JP5916111B2 - Generation system and estimation method of estimation formula of grinding work index, and estimation system and estimation method of grinding power - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a system for generating an estimation formula for a pulverization work index and a generation method thereof, and a system for estimating a pulverization power and an estimation method thereof, and in particular, pulverized coal obtained by pulverizing subbituminous coal using a roller mill, and a mixed coal containing subbituminous coal and bituminous coal. It is useful when it is pulverized to obtain pulverized coal.

  In recent years, since the demand for bituminous coal is tight, it is important to secure fuel supply of pulverized coal fired power and to suppress an increase in fuel costs. Therefore, although the water content is high, the reserves are the second largest after bituminous coal, and the use of inexpensive subbituminous coal is being expanded.

  By the way, when newly introducing coal in the pulverized coal thermal power, the pulverization properties such as the power of the roller mill and the particle size of the pulverized coal are evaluated by the pulverization index HGI. Here, the grindability index HGI (Hardgrove Grindability Index) is an index for evaluating grindability, and is an analysis method in which a sample (coal) is dried and analyzed, and is defined in JIS M8801 (the same applies hereinafter). ).

  On the other hand, an evaluation method using a pulverization work index calculated from Bond's law is widely used for pulverization in a roller mill that pulverizes coal to produce pulverized coal. Here, the grinding work index calculated from Bond's law is an evaluation index proposed by the bond defined by the following formula, which is generally used in roller mills.

Milling work index = Roller mill power unit x (Average particle size of pulverized coal) ^1/2
FIG. 1 is a characteristic diagram in the case of examining the relationship between HGI and the grinding work index for each of subbituminous coal and bituminous coal, divided according to the presence or absence of adhering moisture. As shown in the figure, in subbituminous coal, HGI is the same as bituminous coal when the water content ratio (= moisture weight [kg] / weight of coal dried at 107 ° C. (JIS A1203); the same applies hereinafter) is low. It is shown in a substantially linear relationship with the grinding work index, and the grindability of the roller mill can be evaluated. On the other hand, when the water content ratio becomes high, the pulverization index becomes larger than that of coal with the same HGI, and it is not appropriate to use HGI for evaluation of pulverizability.

  By the way, when sub-bituminous coal having a high water content ratio is evaluated using HGI in the same manner as in the past, there are cases where predetermined grinding by a roller mill cannot be performed.

  For example, Patent Document 1 exists as a known document that discloses the point of adjusting the crushing force applied to coal using HGI as a parameter.

JP 2002-194408 A

  In view of the above prior art, the present invention accurately calculates the grinding work index even when pulverizing sub-bituminous coal having a high water content, or when mixing and pulverizing sub-bituminous coal and bituminous coal having a high water content. It is an object of the present invention to provide a system for generating an estimation formula of a grinding work index to be obtained and a method for generating the same, a system for estimating a grinding power, and a method for the estimation.

  The present invention that achieves the above object is based on the following knowledge. That is, sub-bituminous coal has a lot of moisture adhering to the coal surface in addition to the moisture contained in the coal. Adhesion moisture is given as a value obtained by subtracting the moisture content of coal on a constant humidity basis from the moisture content of coal on arrival basis (hereinafter the same).

  Here, when the relationship of the grinding work index to the moisture content of the adhered water was examined, the characteristics shown in FIG. 2 were obtained. The figure shows that when the water content ratio of the adhering water increases, the pulverization work index increases linearly regardless of subbituminous coal and bituminous coal. As a result, when the water content ratio of the moisture adhering to the coal increases, the coal to be pulverized between the roller and the table in the roller mill slips due to the presence of moisture, so that the rotation of the roller becomes slow. From this fact, it is considered that when the amount of adhering water is large, coal cannot be efficiently pulverized. In addition, it is estimated that the presence of such adhering moisture is one of the causes that the grindability of subbituminous coal cannot be evaluated by HGI.

  Using the pulverization index HGI so far, the point that the pulverization work index of the roller mill could not be evaluated was examined from the viewpoint of the moisture content of the adhering moisture. That is, the examination which paid attention to adhering moisture was performed about the grindability of coal using a roller mill. As a result, in the characteristic diagram shown in FIG. 2, it can be seen that the amount of increase in the pulverization work index is larger in the sub-bituminous coal than in the bituminous coal with respect to the moisture content of the adhered water. FIG. 3 shows a result of comparison between this increase ratio and coal grindability index HGI. As shown in the figure, in this case, it was found that the increase rate of the grinding work index decreases linearly with respect to HGI.

  The present invention proposes an estimation formula based on the characteristics shown in FIG. 3 in which the influence of adhering moisture on the pulverizability takes into account the influence that differs depending on the pulverizability index HGI.

The first aspect of the present invention based on such knowledge is as follows:
Ma data representing the moisture content ratio Ma adhering to the coal, HGI data representing the grindability index HGI, power W [W] of the roller mill for crushing the coal, and the amount of coal pulverization Q [ kg / h] and pulverized work index data representing the pulverized work index C calculated from Bond's law from the average particle diameter dp data of the pulverized coal conveyed from the roller mill to the furnace,
C = a × HGI + Ma × (b × HGI + c) + d (1)
Characterized in that it has an estimation formula generation calculating means for determining the coefficients a, b, c, d of the formula (1) expressed by the formula (1) and generating an estimation formula of the grinding work index C expressed by the formula (1). It is in the generation system of the estimation formula of the grinding work index.

The second aspect of the present invention is:
In the system for generating an estimation formula of the grinding work index described in the first aspect,
The estimation formula generation calculation means calculates coefficients a and d for the relational expression between the pulverization index HGI and the pulverization work index C by a least square method for coal without adhering moisture, Crushing is characterized in that the coefficients a, b, c and d are determined by calculating the coefficients b and c for the relational expression between the grindability index HGI and the grinding work index C by the least square method. It is in the generation system of the work index estimation formula.

The third aspect of the present invention is:
In the system for generating an estimation formula of the grinding work index described in the first aspect,
The estimation formula generation calculation means has at least four kinds of adhering moisture content ratio Ma, grindability index HGI and grind work index C.
C = a × HGI + Ma × (b × HGI + c) + d (1)
An equation having coefficients a, b, c, and d as unknowns is created by giving to the expression (1) expressed by the equation, and the coefficients a, b, c, and d are determined by solving the equations. It is in the generation system of the estimation formula of the grinding work index characterized by.

The fourth aspect of the present invention is:
An actual measurement process for actually measuring the moisture content ratio Ma and the grindability index HGI based on coal in the coal yard,
The power W [W] of the roller mill for pulverizing the coal, the coal pulverization amount Q [kg / h] measured by pulverizing with the roller mill, and the measured average particle diameter dp of the pulverized coal conveyed toward the furnace from the roller mill Pulverization work index calculating step of calculating the pulverization work index C calculated from Bond's law,
The adhering moisture content ratio Ma, grindability index HGI and grind work index C are as follows:
C = a × HGI + Ma × (b × HGI + c) + d (1)
An equation generating step for determining the coefficients a, b, c, d by generating the equation for the grinding work index C expressed by the equation (1) by giving the equation (1) expressed by This is a method for generating an estimation formula for a grinding work index.

According to a fifth aspect of the present invention,
In the method for generating an estimation formula for the grinding work index described in the fourth aspect,
In the estimation formula generating step, the coefficients a and d are calculated for the relational expression between the grindability index HGI and the grinding work index C by the least square method for coal without adhering moisture, and the coal with adhering moisture is targeted. The calculation of the grinding work index is characterized in that the coefficients a, b, c, d are determined by calculating the coefficients b, c for the relational expression between the grindability index HGI and the grinding work index C by the least square method. There is an expression generation method.

The sixth aspect of the present invention is:
In the method for generating an estimation formula for the grinding work index described in the fourth aspect,
In the estimation formula generation step, at least four kinds of adhering water content ratio Ma, grindability index HGI, and grind work index C are obtained.
C = a × HGI + Ma × (b × HGI + c) + d (1)
An equation having coefficients a, b, c, and d as unknowns is created by giving to equation (1) expressed by the following equation, and the coefficients a, b, c, and d are determined by solving the equations: There is a method for generating the estimation formula of the grinding work index.

The seventh aspect of the present invention is
Input data generation means for outputting Ma data representing the moisture content ratio Ma of the moisture content of the new coal to be crushed by the roller mill and HGI data representing the grindability index HGI;
Substituting the Ma data and HGI data relating to the new coal into the estimation formula of the grinding work index generated by the generating system according to any one of the first to third aspects based on past data. A pulverization work index estimating means for calculating an estimated value _CE of the pulverization work index of the new coal,
Pulverized condition setting means and data representing the setting value dp _S of the particle size of the data and the average representative of the set value Q _S grinding a target amount of the pulverized coal is set,
Based on the data representing the setting value dp _S of the data representing the estimated value C _E, data and the particle diameter represents the setting value Q _S of the crushing amount set in the grinding condition setting unit, W _{E =} C E × Q lies estimation system grinding power, characterized in that it comprises a power estimation means for calculating the estimated value W _E of the power W required at the time of grinding by _{S / √dp S.}

The eighth aspect of the present invention is
In the pulverization power estimation system described in the seventh aspect,
While the input data generation means outputs the mixed coal data representing the mixed coal ratio together with each Ma data and HGI data regarding a plurality of types of coal,
In the past data of the plurality of types of coal, the pulverization work index estimating means uses the estimation formula generation system described in any one of the first to third aspects based on the past data of the plurality of types of coal. Taking into account the coal blend data representing the coal blend ratio of the plurality of types of coal, the new formula is used to calculate the pulverization work index generated by weighted averaging the values at the time of individual pulverization of each coal type according to the coal blend ratio. In addition to substituting Ma data and HGI data for coal, the value of the new coal at the time of single pulverization of each coal type is weighted and averaged according to the coal blend ratio of the new coal, and an estimated value C of the pulverization work index of the new coal _The pulverization power estimation system is characterized in that _E is calculated.

The ninth aspect of the present invention provides
In the pulverization power estimation system described in the seventh or eighth aspect,
An upper limit calculation means for calculating an upper limit C _Limit of the grinding work index, which is an acceptance limit of a roller mill for pulverizing coal;
Data representing the estimated value _CE calculated by the grinding work index calculating means is compared with data representing the upper limit value C _Limit calculated by the upper limit calculating means, and the power estimation is performed only when C _E <C _Limit. The pulverization power estimation system has a determination means for calculating the estimated power in the means.

The tenth aspect of the present invention provides
An actual measurement step of actually measuring the adhering water content ratio Ma and the grindability index HGI for the new coal to be crushed by a roller mill;
Estimating formula of grinding work index generated by the generation method described in any one of the fourth to sixth aspects based on past data based on the moisture content ratio Ma and the grindability index HGI relating to the new coal , A pulverization work index estimation step of calculating an estimated value _CE of the pulverization work index of the new coal by substituting the moisture content ratio Ma and the pulverization index HGI for the new coal,
The upper limit value C _Limit of the pulverization work index that becomes the acceptance limit of the roller mill is the power of the roller mill, the coal pulverization amount measured by pulverization by the roller mill, and the measured average of pulverized coal conveyed from the roller mill to the furnace. Based on the particle size, an upper limit calculation step calculated from Bond's law;
A back-calculation step of back-calculating the moisture content ratio Ma _Limit of coal, which becomes the acceptance limit of the roller mill, based on the HGI actually measured in the measurement step and the upper limit C _Limit calculated in the upper limit calculation step;
A comparison step of comparing the estimated value _CE and the upper limit value C _Limit ;
When the comparison result in the comparison step is not C _E <C _Limit , drying is performed so that the adhered water content ratio Ma becomes equal to or less than the adhered water content ratio Ma _{Limit that} can be pulverized, and the process is returned to the actual measurement process after predetermined drying. A drying process;
A pulverization condition setting step for setting a target pulverization amount and average particle size of pulverized coal;
When the comparison result in the comparison step is C _E <C _Limit , it is assumed that there is no problem in coal pulverization, and the pulverization amount setting value Qs and the average particle size setting value set in the pulverization condition setting step based on dps and the estimated value C _E, the estimation method of grinding power, characterized in that it comprises a grinding power estimation step of calculating the power W required by W = C × Q / √dp during grinding of the new coal is there.

  According to the present invention, the influence of the adhering moisture on the pulverization of coal is estimated based on the knowledge that the pulverization index HGI is low and becomes large in coal that is difficult to pulverize, and the pulverization work index C is estimated in consideration of this influence. Therefore, the grinding work index C can be estimated with high accuracy. FIG. 4 shows the comparison result between the measured value of the grinding work index C on the horizontal axis and the estimated value of the grinding work index C estimated by the estimation method according to the present invention on the vertical axis. This figure evaluates the actual pulverization work function by adding the amount corresponding to the moisture content of the adhering water to the subbituminous coal using the estimation formula of the pulverization work index generated by the present invention. It shows that it is possible to do.

  Further, the pulverization power in the newly introduced coal roller mill can be estimated with high accuracy using the estimation formula of the pulverization work index estimated as described above. As a result, for example, the proportion of the electric power accompanying the pulverization power in the in-house electric power in the power generation facility can be accurately grasped.

  Further, by performing processing such as comparing the estimated value of the pulverization work index with the upper limit value of the pulverization work index, it is possible to easily determine whether or not pulverization is possible with a roller mill.

It is a characteristic view which shows the relationship between HGI and grinding work index in subbituminous coal and bituminous coal. It is a characteristic view which shows the relationship of the grinding | pulverization work index | exponent with respect to the moisture content of adhesion regarding several charcoal types. It is a characteristic view which shows the increase rate of a grinding | pulverization work index | exponent, and the relationship of HGI. It is a characteristic view which shows the comparison result of the actual value of a grinding work index, and the estimated value of the grinding work index estimated with the estimation method by this invention. It is a block diagram which shows the production | generation system of the estimation formula of the grinding work index which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the estimation system of the grinding | pulverization power which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the estimation procedure in the estimation system of the pulverization power shown in FIG. It is a block diagram which shows the estimation system of the grinding | pulverization power which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the estimation procedure in the estimation system of the grinding power shown in FIG. It is a block diagram which shows the estimation system of the grinding | pulverization power which concerns on the 4th Embodiment of this invention. It is a characteristic view relevant to the knowledge used as the foundation of the 4th embodiment of the present invention, and is a characteristic view showing the characteristic of the grinding work index at the time of subbituminous coal mixture. It is a characteristic view relevant to the knowledge used as the foundation of the 4th embodiment of the present invention, and is a characteristic figure showing a comparison result of an estimation result of a crushing work index at the time of subbituminous coal mixture, and an experimental result.

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

<First Embodiment>
FIG. 5 is a block diagram showing a system for generating an estimation formula for a grinding work index according to the first embodiment of the present invention. As shown in the figure, the coal stored in the coal storage yard 1 is pulverized by a roller mill 2 to be pulverized coal having a predetermined average particle diameter and conveyed / supplied to the furnace 3 of the boiler.

In this embodiment, as the data of coal to be crushed, the moisture content Ma. r and a moisture content Ma. d and the grindability index HGI are actually measured by the coal data measurement unit 4. Here, the moisture contained in the coal is present in two forms: “attached moisture” present on the surface of the particles and “moisture in the pores” present in the particles. About the relationship of these water content ratios, it represents like following Formula (2).
Total moisture content = moisture content in the pores + adhesion moisture content (2)

  In the present invention, the moisture of the sample dried at 107 ° C. for 1 hour is defined as the moisture content of the pore water, and the coal raw material before pulverization is defined. The difference between the moisture content of charcoal and the moisture content of the constant humidity base is defined as the moisture content of the attached moisture.

  Bituminous coal has a low moisture content in the pores and a higher moisture content in the adhered moisture, while subbituminous coal has a high moisture content in the pores as well as the moisture content in the pores. Therefore, when measuring HGI, which is an index for evaluating grindability, a sample that does not contain adhering moisture is used.

  The grindability index HGI is measured by the method defined in JIS M8801.

  The roller mill data section 5 stores data representing the power W of the roller mill 2 and data of actual measurement values of the coal pulverization amount Q pulverized by the roller mill 2. The pulverized coal data section 6 stores data representing the average value of the particle diameters dp of the pulverized coal crushed by the roller mill 2 and measured.

The water content calculation unit 7 is an arrival-based water content Ma. r and a moisture content Ma. Based on d, the moisture content ratio Ma of the attached water is calculated based on the following equation (3), and Ma data D1 representing this is generated.
Ma = Ma. r-Ma. d (3)

  The HGI data generation unit 8 generates HGI data D2 based on the HGI actually measured by the coal data actual measurement unit 4.

In the pulverization work index calculation unit 9, the data representing the power W stored in the roller mill data unit 5, the data of the measured value of the coal pulverization amount Q, and the particle size dp of the pulverized coal measured by pulverizing with the roller mill 2 are measured. Based on the data representing the average value, the grinding work index C is calculated by the following equation (4) using Bond's law.
C = (W / Q) × √dp (4)

  As a result, the grinding work index calculation unit 9 generates grinding work index data D3 representing the grinding work index C.

  The estimation formula generation calculation unit 10 is based on Ma data D1 representing the moisture content ratio Ma in the coal, HGI data D2 representing the grindability index HGI, and grinding work index data D3 representing the grinding work index C. Determine the unknown coefficients a, b, c, d of 1). As a result, an estimation formula of the grinding work index C that is a function of HGI and Ma is generated.

  Here, the estimation formula generation calculation unit 10 in the present embodiment calculates the coefficients a and d for the relational expression between the pulverization index HGI and the pulverization work index C by the least square method for coal without adhering moisture, The coefficients a, b, c, and d are determined by calculating the coefficients b and c for the relational expression between the grindability index HGI and the grinding work index C by the least square method for coal containing moisture. “Coal without adhering moisture” means coal whose total moisture content and moisture content in the pores are almost the same and the surface is not wet. “Coal with adhering moisture” means the total moisture content of coal. And the amount of moisture in the pores is different and the surface is wet.

  By actually measuring the HGI and Ma of the specific coal and substituting the values into the estimation formula of the pulverization work index C generated according to this embodiment, the pulverization work index C required when pulverizing the specific coal is calculated. Can be calculated.

<Second Embodiment>
FIG. 6 is a block diagram showing a pulverization power estimation system according to the second embodiment of the present invention. This embodiment is a system for estimating the pulverization power of new coal using the estimation formula of the pulverization work index C generated according to the first embodiment.

  In the pulverization work index estimation unit 20 in the present embodiment, for example, the pulverization work index generated by the estimation formula generation system according to the first embodiment based on parameters extracted from past data of coal used in the power plant. C estimation formula is stored. This estimation formula is based on Ma data D1, HGI data D2, and pulverization work index data D3 representing the pulverization work index C based on past data of coal actually measured by the coal data measurement unit 4. Are generated by determining the coefficients a, b, c, and d. Here, the pulverization work index data D3 is based on data representing the power W of the roller mill 2, data representing the actually measured coal pulverization amount Q, and data representing the average particle diameter dp of the pulverized coal actually measured after pulverization by the roller mill 2. It is generated by performing the calculation shown in (4).

  The input data generation unit 11 generates Ma data D11 representing the moisture content of the adhering moisture of the new coal to be crushed by the roller mill 2 and HGI data D12 representing the grindability index HGI. In other words, the moisture content calculation unit 17 performs the arrival-based moisture content Ma. r and a moisture content Ma. Based on d, the moisture content ratio Ma of the adhering moisture is calculated based on the above equation (3) for new coal, and Ma data D11 representing this is generated. Further, the HGI data generation unit 18 generates HGI data D12 based on the new coal pulverization index HGI actually measured by the coal data measurement unit 14.

The grinding work index estimation unit 20 substitutes the Ma data D11 and HGI data sent from the input data generation unit 11 into the estimation formula of the grinding work index C generated by the estimation formula generation system according to the first embodiment. Then, an estimated value _CE of the pulverization work index C of the new coal to be pulverized is calculated.

On the other hand, the pulverization condition setting unit 12 includes a pulverization amount setting unit 15 and a particle size setting unit 16. The crushing amount setting unit 15, is set data on grinding amount set value Q _S representing the grinding rate Q of pulverized coal ground in a roller mill 2. Further, in the particle size setting unit 16, data relating to the particle size setting value dp _S representing the average particle size dp of the pulverized coal pulverized by the roller mill 2 is set.

Power estimation section 13, estimated value C data D13 representing the _E, data D14 and grain axis length set value representing the grinding amount set value Q _S set in the grinding condition setting unit 12 dp _S supplied from the grinding work index estimation unit 20 based on the data D15 indicating the _calculated the estimated power _{W E} when grinding the new coal predetermined amount, a predetermined particle size using a W _E = _C E × relational expression _{Q S} / _{√dp S.}

FIG. 7 is a flowchart showing an estimation procedure in the pulverization power estimation system according to this embodiment. As shown in the figure, first, in an actual measurement step 21, the water content ratio of adhering moisture and the pulverizability index HGI of new coal to be pulverized by the roller mill 2 are actually measured. Next, in the pulverization work index estimation step 22, the estimated value C of the pulverization work index C is substituted by substituting the measured water content ratio and HGI data into the pulverization index estimation formula separately generated based on the past coal data. _E is calculated. Based on the estimated value _CE , the set value Q _S of the pulverization amount Q set in the pulverization condition setting step 23, and the set value dp _S of the average particle size dp, a new predetermined amount of coal is calculated in the power estimation step 24. The power of the roller mill 2 required for pulverizing into pulverized coal with a predetermined particle diameter is estimated.

According to this embodiment, the new coal specified by the Ma data D11 and the HGI data D12 is pulverized under the pulverization conditions set in the pulverization condition setting unit 12 under the pulverization conditions set in the pulverization condition setting unit 12. the estimated power W _E can be accurately calculated. Such estimated power W _E, for example power accompanying the estimated power W _E is a useful indicator applied when grasping the ratio in the auxiliary power in the power generation equipment.

<Third Embodiment>
FIG. 8 is a block diagram showing a pulverization power estimation system according to the third embodiment of the present invention. In the present embodiment, a function for determining whether or not coal is pulverizable by adding the pulverization capability of the roller mill 2 to the pulverization power estimation system according to the second embodiment shown in FIG. 6 is added. Therefore, the same parts as those in the pulverization power estimation system according to the second embodiment shown in FIG.

As shown in FIG. 8, the pulverization power estimation system according to this embodiment includes a determination unit 31 and upper limit calculation units 32 and 33. Here, the determination unit 31 compares the estimated value _CE estimated by the grinding work index estimation unit 20 with the upper limit value C _Limit of the grinding work index of the roller mill 2 stored in the upper limit calculation unit 32. As a result, on the condition that C _E <C _Limit is satisfied, the power estimation unit 13 estimates the estimated power when pulverizing new coal under the pulverization conditions set in the pulverization condition setting unit 12. This is because when C _E <C _Limit is satisfied (in the case of Yes), it is estimated that it is within the range of the crushing ability of the roller mill 2. Here, the upper limit calculator 32 calculates the upper limit C _Limit (= (W / Q) × √dp) of the grinding work index from the past operation results of the roller mill and stores the data.

On the other hand, when C _E <C _Limit is not satisfied (in the case of No), it is determined that the pulverization capacity of the roller mill 2 has been exceeded and that the coal needs to be further dried, and the coal is turned to the drying yard 34.

The upper limit calculator 33 is based on the HGI data D12 stored in the HGI data generator 18 and the upper limit data D16 representing the upper limit C _Limit of the grinding work index C. The upper limit value Ma _Limit of the water content ratio Ma is calculated backward.

Ma _Limit = (C _Limit −aHGI−d) / (bHGI + c) (5)

The upper limit value Ma _Limit calculated by the above equation (5) is an indicator of the water content ratio Ma of the coal in the drying yard 34. Therefore, after drying until Ma <Ma _Limit , the input data generating unit 11 collects again actual measurement data of new coal to be crushed.

FIG. 9 is a flowchart showing an estimation procedure in the pulverization power estimation system according to this embodiment. As shown in FIG. 9, in FIG. 9, several steps are added to the flowchart shown in FIG. 7 due to the addition of a comparison step for comparing the estimated value _CE and the upper limit value C _Limit . Therefore, in FIG. 9, the same parts as those in FIG.

As shown in FIG. 9, when the upper limit C _Limit calculated in the upper limit calculation step 35 and the estimated value _CE are compared in the comparison step 36, and C _E <C _Limit is satisfied (in the case of Yes) In addition, it is estimated that there is no problem at the time of coal pulverization by the roller mill 2, and the power of the roller mill 2 required to pulverize a predetermined amount of new coal into pulverized coal having a predetermined particle diameter is estimated in the power estimation step 24. To do.

On the other hand, when C _E <C _Limit is not satisfied (in the case of No), it is necessary to dry the coal so that the moisture content Ma of the coal is further reduced. The drying step 39 is performed until the water content ratio Ma becomes equal to or lower than the upper limit value Ma _Limit . Thereafter, the measurement process 21 is again performed. Here, the upper limit value Ma _Limit is inversely calculated based on the equation (5) in the upper limit value calculation step 38 based on the HGI data D12 and the upper limit value data D16, and given as a result.

According to this embodiment, in consideration of the crushing capacity of the roller mill 2, the grinding conditions set only the grinding condition setting unit 12 coal is within a range of grinding ability, accurately calculate the estimated power W _E when grinding can do. On the other hand, when it exceeds the crushing capacity, it can be processed so as to be within the range of the crushing capacity by drying until the water content ratio Ma becomes the upper limit value Ma _Limit or less.

<Fourth embodiment>
FIG. 10 is a block diagram showing a crushing power estimation system according to the fourth embodiment of the present invention. This embodiment is a case where a plurality of different coal types are mixed and pulverized, such as a mixture of bituminous coal and subbituminous coal, but the basic system configuration is the same as that of the second embodiment shown in FIG. It is. Therefore, the same parts as those in FIG.

  Since sub-bituminous coal has a high water content and is difficult to grind, when using it in an actual power plant, mixed coal operation with bituminous coal is preferable. This form is applied when subbituminous coal is mixed with bituminous coal.

Therefore, in this embodiment, first, the blending rate of different types of coal is taken into consideration when generating the calculation formula for the grinding work index. Specifically, it has coal data measurement sections 4A and 4B relating to coals A and B of different coal types, respectively, and is the same as that of the first embodiment based on past data measured for each coal type. In this manner, Ma data D1 _A and D1 _B and HGI data D2 _A and D2 _B relating to coals A and _B are obtained. In this embodiment, may be set to data of CCS, the imported coal is blended ratio of each coal type in CCS, the imported coal is blended rate setting unit 41, Ma data _{D1 A,} D1 B, HGI data _D2 A, D2 _B and ground work index data representing a grinding work index C Based on D3, the unknown coefficients a, b, c, and d in equation (1) are used based on the physical properties of coals A and B used in the power plant so far, the grinding conditions of roller mill 2 and the particle size of pulverized coal. And decide. At this time, by calculating the weighted average of the data in accordance with the coal mixture rate, an estimation formula for the pulverization power taking into account the coal mixture rate of different coal types is generated. Data related to the estimation formula is stored in the grinding work index estimation unit 40.

On the other hand, the input data generation units 11A and 11B in the present embodiment, together with the Ma data D11 _A and D11 _B and the HGI data D12 _A and D12 _B for each coal for each new coal A and B of the coal type, the coal mixture rate setting unit 42 Is supplied to the pulverization work index estimation unit 40 together with the blend data representing the blend ratio Rn. The input data generation unit 11A is, has a HGI data generating unit 18A for generating a new coal A generates each Ma data D11 _A relates to water content ratio calculation unit 17A and the HGI data D12 _A, the input data generating unit 11B has a water content ratio calculation unit 17B that generates each Ma data D11 _B related to the new coal A, and an HGI data generation unit 18B that generates the HGI data D12 _B. The water content calculation units 17A, 17B are the arrival-based water content ratio Ma. Before pulverization measured by the coal data measurement units 14A, 14B. r and a moisture content Ma. Based on d, the moisture content ratios Ma _A and Ma _B of the adhering water are calculated based on the formula (3) for the new coals A and B, respectively, as in the second embodiment, and Ma data D11 _A and D11 representing these are calculated. _B is generated. Further, the HGI data generation units 18A and 18B generate HGI data D12 _A and D12 _B based on the grindability index HGI of new new coals A and B measured by the coal data measurement units 14A and 14B, respectively.

In the pulverization work index estimation unit 40, the estimated value C _BE of the pulverization work index C _{Bld in} this case is estimated by a weighted average using the following equation (6), taking into account the blend ratio Rn.

Grinding work index C _Bld = Σ [Rn × (a × HGI _n + d)] +
_{Σ [Rn × {Ma n ×} (b × HGI n + c)}] ···· (6)

On the other hand, the power estimation unit 13 is the estimated value C data D20 representing the _BE, data D14 and grain axis length set value representing the grinding amount set value Q _S set in the grinding condition setting unit 12 supplied from the milling Work Index estimation unit 40 Based on the data D15 representing dp _S , the estimated power W in the case of pulverizing a new amount of different types of coal blended using a relational expression of W _E = C _E × Q _S / √dp _S into a predetermined amount and a predetermined particle size _E is calculated.

According to the present embodiment, the estimated power W _E when grinding the heterogeneous coal Through CCS, the imported coal is blended, it is possible to accurately calculate in consideration of CCS, the imported coal is blended rate.

  Here, the knowledge that is the basis of this embodiment will be described.

  Since sub-bituminous coal has a high water content and is difficult to grind, when using it at an actual power plant, mixed coal operation with bituminous coal is carried out. In this section, we evaluated the grinding characteristics when sub-bituminous coal was mixed with bituminous coal.

  Here, the bituminous coal before pulverization was in a dry state without adhering moisture. On the other hand, sub-bituminous coal is dried in the same manner as bituminous coal and is wetted so that only moisture in the pores is present, and moisture is added, so that the moisture content of adhering moisture becomes 0.15 which is equivalent to that at the time of arrival. The comparison was made in two forms including not only the moisture in the pores but also the adhering moisture.

  Fig. 11 shows the grinding work index when sub-bituminous coal is mixed. As shown in the figure, regardless of the presence or absence of moisture adhering to both bituminous coal and subbituminous coal, the grinding work index is almost the same as the weighted average of the values at the time of simple grinding for each coal type according to the coal mixture ratio of subbituminous coal. It was found to show an equivalent value.

  In this embodiment, as for the estimation method at the time of coal blending, 1) a method of calculating from the apparent coal properties of the fuel mixed with two types of coal, and 2) weighting the result of each coal type simple grinding according to the coal blending rate Two types of calculation methods can be considered on average. FIG. 12 shows the results of comparing the estimated values calculated from these methods with the experimental results. Referring to FIG. 12, when the two coal types do not contain adhering moisture, it can be seen that the estimated values are both the same and are in good agreement with the experimental results.

  On the other hand, when sub-bituminous coal contains a lot of adhering moisture, 1) the results estimated from the apparent coal properties of the mixed fuel are 2) lower than the results estimated from the results of each coal type plain grinding. It can be seen that the difference from the experimental results becomes large. This is because the increase in the grinding work index due to adhering water in the apparent HGI of the mixed coal is reduced. From these results, it was found that the estimation method in which the results of the simple pulverization of each coal type in 2) are weighted averaged according to the blending ratio can simulate actual pulverization well.

  From this, when new subbituminous coal is introduced and operated under conditions of blending with bituminous coal, the estimation system shown in FIG. 12 is constructed, and the pulverization power at the time of blending is well estimated by the predetermined treatment as described above in each part. It is considered possible.

<Other embodiments>
The present invention is not limited to the above embodiment. For example, in the above embodiment, the least square method is used when forming the estimation formula of the grinding work index C. However, the present invention is not limited to this, and a quaternary linear equation having coefficients a, b, c, and d as unknowns is created. The coefficients a, b, c, and d may be determined as the solution. In other words, at least four types of moisture content ratio Ma, grindability index HGI and grind work index C are given to the above equation (1) to create an equation with coefficients a, b, c, d as unknowns, In principle, it is also possible to determine the coefficients a, b, c and d by solving the equations.

Moreover, although 4th Embodiment was demonstrated based on FIG. 10 as an estimation system of the pulverization power at the time of mixed coal, the determination part 31 and upper limit calculation part which were demonstrated by 3rd Embodiment in 4th Embodiment. This does not prevent the system from combining 32 and 33. When combined, the estimated value C _BE estimated by the pulverization work index estimation unit 40 in the fourth embodiment is compared with the pulverization work index upper limit C _Limit of the roller mill 2 so that the condition of C _BE <C _Limit is satisfied. If the condition is established, it can be determined that the pulverization is possible, and if not, it can be determined how much the coal can be pulverized by comparing with the upper limit value Ma _Limit of the water content ratio. In this case, the upper limit values C _Limit and Ma _Limit are generated as values in consideration of the mixture ratio Rn.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used in industrial fields such as the electric power industry that generates power using pulverized coal as fuel.

DESCRIPTION OF SYMBOLS 1 Coal storage place 2 Roller mill 3 Furnace 4 Coal data measurement part 5 Roller mill data part 6 Pulverized coal data part 7 Moisture content calculation part 8 HGI data generation part 9 Grinding work index calculation part 10 Estimation formula generation calculation part 11 Input data generation part 12 Grinding Condition setting unit 13 Power estimation unit 14 Coal data actual measurement unit 15 Grinding amount setting unit 16 Particle size setting unit 17 Water content ratio calculation unit 18 Data generation unit 20 Grinding work index estimation unit 21 Actual measurement process 22 Grinding work index estimation process 23 Grinding condition setting Process
24 Power estimation process

Claims (10)

Ma data representing the moisture content ratio Ma adhering to the coal, HGI data representing the grindability index HGI, power W [W] of the roller mill for crushing the coal, and the amount of coal pulverization Q [ kg / h] and pulverized work index data representing the pulverized work index C calculated from Bond's law from the average particle diameter dp data of the pulverized coal conveyed from the roller mill to the furnace,
C = a × HGI + Ma × (b × HGI + c) + d (1)
Characterized in that it has an estimation formula generation calculating means for determining the coefficients a, b, c, d of the formula (1) expressed by the formula (1) and generating an estimation formula of the grinding work index C expressed by the formula (1). A system for generating a formula for calculating the grinding work index. In the generation system of the estimation formula of the grinding work index according to claim 1,
The estimation formula generation calculation means calculates coefficients a and d for the relational expression between the pulverization index HGI and the pulverization work index C by a least square method for coal without adhering moisture, Crushing is characterized in that the coefficients a, b, c and d are determined by calculating the coefficients b and c for the relational expression between the grindability index HGI and the grinding work index C by the least square method. Generation system for work index estimation formula. In the generation system of the estimation formula of the grinding work index according to claim 1,
The estimation formula generation calculation means has at least four kinds of adhering moisture content ratio Ma, grindability index HGI and grind work index C.
C = a × HGI + Ma × (b × HGI + c) + d (1)
An equation having coefficients a, b, c, and d as unknowns is created by giving to the expression (1) expressed by the equation, and the coefficients a, b, c, and d are determined by solving the equations. A system for generating a formula for estimating the grinding work index. An actual measurement process for actually measuring the moisture content ratio Ma and the grindability index HGI based on coal in the coal yard,
The power W [W] of the roller mill for pulverizing the coal, the coal pulverization amount Q [kg / h] measured by pulverizing with the roller mill, and the measured average particle diameter dp of the pulverized coal conveyed toward the furnace from the roller mill Pulverization work index calculating step of calculating the pulverization work index C calculated from Bond's law,
The adhering moisture content ratio Ma, grindability index HGI and grind work index C are as follows:
C = a × HGI + Ma × (b × HGI + c) + d (1)
An equation generating step for determining the coefficients a, b, c, d by generating the equation for the grinding work index C expressed by the equation (1) by giving the equation (1) expressed by A method for generating an estimation formula for a grinding work index. In the generation method of the calculation formula of the grinding work index according to claim 4,
In the estimation formula generating step, the coefficients a and d are calculated for the relational expression between the grindability index HGI and the grinding work index C by the least square method for coal without adhering moisture, and the coal with adhering moisture is targeted. The calculation of the grinding work index is characterized in that the coefficients a, b, c, d are determined by calculating the coefficients b, c for the relational expression between the grindability index HGI and the grinding work index C by the least square method. Expression generation method. In the generation method of the calculation formula of the grinding work index according to claim 4,
In the estimation formula generation step, at least four kinds of adhering water content ratio Ma, grindability index HGI, and grind work index C are obtained.
C = a × HGI + Ma × (b × HGI + c) + d (1)
An equation having coefficients a, b, c, and d as unknowns is created by giving to equation (1) expressed by the following equation, and the coefficients a, b, c, and d are determined by solving the equations: To generate a formula for calculating the grinding work index. Input data generation means for outputting Ma data representing the moisture content ratio Ma of the moisture content of the new coal to be crushed by the roller mill and HGI data representing the grindability index HGI;
A new one is obtained by substituting the Ma data and the HGI data for the new coal into the estimation formula of the grinding work index generated by the generating system according to any one of claims 1 to 3 based on past data. A grinding work index estimating means for calculating an estimated value _CE of the grinding work index of coal;
Pulverized condition setting means and data representing the setting value dp _S of the particle size of the data and the average representative of the set value Q _S grinding a target amount of the pulverized coal is set,
Based on the data representing the setting value dp _S of the data representing the estimated value C _E, data and the particle diameter represents the setting value Q _S of the crushing amount set in the grinding condition setting unit, W _{E =} C E × Q _S
Power estimation means for calculating an estimated value W _E of power W required for grinding by / √dp _S. In the grinding power estimation system according to claim 7,
While the input data generation means outputs the mixed coal data representing the mixed coal ratio together with each Ma data and HGI data regarding a plurality of types of coal,
The said pulverization work index estimation means is based on the past data of a plurality of types of coal, and the plurality of the past data of the plurality of types of coal in the past data of the estimation formula generation system according to any one of claims 1 to 3. In consideration of the blended coal data representing the coal blending rate of the various types of coal, the estimated value of the pulverization work index generated by weighted averaging the values at the time of individual pulverization of each coal type according to the blended coal rate is related to the new coal Substituting Ma data and HGI data, and calculating a weighted average of the values at the time of single pulverization of each coal type of the new coal according to the coal blend ratio of the new coal, and calculating an estimated value _CE of the new coal pulverization work index An estimation system for pulverization power characterized by being operated. In the estimation system of the grinding power according to claim 7 or claim 8,
An upper limit calculation means for calculating an upper limit C _Limit of the grinding work index, which is an acceptance limit of a roller mill for pulverizing coal;
Data representing the estimated value _CE calculated by the grinding work index calculating means is compared with data representing the upper limit value C _Limit calculated by the upper limit calculating means, and the power estimation is performed only when C _E <C _Limit. A pulverization power estimation system, comprising: a determination means for calculating the estimated power in the means. An actual measurement step of actually measuring the adhering water content ratio Ma and the grindability index HGI for the new coal to be crushed by a roller mill;
Based on the moisture content ratio Ma and the grindability index HGI related to the new coal, based on past data, an estimation formula for the milling work index generated by the generating method according to any one of claims 4 to 6, A pulverization work index estimation step of calculating an estimated value _CE of the pulverization work index of the new coal by substituting the moisture content ratio Ma and the friability index HGI for the new coal;
The upper limit value C _Limit of the pulverization work index that becomes the acceptance limit of the roller mill is the power of the roller mill, the coal pulverization amount measured by pulverization by the roller mill, and the measured average of pulverized coal conveyed from the roller mill to the furnace. Based on the particle size, an upper limit calculation step calculated from Bond's law;
A back-calculation step of back-calculating the moisture content ratio Ma _Limit of coal, which becomes the acceptance limit of the roller mill, based on the HGI actually measured in the measurement step and the upper limit C _Limit calculated in the upper limit calculation step;
A comparison step of comparing the estimated value _CE and the upper limit value C _Limit ;
When the comparison result in the comparison step is not C _E <C _Limit , drying is performed so that the adhered water content ratio Ma becomes equal to or less than the adhered water content ratio Ma _{Limit that} can be pulverized, and the process is returned to the actual measurement process after predetermined drying. A drying process;
A pulverization condition setting step for setting a target pulverization amount and average particle size of pulverized coal;
When the comparison result in the comparison step is C _E <C _Limit , it is assumed that there is no problem in coal pulverization, and the pulverization amount setting value Qs and the average particle size setting value set in the pulverization condition setting step based on dps and the estimated value _{C E, W = C × Q} / √dp by estimating how grinding power and having a grinding power estimation step of calculating the power W required at the time of pulverization of the new coal.