JP2022069723A - Incinerator blockage risk evaluation method and incinerator blockage prevention method - Google Patents

Abstract

To provide an incinerator blockage risk evaluation method and an incinerator blockage prevention method capable of effectively preventing incinerator blockage.SOLUTION: An incinerator blockage risk evaluation method and an incinerator blockage prevention method include a pseudo-incinerator ash creation step (S100) to create the pseudo-incinerator ash PASH to be evaluated from sludge before feeding to the incinerator, a color data acquisition step (S110) to acquire RGB values of the pseudo-incinerator ash PASH, a calculation step (S120) to calculate R/(R+G+B) values from the RGB values, and an evaluation step (S150) to evaluate blockage risk based on correlation between blockage inhibition index of the pseudo-incinerator ash and the R/(R+G+B) values of the pseudo-incinerator ash. The evaluation step (S150) evaluates that there is a risk of obstruction when the obstruction suppression index, which is calculated by substituting the R/(R+G+B) value into the correlation, is below the first threshold value or when the R/(R+G+B) value is below the second threshold value.SELECTED DRAWING: Figure 2

Description

The present invention relates to an incinerator blockage risk evaluation method for evaluating the risk of blockage in an incinerator that incinerates sewage sludge, and an incinerator blockage prevention method for preventing blockage of the incinerator based on the evaluation.

The sewage sludge generated when purifying sewage at a sewage treatment plant is dehydrated and then incinerated in an incinerator for treatment. However, in recent years, there have been many reports of a phenomenon in which incineration ash obtained by incinerating sewage sludge adheres to a flue and the flue is blocked (blockage of an incinerator). Incinerator blockage includes phosphorus compounds with a melting point lower than the combustion temperature of the incinerator, depending on the balance of the abundance of phosphorus and metals in the sewage sludge charged into the incinerator. It is speculated that the main cause is the fusion of incinerator ash to the flue. In order to prevent such a phenomenon, the amount of phosphorus that can be bound by multiple refractory metal elements that can form a phosphorus compound with a melting point higher than the combustion temperature of the incinerator and the incineration ash that incinerated sewage sludge An index called "blockage suppression index X" consisting of the content of phosphorus contained is introduced, and the blockage suppression index (blockage suppression index value) is obtained from the results of component analysis of sewage sludge and incinerator, and the blockage suppression is performed. A chemical for suppressing ash adhesion in an incinerator based on an index value (for example, polysulfate second, which is a kind of chemical containing a refractory metal element capable of forming a phosphorus compound having a melting point higher than the combustion temperature of the incinerator. An incinerator blockage risk evaluation method and an incinerator blockage prevention method for controlling the addition of iron “= poly iron”) are known (see, for example, Patent Document 1).

In addition, the incinerator blockage risk that controls the addition of chemicals to sewage sludge by evaluating the blockage risk of the incinerator based on the color of the incinerator using the correlation between the color of the incinerator and the blockage suppression index value. Sex evaluation methods and incinerator blockage prevention methods are also known (see, for example, Patent Document 1). Specifically, the incinerator is closed based on the standard color, which is the color of the incinerator corresponding to the blockage suppression index, which is the standard for preventing the blockage of the incinerator, and the color of the incinerator incinerated in the incinerator. Evaluate the hazard and control the addition of chemicals to sewage sludge before incineration. According to such a conventional method, it is possible to evaluate the incinerator blockage risk by simply inspecting the color of the incinerator incinerator without waiting for the component analysis of the incinerator, and the sewage sludge. The addition of the drug to the sewage can be controlled.

Japanese Patent No. 5881260

However, conventional methods such as those described above control the addition of chemicals to pre-incinerator sewage sludge based on the blockage risk assessed based on the color of the incinerator incinerator ash, but sewage sludge. Since the properties of the incinerator are changing from moment to moment, there is a risk that the properties of the incinerator ash used for evaluation and the properties of the sewage sludge to which the chemicals are added do not match. In such a case, the accuracy of the incinerator blockage risk assessment is lowered, and it becomes difficult to control the addition of the chemical to the sewage sludge.

The present invention has been made in view of the above problems, and evaluates the risk of incinerator blockage when incinerating sewage sludge with high accuracy by a simple and quick method, and incinerates based on the evaluation. It is an object of the present invention to provide an incinerator blockage risk evaluation method and an incinerator blockage prevention method that can effectively prevent the blockage of the furnace.

(1) The incinerator blockage risk evaluation method according to the embodiment for achieving the above object is an incinerator blockage risk evaluation method for evaluating the blockage risk of an incinerator that incinerates sewage sludge. A part of the sewage sludge before being supplied to the incinerator is taken out, and the sewage sludge is subjected to a pseudo incinerator treatment to produce a pseudo incinerator ash to be evaluated. A plurality of samples were prepared in advance, a color data acquisition step of acquiring an RGB value as color data of the pseudo incinerator ash, a calculation step of calculating an R / (R + G + B) value from the RGB value of the pseudo incinerator ash to be evaluated. The bondable amount of phosphorus contained in the pseudo-incinerator and capable of forming a phosphorus compound having a melting point higher than the combustion temperature of the incinerator and capable of binding a plurality of refractory metal elements, and the phosphorus contained in the pseudo-incinerator. The blockage of the incinerator is based on the correlation between the blockage suppression index, which is the ratio of the inclusion amount of, and the R / (R + G + B) value obtained from the RGB values of the plurality of sampled pseudo incinerators. In the evaluation step, the blockage suppression index determined by substituting the value of R / (R + G + B) calculated by the calculation step into the correlation is the first. When it is below one threshold, or the value of R / (R + G + B) is the value of R / (R + G + B) determined by substituting the first threshold as the blockage suppression index into the correlation. If it is below the second threshold, it is evaluated that there is a risk of clogging of the incinerator.
(2) In the incinerator blockage risk evaluation method according to another embodiment, preferably, a plurality of the sewage sludge before being supplied to the incinerator is subjected to the pseudo incinerator treatment prior to the evaluation step. A sample color data acquisition step for acquiring the color data of the pseudo incinerator ash sample, a sample index acquisition step for acquiring the blockage suppression index based on the measured value of the component analysis of the sample, and the sample obtained from the sample. The correlation creation step for creating the correlation may be performed using the blockage suppression index and the color data obtained from the sample.
(3) In the incinerator blockage risk evaluation method according to another embodiment, preferably, in the pseudo incinerator ash preparation step, a part of the dehydrated sludge obtained by dehydrating the sewage sludge is taken out, and the dehydrated sludge is taken out by a pseudo combustion device. May be burned to produce the pseudo-incinerator ash.
(4) The incinerator blockage prevention method according to one embodiment is an incinerator blockage prevention method for preventing blockage of an incinerator based on the evaluation by any of the above-mentioned incinerator blockage risk evaluation methods, and the evaluation is described above. Based on the result of the step, when there is a risk of clogging of the incinerator, an addition step of adding a chemical containing a predetermined metal element for suppressing ash adhesion in the incinerator to the sewage sludge is performed.
(5) In the incinerator blockage prevention method according to another embodiment, preferably, in the addition step, the chemical may be added to the sewage sludge before it is put into the sludge dehydrator.
(6) In the incinerator blockage prevention method according to another embodiment, preferably, the pseudo incinerator ash may contain iron as the refractory metal element, and the chemical may contain ferric polysulfate.

According to the present invention, the risk of incinerator blockage when incinerating sewage sludge with high accuracy is evaluated by a simple and quick method, and the blockage of the incinerator based on the evaluation is effectively prevented. It is possible to provide an incinerator blockage risk assessment method and an incinerator blockage prevention method.

FIG. 1 shows a block diagram of a part of a sewage treatment system of a treatment plant according to an embodiment. FIG. 2 shows a flowchart of an incinerator blockage risk evaluation method according to the first embodiment of the present invention. FIG. 3 shows an example of a graph showing the correlation between the blockage suppression index of pseudo incinerator ash and the value of R / (R + G + B). FIG. 4 shows an example of a graph showing the correlation between the blockage suppression index of incinerator ash and the value of R / (R + G + B). FIG. 5 shows a flowchart of the incinerator blockage risk evaluation method according to the second embodiment of the present invention. FIG. 6 shows a flowchart of the incinerator blockage prevention method according to the first embodiment of the present invention. FIG. 7 shows a flowchart of the incinerator blockage prevention method according to the second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below do not limit the invention according to the claims. Moreover, not all of the elements and combinations thereof described in the embodiments are essential for the solution of the present invention.

1. 1. Sewage treatment system First, the sewage treatment system of the treatment plant according to the embodiment will be described.

FIG. 1 shows a block diagram of a part of a sewage treatment system of a treatment plant according to an embodiment. The block diagram shown in FIG. 1 illustrates a part of the sewage treatment system of the treatment plant, which is related to the incinerator blockage risk evaluation method and the incinerator blockage prevention method according to the present invention. In the present embodiment, illustration and description of the sewage treatment system of the treatment plant, which is unnecessary for the description of the incinerator blockage risk evaluation method and the incinerator blockage prevention method according to the present invention, will be omitted.

The sewage treatment system 1 preferably includes a concentrated sludge storage tank 10, a concentrated sludge supply pump 12, a sludge dehydrator 14, a dehydrated cake transfer conveyor 16, a cake storage tank 18, a cake supply pump 20, and an incinerator. A 22; an air preheater 24, a filtration type dust collector 26, an ash transfer conveyor 28, and an ash hopper 30 are provided. Further, the sewage treatment system 1 preferably includes a pseudo incinerator 32 for producing pseudo incineration ash PASH from a part of sewage sludge before being supplied to the incinerator 22.

The concentrated sludge storage tank 10 is a tank that receives and stores liquid sludge (also referred to as "concentrated sludge") concentrated by a concentration tank (not shown) and / or a concentrator (not shown). The concentrator is preferably sludge settled in the first settling basin (corresponding to the first settling basin in "Sewerage Facility Planning / Design Guidelines and Explanations (Part 2) 2009 Edition" (Japan Sewerage Association)) (not shown). It is a tank for concentrating. The concentrator is preferably a surplus discharged from the second settling basin (corresponding to the final settling basin in "Sewerage Facility Planning / Design Guidelines and Explanations (Part 2) 2009 Edition" (Japan Sewerage Association)) (not shown). It is a device that concentrates sludge. The concentrated sludge supply pump 12 is a pump that supplies sludge stored in the concentrated sludge storage tank 10 to the sludge dehydrator 14. The concentrated sludge stored in the concentrated sludge storage tank 10 is preferably added with a chemical M for suppressing ash adhesion in the incinerator 22 when there is a risk of blockage of the incinerator 22. Details of the addition of the drug M will be described later.

The sludge dehydrator 14 is a device that dehydrates the sludge supplied from the concentrated sludge supply pump 12. The sludge dewatering machine 14 dewaters the liquid sludge supplied from the concentrated sludge supply pump 12 to dewater the clay-like dewatered sludge (also referred to as “cake” or “dehydrated cake”). Generate. The dehydrated cake is sent to the dehydrated cake transfer conveyor 16. The dewatered cake transport conveyor 16 is a conveyor that transports the dewatered cake sent from the sludge dehydrator 14 to the cake storage tank 18. The cake storage tank 18 is a tank for storing the dehydrated cake sent from the dehydrated cake transfer conveyor 16. The cake storage tank 18 stores the dehydrated cake for preferably 1 to 10 hours, more preferably 5 hours. The cake storage tank 18 preferably includes a quantitative feeder (not shown). The stored dehydrated cake is preferably sent to the cake supply pump 20 in fixed amounts via a quantitative feeder. The cake supply pump 20 is a pump that supplies a dewatered cake sent from the cake storage tank 18 in a fixed amount to the incinerator 22.

The incinerator 22 incinerates the dehydrated cake supplied from the cake supply pump 20. The combustion temperature of the incinerator 22 is, for example, 700 ° C. or higher and 900 ° C. or lower, preferably 850 ° C. or higher and 900 ° C. or lower. The air preheater 24 is a device that preheats air using high-temperature exhaust gas discharged from the incinerator 22. The preheated air is used by returning it for combustion in the incinerator 22. The filtration type dust collector 26 is a device that filters exhaust gas and separates it into smoke and ash (incinerator ash) ASH. The separated incinerator ash ASH is sent to the ash transfer conveyor 28. The ash transfer conveyor 28 is a conveyor that transfers the incinerator ash ASH sent from the filtration type dust collector 26 and sends it to the ash hopper 30. The ash hopper 30 is a tank for temporarily storing incinerator ash ASH.

The pseudo incinerator 32 is an apparatus for producing a pseudo incinerator ash PASH by incinerating a part of the dehydrated cake dehydrated by the sludge dehydrator 14. The pseudo incinerator 32 is not particularly limited as long as it is an apparatus such as a gas burner that can burn a dehydrated cake to produce a pseudo incinerator ash PASH. The combustion temperature by the pseudo incinerator 32 is, for example, 600 degrees or more and 900 degrees or less, preferably 700 degrees or more and 800 degrees or less. Details of the production of the pseudo incinerator ash PASH will be described later.

2. 2. Incinerator blockage risk evaluation method (first embodiment)
The incinerator blockage risk evaluation method according to the first embodiment of the present invention will be described.

FIG. 2 shows a flowchart of an incinerator blockage risk evaluation method according to the first embodiment of the present invention. FIG. 3 shows an example of a graph showing the correlation between the blockage suppression index of pseudo incinerator ash and the value of R / (R + G + B). FIG. 4 shows an example of a graph showing the correlation between the blockage suppression index of incinerator ash and the value of R / (R + G + B).

The incinerator blockage risk evaluation method according to the first embodiment is a method for evaluating the blockage risk of the incinerator 22 for incinerating sewage sludge. The incinerator blockage risk evaluation method according to this embodiment includes a pseudo incinerator ash preparation step (S100), a color data acquisition step (S110), a calculation step (S120), and a blockage suppression index determination step (S130). The first determination step (S140), the first evaluation step (S150), and the second evaluation step (S160) are included. Hereinafter, each step will be described. The blockage suppression index determination step (S130), the first determination step (S140), and the first evaluation step (S150) are examples of the evaluation steps of the present invention.

2.1 Pseudo incinerator ash preparation step (S100)
In the pseudo incinerator ash preparation step, a part of the dehydrated sludge that has been dehydrated from the sewage sludge before being supplied to the incinerator 22 is taken out, and the dehydrated sludge is subjected to a pseudo incinerator treatment to prepare a pseudo incineration ash PASH to be evaluated. It is a step to do. The pseudo incinerator process is a process of burning sewage sludge by the pseudo incinerator 32. More specifically, in the pseudo incinerator ash preparation step, first, a part of the dewatered cake sent from the sludge dehydrator 14 to the dewatered cake transfer conveyor 16 is taken out and crushed using a mixer (not shown). Then, in the pseudo incinerator ash preparation step, the crushed dehydrated cake is burned by the pseudo combustion device 32 to prepare the pseudo incinerator ash PASH. Grinding and burning may be reversed. As the pseudo-combustion device 32, for example, a muffle furnace can be used. The object to be burned is placed on the silica sand laid in the magnetic dish, and the silica sand is covered over the silica sand to burn the object. That is, the object to be burned is provided in the pseudo-combustion device 32 with its surroundings covered with silica sand. As a result, pseudo incinerator ash can be obtained in an environment close to that of the incinerator 22. The time from crushing the pseudo-incinerated ash PASH with a mixer to burning in the pseudo-combustion device 32 is preferably shorter than the time from storage in the cake storage tank 18 to incineration of the dehydrated cake in the incinerator 22.

2.2 Color data acquisition step (S110)
The color data acquisition step is a step of acquiring RGB values as color data of the pseudo incineration ash PASH to be evaluated. More specifically, in the color data acquisition step, first, the pseudo-incinerated ash PASH to be evaluated is placed in a photographing container and photographed with a digital camera. Then, the color data acquisition step acquires RGB values from the image of the pseudo incinerator ash PASH taken by the digital camera. The method for acquiring the RGB value of the pseudo incineration ash PASH is not particularly limited, but any point of the image of the pseudo incineration ash PASH taken with a digital camera using, for example, a known image editing software (for example, Microsoft Paint). The RGB value of may be acquired. In such a case, in the color data acquisition step, a plurality of arbitrary points in the image of the pseudo incinerator ash PASH may be selected, and the average value of the RGB values at the selected plurality of points may be acquired as color data. The RGB value is a numerical value for designating a color, and for example, the R value, the G value, and the B value are each designated in the range of 0 to 255. In the color data acquisition step, the photographing means of the pseudo incineration ash PASH to be evaluated is not particularly limited as long as it is a means capable of acquiring image data, and may be, for example, a smartphone, a video camera, or the like. Further, the photographing container is not particularly limited as long as it is a container in which pseudo incinerator ash PASH is put and can be photographed by the photographing means.

2.3 Calculation step (S120)
The calculation step is a step of calculating the value of R / (R + G + B) from the RGB value of the pseudo incinerator ash PASH to be evaluated.

2.4 Blockage suppression index determination step (S130)
In the blockage suppression index determination step, the value of R / (R + G + B) calculated in the calculation step (S120) is converted into an equation (see FIG. 3) representing the correlation created by the correlation creation step (D120) described later. It is a step of substituting and determining the obstruction suppression index X.

The blockage suppression index X is also referred to as a blockage suppression index value, and there is a risk of incinerator ash adhering to the flue of the incinerator 22 that incinerates sewage sludge (and thus the risk of blockage of the incinerator 22 (risk of blockage of the incinerator). ) Is an index that quantitatively expresses. The blockage suppression index is the amount of phosphorus that can be bound to a plurality of refractory metal elements contained in the pseudo incinerator PASH and capable of forming a phosphorus compound having a melting point higher than the combustion temperature of the incinerator 22, and the pseudo incinerator ash. It can be calculated by the ratio of the inclusion amount of phosphorus contained in PASH (see the following formula (1)). Here, the "high melting point metal element" refers to a metal capable of forming a phosphorus compound having a melting point higher than the combustion temperature of the incinerator 22, and is preferably aluminum (Al), iron (Fe), calcium (Ca). And magnesium (Mg) can be exemplified. In the formula (1), Fe ₂ O ₃ is the mass fraction of Fe ₂ O ₃ of the pseudo incineration ash PASH, Al ₂ O ₃ is the mass fraction of Al ₂ O ₃ of the pseudo incineration ash PASH, and CaO is It is the mass fraction of CaO of the pseudo-incinerated ash PASH, MgO is the mass fraction of MgO of the pseudo-incinerated ash PASH, and P ₂ O ₅ is the mass fraction of P ₂ O ₅ of the pseudo-incinerated ash PASH. Further, M _(i) is the molecular weight or atomic weight [g / mol] of the compound i or the element i.

The molecule of the formula (1) shows the amount of phosphorus that can be bound to the specified plurality of metal elements (bondable amount). In the formula (1), the bondable amount indicates the number of moles of phosphorus that can be bound when the pseudo incinerator ash PASH is 100 [g]. Here, each term obtained by dividing the mass fraction of the compound in the molecule by the molecular weight of the compound indicates the number of moles of each compound when the total pseudo-incinerated ash PASH is 100 [g], and is multiplied by each of these terms. The coefficient indicates the number of mols of phosphorus required when the metal element contained in 1 mol of the compound corresponding to each term binds to phosphorus. For example, regarding the term corresponding to Fe ₂ O ₃ , 2 mol of Fe is present in 1 mol of Fe ₂ O ₃ , and when the expected phosphorus compound (FePO ₄ ) is produced, 2 mol of phosphorus is contained. Since it is necessary, the coefficient is set to 2. Similarly, regarding the term corresponding to CaO, 1 mol of Ca is present in 1 mol of CaO, and when the expected phosphorus compound (Ca ₃ (PO ₄ ) ₂ ) is produced, 2/3 mol of Ca is produced. Since phosphorus is required, the coefficient is set to 2/3. Further, the denominator of the formula (1) indicates the amount (inclusion amount) of phosphorus contained in the sewage sludge. In the formula (1), the inclusion amount indicates the number of moles of phosphorus when the pseudo incinerator ash PASH is 100 [g].

Here, the larger the clogging suppression index X is, the larger the bondable amount is relatively larger than the inclusion amount, and phosphorus is more likely to bind to the refractory metal element, and it is possible to form a phosphorus compound having a lower melting point. It gets lower. This means that when the sewage sludge is incinerated in the incinerator 22, the phosphorus compound having a low melting point becomes liquid and the possibility of adhering to each part of the incinerator 22 is reduced. Therefore, the blockage suppression index X can be used for evaluating the blockage risk of the incinerator 22.

As described above, based on the blockage suppression index X, the refractory metal is a refractory metal in view of the number of moles of Al, Fe, Ca, Mg and phosphorus (P) obtained by component analysis of the pseudo incinerator ash PASH. It can be evaluated that the risk of incinerator blockage is low (when the blockage suppression index X is large) when there is an excess of phosphorus with respect to phosphorus, and conversely, when these refractory metals are present in a small amount with respect to phosphorus. In some cases (when the blockage suppression index X is smaller than a predetermined reference value), it can be evaluated that the risk of blockage of the incinerator is high. For example, the risk of incinerator blockage can be evaluated based on whether the blockage suppression index X is less than 1.0.

2.5 First judgment step (S140)
The first determination step is a step of determining whether or not the obstruction suppression index X determined by the obstruction suppression index determination step (S130) is below the first threshold value. In this embodiment, the first determination step determines whether or not the blockage suppression index X is less than 1.0 as the first threshold value. The first threshold value is not limited to 1.0 and can be appropriately set, for example, 0.95, 1.12, and the like.

2.6 First evaluation step (S150)
The first evaluation step is a step of evaluating that there is a risk of blockage of the incinerator 22 when the blockage suppression index X is less than 1.0 (S140: Yes).

2.7 Second evaluation step (S160)
The second evaluation step is a step of evaluating that the risk of blockage of the incinerator 22 is low when the blockage suppression index X is not less than 1.0 (S140: No).

The incinerator blockage risk evaluation method according to this embodiment preferably includes a sample color data acquisition step (D100), a sample index acquisition step (D110), and a correlation creation prior to the pseudo incinerator ash preparation step (S100). Step (D120) and (see FIG. 2). Hereinafter, each step will be described. In the incinerator blockage risk evaluation method according to this embodiment, the sample color data acquisition step (D100), the sample index acquisition step (D110), and the correlation creation step (D120) are at least the blockage suppression index determination step ( If it is performed prior to S130), the timing is not particularly limited, and for example, it may be executed at the same time as the pseudo incinerator ash preparation step (S100), or the calculation step (S120) and the blockage suppression index determination step (S130). It may be executed between and. Further, if the sample color data acquisition step (D100) and the sample index acquisition step (D110) are performed prior to the correlation creation step (D120), there are no particular restrictions on the timing and order thereof, and the sample color data acquisition step (D100) and the sample index acquisition step (D110) are executed simultaneously, for example. Is also good.

In this embodiment, prior to the sample color data acquisition step (D100) and the sample index acquisition step (D110), m pieces (where m is an integer of 2 or more) are subjected to the same process as the pseudo incinerator ash preparation step (S100). A sample of pseudo-incinerated ash PASH is made. When sampling a plurality of pseudo incinerator ash PASH, it is preferable to prepare a plurality of samples in which the blockage suppression index X acquired by the sample index acquisition step (D100) described later is dispersed to some extent.

2.8 Sample color data acquisition step (D100)
The sample color data acquisition step is a step of acquiring color data of a sample of a plurality of pseudo incineration ash PASH produced by performing a pseudo incinerator treatment on sewage sludge before being supplied to the incinerator 22. More specifically, the sample color data acquisition step acquires the RGB values of each of the m pseudo-incinerator ash PASH samples by the same step as the color data acquisition step (S110). Further, in the sample color data acquisition step, preferably, the R / (R + G + B) value is calculated from the RGB values of each of the m simulated incinerator ash PASH samples.

2.9 Sample index acquisition step (D110)
The sample index acquisition step is a step of acquiring the blockage suppression index X based on the measured values of the component analysis of the sample of the pseudo incinerator ash PASH. More specifically, in the sample index acquisition step, component analysis is performed for each of the m simulated incinerator ash PASH samples, and the blockage suppression index X for each of the samples is based on the measured value of the component analysis and the formula (1). Is calculated. As the component analysis of the sample of the pseudo incinerator ash PASH, for example, a component analysis method by fluorescent X-ray analysis can be used.

2.10 Correlation creation step (D120)
The correlation creation step uses the blockage suppression index X obtained from the sample of the pseudo incinerator ash PASH and the value of R / (R + G + B) calculated from the RGB values of the sample, and the blockage suppression index in the pseudo incinerator ash PASH. This is a step of creating a correlation between and the value of R / (R + G + B) (see FIG. 3). For example, the correlation creation step creates an expression and a graph representing the correlation, as shown in FIG.

As shown in FIG. 4, there is a good correlation between the blockage suppression index based on the measured value of the component analysis of the incinerator ash ASH and the value of R / (R + G + B) calculated from the RGB value of the incinerator ash ASH. Is known to show. According to this correlation, the smaller the value of R / (R + G + B), the smaller the blockage suppression index. Therefore, the risk of blockage can be evaluated based on the value of R / (R + G + B) of the incinerator ash ASH. Further, according to the test study of the inventors, as shown in FIG. 3, the blockage suppression index based on the measured value of the component analysis of the pseudo-incinerator ash PASH and the R / (R + G + B) calculated from the RGB value of the pseudo-incinerator ash PASH. ), It was found that the same correlation as in the case of incinerated ash ASH (see FIG. 4) was shown. According to this correlation, as in the case of incinerator ash ASH, the smaller the value of R / (R + G + B), the smaller the blockage suppression index. Therefore, as in the case of the incinerator ash ASH, the blockage risk can be evaluated based on the R / (R + G + B) value of the pseudo incinerator ash PASH.

According to such an incinerator blockage risk evaluation method, a pseudo incinerator PASH is prepared from a part of the sewage sludge before being supplied to the incinerator 22, and the R / (R + G + B) value of the pseudo incinerator PASH is obtained. Is substituted into an equation (see FIG. 3) representing the correlation between the blockage suppression index in the pseudo incinerator ash PASH and the value of R / (R + G + B) to determine the blockage suppression index X in the pseudo incinerator ash PASH. As described above, between the blockage suppression index in the pseudo incinerator ASH PASH and the value of R / (R + G + B), the correlation between the blockage suppression index in the incinerator ash ASH and the value of R / (R + G + B) is as good as. Correlation is shown. Therefore, according to the incinerator blockage risk evaluation method, by using the correlation between the blockage suppression index in the pseudo incinerator PASH and the value of R / (R + G + B), it is not necessary to wait for the component analysis of the pseudo incinerator PASH. By simply acquiring the RGB value of the pseudo incinerator PASH and calculating the value of R / (R + G + B), the blockage suppression index X of the pseudo incinerator PASH can be determined with high accuracy, and the blockage of the incinerator 22 can be determined. The danger can be assessed.

In addition, the properties of sewage sludge change from moment to moment, and in particular, the properties of sewage sludge (dehydrated cake) may change while being stored in the cake storage tank 18 for a predetermined time. For example, the incinerated ash ASH taken out from the ash hopper 30 has passed at least a predetermined time from the time when it was stored in the concentrated sludge storage tank 10 to which the drug M is added. When the ash ASH is taken out from the ash hopper 30, it may differ from the properties of the sewage sludge stored in the concentrated sludge storage tank 10. However, according to the incinerator blockage risk evaluation method, the pseudo-incinerator ash PASH to be evaluated is made from a part of the dehydrated cake before being supplied to the cake storage tank 18, so that the properties of the pseudo-incinerator ash PASH are Compared to the properties of incinerator ASH, it is close to the properties of sewage sludge (concentrated sludge in the concentrated sludge storage tank 10) to which the drug M is added. Therefore, according to the incinerator blockage risk evaluation method, it is possible to evaluate the risk of blockage of the incinerator 22 when incinerating sewage sludge with high accuracy by a simple and quick method. That is, color data is acquired from the incinerator ASH that has passed through the incinerator 22 as in the conventional case, and the color data is applied to the correlation between the color data of the incinerator and the blockage suppression index (see FIG. 4) to incinerate the incinerator. Compared to evaluating the risk of blockage, as in the present embodiment, the dehydrated cake is incinerated by the pseudo incinerator 32 to prepare a pseudo incinerator ash PASH, and the color data is acquired and the pseudo incinerator ash is used. By applying the correlation between the color data and the blockage suppression index (see FIG. 3) to evaluate the incinerator blockage risk, the incinerator blockage risk can be grasped in a short time. This also applies to each subsequent embodiment.

(Second Embodiment)
Next, the incinerator blockage risk evaluation method according to the second embodiment of the present invention will be described. The same reference numerals are given to the parts common to the above embodiments, and duplicate explanations will be omitted.

FIG. 5 shows a flowchart of the incinerator blockage risk evaluation method according to the second embodiment of the present invention.

The incinerator blockage risk evaluation method according to the second embodiment has the same steps as the incinerator blockage risk evaluation method according to the first embodiment, but the blockage suppression index determination step (S130) and the first determination step ( It differs from the incinerator blockage risk evaluation method according to the first embodiment in that it includes a second determination step (S240) instead of S140).

The second determination step (S240) is a step of determining whether or not the value of R / (R + G + B) calculated by the calculation step (S120) is below the second threshold value. The second threshold value is R / (R + G + B) determined by substituting the first threshold value as the obstruction suppression index X into the equation representing the correlation created by the correlation creation step (D120) (see FIG. 3). Is the value of. In this embodiment, the second threshold value is 0.37. That is, the second determination step determines whether or not the value of R / (R + G + B) calculated by the calculation step (S120) is less than 0.37. The second threshold is not limited to 0.37 and can be appropriately set, for example, 0.35, 0.40, etc., based on the first threshold and the correlation. In the incinerator blockage risk evaluation method according to this embodiment, the sample color data acquisition step (D100), the sample index acquisition step (D110), and the correlation creation step (D120) are at least in the second determination step (S240). If done in advance, there are no particular restrictions on the timing. However, in this embodiment, it is preferable that the second threshold value is determined based on the correlation created by the correlation creation step (D120) prior to the second determination step (S240). The blockage suppression index determination step (S130), the second determination step (S240), and the first evaluation step (S150) are examples of the evaluation steps of the present invention.

Even in such an incinerator blockage risk evaluation method, the same effect as that of the above-described embodiment is obtained. Further, according to the incinerator blockage risk evaluation method according to this embodiment, if the second threshold value is determined based on the correlation created by the correlation creation step (D120) and the first threshold value, it is an evaluation target. It is possible to evaluate the blockage risk from the R / (R + G + B) value of the pseudo incinerator ash PASH to be evaluated without determining the blockage suppression index X of the pseudo incinerator ash PASH.

3. 3. Incinerator blockage prevention method (first embodiment)
The incinerator blockage prevention method according to the first embodiment of the present invention will be described.

FIG. 6 shows a flowchart of the incinerator blockage prevention method according to the first embodiment of the present invention.

The incinerator blockage prevention method according to the first embodiment causes the incinerator 22 to be blocked based on the evaluation of the blockage risk by the incinerator blockage risk evaluation method (see FIG. 2) according to the first embodiment described above. This is a way to prevent it. In the incinerator blockage prevention method according to this embodiment, an addition step (S170) is performed in addition to the incinerator blockage risk evaluation method (see FIG. 2) according to the first embodiment described above.

3.1 Addition step (S170)
The addition step is a step of adding the agent M to the sewage sludge when it is determined by the first evaluation step (S150) that there is a risk of clogging of the incinerator 22. The drug M is a drug containing a predetermined metal element for suppressing ash adhesion in the incinerator 22, and is preferably a drug containing at least one of the above-mentioned refractory metal elements. In this embodiment, iron is a refractory metal element, and the agent M preferably contains ferric polysulfate containing the iron (also referred to as "poly iron"). The agent M in this case may be polyiron itself or may contain polyiron in part. Polyiron is relatively inexpensive, easily available, and easy to handle. Therefore, it is possible to rationally prevent the incinerator from being blocked in terms of economy.

In the addition step, the agent M is preferably added to the sewage sludge before being charged into the sludge dehydrator 14, and more preferably to the concentrated sludge stored in the concentrated sludge storage tank 10. In this case, since the drug M is added at the closest possible position to the incinerator 22, the effect of the addition of the drug M can be directly enjoyed. By charging the chemical M in the concentrated sludge storage tank 10 close to the sludge dehydrator 14, the distance to the incinerator 22 can be shortened as much as possible, and thus the response time of the chemical charging effect can be shortened. Further, for example, when polyiron or the like is used as the chemical M, the equipment may be corroded by acid, and the concentrated sludge stored in the concentrated sludge storage tank 10 immediately before being put into the sludge dehydrator 14 If the drug M is added to the incinerator M, the section of the incinerator 22 can be shortened from the position where the drug M is added to the shortest, so that the above-mentioned section where there is a possibility of corrosion can be shortened to the shortest. For the above reasons, it is more preferable that the agent M is added in the concentrated sludge storage tank 10 immediately before being charged into the sludge dehydrator 14.

According to such an incinerator blockage prevention method, when there is a risk of blockage by the incinerator blockage risk evaluation method (see FIG. 2) according to the first embodiment described above, the sludge dehydrator 14 is charged. The drug M is added in the concentrated sludge storage tank 10 immediately before. Therefore, it is possible to prevent the incinerator 22 from being blocked when incinerating sewage sludge with high accuracy by a simple and quick method.

(Second Embodiment)
Next, the incinerator blockage prevention method according to the second embodiment of the present invention will be described. The same reference numerals are given to the parts common to the above embodiments, and duplicate explanations will be omitted.

FIG. 7 shows a flowchart of the incinerator blockage prevention method according to the second embodiment of the present invention.

The incinerator blockage prevention method according to the second embodiment causes the incinerator 22 to be blocked based on the evaluation of the blockage risk by the incinerator blockage risk evaluation method (see FIG. 5) according to the second embodiment described above. This is a way to prevent it. In the incinerator blockage prevention method according to this embodiment, an addition step (S170) is performed in addition to the incinerator blockage risk evaluation method (see FIG. 5) according to the second embodiment described above. Since the addition step (S170) is the same as the addition step (S170) of the incinerator blockage prevention method according to the first embodiment, detailed description thereof will be omitted. According to such an incinerator blockage prevention method, when there is a risk of blockage by the incinerator blockage risk evaluation method (see FIG. 5) according to the second embodiment described above, the sludge dehydrator is charged. The drug M is added in the concentrated sludge storage tank 10 immediately before. Therefore, it is possible to prevent the incinerator 22 from being blocked when incinerating sewage sludge with high accuracy by a simple and quick method.

4. Other Embodiments As described above, the embodiments of the present invention have been described, but the present invention is not limited to these, and can be variously modified and implemented.

For example, in each of the above-described embodiments, it is premised that a human performs the work of taking out a part of the dehydrated cake in order to prepare the pseudo-incinerator ash PASH to be evaluated in the pseudo-incinerator ash preparation step (S100). (In FIG. 1, the flow line is shown by a broken line). However, the present invention is not limited to this, and for example, it may be mechanized / automated without human involvement.

Further, in each embodiment of the above-mentioned incinerator blockage prevention method, it is premised that the addition of the drug M in the addition step (S170) is performed by a human (the flow line is shown by a broken line in FIG. 1). However, the present invention is not limited to this, and for example, it may be mechanized / automated without human involvement.

Further, in each of the above-described embodiments, the correlation created by the correlation creation step (D120) may be stored in a storage means (not shown) such as a RAM (Random Access Memory). In such a case, the sample color data acquisition step (D100), the sample index acquisition step (D110), and the correlation creation step (D120) may be omitted. That is, every time the pseudo incinerator ash PASH to be evaluated is prepared, the correlation does not have to be created prior to the evaluation of the blockage risk of the pseudo incinerator ash PASH to be evaluated. Further, every time a predetermined period elapses after the correlation is created by the correlation creation step (D120), a sample color data acquisition step (D100), a sample index acquisition step (D110), and a correlation creation step (D120) are newly created. ) May be executed to update the correlation stored in the storage means at any time.

The present invention can be used to assess the risk of blockage of an incinerator. The present invention can also be used to prevent blockage of the incinerator.

1 ... Sewage treatment system, 14 ... Sludge dehydrator, 22 ... Incinerator, 32 ... Pseudo incinerator, M ... Chemicals, PASH ... Pseudo incinerator ash, X ... Closure Sewage index.

Claims (6)

It is an incinerator blockage risk evaluation method that evaluates the blockage risk of an incinerator that incinerates sewage sludge.
A pseudo-incineration ash preparation step of taking out a part of the sewage sludge before being supplied to the incinerator and performing a pseudo-incineration treatment on the sewage sludge to produce a pseudo-incineration ash to be evaluated.
A color data acquisition step for acquiring RGB values as color data of the pseudo-incinerated ash to be evaluated, and
A calculation step for calculating the value of R / (R + G + B) from the RGB value of the pseudo incinerator ash to be evaluated, and
The amount of phosphorus that can be bound to a plurality of refractory metal elements contained in the pseudo-incineration ash sampled in advance and capable of forming a phosphorus compound having a melting point higher than the combustion temperature of the incinerator, and the pseudo-incinerator. Based on the correlation between the blockage suppression index, which is the ratio of the inclusion amount of phosphorus contained in the ash, and the R / (R + G + B) value obtained from the RGB values of the plurality of sampled pseudo-incinerator ash. An evaluation step for evaluating the risk of blockage of the incinerator, and
Including
In the evaluation step, when the blockage suppression index determined by substituting the value of R / (R + G + B) calculated by the calculation step into the correlation is below the first threshold value, or the R /. When the value of (R + G + B) is lower than the second threshold value which is the value of R / (R + G + B) determined by substituting the first threshold value as the blockage suppression index into the correlation, the incinerator An incinerator blockage risk assessment method characterized by assessing the risk of blockage. Prior to the evaluation step,
A sample color data acquisition step for acquiring the color data of a plurality of samples of the pseudo-incineration ash produced by performing the pseudo-incineration treatment on the sewage sludge before being supplied to the incinerator.
A sample index acquisition step for acquiring the blockage suppression index based on the measured value of the component analysis of the sample, and
A correlation creation step for creating the correlation using the blockage suppression index obtained from the sample and the color data obtained from the sample, and
The incinerator blockage risk evaluation method according to claim 1, wherein the incinerator is blocked. The pseudo incinerator ash preparation step is characterized in that a part of the dehydrated sludge obtained by dehydrating the sewage sludge is taken out and the dehydrated sludge is burned by a pseudo combustion device to prepare the pseudo incinerator ash. The incinerator blockage risk assessment method described in. A method for preventing incinerator blockage, which prevents blockage of the incinerator based on the evaluation by the incinerator blockage risk evaluation method according to any one of claims 1 to 3.
Based on the result of the evaluation step, if there is a risk of clogging of the incinerator, an addition step of adding a chemical containing a predetermined metal element for suppressing ash adhesion in the incinerator to the sewage sludge is performed. An incinerator blockage prevention method characterized by this. The method for preventing incinerator blockage according to claim 4, wherein the addition step is to add the chemical to the sewage sludge before it is put into the sludge dehydrator. The method for preventing incinerator blockage according to claim 4 or 5, wherein the pseudo-incinerator ash contains iron as the refractory metal element, and the chemical contains ferric polysulfate.

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