JP2003161416A - Fluid state predicting method in fluidized bed combustion equipment and operation method of fluidized bed combustion equipment using this method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple fluid state predicting method in fluidized bed combustion equipment superior in productivity, superior in versatility and universality regardless of a fuel kind, a kind of desulfurizing agent and fluidity improver and a blending quantity, and superior in reliability, and also to provide an operation method of the fluidized bed combustion equipment using this method. <P>SOLUTION: This fluid state predicting method in the fluidized bed combustion equipment is provided with a conversion content calculating process for calculating the conversion content of standard oxide of a molten element from the content of the molten element constituting molten ash, a component ratio calculating process for calculating the respective component ratios of the standard oxide in the molten ash on the basis of the conversion content of the standard oxide calculated by the process, and a molten state estimating process for estimating a molten liquid quantity of the molten ash generated in a prescribed temperature range in a thermodynamic balancing state on the basis of pressure and the respective component ratios calculated by the process. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for predicting a fluidized state in a fluidized bed combustion apparatus and a method for operating a fluidized bed combustion apparatus using the method.

[0002]

2. Description of the Related Art In recent years, in power plants and refuse incinerators,
BACKGROUND ART A fluidized bed combustion apparatus that fluidizes fuel such as coal or dust and efficiently burns it has been researched and developed. By using the fluidized bed combustion device, it is possible to construct a steam turbine power generation system that is driven by the steam generated from the heat transfer tubes arranged in the fluidized bed combustion device. Also, by using a pressurized fluidized bed combustion device that fluidizes and burns fuel under the condition that the oxygen partial pressure in the combustion device is increased by pressurizing with air from the compressor, in addition to steam turbine power generation, combustion A combined power generation system with improved thermal efficiency can be constructed by combining with gas turbine power generation that uses exhaust gas. In a fluidized bed combustion device, limestone (calcium carbonate) or the like is used as a fluidizing medium that constitutes a fluidized bed, and as a desulfurizing agent that captures SOx generated in a fuel combustion process in a furnace by a gypsum reaction and desulfurizes it. It is used. However, the conventional fluidized bed combustion apparatus has the following problems. (1) In the lower part of the combustion device, from the disperser through which the gas for forming the fluidized bed passes from below to the vicinity of the fuel nozzle where fuel such as coal is injected into the combustion device, volatile components in the fuel are burned, etc. Due to the above, a high temperature state of about 1100 to 1300 ° C. partially appears. In such a high temperature state, the ash content containing Si and Al (including the ash content contained in the char) is released when the fuel burns, and molten ash is formed. The molten ash forms a lump by successively adhering desulfurizing agents such as limestone existing around it. Further, the molten ash containing Si or Al and adhering to the desulfurizing agent lowers the melting point of the desulfurizing agent due to the interaction with Ca contained in the desulfurizing agent to be melted, and further causes the grain growth of the agglomerates. In the lower part of the combustor, the fluidity of the desulfurizing agent is lowered due to the presence of such molten ash, and in particular, the residence time of a lump having a large particle size and a large bulk density is prolonged,
Causes further poor flow and agglomeration. Therefore, it becomes difficult to carry out a stable continuous operation of the fluidized bed combustion device for a long period of time, and in a remarkable case, the fluidized bed combustion device adheres to a heat transfer pipe or an inner wall arranged in the fluidized bed combustion device. Had a problem that it had a great adverse effect on the operation of. Therefore, in recent years, in order to stabilize the fluidized state by preventing poor flow and agglomeration of the fluidized medium of the fluidized bed combustion apparatus,
Various studies have been made on the operation method of a fluidized bed combustion apparatus.

A conventional technique is disclosed in Japanese Patent Laid-Open No. 58-160.
Japanese Patent No. 710 (hereinafter referred to as "A") discloses "a fluidized bed combustion method of a mineral fuel for supplying a powdery aluminum slag containing 10% or more of metallic aluminum together with a mineral fuel such as coal".

Japanese Patent Laid-Open No. 2000-297915 (hereinafter referred to as "B") discloses that "either one or both of a calcium compound and a magnesium compound is supplied to prevent molten ash from adhering to a fluid medium or an inner wall of a device. A method for operating a layered combustion furnace "is disclosed.

[0005]

However, the above conventional techniques have the following problems. (1) In the technologies described in the publications (a) and (b), the content of ash components and aluminum, calcium, magnesium, etc., differs depending on the fuel type, so when the fuel type changes, aluminum slag, calcium compound, magnesium There was a problem that the optimum addition amount of the compound could not be grasped, it was necessary to actually add the compound to check the fluidized state, trial and error were required, and workability was remarkably inferior. (2) Depending on the fuel type, even if an aluminum slag, a calcium compound, or a magnesium compound is added, the fluid state is not improved and poor fluidity or agglomeration occurs. Since such fuel cannot be used, there is a problem that the time and cost required for purchasing the fuel are significantly impaired and the workability is deteriorated. (3) Since the amount of calcium present in the combustion device varies depending on the type and blending amount of desulfurizing agent, it is not possible to grasp the optimum amount of aluminum slag, calcium compounds, etc. It had to be confirmed, trial and error were required, and the workability was extremely poor.

The present invention solves the above-mentioned conventional problems and is simple and excellent in productivity. Further, it is excellent in versatility and flexibility regardless of types and blending amounts of fuel species, desulfurizing agents and flow improvers and is reliable. An object of the present invention is to provide a method for predicting a fluidized state in a fluidized bed combustor having excellent properties. Further, the present invention is an optimal desulfurizing agent, fuel, and
An object of the present invention is to provide a method for operating a fluidized bed combustor using a fluidized state prediction method in a fluidized bed combustor which is excellent in workability and productivity, in which the type and amount of the fluidity improver can be determined in advance.

[0007]

In order to solve the above-mentioned conventional problems, a fluidized state predicting method in a fluidized bed combustion apparatus and an operating method of a fluidized bed combustion apparatus using the same according to the present invention have the following constitutions. ing.

According to a first aspect of the present invention, there is provided a method for predicting a fluidized state in a fluidized bed combustion apparatus, comprising: a fuel, a combustion ash obtained by burning the fuel, and a desulfurization agent, each of which contains the combustion ash and the desulfurization agent. From the content of the molten element constituting the molten ash produced by melting, the combustion ash, a conversion content calculation step of calculating the conversion content of the standard oxide of the molten element of each of the desulfurization agent, and Combustion ash, and the desulfurizing agent, a mixing ratio of supplied per unit time, based on the reduced content of the standard oxide calculated in the reduced content calculation step, based on the molten ash, Generated within a predetermined temperature range in a thermodynamic equilibrium state based on a component ratio calculation step of calculating each component ratio of the standard oxide, each component ratio calculated in the component ratio calculation step, and pressure. Said molten ash It has a melting state estimation step of estimating the amount of melt, the configuration with. With this configuration, the following effects can be obtained. (1) The melt of molten ash obtained by melting the combustion ash adheres to the surface of the particles of the desulfurizing agent such as limestone existing in the surroundings. When the amount of the melt is small, the viscosity of the adhered melt is high and the melt crosslinks the particles to adhere the particles to each other to form a lump. When the amount of melt increases, the viscosity of the melt adhering to the surface of the particles decreases, so that the particles are easily dispersed and lumps are difficult to form. Therefore, the melt amount of the molten ash is suitable as an index for predicting the fluidized state, is simple, and has excellent reliability. (2) Using the compounding ratio of the combustion ash obtained by the combustion of the fuel supplied to the fluidized bed combustion device and the desulfurizing agent, the ratio of each component of the standard oxide in the molten ash is calculated, and the molten ash melt is obtained. Since the amount is estimated, the versatility is excellent regardless of the type of fuel, the type of desulfurizing agent, and the compounding amount. (3) Use the phase diagram, thermodynamic calculation, refractory brick manufacturing furnace design software, etc. for the melt amount of molten ash produced within the prescribed temperature range in the thermodynamic equilibrium state by the standard oxides having the respective component ratios. Since it can be obtained by using a calculation method or the like, it is excellent in reliability and workability. (4) Since estimation is performed using standard oxides of molten elements,
It suffices to consider only the case of the thermodynamic equilibrium state without considering a complicated transient state, which simplifies the work of calculation and the like and is excellent in workability and can be generalized.

Here, as the fuel, coal, lignite, brown coal, bituminous coal, coke, petroleum coke, oil coke, oil sand, heavy oil, coal liquefaction residue, rubber, old tires, waste oil, general waste, general waste , Wood, carbide,
RDF and other carbides, wood chips, industrial waste, organic residues discharged from food factories and agriculture, sewage sludge, human waste treatment sludge, industrial wastewater treatment sludge, and mixtures thereof are used, and as combustion ash, The ash that remains after the fuel is burned is used. Examples of the desulfurizing agent include CaCO ₃ (or limestone), MgCO ₃ (or dolomite), CaO and C
a (OH) ₂ , K ₂ CO ₃ , aquatic wastes containing calcium such as shells, cement sludge and the like are used.

The molten element that constitutes the molten ash is S
i, Al, Ca, Mg, etc. are used, and combustion ash and desulfurizing agent are mixed and melted in a heating furnace to experimentally create molten ash, or molten ash actually generated in a fluidized bed combustion device. X and so on
It is specified by analysis by a line diffraction method or the like. The content of the molten element is determined by the fluorescent X of the fuel, combustion ash, and desulfurization agent.
It can be determined by quantitative analysis by a method such as a line analysis method. In addition, it is also possible to use the elements described in the certificate of performance such as fuel or combustion ash, desulfurization agent, etc. and the quantitative analysis results thereof.

As the standard oxide, among the oxides in each molten element, the most stable oxide that is naturally present is used. The converted content rate of the standard oxide can be obtained from the relationship between the analytical value of the molten element, the atomic weight of the molten element, and the molecular weight of the standard oxide.

In the component ratio calculating step, based on the compounding ratio in which the combustion ash and the desulfurizing agent are supplied per unit time, and the converted standard oxide content rate calculated in the component ratio calculating step, Component ratio of each standard oxide to 100% molten ash (wt%) so that the total of component ratios is 100%
To calculate. The mixture ratio of combustion ash is calculated in consideration of the amount of combustion ash obtained by burning the fuel supplied to the fluidized bed combustion device.

In the melting state estimating step, the amount of melt and the melting amount in a thermodynamic equilibrium state within a predetermined temperature range are calculated based on the pressure and each component ratio of the standard oxide calculated in the component ratio calculating process. The liquid generation start temperature and the like are estimated using means such as phase diagram, thermodynamic calculation, calculation using refractory brick manufacturing furnace design software, and the like. In addition, as the predetermined temperature range, a temperature range from a temperature at which molten ash starts melting to a maximum reached temperature of the fluidized bed combustion apparatus is used.

According to a second aspect of the present invention, there is provided a method for predicting a fluidized state in a fluidized bed combustion apparatus, wherein the fuel or a combustion ash obtained by burning the fuel, a desulfurizing agent and a flow improver are contained in the combustion ash. , The desulfurizing agent, from the content of the molten element constituting the molten ash produced by melting the flow improver,
The combustion ash, the desulfurization agent, a conversion content calculating step of calculating the conversion content of the standard oxide of the molten element of each of the flow improver, the combustion ash, the desulfurization agent, and the flow improver , Is a mixing ratio that is supplied per unit time, and based on the converted content of the standard oxide calculated in the converted content calculation step, based on the ratio of each component of the standard oxide in the molten ash Based on the component ratio calculating step to calculate, the respective component ratios calculated in the component ratio calculating step, and the pressure, a melt of the molten ash generated within a predetermined temperature range in a thermodynamic equilibrium state. And a melting state estimating step of estimating the amount. With this configuration, in addition to the operation described in claim 1, the following operation can be obtained. (1) When a good flow state cannot be predicted when only fuel and desulfurizing agent are supplied to the fluidized bed combustion device, the flow improver can be added to change the component ratio of the standard oxide in the molten ash. The degree of freedom can be increased.

Here, as the flow improver, Mg (OH) ₂ , Al ₂ O ₃ , Al (OH) which affects the amount of melt formed on the surface of the desulfurization agent and improves the flow state of the desulfurization agent. ) ₃ ,
Dolomite, MgO, Mg (CO ₃ ) ₂ or the like is used.
The fuel, the desulfurizing agent, the molten elements forming the molten ash, the standard oxide, the component ratio calculating step, the molten state estimating step, and the like are the same as those described in claim 1, and thus the description thereof will be omitted.

The invention according to claim 3 is the invention according to claim 1 or 2.
A method for predicting a fluidized state in a fluidized bed combustion apparatus according to claim 1, wherein the amount of melt estimated in the molten state estimation step, using a fusion control means, a fusion control step of approaching a preset reference value. It has a configuration including. With this configuration, the following action is obtained in addition to the action obtained in claim 1 or 2. (1) Since the melt control step is included, when the calculated melt amount is different from the set reference value of the melt amount, the melt control means is used to bring the melt closer to the reference value. Since the amount can be optimized, measures for improving the flow state and obtaining a normal operating state can be studied in advance.

Here, the melting control step is a step of bringing the melt amount close to a reference value within a preset temperature range by using the melting control means. As the melting control means, a means for changing the component ratio of the standard oxide of the melting element is used so that the melt amount of the molten ash approaches the reference value within the preset predetermined temperature range. The reference value is expressed as the relationship between the temperature and the melt amount within a predetermined temperature range. Further, the reference value can be used by updating or additionally registering the previous reference value when it is determined that the normal operating state of the fluidized bed combustion device is maintained. As a result, a new reference value can be obtained as the operating time is accumulated, and the range is widened, resulting in excellent workability.

The invention described in claim 4 is a method for predicting a fluidized state in a fluidized bed combustion apparatus according to claim 3,
The melting control means includes (a) a type of the desulfurizing agent, and (b)
The composition is such that any one or more of the blending amount of the desulfurizing agent, (c) the type of fuel, (d) the type of the flow improver, and (e) the blending amount of the flow improver is changed. ing. With this configuration, in addition to the effect obtained in claim 3,
The following actions are obtained. (1) Since various melting control means for controlling the melt amount by changing the type and blending amount of the desulfurization agent, the type of fuel, the type and blending amount of the flow improver, selection of the melting control means It has a wide width and excellent flexibility. (2) As the melting control means for changing the type of fuel, a mixture of a plurality of fuels of different types can be used, so that a fuel type that cannot be used due to poor flow or agglomeration is also mixed. It can be used as a fuel, and it is excellent in productivity and resource saving without impairing the time and cost required for purchasing fuel. (3) It has a simple melting control means for controlling the melt amount by changing the type and blending amount of the desulfurization agent, the type of fuel, the type and blending amount of the flow improver, and by using the melting control means. Since the flow state can be predicted in advance, it has excellent productivity.

Here, as the melting control means,
Any one or more of (a) type of desulfurizing agent, (b) amount of desulfurizing agent, (c) type of fuel, (d) type of fluidity improver, and (e) amount of fluidity improver are changed. Things are used. As the type of desulfurizing agent, the type of desulfurizing agent, the place of origin, etc. are used. A single type of desulfurizing agent may be used, or a plurality of types may be mixed and used. As the type of fuel, a fuel type, a production area, etc. are used. Similar to the desulfurizing agent, a single type of fuel may be used, or a plurality of types may be mixed and used. As the flow improver, Mg (OH) ₂ , MgO, Mg (CO ₃ ) ₂ , in order to increase the melt amount,
Dolomite or the like is used, and Al ₂ O ₃ , Al (OH) _3, or the like is used to increase the melt generation start temperature and decrease the melt amount. By increasing the blending amount of the flow improver, it is possible to remarkably increase or decrease the melt amount.

The invention according to claim 5 of the present invention is the method for predicting a fluidized state in a fluidized bed combustion apparatus according to any one of claims 1 to 4, wherein the standard oxide is Si.
It has a constitution of four components of O ₂ , Al ₂ O ₃ , CaO and MgO. With this configuration, in addition to the operation obtained in any one of claims 1 to 4, the following operation is obtained. (1) Gehlen found in molten ash that contains Si and Al and lowers the melting point of the desulfurization agent by interaction with Ca to melt
ite (Ca ₂ Al ₂ SiO ₇ ) and anorthete
The amount of melt such as (CaAl ₂ SiO ₈ ) can be calculated, and the effect of Mg that acts to increase the amount of melt of the molten ash can be predicted, which is excellent in reliability of fluid state prediction.

A method for operating a fluidized bed combustion apparatus according to a sixth aspect of the present invention is the optimum desulfurization obtained by the fluidized state predicting method in the fluidized bed combustion apparatus according to any one of the first to fifth aspects. Based on the type and blending amount of agent, the type of fuel, and the type and blending amount of flow improver, it has a configuration to determine the type and blending amount of desulfurizing agent, fuel and flow improver to be supplied to the fluidized bed combustion device. There is. With this configuration, the following effects can be obtained. (1) Since the types and blending amounts of the desulfurizing agent, the fuel, and the flow improver to be supplied to the fluidized bed combustor are determined based on the results obtained by the fluidized state prediction method, trial and error for improving the fluidized state is required Excellent workability and productivity without the need.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, more specific examples will be described. (Calculation of standard oxide conversion content) Blazeol coal or Nantun coal was used as fuel, limestone from Tsukumi was used as desulfurization agent, and Mg (OH) ₂ , Al (OH) ₃ , as flow improver,
The amount of molten ash in the fluidized bed combustor when any one of the dolomites was used was estimated. In the conversion content calculation step, first, a predetermined amount of fuel Blairsol coal and Nantun coal was sampled and adjusted to a particle size of about 6 mm or less, and the content was 450 to 600 in an air atmosphere below the combustion temperature of the fluidized bed combustor. It was heated at ℃ for about 72 hours to prepare combustion ash. Next, the composition of the produced combustion ash was analyzed by a fluorescent X-ray analysis method. The analysis results are shown in (Table 1).

[Table 1] From the component analysis results by the fluorescent X-ray analysis method shown in (Table 1), M, which is the molten element contained in the Blairsol charcoal
% content of MgO, which is the standard oxide of g (wt%)
Was calculated to be 0.60 wt% by (Mg analysis value) × (MgO molecular weight) / (Mg atomic weight). When other molten elements were calculated in the same manner, Si, Al, Ca
Of SiO ₂ , Al ₂ O ₃ and CaO, which are standard oxides of SiO ₂ , are converted into SiO ₂ : 55.61 wt%, Al ₂ O ₃ : 3:
It was 0.25 wt% and CaO: 0.54 wt%. Similarly, when the converted content rates of the standard oxides of Si, Al, Ca, and Mg, which are the melting elements contained in Nantun coal, were calculated in the same manner, SiO ₂ : 42.36 wt%, Al
₂ O ₃ : 31.64 wt%, CaO: 7.44 wt%, M
It was gO: 2.12 wt%. The compounds and numerical values shown in parentheses in (Table 1) are the standard oxides of each element and the converted content (wt%).

With respect to limestone as a desulfurizing agent, component analysis was also carried out by a fluorescent X-ray analysis method, and the converted content rates of standard oxides of molten elements Si, Al, Ca and Mg contained in limestone were determined. SiO ₂ : 0.1 wt%, Al _{2
O 3: 0.01wt%, CaO:} 53wt%, MgO:
It was 0.5 wt%.

Next, Mg (OH) ₂ as a flow improver
The converted content rate (wt%) of the standard oxide MgO was determined.
The component analysis results of Mg (OH) ₂ are shown in (Table 2).

[Table 2] From the component analysis results by the fluorescent X-ray analysis method shown in (Table 2), the converted content rate of the standard oxide MgO of the molten element contained in Mg (OH) ₂ was calculated to be 64.42.
It was wt%. Similarly, Al as a flow improver
The converted content rate of the standard oxide Al ₂ O ₃ of (OH) ₃ was calculated to be 95.2 wt%. Furthermore, the component analysis of dolomite as a flow improver was performed by using a fluorescent X-ray analysis method or the like. The analysis results are shown in (Table 2). From the results of the component analysis by the fluorescent X-ray analysis method shown in (Table 2), Si, Al, Ca, M which are the melting elements contained in dolomite
When the converted content of standard oxide of g was calculated,
₂ : 1.5 wt%, Al ₂ O ₃ : 0 wt%, CaO: 3
It was 2.9 wt% and MgO: 18.7 wt%. The compounds and numerical values shown in parentheses in (Table 2) are the standard oxides and the converted contents. The converted content rates (wt%) of the standard oxides SiO ₂ , Al ₂ O ₃ , CaO, and MgO calculated as described above are summarized in (Table 3).

[Table 3]

(Example 1, Example 2, Comparative Example 3) In a fluidized bed combustor in which Blazeol carbon was used as fuel, limestone from Tsukumi was used as a desulfurizing agent, and Mg (OH) ₂ was used as a flow improver. The amount of molten ash was estimated. In the component ratio calculation step, standard oxides SiO ₂ , Al calculated in the converted content rate calculation step based on the mixing ratio of combustion ash, desulfurization agent, and flow improver generated from the fuel supplied to the fluidized bed combustion device. By using the converted contents of ₂ O ₃ , CaO, and MgO, the component ratio (wt%) of each standard oxide of the molten ash composed of the molten elements contained in the combustion ash, the desulfurizing agent, and the flow improver is calculated. It was calculated. The mixing ratio of combustion ash and desulfurization agent is 7 wt% of ash content of fuel (Breasol charcoal).
%, And the Ca / S molar ratio was determined to be 3. As the desulfurizing agent, one having a particle diameter of 2 mm or less was used in order to improve the desulfurizing efficiency. The calculated mixing ratios of the combustion ash, the desulfurizing agent and the flow improver in Examples 1, 2 and Comparative Example 1 and the component ratios (wt) of standard oxides SiO ₂ , Al ₂ O ₃ , CaO and MgO. %) Is shown in (Table 4).

[Table 4]

In the molten state estimation step, the component ratios (wt%) of standard oxides SiO ₂ , Al ₂ O ₃ , CaO, and MgO, the pressure and oxygen concentration in the fluidized bed combustor, and the combustion temperature are determined. Using the refractory brick manufacturing furnace design software "FACT" (developer: Polytechnic Institute of Montreal, import agency: Equestrian Co., Ltd.), the amount of melt at each combustion temperature of molten ash in the standard state was calculated. It was calculated. The pressure and oxygen concentration in the fluidized bed combustor are 1.6 MPa (16 ata) and 3 vol%,
The temperature range of the combustion temperature was 1000 to 1500 ° C. The calculation result is shown in FIG. The horizontal axis of FIG. 1 represents the temperature, and the vertical axis represents the melt amount (wt%) in the molten ash. Here, the temperature range of the combustion temperature is preferably 1000 to 1500 ° C., and preferably 1100 to 1300 ° C., although it varies depending on the type of fluidized bed combustion device and the type of fuel. As the lower limit of the temperature range becomes lower than 1100 ° C, the molten ash tends not to generate a melt and it becomes difficult to compare the amounts of melt, and as the upper limit of the temperature range becomes higher than 1300 ° C, there is a large difference in the amount of melt. It is not preferable because it tends to be difficult to determine. In particular, it has been found that these tendencies are not preferable when the temperature is lower than 1000 ° C or higher than 1500 ° C. From FIG. 1, it can be seen that as the amount of Mg (OH) ₂ added as a flow improver increases,
It was found that the melt amount at 0 to 1400 ° C tends to increase. From this, it was estimated that Mg (OH) ₂ has a function of increasing the melt amount. In addition,
The fuel, the desulfurizing agent, and the flow improver were actually supplied to the 350 MW pressurized fluidized bed combustor at the compounding ratios shown in Examples 1, 2 and Comparative Example 1, and the pressure was 1.6 MPa and the temperature was 800 to 950 ° C.
When burned at, in Example 1 and Example 2,
In each case, a good combustion state was obtained, and no trouble due to poor flow was observed, whereas in Comparative Example 1, there was a trouble that the output was reduced. Upon investigation, it was due to the generation of lumps.

Example 3 and Comparative Example 2 Blazeol charcoal was used as the fuel, limestone from Tsukumi was used as the desulfurizing agent, and Al (OH) ₃ as the flow improver was used to remove molten ash in the fluidized bed combustor. The amount of melt was estimated. In the same manner as in Example 1, in the component ratio calculation step, the component ratio (wt%) of each standard oxide of the molten ash generated by the molten elements contained in the combustion ash, the desulfurizing agent and the flow improver was calculated. did. The mixing ratio of the combustion ash, the desulfurizing agent, and the flow improving agent in Example 3 and Comparative Example 2 and Si as the standard oxide
O ₂ , Al ₂ O ₃ , CaO, MgO composition ratio (wt%)
Are shown in (Table 4). Next, in the molten state estimation step,
SiO ₂ , Al ₂ O ₃ , CaO, MgO composition ratio (wt
%), The pressure and oxygen concentration in the fluidized bed combustor described in Example 1, and each factor of the combustion temperature are used to calculate with the refractory brick manufacturing furnace design software “FACT”, and each of the molten ash in the standard state is calculated. The melt volume at the combustion temperature was calculated. The result is shown in FIG. From FIG. 2, Al as a flow improver
As the amount of (OH) ₃ added increases, about 1200-1
It was found that the melt generation start temperature tends to rise as the melt amount at 300 ° C. decreases. As a result, Al (OH) ₂ raises the melt generation start temperature,
It was presumed that it had a function of reducing the melt volume. The fuel, the desulfurizing agent, and the flow improver were actually supplied to the 350 MW pressurized fluidized bed combustor at the compounding ratios shown in Example 3 and Comparative Example 2, and the pressure was 1.6 MPa and the temperature was 800 to 950 ° C.
In Example 3, a good combustion state was obtained, and no trouble due to poor flow was observed, whereas in Comparative Example 2, a problem of reduced output occurred. . Upon investigation, it was due to the generation of lumped fluid medium.

(Example 4, Comparative Example 3 and Comparative Example 4) Blazeol carbon was used as a fuel, limestone from Tsukumi was used as a desulfurizing agent, and dolomite CaMg (CO ₃ ) ₂ was used as a flow improver.
The amount of melt in the fluidized bed combustor in the case of using is estimated. In the component ratio calculation step, based on the mixing ratio of the combustion ash generated from the fuel supplied to the fluidized bed combustor, the desulfurizing agent, and the flow improving agent, depending on the molten element contained in the combustion ash, the desulfurizing agent, and the flow improving agent. The component ratio (wt%) of each standard oxide in the generated molten ash was calculated. The mixing ratio of combustion ash and desulfurization agent is 7 ash of fuel (Breasol coal).
%, and the total Ca / S molar ratio of the desulfurizing agent and the flow improver (dolomite) to the fuel was determined to be 6. The calculated mixing ratio of the combustion ash, the desulfurizing agent, and the flow improver in Example 4, Comparative Example 3, and Comparative Example 4 and SiO as the standard oxide
The component ratios (wt%) of ₂ , Al ₂ O ₃ , CaO and MgO are shown in (Table 4). Next, in the molten state estimation step, the component ratios (wt%) of SiO ₂ , Al ₂ O ₃ , CaO, and MgO that are standard oxides, the pressure and oxygen concentration in the fluidized bed combustor shown in Example 1, Using each factor of the combustion temperature, calculation was performed with the refractory brick manufacturing furnace design software "FACT", and the melt amount of the molten ash at each combustion temperature in the standard state was calculated. The calculation result is shown in FIG. As shown in FIG. 3, as the amount of dolomite added as a flow improver increases,
It was found that the melt amount at 50 to 1350 ° C. tends to remarkably increase. From this, it was estimated that dolomite has a function of increasing the melt amount. The fuel, the desulfurizing agent, and the flow improver were actually supplied to the 350 MW pressurized fluidized bed combustor at the compounding ratios shown in Example 4, Comparative Example 3, and Comparative Example 4, and the pressure was 1.6 MPa and the temperature was 800 to 95.
When burned at 0 ° C., in Example 4, a good combustion state was obtained, and no trouble due to poor flowability was observed, whereas in Comparative Example 3 and Comparative Example 4, both There was a problem that the output decreased. Upon investigation, it was due to the generation of lumped fluid medium.

(Examples 5, 6, and 7) Fluidized bed combustion apparatus in the case of using Nantun coal as a fuel, limestone from Tsukumi as a desulfurizing agent, and Mg (OH) ₂ as a flow improver The amount of melt was estimated. In the component ratio calculation step, based on the mixing ratio of the combustion ash generated from the fuel supplied to the fluidized bed combustor, the desulfurizing agent, the flow improving agent, depending on the molten element contained in the combustion ash, the desulfurizing agent and the flow improving agent. The component ratio (wt%) of each standard oxide in the generated molten ash was calculated. The mixing ratio of the combustion ash and the desulfurizing agent was determined by setting the ash content of the fuel (Nantun Coal) to 7 wt% and the Ca / S molar ratio to 3. The calculated mixing ratios of the combustion ash, the desulfurizing agent and the flow improver in Examples 5, 6 and 7 and the standard oxides SiO ₂ , Al ₂ O ₃ and Ca.
The component ratio (wt%) of O and MgO is shown in (Table 5).

[Table 5] Next, in the molten state estimation step, SiO ₂ , Al
Component ratio of ₂ O ₃ , CaO, MgO (wt%), Example 1
Using the factors of pressure, oxygen concentration and combustion temperature in the fluidized bed combustor shown in, calculated with the refractory brick manufacturing furnace design software "FACT", and the melt amount at each combustion temperature of the molten ash in the standard state. Was calculated. The calculation result is shown in FIG. As shown in FIG. 4, as the amount of Mg (OH) ₂ added as a flow improver increased, the amount of about 1150 to 150
It was found that the melt amount at 1350 ° C. tends to increase. Further, the melt amount at about 1150 to 1350 ° C. of Example 5 using Nantun coal (without addition of a flow improver) was compared with that of Comparative Example 1 using Blairsol coal (without addition of a flow improver). Then, it was confirmed that there were many. From this, it was found that the amount of molten ash generated and the amount of melt differed depending on the fuel type. The fuel, the desulfurizing agent, and the flow improver were actually supplied to the 350 MW pressurized fluidized bed combustor at the compounding ratios shown in Examples 5, 6 and 7 to obtain a pressure of 1.6.
When combusted at MPa and a temperature of 800 to 950 ° C., good combustion was obtained in all cases, and no troubles due to poor flow were observed. From this, it was found that Nantonun coal, unlike Blairsol coal, can obtain good combustion and flow conditions without using a flow improver.

(Comparative Examples 5 and 6) The amount of melt in the fluidized bed combustor in the case of using Nantun coal as fuel, limestone from Tsukumi as desulfurizing agent and Al (OH) ₃ as flow improver An estimate was made. In the component ratio calculation step, based on the mixing ratio of the combustion ash generated from the fuel supplied to the fluidized bed combustor, the desulfurizing agent, the flow improving agent, depending on the molten element contained in the combustion ash, the desulfurizing agent and the flow improving agent. The component ratio (wt%) of each standard oxide in the generated molten ash was calculated. The mixing ratio of the combustion ash and the desulfurizing agent was determined by setting the ash content of the fuel (Nantun Coal) to 7 wt% and the Ca / S molar ratio to 3. The calculated mixing ratios of the combustion ash, the desulfurizing agent and the flow improver in Comparative Examples 5 and 6 and the component ratios (wt) of standard oxides SiO ₂ , Al ₂ O ₃ , CaO and MgO.
%) Is shown in (Table 5). Next, in the molten state estimation step, the composition ratios (wt%) of SiO ₂ , Al ₂ O ₃ , CaO, and MgO, the pressure and oxygen concentration in the fluidized bed combustor shown in Example 1, and each factor of combustion temperature. Was calculated by the refractory brick manufacturing furnace design software “FACT”, and the amount of melt at each combustion temperature of the molten ash in the standard state was calculated.
The calculation result is shown in FIG. From FIG. 5, it can be seen that as the addition amount of Al (OH) ₃ as a flow improver increases,
It was found that the melt amount at ˜1300 ° C. tends to decrease. However, the increase in melt formation initiation temperature, which was observed in the case of Blairsol charcoal, was not confirmed. The fuel, the desulfurizing agent, and the flow improver were actually supplied to the 350 MW pressurized fluidized bed combustor at the compounding ratios shown in Comparative Examples 5 and 6 and burned at a pressure of 1.6 MPa and a temperature of 800 to 950 ° C. However, it was confirmed that the output decreased in all cases. Upon investigation, it was due to the generation of lumps.

(Comparative Example 7, Comparative Example 8 and Comparative Example 9) Melting of molten ash in a fluidized bed combustor in the case of using Nantun coal as fuel, limestone from Tsukumi as desulfurizing agent and dolomite as flow improver The liquid volume was estimated. In the same manner as described in Example 4, in the component ratio calculation step, the combustion ash and the desulfurization are produced based on the mixing ratio of the combustion ash generated from the fuel supplied to the fluidized bed combustion device, the desulfurizing agent, and the flow improver. The component ratio (wt%) of each standard oxide of the molten ash contained in the agent and the flow improver and generated by the molten element was calculated.
The mixture ratio of combustion ash and desulfurization agent is 7 wt% of ash content of fuel (Nantun Coal), and desulfurization agent and flow improver (dolomite).
And the Ca / S molar ratio between the fuel and the fuel was determined as 6.
The calculated mixing ratio of the combustion ash, the desulfurizing agent, and the flow improver in Comparative Examples 7, 8, and 9 and the component ratio of standard oxides SiO ₂ , Al ₂ O ₃ , CaO, and MgO (wt.
%) Is shown in (Table 3). Next, in the molten state estimation step, the composition ratios (wt%) of SiO ₂ , Al ₂ O ₃ , CaO, and MgO, the pressure and oxygen concentration in the fluidized bed combustor shown in Example 1, and the combustion temperature are set as follows. It was used to calculate with the refractory brick manufacturing furnace design software “FACT”, and the amount of melt at each combustion temperature of the molten ash in the standard state was calculated. The calculation result is shown in FIG. As shown in FIG. 6, as the amount of dolomite added as a flow improver increases, the amount of about 1000-13 increases.
It was found that the melt amount at 50 ° C. tends to increase. The fuel, the desulfurizing agent, and the flow improver were actually supplied to the 350 MW pressurized fluidized bed combustor at the compounding ratios shown in Comparative Examples 7, 8, and 9, and the pressure was 1.6 MPa and the temperature was 80%.
When combusted at 0 to 950 ° C., it was confirmed that the output decreased in all cases. Upon investigation, it was due to the generation of lumps.

As described above with reference to Examples and Comparative Examples, within the predetermined temperature range estimated in the molten state estimation step based on the results calculated in the converted content rate calculation step and the component ratio calculation step. It was clarified that there is a correlation between the amount of melt and the actual operating state of the fluidized bed combustion device (whether stable operation is possible). Therefore, it was clarified that the fluid state in the fluidized bed combustor can be predicted by estimating the melt amount by the blending ratio of the combustion ash, the desulfurizing agent and the flow improver. It was also clarified that the amount of melt and the operating condition of the fluidized bed combustor may change when the fuel type changes. Furthermore, the melt amount tends to increase as the addition amount of dolomite, Mg (OH) ₂ etc. as a flow improver increases, and the melt amount increases as the addition amount of Al (OH) ₃ etc. increases. It was clarified that the melt formation start temperature tends to increase with the decrease. Therefore, by changing the type of fuel supplied to the fluidized bed combustor, mixing two or more types of fuel, and changing the type and addition amount of the flow improver, the melt amount and melt generation start temperature can be controlled. It was clarified that control was possible and the operating condition of the fluidized bed combustor could be improved. From this, (a) the type of desulfurizing agent (such as changing the type of desulfurizing agent from limestone to dolomite), (b) the blending amount of desulfurizing agent, (c) the type of fuel (including mixing a plurality of fuels ), (D) Mg (O
H) ₂ , Mg (OH) ₂ , dolomite, etc. The kind of flow improver, and (e) the compounding amount of any one or more of the flow improvers are used as a melting control means, and a standard oxide of a molten element is used. By using the melting control process that changes the component ratio of, and brings the melt amount close to the reference value within the preset temperature range, it is possible to control the melt amount and the melt generation start temperature. It has become clear that the operating condition of the device can be kept good. Further, when operating the fluidized bed combustion apparatus, the relationship between the temperature and the melt amount shown in Examples 1 to 7 is used as a reference value, and the melt amount of the molten ash generated in a predetermined temperature range is Estimate in advance that the fluid state in the fluidized bed combustion device will be good by determining the type and amount of desulfurizing agent, the type of fuel, and the type and amount of flow improver so as to approach the standard value. It became clear that

[0033]

As described above, according to the method for predicting a fluidized state in a fluidized bed combustion apparatus of the present invention and the method for operating a fluidized bed combustion apparatus using the same, the following advantageous effects are obtained. According to the invention of claim 1, (1) the melt of molten ash obtained by melting the combustion ash adheres to the surface of the particles of the desulfurizing agent such as limestone existing in the surroundings. When the amount of the melt is small, the viscosity of the adhered melt is high and the melt crosslinks the particles to adhere the particles to each other to form a lump. When the amount of melt increases, the viscosity of the melt adhering to the surface of the particles decreases, so that the particles are easily dispersed and lumps are difficult to form. Therefore, the melt amount of molten ash is suitable as an index for predicting the fluidized state, and it is possible to provide a simple and highly reliable fluidized state combustion method in a fluidized bed combustion apparatus. (2) Using the compounding ratio of the combustion ash obtained by the combustion of the fuel supplied to the fluidized bed combustion device and the desulfurizing agent, the ratio of each component of the standard oxide in the molten ash is calculated, and the molten ash melt is obtained. Since the amount is estimated, it is possible to provide a method for predicting a fluidized state in a fluidized bed combustor which is excellent in versatility regardless of the type of fuel, the type of desulfurizing agent and the blending amount. (3) The melt amount of the molten ash produced by the standard oxide having each component ratio within the predetermined temperature range in the thermodynamic equilibrium state is determined by means such as a phase diagram or FACT etc. Since it can be obtained by using the method, it is possible to provide a method for predicting a fluidized state in a fluidized bed combustion apparatus which is excellent in reliability and workability. (4) Since estimation is performed using standard oxides of molten elements,
It is only necessary to consider the case of the thermodynamic equilibrium state without considering the complicated transient state, which simplifies the work such as calculation and is excellent in workability and can be generalized. A method can be provided.

According to the invention of claim 2, claim 1
In addition to the effect of (1), when a good fluid state cannot be predicted when only fuel and desulfurizing agent are supplied to the fluidized bed combustor, by adding a flow improver, the ratio of standard oxide components in molten ash can be increased. It is possible to provide a method for predicting a fluidized state in a fluidized bed combustor with high flexibility.

According to the invention of claim 3, claim 1
Or, in addition to the effect of 2, since (1) the melt control step is included, when the calculated melt amount is different from the set reference value of the melt amount, the melt control means is used. Since it is possible to optimize the melt volume by approaching the standard value by providing a method for predicting the fluid state in a fluidized bed combustion device, it is possible to study in advance measures to improve the fluid state and obtain a normal operating state. can do.

According to the invention of claim 4, claim 3
In addition to the effect of (1) since it has various melting control means for controlling the melt amount by changing the type and amount of desulfurization agent, the type of fuel, the type and amount of flow improver, It is possible to provide a method for predicting a fluidized state in a fluidized bed combustion apparatus, which has a wide range of choices for the melting control means and is excellent in flexibility. (2) As the melting control means for changing the type of fuel, a mixture of a plurality of fuels of different types can be used, so that a fuel type that cannot be used due to poor flow or agglomeration is also mixed. It is possible to provide a method for predicting a fluidized state in a fluidized bed combustor that is excellent in productivity and resource saving without impairing the time and cost required for fuel purchase. (3) It has a simple melting control means for controlling the melt amount by changing the type and blending amount of the desulfurization agent, the type of fuel, the type and blending amount of the flow improver, and by using the melting control means. Since the fluidized state can be predicted in advance, it is possible to provide a fluidized state predicting method in a fluidized bed combustion apparatus having excellent productivity.

According to the invention of claim 5, claim 1
In addition to the effect of any one of 1 to 4, (1) Si and Al
Gehlenite (Ca ₂ A) found in molten ash that contains helium and lowers the melting point of the desulfurization agent by interaction with Ca
l ₂ SiO ₇ ) and anorthite (CaAl ₂ Si
The amount of melt such as O ₈ ) can be calculated, and
It is possible to predict the effect of Mg that functions to increase the amount of molten ash, and it is possible to provide a highly reliable fluidized state prediction method in a fluidized bed combustion apparatus.

According to the sixth aspect of the invention, (1) based on the results obtained by the fluidized state prediction method, the types and blending amounts of the desulfurizing agent, the fuel and the fluidity improving agent to be supplied to the fluidized bed combustor are determined. Since it is determined, it is possible to provide a method of operating a fluidized bed combustion device using a fluidized state prediction method in a fluidized bed combustion device that is excellent in workability and productivity without requiring trial and error to improve the fluidized state. .

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between temperature and melt volume in Examples 1, 2 and Comparative Example 1.

FIG. 2 is a diagram showing a relationship between temperature and melt amount in Example 3, Comparative Example 1, and Comparative Example 2.

FIG. 3 is a graph showing the relationship between temperature and melt volume in Example 4, Comparative Example 3, and Comparative Example 4.

FIG. 4 is a diagram showing the relationship between the temperature and the melt amount in Examples 5, 6 and 7.

FIG. 5 is a graph showing the relationship between the temperature and the melt amount in Example 5, Comparative Example 5, and Comparative Example 6.

FIG. 6 is a diagram showing the relationship between the temperature and the melt amount in Comparative Examples 7, 8 and 9.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F27D 19/00 F23C 11/02 304 (72) Inventor Satoshi Nakajima 2-chome Watanabe-dori, Chuo-ku, Fukuoka-shi, Fukuoka No. 82 Inside the thermal power department of Kyushu Electric Power Co., Inc. (72) Yutaka Mizumachi, No. 1 Nagahama-cho, Kanda-cho, Kyoto-gun, Fukuoka Prefecture Kyushu Electric Power Co., Inc. At Kanda Power Station (72) No. 1 Toshiharu Katabuchi, Nagahama-cho, Kanda-cho, Fukuoka-gun Kyushu Electric Power Co., Inc. Kanda Power Station (72) Inventor Hiroki Katoda 1-1, Nagahamacho, Kanda-cho, Kyoto-gun, Fukuoka Prefecture Kyushu Electric Power Co., Inc. Kanda Power Station (72) Inventor, Ryuji Uno 1, Nagahama-cho, Kanda-cho, Fukuoka Prefecture No. 1 Kyushu Electric Power Co., Inc. Kanda Power Plant (72) Inventor Yukio Imaizumi 2 1-47 Shiobara Minami-ku, Fukuoka City Fukuoka Prefecture Kyushu Electric Power Co., Inc. Ceremony Company Research Institute (72) Inventor Hiroki Kamakura 2-47 Shiobara, Minami-ku, Fukuoka, Fukuoka Prefecture Kyushu Electric Power Co., Inc. Research Institute (72) Inventor Tatsuro Harada, Chuo-ku, Fukuoka City 17 17 No. 8 West Japan Environmental Energy Co., Ltd. (72) Inventor Koho Sugino 1-17-8 Shirokane, Chuo-ku, Fukuoka-shi, Fukuoka Prefecture West Japan Environmental Energy Co., Ltd. (72) Inventor Tomoyuki Koyanagi 1 Platinum, Chuo-ku, Fukuoka-shi, Fukuoka C-No. 17-8 West Japan Environmental Energy Co., Ltd. F term (reference) 3K062 AA11 AB03 BA01 DB02 DB05 3K064 AA02 AA20 AB03 AD08 AE01 AF03 4G070 AA01 BB32 CA16 CB25 CC02 CC03 CC11 DA21 4K046 HA07 HA11 LA01 4K056 AA20 FAA19 CA12 CA12 CA12 CA12

Claims (6)

[Claims] 1. The content of the molten element contained in the fuel or the combustion ash obtained by burning the fuel, and the combustion ash contained in each of the desulfurization agents and the molten ash that is formed by melting the desulfurization agent , The combustion ash, a conversion content calculating step of calculating the conversion content of the standard oxide of the molten element of each of the desulfurization agent, the combustion ash, and the desulfurization agent, the composition is supplied per unit time A ratio, a component ratio calculation step of calculating each component ratio of the standard oxide in the molten ash, based on the converted content rate of the standard oxide calculated in the converted content rate calculation step, and the component Each component ratio calculated in the ratio calculation step,
A fluidized bed combustion apparatus, which comprises: based on the pressure, a molten state estimation step of estimating the amount of molten ash in the thermodynamic equilibrium state within a predetermined temperature range. Method for predicting fluid state in Japan. 2. A molten ash which is contained in each of a fuel or combustion ash obtained by burning the fuel, a desulfurizing agent and a flow improving agent, and which is produced by melting the combustion ash, the desulfurizing agent and the flow improving agent. From the content of the molten element that constitutes the combustion ash,
The desulfurization agent, a conversion content calculation step of calculating the conversion content of the standard oxide of the molten element of each of the flow improver, the combustion ash, the desulfurization agent, and the flow improver, unit time Based on the compounding ratio supplied around, and the reduced content of the standard oxide calculated in the reduced content calculation step, a component ratio for calculating each component ratio of the standard oxide in the molten ash. A calculation step, and each component ratio calculated in the component ratio calculation step,
A fluidized bed combustion apparatus, which comprises: based on the pressure, a molten state estimation step of estimating the amount of molten ash in the thermodynamic equilibrium state within a predetermined temperature range. Method for predicting fluid state in Japan. 3. A melting control step for bringing the melt amount estimated in the melting state estimation step closer to a preset reference value by using a melting control means. The fluidized state prediction method in the fluidized bed combustion apparatus according to 1 or 2. 4. The melting control means comprises: (a) type of the desulfurizing agent, (b) blending amount of the desulfurizing agent, (c) type of fuel, (d) type of flow improver, (e) ) A method of predicting a fluidized state in a fluidized bed combustion apparatus according to claim 3, wherein any one or more of the blending amounts of the fluidity improver is changed. 5. The standard oxide is SiO ₂ , Al
The fluidized state predicting method for a fluidized bed combustion apparatus according to claim 1, wherein the fluidized state combustion apparatus comprises four components of ₂ O ₃ , CaO, and MgO. 6. An optimum desulfurizing agent type and blending amount, a fuel type, and a flow improving agent type obtained by the fluidized state predicting method in the fluidized bed combustion apparatus according to any one of claims 1 to 5. A method for operating a fluidized bed combustion device, characterized in that the type and amount of desulfurizing agent, fuel, and flow improver to be supplied to the fluidized bed combustion device are determined based on the amount and blending amount.