JP5062679B2 - Simulation method, program, recording medium recording the same, and simulation apparatus - Google Patents

Description

  The present invention relates to a simulation method, a program, a recording medium recording the same, and a simulation apparatus, and more particularly to a simulation method, a program, a recording medium recording the same, and a simulation apparatus for pulverized coal combustion.

  CFD (Computational Fluid Dynamics) simulation technology using general-purpose thermal fluid analysis software is used for design and phenomenon analysis in various industrial fields. In pulverized coal combustion in coal-fired power generation, which has been attracting attention in recent years, the behavior of pulverized coal particles in the vicinity of the burner of the furnace is being analyzed by CFD simulation.

  Here, pulverized coal combustion will be described with reference to FIG. As shown to Fig.1 (a), pulverized coal consists of a water | moisture content, ash content, fixed carbon, and a volatile content, and these ratios are estimated beforehand by industrial analysis. When this pulverized coal is put into a furnace and heated, moisture is released, and then volatile components are released by thermal decomposition. Most of the pulverized coal after the volatile matter is released becomes char composed of fixed carbon and ash. The fixed carbon contained in the char that has left the furnace without being burned is unburned in ash.

  Among the components of pulverized coal, the volatile matter has a great influence on the flame shape and the behavior of pulverized coal particles in the vicinity of the furnace burner. Varies greatly depending on the temperature rate. For example, when the temperature rising rate shown in FIG. 1B is large, the amount of volatile matter actually released becomes larger than the amount of volatile matter released by industrial analysis performed at a low temperature rising rate.

Conventionally, in such a simulation of pulverized coal combustion, it is known that modeling is performed on the assumption that a volatile component is a pseudo component CH _x O _y (see, for example, Patent Document 1). For example, if the C: H: O ratio (element composition ratio) in the volatile component is n: m: l, the component of the volatile component is assumed to be nCH _{m / n} O _{1 / n} . In the volatile matter thus assumed, the amount of volatile matter actually released is assumed to be constant as a value obtained by multiplying the industrial analysis value by a constant (1.2 to 1.5), It did not take into account changes in the total amount of volatile matter released and the rate of release due to differences in the heating rate.

JP 2002-356682 A (Claim 1, paragraph 0021)

  By the way, in the simulation of pulverized coal combustion, the transport equation is solved for each component in the volatile matter. In such a pulverized coal combustion simulation, a simulation that is closer to reality is performed with regard to the temperature, taking into account changes in the total amount of volatile matter released and the release rate due to the difference in the temperature rise rate of particles that was not considered in the conventional simulation If you try to do this, the following problems occur.

That is, the conventional pseudo component of volatiles CH _x O _y as, or C _x H _y O _z with assuming, every time a change in amount of released volatiles due to the difference in heating rate of the particles, in other words the volatile Each time a different element composition ratio (C: H: O = x: y: z) is given to the pseudo component of the minute, the transport equation concerning the volatile component is solved, and a huge number of transport equations are obtained. In order to solve, the problem that calculation time increases significantly arises.

  Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a simulation method and a simulation apparatus for pulverized coal combustion that have a small calculation load and are more realistic in terms of temperature. Another object of the present invention is to provide a program for executing this simulation method and a recording medium on which the program is recorded.

  The method for simulating pulverized coal combustion according to the present invention includes a first component, a second component having a molecular formula different from that of the first component, and a volatile matter released by pyrolyzing the particles of the pulverized coal. And pulverized coal combustion for simulating pulverized coal combustion based on computational fluid dynamics based on modeling assuming that the first component is composed of at least a third component that has the same molecular formula but different standard generation enthalpy The first component and the second component, one of which consists only of carbon atoms and the other consists of only hydrogen atoms, or the first component and the second component Are assumed to be composed of hydrocarbons having different composition ratios of hydrogen atoms to carbon atoms, respectively, and the mass ratios of the first component and the third component in the pulverized coal are adjusted. Characterized by equalizing the amount of heat generated by the heating value and industrial analysis calculated based on the modeling.

In the simulation method of the present invention, assuming that the volatile component is composed of at least three components, the number of transport equations relating to the volatile component can be limited by fixing the volatile component. In other words, as in the conventional simulation, when the volatile component is assumed to be C _x H _y O _z , for example, if variables (x, y, z) representing different composition ratios are given for each temperature increase rate, the volatile content There is a possibility that the number of transport equations related to the components of the number increases. In view of this, in the present invention, it is possible to reduce the calculation load by restricting the number of transport equations that must be solved during the calculation by constantly fixing the volatile component and eliminating the variable. It is said. In this case, among the three components, the first component and the second component are different in the composition ratio of carbon and hydrogen, so the total amount of carbon and hydrogen in the volatile matter is determined by these two components. Can be represented. Further, in the simulation method of the present invention, the calorific value calculated based on the modeling by adjusting the mass ratio in the volatile component of the first component and the third component is equal to the calorific value by the industrial analysis. By doing so, a more realistic result with respect to temperature can be obtained.

  A simulation process for simulating the combustion of each pulverized coal particle to calculate a simulation result including temperature progress information of each pulverized coal particle, and whether the simulation result obtained by the simulation process satisfies a predetermined termination condition Based on the determination process and the temperature progress information of each pulverized coal particle obtained by the simulation process, the temperature progress information of each pulverized coal particle is the most out of the reference pulverized coal particles stored in the pulverized coal information database. An information extraction step for identifying reference pulverized coal particles having near temperature progress information and extracting physical property information of the pulverized coal including the volatile matter mass ratio of the reference pulverized coal particles from the pulverized coal information database; The first component adjusted to be equal to the calorific value calculated based on the modeling And a component information calculation step of calculating a mass ratio of the third component in the pulverized coal, and when the determination result determines that the simulation result does not satisfy the termination condition, the information extraction step and the component information Execute the calculation step, and reset the physical property information extracted by the information extraction step, each mass ratio calculated by the component information calculation step, and the simulation result obtained by the simulation step as set values in the simulation step It is preferable to execute the simulation process again. In such a simulation method, since the volatile component is modeled as described above, the calculation load is small, and the physical property information of the pulverized coal over the temperature is extracted by the information extraction process, and each value is calculated in the simulation process. Can be reset, so that a more realistic simulation can be performed.

  The component information calculation step calculates each mass proportion of the second component in the volatile matter from the volatile mass proportion obtained in the information extraction step, and also calculates the mass proportion of the first component and the third component. From the total mass ratio, the mass ratio calculation step for obtaining the total mass ratio obtained by adding the mass ratio and the calorific value calculated by the industrial analysis and the calorific value calculated based on the modeling are equal to each other. And a calculation step of calculating a mass proportion of the third component and the third component in the pulverized coal. By this process, the mass ratio of the first component and the third component in the pulverized coal is calculated, and the calorific value calculated based on the modeling is made equal to the calorific value by the industrial analysis, so that the temperature is more It is possible to perform a simulation close to reality.

Here, it is preferable to simulate the first component and the second component on the assumption that one is CH ₄ and the other is C ₂ H ₂ . This is because, by simulating these two components in CH ₄ and C ₂ H ₂ that are actually included in the volatile matter, it is possible to simulate a state closer to the actual pulverized coal combustion.

The volatile component is preferably modeled on the assumption that it is composed of O ₂ , HCN, the first component, the second component, and the third component. This is because by assuming these O ₂ and HCN in addition to the first to third components, it is possible to simulate a state closer to the actual pulverized coal combustion.

  The computer-executable program according to the present invention is characterized in that the procedure of the pulverized coal combustion simulation method is described as a program code, and the computer-readable storage medium according to the present invention includes a pulverized coal combustion A simulation method program is stored.

  The pulverized coal combustion simulation apparatus of the present invention is a pulverized coal combustion simulation apparatus that simulates pulverized coal combustion based on computational fluid dynamics. The volatile content of each pulverized coal particle is expressed by the first component, the first component, and the molecular formula. And the first component and the second component have the same molecular formula as the first component but at least a third component having a different standard generation enthalpy. , One is made up of only carbon atoms and the other is made up of only hydrogen atoms, or the first component and the second component are made of hydrocarbons having different composition ratios of hydrogen atoms to carbon atoms, respectively. A simulation means configured to calculate a simulation result including temperature course information of each pulverized coal particle, and temperature course information for a plurality of reference pulverized coal particles. And a pulverized coal information database in which physical property information including volatile matter mass ratios are respectively stored, and a reference stored in the pulverized coal information database based on temperature course information of each pulverized coal particle obtained by the simulation means The reference pulverized coal particles having the temperature course information closest to the temperature course information of each pulverized coal particle are identified from the pulverized coal particles, and the physical property information including the volatile matter mass ratio of the reference pulverized coal particles is extracted. The mass ratio in the pulverized coal of the first component and the third component adjusted such that the information extraction means configured in the above, the calorific value by the industrial analysis and the calorific value calculated based on the modeling are equal to each other The component information calculation means configured to calculate and the simulation result obtained by the simulation step satisfies a predetermined termination condition. Characterized in that it comprises a configured determining means to determine whether.

  According to the simulation method, the program, and the simulation apparatus of the present invention, it is possible to perform a highly accurate calculation that is light in calculation and more realistic.

  First, a modeling method used in the simulation method of the present invention will be described.

In this modeling method, the volatile matter released when the pulverized coal particles are thermally decomposed due to a temperature rise has a first component, a second component having a molecular formula different from the first component, and the first component. Modeling the combustion of pulverized coal on the assumption that it comprises at least a third component having the same molecular formula but different standard enthalpy of production, wherein the first component and the second component are: It is assumed that one is made up of only carbon atoms and the other is made up of only hydrogen atoms, or that the first component and the second component are made of hydrocarbons having different composition ratios of hydrogen atoms to carbon atoms, respectively. To do. For example, it may be assumed that one of the first component and the second component is H and the other is C, and one of the first component and the second component is CH ₄ and the other is C. ₂ H ₄ may be assumed. That is, the first component and the second component are represented by molecular formulas having different composition ratios of hydrogen atoms to different carbon atoms, so that the total amount of carbon atoms and hydrogen atoms in the volatile matter can be expressed as two. It can be expressed as a component. Also preferably, it is assumed as an actual component to be released as volatiles in view that there is CH ₄ and C ₂ H _2, the CH _4, C ₂ H ₂ as a first component and a second component That is. Furthermore, in addition to the first to third components, it is preferable to assume that the volatile component is composed of O ₂ and HCN which are listed as components that are actually released as a volatile component, because a simulation closer to reality can be achieved.

  In the present invention, it is assumed that the volatile component is composed of components fixed in this way, and since there are no components represented by variables, the number of transport equations to be solved in the simulation is fixed, so the calculation load is small.

  By the way, in the modeling assuming the volatile component, a third component having the same molecular formula as that of the first component but having a different standard generation enthalpy is defined. By defining the third component in this way, the first component and the third component are set so that the calorific value of the volatile component obtained based on the first modeling matches the calorific value of the volatile component according to the industrial analysis. As a result, a more realistic simulation can be performed with respect to the temperature. The adjustment of the mass ratio between the first component and the third component will be specifically described below.

First, in order to obtain the mass ratio of each component, the volatile component is CH ₄ as the component defined by the molecular formulas representing the first component and the third component, C ₂ H ₂ as the second component, Modeling is performed with O ₂ and HCN. Here, the first component and the third component are not separately defined, but are collectively defined as components defined by molecular formulas representing them. As will be described later, the mass ratio of this component is the first component. Is equal to the sum of the mass proportion of the component and the mass proportion of the third component. In this case, the mass ratio of each component of the volatile component in coal is represented by the following formula (1.1).

ここで、ｍ_volaは石炭中揮発分の質量割合（kg/kg-coal）、ｍ_CH4は石炭中ＣＨ₄として放出される揮発分の質量割合（kg/kg-coal）、ｍ_C2H2は石炭中Ｃ₂Ｈ₂として放出される揮発分の質量割合（kg/kg-coal）、ｍ_O2は石炭中Ｏ₂として放出される揮発分の質量割合（kg/kg-coal）、ｍ_HCNは石炭中ＨＣＮとして放出される揮発分の質量割合（kg/kg−coal）である。また、各成分を構成する元素自体は以下の式で表される。

Where m _vola is the mass ratio of volatiles in coal (kg / kg-coal), m _CH4 is the mass ratio of volatiles released as CH _{4 in} coal (kg / kg-coal), and m _C2H2 is in coal Mass ratio of volatile matter released as C ₂ H ₂ (kg / kg-coal), m _O2 is mass ratio of volatile matter released as O _{2 in} coal (kg / kg-coal), m _HCN in coal It is the mass ratio (kg / kg-coal) of the volatile matter released as HCN. Moreover, the element itself which comprises each component is represented by the following formula | equation.

m _x is the mass ratio of element X in coal (kg / kg-coal), P _x is the industrial analysis value (arrival base mass fraction), U _x is the elemental analysis value (anhydrous ashless base mass fraction) , Subscripts C, vola, C, char, vola, H, O, N, ash, and moist indicate volatile carbon, char carbon, total volatile content, hydrogen, oxygen, nitrogen, ash, and moisture, respectively. . In formula (1.7), η _N represents the ratio of N released as HCN in the element N in coal.

By solving these equations (1.2) to (1.7) simultaneously, mass ratios of CH ₄ , C ₂ H ₂ , O ₂ and HCN in the volatile matter can be obtained.

  Next, from these mass ratios, the mass ratios of the first component and the third component are calculated based on the industrial analysis values. In order for the calorific value GCV based on the industrial analysis to coincide with the calorific value based on the modeling, the following equation (2.1) is established.

・・・・・（２．１）

(2.1)

f _x is the mass fraction in volatiles, determined from the mass ratio. Δhx indicates the calorific value per unit. The subscripts C, char, vola, and moist indicate char carbon, the total amount of volatile matter, and moisture, respectively. Also, the calorific value Δh _C2H2 of C ₂ H ₂ and the calorific value Δh _char of _char are defined. In addition, the amount of heat Δh _dev and the latent heat of vaporization Δh _lat necessary for the thermal decomposition reaction of volatile components in coal are known values. Note that Δh _GCV is an adjustment value for matching the calorific value based on industrial analysis and the calorific value based on modeling.

Here, by introducing the first component and the third component having different calorific values into the formula (2.1) and adjusting their mass ratios, the adjustment value Δh _GCV is eliminated, and only the calorific value of each component is obtained. Redefine the amount of heat generated by modeling. Therefore, the calorific value Delta] h _CH4high per unit mass of the high first component of standard enthalpy of formation, per unit mass of the lower third component of standard enthalpy heat value Delta] h _CH4low, and for adjusting the heat value of When the equation (2.1) is rewritten using the calorific value adjustment parameter ξ (takes any value between 0 and 1 and is also referred to as the existence ratio hereinafter), it can be expressed by the following equation (2.2). .

・・・・・（２．２）

(2.2)

Therefore, by substituting a known value such as an industrial analysis value and a specified value into this formula (2.2), the first calorific value based on the industrial analysis and the calorific value based on the modeling are matched. The mass ratio of the component and the existing ratio ξ of the third component can be obtained. Then, using (m _vola × f _CH4 ) which is the mass proportion of CH ₄ and the abundance ratio ξ, the mass proportion of the first component is (m _vola × f _CH4 × (1-ξ)), third The mass ratio of the component can be calculated as (m _vola × f _CH4 × ξ). That is, the specified mass ratio of CH ₄ is the sum of the mass ratio of the first component and the mass ratio of the third component.

  As described above, by adjusting the mass ratio (existence ratio) of the first component and the third component so that the calorific value based on the modeling and the calorific value based on the industrial analysis are equal, the temperature can be further increased. Realistic simulation can be performed.

  Hereinafter, a simulation method and a simulation apparatus using the modeling method will be described.

  FIG. 2 is a block diagram showing an outline of the pulverized coal combustion simulation apparatus of the present invention. The simulation apparatus 1 includes a CFD calculation unit 11, a determination unit 12, a pulverized coal information database 13, an information extraction unit 14 that extracts information on pulverized coal particles from the pulverized coal information database 13, a component information calculation unit 15, And an analysis value storage unit 16.

The CFD calculating unit 11 sets predetermined initial values for all variables necessary for CFD calculation, and stores the industrial analysis value and the elemental analysis value in the analysis value storage unit 16, and the setting unit 111 A CFD calculation unit 112 that performs numerical simulation of combustion of pulverized coal particles based on the above modeling with the set value set, and calculates a simulation result including temperature progress information of each pulverized coal particle. Here, the temperature progress information of the pulverized coal particles includes a set of the temperatures T _j of the pulverized coal particles at a predetermined time t _j (0 ≦ j ≦ n, j and n are positive integers). Information indicating how the temperature has changed over time.

  The determination unit 12 is connected to the CFD calculation unit 112 of the CFD calculation unit 11 and is configured to determine whether the simulation result obtained by the CFD calculation unit 112 satisfies a predetermined termination condition.

  The pulverized coal information database (pulverized coal information DB) 13 is a database in which temperature progress information with respect to the reference pulverized coal particles and physical property information including the mass ratio of volatile components are stored in advance, and is connected to the information extraction unit 14. .

  The information extraction unit 14 is connected to the pulverized coal information database 13 and is also connected to the CFD calculation unit 112 and the determination unit 12. The information extraction unit 14 is configured to operate when the determination unit 12 determines that the end condition is not satisfied. And the information extraction means 14 is each pulverized coal particle from the reference pulverized coal particles stored in the pulverized coal information database 13 based on the temperature progress information of each pulverized coal particle obtained by the CFD calculation unit 112. The physical property information of the pulverized coal including the volatile content ratio of the reference pulverized coal particles having the closest temperature progress information to the reference is extracted.

  The component information calculation unit 15 is connected to the information extraction unit 14 and the analysis value storage unit 16. The analysis value storage unit 16 is connected to the setting unit 111 of the CFD calculation unit 11 and stores the industrial analysis value and elemental analysis value of pulverized coal by the industrial analysis input by the setting unit 111.

  The component information calculation means 15 calculates the mass ratio in the volatile component of the first component and the third component so that the calorific value calculated based on the above modeling and the calorific value by the industrial analysis are equal. It is configured as follows.

  The information extraction unit 14, the component information calculation unit 15, and the CFD calculation unit 112 are connected to the setting unit 111 of the CFD calculation unit 11, respectively, and the simulation result by the CFD calculation unit 112 is extracted by the information extraction unit 14. The physical property information of the pulverized coal and the mass ratio of each component calculated by the component information calculation means 15 are respectively input to the setting unit 111 and set as variables in the next CFD calculation.

  That is, in the present invention, the pulverized coal information database 13 and the information extracting means 14 are provided, whereby physical property information of the pulverized coal according to the temperature rising rate of each pulverized coal particle can be obtained. By resetting in the CFD calculation, the emission rate and total amount of volatile matter not considered in the conventional CFD calculation, the type and particle size of each pulverized coal particle, and the furnace in which the pulverized coal particle is charged The pulverized coal combustion simulation can be performed in consideration of the charging position.

  And since the component in a volatile matter is being fixed, in the CFD calculation means 11, since the number of the transport equations which should be solved concerning the component of a volatile matter is limited, the load of calculation becomes small. Further, the calorific value calculated based on the above-described modeling by the component information calculating means 15 and the calorific value by the industrial analysis are adjusted to be equal to each other in the volatile content of the first component and the third component. By calculating the mass ratio, it is possible to perform a simulation closer to reality with respect to the temperature.

  Hereinafter, a simulation method using the simulation apparatus 1 will be described with reference to FIG.

  FIG. 3 is a flowchart for explaining the pulverized coal combustion simulation method of the present invention. As shown in the figure, first, initial values, industrial analysis values, and elemental analysis values are input and set to all variables used in the CFD calculation by the setting unit 111 of the CFD calculation means 11 (S21). The industrial analysis value is stored in the analysis value storage unit 16.

  Next, based on the initial value set by the setting unit 111, the CFD calculation unit 112 incorporates the above-described modeling method to perform a pulverized coal combustion simulation, and calculates a simulation result including temperature progress information of each pulverized coal particle ( CFD calculation step: S22). In this case, the CFD calculation unit 112 has a small calculation load because the volatile component is fixed.

  Thereafter, the determination unit 12 determines whether or not the obtained simulation result satisfies the termination condition (determination step: S23). When the simulation result satisfies the termination condition (S23: YES), the simulation is terminated.

  If the simulation result does not satisfy the termination condition (S23: NO), the information extraction unit 14 uses the pulverized coal information database 13 based on the temperature progress information of each pulverized coal particle obtained in the CFD calculation step S22. To extract physical property information of the reference pulverized coal particles having the temperature lapse information closest to the temperature lapse information of each pulverized coal particle (information extraction step: S24).

  Based on the physical property information of the pulverized coal and the industrial analysis information stored in the analysis value storage unit 16 (see S21), the calorific value calculated based on the above-described modeling is equal to the calorific value based on the industrial analysis. The mass ratio in the volatile content of the first component and the third component adjusted as described above is calculated (component information calculation step: S25).

  Thereafter, the physical property information of the pulverized coal extracted in the information extraction step S24 and the mass ratio of each component calculated in the component information calculation step S25 are respectively input to the setting unit 111 of the CFD calculation unit 11, and the CFD calculation step The setting value is reset (S26), and the CFD calculation step S22 is performed again. Then, these processes (S22 to S26) are repeated as one cycle until it is determined that the simulation result obtained by executing the CFD calculation process S22 again satisfies the termination condition described above.

  As described above, according to the simulation method of the present invention, it is possible to obtain physical property information of pulverized coal according to the temperature rising rate of each pulverized coal particle, and by resetting it in the CFD calculation, the conventional CFD can be obtained. The pulverized coal combustion simulation was performed in consideration of the release rate and total amount of volatile components that had not been considered in the calculation, the type and particle size of each pulverized coal particle, and the charging position in the furnace where the pulverized coal particle was charged. It can be carried out. In addition, since the volatile component is fixed, the calculation load is small. Moreover, when modeling the component of volatile matter in this way, a simulation result closer to reality can be obtained with respect to temperature by the component information calculation step S25.

Hereinafter, with reference to FIGS. 4 and 5, a simulation apparatus and simulation method detailed pulverized coal combustion, the components defined by the molecular formula which represents the first component and the third component CH ₄ (i.e. the first component Is _{assumed to} be CH _4high , the third component is CH _4low ), the second component is C ₂ H _2, and further O ₂ and HCN are assumed. FIG. 4 is a block diagram of the simulation apparatus, and FIG. 5 shows a flowchart of the simulation method. 4, the same constituent elements as those in FIG. 2 are denoted by the same reference numerals, and in FIG. 5, the same constituent elements as those in FIG. 3 are denoted by the same reference numerals.

  First, the CFD calculation means 11 will be described in detail. In the setting unit 111 of the CFD calculation unit 11, the value of the variable in the CFD calculation unit 112, the industrial analysis value, and the elemental analysis value are input. Based on this set value, the CFD calculation unit 112 performs simulation by incorporating the above-described modeling. Hereinafter, the calculation method of the discharge | release rate of the volatile component discharge | released from the pulverized coal particle performed in a CFD calculation part is demonstrated.

  The release rate of volatile components released from the pulverized coal particles (volatile component release rate dV / dt) is calculated by the following equations (3.1) and (3.2) (Arrhenius type volatile component release rate equation). The

ここで、Ｖ^*は微粉炭粒子中の全揮発成分量、Ｖは微粉炭粒子から放出された揮発成分量を示す。

Here, V ^* represents the total amount of volatile components in the pulverized coal particles, and V represents the amount of volatile components released from the pulverized coal particles.

ここで、Ｋ_vは揮発成分放出速度係数、Ａ_vは頻度因子、Ｅ_vは活性化エネルギー、Ｒは気体定数、Ｔ_jは時刻ｔ_jにおける微粉炭粒子の温度を示す。

Here, K _v is shown volatiles release rate coefficient, A _v is the frequency factor, E _v is the activation energy, R is the gas constant, and the temperature of the pulverized coal particles in T _j at time t _j.

That is, by substituting the temperature T _j of the pulverized coal particles at time t _j in Equation (3.2) to calculate the volatile ingredient release rate coefficient K _v of the pulverized coal particles at the temperature T _j. Then, by substituting the obtained K _v into Equation 1, the volatile component release rate dV / dt of the pulverized coal particles at time t _j can be calculated.

Here, as the total volatile component amount V ^* in the pulverized coal particles in the formula (3.1), different values are used according to the temperature progress information of each pulverized coal particle. That is, in the pulverized coal combustion simulation of the present embodiment, as will be described later, based on temperature course information that changes according to the type and particle diameter of each pulverized coal particle and the charging position in the furnace where the pulverized coal particle is charged. V ^* , _Av and _Ev are calculated, and the volatile component emission of each pulverized coal particle considering the type and particle diameter of each pulverized coal particle and the charging position in the furnace where the pulverized coal particle is charged. The speed dV / dt can be calculated.

In the conventional pulverized coal combustion simulation, the total volatile component amount V ^* in the pulverized coal particles depends only on the mass of the pulverized coal particles, and the type and particle size of the pulverized coal particles and the furnace in which the pulverized coal particles are charged. A value that does not depend on the input position is used. Therefore, in the conventional pulverized coal combustion simulation, when calculating the volatile component release rate dV / dt of the pulverized coal particles, the type and particle diameter of each pulverized coal particle and the charging position in the furnace where the pulverized coal particles are charged. However, the pulverized coal combustion simulation according to the present embodiment does not have such a problem.

  In this way, the CFD calculating means 11 performs a simulation for calculating the volatile matter release rate. This simulation can be realized using general-purpose thermal fluid analysis software such as STAR-CD (registered trademark), FLUENT (registered trademark), CFX (registered trademark). Reference 1 (Mitsubasa Hohara and Sasaaki Omiya, Computational Fluid Dynamics-Fundamentals and Applications, University of Tokyo Press (1992)), and Reference 2 (Takehisa Omiya, Hiroshi Miyake and Satoru Yoshizawa, Computational Fluid Dynamics of Turbulence) -Model and calculation method, University of Tokyo Press (1998)). The simulation result is output to the determination unit 12, and the determination unit 12 determines whether the end condition is satisfied. As the termination condition, the termination condition incorporated in the general-purpose thermal fluid analysis software described above may be used as it is. If not satisfied, the simulation result is input to the information extraction means 14 connected to the pulverized coal information database 13.

Here, the pulverized coal information database 13 will be described. In the pulverized coal information database 13, temperature elapsed information and physical property information are stored in association with each reference pulverized coal particle. As the physical property information, the volatile component ratio m _{vola in} coal for obtaining the total volatile component amount V ^* _r which is a variable in the formula (3.1), the frequency factor A _vr, and the activation energy E _vr are stored. ing. V ^* _r can be determined by the product of m _vola and the mass of the particles. Note that these data stored in the pulverized coal information database 13 may be data obtained by actual experiments, or heat based on a FLASHCHAIN model such as PC Coal Lab (registered trademark), for example. Data calculated using decomposition simulation software may be used.

  The information extraction unit 14 includes a temperature difference calculation unit 141 connected to the CFD calculation unit 112 and the determination unit 12, a specification unit 142 connected to the temperature difference calculation unit 141, and an extraction unit 143 connected to the specification unit 142. It has.

In the temperature difference calculation means 141, for each temperature progress information of each pulverized coal particle obtained by the CFD calculating unit 112, for the temperature progress information of all the reference pulverized coal particles stored in the pulverized coal information database 13, The numerical value error _i shown in the following formula (3.3) is calculated.

式中、Ｔ_jは微粉炭粒子の時刻ｔ_jにおける温度を示し、Ｔ_ri,jは微粉炭情報データベースに格納されているｉ番目の参照微粉炭粒子の時刻ｔ_jにおける温度を示す。

In the equation, T _j represents the temperature of the pulverized coal particles at time t _j , and T _{ri, j} represents the temperature of the i-th reference pulverized coal particles stored in the pulverized coal information database at time t _j .

The specifying means 142 specifies the reference pulverized coal particles having the smallest value among all the obtained error _i for each pulverized coal particle. Next, the extraction means 143 extracts from the pulverized coal information database 13 the volatile content ratio m _{vola in} the coal of the reference pulverized coal particles specified by the specifying means 142, the frequency factor A _vr, and the activation energy E _vr. . As a result, it is possible to extract the volatile matter ratio m _{vola in} the coal of the reference pulverized coal particles having the closest temperature course information to each pulverized coal particle, the frequency factor A _vr, and the activation energy E _vr , respectively.

  The component information calculation means 15 includes a mass ratio calculation means 151 connected to the information extraction means 14 and the analysis value storage section 16, and a calculation means 152 connected to the mass ratio calculation means 151 and the analysis value storage section 16. ing.

The mass ratio calculation unit 151 obtains the Px and Ux from the industrial analysis value and the elemental analysis value input in advance by the CFD calculation unit 11 in the analysis value storage unit 16 to obtain the above (1.2) to (1.7). ) To calculate the respective mass ratios of O ₂ , HCN, C ₂ H ₂ , and CH ₄ .

The calculation means 152 calculates the existence ratio ξ based on the formula (2.2) from each mass ratio obtained by the mass ratio calculation means 151 and the industrial analysis value stored in the analysis value storage unit 16, and the standard It is comprised so that the mass ratio of _CH4high with high production _| generation enthalpy and _CH4low with low can be calculated.

That is, in this embodiment, the calorific value based on modeling is adjusted to match the calorific value by industrial analysis by adjusting the mass ratio of CH _4high with high standard generation enthalpy and low CH _4low, and more realistically. Simulation is possible.

The extraction means 143 of each information extraction means 14 and the mass ratio calculation means 151 and the calculation means 152 of the component information calculation means 15 are respectively connected to the setting unit 111 of the CFD calculation means 11, whereby the mass ratio calculation means Each mass ratio calculated by 151 and the mass ratio of CH _4high having a high standard generation enthalpy obtained by the calculation means 152 and low CH _4low are respectively obtained from the setting unit 111 in the same manner as the values obtained from the information extraction means 14. It is configured to be reset.

Thus, in the present invention, the information extraction means 14 calculates the numerical value error _i shown in the equation (3.3), easily specifies the reference pulverized coal particles, and extracts the physical property information of the pulverized coal. Can do. Further, a component information calculation means 15 of the present invention, by adjusting the proportion between the high CH _4High and low CH _4Low the standard enthalpy of formation, consistent values of the heating amount based on the modeling easily the amount of heat generated by industrial analysis It is possible to perform a simulation closer to reality.

  The details of the simulation method assuming the volatile component as described above will be described below with reference to FIG.

  First, the initial value, the industrial analysis value, and the elemental analysis value are input and set to all variables used for the CFD calculation by the setting unit 111 of the CFD calculation means 11 (S21). The industrial analysis value is stored in the analysis value storage unit 16.

  Next, based on the initial value set by the setting unit 111, a pulverized coal combustion simulation is performed by the CFD calculation unit 112, and a simulation result including temperature progress information of each pulverized coal particle is calculated (CFD calculation step: S22).

  Thereafter, the determination unit 12 determines whether or not the obtained simulation result satisfies the termination condition (determination step: S23). If the end condition is satisfied, the simulation ends.

If the simulation result does not satisfy the termination condition, the reference pulverized coal particles are based on the temperature progress information of each pulverized coal particle obtained by the CFD calculation step S22 by the temperature difference calculating unit 141 of the information extracting unit 14. The numerical value error _i shown in the above equation (3.3) is calculated with respect to the temperature progress information (temperature difference calculation step: S24-1). Next, the specifying means 142 specifies the reference pulverized coal particles having the smallest value among all the obtained error _i for each pulverized coal particle (identifying step: S24-2). Thereafter, the physical property information of the reference pulverized coal particles having the closest temperature course information for each pulverized coal particle specified by the specifying process, that is, the volatile content ratio m _{vola in the} coal, the frequency factor A _vr, and the activation energy E Each _vr is extracted (extraction step: S24-3).

Based on the volatile content information and the industrial analysis value and elemental analysis value stored in the analysis value storage unit 16 (see S21), the mass ratio calculation means 151 is used to calculate CH ₄ , C ₂ H ₂ , O ₂ to obtain the mass ratio of HCN (mass ratio calculation step: S25-1).

The presence proportion of the calculating means 152, from the industrial analysis and the mass ratio, the calorific value and high CH _4High the standard enthalpy as heating value and are equal based on industrial analysis and low CH _4Low based on modeling ξ is calculated based on the formula (2.2), and the mass ratio is calculated (calculation step: S25-2).

  Thereafter, the physical property information of the pulverized coal extracted in the information extraction step S24, the mass proportion calculated in the mass proportion calculation step S25-1, and the mass proportion calculated in the calculation step S25-2 are respectively calculated by the CFD calculation unit 11. The value is input to the setting unit 111 and reset as a setting value for the CFD calculation process (S26), and the CFD calculation process S22 is performed again. Then, these steps (S22 to S26) are repeated as one cycle until it is determined that the simulation result obtained in the CFD calculation step S22 satisfies the above-described termination condition.

Thus, in this invention, by calculating the numerical value error _i shown by Formula (3.3) in temperature difference calculation process S24-1, a reference | standard pulverized coal particle is specified easily, Physical property information can be extracted. Also, in calculation step S25-2, the calorific value based on modeling is easily adjusted to match the industrial analysis value by adjusting the mass ratio between CH _4high with high standard generation enthalpy and low CH _4low. can do.

In the simulation method and apparatus described above, the calorific value is adjusted by dividing CH ₄ into high enthalpy CH _4high and low enthalpy CH _4low , but C ₂ H ₂ is divided into high enthalpy and low enthalpy. The calorific value may be adjusted separately. Further, it may be assumed that the third component has a higher standard generation enthalpy than the first component.

In the embodiment described above, by calculating the error _i described above for each pulverized coal particle as a preferred aspect, the physical property information of the reference pulverized coal particle having the closest temperature progress information for each pulverized coal particle is extracted. Although the embodiment has been described, another extraction method may be used as long as the physical property information can be extracted.

  Furthermore, in this embodiment, the volatile component velocity of each pulverized coal particle was calculated using the above-described Arrhenius-type volatile component release rate equation, but the Arrhenius-type volatile component release rate equation that can be used in the present invention. Is not limited to this. For example, a combination of a plurality of Arrhenius-type volatile component release rate equations may be used as the volatile component release rate equation.

Moreover, in embodiment, as above-mentioned, using the temperature progress information of the pulverized coal particle obtained by the CFD calculation process as it is, the volatile content ratio m _{vola in} coal, the frequency factor A _vr, and the activation energy E _vr However, since the temperature course information of the pulverized coal particles obtained by the CFD calculation process is obtained discretely, the time t _j of the temperature course information of the pulverized coal particles obtained by the CFD calculation process, and the pulverized coal information database 13 may be different from the time t _j of the temperature lapse information of the reference pulverized coal particles stored in 13. In this case, the temperature T _j of the pulverized coal particles at the time t _j of the reference pulverized coal particles is supplemented using the following formula (3.4), and the volatile component release rate dV / dt is calculated using them. be able to.

式中、ｔ_mはＣＦＤ計算工程により得られた時刻のうち、時刻ｔ_jよりも早く、かつ時刻ｔ_jに一番近い時刻を示し、Ｔ_mは時刻ｔ_mにおける微粉炭粒子の温度を示す。また、ｔ_m+1はＣＦＤ計算工程により得られた時刻のうち、時刻ｔ_jよりも遅く、かつ時刻ｔ_jに一番近い時刻を示し、Ｔ_m+1は時刻ｔ_m+1における微粉炭粒子の温度を示す。

In the formula, t _m indicates a time earlier than the time t _j and closest to the time t _j among the times obtained by the CFD calculation process, and T _m indicates the temperature of the pulverized coal particles at the time t _m . . Also, t m _{+ 1} among the time obtained by the CFD calculation process, slower than the time t _j, and shows the closest time to the time t _j, the pulverized coal in the T m _{+ 1} is the time t _{m + 1} Indicates the temperature of the particles.

It is a graph for demonstrating the component of pulverized coal particle. It is a block diagram for demonstrating the simulation apparatus of this invention. It is a flowchart for demonstrating the simulation method of this invention. It is a block diagram for demonstrating the detail of a simulation apparatus. It is a flowchart for demonstrating the detail of the simulation method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Simulation apparatus 11 Calculation means 12 Determination means 13 Pulverized coal information database 14 Information extraction means 15 Component information calculation means 16 Analysis value storage part 111 Setting part 112 Calculation part 141 Temperature difference calculation means 142 Specification means 143 Extraction means 151 Mass ratio calculation means 152 Calculation means

Claims (8)

  Volatile matter released by pyrolysis of pulverized coal particles due to temperature rise is defined as the first component, the second component having a molecular formula different from that of the first component, and the first component and the molecular formula being equal to the standard. A simulation method of pulverized coal combustion for simulating combustion of pulverized coal based on computational fluid dynamics based on modeling assuming that the generation enthalpy includes at least a third component having a different generation enthalpy. One of the component and the second component is composed of only a carbon atom and the other is composed of only a hydrogen atom, or the first component and the second component are each composed of a hydrogen atom with respect to a carbon atom. It is assumed that the ratios are composed of hydrocarbons, and the calorific value calculated based on the modeling by adjusting the mass ratio of the first component and the third component in the pulverized coal and the industrial Simulation method for pulverized coal combustion, characterized in that to equalize the amount of heat generated by analysis. A simulation step of simulating the combustion of each pulverized coal particle and calculating a simulation result including temperature course information of each pulverized coal particle;
A determination step of determining whether or not a simulation result obtained by the simulation step satisfies a predetermined termination condition;
Based on the temperature course information of each pulverized coal particle obtained by the simulation step, the temperature course information closest to the temperature course information of each pulverized coal particle from the reference pulverized coal particles stored in the pulverized coal information database is included. An information extraction step of identifying reference pulverized coal particles and extracting physical property information of pulverized coal including the volatile matter mass ratio of the reference pulverized coal particles from the pulverized coal information database;
From the component information calculation process which calculates the mass ratio in the pulverized coal of the 1st component and the 3rd component adjusted so that the calorific value by industrial analysis and the calorific value calculated based on the modeling may become equal Become
When it is determined by the determination step that the simulation result does not satisfy the termination condition, the information extraction step and the component information calculation step are executed, and the physical property information extracted by the information extraction step and the component information calculation step are calculated. 2. The simulation of pulverized coal combustion according to claim 1, wherein each of the measured mass ratios and the simulation result obtained by the simulation process are reset as set values in the simulation process, and the simulation process is executed again. Method.   The component information calculation step calculates each mass proportion of the second component in the volatile matter from the volatile matter mass proportion obtained in the information extraction step, and also calculates the mass proportion of the first component and the third component. From the total mass ratio, the mass ratio calculation step for obtaining the total mass ratio obtained by adding the mass ratio and the calorific value calculated by the industrial analysis and the calorific value calculated based on the modeling are equal to each other. A pulverized coal combustion simulation method according to claim 2, further comprising: a calculating step of calculating a mass ratio of the component and the third component in the pulverized coal. The pulverized coal combustion according to any one of claims 1 to 3, wherein the first component and the second component are simulated on the assumption that one is CH ₄ and the other is C ₂ H _2. Simulation method. The volatile matter is modeled on the assumption that it is composed of O ₂ , HCN, the first component, the second component, and the third component. The pulverized coal combustion simulation method according to any one of the above.   A computer-executable program, characterized in that the procedure of the pulverized coal combustion simulation method according to any one of claims 1 to 5 is described as a program code.   A computer-readable storage medium storing a program of the pulverized coal combustion simulation method according to claim 6. In a simulation apparatus for pulverized coal combustion that simulates pulverized coal combustion based on computational fluid dynamics,
The volatile content of each pulverized coal particle includes at least a first component, a second component having a molecular formula different from that of the first component, and a third component having a molecular formula equal to that of the first component but having a different standard enthalpy of generation. Assuming that the first component and the second component are composed of only one carbon atom and the other only a hydrogen atom, or the first component and the second component. And a simulation means configured to calculate a simulation result including temperature course information of each pulverized coal particle, each comprising a hydrocarbon having a different composition ratio of hydrogen atoms to carbon atoms,
A pulverized coal information database in which temperature information for a plurality of reference pulverized coal particles and physical property information including volatile matter mass ratios are respectively stored;
Based on the temperature course information of each pulverized coal particle obtained by the simulation means, the temperature course information closest to the temperature course information of each pulverized coal particle from the reference pulverized coal particles stored in the pulverized coal information database is obtained. Information extracting means configured to identify the reference pulverized coal particles and to extract physical property information including the volatile matter mass ratio of the reference pulverized coal particles,
A component configured to calculate the mass ratio in the pulverized coal of the first component and the third component adjusted so that the calorific value by industrial analysis and the calorific value calculated based on the modeling are equal. Information calculation means;
A simulation apparatus for pulverized coal combustion, comprising: a determination unit configured to determine whether a simulation result obtained by the simulation step satisfies a predetermined termination condition.

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