JP2011013197A - Method and system for evaluating coal ash property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for properly evaluating coal ash, capable of contributing to the quality control of coal ash.SOLUTION: The method for evaluating coal ash properties includes the steps of determining influence items that specify the density of coal ash, Blaine value, flow value ratio, and activity index of coal ash for expressing the density, the Blaine value, the flow value ratio and the activity index, as a tentative estimate equation containing a predetermined coefficient via the particle size, the ash composition, the concentration of unburnt combustible contents, and the ash content of coal ash from the known actual measurement data, determining each of the coefficients; forming the tentatively estimated equation for estimating the density, the Blaine value, the flow value ratio, and the activity index, based on the particle size, the ash composition, the concentration of unburnt combustible contents, and the ash content of coal ash; and evaluating the properties of coal ash to be targeted.

Description

  The present invention relates to an evaluation method and evaluation system for coal ash properties, and is particularly useful when applied to quality control of coal ash produced by a pulverized coal-fired boiler.

  Coal ash generated in the boilers of pulverized coal-fired thermal power plants is currently being used effectively for cement clay substitutes and building materials. However, the amount of coal ash used for cement substitute materials for cement has almost reached its limit. Therefore, the expansion of new uses of coal ash has become an important issue. As a new application of coal ash, expansion to cement admixture and concrete admixture is promising.

  On the other hand, in pulverized coal-fired thermal power plants that form coal ash, the properties of coal ash vary widely because coal from various production areas is used. For this reason, in order to expand the application of coal ash as described above, it is important to perform quality control so that coal ash having properties suitable for the application can be supplied.

  In addition, patent document 1 exists as well-known literature regarding the general quality control of coal ash, for example.

JP 2002-221968 A

  It is important to know the properties of coal ash for quality control of coal ash, and especially when considering application to concrete admixture as its application, the fly ash for concrete JIS A 6201, which is the quality control standard, is used. It is preferable to consider the standard items of density, specific surface area, flow value ratio, and activity index. These properties are measured by an analyzer, but if they can be predicted in advance, data useful for quality control can be provided easily and accurately, and whether or not the coal ash is suitable for use promptly. This is because it can be judged.

  However, the fact that the density of coal ash is affected by the particle size of coal ash is known, but the parameters specifying the coal ash density, specific surface area, flow value ratio, activity index and coal ash properties The quantitative relationship with the meter is not known.

  If such a quantitative relationship can be known, the density, specific surface area, flow value ratio and activity index can be estimated for a specific coal ash.

  In view of the above points, the present invention can clarify the quantitative relationship between coal ash density, specific surface area, flow value ratio, activity index, etc. and coal ash properties, and contribute to quality control of coal ash. An object is to provide an evaluation method and an evaluation system for coal ash properties.

  The present invention that achieves the above object is based on the following knowledge. That is, it is known that the density of coal ash is affected by the ash particle size, and various coal ash properties may be estimated by correlation with the influence items based on the already measured ash particle size distribution. is there. In addition, the ash particle size distribution can be easily measured with a commercially available measuring device. Data on coal ash properties and loss on ignition (hereinafter also referred to as unburned component concentration) is usually managed at each pulverized coal-fired power plant. Measured and stored as

  Therefore, in the present invention, assuming that the coal ash properties, the ash particle size and the unburned component concentration are known, the density, specific surface area, flow value ratio and activity index, which are standard items of the quality control standard of coal ash, are assumed. The main impact items related to these were extracted, and quantitative correlation was examined.

The first aspect of the present invention that achieves the above-mentioned object based on the results of such examinations
While replacing the true density of coal ash with the estimated true density based on the content of each coal ash component and the virtual true density based on the true density of each coal ash component and the content of each coal ash component including a predetermined coefficient The density estimation formula for determining the density of coal ash formed by substituting the porosity of coal ash particles with the apparent porosity based on the average particle diameter of coal ash including a predetermined coefficient. In addition,
Measured value of coal ash density, content of each coal ash component obtained from coal ash properties, true density of each coal ash component, content of coal ash component, and measured value of particle size distribution of coal ash The average particle size obtained from the above is substituted to create an equation with the coefficient as an unknown, and by solving this equation, the coefficient is determined and the coefficient for estimating the coal ash density is determined. Form a density estimation formula,
Furthermore, from the measured value of each coal ash component content, the true density of each coal ash component, the content rate of the coal ash component, and the particle size distribution of the coal ash obtained from the coal ash properties of the coal ash being evaluated. The coal ash property evaluation method includes estimating the density of the coal ash by substituting the obtained average particle diameter into a corresponding item of the density estimation formula in which the coefficient is determined.

According to a second aspect of the present invention, in the method for evaluating coal ash properties according to the first aspect,
The particle size standard specific surface area obtained by dividing the particle surface area per volume determined by the particle size distribution of the coal ash by the density of the coal ash, and the unburnt concentration in the coal ash and the ash content in the coal including a predetermined coefficient The coefficient formed based on the apparent shape factor based on the surface area average particle size related to the content rate and the particle size of coal ash is an undetermined specific surface area estimation formula,
The measured value of the specific surface area of coal ash, the particle surface area per volume obtained from the measured value of the particle size distribution of coal ash, the estimated or measured value of the density of coal ash, and the unburned component concentration in the coal ash Create an equation with the coefficient as an unknown by substituting the measured value, the ash content in the coal obtained from the coal ash properties, and the surface area average particle size obtained from the measured value of the particle size distribution of the coal ash. And solving the equation to determine the coefficient to form a specific surface area estimation formula with the coefficient determined to estimate the specific surface area of the coal ash,
Furthermore, the particle surface area per volume obtained from the actual measurement value of the particle size distribution of the coal ash to be evaluated, the estimated value or the actual measurement value of the density of the coal ash, the actual measurement value of the unburned matter concentration in the coal ash, Substituting the ash content in the coal determined from the coal ash properties and the surface area average particle size determined from the measured value of the particle size distribution of the coal ash into the corresponding items of the specific surface area estimation formula in which the coefficient was determined It is in the evaluation method of the coal ash property characterized by estimating the specific surface area of coal ash.

According to a third aspect of the present invention, in the method for evaluating coal ash properties according to the first or second aspect,
The unburned matter containing a predetermined coefficient and an apparent shape factor based on a surface area average particle size related to an unburned content concentration in coal ash, an ash content in coal, and a particle size of coal ash, and the unburned value including the predetermined coefficient Based on the partial concentration, the coefficient formed based on the uncertain flow value ratio estimation formula,
Surface area determined from the actual value of the flow value ratio of coal ash, the actual value of the unburned component concentration in the coal ash, the ash content in the coal determined from the coal ash properties, and the actual value of the particle size distribution of the coal ash Create an equation with the coefficient as an unknown by substituting the average particle size or the estimated apparent shape factor, and determine the coefficient by solving this equation to estimate the flow value ratio of the coal ash Forming a flow value ratio estimation formula in which the coefficient is determined;
Further, the actual value of the unburned component concentration of the coal ash to be evaluated, the ash content in the coal obtained from the coal ash properties, and the surface area average particle size obtained from the measured value of the particle size distribution of the coal ash, or were estimated The method for evaluating the coal ash properties includes substituting the apparent shape factor into a corresponding item of the flow value ratio estimation formula in which the coefficient is determined to estimate the flow value ratio of the coal ash.

According to a fourth aspect of the present invention, in the method for evaluating coal ash properties according to any one of the first to third aspects,
The coefficient formed based on the specific surface area of coal ash including a predetermined coefficient, the concentration of unburned coal in coal ash, and the content of alkali components in coal ash is an activity index estimation formula for which the coefficient is undetermined,
Create an equation with the coefficient as an unknown by substituting the measured value of the coal ash activity index, the measured or estimated value of the specific surface area of the coal ash, and the measured value of the unburned fuel concentration in the coal ash. , Solving the equation to determine the coefficient to form an activity index estimation formula with the coefficient determined to estimate the activity index of the coal ash,
Further, the estimated or measured value of the specific surface area of the coal ash to be evaluated and the measured value of the unburned component concentration in the coal ash are substituted into the corresponding items of the activity index estimation formula in which the coefficient is determined. It is in the evaluation method of coal ash properties characterized by estimating the activity index of coal ash.

According to a fifth aspect of the present invention, in the coal ash property evaluation method according to any one of the first to fourth aspects, the density is determined by the coefficients kd ₁ , kd ₂ , kd ₃ , and kd ₄ . The evaluation method for coal ash properties is characterized in that it is obtained using a density estimation formula obtained by substituting Formulas (1) and (2) into Formula (3).

According to a sixth aspect of the present invention, in the coal ash property evaluation method according to any one of the second to fourth aspects, the specific surface area is determined by coefficients ks ₁ , ks ₂ , ks ₃ , and ks ₄ . In the method for evaluating coal ash characteristics, the specific surface area estimation formula obtained by substituting Formula (4) and Formula (5) into Formula (6) is used.

According to a seventh aspect of the present invention, in the coal ash property evaluation method described in the third or fourth aspect, the flow value ratio is obtained as an equation (7) in which coefficients kf ₁ , kf ₂ , and kf ₃ are determined. It is in the evaluation method of the coal ash property characterized by calculating | requiring using the flow value ratio estimation formula.

According to an eighth aspect of the present invention, in the coal ash property evaluation method described in the fourth aspect, the activity index substitutes the formula (8) into the formula (9) and the coefficients ka ₁ , ka ₂ , ka _3, in the evaluation method of coal ash properties, characterized in that determined using ka ₄ activity index estimating equation obtained by determining the.

  According to a ninth aspect of the present invention, in the coal ash property evaluation method according to any one of the first to eighth aspects, each coefficient is determined by a least square method. It is in the evaluation method.

The tenth aspect of the present invention provides
Arithmetic processing provided with estimation formula storage means storing density estimation formula data for estimating the density of coal ash and density estimation means for performing calculation processing for the density based on the density estimation formula Means,
The estimation formula storage means includes a coal ash having an estimated true density based on a virtual true density based on a content rate of each coal ash component and a true density of each coal ash component, and a content rate of each coal ash component including a predetermined coefficient. For estimating the density of coal ash formed by substituting the porosity of coal ash particles with an apparent porosity based on the average particle diameter of coal ash including a predetermined coefficient The density estimation formula data formed by determining the coefficient in the density estimation formula whose coefficient is undetermined is stored,
The density estimating means includes the content of each coal ash component obtained from the coal ash properties relating to the coal ash to be evaluated, the true density of each coal ash component, the content of the coal ash component, and the particle size of the coal ash. The coal ash property evaluation system is characterized in that the density of the coal ash is estimated by substituting the average particle diameter obtained from the measured value of the distribution into the corresponding item of the density estimation formula.

The eleventh aspect of the present invention is the coal ash property evaluation system according to the tenth aspect,
The estimation formula storage means further stores specific surface area estimation formula data for estimating the specific surface area of coal ash, and the calculation processing means calculates for the specific surface area based on the specific surface area estimation formula. It further comprises a specific surface area estimation means for processing,
The specific surface area estimation formula includes a particle size standard specific surface area obtained by dividing the particle surface area per volume determined by the particle size distribution of the coal ash by the density of the coal ash, a predetermined coefficient, and unburned in the coal ash. The coefficient formed based on the partial concentration, the ash content in the coal, and the apparent shape factor based on the average surface area particle size related to the particle size of the coal ash is determined by determining the coefficient in the specific surface area estimation formula to be determined And
The specific surface area estimating means includes a particle surface area per volume obtained from an actual measurement value of a particle size distribution of coal ash to be evaluated, an estimated value or an actual measurement value of the density of coal ash, and an unburned component concentration in the coal ash. Substituting the actual measured value of, the ash content in the coal determined from the coal ash properties, and the average surface area particle size determined from the measured value of the particle size distribution of the coal ash into the corresponding items of the specific surface area estimation formula It is in the coal ash property evaluation system characterized by estimating the specific surface area of the coal ash.

The twelfth aspect of the present invention is the coal ash property evaluation system according to the tenth or eleventh aspect,
The estimation formula storage means further stores data of a flow value ratio estimation formula for estimating the flow value ratio of coal ash, and the calculation processing means estimates the flow value ratio based on the flow value ratio estimation formula. A flow value ratio estimating means for performing an arithmetic process for
The flow value ratio estimation formula includes a predetermined coefficient and an apparent shape factor based on an unburned component concentration in coal ash, an ash content in coal, and a surface area average particle size related to the particle size of coal ash, and The coefficient formed based on the unburned component concentration including a predetermined coefficient is determined by determining the coefficient in the undetermined flow value ratio estimation formula,
The flow value ratio estimating means is a surface area obtained from an actual measurement value of an unburned component concentration of coal ash to be evaluated, an ash content in coal obtained from the coal ash properties, and an actual measurement value of a particle size distribution of coal ash. The average particle size, or the estimated apparent shape factor and the actual measured value of the unburned component concentration are substituted into the corresponding item of the flow value ratio estimation formula, and the flow value ratio of the coal ash is estimated. It is in the evaluation system of coal ash properties.

A thirteenth aspect of the present invention is the coal ash property evaluation system according to any one of the tenth to twelfth aspects,
The estimation formula storage means further stores data of an activity index estimation formula for estimating the activity index of coal ash, and the calculation processing means estimates the activity index based on the activity index estimation formula Further comprising activity index estimation means for performing arithmetic processing for
The activity index estimation formula is based on the specific surface area of coal ash including a predetermined coefficient, the unburned component concentration in coal ash, and the content of the alkali component in coal ash. It is formed by determining the coefficient in the degree index estimation formula,
The activity index estimating means substitutes the estimated value or actual value of the specific surface area of the coal ash to be evaluated and the actual value of the unburned component concentration in the coal ash into the corresponding items of the activity index estimation formula. The coal ash property evaluation system estimates the activity index of the coal ash.

According to a fourteenth aspect of the present invention, in the coal ash property evaluation system according to any one of the tenth to thirteenth aspects, the density estimation formula includes coefficients kd ₁ , kd ₂ , kd ₃ , kd ₄ . The evaluation system for coal ash properties is obtained by substituting the determined equations (1) and (2) into equation (3).

A fifteenth aspect of the present invention is the coal ash property evaluation system according to any one of the eleventh to thirteenth aspects, wherein the specific surface area estimation formula is a coefficient ks ₁ , ks ₂ , ks ₃ , ks _4. The evaluation system for coal ash properties is obtained by substituting Equation (4) and Equation (5) for determining Equation (6) into Equation (6).

According to a sixteenth aspect of the present invention, in the coal ash property evaluation system described in the twelfth or thirteenth aspect, the flow value ratio estimation expression is an expression (7) in which coefficients kf ₁ , kf ₂ , and kf ₃ are determined. It is in the evaluation system of the coal ash property characterized by what is obtained as follows.

According to a seventeenth aspect of the present invention, in the coal ash property evaluation system described in the thirteenth aspect, the activity index estimation formula substitutes the formula (8) into the formula (9) and the coefficients ka ₁ and ka _2. , Ka ₃ , and ka ₄ are determined to obtain the coal ash property evaluation system.

  According to the present invention, the coal ash density, specific surface area, flow value ratio, and activity index of coal ash are assumed on the assumption that the coal ash properties, ash particle size, and unburned component concentration of the coal ash to be evaluated are known. The important impact items to be specified are extracted, the quantitative relationship with each impact item is expressed as a correlation equation including a predetermined coefficient, and the coefficient of each correlation equation is determined by existing data on coal ash. Based on the above, it is possible to form an estimation formula that accurately represents the density, specific surface area, flow value ratio, and activity index of coal ash by coal burned in a specific boiler.

  As a result, the density can be estimated by each estimation formula based on the coal ash properties, ash particle size and unburned content concentration, and the specific surface area, flow value ratio and activity index can be estimated sequentially using the estimated density. Data contributing to the evaluation of ash properties can be provided.

It is explanatory drawing which shows the relationship between the density, the brain value, flow value ratio, and activity index which are the evaluation items in embodiment of this invention, and each important influence item. It is a block diagram which shows the evaluation system of the coal ash property which concerns on embodiment of this invention. It is a block diagram which shows the structure of the coal combustion characteristic verification test measuring device used for the basic experiment of this invention. In density estimation, it is a characteristic figure which shows the relationship between the density and particle size of each coal ash regarding various coal. In density estimation, it is a characteristic view which shows the relationship between the density of coal ash, and a particle size. In estimation of the density, the density ratio indicating a ratio of the density was measured for the true density of the virtual is a characteristic diagram showing the relationship between the content of SiO ₂ and _{Al 2 O 3 (SiO 2 +} Al 2 O 3). In estimation of the density is a characteristic diagram showing the relationship between the ratio of SiO ₂ to density ratio and _{Al 2 O 3 (SiO 2 /} Al 2 O 3). In density estimation, it is a characteristic view which shows the comparison with an estimated value and an actual value regarding the precision using an estimation formula. It is a characteristic view which shows the correlation with a brane value and a particle size standard specific surface area. FIG. 6 is a characteristic diagram showing a correlation between an apparent shape factor and a surface area average diameter in the estimation of a brain value. FIG. 5 is a characteristic diagram showing the relationship between unburned component concentration and apparent shape factor in the estimation of the brane value. FIG. 6 is a characteristic diagram showing the relationship between the ash content and the apparent shape factor in the estimation of the brane value. FIG. 6 is a characteristic diagram showing a correlation between an estimated value of an apparent shape factor and an actually measured value in the estimation of a brain value. FIG. 5 is a characteristic diagram showing a correlation between an estimated value of a brain value obtained as a product of an estimated apparent shape factor and a particle size reference specific surface area and an actually measured value in the estimation of the brain value. FIG. 6 is a characteristic diagram showing a correlation between an estimated value of a brain value and an actual measurement value when each coefficient of the estimation formula is obtained without passing through an apparent shape factor in the estimation of the brain value. In the estimation of the flow value ratio, it is a characteristic diagram showing the relationship between the apparent shape factor and the flow value ratio. In estimation of flow value ratio, it is a characteristic figure which shows the relationship between flow value ratio and unburned-part density | concentration. In estimation of flow value ratio, it is a characteristic view which shows the correlation with the estimated value calculated | required using the apparent shape factor and the unburned ash concentration in ash, and an actual measurement value. FIG. 6 is a characteristic diagram showing the relationship between the brain value and the activity index in the estimation of the activity index. It is a characteristic view which shows the relationship between an activity index and unburned-part density | concentration in estimation of an activity index. FIG. 5 is a characteristic diagram showing the relationship between the activity index and the total content (% -weight) of CaO, MgO, Na ₂ O, and K ₂ O in the estimation of the activity index. FIG. 5 is a characteristic diagram showing a correlation between an estimated value of an activity index (28 days) and an actual measurement value in estimation of an activity index. In the estimation of the activity index, it is a characteristic diagram showing the correlation between the estimated value of the activity index (91 days) and the actual measurement value. In the estimation of the activity index, a characteristic diagram showing the correlation between the estimated value and the actually measured value when the coefficient of the correlation formula is obtained from the data of the activity index (28 days) and the correlation between the estimated value and the actually measured value is examined. is there. In the estimation of the activity index, it is a characteristic diagram showing the correlation between the estimated value of the brain value obtained by the estimation formula and the measured value. FIG. 6 is a characteristic diagram showing a correlation between an estimated value and an actual measurement value when an apparent shape factor is obtained from an estimated brain value and a flow value ratio is estimated based on the estimated brain value in the estimation of the activity index. FIG. 5 is a characteristic diagram showing a correlation between an estimated value of an activity index (28 days) obtained from an estimated brain value and an actual measurement value in estimation of an activity index. FIG. 5 is a characteristic diagram showing a correlation between an estimated value of an activity index (91 days) obtained from an estimated brain value and an actual measurement value in the estimation of the activity index.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  This form is based on the assumption that the coal ash properties, ash particle size, and unburned component concentration of the coal ash to be evaluated are known, the density of the coal ash, the specific surface area (hereinafter referred to as the brane value), and the flow value. The property of the coal ash is evaluated by obtaining the ratio and the activity index by a predetermined estimation formula. That is, the knowledge that the important influential items that define the density of coal ash are the ash particle size and ash composition of coal ash is obtained, and the quantitative relationship between the influential items and the density is mediated by a predetermined coefficient. It was expressed quantitatively by a predetermined estimation formula.

  Similarly, the important impact items that define the flow value ratio are the important impact items that define the brane value: the ash particle size of coal ash, the unburnt concentration in coal ash, and the ash content in coal. , Ash particle shape of coal ash, unburned component concentration in coal ash, important influence items that define the activity index are brane value, unburned component concentration in coal ash, base component The quantitative relationship between each influence item and the brain value, flow value ratio, and activity index was quantitatively expressed by a predetermined estimation formula using a predetermined coefficient as a medium.

  FIG. 1 shows the relationship among density, brain value, flow value ratio and activity index, which are evaluation items in this embodiment, and respective important influence items.

  In this embodiment, as indicated by arrows in FIG. 1, the brane value is estimated using the estimated density, and the flow value ratio and the activity index are estimated using the estimated brain value.

  Therefore, first, by measuring the particle size distribution and ignition loss (unburned component concentration in ash), density, brane value, flow value ratio, and activity index specified in JIS A 6201 for a specific coal ash. deep. Here, the particle size distribution was measured by an apparatus using a light diffraction / scattering method. The unburned component concentration, density, brane value, flow value ratio, and activity index were determined by the methods defined in JIS. The brane value is measured using the brane method, which is measured from the pressure loss when air is passed through the coal ash layer, and does not indicate the outer surface area of the true ash particles. Moreover, known data is used for the coal ash property (ash composition etc.) utilized for formation of the estimation formula in this form.

  Here, a specific estimation formula of density, brain value, flow value ratio, and activity index in this embodiment and an evaluation method using these will be described for each item.

1. Density Utilizing the fact that the important influential items that define the density of coal ash are the ash particle size and ash composition of coal ash, the quantitative relationship between these influential items and the density is mediated by a predetermined coefficient. Expression (10) is obtained by expressing quantitatively.

  The estimated true density in the above equation (10) is calculated based on the coal ash component content rate and the virtual true density of coal ash using the true density of each coal ash component, and each coal ash including a predetermined coefficient. It is obtained as equation (11) by the product with the component content.

Here, the ash component is SiO ₂ (2.2), 3Al ₂ O ₃ (3.1), Fe ₂ O ₃ (5.2), CaO (3.4), MgO based on the components in the composition analysis. (3.7), P ₃ O ₄ (2.4), TiO ₂ (4.2), Na ₂ O (2.3), K ₂ O (2.4) were used for approximation. The set true density is in parentheses. In the above equation (11), the virtual true density is obtained by the following equation.

  On the other hand, the apparent porosity in the above equation (10) is obtained as equation (12) by multiplying the volume average particle size of ash based on the particle size distribution of coal ash particles by a predetermined coefficient.

  As a result, by substituting the estimated true density obtained by Expression (11) and the apparent porosity obtained by Expression (12) into Expression (10), the predetermined coefficient is indefinite, but represents the density of coal ash. A temporary density estimation formula is obtained.

  This temporary density estimation formula replaces the true density of coal ash in the theoretical formula (detailed later) giving the density of coal ash with the estimated true density of formula (11), and the porosity is calculated by formula (12). It is a substitute for the apparent porosity.

In this embodiment, the density estimation formula is completed by determining the coefficients kd ₁ , kd ₂ , kd ₃ , and kd ₄ of the temporary estimation formula obtained by substituting the formulas (11) and (12) into the formula (10). That is, the measured density value of coal ash, the content of each coal ash component obtained from the coal ash properties, the true density of each coal ash component, and the measured value of the particle distribution of coal ash are calculated using the provisional density estimation formula. Is substituted for the above-mentioned coefficients kd ₁ , kd ₂ , kd ₃ , kd ₄ and the equations kd ₁ , kd ₂ , kd ₃ , kd ₄ are determined by solving these equations. The least square method is applied to determine the coefficients kd ₁ , kd ₂ , kd ₃ , and kd ₄ .

The density of the coal ash to be evaluated is determined based on the density estimation formula formed by determining the coefficients kd ₁ , kd ₂ , kd ₃ , and kd _4. The true density, the SiO ₂ content, the Al ₂ O ₃ content, and the volume average particle size are substituted into the corresponding items of the density estimation formula for estimation. Here, the content rate of each ash component, the true density of each ash component, the content rate of SiO ₂ , the content rate of Al ₂ O ₃ and the volume average particle size are measured values of coal ash properties and particle distribution regarding the coal ash. Ask based on.

2. Brain value Clarified that the important impact items that define the brane value are the ash particle size of coal ash, the unburned component concentration in coal ash, and the ash content in the coal ash. Equation (13) is obtained by quantitatively expressing the quantitative relationship with the above by a predetermined estimation formula using a predetermined coefficient as a medium.

  The particle size reference specific surface area in the above equation (13) is obtained as equation (14) by dividing the surface area per volume determined by the particle size distribution of coal ash by the density of coal ash.

  Here, the particle surface area per volume is calculated from the particle distribution on the assumption that the shape is a sphere.

  On the other hand, the apparent shape factor in the above equation (13) includes a predetermined factor and is based on the surface area average particle size related to the unburned component concentration in coal ash, the ash content in coal ash, and the particle size of coal ash. The value is obtained by equation (15).

  As a result, the predetermined coefficient is indefinite by substituting the particle size reference specific surface area obtained by Equation (14) and the apparent shape factor obtained by Equation (15) into Equation (13). A temporary brain value estimation formula representing the value is obtained.

In this embodiment, the brain value estimation formula is determined by determining the coefficients ks ₁ , ks ₂ , ks ₃ , and ks ₄ of the provisional brain value estimation formula obtained by substituting the formulas (14) and (15) into the formula (13). Form. That is, the measured value of the specific surface area of coal ash, the measured value of the particle size distribution of coal ash and the particle size standard specific surface area obtained from the density of coal ash, the measured value of unburned matter concentration in coal ash, the coal The coefficients ks ₁ , ks ₂ , ks ₃ are obtained by substituting the ash content in the coal determined from the ash properties and the surface area average particle size obtained from the measured value of the particle size distribution of the coal ash into the provisional brane value estimation formula , Ks ₄ is created as an unknown, and the coefficients ks ₁ , ks ₂ , ks ₃ , ks ₄ are determined by solving this equation. The least square method is applied to the determination of the coefficients ks ₁ , ks ₂ , ks ₃ , and ks ₄ .

The brane value of the coal ash to be evaluated is calculated using the brane value estimation formula formed by determining the coefficients ks ₁ , ks ₂ , ks ₃ , and ks ₄ . The unburned component concentration, the ash content rate, and the surface area average particle size are substituted into the corresponding items of the brain value estimation formula for estimation. Here, the particle surface area per volume of the coal ash, the density, the unburned content concentration, the ash content and the surface area average particle size are the coal ash properties, the measured particle distribution value, the estimated density value, the unburned content concentration Obtained based on actual measurement values. Moreover, although the measured value can be utilized regarding the density of coal ash, since the density is estimated using the density estimation formula as described above, it is reasonable to use this estimated value.

3. Flow value ratio It is clarified that the important influential items that define the flow value ratio are the ash particle shape of coal ash and the unburned component concentration in the coal ash. Equation (16) is obtained by quantitatively expressing such a relationship by a predetermined estimation formula using a predetermined coefficient as a medium.

In formula (16), although the predetermined coefficient is indefinite, a provisional flow value ratio estimation formula representing the flow value ratio of coal ash is obtained. Here, the apparent shape factor and the unburned component concentration are obtained by the equation (15) when the brane value is estimated, and the unburned component concentration is also obtained. Therefore, the coefficients kf ₁ and kf ₂ are used. , Kf ₃ is an unknown equation, and the coefficients kf ₁ , kf ₂ , and kf ₃ are determined by solving this equation. The least square method is applied for determining the coefficients kf ₁ , kf ₂ , and kf ₃ .

The flow value ratio to be evaluated is the flow value ratio estimation formula formed by determining the coefficients kf ₁ , kf ₂ , kf _3, and the apparent shape factor and unburned component concentration related to the coal ash Substituting into the corresponding item of the value ratio estimation formula, and estimating. Here, the apparent shape factor is the estimated value (see formula (15)) obtained when the brane value is estimated, and the unburned fuel concentration is the measured value applied when the brane value is estimated. it can.

4). Activity index It is clarified that the important influence items that define the activity index are the brane value, the unburned component concentration in the coal ash, and the base component, respectively. Equation (17) is obtained by quantitatively expressing such a relationship by a predetermined estimation formula using a predetermined coefficient as a medium.

  The ash alkali component content in the above formula (17) is obtained by the following formula (18) based on the coal ash properties.

As a result, by substituting the ash / alkaline component content obtained in equation (18) into equation (17), the predetermined coefficient is indefinite, but a temporary activity index estimation formula representing the activity index of coal ash is obtained. obtain. Here, the brane value has already been estimated, and the unburned component concentration has also been determined at the time of the estimation of the brane value. Therefore, these values are used and the alkali component content in the ash determined from the coal ash properties is used. An equation having coefficients ka ₁ , ka ₂ , ka ₃ , and ka ₄ as unknowns is created, and the coefficients ka ₁ , ka ₂ , ka ₃ , and ka ₄ are determined by solving this equation. The least square method is applied to the determination of the coefficients ka ₁ , ka ₂ , ka ₃ , and ka ₄ .

The activity index of the coal ash to be evaluated is calculated using the activity index estimation formula formed by determining the coefficients ka ₁ , ka ₂ , ka ₃ , and ka _4. The concentration and the alkali component content in the ash are estimated by substituting them into the corresponding items of the activity index estimation formula. Here, the brane value is the estimated value (see equation (13)), the unburned component concentration is the actual value applied in the estimation of the brane value, and the alkali component content in the ash is the coal ash property. Ask based on.

  FIG. 2 is a block diagram showing a coal ash property evaluation system according to an embodiment of the present invention. As shown in FIG. 1, the coal ash property evaluation system 1 according to the present embodiment includes an arithmetic processing unit 2, an estimation formula storage unit 3, an input device 4, and an output device 5. Here, the arithmetic processing unit 2 includes a density estimation unit 6, a brain value calculation estimation unit 7, a flow value ratio estimation unit 8, and an activity index estimation unit 9, which are stored in the estimation formula storage unit 3. By performing a predetermined calculation based on each estimation formula, the density, the brain value, the flow value ratio, and the activity index of the coal ash to be evaluated are estimated, and information about each estimated value is output to the output device 5. .

From the input device 4, information on the coal ash properties, the ash particle size, and the unburned component concentration of the coal ash that is the object of evaluation is supplied to the arithmetic processing unit 2. Here, in the estimation formula storage unit 3, formulas related to density estimation shown in formulas (10) to (12), formulas related to brane value estimation shown in formulas (13) to (15), and formula (16) are shown. Information relating to the estimation of the flow value ratio and information relating to the expression relating to the activity index shown in the equations (17) and (18) are stored, respectively, and related to the estimation equation for the predetermined estimation processing in each of the estimation units 6 to 9. Information is provided. At this time, the coefficients kd _{1 to} kd ₄ , ks _{1 to} ks ₄ , kf _{1 to} kf ₃ , and ka _{1 to} ka ₄ in each equation are separately given by the operation using the least square method as described above.

  Therefore, the density estimation unit 6 estimates the density of coal ash by performing a predetermined calculation based on the equations (10) to (12). The brain value estimation unit 7 estimates the brain value of coal ash by performing predetermined calculations based on the equations (13) to (15) using the density estimated by the density estimation unit 6. The flow value ratio estimation unit 8 estimates the flow value ratio of coal ash by performing a predetermined calculation based on Equation (16) using the apparent shape factor estimated by the brain value estimation unit 7. The activity index estimation unit 9 estimates the activity index of coal ash by performing predetermined calculations based on the equations (17) to (18) using the brain value estimated by the brain value estimation unit 7.

  Such a series of information processing may be executed by reading a program created as a program into the arithmetic processing unit 2, or may be executed by processing of an electronic circuit mounted as each functional block.

  The estimation formula as described above is based on knowledge based on the following test and analysis of the test result. Therefore, the test that is the basis of the present invention and the process of deriving the estimation formula based on the analysis result will be described.

[Test equipment and test method]
<Coal combustion characteristics demonstration test device>
FIG. 3 shows the configuration of a coal combustion characteristics demonstration test apparatus (hereinafter abbreviated as a demonstration test apparatus) used in this test. As shown in the figure, this demonstration test equipment is composed of pulverized coal production equipment, furnace, denitration equipment, electric dust collector (EP), desulfurization equipment and detoxification equipment (gas cooler, bag filter and alkali cleaning tower). Yes. In the pulverized coal production apparatus, coal stored in the raw coal hopper is pulverized and stored in a bottle. At the time of the test, the pulverized coal is conveyed by air and burned in the furnace by the combustion secondary / tertiary air and the two-stage combustion air.

The furnace is a vertical furnace with three upper, lower, and lower burners. The amount of fuel supplied to the furnace is about 100 kg / h per burner, and the whole furnace is about 300 kg / h. In this test, a low NO _x burner for pulverized coal (CI-α WR burner) was used.

  The exhaust gas after the combustion is cooled by an air heater and then flows into a denitration apparatus of an ammonia selective catalytic reduction method (SCR method). Thereafter, about 1/3 of the exhaust gas passes through two temperature controllers, and is then led to an electrostatic precipitator and a wet limestone-gypsum desulfurization apparatus.

  On the other hand, about 2/3 amount of exhaust gas is cooled by a water-cooled gas cooler, dust is removed by a bag filter, and then merged with about 1/3 amount of exhaust gas discharged from the desulfurization device, and desulfurized again by an alkali cleaning tower. After that, discharge from the chimney.

<Test method>
At the time of the test, first, the furnace was sufficiently preheated by burning A heavy oil, and then switched to coal. After that, it was confirmed that the temperature of each device became steady, and all the ash generated during preheating was removed.

  Thereafter, measurement under the set combustion conditions is started. Only the ash produced at this time was used as a sample.

  In order to evaluate the effects of ash particle size and unburned ash concentration on the estimated physical properties of the same coal brand in this test, the pulverized coal particle size is changed to 20 to 70 μm and the two-stage combustion rate is changed to 0 to 40%. The conducted tests were also conducted. Regarding the generated ash sample, the ash collected in the hoppers of the air heater, temperature controller, electric dust collectors 1-4, water-cooled gas cooler, and bag filter is removed. What was mixed by weight collection ratio was used.

<Measurement item and measurement method>
The measurement items of the generated coal ash were ash particle size distribution and unburned ash concentration, density, brane value, flow value ratio and activity index defined in JIS A 6201.

  The particle size distribution was measured with an apparatus using a light diffraction / scattering method. The unburned ash concentration, density, brane value, flow value ratio, and activity index were determined by methods defined in JIS.

  The brane value is measured using the brane method, which is measured from the pressure loss when air is passed through the product ash layer, and does not indicate the outer surface area of the true ash particles.

  The flow value ratio and the activity index are indicators for evaluating the application of coal ash to concrete admixture. Here, the flow value ratio is the ratio (%) of the flow value of the mortar mixed with coal ash to the flow value of the reference mortar without addition of coal ash. Therefore, if it is 100% or more, it has shown that fluidity | liquidity becomes better than a reference | standard mortar. The standard mortar is a mixture of 450 g of cement, 1,350 g of sand, and 225 g of water, and 25% of the cement is replaced with coal ash. The flow value is obtained by applying vibration to a cylindrical mortar and spreading it. The activity index indicates the ratio (%) of the compressive strength of the mortar mixed with coal ash to the compressive strength of the reference mortar without addition of coal ash. The activity index is obtained by cultivating a coal ash-mixed mortar under a predetermined condition and expressing it as a ratio of the breaking strength of the reference mortar. Two types are used: a value cured under predetermined conditions for 28 days and a value cured for 91 days. If it is 100% or more like the flow value, it indicates that the solidification is better than the reference mortar.

[Used charcoal properties]
<Characteristics of coal used in test study>
Table 1 shows the property range of the coal used in the demonstration test apparatus.

  In this test, 16 brands of bituminous coal were used. In terms of properties, fuel ratio (fixed carbon / volatile content) that affects flammability and unburnt content, ash content that affects ash particle size, ash composition that affects ash meltability and density Was selected to cover almost all the coal used in pulverized coal-fired power plants.

  In the examination of the results of this test, samples obtained from various test studies including combustion test under standard conditions, pulverized coal particle size change test, two-stage combustion rate change test and blended coal test are used in a comprehensive manner. Based on 42 ash samples. In addition, we used mainly coal ash at the time of exclusive combustion that burns a single brand without mixing different brands.

[Test results and discussion]
<Influence items on estimated physical properties and their correlation>
In examining the results of this test, the particle size distribution of ash that can be easily measured, the density of unburned ash used in combustion management, etc., and the density, brain value, and flow value of ash based on the properties of coal ash The purpose was to estimate the ratio and the activity index. The influence items were clarified and a correlation equation was constructed.

<Density>
(1) Impact items The impact items on the density, such as the particle size of coal ash, were examined.

1) Ash particle size The density of coal ash is affected by the density (true density) of the substances constituting the ash and the voids in the ash. In general, it is pointed out that the density tends to decrease as the particle size of ash increases. As a result of classifying coal ash and measuring its density, the present inventors have confirmed that the particle size is affected. That is, the larger the particle size, the more voids and the lower the density.

  Therefore, the same coal having the same ash component was used, the pulverized coal particle size was changed, ash having a different average particle size was generated, and the influence of the ash particle size was examined.

  Ash particles are mainly produced by fusion bonding of ash mineral particles in pulverized coal particles. Here, it is considered that the larger the number of bound minerals, the larger the particle size and the easier the formation of voids, which is related to the volume of the particles. Therefore, the volume average particle diameter Dv [μm] shown in Formula (19) was used as the average particle diameter used as an index.

  The relationship between the density and the generated ash particle size is shown in FIG. Referring to the figure, it can be seen that the density decreases as the particle size of ash increases regardless of the coal brand. In addition, when the pulverized coal particle size is changed, the influence of combustion is added in addition to the change in the number of bonds of mineral particles. The smaller the pulverized coal particle size, the more likely it is to burn, and the higher the temperature, the lower the voids. Therefore, in order to investigate the effect of combustibility, the effect of the two-stage combustion rate was also investigated. The results shown together with the effect of ash particle size in Fig. 4 are included in the data variability and do not show a clear effect. In our combustion test equipment, the effect is compared to the effect of ash particle size. Is considered small.

  Furthermore, the relationship between particle size and density was investigated based on ash data of various coal brands in a demonstration test device. As a result, as shown in FIG. 5, although the variation was large, the influence of the particle size was shown, and it was clarified that the particle size is a large influence item on the density.

2) Ash composition The ash composition that greatly affects the true density of ash was investigated. It is difficult to completely separate the effects of voids and true density on the density of ash. Here, it was decided to consider the true density based on the ash composition analysis value of coal specified in JIS. As oxides for estimating the density, SiO ₂ (2.2), 3Al ₂ O ₃ (3.1), Fe ₂ O ₃ (5.2), CaO (3.4), MgO (3.7) , P ₃ O ₄ (2.4), TiO ₂ (4.2), Na ₂ O (2.3), K ₂ O (2.4) without considering other substances such as SO ₃ , The sum of these was 100% -weight. The values in parentheses are the true oxide density (g / cm ³ ) set in this study. Further, since the aluminum component is mainly present in clay minerals such as kaolinite and illite, it was treated that mullite (3Al ₂ O ₃ .2SiO ₂ ) was generated.

On the other hand, SiO ₂ , which has a large content and is considered to have a strong influence on the density, has various crystal forms such as amorphous SiO ₂ and quartz, and the density is also different. In this examination, the value of amorphous SiO ₂ having a large generation ratio of coal ash was used.

The virtual true density ρa [g / cm ³ ] is obtained from the following equation (20).

In order to eliminate the influence of the particle size, ash having almost the same particle size was used for the examination. FIG. 6 shows the density ratio (−) indicating the ratio of the actually measured density to the virtual true density estimated by the equation (20), and the content ratio of SiO ₂ and Al ₂ O ₃ (SiO ₂ + Al ₂ O ₃ ) (% -Weight) relationship. If the virtual true density is the same as the actual density of the actual ash, the density ratio is constant regardless of the content, but a clear correlation was actually observed.

The characteristics shown in FIG. 6 indicate that the density ratio increases as SiO ₂ + Al ₂ O ₃ increases. If the virtual density is correct, the voids are affected and the voids are reduced. . According to past studies, if the content ratio of SiO ₂ and Al ₂ O ₃ increases, the melting point of ash and the viscosity at the time of melting increase, bubbles tend to remain inside, and the proportion of hollow particles (cenosphere) is increased. It has been shown to increase. For this reason, the influence on the air gap is unlikely.

On the other hand, the effect on the true density was treated as a single oxide except for mullite. Actually, an amorphous oxide in which various metals are solid-solved around SiO ₂ is produced, and this influence may be shown.

Further, as shown in FIG. 7, a correlation was also recognized with respect to the ratio of SiO ₂ to Al ₂ O ₃ (Al ₂ O ₃ / SiO ₂ ). Therefore, in this study, the oxide form changes depending on the ratio of SiO ₂ and Al ₂ O ₃ and is treated as an item affecting the true density.

3) Other influential items Other influential items may include ash content, ash meltability, and fuel ratio related to combustion, which affect the formation of voids in ash.

  However, in this study, the above items were not clearly shown. In order to clarify the influence of the ash particles on the voids, it is necessary to grasp the true density of the ash particles not including the voids.

  Moreover, as an influence on the density of ash, an influence of unburned matter having a density different from the true density of ash is also considered, but no influence was shown in the unburned matter concentration range of this study.

(2) Derivation of correlation equation and its accuracy Ash density ρash [g / cm ³ ] is a theoretical formula based on the true density ρt [g / cm ³ ] of the substance constituting ash and the porosity ε [−] of ash particles. Is expressed as the following equation (21).

  Next, it is considered that the ash composition affects the true density and the ash particle size affects the porosity. In addition, for each affected item, the function form is not clear, but when looking at the correlation with the affected item, it can be approximated by a linear relationship, and the affected item should be approximated by a linear line. It was. The correlation equation is shown in the following equation (22).

Regarding the accuracy of this correlation equation, the estimated value and the actually measured value were compared based on the coefficient kd _i obtained by using the least square method based on the data of the demonstration test apparatus.

  The correlation result is shown in FIG. From the results shown in the figure, it was shown that it can be estimated with a width of ± 3%. The R-2 power value indicating the strength of correlation was 0.76, indicating a strong correlation.

<Brain value>
(1) Influence item Although the brain value Sv [cm ² / g] does not indicate the surface area of the true ash particles in the measurement method, it is important as an index representing the specific surface area of the ash. The influence items were examined.

1) Ash particle size The brane value is considered to be closely related to the particle size of ash. Therefore, the specific surface area Sp is obtained by obtaining the surface area per volume from the particle size distribution of the ash on the assumption that the ash particles are spheres as shown in the equation (23), and dividing this value by the measured ash density. [cm ² / g] (hereinafter referred to as a particle size reference specific surface area) was determined.

  FIG. 9 shows the correlation between the brain value and the particle size reference specific surface area. The results shown in the figure showed that the correlation was weak. This is because the shape of ash particles is very different from that of a sphere, and this effect is considered to be strong. Thus, an apparent shape factor that is the ratio of the brane value to the particle size reference specific surface area was determined, and the relationship with the surface area average diameter Ds-ash [μm] determined by Equation (24) was examined.

As shown in FIG. 10, the apparent shape factor and the surface area average diameter have a strong correlation, and it can be seen that the apparent shape factor increases as the ash particle size increases. That is, the larger the particle size, the more the particles become distorted. Considering the generation of ash particles, as with the density of ash, the larger the ash particles, the greater the number of mineral particles bound together, and the more likely the particles are distorted.
As described above, it was found that the grain size of ash is a strong influence item on the brain value.

2) Concentration of unburned in ash Particles containing unburned matter are considered to contain ash, so the concentration of unburned ash in ash is low, but the effect is considered large. Therefore, the effect was examined in the range where the particle size of ash was almost the same. FIG. 11 shows the relationship between the unburned component concentration and the apparent shape factor. As shown in the figure, it was shown that the apparent shape factor increases as the unburned ash concentration increases, indicating that it is a strong influence item.

3) Ash content in coal The ash content affects the particle size of the ash. If the particle size of the pulverized coal is the same, if the ash content increases, the number of combined mineral particles increases. The particle size increases. As a result, the apparent shape factor is considered to increase. This effect is shown to be included in the effect of the ash particle size described above. On the other hand, if the ash particle diameter is the same, the influence of the ash content rate excluding the influence of the ash particle diameter may be shown. Then, the thing with the almost same particle diameter of ash was chosen, and the influence of the ash content rate was investigated. The relationship between the ash content and the apparent shape factor is shown in FIG. The figure shows that the effect of ash content is weak, but as the ash content increases, the apparent shape factor increases, indicating that the ash content needs to be considered as an influence item. .

  As for the effect of ash content, as the ash content increases, the proportion of mineral binding also increases and distortion tends to occur, and the proportion of large particles of ash (Exclude particles) that do not contain flammable components in pulverized coal It can be increased.

4) Other influential items Other influential items are the ash meltability related to the mineral composition in the pulverized coal particles and the influence of the fuel ratio and combustion conditions related to combustion. Regarding the meltability of ash, the influence of other influence items was strong, and the influence could not be confirmed clearly. On the other hand, regarding the fuel ratio and combustion conditions related to combustibility, if the fuel ratio changes, the unburned fuel concentration changes, and the effect is strongly shown. Changes and the effect appears. Thus, it was not possible to evaluate only the influence of combustibility.

(2) Derivation of correlation equation and its accuracy The brane value is greatly influenced by the shape of the particle, and is expressed using an apparent shape factor and a particle size reference specific surface area as shown in equation (25).

  From the above examination, the apparent shape factor is affected by the average surface area diameter, the unburned ash concentration and the ash content. The surface area average diameter was expressed as a power function because the linear relationship with the density was not clear.

  On the other hand, for the unburned ash concentration and the ash content, a linear correlation was obtained within the scope of this study, and the equation (26) was used as a correlation function with the apparent shape factor as a linear function. It was constructed.

  The correlation between the estimated value of the apparent shape factor and the actually measured value is shown in FIG. From this result, it was possible to estimate with an accuracy of ± 15%, and the R-squared value showed a strong correlation with 0.81.

  Next, FIG. 14 shows the correlation between the estimated value of the brane value obtained as the product of the estimated apparent shape factor and the particle size reference specific surface area, and the actually measured value. As shown in the figure, it was confirmed that the estimated brain value can be estimated with a width of ± 15% similar to the apparent shape factor. The R-2 power value was 0.46, which was lower than the R-2 power value of the apparent shape factor under the influence of the particle size standard specific surface area.

  Furthermore, the coefficient of each item was calculated | required directly by Formula (27), without passing through an apparent shape factor, and the estimated value and the measured value were compared.

  Also in this correlation, as shown in FIG. 15, it was shown that it can be estimated with an accuracy of ± 15% as in the case where the apparent shape factor is estimated. Moreover, there is no big difference in the R-2 power value. Based on this result, this study proposes a method for directly calculating the coefficient using equation (27) including the particle surface area.

<Flow value ratio>
(1) Influence item The flow value ratio is an index indicating the fluidity of mortar when coal ash is mixed, and the higher the fluidity, the larger the value. This influence item was examined.

1) Ash particle shape Mortar is composed of paste and fine aggregate (sand). The paste is a water slurry mixed with cement, coal ash, or the like. The fluidity of the mortar strongly affects the shape of the particles, and the fluidity is considered to decrease as the particles become distorted. Therefore, the relationship between the apparent shape factor and the flow value ratio was examined. The relationship between the apparent shape factor and the flow value ratio is shown in FIG. As shown in the figure, the flow value ratio decreased with an increase in the apparent shape factor, and it was confirmed that the shape of the particles had a great influence, and it became clear that this was a significant influence item.

2) Concentration of unburned ash In the study on the brane value, it was shown that the unburned ash content affects the particle shape. Moreover, since the particle | grains containing an unburned part are a shape and are porous, they may capture | acquire the water | moisture content which concerns on a flow, and may deteriorate fluidity | liquidity. Even in past studies, there is an example where the flow value ratio increases when the unburned component is removed. Therefore, in order to eliminate the influence of the shape, data having almost the same apparent shape factor was selected, and the influence of the unburned component concentration was examined.

  The relationship between the flow value ratio and the unburned component concentration is shown in FIG. As shown in the figure, it was confirmed that the flow value ratio became smaller as the unburned component concentration increased, and it became clear that this was an important influence item.

3) Other influence items The influence of the particle size distribution of ash is considered. Increasing the amount of free water by bringing the packed structure of the solid particles in the mortar closer to the closest packed structure and reducing the amount of water entering between the particles as much as possible leads to improved fluidity. When the apparent shape factor and unburned component concentration were almost the same, the correlation was examined, but no clear correlation was obtained. In addition, in order to clarify the influence of the particle size distribution of ash particles, it is necessary to consider the particle size distribution of cement particles and sand particles as well as removing unburned components.

(2) Derivation of correlation equation and its accuracy It was shown that the flow value ratio decreases as the apparent shape factor and unburned ash concentration increase. This influence item also has a linear relationship in this examination range, and is expressed by Equation (28) as a linear function with respect to the influence item.

  FIG. 18 shows the correlation between the estimated value obtained using the apparent shape factor and the unburned ash concentration and the actually measured value. From this result, it was shown that the flow value ratio can be estimated with an accuracy of ± 5%. The R-2 power value indicating the strength of the correlation was 0.66.

<Activity index>
(1) Influence item The amorphous oxide which has Si and Al as a main component in coal ash has a property which is easy to elute Si component and Al component in the pore solution of mortar. This eluted component reacts with calcium hydroxide derived from cement (Ca (OH) ₂ ) to form a hydrate such as calcium silicate hydrate which is hardly soluble in water, thereby increasing the concrete strength. This reaction is called a pozzolanic reaction. An index for evaluating the influence of solidification is an activity index. In order to strictly evaluate the effect on the activation index, it is necessary to investigate the reaction mechanism such as the ratio of amorphous substances. In this study, as described above, the coal ash properties, ash particle size The impact items will be examined in the range of unburned fuel concentration.

1) Blaine value It has been shown that the surface area of ash particles is greatly involved in the elution of Si and Al components from amorphous SiO ₂ and Al ₂ O _{3 in} coal ash. Tried. The relationship between the brain value and the activity index is shown in FIG. From the results shown in FIG. 19, it can be confirmed that the brain value affects the activity index.

2) Concentration of unburned ash in ash If the amount of unburned fuel increases, the ash content involved in the solidification reaction can be reduced. There is also a study that, though not clear, suggests that removing the unburned content may increase the activity index. Therefore, in order to avoid the influence of the brain value, those having approximately the same brain value were selected, and the influence was examined.

  FIG. 20 shows the relationship between the activity index and the unburned component concentration. The activity index showed a tendency to decrease as the unburned component concentration increased, and it became clear that it was an important influence item.

3) Base component It has been pointed out that the base component is involved in the formation of amorphous SiO ₂ and Al ₂ O ₃ involved in the solidification reaction and the elution of Si and Al components. Regarding the formation of amorphous SiO ₂ , there is a correlation with the molar ratio of K ₂ O to Al ₂ O ₃ , and it has been reported that the amorphous SiO ₂ increases as this molar ratio increases. On the other hand, with respect to elution and solidification, the greater the amount of CaO contained in the amorphous material, the higher the pozzolanic reactivity, and the greater the content of CaO, MgO, Na ₂ O, and K ₂ O, the greater the elution rate of Si. It has been reported to increase.

When the correlation between these indices and the activity index was examined, the relationship with the total content (% -weight) of CaO, MgO, Na ₂ O, and K ₂ O was most clearly shown as shown in FIG. It was.

4) Other correlation items As already mentioned, various substances are involved in the solidification reaction. Amorphous SiO ₂ and Al ₂ O ₃ that are important for the reaction are considered to be affected by the ash composition and combustion conditions, but are not considered in this study.

(2) Derivation of correlation equation and its accuracy The activity index has various influence items related to solidification of mortar, and within the scope of applicable items in this study, brane value, unburned ash concentration, CaO, MgO, Na It was clarified that it was influenced by the total content of ₂ O and K ₂ O. The brane value and the unburned ash concentration decrease the activity index and increase the total content of CaO, MgO, Na ₂ O and K ₂ O. These affected items also have a linear correlation in this examination range, and are approximately expressed by the equation (29) as a linear function with respect to the affected items.

  FIG. 22 shows the correlation between the estimated value of the activity index (28 days) and the actually measured value. From this result, it was shown that the activity index can be estimated with an accuracy of ± 5%. The R-2 power value indicating the strength of the correlation was 0.58.

  Next, FIG. 23 shows the correlation between the estimated value of the activity index (91 days) and the actually measured value. It was shown that it can be estimated with an accuracy of ± 5% similarly to the activity index (28 days). The R-squared value was 0.57, indicating a correlation strength similar to the activity index (28 days) of 0.58.

Moreover, since the brane value and unburnt content concentration of ash are physical property values reflecting the influence of combustion in the boiler, the total content of CaO, MgO, Na ₂ O, and K ₂ O is the property of ash. There is a possibility that it can be estimated regardless of the type of boiler. Therefore, as with the flow value ratio, the coefficient of the correlation equation was obtained from the activity index data (28 days) combining the demonstration test apparatus and the power plant boiler, and the correlation between the estimated value and the actual measurement value was examined. FIG. 24 shows the correlation between the estimated value and the actually measured value. As shown in the figure, it was confirmed that most of the data fits within an accuracy of about ± 5%. The R-square value indicating the strength of the correlation decreases to 0.80, but there is a sufficient correlation.

  As described above, the items affecting the density of ash, the brain value, the flow value ratio, and the activity index have been clarified, and the correlation equation was constructed based on the items. In this correlation equation, it was confirmed that the density can be estimated with an accuracy of ± 3%, the brain value is ± 15%, the flow value ratio is ± 5%, and the activity index is ± 5%.

<Estimation method>
Based on the above examination, the influence items on the density, the brain value, the flow value ratio, and the activity index are extracted based on the actually measured values, and the above equations (19) to (29) (the equations (10) to (18) in this embodiment are Equivalent).

  Then, using the density estimated based on the equations (19) to (22) (corresponding to the equations (10) to (12) in this embodiment), the equations (23) to (27) (equation (13) in this embodiment). FIG. 25 shows the correlation between the estimated value of the brain value obtained by the above (corresponding to (15)) and the actually measured value. As shown in the figure, the correlation accuracy in this case is approximately within ± 15%, and the R-2 power value is 0.76, which is almost the same as the value using the actual density shown in FIG. It was confirmed that the measured value can be estimated in the same manner as when the measured density was used.

  Next, an apparent shape factor was obtained from the estimated brain value, and based on this, the flow value ratio was estimated based on the equation (28) (corresponding to the equation (16) in this embodiment). FIG. 26 shows the correlation between the estimated value and the actually measured value in this case. As shown in the figure, it was confirmed that the correlation accuracy in this case was within about ± 5%. The R-2 power value was 0.66.

  Finally, the estimated value and actual value of the activity index (28 days) obtained by the formulas (28) and (29) (corresponding to the formulas (17) and (18) in this embodiment) using the estimated brain value The correlation is shown in FIG. The correlation accuracy was approximately within ± 5%, and the R-2 power value was 0.58.

  Next, FIG. 28 shows a correlation between a similar estimated value and an actually measured value of the activity index (91 days). As shown in the figure, as with the activity index (28 days), it was confirmed that the estimated value was within ± 5%. The R-2 power value is 0.54, which is similar to the value (0.58) of the demonstration test apparatus for the activity index (28 days), indicating that there is a sufficient correlation.

  Based on the assumption that the coefficient of the correlation equation in the demonstration test equipment has been obtained, the accuracy of the estimation was examined. Even if sequential calculation such as estimating the brain value using the estimated density is performed, it can be confirmed that it can be estimated with accuracy of density ± 3%, brain surface area ± 15%, flow value ratio and activity index ± 5%. It was.

<Summary>
The influence items on each estimated physical property clarified from the above experimental results and the examination results are as follows.

  It has been confirmed that the density decreases as the particle size increases, and that the voids in the ash particles tend to increase as the particle size increases. On the other hand, the density is affected by the true density of a substance constituting ash such as an amorphous oxide.

In view of this point, the present invention has proposed a correlation formula using SiO ₂ and Al ₂ O ₃ content ratios and SiO ₂ / Al ₂ O ₃ as indices as a density estimation formula.

  By using the “apparent shape factor” represented by the ratio of the brane value to the particle size reference specific surface area, the influence item became clear. This apparent shape factor was affected by the particle size, unburned component concentration, and ash content, and as a result, the number of particles having a distorted shape increased and the value decreased.

  In view of this point, the present invention has proposed a correlation equation using a particle size standard specific surface area and an apparent shape factor as a brain value estimation equation.

  The flow value ratio was affected by the apparent shape factor and unburned component concentration, and decreased as they increased. This is presumably because the distorted particles deteriorate the fluidity of the mortar, and the porous unburned component absorbs moisture and reduces the moisture involved in the flow.

  In view of this point, the present invention has proposed a correlation equation using an apparent shape factor and unburned component concentration as a flow value ratio estimation equation.

The activity index increased as the ash brane value and base component (CaO + MgO + Na ₂ O + K ₂ O) content increased in the solidification reaction. On the other hand, it decreased as the unburned component concentration increased. This is thought to be due to an increase in the carbon content not involved in the reaction as the unburned component concentration increases.

  Based on this point, the present invention has proposed a correlation formula using the brane value, the unburned component concentration, and the alkali component content in ash as the activity index estimation formula.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used in the electric power industry where coal ash is generated by a pulverized coal-fired boiler, the construction using the generated coal ash, the civil engineering industry, and the like.

DESCRIPTION OF SYMBOLS 1 Coal ash property evaluation system 2 Operation processing part 3 Estimation formula memory | storage part 6 Density estimation part 7 Brain value estimation part 8 Flow value ratio estimation part 9 Activity index estimation part

Claims (17)

While replacing the true density of coal ash with the estimated true density based on the content of each coal ash component and the virtual true density based on the true density of each coal ash component and the content of each coal ash component including a predetermined coefficient The density estimation formula for determining the density of coal ash formed by substituting the porosity of coal ash particles with the apparent porosity based on the average particle diameter of coal ash including a predetermined coefficient. In addition,
Measured value of coal ash density, content of each coal ash component obtained from coal ash properties, true density of each coal ash component, content of coal ash component, and measured value of particle size distribution of coal ash The average particle diameter obtained from the above is substituted to create an equation with the coefficient as an unknown, and by solving this equation, the coefficient is determined and the coefficient for estimating the coal ash density is determined. Form a density estimation formula,
Furthermore, from the measured value of each coal ash component content, the true density of each coal ash component, the content rate of the coal ash component, and the particle size distribution of the coal ash obtained from the coal ash properties of the coal ash being evaluated. A method for evaluating a coal ash property, comprising substituting the obtained average particle size into a corresponding item of a density estimation formula in which the coefficient is determined to estimate the density of the coal ash. In the evaluation method of the coal ash property according to claim 1,
The particle size standard specific surface area obtained by dividing the particle surface area per volume determined by the particle size distribution of the coal ash by the density of the coal ash, and the unburnt concentration in the coal ash and the ash content in the coal including a predetermined coefficient The coefficient formed based on the apparent shape factor based on the surface area average particle size related to the content rate and the particle size of coal ash is an undetermined specific surface area estimation formula,
The measured value of the specific surface area of coal ash, the particle surface area per volume obtained from the measured value of the particle size distribution of coal ash, the estimated or measured value of the density of coal ash, and the unburned component concentration in the coal ash Create an equation with the coefficient as an unknown by substituting the measured value, the ash content in the coal obtained from the coal ash properties, and the surface area average particle size obtained from the measured value of the particle size distribution of the coal ash. And solving the equation to determine the coefficient to form a specific surface area estimation formula with the coefficient determined to estimate the specific surface area of the coal ash,
Furthermore, the particle surface area per volume obtained from the actual measurement value of the particle size distribution of the coal ash to be evaluated, the estimated value or the actual measurement value of the density of the coal ash, the actual measurement value of the unburned matter concentration in the coal ash, Substituting the ash content in the coal determined from the coal ash properties and the surface area average particle size determined from the measured value of the particle size distribution of the coal ash into the corresponding items of the specific surface area estimation formula in which the coefficient was determined A method for evaluating the properties of coal ash, wherein the specific surface area of coal ash is estimated. In the evaluation method of the coal ash property according to claim 1 or claim 2,
The unburned matter containing a predetermined coefficient and an apparent shape factor based on a surface area average particle size related to an unburned content concentration in coal ash, an ash content in coal, and a particle size of coal ash, and the unburned value including the predetermined coefficient Based on the partial concentration, the coefficient formed based on the uncertain flow value ratio estimation formula,
Surface area determined from the actual value of the flow value ratio of coal ash, the actual value of the unburned component concentration in the coal ash, the ash content in the coal determined from the coal ash properties, and the actual value of the particle size distribution of the coal ash Create an equation with the coefficient as an unknown by substituting the average particle size or the estimated apparent shape factor, and determine the coefficient by solving this equation to estimate the flow value ratio of the coal ash Forming a flow value ratio estimation formula in which the coefficient is determined;
Further, the actual value of the unburned component concentration of the coal ash to be evaluated, the ash content in the coal obtained from the coal ash properties, and the surface area average particle size obtained from the measured value of the particle size distribution of the coal ash, or were estimated A method for evaluating a coal ash property, comprising substituting an apparent shape factor into a corresponding item of a flow value ratio estimation formula in which the coefficient is determined to estimate a flow value ratio of the coal ash. In the evaluation method of the coal ash property as described in any one of Claims 1 thru | or 3,
The coefficient formed based on the specific surface area of coal ash including a predetermined coefficient, the concentration of unburned coal in coal ash, and the content of alkali components in coal ash is an activity index estimation formula for which the coefficient is undetermined,
Create an equation with the coefficient as an unknown by substituting the measured value of the coal ash activity index, the measured or estimated value of the specific surface area of the coal ash, and the measured value of the unburned fuel concentration in the coal ash. , Solving the equation to determine the coefficient to form an activity index estimation formula with the coefficient determined to estimate the activity index of the coal ash,
Further, the estimated or measured value of the specific surface area of the coal ash to be evaluated and the measured value of the unburned component concentration in the coal ash are substituted into the corresponding items of the activity index estimation formula in which the coefficient is determined. An evaluation method for coal ash properties, characterized by estimating an activity index of coal ash. In the evaluation method of the coal ash property as described in any one of Claims 1 thru | or 4,
The density is obtained using a density estimation formula obtained by substituting Formulas (1) and (2) for determining the coefficients kd ₁ , kd ₂ , kd ₃ , and kd ₄ into Formula (3). Evaluation method for ash properties.

In the evaluation method of the coal ash property as described in any one of Claims 2 thru | or 4,
The specific surface area is obtained using a specific surface area estimation formula obtained by substituting Formula (4) and Formula (5) for determining the coefficients ks ₁ , ks ₂ , ks ₃ , and ks ₄ into Formula (6). Evaluation method of coal ash properties.

In the evaluation method of the coal ash property according to claim 3 or claim 4,
The method for evaluating coal ash properties, wherein the flow value ratio is obtained using a flow value ratio estimation formula obtained as an equation (7) for determining the coefficients kf ₁ , kf ₂ , and kf ₃ .

In the evaluation method of the coal ash property according to claim 4,
The activity index is obtained by substituting equation (8) into equation (9) and using an activity index estimation formula obtained by determining the coefficients ka ₁ , ka ₂ , ka ₃ , and ka _4. Evaluation method of coal ash properties.

In the evaluation method of the coal ash property as described in any one of Claims 1 thru | or 8,
Each coefficient is determined by the least square method. Arithmetic processing provided with estimation formula storage means storing density estimation formula data for estimating the density of coal ash and density estimation means for performing calculation processing for the density based on the density estimation formula Means,
The estimation formula storage means includes a coal ash having an estimated true density based on a virtual true density based on a content rate of each coal ash component and a true density of each coal ash component, and a content rate of each coal ash component including a predetermined coefficient. For estimating the density of coal ash formed by substituting the porosity of coal ash particles with an apparent porosity based on the average particle diameter of coal ash including a predetermined coefficient The density estimation formula data formed by determining the coefficient in the density estimation formula whose coefficient is undetermined is stored,
The density estimating means includes the content of each coal ash component obtained from the coal ash properties relating to the coal ash to be evaluated, the true density of each coal ash component, the content of the coal ash component, and the particle size of the coal ash. A coal ash property evaluation system characterized by substituting an average particle diameter obtained from an actual measurement value of distribution into a corresponding item of the density estimation formula to estimate the density of the coal ash. In the evaluation system of the coal ash property according to claim 10,
The estimation formula storage means further stores specific surface area estimation formula data for estimating the specific surface area of coal ash, and the calculation processing means calculates for the specific surface area based on the specific surface area estimation formula. It further comprises a specific surface area estimation means for processing,
The specific surface area estimation formula includes a particle size standard specific surface area obtained by dividing the particle surface area per volume determined by the particle size distribution of the coal ash by the density of the coal ash, a predetermined coefficient, and unburned in the coal ash. The coefficient formed based on the partial concentration, the ash content in the coal, and the apparent shape factor based on the average surface area particle size related to the particle size of the coal ash is determined by determining the coefficient in the specific surface area estimation formula to be determined And
The specific surface area estimating means includes a particle surface area per volume obtained from an actual measurement value of a particle size distribution of coal ash to be evaluated, an estimated value or an actual measurement value of the density of coal ash, and an unburned component concentration in the coal ash. Substituting the actual measured value of, the ash content in the coal determined from the coal ash properties, and the average surface area particle size determined from the measured value of the particle size distribution of the coal ash into the corresponding items of the specific surface area estimation formula A coal ash property evaluation system characterized by estimating a specific surface area of the coal ash. In the evaluation system of the coal ash property according to claim 10 or claim 11,
The estimation formula storage means further stores data of a flow value ratio estimation formula for estimating the flow value ratio of coal ash, and the calculation processing means estimates the flow value ratio based on the flow value ratio estimation formula. A flow value ratio estimating means for performing an arithmetic process for
The flow value ratio estimation formula includes a predetermined coefficient and an apparent shape factor based on an unburned component concentration in coal ash, an ash content in coal, and a surface area average particle size related to the particle size of coal ash, and The coefficient formed based on the unburned component concentration including a predetermined coefficient is determined by determining the coefficient in the undetermined flow value ratio estimation formula,
The flow value ratio estimating means is a surface area obtained from an actual measurement value of an unburned component concentration of coal ash to be evaluated, an ash content in coal obtained from the coal ash properties, and an actual measurement value of a particle size distribution of coal ash. The average particle size, or the estimated apparent shape factor and the actual measured value of the unburned component concentration are substituted into the corresponding item of the flow value ratio estimation formula, and the flow value ratio of the coal ash is estimated. An evaluation system for coal ash properties. In the coal ash property evaluation system according to any one of claims 10 to 12,
The estimation formula storage means further stores data of an activity index estimation formula for estimating the activity index of coal ash, and the calculation processing means estimates the activity index based on the activity index estimation formula Further comprising activity index estimation means for performing arithmetic processing for
The activity index estimation formula is based on the specific surface area of coal ash including a predetermined coefficient, the unburned component concentration in coal ash, and the content of the alkali component in coal ash. It is formed by determining the coefficient in the degree index estimation formula,
The activity index estimating means substitutes the estimated value or actual value of the specific surface area of the coal ash to be evaluated and the actual value of the unburned component concentration in the coal ash into the corresponding items of the activity index estimation formula. And estimating the activity index of the coal ash. In the coal ash property evaluation system according to any one of claims 10 to 13,
The density estimation formula is obtained by substituting the formulas (1) and (2) for determining the coefficients kd ₁ , kd ₂ , kd ₃ , and kd ₄ into the formula (3). Evaluation system.

In the coal ash property evaluation system according to any one of claims 11 to 13,
The specific surface area estimation formula is obtained by substituting the formulas (4) and (5) for determining the coefficients ks ₁ , ks ₂ , ks ₃ , and ks ₄ into the formula (6). Evaluation system for ash properties.

In the coal ash property evaluation system according to claim 12 or claim 13,
The flow value ratio estimation formula is obtained as a formula (7) in which coefficients kf ₁ , kf ₂ , and kf ₃ are determined.

In the evaluation system of the coal ash property according to claim 13,
The activity index estimation formula is obtained by substituting formula (8) into formula (9) and determining coefficients ka ₁ , ka ₂ , ka ₃ , ka ₄ . Evaluation system.

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