JP4570591B2 - Method and system for reusing coarse particles recovered from fluidized bed boiler fuel production and supply equipment - Google Patents

Description

  The present invention relates to a method and system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility, and in particular, when the recovered coarse particles are used as part of the raw material for pulverized coal slurry, The present invention relates to a reuse method and a reuse system of coarse particles recovered from a fluidized bed boiler capable of keeping moisture and viscosity within a range of appropriate values.

  The pressurized fluidized bed boiler is a CWP (Coal Water Paste: coal, limestone and water) in a fluidized bed using limestone as a fluid medium (BM: bed material) while maintaining the pressurized state in the boiler with combustion air from the compressor. Is a boiler in which the CWP is combusted by charging the fuel.

  In such a pressurized fluidized bed boiler, fuel production and supply facilities are cleaned with water or air each time in order to prevent the CWP / slurry from clogging inside the stopped equipment and inside the pipe. Then, the coarse particles made of discharged CWP, pulverized coal slurry, etc. are stored in a coarse particle recovery tank (CWP recovery tank). In order to effectively use the coarse particles after recovery, the coarse particles stored in the coarse particle recovery tank are re-introduced into the pulverizer and recycled as part of the raw material for the pulverized coal slurry supplied to the fluidized bed boiler. It is common to use it.

  However, since the coarse particles to be reused contain various components, if they are re-added to the pulverizer as they are, there is a risk that combustion failure or the like will occur in the fluidized bed boiler. Therefore, various ideas have been conventionally made when reusing coarse particles.

  For example, in a “coal fired fluidized bed combustion apparatus” (Japanese Patent Publication No. Hei 3-505797: Patent Document 1), a fluid medium composed of sand and coal ash present in a fluidized bed is extracted from a boiler, sieved, and sieved. A technique is disclosed in which the coarse particles are pulverized by a pulverizer and fed again to a sieve, and the fine particles that have passed through the sieve are returned to the fluidized bed as a layer material.

  According to the “coal-fired fluidized bed combustion apparatus” described in Patent Document 1, the fluidized medium is adjusted to a predetermined particle size specific to the fluidized bed by a sieve and a pulverizer, thereby making the fluidized bed temperature uniform, It is said that the formation and deposition of massive slag from particles and ash can be avoided for a long time.

  In addition, in the fluidized bed boiler equipment provided with a fluidized bed combustion furnace using a desulfurization agent such as limestone as a fluidized medium in “fluidized bed boiler equipment” (Japanese Patent Laid-Open No. 2003-185104: Patent Document 2), laminar fluidity is provided. A technique is disclosed in which block products, incombustible minerals, and the like that are inhibited are extracted from a combustion furnace together with a fluid medium, and a desulfurizing agent is selected and reused.

  The “fluidized bed boiler facility” described in Patent Document 2 includes a combustion bed in which a fluidized bed formed of a fluidized medium is provided and coal is used as fuel, and a storage tank for storing a limestone desulfurization agent as the fluidized medium. A rotary feeder that supplies the fluidized medium in the storage tank to the fluidized bed, a fluid feeder from the combustion furnace, agglomerates generated by combustion, and a screw feeder that extracts incombustible minerals from coal by combustion, agglomerates from the extract, A coarse sieve for removing incombustible minerals and extracting a fluid medium, a fine sieve for removing fine particles from a fluid medium extracted by a coarse sieve and extracting a fine fluid medium of a predetermined size, and an extracted fine fluid medium By providing a connecting pipe that conveys air to the storage tank, the desulfurization agent that has been extracted from the fluidized bed and discarded can be reused.

JP-T-3-50579 JP 2003-185104 A

  By the way, coarse particles such as CWP and pulverized coal slurry recovered from a fluidized bed boiler fuel production and supply facility are reused when a certain amount is accumulated in the coarse particle recovery tank (CWP recovery tank). The properties vary depending on the cleaning conditions inside the equipment and inside the piping. Therefore, if the recovered coarse particles are supplied to the pulverizer as they are to produce a pulverized coal slurry, the moisture and viscosity of the pulverized coal slurry cannot be maintained within the proper range, resulting in poor combustion in the fluidized bed boiler. Etc. may occur.

  The technique described in Patent Document 1 described above is for optimizing the grain size of coarse particles, and the technique described in Patent Document 2 reuses a desulfurization agent (for example, limestone). There is no mention of keeping the moisture and viscosity of the pulverized coal slurry within the appropriate values.

  The present invention has been proposed in view of the above-described circumstances, and when the coarse particles recovered from the fluidized bed boiler fuel production and supply facility are reused as part of the raw material of the pulverized coal slurry, the moisture and viscosity of the pulverized coal slurry are reduced. An object of the present invention is to provide a method and a system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility that can be maintained within an appropriate range.

The method and system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility according to the present invention have the following features in order to achieve the above-described object.
That is, the method for reusing coarse particles recovered from the fluidized bed boiler fuel production and supply facility according to the present invention is to reuse the coarse particles recovered from the fluidized bed boiler fuel production and supply facility as part of the raw material of the pulverized coal slurry. A method of analyzing the properties of coarse particles recovered from a fluidized bed boiler fuel production and supply facility, a step of measuring the amount of coarse particles supplied as a raw material for pulverized coal slurry, and a supply as a raw material for pulverized coal slurry Detecting the moisture content of the coal to be measured, measuring the amount of coal supplied as the raw material of the pulverized coal slurry, the properties of the coarse particles, the supply amount of the coarse particles, the moisture content of the raw coal, and the raw coal amount Adjusting the amount of water injected to the fine pulverizer based on the above, supplying the coarse particles, the coal, and the raw water to the fine pulverizer, pulverizing and kneading, and supplying the fine powder to the fluidized bed boiler Charcoal It is characterized in that to produce the Li.

  Here, in the step of analyzing the properties of the coarse particles, it is preferable to detect the amount of coal contained and the amount of water contained in the coarse particles.

  In addition, the reuse system of the coarse particles recovered from the fluidized bed boiler fuel production and supply facility according to the present invention reuses the coarse particles recovered from the fluidized bed boiler fuel production and supply facility as a part of the raw material of the pulverized coal slurry. A pulverizer for producing pulverized coal slurry to be supplied as fuel to a fluidized bed boiler, a coal feeder for supplying raw coal to the pulverizer, and a raw material stored in the coal feeder A raw coal water meter that detects the moisture content of charcoal, a coal meter that measures the amount of coal supplied from a coal feeder to the pulverizer, and raw water that stores raw water for supply to the pulverizer A tank, a water injection amount adjusting means for adjusting the amount of raw water supplied from the raw water tank to the fine pulverizer, a coarse particle recovery tank for storing coarse particles recovered from a fluidized bed boiler fuel production and supply facility, and the coarse particle recovery Coarse grains stored in the tank A coarse particle property analyzing means for analyzing the shape, and a coarse particle amount meter for measuring the amount of coarse particles supplied from the coarse particle recovery tank to the fine pulverizer, wherein the water injection amount adjusting means comprises the raw coal water Based on the moisture content of the raw coal detected by the meter, the raw coal amount measured by the coal meter, the properties of the coarse particles analyzed by the coarse particle property analyzing means, and the coarse particle amount measured by the coarse particle meter The amount of raw water supplied to the fine pulverizer is adjusted.

  Here, it is preferable that the coarse grain property analyzing means detects the coal content and moisture content of the coarse grain.

  In the method and system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility according to the present invention, the properties of the coarse particles recovered from the fluidized bed boiler fuel production and supply facility are analyzed, and the moisture content of the raw coal The amount is detected, and the amount of water injected into the pulverizer is adjusted based on the properties of the coarse particles, the supply amount of the coarse particles, the moisture content of the raw coal, and the raw coal amount. Therefore, even if the recovered coarse particles have different properties, the moisture and viscosity of the pulverized coal slurry can be kept within the appropriate range, and the fluidized bed boiler can be operated stably.

  Moreover, it becomes possible to adjust the water content and viscosity of the pulverized coal slurry more appropriately and surely by adjusting the amount of water injected into the pulverizer based on the amount of coarse coal contained and the amount of water contained. .

<Outline of Coarse Grain Reuse Method and Coarse Grain Reuse System>
Hereinafter, with reference to drawings, an embodiment of a reuse method and a reuse system of coarse particles collected from fluid bed boiler fuel manufacture and supply equipment concerning the present invention is described.
A method and a system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility according to an embodiment of the present invention analyze the properties of the coarse particles recovered from a fluidized bed boiler fuel production and supply facility, and The amount of water injected into the pulverizer is adjusted based on the characteristics of the coarse particles, the amount of coarse particles supplied, the amount of moisture contained in the raw coal, and the amount of raw coal. .

  The method and system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility according to an embodiment of the present invention includes, for example, power generation employing a pressurized fluidized bed combined combustion (PFBC) system. Applied to the plant. This power plant drives a steam turbine with steam generated from a fluidized bed boiler housed in a pressure vessel, and further drives a gas turbine with exhaust gas from the boiler.

  In particular, this power plant has a CWP (Coal Water Paste: coal, limestone, and water) in a fluidized bed using limestone as a fluid medium (BM: bed material) while maintaining the pressure inside the boiler with combustion air from a compressor. CWP can be burned efficiently. Moreover, since it can desulfurize in a furnace by employ | adopting limestone as a fluid medium, generation | occurrence | production of sulfur oxide (SOx) can be suppressed low. Furthermore, in fluidized bed combustion, the combustion temperature can be kept low (about 860 ° C.), so that the generation of nitrogen oxides (NOx) can be kept low.

<Coarse grain reuse system>
FIG. 1 is a block diagram showing a schematic configuration of a system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility according to an embodiment of the present invention.
The coarse particle reuse system according to the embodiment of the present invention is a system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility as part of the raw material of the pulverized coal slurry, as shown in FIG. In addition, the fluidized bed boiler includes a coal feeder 1, a fine crusher (mill) 2, a raw water tank 3, a water injection pump 4, a slurry relay tank 5, and a CWP recovery tank (coarse grain recovery tank) 6 as main ancillary facilities. Etc. Further, the coal feeder 1 is provided with a raw coal moisture meter 7 for detecting the water content of the stored raw coal, and the raw coal supply path from the coal feeder 1 to the fine crusher 2 is the raw material. A coal meter 8 for measuring the amount of coal is provided.

  Although not shown in detail, the fuel supply system for supplying fuel to the fluidized bed boiler includes a coal hopper for supplying coal, a coarse pulverizer for coarsely pulverizing coal supplied from the coal hopper, and a coarse pulverizer. A classifier for classifying the pulverized coal powder, a relay hopper for relaying the coal powder classified by the classifier, and a fine pulverizer 2 for further pulverizing the coal powder pulverized by the coarse pulverizer while mixing water , Limestone hopper for supplying limestone, water, coal powder pulverized by coarse pulverizer, coal paste pulverized while mixing water with fine pulverizer 2, and kneader for kneading limestone, and kneading by kneader A fuel tank for temporarily storing the CWP, and a fuel pump for sending the CWP from the fuel tank into the furnace.

  The coarse particle supply path for supplying coarse particles from the CWP recovery tank 6 to the fine pulverizer 2 is provided with a coarse particle supply pump 9 and a coarse particle flow meter 10. Further, the CWP recovery tank 6 and the coarse grain supply pump 9 are connected via a coarse grain circulation path, and this coarse grain circulation path is used for analyzing the properties of the coarse grains stored in the CWP recovery tank 6. A coarse grain property analyzer 11 is provided.

  This coarse grain property analyzer 11 is an apparatus for detecting the amount of coal contained and the amount of moisture contained in the recovered coarse particles. For example, the amount of coal contained is detected by a turbidimeter, and the amount of moisture contained by a moisture meter is detected. It comes to detect. The coarse-grained property analyzer 11 may be any device as long as it can detect at least one of the recovered coarse-grained coal content or moisture content, and uses a known component sensor. it can.

  Further, a flow rate adjusting valve 12 is provided on the rear stage side of the water injection pump 4 for sending the raw water from the raw water tank 3, and an opening degree adjusting means 13 is connected to the flow rate adjusting valve 12. The opening degree adjusting means 13 is a means for adjusting the amount of raw water supplied from the raw water tank 3 to the fine pulverizer 2 by adjusting the opening degree of the flow rate adjusting valve 12, and is controlled by a computer system and its accessory equipment. Composed. That is, the function as the opening degree adjusting means 13 is exhibited when the CPU or the like constituting the computer system operates according to the application program.

The opening degree adjusting means 13 is connected with a raw coal moisture meter 7, a raw coal amount meter 8, a coarse particle flow meter 10, a coarse particle property analyzer 11, and a flow rate control valve 12, and the coarse particle properties (containing) Based on the amount of coal, the amount of water contained), the amount of coarse particles, the amount of water contained in the raw coal, and the amount of raw coal, the amount of water injected into the fine pulverizer 2 is adjusted. At this time, the amount of water injected into the pulverizer 2 is determined based on the viscosity and water content of the pulverized coal slurry to be produced. Specifically, for example, the amount of water injected into the pulverizer 2 is adjusted so that the viscosity of the produced pulverized coal slurry is 100 to 400 mPa · s and the water content is 49 to 51 w%.
In the coarse particle reuse system according to the present embodiment, the flow rate adjusting valve 12 and the opening degree adjusting means 13 function as a water injection amount adjusting means for adjusting the amount of raw material water supplied from the raw water tank to the fine pulverizer 2.

<Coarse grain reuse method>
Next, a procedure of a method for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility according to an embodiment of the present invention will be described. FIG. 2 is a flowchart showing a procedure of a method for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility according to an embodiment of the present invention.

  In the coarse particle reuse method of the present embodiment, as shown in FIG. 2, the properties of the coarse particles recovered from the fluidized bed boiler fuel production and supply facility are analyzed (S1), and the amount of coarse particles supplied as a raw material for the pulverized coal slurry (S2), detecting the moisture content of the coal supplied as the raw material for the pulverized coal slurry (S3), measuring the amount of coal supplied as the raw material for the pulverized coal slurry (S4), Based on the amount of grains, the moisture content of coal, and the amount of raw coal, the amount of water injected into the pulverizer is adjusted (S5).

  The order of the coarse particle property analysis step (S1), the coarse flow rate measurement step (S2), the raw water content detection step (S3), and the raw coal measurement step (S4) is in any order. It can be done or all steps can be done in parallel.

  After performing such weighing and analysis steps (S1 to S5), coarse particles, coal, and raw water are supplied to a fine pulverizer, pulverized and kneaded, and a pulverized coal slurry supplied to a fluidized bed boiler is manufactured. (S6).

  In the coarse grain property analysis step (S1), it is preferable to detect the amount of coal and the amount of moisture contained in the coarse particles.

  Thus, according to the reuse method and reuse system of the coarse particles recovered from the fluidized bed boiler fuel production and supply facility according to the present invention, the amount of water supplied to the pulverizer is adjusted based on the properties of the coarse particles. Therefore, it becomes possible to keep the moisture and viscosity of the pulverized coal slurry within the appropriate range.

  The method and system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility according to the present invention mainly includes CWP and pulverized coal slurry recovered from a fluidized bed boiler fuel production and supply facility such as a pressurized fluidized bed boiler. When the coarse particles composed of, for example, are used as a part of the raw material of the pulverized coal slurry, it can be used to keep the moisture and viscosity of the pulverized coal slurry within the appropriate values.

It is a block diagram which shows schematic structure of the reuse system of the coarse grain collect | recovered from the fluid bed boiler fuel manufacture and supply equipment which concerns on embodiment of this invention. It is a flowchart which shows the procedure of the reuse method of the coarse grain collect | recovered from the fluid bed boiler fuel manufacture and supply equipment which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coal feeder 2 Fine grinder 3 Raw water tank 4 Water injection pump 5 Slurry relay tank 6 CWP recovery tank 7 Coal water meter 8 Coal meter 9 Coarse feed pump 10 Coarse flow meter 11 Coarse grain property analyzer 12 Coarse flow control Valve 13 opening adjustment means

Claims (4)

A method for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility as part of a raw material of a pulverized coal slurry,
Analyzing the properties of the coarse particles recovered from the fluidized bed boiler fuel production and supply facility;
Measuring the amount of coarse particles supplied as a raw material for the pulverized coal slurry;
Detecting the moisture content of coal supplied as a raw material for the pulverized coal slurry;
Measuring the amount of coal supplied as a raw material for the pulverized coal slurry;
Adjusting the amount of water injected into the fine pulverizer based on the properties of the coarse particles, the supply amount of the coarse particles, the moisture content of the raw coal, and the raw coal amount,
The coarse particles, the coal, and the raw water are supplied to a fine pulverizer, pulverized and kneaded, and recovered from a fluidized bed boiler fuel production and supply facility for producing a pulverized coal slurry supplied to a fluidized bed boiler. Coarse grain reuse method.   2. The step of analyzing the properties of the coarse particles detects the amount of coal contained in the coarse particles and the amount of water contained therein. How to Use. A system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility as part of a raw material for pulverized coal slurry,
A pulverizer for producing a pulverized coal slurry to be supplied as fuel to a fluidized bed boiler;
A coal feeder for supplying raw coal to the pulverizer;
A coking coal moisture meter for detecting the moisture content of coking coal stored in the coal feeder;
A coal meter for measuring the amount of coal supplied from the coal feeder to the pulverizer;
A raw water tank for storing raw water to be supplied to the fine pulverizer;
Water injection amount adjusting means for adjusting the amount of raw material water supplied from the raw water tank to the fine pulverizer;
A coarse particle recovery tank for storing coarse particles recovered from a fluidized bed boiler fuel production and supply facility;
Coarse grain property analyzing means for analyzing the properties of the coarse particles stored in the coarse grain recovery tank;
A coarse particle meter for measuring the amount of coarse particles supplied from the coarse particle recovery tank to the fine pulverizer;
With
The water injection amount adjusting means includes the moisture content of the raw coal detected by the raw coal moisture meter, the raw coal amount measured by the coal meter, the characteristics of the coarse particles analyzed by the coarse grain property analyzing means, and the coarse coal A system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility, wherein the amount of raw water supplied to the fine pulverizer is adjusted based on the amount of coarse particles measured by a particle meter. 4. The system for reusing coarse particles recovered from a fluidized bed boiler fuel production and supply facility according to claim 3, wherein the coarse particle property analyzing means detects the amount of coal contained and the amount of water contained in the coarse particles.

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