CN106352315B - Method for operating boiler and boiler plant - Google Patents
Method for operating boiler and boiler plant Download PDFInfo
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- CN106352315B CN106352315B CN201610245260.4A CN201610245260A CN106352315B CN 106352315 B CN106352315 B CN 106352315B CN 201610245260 A CN201610245260 A CN 201610245260A CN 106352315 B CN106352315 B CN 106352315B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B1/00—Methods of steam generation characterised by form of heating method
- F22B1/22—Methods of steam generation characterised by form of heating method using combustion under pressure substantially exceeding atmospheric pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
- F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K3/00—Feeding or distributing of lump or pulverulent fuel to combustion apparatus
- F23K3/16—Over-feed arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
- F23L1/00—Passages or apertures for delivering primary air for combustion
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Abstract
The invention aims to provide a boiler operation method and a boiler plant which can inhibit the reduction of the heat storage rate of a hearth. The present invention is a method for operating a boiler in which a plurality of solid fuels are mixed and burned, the method comprising: obtaining the content of ash in the plurality of solid fuels and the content of at least 1 hydrous mineral in the ash; and determining a mixing ratio of the plurality of types of solid fuels such that the content of the at least 1 type of hydrous mineral in the ash of the entire mixture of the plurality of types of solid fuels becomes equal to or less than a reference value, based on the content of the ash and the content of the at least 1 type of hydrous mineral of each of the plurality of types of solid fuels obtained in the obtaining step. The at least 1 hydrous mineral may be kaolin or gypsum. The reference value is preferably 40% by mass.
Description
Technical Field
The present invention relates to a method of operating a boiler and a boiler plant.
Background
The boiler includes a furnace (japanese-language: burner) for burning a solid fuel by a burner or the like, and a plurality of heat transfer tubes arranged in the furnace in the vertical direction for performing heat exchange. The heat transfer pipe is composed of a lower heat transfer part and an upper heat transfer part, the lower heat transfer part is provided with a primary heater, a primary reheater and an economizer which are arranged at the lower part of the furnace chamber, and the upper heat transfer part is provided with a secondary heater, a tertiary heater, a final heater and a secondary reheater which are arranged at the upper part of the furnace chamber.
In such a boiler, for example, a pulverized coal boiler using coal as a solid fuel, ash in combustion gas generated by combustion of coal may adhere to the wall of a furnace and slag (sludging) and fouling (fouling) of a heat transfer pipe, and an ash adhesion layer may be formed. When such adhesion of ash occurs, the heat storage rate on the heat transfer surface of the heat transfer pipe tends to be greatly reduced. Further, when ash (slag) attached to the furnace wall is excessively increased, the ash may fall from the furnace wall or the like, causing a large variation in the furnace internal pressure, damage to the heat transfer pipe, and blockage of the gas flow path.
In particular, since the upper heat transfer portion has a structure in which combustion gas flows between heat transfer tubes arranged at a narrower interval than the lower heat transfer portion to exchange heat, if ash adheres to the upper heat transfer portion, a large variation in the furnace internal pressure and a blockage in the gas flow passage tend to occur, which hinders stable operation of the boiler. In addition, since the temperature near the furnace wall is increased near the burner by the radiant heat of the combustion flame of the fine coal, ash is likely to melt and adhere to the heat transfer tube at a relatively low temperature, and the heat storage rate of the furnace is likely to decrease.
Therefore, a method of operating a boiler has been proposed in which the possibility of ash adhesion is expressed as an index and ash adhesion is suppressed based on the index (japanese patent No. 5342355). In this conventional operation method, slag, which is a component adhering to the furnace wall and the heat transfer tube group, is focused, and the mixing ratio of the plurality of solid fuels is determined based on the slag ratio calculated for each solid fuel and the composition of the ash component. Specifically, the conventional boiler operation method determines a reference value of the slag ratio so as to reduce the ash adhesion rate, and determines a mixing ratio of the plurality of types of solid fuels so as to reduce the slag ratio to the reference value or less, thereby suppressing the adhesion of ash.
However, in the above-described conventional boiler operation method, the heat storage rate in the furnace may be lowered regardless of whether the adhesion of ash is suppressed. Therefore, a new method for operating a boiler that can suppress a decrease in the heat storage rate in the furnace is desired.
Documents of the prior art
Patent document
Patent document 1: japanese patent No. 5342355
Disclosure of Invention
Technical problem to be solved by the invention
The present invention has been made in view of the above circumstances, and an object thereof is to provide a boiler operation method and a boiler plant that can suppress a decrease in the heat storage rate of a furnace.
Means for solving the problems
The present inventors have conducted intensive studies and, as a result: when the ash deposits to the same extent, the reduction in the heat storage rate of the furnace is likely to occur when a solid fuel having a large content of water-containing minerals is used, and therefore attention is paid to the content of water-containing minerals in the ash in the whole mixture of a plurality of solid fuels. The results show that: the ash adhering layer is thermally insulated by the adhesion of porous ash resulting from the release of crystal water from the water-containing mineral, and the heat storage rate of the furnace is thereby reduced. Furthermore, the present inventors have found that: the present inventors have found that a boiler can be stably operated in order to suppress a decrease in the furnace heat storage rate by determining the mixing ratio of a plurality of types of solid fuels so that the content of the water-containing minerals is equal to or less than a reference value, and have completed the present invention.
That is, the present invention made in order to solve the above-mentioned problems is a method for operating a boiler in which a plurality of solid fuels are mixed and burned, the method comprising: obtaining the content of ash in the plurality of solid fuels and the content of at least 1 hydrous mineral in the ash; and determining a mixing ratio of the plurality of types of solid fuels such that the content of the at least 1 type of hydrous mineral in the ash of the entire mixture of the plurality of types of solid fuels becomes equal to or less than a reference value, based on the content of the ash and the content of the at least 1 type of hydrous mineral of each of the plurality of types of solid fuels obtained in the obtaining step.
In this method for operating a boiler, the mixing ratio of the plurality of types of solid fuels is determined so that the content of the hydrous minerals becomes equal to or less than the reference value, and therefore, the adhesion of porous ash due to the release of crystal water from the hydrous minerals can be suppressed. This reduces the adiabatic property of the adhering ash, and thus the operating method of the boiler can suppress a reduction in the heat storage rate of the furnace.
The at least 1 hydrous mineral may be kaolin or gypsum. Kaolin and gypsum account for a large proportion of hydrous minerals contained in solid fuels used in boilers, and are likely to cause a decrease in the heat storage rate of the furnace. Therefore, by using kaolin or gypsum as the at least 1 hydrous mineral, it is possible to more reliably suppress a decrease in the heat storage rate of the furnace.
The reference value is preferably 40% by mass. By setting the reference value to 40 mass% in this way, it is possible to more reliably suppress a decrease in the furnace heat storage rate.
The solid fuel may be coal. In a boiler using coal as a solid fuel, the heat storage rate in the furnace chamber is particularly liable to decrease. Therefore, the boiler operation method can be suitably used, which can suppress a decrease in the furnace heat storage rate.
Therefore, this method for operating a boiler is suitable for use in thermal power plant facilities using boiler facilities using coal as a solid fuel.
Another invention made to solve the above problems is a boiler plant for mixing and combusting a plurality of types of solid fuels, the boiler plant comprising: a plurality of supply mechanisms for supplying the plurality of types of solid fuels, respectively; a mixing mechanism for mixing the plurality of types of solid fuels supplied from the plurality of supply mechanisms; a pulverizing mechanism for pulverizing the solid fuel mixed by the mixing mechanism; a boiler for burning the solid fuel pulverized by the pulverizing mechanism; a determining means for determining a mixing ratio of the plurality of types of solid fuels such that the content of the at least 1 type of hydrous mineral in the ash of the whole mixture of the plurality of types of solid fuels becomes equal to or less than a reference value, based on the content of the ash of each of the plurality of types of solid fuels and the content of the at least 1 type of hydrous mineral in the ash; and an adjusting means for adjusting the supply amount of each of the plurality of types of solid fuels introduced from the supply means to the mixing means in accordance with the mixing ratio of the plurality of types of solid fuels determined by the determining means.
The boiler plant adjusts the mixing ratio of the plurality of solid fuels so that the content of the at least 1 hydrous mineral in the ash of the whole mixture of the plurality of solid fuels is equal to or less than a reference value, and supplies the solid fuels to the boiler. Therefore, the boiler plant is easy to stably operate because the heat storage rate of the furnace is not easy to reduce.
Here, "hydrous mineral" means: a mineral which contains water molecules or hydroxyl groups (OH) as components in the crystal structure and has a dehydration start temperature of 1000 ℃ or lower. In addition, "kaolin" means: in a group of clay mineralsKaolinite, nacrite and dickite are collectively called, and the chemical component is Al2Si2O5(OH)4The mineral is shown. "Gypsum" refers to the chemical composition as CaSO4·2H2And O represents a mineral.
Effects of the invention
As described above, the method for operating a boiler and the boiler plant according to the present invention can suppress a decrease in the heat storage rate of the furnace.
Drawings
FIG. 1 is a schematic diagram of a boiler plant showing one embodiment of the present invention.
Fig. 2 is a flowchart showing steps of a method for operating a boiler according to an embodiment of the present invention.
FIG. 3 is a graph showing the relationship between the kaolin content and the heat storage rate in the furnace.
Detailed Description
Hereinafter, embodiments of the boiler operation method and the boiler facility according to the present invention will be described with reference to a thermal power plant facility.
The thermal power plant facility includes the boiler facility, a steam turbine generator facility, and a condensed water supply facility.
< boiler plant >
The boiler plant shown in fig. 1 is a boiler plant in which a plurality of solid fuels are mixed and burned. The boiler plant comprises a hopper 1, a mixer 2, a pulverizer 3, a boiler 4, a processor 5, and a supply amount adjusting device 6.
(Bunker)
The hopper 1 is a mechanism for supplying solid fuel, and the boiler facility includes the hoppers 1 for supplying a plurality of types of solid fuel. Although fig. 1 shows a case where 2 hoppers 1 for supplying 2 types of solid fuels are provided, 3 or more types of solid fuels may be provided. In this case, the boiler plant is provided with the same number of hoppers 1 as the number of types of solid fuel.
The hopper 1 has a storage tank for storing the solid fuel, and the solid fuel can be taken out by dropping the solid fuel from a funnel-shaped opening of an open bottom type located at the bottom of the storage tank.
(mixing machines)
The mixer 2 is a mechanism for mixing the solid fuel supplied from the hopper 1. As the mixer 2, for example, a known drum mixer (dry mixer) or the like can be used.
(crushing machine)
The pulverizer 3 is a mechanism for pulverizing the solid fuel mixed by the mixer 2. As the pulverizer 3, a known vertical rolling mill (roll mill) or the like can be used.
The particle size of the solid fuel after pulverization is not particularly limited, and for example, the solid fuel may be pulverized so that the proportion of the solid fuel having a particle size of 75 μm or less is 75% or more and 90% or less.
(boiler)
The boiler 4 burns the solid fuel pulverized by the pulverizer 3. The boiler 4 mainly includes a burner 7, a furnace, a heat transfer pipe, and a chimney. The boiler 4 burns solid fuel blown together with air in a furnace by a burner 7, and performs heat exchange by a plurality of heat transfer tubes arranged in the vertical direction in the furnace. The water supplied to the heat transfer pipe by the heat exchange is heated and pressurized to generate steam. In addition, the combustion gas thus generated by combustion is discharged from the chimney.
The heat transfer pipe is appropriately configured according to the temperature and pressure of the required steam, and may be configured, for example, by a lower heat transfer part including a primary heater, a primary reheater and an economizer arranged in the lower part of the furnace, and an upper heat transfer part including a secondary heater, a tertiary heater, a final heater and a secondary reheater arranged in the upper part of the furnace. The lower heat transfer portion mainly preheats the feed water supplied to the boiler 4, and the upper heat transfer portion mainly generates high-temperature and high-pressure steam. The reheater reheats steam running in the steam turbine or the like to produce steam running in the reheat cycle turbine. In addition, the economizer preheats the feed water of the boiler 4 with the heat of the discharged combustion gas.
(processor)
The processor 5 is: and a means for determining the mixing ratio of the plurality of solid fuels so that the content of the kaolin in the ash of the entire mixture of the plurality of solid fuels is equal to or less than a reference value, based on the content of the ash of each of the plurality of solid fuels and the content of the kaolin in the ash.
The processor 5 calculates the mixing ratio of the plurality of types of solid fuels in a mixing ratio determination step (S2) of a boiler operation method described later. Further, the processor 5 controls the supply amount adjusting device 6 according to the calculated mixture ratio.
(supply amount adjusting device)
The supply amount adjusting device 6 is: and a mechanism for adjusting the respective supply amounts of the plurality of types of solid fuels introduced from the hopper 1 to the mixer 2 in accordance with the mixing ratio of the plurality of types of solid fuels determined by the processor 5. That is, the boiler plant includes 1 supply amount adjusting device 6 for each pipe connected to the mixer 2 from each hopper 1 having the same number as the types of the solid fuels, and the total number of the supply amount adjusting devices is the same as the types of the solid fuels. The supply amount adjusting device 6 is not particularly limited, and for example, a chain conveyor (chain conveyor) that transports the solid fuel from the hopper 1 to the mixer 2 may be used. At this time, the supply amount is adjusted by adjusting the moving speed of the conveyor.
< method for operating boiler >
Fig. 2 shows a method for operating a boiler using the boiler device. This method for operating a boiler is a method for operating a boiler in which a plurality of solid fuels are mixed and burned. The method for operating a boiler comprises: a step (S1) for obtaining the content of ash in the plurality of solid fuels and the content of kaolin, which is a water-containing mineral in the ash; a step (S2) of determining a mixing ratio of the plurality of types of solid fuels such that the content of the kaolin in the ash of the entire mixture of the plurality of types of solid fuels becomes equal to or less than a reference value, based on the content of the ash and the content of the kaolin of each of the plurality of types of solid fuels obtained in the obtaining step; and a step (S3) for mixing the plurality of types of solid fuels and supplying the mixed solid fuels to the furnace in accordance with the determined mixing ratio.
The solid fuel used in the method of operating a boiler is not particularly limited as long as it is a fuel used in the boiler, and examples thereof include coal, sludge carbide, and biomass fuel. Among them, coal which generates a large amount of heat and is suitable for use in thermal power plant facilities and the like is preferable.
The kind of the coal is not particularly limited. In this method for operating a boiler, the mixing ratio of the plurality of types of solid fuels is determined so that the content of the hydrous minerals in the ash becomes equal to or less than the reference value, and therefore, the adhesion of porous ash due to the release of crystal water from the hydrous minerals can be suppressed. Therefore, even coal containing a relatively large amount of crystal water can be mixed. Examples of the coal containing a relatively large amount of crystal water include anthracite, bituminous coal, sub-bituminous coal, lignite, high silica coal, and high calcium coal.
(content obtaining step)
In the content rate obtaining step (S1), the content rate of ash and the content rate of kaolin in the ash of each of the plurality of solid fuels are obtained.
The method for measuring the ash content of each solid fuel is not particularly limited, and for example, a method based on JIS-M-8812: 2006.
Kaolin is one of hydrous minerals, and the content of kaolin can be determined by a method of measuring the content of hydrous minerals in ash. The method for measuring the content of the hydrous mineral in the ash is not particularly limited, and can be measured by ccsem (computer Controlled scanning Electron microscopy) analysis, for example. Specifically, in the CCSEM analysis, the mass ratio of the water-containing mineral is quantified by the following procedure. First, a reflected electron image of the solid fuel is acquired, and the ash particles are identified by binarization processing. Next, for each particle identified, the coordinate position of the center of gravity point of the particle is identified from the aspect ratio, the shape such as roundness, the equivalent circle diameter calculated from the particle cross-sectional area, and the like. Elemental analysis was performed on the gravity center point of each particle based on these information, and the water-containing mineral was identified from the elemental composition ratio, and the mass ratio was quantified. In CCSEM analysis, these series of processes are automated by software, and a large amount of individual particle data can be acquired in a shorter time than in the analysis method in which a conventional average value is obtained, and thus highly accurate measurement can be performed efficiently. In this way, the content of hydrous minerals in the ash can be calculated.
In addition, in the content acquisition step (S1), it is preferable to measure the calorific value of each solid fuel in addition to the measurement of the ash. By measuring the calorific values of the respective solid fuels in this way, in the mixing and feeding step (S3) described later, the feeding amount of the solid fuel can be easily adjusted so that the amount of heat of the mixed solid fuel fed to the boiler becomes a required amount, and the boiler can be efficiently operated. Here, the calorific value of the solid fuel may be determined, for example, according to JIS-M-8814: the measurement method 2003 is to burn a solid fuel to perform measurement.
In order to obtain the content of ash, the content of kaolin in ash, the calorific value of solid fuel, and the like, it is necessary to generate ash by combusting each solid fuel in a boiler. This combustion does not necessarily need to be performed using a real boiler actually used, and may be performed using a combustion test furnace, for example.
The obtained ash content of each solid fuel, the obtained kaolin content in the ash, the obtained calorific value of the solid fuel, and the like may be recorded and stored in a storage device or the like, for example, in the form of data. By storing the data in this manner, the data can be used later. In the case of using the solid fuel in which the data has been stored, the content of ash, the content of kaolin in ash, the calorific value of the solid fuel, and the like in the content acquisition step (S1) are acquired using the data, and the measurement thereof can be omitted.
(mixing ratio determining step)
In the mixing ratio determining step (S2), the mixing ratio of the plurality of solid fuels is determined so that the content of the kaolin in the ash of the entire mixture of the plurality of solid fuels becomes equal to or less than a reference value, based on the content of the ash and the content of the kaolin of each of the plurality of solid fuels obtained in the obtaining step. This process is performed by the processor 5 of the boiler plant.
When the content of ash in each solid fuel is Ai, the content of kaolin in the ash is Ki, and the ratio to the entire fuel is Wi, the content R of kaolin in the ash of the entire mixture can be calculated by the following formula (1).
(number 1)
In the mixing ratio determining step (S2), the mixing ratio of the plurality of solid fuels is determined so that the kaolin content R is equal to or less than a reference value. In this method for operating a boiler, the kaolin content R is set to a reference value or less, thereby suppressing a decrease in the furnace heat storage rate.
Here, the reason why the decrease in the furnace heat storage rate can be suppressed by making the kaolin content R equal to or less than the reference value will be described. When the boiler is operated, ash of the solid fuel to be burned adheres to the furnace wall. The hydrous minerals contained in the ash that assists the furnace walls release crystal water in the minerals due to the heat of combustion of the furnace. The particles of the hydrous mineral that release crystal water are porous in structure. Ashes containing such water-containing minerals in a porous state have extremely low effective thermal conductivity. It is therefore assumed that: when the content of the hydrous mineral increases, the adhering ash becomes a heat insulating layer due to the porous structure, which hinders heat transfer and lowers the heat storage rate of the furnace. In contrast, it is considered that: when the content of the hydrous mineral is equal to or less than the reference value, the adiabatic property of the adhering ash is reduced, and therefore, the reduction of the heat storage rate of the furnace can be suppressed. Here, the kaolin accounts for a large mass ratio of hydrous minerals contained in the solid fuel used in the boiler. Therefore, the effect of suppressing the decrease in the heat storage rate of the furnace can be easily obtained by setting the kaolin content R to a reference value or less.
The present inventors conducted the following tests in order to confirm the optimum reference value of the kaolin content R based on the above theory. First, 3 kinds of coal were prepared as solid fuels. The ash content of these 3 kinds of coal and the kaolin content in the ash were obtained by burning coal using a pulverized coal fired boiler (power generation capacity 700 MW). The ash content of coal was determined by the following method in accordance with JIS-M-8812: 2006 by the measurement method of the following. The kaolin content in the ash was calculated by CCSEM analysis.
Next, 2 or 3 kinds of coals out of the 3 kinds of coals were used to determine the mixing ratio of the octant coals and calculate the kaolin content R. The coal mixture of the eights of coal mixed at the mixing ratio is applied to each real boiler for a fixed period of time, and the average value of the furnace heat storage rate in the period of time is obtained.
Thus, a graph of fig. 3 showing the relationship between the kaolin content and the heat storage rate in the furnace was obtained. The furnace heat storage rate is: the standard value is represented by assuming that the furnace heat storage rate under the condition of 1 in the octant mixed char is 1, and the larger the value is, the higher the furnace heat storage rate is. As is clear from the graph of fig. 3: the kaolin content has a correlation with the heat storage rate of the furnace, and the decrease in the heat storage rate of the furnace can be suppressed by setting the kaolin content to a constant value or less. Namely, it can be seen that: the mixing ratio of the solid fuel is determined so that the kaolin content is equal to or less than a reference value.
The reference value is preferably 40% by mass, more preferably 38% by mass, still more preferably 35% by mass, and particularly preferably 30% by mass. As can be seen from the graph of fig. 3: when the reference value is larger than the above value, the furnace heat storage rate is excessively decreased, and therefore there is a risk that the decrease in the furnace heat storage rate cannot be sufficiently suppressed.
(Mixed supply step)
In the mixing and supplying step (S3), the plurality of types of solid fuels are mixed in accordance with the mixing ratio determined in the mixing ratio determining step (S2), pulverized, and supplied to the furnace. Specifically, the amount of the solid fuel fed from the hopper 1 to the mixer 2 is adjusted by controlling the feed amount adjusting device 6 by the processor 5 of the boiler facility. The mixed solid fuel is pulverized by the pulverizer 3, and then blown into the boiler 4 together with air to be combusted.
(advantages)
In this method for operating a boiler, the mixing ratio of the plurality of types of solid fuels is determined so that the content of the hydrous minerals becomes equal to or less than the reference value, and therefore, the adhesion of porous ash due to the release of crystal water from the hydrous minerals can be suppressed. This reduces the heat insulating property of the adhering ash, and therefore, the boiler operation method can suppress a reduction in the furnace heat storage rate.
< steam turbine Generator plant >
The steam turbine generator facility mainly includes a steam turbine and a generator.
The steam turbine is an external combustion engine that converts the energy of the steam into rotational motion by means of a turbine (impeller) and a shaft, and is driven by the steam generated in the boiler plant.
The steam turbine is not particularly limited, and may include, for example, a high-temperature high-pressure turbine, a high-temperature reheat turbine, and a low-pressure turbine. At this time, the steam generated in the boiler plant first drives the high-temperature high-pressure turbine. The energy is lost by the driving of the high-temperature high-pressure turbine, and the steam with the reduced temperature and pressure is heated again by a reheater of the boiler plant. The high temperature reheat turbine is driven by the high temperature steam heated by the reheater. Further, the energy is lost by the driving of the high-temperature reheat turbine, and the steam having a reduced temperature and pressure is introduced into the condensed water supply facility after driving the low-pressure turbine.
The power of the high-temperature and high-pressure turbine, the high-temperature reheat turbine, and the low-pressure turbine driven by the steam drives a generator to obtain an electric output.
< condensed water supply facility >
The condensed water supply equipment mainly comprises a condenser, a pump, a heater and a degasser.
The condensed water supply apparatus cools the steam driving the steam turbine by using a condenser, and recovers the cooled steam as condensed water. The condensed water is pressurized by a pump, heated by a heater, and degassed by a degasser. The pressurized and heated condensed water is supplied to an economizer of the boiler facility as feed water for the boiler facility.
< advantages >
In a thermal power plant using the boiler plant, the heat storage rate in the furnace is not easily lowered by using the operation method of the boiler. Therefore, the thermal power plant facility using the boiler facility is easy to operate stably.
[ other embodiments ]
The method for operating a boiler and the boiler plant according to the present invention are not limited to the above-described embodiments.
In the above embodiment, the method of determining the mixing ratio of the plurality of types of solid fuels based on the content of kaolin was described as the method of operating the boiler and the boiler facility, but the mixing ratio of the solid fuels may be determined based on the content of gypsum in the ash and the content of other water-containing minerals.
Further, as the operation method of the boiler and the boiler plant, the mixing ratio can be determined according to the content of 2 or more kinds of hydrous minerals. When the mixing ratio is determined based on the content of 2 or more types of the hydrous minerals, the mixing ratio may be determined such that the sum of the content ratios of the hydrous minerals becomes equal to or less than a reference value, or the mixing ratio may be determined such that the content ratio of each hydrous mineral becomes equal to or less than a reference value. When the percentage of each mineral containing water is equal to or less than the reference value, the reference value may be different for each mineral containing water.
Examples
The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.
(solid Fuel)
First, 3 kinds of coal were prepared as solid fuels. The ash content of these 3 types of coal and the kaolin content in the ash were obtained by burning coal using a pulverized coal fired boiler (power generation capacity 700 MW). The ash content of coal was determined by the following method in accordance with JIS-M-8812: 2006 by the measurement method of the following. In addition, the content of kaolin in the ash was calculated based on the mass of kaolin obtained using CCSEM analysis. The results are shown in table 1.
[ TABLE 1 ]
(No.1～No.7)
Next, using 2 or 3 of these 3 kinds of coals, the mixing ratios of coals No.1 to No.7 shown in table 2 were selected, and the content of kaolin in the ash was calculated. Further, the coal mixture obtained by mixing coal at the mixing ratio shown in table 2 was used, and the coal mixture was operated in the real boiler for a fixed period of time, and the average value of the furnace heat storage rate in the period of time was obtained. The results are shown in table 2.
[ TABLE 2 ]
In table 2, the furnace heat accumulation rate is a value normalized by the furnace heat accumulation rate of No. 2.
As can be seen from Table 2: the kaolin content in the ash has a high correlation with the furnace heat storage rate regardless of the type of coal to be mixed, and the decrease in the furnace heat storage rate can be suppressed by setting the kaolin content to a reference value or less.
In nos. 1 to 6 in which the content of kaolin in ash is 40% or less, the heat storage rate in the furnace was more than 0.95, while in No.7 in which the content of kaolin was more than 40%, the heat storage rate in the furnace was less than 0.95. Thus, it can be seen that: the reference value of the kaolin content is set to 40%, whereby a high hearth heat storage rate of 0.95 or more is obtained.
Industrial applicability
As described above, the boiler operation method according to the present invention can suppress a decrease in the furnace heat storage rate.
Therefore, the boiler plant using the method for operating a boiler can be stably operated easily. The boiler using the method for operating the boiler is suitably used in a thermal power plant.
Description of the symbols
1 hopper
2 mixing machine
3 disintegrating machine
4 boiler
5 processor
6 supply amount adjusting device
7 burner
Claims (5)
1. A method for operating a boiler in which a plurality of solid fuels are mixed and combusted, the method comprising:
an obtaining step of obtaining the content of ash in the plurality of types of solid fuels and the content of at least 1 type of hydrous mineral in the ash; and
determining a mixing ratio of the plurality of types of solid fuels such that the content of the at least 1 type of hydrous mineral in the ash of the entire mixture of the plurality of types of solid fuels becomes equal to or less than a reference value, based on the content of the ash and the content of the at least 1 type of hydrous mineral of each of the plurality of types of solid fuels obtained in the obtaining step,
wherein the adhesion of porous ash resulting from the release of crystal water from the water-containing mineral is suppressed by setting the reference value to 40 mass%.
2. The method of operating a boiler according to claim 1, wherein the at least 1 hydrous mineral is kaolin or gypsum.
3. The method of operating a boiler according to claim 1 or 2, wherein the solid fuel is coal.
4. The method of operating a boiler according to claim 1 or 2, which is used for a thermal power plant.
5. The method according to claim 3, which is used for a thermal power plant.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015139986A JP6568420B2 (en) | 2015-07-13 | 2015-07-13 | Boiler operation method and boiler equipment |
| JP2015-139986 | 2015-07-13 |
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| CN102472484A (en) * | 2009-07-22 | 2012-05-23 | 株式会社神户制钢所 | Method for suppressing adhesion of ash and device for suppressing adhesion of ash in boiler |
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| US3907674A (en) * | 1974-04-24 | 1975-09-23 | Dorr Oliver Inc | Fluid bed incineration of wastes containing alkali metal chlorides |
| US4480593A (en) * | 1982-07-09 | 1984-11-06 | Robinson Insulation Co. | Method and composition to avoid ash build-up |
| JPS59193151A (en) * | 1983-04-18 | 1984-11-01 | バブコツク日立株式会社 | Prevention of clogging of coal supply pipe |
| JPS60185010A (en) * | 1984-03-01 | 1985-09-20 | Kobe Steel Ltd | Compounding method of coal |
| JPS62186955A (en) * | 1986-02-07 | 1987-08-15 | パトリシア ダンカン ステフアノフ | Jet type crushing system |
| US4917024A (en) * | 1989-05-24 | 1990-04-17 | Florida Institute Of Phosphate Research | Coal fired power plant with pollution control and useful byproducts |
| SU1766857A1 (en) * | 1990-11-30 | 1992-10-07 | Сибирский Филиал Всесоюзного Теплотехнического Научно-Исследовательского Института Им.Ф.Э.Дзержинского | Method for hydration of free calcium oxide in ashes with high calcium oxide in ashes with high calcium content |
| JPH09250708A (en) * | 1996-03-14 | 1997-09-22 | Babcock Hitachi Kk | Operation method for pulverized coal burn boiler |
| JP3464208B2 (en) * | 2001-10-30 | 2003-11-05 | ユニレックス株式会社 | Method and apparatus for producing composite solid fuel |
| JP4732740B2 (en) * | 2003-11-27 | 2011-07-27 | Ｊｆｅスチール株式会社 | Method of blowing used plastic into furnace, used plastic particles for blowing furnace, and method for producing the same |
| US8196533B2 (en) * | 2008-10-27 | 2012-06-12 | Kentucky-Tennessee Clay Co. | Methods for operating a fluidized-bed reactor |
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