can be used.

[0031] Next, the dewatered sludge is fed into the incinerator 14 by the feeder 13 and incinerated in the incinerator 14. Air is introduced into the incinerator 14 along with the material to be incinerated, and the material burns in an oxidizing atmosphere.

[0032] The incinerator 14 used in this embodiment is not particularly limited in its configuration, as long as it is an incinerator capable of incinerating sewage sludge. For example, a foamed fluidized bed furnace, a circulating fluidized bed furnace, a stoker furnace, etc., can be used. When a foamed fluidized bed furnace is used, the sewage sludge is mixed with fluidized sand (not shown) in the incinerator 14 and incinerated to produce sludge incineration ash.

[0033] Subsequently, the exhaust gas mixed with the incinerated ash produced by the incineration is treated. In this embodiment, the exhaust gas mixed with the incinerated ash discharged from the incinerator 14 is treated as waste heat by the heat exchanger 15, and fly ash is collected by the dust collector 16, as in the conventional method. The fly ash collected by the dust collector 16 is stored in the ash storage section 17. The exhaust gas discharged from the dust collector 16 is treated and purified by the flue gas treatment tower 18, and then released outside the system.

[0034] (Ash component measuring device) Before being sent to the ash storage unit 17, or while in the ash storage unit 17, a portion of the fly ash collected by the dust collector 16 is transported to the ash component measuring device 20. The ash component measuring device 20 according to this embodiment is a device capable of quantitatively analyzing the ratio of at least Ca, Mg, P, Al, and Fe elements in the incineration ash. The configuration of the ash component measuring device 20 is not limited as long as it is capable of measuring the component composition of each of the above elements in the incineration ash. In this embodiment, the ash component measuring device 20 is configured to include a sample loader 21 and an ash component analyzer 22. At the incineration temperature of the incinerator, 800°C to 1000°C, the amount of each of the elements Ca, Mg, P, Al, and Fe in the incineration ash of sewage sludge after incineration does not change significantly compared to the sewage sludge before incineration. That is, these elements contained in the sewage sludge are hardly emitted as gas (exhaust gas) and ultimately remain as solid (incineration ash).

[0035] The ash component analyzer 22 according to this embodiment may be any conventionally known analyzer, such as an ICP emission spectrometer (ICP-AES), an ICP mass spectrometer (ICP-MS), an atomic absorption spectrophotometer, an absorbance spectrophotometer, or other device for measuring liquid samples, or an X-ray fluorescence analyzer or other device for measuring solid samples. In the case of an absorbance spectrophotometer, the molybdenum blue method, the oxine extraction method, or the phenanthroline method may be applied.

[0036] If the ash component analyzer 22 is a device for measuring solid samples, the sample loader 21 prepares a sample for measurement by compressing and molding the incinerated ash into a shape (surface condition and density) suitable for measurement by the ash component analyzer 22, or by filling it into a measurement container, and then provides the sample for measurement to the sample rack of the ash component analyzer 22. On the other hand, if the ash component analyzer 22 is a device for measuring liquid samples, the sample loader 21 prepares a sample for measurement by performing pretreatment such as dissolution, decomposition, or melting on the incinerated ash according to the type of ash component analyzer, and then provides the sample for measurement to the sample rack of the ash component analyzer 22.

[0037] (Medication infusion device) The chemical injection device 30 is a device that injects chemicals into sewage sludge before it is incinerated in the incinerator 14. The chemical injection device 30 is preferably configured to inject the chemicals into the supply unit 13. This is because the supply unit 13 has a mixing function, making it easy to mix the injected chemicals with the sewage sludge and effectively suppressing flue blockage. In this embodiment, the chemical injection device 30 is installed so that the chemicals can be injected into the supply unit 13. The chemical injection device 30 may be, for example, an injection device using a general chemical injection pump.

[0038] In this embodiment, the chemical injected by the chemical injection device 30 includes a compound containing one or more metal elements selected from the group consisting of Fe, Ca, Mg, and Al. Examples of Mg-based chemicals include olivine ((Mg,Fe)2SiO4) and magnesium sulfate. Examples of Ca-based chemicals include calcium carbonate (CaCl3), slaked lime (Ca(OH)2), and quicklime (CaO). Examples of Mg and Ca combined chemicals include dolomite. Examples of Al-based chemicals include polyaluminum chloride (PAC). Examples of Fe-based chemicals include polyferric sulfate and ferric chloride (FeCl3). These chemicals may be supplied as solids or as aqueous solutions. The type of chemical injected may be appropriately selected from those readily available in the incineration facility 10, and may be used as a single type or a mixture of multiple types. The amount injected by the chemical injection device 30 is determined by the chemical injection control unit 43, which will be described later.

[0039] (Control device) The control device 40 controls the injection of chemicals into the sewage sludge, which is the material to be incinerated, to prevent ash deposits from adhering to the incineration equipment 10. The functions of each part of the control device 40 of the incineration system 1 according to this embodiment correspond to each step of the management method of this embodiment, and therefore will be described in relation to them. However, the control device 40 is not limited to the following embodiments and can be modified in various ways without departing from the gist of the invention.

[0040] The control device 40 includes an ash component identification unit 41 that identifies the concentration of each element in the incinerated ash measured by the ash component measuring device 20, an index value calculation unit 42 that calculates an index value I shown in the following formula (1) based on the concentration of each element identified by the ash component identification unit 41, and a chemical injection control unit 43 that causes the chemical injection device 30 to inject chemicals based on the index value I. The ash component identification unit 41 identifies the concentrations of at least Ca, Mg, and P elements. Index value I:M P / (M P +M Ca +M Mg )···(1) Here, in equation (1), M P M Ca M Mg These are indices that depend on the concentration of element P, the concentration of element Ca, and the concentration of element Mg, respectively.

[0041] Each functional unit of the control device 40 is constructed with a CPU as its core component, using hardware, software, or both, to perform processing related to the control of the chemical injection device 30, which is the target of control of the incineration treatment equipment 10. In addition to the ash component identification unit 41, the index value calculation unit 42, and the chemical injection control unit 43, the control device 40 also includes a storage unit 44.

[0042] Here, the process in which the ash component identification unit 41 identifies the concentrations of Ca, Mg, and P elements in the incinerated ash is called the ash component identification process, and the process in which the index value calculation unit 42 calculates the index value I shown in formula (1) above based on the concentrations of each element identified in the ash component identification process is called the index value calculation process. Furthermore, the process in which the chemical injection device 30 injects chemicals into the sewage sludge based on the control of the chemical injection control unit 43 based on the index value I is called the chemical injection process.

[0043] As described above, in the incineration system 1 according to this embodiment, the control device 40 controls the injection of chemicals into the sewage sludge, which is the material to be incinerated, based on the component measurement results of the ash component measuring device 20. This controls the component composition (elemental composition) of the sewage sludge so that ash adhesion inside the incineration equipment 10 is less likely to occur. Through this control, the incineration equipment 10 is managed so that it can continue to operate while suppressing flue blockage.

[0044] As mentioned above, flue blockage due to ash buildup in sewage sludge incinerators is generally known to occur when low-melting-point components in the incinerated ash melt and form a liquid phase during the incineration process. It is also generally known that the likelihood of ash buildup differs depending on the component composition of the incinerated ash. Conventionally, various indicators for suppressing flue blockage by incinerated ash have been studied, as described in Patent Documents 1 and 2, and chemical agents have been added based on these indicators.

[0045] However, since flue blockage still occurs even when the above-mentioned agents are added according to various index values, including the blockage suppression index X of Patent Document 1, the inventors performed elemental analysis on incinerated ash when flue blockage occurred (blockage sample) and incinerated ash when flue blockage did not occur (non-blockage sample) in an incineration facility in actual operation. The results of each analysis were input into thermodynamic equilibrium calculation software (FactSage®) to perform thermodynamic equilibrium calculations. The temperature condition for the thermodynamic equilibrium calculations was set to 900°C, close to the incineration temperature in the incinerator 14, and the calculations were performed on the component composition of incinerated ash sampled at two incineration facilities (facility P and facility Q). The elemental component composition (mass%) is shown in Table 1.

[0046] [Table 1]

[0047] Figure 3 shows the output of thermodynamic equilibrium calculations at a temperature of 900°C for the component compositions of sample P1, in which flue blockage occurred, and sample P2, in which flue blockage did not occur, in facility P. As shown in Figure 3, in facility P, the liquid phase ratio of sample P1, in which flue blockage occurred, was 30%, and the liquid phase ratio of sample P2, in which flue blockage did not occur, was 24%.

[0048] Furthermore, Figure 4 shows the output results of thermodynamic equilibrium calculations at 900°C for each component composition of sample Q1, in which flue blockage occurred, and sample Q2, in which flue blockage did not occur, in facility Q. As shown in Figure 4, the liquid phase ratio of sample Q1, in which flue blockage occurred, was 50%, and the liquid phase ratio of sample Q2, in which flue blockage did not occur, was 33% (Figure 4).

[0049] In both equipment P and Q, it was confirmed that the liquid phase proportion was higher in the samples with blockages than in the samples without blockages at the combustion temperature of 900°C. This suggests that the liquid phase proportion is related to the generation of ash deposits in incineration equipment. Furthermore, from the output results in Figures 3 and 4, it was estimated that the components forming the liquid phase are mainly P2O5, CaO, MgO, and SiO2.

[0050] Furthermore, the results of the thermodynamic equilibrium calculations in Figures 3 and 4 suggest that at 900°C, each metal element in the incinerated ash does not uniformly produce a specific phosphoric acid compound (phosphate). While Mg, Ca, and Si elements form a liquid phase together with P, as shown in the comparison between samples P1 and P2, it is estimated that Ca generates phosphate along with the liquid phase at high concentrations, while Al does not form a liquid phase, preferentially producing solid-phase phosphate, and potentially solid-phase silicate. In addition, since Si is mostly present in the solid phase in the form of SiO2 and KAlSi3O8, and its proportion in the liquid phase is relatively small, it is estimated that its relationship with P, which is involved in liquid phase formation, is lower than that of Ca, Mg, and Al. In other words, it is estimated that each element in the incinerated ash exhibits different behaviors depending on the type and composition of the element at the incineration temperature of 900°C.

[0051] Therefore, the inventors conducted further detailed studies and investigated the melting behavior of systems in which the composition ratio of Ca to P (phosphorus) was changed, systems in which the composition ratio of Mg to P (phosphorus) was changed, and systems in which the composition ratio of Al to P (phosphorus) was changed, based on the phase diagram database in thermodynamic equilibrium calculation software (FactSage®).

[0052] Figures 5 to 7 show the phase diagrams of each metal element (Ca, Mg, Al) for P, taken from the phase diagram database within the thermodynamic equilibrium calculation software (FactSage®). In this invention, since the subject is incinerator ash produced under an oxidizing atmosphere, the oxide phase diagrams of the above elements were referred to.

[0053] As shown in Figure 5, it is estimated that in the incineration temperature range of the incinerator (800-1000°C), Ca produces phosphorus (P) and a liquid phase (Slag(l)), or a mixture of solid and liquid phases, in a concentration range where the molar ratio of P2O5 to (P2O5 + CaO) [P2O5 / (P2O5 + CaO)] is approximately 0.5 or higher. Similarly, as shown in Figure 6, it is estimated that Mg produces phosphorus (P) and a liquid phase (Slag(l)), or a mixture of solid and liquid phases, in the incineration temperature range of the incinerator (800-1000°C), in a concentration range where the molar ratio of P2O5 to (P2O5 + MgO) [P2O5 / (P2O5 + MgO)] is approximately 0.5 or higher. Based on the phase diagrams shown in Figures 5 and 6, the inventors estimated that the elements Ca and Mg exhibit similar properties to the element P in the incineration temperature range of an incinerator (800-1000°C).

[0054] On the other hand, as shown in Figure 7, it is estimated that in the incineration temperature range of an incinerator (800-1000°C), Al produces solid (solid phase) AlP3O9, AlPO4, and Al2O3 in a wide concentration range where the molar ratio of P2O5 to (P2O5 + Al2O3) [P2O5 / (P2O5 + Al2O3)] is approximately 0.75 or less. The inventors of the present invention inferred from the phase diagram shown in Figure 7 that Al exhibits different properties with respect to P compared to Ca and Mg, and that it reacts with P preferentially to Ca and Mg to form a solid phase.

[0055] Although the element Fe is generally known as a component that suppresses ash adhesion, the thermodynamic equilibrium calculations mentioned above (Figures 3 and 4) also show that the solid phase oxides Fe2O3, and Fe2P2O8 and Fe6P2O 14 It was estimated that these elements are preferentially generated. Furthermore, based on past experimental data on the principle of suppressing flue blockage in sewage sludge, it is highly likely that the element Fe generates oxides such as Fe2O3 at incineration temperatures, and a mechanism for suppressing ash deposits through the physical interaction between Fe2O3 and P2O5 has also been proposed (for example, Kenyo Ito, "Mechanism of increased high-temperature adhesion of fly ash from sewage sludge incineration and its control," Doctoral dissertation, Tokyo University of Agriculture and Technology, 115-(2022), etc.). Thus, it is estimated that the element Fe does not participate in liquid phase formation, and furthermore, the generation of Fe2O3 takes precedence over phosphate formation with the element P. Therefore, the inventors estimated that the element Fe is involved in ash adhesion through a mechanism different from that of Ca, Mg, and Al.

[0056] Based on the above findings, the inventors conceived of defining an index value I indicating the ease of liquid phase formation using the above formula (1). In the above formula (1), M P M is an index that depends on the concentration of element P. Ca M is an index that depends on the concentration of element Ca. Mg is an index that depends on the concentration of the element Mg. In equation (1) above, the denominator (M P +M Ca +M Mg ) represents the sum of indices (P, Ca, and Mg) that depend on the concentration of specific elements involved in liquid phase formation, and the molecule (MP The index I represents an index that depends on the concentration of the phosphorus (P) element present. In other words, the index value I indicates the proportion of the phosphorus element among the elements involved in liquid phase formation. The larger the index value I, the larger the proportion of the phosphorus element and the smaller the proportion of (Ca + Mg) elements. Since Ca and Mg elements are more likely to form a liquid phase with the phosphorus element, it can be estimated that flue blockage is more likely to occur. On the other hand, the smaller the index value I, the smaller the proportion of the phosphorus element and the larger the proportion of (Ca + Mg) elements. Since Ca and Mg elements are more likely to form a solid phase with the phosphorus element, it can be estimated that flue blockage is less likely to occur.

[0057] Here, M is an index that depends on the concentration of element P. P This is not limited to the concentration of element P in the incinerated ash, but may be a numerical value that relatively indicates the magnitude of the concentration of element P in the incinerated ash. Similarly, M, an index that depends on the concentration of element Ca, may also be used. Ca This may be a numerical value that relatively indicates the magnitude of the concentration of Ca element in the incinerated ash, and is an index that depends on the concentration of Mg element. Mg This can be a numerical value that relatively indicates the magnitude of the Mg element concentration in the incinerated ash. In that sense, the units used to indicate the concentration of each element are not limited to a specific unit, and various units can be used.

[0058] In this embodiment, the ash component identification step (ash component identification unit 41) further includes identifying the concentration of Al element in the incinerated ash, and the exponent M in formula (1) p However, the exponent M depends on the concentrations of element P and element Al. P-Al The index value I is assumed to be given by the following formula (2). Index value I:M P-Al / (M P-Al +M Ca +M Mg )···(2) Here, in equation (2), M P-Al M Ca M Mg These are indices that depend on the concentrations of element P and element Al, respectively, an index that depends on the concentration of element Ca, and an index that depends on the concentration of element Mg.

[0059] As shown in Figure 7, it is estimated that Al (Al) generates P (P) and phosphate (solid phase) over a wide concentration range around the combustion temperature of the incinerator, which is 800°C to 1000°C. Also, in Figures 3 and 4, it is estimated that Al generates P and phosphate preferentially to Ca (Ca) and Mg (Mg) elements. From these observations, it can be estimated that Al is a component that consumes P, which is involved in liquid phase formation. Therefore, the "index dependent on the concentration of P" is defined as the "index dependent on the concentration of P and the concentration of Al" to correct the concentration of P involved in liquid phase formation. This configuration is considered to make it easier to manage and further suppress flue blockage.

[0060] In this embodiment, the index value I shown in formula (2) is calculated based on the following formula (3). Index value I: (am P -bm Al ) / (am P -bm Al +cm Ca +dm Mg )···(3) Here, in equation (3), m P , m Al , m Ca , m Mg is the molar concentration (mol / kg) of elements P, Al, Ca, and Mg in the incinerated ash, and a to d are predetermined coefficients. With this configuration, the index value I can be easily determined because it is based on the molar concentration of elements P, Al, Ca, and Mg in the incinerated ash.

[0061] In equation (3), coefficients a and b are preferably 1, coefficient c is preferably a predetermined value within the range of 0.5 to 1.5, and coefficient d is preferably a predetermined value within the range of 0.5 to 1.0. P-Al , am P -bm Al When the value becomes negative, it means that the P element is consumed by the Al element, and that the P element involved in liquid phase formation is unlikely to exist, so the index value I can be set to 0 (zero).

[0062] As defined above, if the index value I is above a predetermined threshold, there is a high probability of liquid phase formation and a tendency for flue blockage to occur. Therefore, when the chemical injection control unit 43 determines that the index value I is above a predetermined threshold, the chemical injection control unit 43 controls the chemical injection device 30 and injects the chemical into the sewage sludge. The predetermined threshold is not limited to this, but for example, if the index value I is 0.5 or higher, ash deposits will be generated and the probability of flue blockage will increase.

[0063] Next, with reference to the flowchart in Figure 8, an example of a control process according to the first embodiment performed by the control device 40 of the incineration system 1 will be described. In the control process according to the first embodiment, a chemical injection process is performed based on the index value I.

[0064] First, in the control device 40, the ash component identification unit 41 acquires and identifies the concentrations of Ca, Mg, Al, and P elements in the fly ash measured by the ash component measuring device (step #10).

[0065] Next, the index value calculation unit 42 calculates the index value I based on the above formula (3) using the concentrations of each element identified by the ash component identification unit 41 (step #11). Formula (3) for the index value I is stored in the storage unit 44.

[0066] Next, the drug infusion control unit 43 determines whether the index value I is equal to or greater than a predetermined threshold (step #12).

[0067] When the index value I is greater than or equal to a predetermined threshold (i.e., when the answer is Yes in step #12), there is a high risk of flue blockage in the incineration equipment 10, so the chemical injection control unit 43 executes a control to inject chemical into the chemical injection device 30 (step #13). At this time, for example, the amount of chemical to be injected may be determined by the difference between the calculated index value I and the predetermined threshold. For example, the memory unit 44 may store a linear equation for each type of chemical that calculates the amount of chemical to be injected from the value of (calculated index value I - predetermined threshold), and the amount of chemical to be injected may be determined by this linear equation. The reason for using a linear equation here is that it was considered as a model that each parameter of the index value I and the required amount of chemical are in a linear relationship.

[0068] On the other hand, when the index value I is less than a predetermined threshold (i.e., when it is No in step #12), the risk of flue blockage in the incineration equipment 10 is low, so the chemical injection control unit 43 does not execute control for the chemical injection device 30 to inject chemicals.

[0069] As described above, by repeatedly performing the control including #10 to #13 in Figure 8, the incineration equipment 10 is properly managed to prevent flue blockage from occurring inside it. As a result, troubles with the incineration equipment 10, such as emergency shutdowns, can be prevented and suppressed.

[0070] In the aforementioned prior art (for example, Patent Document 1), the blockage suppression index is defined based on the assumption that, at the incineration temperature inside the incinerator, a reaction occurs uniformly in which element P and each metal element (Fe, Al, Ca, Mg) combine in predetermined proportions to produce phosphate. That is, in the blockage suppression index X in Patent Document 1, it is assumed that Fe and P combine in a 1:1 molar ratio to produce Fe(PO4), Al and P combine in a 1:1 molar ratio to produce Al(PO4), Ca and P combine in a 3:2 molar ratio to produce Ca3(PO4)2, and Mg and P combine in a 3:2 molar ratio to produce Mg3(PO4)2. However, the index value I according to this embodiment focuses on the state at the incineration temperature and the concentration of each element inside the incinerator, and defines the ease of liquid phase formation using a different approach than the prior art. In other words, in the index value I of this embodiment, Ca and Mg are positioned as elements involved in liquid phase formation with P, and Al is positioned as a component that consumes P, which is involved in liquid phase generation. The management method of the incineration system 1 and incineration equipment 10 according to this embodiment controls the presence or absence and amount of chemical injection based on this index value I, making it easier to suppress liquid phase formation than in the conventional method. As a result, it is easier to suppress the generation of ash deposits on each piece of equipment from the incinerator 14 to the dust collector 16 and the piping connecting them, thereby suppressing flue blockage, reducing the number of maintenance operations required to remove accumulated incinerated ash, and preventing the incineration equipment from shutting down due to flue blockage.

[0071] The management method and incineration system 1 according to this embodiment are particularly useful in that they can prevent and suppress flue blockage because they have a high accuracy in predicting sewage sludge that is likely to cause blockage. If the prediction of sewage sludge that is likely to cause blockage is incorrect, the injection of chemicals will not be carried out, and flue blockage will occur with a high probability. According to the management method and incineration system 1 according to this embodiment, the incineration equipment (actual machine) can be managed so that flue blockage does not occur.

[0072] ≪Second Embodiment≫ Next, a second embodiment of the management method for the sewage sludge incineration facility 10 and the incineration system 1 according to the present invention will be described. Note that configurations not specifically mentioned are the same as in the first embodiment, and therefore detailed explanations will be omitted.

[0073] In the second embodiment, the ash component identification step (ash component identification unit 41) further includes identifying the concentration of Fe element in the incinerated ash. In the chemical injection step according to the second embodiment, when the control device 40 determines that the following formula (4) is satisfied, the chemical injection control unit 43 controls the chemical injection device 30 and injects the chemical into the sewage sludge. α×(index value I)+β>M Fe ...(4) In other words, equation (4) is an equation that, when satisfied, is likely to cause ash deposits to form, and represents conditions that are prone to blockage (also called blockage conditions). Here, in equation (4), the coefficient α is a predetermined value within the range of 4.0 to 6.0, and the coefficient β is a predetermined value within the range of -3.0 to 0.0. M Fe This is an index that depends on the concentration of the element Fe.

[0074] The coefficient α in equation (4) is preferably between 4.5 and 5.5. The coefficient β is preferably a predetermined value within the range of -2.0 to -1.5, and more preferably between -1.8 and -1.6. As shown in the examples described later, for example, setting the coefficient α to 5.1 and the coefficient β to -1.7 tends to particularly improve the accuracy of flue blockage prediction.

[0075] In this embodiment, M Fe This is assumed to be represented by the following formula (5). M Fe =em Fe ...(5) Here, in equation (5), m Fe is the molar concentration (mol / kg) of the element Fe in the incinerated ash, and e is a predetermined coefficient. According to the above configuration, based on the molar concentration of the element Fe in the incinerated ash, M FeThis makes it easier to determine. The predetermined coefficient in equation (5) may be in the range of, for example, 0.5 to 1.5, and in this embodiment it is set to 1. With this configuration, since it is based on the molar concentration of Fe element in the incinerated ash, M Fe It is easy to find.

[0076] Next, with reference to the flowchart in Figure 9, an example of a control process according to the second embodiment performed by the control device 40 of the incineration system 1 will be described. In the control process according to the second embodiment, the chemical injection process is performed based on the above equation (4).

[0077] First, in the control device 40, the ash component identification unit 41 acquires and identifies the concentrations of Ca, Mg, Al, Fe, and P elements in the fly ash measured by the ash component measuring device 20 (step #20). In the control step according to the second embodiment, in addition to the elements acquired and identified in the control step according to the first embodiment, the concentration of Fe is acquired and identified.

[0078] Next, the index value calculation unit 42 calculates the index value I shown in formula (1) above, based on the concentrations of Ca, Mg, Al, and P elements identified by the ash component identification unit 41 (step #21). Formula (3) for the index value I is stored in the storage unit 44.

[0079] Next, the drug infusion control unit 43 calculates the left side of equation (4) which includes the index value I, and compares this with the Fe concentration which is the right side of equation (4) to determine the relative magnitudes of the left and right sides (step #22).

[0080] Left side [α × (index value I) + β] > Right side (M Fe When this is true and equation (4) above is satisfied (i.e., when the answer is Yes in step #22), there is a high risk of flue blockage in the incineration equipment 10, so the chemical injection control unit 43 executes control for the chemical injection device 30 to inject chemical (step #23). At this time, the amount of chemical to be injected may be determined by, for example, the following procedure. [1] A database of sewage sludge samples (preferably 50 or more samples) with known elemental concentrations (P, Al, Ca, Mg, Fe, etc.) and blockage status is prepared in advance based on past actual machine data, literature data, etc. For a large number of known sewage sludge samples in the database, the index values ​​I and M Fe Determine each of these, and the index values ​​I and M Fe Numerous relationships are plotted to derive a linear equation that indicates the boundary between obstructed and unobstructed samples. A linear equation is used because, as in equation (4), the model assumes that the parameter dependent on the concentration of each element and the required amount of drug are in a linear relationship. The process of deriving the linear equation corresponds to the process of determining the coefficients α and β in equation (4). The coefficients α and β can be determined, for example, by trial and error to determine the slope and intercept of the linear equation so that the samples with and without obstruction are divided as well as possible, or they can be determined using a pattern recognition algorithm such as a support vector machine. As illustrated in Figure 10 of the example described later, the index value I is on the X axis, and M Fe If we plot the (concentration of element Fe) on the Y-axis, we can set up a linear equation as a dividing line between the region with and without occlusion, such that the upper part of the line segment represents the region without occlusion, and the lower part represents the region with occlusion. [2] As explained using Figure 10, if the plot of incinerated ash according to this embodiment falls within the area of ​​obstruction below the dividing line, the risk of flue obstruction is high. Therefore, the plot is moved upward or to the left, and the chemical is injected so that the plot is on or above the dividing line. For example, when injecting a compound containing Fe as the chemical, the amount of chemical to be injected should be determined so that the index value I moves to the area above the plot and reaches the dividing line or above the dividing line. Also, when injecting a compound containing one or more of Al, Mg, and Ca as the chemical, the amount of chemical to be injected should be set as the target value so that the plot moves to the left and reaches the dividing line or above the dividing line. In detail, since the target value can be set using the dividing line described above, the amount of chemical to be injected can be determined using the goal seek function of spreadsheet software (for example, Microsoft Excel®).

[0081] On the other hand, when the left side is less than or equal to the right side and equation (4) above is not satisfied (i.e., when the answer is No in step #22), the risk of flue blockage in the incineration equipment 10 is low, so the chemical injection control unit 43 does not execute the control for the chemical injection device 30 to inject chemicals.

[0082] As described above, by repeating the control including #20 to #23 in Figure 9, the incineration facility 10 is properly managed to prevent flue blockage from occurring inside it.

[0083] According to the second embodiment, the left side of equation (4), which includes an index value I indicating the ease of liquid phase formation, [α × (index value I) + β] is expressed as an index (M) that depends on the concentration of Fe element involved in flue blockage by another mechanism. Fe Since it is separated and compared with the first embodiment, the accuracy of flue blockage prediction can be further improved. As a result, the reliability of flue blockage countermeasures is improved. Furthermore, according to the second embodiment, coefficients α and β can be set for the index value I so as to be a dividing line between the presence or absence of flue blockage, based on the elemental concentrations of known samples whose presence or absence of flue blockage has been confirmed in the past. This makes it possible to set blockage conditions in association with data on the actual occurrence of flue blockage, and to further improve prediction accuracy.

[0084] [Other embodiments] Other embodiments of the incineration equipment management method and incineration system according to the present invention will be described below. Note that the configurations disclosed in each of the following embodiments can be applied in combination with configurations disclosed in other embodiments, provided that no inconsistencies arise.

[0085] In the above embodiment, a configuration was described as in which a chemical injection device 30 is installed so that chemicals can be injected into the supply unit 13, and chemicals are injected into the supply unit 13. However, the location of the chemical injection device 30 and the location where the chemical injection device 30 injects the chemicals are not particularly limited, as long as the chemicals can be injected into the sewage sludge before incineration. For example, the chemical injection device 30 may be installed to inject the chemicals into the dewatered sludge storage unit 12 in Figure 2, or if the means of transporting sludge to the supply unit 13 is equipment such as pipes or pumps, the chemical injection device 30 may be installed to inject the chemicals into such pipes or equipment. In addition, chemicals may be injected into dewatered sludge that has been dewatered by a dewatering machine at a sewage treatment plant, or the chemicals may be transported from a sewage treatment plant and injected at another location.

[0086] In the above embodiment, the management method for the incineration equipment 10 was described as an example of a configuration applied to an incineration system 1 that can automatically sample incinerated ash, measure the ash component concentration, and automatically manage ash adhesion. However, the management method for the incineration equipment 10 in the present invention is not limited to a configuration that automatically measures and manages ash adhesion to the incineration equipment 10. For example, sampling of incinerated ash from sewage sludge may be done in a batch manner rather than a continuous manner, or sampling of incinerated ash may be done manually.

[0087] In the above embodiment, the ash component identification device (ash component identification process) was described as an example in which fly ash sampled between the dust collector 16 and the ash storage unit 17 was used as incinerated ash. However, the incinerated ash used to identify each element in the ash component identification device (ash component identification process) is not limited to that sampled between the dust collector 16 and the ash storage unit 17, but may be sampled in the piping and equipment after the incinerator 14. For example, the incinerated ash may be collected in the ash storage unit 17. Furthermore, the incinerated ash used to identify each element in the ash component identification device (ash component identification process) is not limited to that obtained by incinerating sewage sludge in the incinerator 14, but may be dewatered sludge sampled before being fed into the incinerator 14 and ashed in another device. In this case, the dewatered sludge is preferably sampled at any point along the path from the dewatering machine at the sewage treatment plant to the incinerator 14, and is even more preferably sampled in the piping before or after the supply unit 13.

[0088] In the above embodiment, a configuration using an ash component measuring device 20 capable of automatic measurement of ash components was described as an example. However, the ash component measuring device 20 applied to the control method of the present invention does not have to be an ash component measuring device 20 capable of automatic measurement, and the measurement of ash components may be performed by manual analysis. In this case, the measurement of ash components may be performed in a batch manner using the various measuring devices and methods described above, or by manual analysis using titration. In the case of volumetric analysis by titration, methods using EDTA reagent for Ca and Mg, EDTA-zinc reagent for Al, and K3Cr2O7 (potassium dichromate) reagent for Fe may be employed.

[0089] Elemental concentration measurements in incinerated ash may be performed not only by the method described above in accordance with JIS R5204 (published in 2019) "Fluorescent X-ray Analysis of Cement," but also by the methods described in JIS M8815 (published in 1976) "Analytical Methods for Coal Ash and Coke Ash" and JIS R5202 (published in 2024) "Chemical Analysis Methods for Cement."

[0090] In the above embodiment, a configuration in which equation (3) is applied as the formula for calculating the index value I was described as an example. However, in the management method and incineration system of the present invention, the index value I may be calculated by applying equations (1) and (2), and other units of concentration other than molar concentration (mol / kg) may be used.

[0091] In the above embodiment, a configuration in which the control device 40 performs a series of steps for injecting chemicals into sewage sludge was described as an example. However, each step in the management method of the present invention (ash component identification step, index value calculation step, and chemical injection step) is not limited to being performed by the control device 40, and all of these steps may be performed by a person, or at least some of the steps may be performed by a person. For example, if all of the ash component identification step, index value calculation step, and chemical injection step are performed by a person, the person may identify the concentration of each element in the incinerated ash measured by the ash component measuring device 20, etc., on a spreadsheet (ash component identification step), calculate the index value I on the spreadsheet based on the above formulas (1) to (5), etc. (index value calculation step), and based on the index value I, the operator of the incineration treatment equipment may manually set the target value of the chemical injection amount of the chemical injection device and inject the chemical (chemical injection step). The chemical injection process can be any process that involves injecting a chemical into the sewage sludge based on an indicator value I, and is not limited to changing the amount of chemical injected based on the indicator value I. The frequency of chemical injection, the dilution ratio of the chemical, etc., may also be changed based on the indicator value I.

[0092] In the above embodiment, a configuration in which equations (3) and (5) are applied to equation (4) was described as an example. However, the index value I used in equation (4) in the management method and incineration system of the present invention may be calculated by applying equations (1) and (2), and equation (5) is not necessarily applied in equation (4). Other units of concentration other than molar concentration (mol / kg) may also be used.

[0093] With regard to other configurations, the embodiments disclosed herein are illustrative in all respects, and it should be understood that the scope of the present invention is not limited thereto. Those skilled in the art will modify them as appropriate without departing from the spirit of the invention. Accordingly, other embodiments modified without departing from the spirit of the invention are naturally included within the scope of the present invention. [Examples]

[0094] The present invention will be further described below with reference to examples. However, the following examples are not intended to limit the present invention.

[0095] <Explanation of the sample> (a) Samples derived from sewage sludge We prepared 50 different samples derived from actual sewage sludge (samples taken from operational incineration facilities, with varying sampling locations, timings, and morphological conditions; all samples for which elemental analysis results and blockage status were known). (b) Previous literature data To verify the application of this invention, we prepared 18 existing literature data sets that describe elemental analysis results and the presence / absence of blockage. For convenience, both (a) and (b) will be referred to as "samples". Of these, samples 1-25 are "obstructed" samples, with samples 1-20, 24, and 25 corresponding to (a) and samples 21-23 corresponding to (b). The remaining 43 samples are "not obstructed" samples, of which 28 correspond to (a) and 15 correspond to (b).

[0096] The previous literature from which data for each sample in (b) was cited is the following publications issued by the Japan Sewage Works Association. (Samples 21, 22, and 10 samples without obstruction) Kurozumi, Mitsuhiro et al., Method for evaluating the risk of blockage in sewage sludge incinerators and methods for preventing blockage, Journal of the Japan Sewage Works Association, Vol. 53, 2016 / 9, No. 647, pp. 88-97. (Sample 23, 2 samples without obstruction) Hattori, Satoshi et al., Incinerator clogging due to increased phosphorus content in sludge following changes in water treatment operation and a case study of countermeasures, Proceedings of the 61st Japan Sewerage Research Conference, 2024, pp. 919-921. (One sample without obstruction) Kishimoto, Osamu et al., Structure of sintered material generated during incineration of sewage sludge and a method for suppressing flue blockage using artificial intelligence, Proceedings of the 58th Japan Sewerage Research Conference, 2021, pp. 866-868. (Two samples without obstruction) Tada, Takumi. Sintering prevention effect of water treatment soil in fluidized bed incineration facilities. Proceedings of the 59th Japan Sewerage Research Conference, 2022, pp. 886-888.

[0097] Of the samples in (a) above, the samples in the form of incinerated ash were taken directly from the incineration facility and used for elemental measurement. The samples in the form of dewatered sludge were dried beforehand, then completely combusted in a furnace under an oxidizing atmosphere to produce incinerated ash, which was then used for elemental measurement. Carbonized sludge and dried sludge were also completely combusted in a furnace under an oxidizing atmosphere to produce incinerated ash, which was then used for elemental measurement.

[0098] The concentrations (content) of CaO, MgO, P2O5, Al2O3, Fe2O3, SiO2, TiO2, Na2O, and K2O in each incinerated ash of the samples in (a) above were measured using a method in accordance with JIS M 8815 (published in 1976) "Analytical Methods for Coal Ash and Coke Ash". The samples in (b) above include those measured using a method in accordance with JIS R5202 (published in 2024) "Chemical Analysis Methods for Cement" in addition to the method in accordance with JIS M8815 (published in 1976) "Analytical Methods for Coal Ash and Coke Ash". Specifically, for samples 1 to 25, the component composition (mass %) in each incinerated ash was measured using one of the following methods: ICP emission spectrophotometer, atomic absorption spectrophotometer, X-ray fluorescence analyzer, or gravimetric method (especially for the Si element).

[0099] <Satisfaction of occlusion conditions based on index value I and equation (4)> For Samples 1 to 25 with blockages, the component compositions (mass %) in each incineration ash were converted to molar concentrations (mol / kg). The mass per mole of each elemental component used the following values: CaO (56.1 g / mol), MgO (40.3 g / mol), P2O5 (142.0 g / mol), Al2O3 (102.0 g / mol), Fe2O3 (159.6 g / mol), SiO2 (60.1 g / mol), TiO2 (79.9 g / mol), Na2O (62.0 g / mol), K2O (94.2 g / mol)

[0100] From the molar concentrations (mol / kg) of each element, the index value I was calculated using the following formula (6). Index value I = (m P - m Al ) / (m P - m Al + m Ca + m Mg ) ··· (6) In formula (6), m P , m Al , m Ca , m Mg are the molar concentrations (mol / kg) of P element, Al element, Ca element, and Mg element in the incineration ash. That is, in the examples, all the coefficients a to d in formula (3) were set to 1.

[0101] From the obtained index value I, the value of [α × (index value I) + β], which is the left side of the above formula (4), was determined. In this example, based on the database of past known data with / without blockages, α was set to 5.1 and β was set to -1.7.

[0102] Next, the value of [α × (index value I) + β], which is the left side of the above formula (4), was compared with the molar concentration (mol / kg) of Fe element. That is, in the examples, the coefficient e in formula (5) was set to 1.

[0103] For samples 1 to 25, Tables 2 to 4 show the component composition (mass%), the index value I calculated from each component composition, [α × (index value I) + β], and the molar concentration of Fe element (mol / kg). For index value I, a value of 0.5 or higher was used as the occlusion condition, and the satisfaction of "index value I ≥ 0.5" is shown in Tables 2 to 4. The satisfaction of equation (4), which represents the occlusion condition, is also shown in Tables 2 to 4.

[0104] [Table 2]

[0105] [Table 3]

[0106] [Table 4]

[0107] Furthermore, for comparison, the blockage suppression index X shown in Patent Document 1 and index A shown in Patent Document 2 were calculated from the above elemental composition and are shown in Tables 2 to 4. The criteria for each index and their respective evaluation criteria are as follows.

[0108] <Occclusion suppression index X> The following formula (7) was used to calculate the blockage suppression index X. Fe2O3 is the mass percentage of Fe2O3 in the incinerated ash, Al2O3 is the mass percentage of Al2O3 in the incinerated ash, CaO is the mass percentage of CaO in the incinerated ash, MgO is the mass percentage of MgO in the incinerated ash, and P2O5 is the mass percentage of P2O5 in the incinerated ash. M(i) is the molecular weight [g / mol] of the compound or element i. In the blockage suppression index X described in Patent Document 1, a high risk of blockage was determined when the "blockage suppression index X ≤ 0.9".

number

[0109] <Indicator A> Equation (8) was used as the formula for calculating index A. In the case of index A related to Patent Document 2, a high risk of obstruction was determined when "index A > 0.3". Index A: ([Fe2O3]+[CaO]+[Na2O]+[K2O]+[MgO]) / ([SiO2]+[Al2O3]+[TiO2])×[P2O5] / 100...(8) In formula (8), each element represents the mass percentage (mass%) of each component relative to the total amount of all components. In Tables 2-4, samples for which one or more of the elements SiO2, TiO2, Na2O, and K2O were not analyzed are marked as "Analysis not performed," and no determination of index A was made.

[0110] Based on the results in Tables 2-4, Table 5 shows the accuracy rate of the occlusion prediction results based on the type of indicator for samples 1-25 with occlusion.

[0111] [Table 5]

[0112] In occlusion prediction based on occlusion suppression index X (Patent Document 1), the number of correct answers for samples with occlusion was 18 out of 25 samples, resulting in an accuracy rate of 72%. In occlusion prediction based on index A (Patent Document 2), the number of correct answers for samples with occlusion was 1 out of 12 samples, resulting in an accuracy rate of 8%.

[0113] In contrast, the blockage prediction based on index value I according to the present invention resulted in 23 out of 25 samples correctly identifying samples with blockage, with an accuracy rate of 92%. The blockage prediction based on formula (4) according to the present invention resulted in 24 out of 25 samples correctly identifying samples with blockage, with an accuracy rate of 96%. From these results, it was confirmed that index value I and formula (4) of the present invention are excellent at predicting samples that are highly likely to experience flue blockage.

[0114] <Setting the dividing line for blockage / absence> Next, for the 43 samples without obstruction, the index value I and the molar concentration of Fe element (mol / kg) were calculated in the same way as for samples 1 to 25. Figure 10 shows the results of plotting the molar concentration of Fe element (mol / kg) against the index value I for each of the 68 samples, including the additional samples without obstruction. In Figure 10, the 25 samples with obstruction (samples 1 to 25) are plotted with "×", and the 43 samples without obstruction are plotted with "●". Note that in Figure 10, m P -m Al For values ​​that were negative, the molar concentration of Fe element (mol / kg) was plotted on the Y-axis, with the index value I being considered zero.

[0115] In Figure 10, the line segment was set by trial and error so that the sample with blockage was located on the lower side and the sample without blockage was located on the upper side of the dividing line. The set gradient (i.e., α in equation (4)) was 5.1 and the intercept (i.e., β in equation (4)) was -1.7. The incineration equipment management method and incineration treatment system according to the present invention is achieved by injecting a chemical agent into the sewage sludge plotted in the region below the dividing line in Figure 10, so that the plot moves upward or to the left and the plot is on or above the dividing line. For example, when injecting a compound containing the element Fe as the chemical agent, the amount of chemical agent to be injected should be determined so that the index value I moves to the region above the plot and reaches the dividing line or above the dividing line. Also, when injecting a compound containing one or more of the elements Al, Mg, and Ca as the chemical agent, the amount of chemical agent to be injected should be set as the target value so that the plot moves to the left and reaches the dividing line or above the dividing line. In detail, since target values ​​can be set using the division lines described above, the amount of drug to be injected can be determined using the goal-seek function of spreadsheet software (for example, Microsoft Excel®). These drugs may be used individually or in combination of multiple types. [Industrial applicability]

[0116] This invention can be used in a management method for incineration equipment that incinerates sewage sludge. [Explanation of Symbols]

[0117] 1: Incineration System 10: Incineration equipment 14: Incinerator 20:Ash component measuring device 30: Chemical injection device 40: Control device 41: Ash component identification part 42: Indicator Value Calculation Unit 43: Drug infusion control unit

Claims

1. A method for managing an incineration facility that incinerates sewage sludge, A step to identify the ash components in the incinerated ash obtained by incinerating the aforementioned sewage sludge, and a step to identify the concentrations of Ca, Mg, P, and Al elements in the incinerated ash, An index value calculation step is performed to calculate an index value I shown in the following formula (2) based on the concentration of each element identified in the ash component identification step, A method for managing an incineration facility, comprising: a chemical injection step of injecting a chemical into the sewage sludge based on the aforementioned index value I. Index value I: M P-Al / (M P-Al + M Ca + M Mg) (2) Here, in equation (2), M P-Al, M Ca, and M Mg are indices that depend on the concentrations of element P and Al, respectively, an index that depends on the concentration of element Ca, and an index that depends on the concentration of element Mg.

2. The method for managing an incineration facility according to claim 1, wherein the index value I shown in formula (2) is calculated based on the following formula (3). Index value I: (am Ｐ - bm Ａｌ ) / (am Ｐ - bm Ａｌ +cm Ｃａ +dm Ｍｇ ) ... (3) Here, in formula (3), m Ｐ , m Al , m Ｃａ , m Ｍｇ are the molar concentrations (mol / kg) of P element, Al element, Ca element, and Mg element in the incineration ash, and a to d are predetermined coefficients.

3. The ash component identification step further includes identifying the concentration of Fe element in the incineration ash, The method for managing an incineration facility according to claim 1, wherein the chemical injection step is a step of injecting the chemical into the sewage sludge when the following formula (4) is satisfied. α×(index value I) + β>M Ｆｅ ・・・(4) Here, in equation (4), the coefficient α is a predetermined value within the range of 4.0 to 6.0, and the coefficient β is a predetermined value within the range of -3.0 to 0.

0. Ｆｅ This is an index that depends on the concentration of the element Fe.

4. Said M Ｆｅ However, the method for managing an incineration facility according to claim 3, as shown in formula (5) below. M Ｆｅ =em Ｆｅ ・・・(5) Here, in equation (5), m Ｆｅ is the molar concentration (mol / kg) of element Fe in the incinerated ash, and e is a predetermined coefficient.

5. The method for managing an incineration facility according to any one of claims 1 to 4, wherein the aforementioned agent comprises a compound containing one or more metal elements selected from the group consisting of Fe, Ca, Mg, and Al.

6. Incineration facility for incinerating sewage sludge, An ash component measuring device for measuring the components of incinerated ash obtained by incinerating the aforementioned sewage sludge, A chemical injection device for injecting chemicals into the aforementioned sewage sludge, An incineration treatment system comprising a control device that controls the chemical injection device based on the measurement results from the ash component measuring device, The control device, The ash component identification unit identifies the concentrations of Ca, Mg, P, and Al elements in the incinerated ash measured by the ash component measuring device, Based on the concentrations of each element identified by the aforementioned ash component identification unit, an index value calculation unit calculates an index value I shown in the following formula (2), An incineration system comprising: a drug injection control unit that causes the drug injection device to inject the drug based on the index value I; and Index value I: M P-Al / (M P-Al + M Ca + M Mg) (2) Here, in equation (2), M P-Al, M Ca, and M Mg are indices that depend on the concentrations of element P and Al, respectively, an index that depends on the concentration of element Ca, and an index that depends on the concentration of element Mg.

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