JP6971784B2 - Operation method of solid fuel supply device and combustion equipment and solid fuel supply device - Google Patents

Description

The present invention relates to a solid fuel supply device and a combustion facility for supplying a carbon-containing solid fuel to a crusher, and a method for operating the solid fuel supply device.

Of the carbon-containing solid fuels supplied to combustion equipment such as boilers and integrated coal gasification combined cycle (IGCC), biomass fuel is carbon-neutral because it tackles carbon dioxide during the growth process of biomass. It is attracting attention as one of the measures to reduce carbon dioxide emissions from boilers that use fossil fuels. Biomass fuel such as wood is introduced into a crusher in the form of chips and pellets, crushed by the crusher, and then supplied to a burner installed in a boiler.
As a crusher for crushing biomass fuel, for example, there is an apparatus of Patent Document 1. In Patent Document 1, biomass fuel transported by truck is charged into a supply hopper via various devices and stored. The biomass fuel stored in the supply hopper is discharged to the measuring belt conveyor in predetermined amounts via the supply feeder, and after being quantified by the measuring belt conveyor, it is supplied to the vertical roller mill via the double flap gate. NS.

Japanese Unexamined Patent Publication No. 2008-208360

By the way, since the biomass fuel chips and pellets before crushing have a large particle size and are lightweight, a gap (a gap) formed between the biomass fuels when the biomass fuel is stored in a storage portion such as a supply hopper ( The gap formed between the biomass fuel and the adjacent biomass fuel) becomes large.
Normally, the pressure is high because the transport gas for transporting the pulverized fuel, which is the crushed solid fuel, is supplied to the inside of the crusher. Further, the storage unit communicates with the inside of the crusher in order to supply the solid fuel to the inside of the crusher.
As a result, when only the biomass fuel is stored in the storage section, the transport gas such as air blown up from the inside of the crusher and the fine powder fuel are prevented from passing through the gap formed between the biomass fuels. There is a possibility that the sealing property in the reservoir for this purpose will be reduced and the pressure inside the crusher will be reduced. When the transport gas blows through to the storage section, the biomass transportability in the storage section deteriorates and dust is generated, and when the pressure inside the crusher decreases, the amount of pulverized fuel transported decreases. Problems may occur.

In the apparatus of Patent Document 1, the air in the vertical roller mill is prevented from passing through the supply feeder through a double flap gate between the vertical roller mill and the supply feeder. However, since the double flap gate is installed between the vertical roller mill and the supply feeder, the installation cost increases, and maintenance is required for the double flap gate, which reduces the operability of the vertical roller mill. there is a possibility.

The present invention has been made in view of such circumstances, and by suppressing the flow rate of the backflow due to the blowing up of the transport gas and the fine powder fuel from the inside of the crusher passing through the storage portion, the inside of the crusher is suppressed. It is an object of the present invention to provide an operation method of a solid fuel supply device, a combustion facility, and a solid fuel supply device capable of suppressing an increase in installation cost and a decrease in operability by appropriately maintaining the pressure of the above. ..

In order to solve the above problems, the following means are adopted for the operation method of the solid fuel supply device and the combustion equipment and the solid fuel supply device of the present invention.
The solid fuel supply device according to one aspect of the present invention is a solid fuel supply device that supplies biomass fuel and coal as the solid fuel to a crusher that supplies pulverized fuel obtained by crushing the solid fuel to the boiler. A storage unit that stores the solid fuel supplied to the inside of the crusher, a biomass fuel transport unit that transports the biomass fuel to the storage unit, and a coal mixture that mixes coal with the biomass fuel that is transported to the storage unit. The coal mixing section is provided with a section, and the coal mixing section mixes the coal so that the mixing ratio of the coal in the solid fuel stored in the storage section is 4% by weight or more and 50% by weight or less.

In the above configuration, coal is mixed with the biomass fuel transported to the storage section. Therefore, the solid fuel stored in the storage unit is a mixture of biomass fuel and coal. Since coal has a smaller particle size than biomass fuel, it enters the gap formed between each biomass fuel stored in the reservoir. As a result, the coal closes the gap formed between the biomass fuels, making it difficult for the transport gas such as air and the pulverized fuel to pass through the storage section, and for transporting from the inside of the crusher that passes through the storage section. It is possible to suppress the flow rate at which gas and pulverized fuel are blown up and flow back. Therefore, the pressure inside the crusher can be suitably maintained.
Further, by mixing coal having a particle size smaller than that of the biomass fuel, the surface area of the entire solid fuel stored in the reservoir is increased. As the surface area of the entire solid fuel stored in the reservoir increases, the pressure loss between the transport gas and the pulverized fuel passing through the gaps of the stored solid fuel increases. As a result, it becomes difficult for the transport gas and the fine powder fuel to pass through the storage portion, so that it is possible to suppress the flow rate at which the transport gas and the fine powder fuel are blown up from the inside of the crusher passing through the storage portion and flow back. Therefore, the pressure inside the crusher can be suitably maintained.
In addition, a special device such as a rotary valve for suppressing the flow rate of transport gas and pulverized fuel blown up from the inside of the crusher passing through the storage section and backflow between the storage section and the crusher. Since it is not necessary to provide the above, it is possible to suppress an increase in installation cost and a decrease in operability.
Further, since the coal mixing section mixes coal so that the mixing ratio of coal in the solid fuel stored in the storage section is 4% by weight or more and 50% by weight or less, the solid fuel mainly composed of biomass fuel is used. Can be supplied to the boiler.

Further, in the solid fuel supply device according to one aspect of the present invention, in the coal mixing section, the mixing ratio of the coal in the solid fuel stored in the storage section is 5% by weight or more and 10% by weight or less. May be mixed with the coal.

If the mixing ratio of the coal to be mixed is small, the coal does not sufficiently enter the gap formed between the biomass fuels stored in the reservoir, and the transport gas and the pulverized fuel pass through the gap from the inside of the crusher. Therefore, it may not be possible to maintain the pressure inside the crusher appropriately.
On the other hand, if the mixing ratio of the coal to be mixed is large, for example, when the crusher has a configuration suitable for processing biomass fuel (for example, the housing shape, the rotation speed of the crushing table, the rotation speed of the rotary classifier, etc.). May not be able to properly process coal, which has different properties than biomass fuel. If the amount of pulverized coal fuel that cannot be properly processed in the crusher increases, the operating condition of the boiler may change, resulting in a decrease in combustibility.
Therefore, in the above configuration, the mixing ratio of the coal to be mixed is set to 5% by weight or more and 10% by weight or less. As a result, the pressure inside the crusher can be suitably maintained, and the operating state of the boiler can be prevented from deteriorating.

Further, the solid fuel supply device according to one aspect of the present invention is provided between the storage unit and the crusher, and has a supply unit that supplies the solid fuel stored in the storage unit to the crusher. The coal mixing unit may include a temperature measuring device for measuring the temperature in the supply unit, and the coal mixing unit may change the mixing ratio of the coal based on the temperature measured by the temperature measuring unit.

Since the high-temperature transport gas is supplied to the crusher, the temperature of the transport gas such as air in the crusher becomes high.
In the above configuration, since the supply unit is provided between the storage unit and the crusher, when the transport gas and the pulverized fuel in the crusher pass through the storage unit, the supply unit also circulates. .. Since the temperature of the transport gas in the crusher is high because the high temperature transport gas is distributed in the crusher, when the transport gas in the crusher and the fine powder fuel circulate in the supply section, the temperature in the supply section rises. To rise. In the above configuration, the temperature measuring device measures the temperature inside the supply unit. Therefore, it is possible to reliably detect whether or not the transport gas and the pulverized fuel in the crusher flow back and pass through the storage unit depending on the temperature in the supply unit. Further, since the mixing ratio of coal is changed based on the measured temperature, the mixing ratio of coal can be appropriately adjusted according to the flow rate of the transport gas and the pulverized fuel passing through the storage portion, which is more preferable. It is possible to suppress the flow rate of the transport gas and the pulverized fuel blown up from the inside of the crusher passing through the storage portion and flow back.
In addition, since the supply unit is provided between the storage unit and the crusher, the temperature measuring device measures the temperature relatively near the crusher when the transport gas blows up and a backflow occurs. Therefore, the transport gas is not significantly cooled by other structures or the like, and can be measured and sensed by the temperature measuring instrument at a relatively high temperature. Therefore, when the temperature measuring device measures the temperature, it is not easily affected by other environments. Therefore, it is possible to accurately determine whether or not the transport gas and the pulverized fuel have passed through the storage unit.

Further, the combustion equipment according to one aspect of the present invention is crushed by the solid fuel supply device according to any one of the above, a crusher for crushing the solid fuel supplied by the solid fuel supply device, and the crusher. It includes a combustion unit to which the solid fuel is supplied.

According to the above configuration, the pressure inside the crusher can be suitably maintained by suppressing the flow rate at which the transport gas and the pulverized fuel are blown up from the inside of the crusher passing through the storage portion and flow back. As a result, the supply of coal biomass fuel supplied to the crusher 2 can be stabilized, and the crusher can suitably process the solid fuel. Therefore, the properties of the pulverized fuel supplied to the combustion unit can be made appropriate, and the energy efficiency of the entire combustion equipment can be improved.

Further, the method of operating the solid fuel supply device according to one aspect of the present invention is to supply biomass fuel and coal as the solid fuel to a crusher that supplies pulverized fuel obtained by crushing the solid fuel to the boiler. A method of operating the apparatus, wherein the solid fuel supply device includes a storage unit for storing the solid fuel to be supplied inside the crusher, and a biomass fuel transfer step of transporting the biomass fuel to the storage unit, and the above-mentioned. A coal mixing step of mixing coal with the biomass fuel transported to the reservoir is provided, and in the coal mixing step, the mixing ratio of the coal in the solid fuel stored in the reservoir is 4% by weight or more. The coal is mixed so as to be 50% by weight or less.

According to the present invention, the pressure inside the crusher can be suitably maintained by suppressing the flow rate of the backflow due to the blowing up of the transport gas and the pulverized fuel from the inside of the crusher passing through the storage portion, and the installation cost can be reduced. It is possible to suppress the increase and the decrease in operability.

It is a schematic block diagram of the boiler equipment which concerns on 1st Embodiment of this invention. It is a graph which shows the relationship between the mixing ratio of coal and the sealing property, and the relationship between the mixing ratio of coal and combustibility. It is a figure which shows the model of the order arrangement state of a large particle size. It is a figure which shows the model of the dense arrangement state of a small particle size. It is a graph which shows the relationship between the small particle ratio and the sealing property. It is a schematic block diagram of the boiler equipment which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the mixing ratio change process of coal.

Hereinafter, an embodiment of the solid fuel supply device, the boiler equipment, and the operation method of the solid fuel supply device according to the present invention will be described with reference to the drawings.
[First Embodiment]
Hereinafter, the first embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a boiler facility 1 provided with a crusher 2, a solid fuel supply device 3, and a boiler main body (combustion unit) 4 according to the present embodiment. In the present embodiment, the upper direction indicates the vertical upper direction, and the lower direction indicates the vertical lower direction.

The boiler equipment (combustion equipment) 1 includes a crusher 2 that mainly crushes biomass fuel, which is a solid fuel supplied to the burner 9 provided in the boiler main body 4. Here, the biomass fuel is a renewable organic resource derived from living organisms, for example, woody biomass fuel such as thinned wood, waste wood, drifting wood, grass, waste, dehydrated sludge, non-woody material such as tires. Biomass fuel, etc. Further, the biomass fuel includes recycled fuel in the form of pellets or chips made from these as raw materials, and is not limited to those presented here.

A crushed material supply pipe 7 is connected to the crusher 2, and the pulverized fuel of the biomass fuel crushed by the crusher 2 is connected to the boiler main body 4 via the crushed material supply pipe 7 together with heated air as a transport gas. It is designed to be guided to the provided burner 9.

A flame is formed by the burner 9 in the furnace in the boiler main body 4, and steam is generated by a heat exchanger (not shown) in the boiler main body 4. The generated steam is guided to a steam turbine (not shown) to rotate and drive the steam turbine. When the steam turbine is rotationally driven, a generator (not shown) coupled to the rotating shaft of the steam turbine rotates to generate electricity.

Next, the crusher 2 will be described.
The housing 11 constituting the outer shell of the crusher 2 has a substantially cylindrical hollow shape, and a fuel supply pipe 13 is attached to the central portion of the ceiling portion 12. The fuel supply pipe 13 houses a biomass fuel (hereinafter, referred to as "coal mixed biomass fuel"; a method of mixing coal will be described later) mixed with a predetermined amount of coal derived from the solid fuel supply device 3. It is supplied to the inside of the housing 11, is arranged at the center position of the housing 11 along the vertical direction (vertical direction), and the lower end portion extends to the inside of the housing 11.

A gantry 14 is installed in the housing 11, and a crushing table 15 is rotatably arranged on the gantry 14. The lower end of the fuel supply pipe 13 is arranged so as to face the center of the crushing table 15. The fuel supply pipe 13 supplies the coal mixed biomass fuel from the upper side toward the lower crushing table 15. The crushing table 15 is rotatable around the central axis in the vertical direction (vertical direction) and is rotationally driven by the drive device 10.

A plurality of (for example, three) crushing rollers 16 are arranged above the crushing table 15 so as to face each other. The crushing rollers 16 are arranged above the outer peripheral portion of the crushing table 15 at equal intervals in the circumferential direction (note that only two crushing rollers 16 are shown in FIG. 1 due to the relationship shown in the figure). When the crushing table 15 rotates with the outer peripheral surface in contact with the upper surface of the crushing table 15, the crushing roller 16 receives rotational force from the crushing table 15 and rotates around. When the coal mixed biomass fuel is supplied from the fuel supply pipe 13, the coal mixed biomass fuel is pressed between the crushing roller 16 and the crushing table 15 and crushed to become fine powder fuel.

A transport gas supply pipe 20 is connected to the lower part of the housing 11. The transport gas supplied by the transport gas supply pipe 20 is guided into the housing 11 and supplied to the space located below the crushing table 15. The transport gas is set to a high temperature for preheating and drying of the solid fuel to be transported, and is set to, for example, about 120 ° C. to 150 ° C. (° C.). Therefore, the temperature of the space located below the crushing table 15 is about 120 to 150 degrees. As the transport gas in this embodiment, for example, air blown from a blower (not shown) is used. The temperature of the transport gas is adjusted by mixing heated air supplied via a heat exchanger (heater) such as an air preheater (not shown) that uses the combustion gas of the boiler body 4 as a heat source. You may.

A rotary classifier 21 is provided on the upper part of the housing 11. The rotary classifier 21 is arranged so as to surround the fuel supply pipe 13, and rotates around the fuel supply pipe 13 by a driving force from a driving device (not shown). As the rotary classifier 21 rotates, a plurality of fins 22 attached to the outer peripheral side thereof rotate in the circumferential direction. The crushed material crushed by the crushing table 15 and the crushing roller 16 is wound upward by the flow of the transport gas rising from the lower side of the crushing table 15 through the outer peripheral side of the crushing table 15. Of the crushed materials rolled up, the crushed material having a relatively large diameter is knocked down by the fins 22 and returned to the crushing table 15 to be crushed again. As a result, the crushed material is classified by the rotary classifier 21 into fine powder fuel. Since the transport gas is cooled by transporting the crushed material while drying it in the housing 11, the temperature of the upper space of the housing 11 is, for example, about 60 degrees.

A plurality of crushed material supply pipes 7 are connected to the ceiling portion 12. The crushed material supply pipe 7 discharges the fine powder fuel after being classified by the rotary classifier 21, and guides the transport gas mixed with the discharged fine powder fuel to the burner 9 of the boiler main body 4. The plurality of crushed material supply pipes 7 are connected to the plurality of openings provided corresponding to the ceiling portion 12, respectively. The number of crushed material supply pipes 7 varies depending on the size of the crusher 2 and the crushing capacity, but is generally in the range of 2 to 8 and is often 4 to 6. In addition, in FIG. 1, only one is shown because of the illustration.

The solid fuel supply device 3 is transported by a biomass fuel transfer device (biomass fuel transfer unit) 23 that transports the biomass fuel stored in the silo (not shown) to the bunker (storage unit) 25, and a biomass fuel transfer device 23. A coal supply device (coal mixing section) 24 that sprinkles coal substantially uniformly on the biomass fuel to mix the required amount of coal, and a bunker 25 that stores the coal mixed biomass fuel in which coal is mixed by the coal supply device 24. , A solid fuel supply machine (supply unit) 26 for supplying the coal mixed biomass fuel introduced from the bunker 25 to the crusher 2. Further, the solid fuel supply device 3 has a down spout (reservoir) 27 that directly connects the lower end of the bunker 25 and the solid fuel supply machine 26, and a seal gas such as air or an inert gas in the solid fuel supply machine 26. It is provided with a seal gas supply pipe 28 for supplying.

The biomass fuel transfer device 23 has a biomass fuel hopper 23a and a first belt conveyor 23b for temporarily storing the biomass fuel from the silo. The biomass fuel transfer device 23 transports the biomass fuel from the biomass fuel hopper 23a on the first belt conveyor 23b. In the state of being transported by the biomass fuel transport device 23, the biomass fuel is in the state of pellets because it has not been crushed. The size of the pellet is, for example, about 6 to 8 mm in diameter and about 40 mm or less in length. Further, the supply amount of the biomass fuel supplied to the bunker 25 is adjusted by the belt speed of the first belt conveyor 23b.

The coal supply device 24 has a coal hopper 24a and a second belt conveyor 24b for temporarily storing coal so that the downstream end of the second belt conveyor 24b is located above, for example, the first belt conveyor 23b. Have been placed. The coal supply device 24 adjusts the supply flow rate of coal fuel at the belt speed of the second belt conveyor 24b that carries the coal from the coal hopper 24a on the second belt conveyor 24b. Then, coal is dropped downward from the downstream end of the second belt conveyor 24b, and the coal is sprinkled substantially uniformly on the biomass fuel mounted on the first belt conveyor 23b. The coal supply device 24 prepares coal so that the mixing ratio of coal in the coal mixed biomass fuel stored in the bunker 25 is, for example, 4% by weight or more and 50% by weight or less, more preferably 5% by weight or more and 10% by weight or less. Mix.
The particle size of the coal (that is, the coal before crushing) supplied by the coal supply device 24 is, for example, about 7 to 8 mm in 80% passing particle size. The mixing ratio of coal in the coal-blended biomass fuel may be appropriately adjusted depending on the properties and particle size of the biomass fuel and coal. For example, the same effect can be obtained by setting it in an appropriate value range of 50% by weight or less. Can be done.
With biomass fuel, combustibility with the burner 9 of the boiler main body 4 can be ensured even if it is crushed into fine powder fuel that is coarser than coal. On the other hand, when the crusher 2 has a configuration suitable for processing biomass fuel (for example, the shape of the housing 11, the rotation speed of the crushing table 15, the rotation speed of the rotary classifier 21, etc.), the coal to be mixed is biomass. Coal having different properties from the fuel may not be properly processed and may be supplied to the burner 9 as fine powder fuel in a coarse state, which may deteriorate the combustion performance. Therefore, it is preferable to set an upper limit for increasing the mixing ratio of coal fuel with biomass fuel.

The bunker 25 is arranged substantially vertically below the downstream end of the first belt conveyor 23b. The bunker 25 is formed, for example, in a substantially cylindrical shape, and an inclined surface is formed so as to reduce the diameter from substantially the center in the vertical direction. The upper end of the down spout 27 is connected to the lower end of the bunker 25.

The solid fuel supply machine 26 has a housing 26a constituting the outer shell and a third belt conveyor 26b arranged inside the housing 26a. A down spout 27 is connected to the upper surface of the housing 26a, and a seal gas supply pipe 28 and a fuel supply pipe 13 are connected to the lower surface of the housing 26a. The upstream end of the third belt conveyor 26b is arranged below the connecting portion between the housing 26a and the down spout 27, and the downstream end of the third belt conveyor 26b is the connecting between the housing 26a and the fuel supply pipe 13. It is located above the part.

The down spout 27 is a metal pipe material extending linearly in the vertical direction (vertical direction), and a coal mixed biomass fuel is laminated inside. That is, the supply amount of the coal mixed biomass fuel supplied from the biomass fuel transfer device 23 to the bunker 25 and the supply amount of the coal mixed biomass fuel supplied from the solid fuel supply machine 26 into the crusher are balanced and down spouted. A coal mixed biomass fuel is loaded in 27. Further, the down spout 27 directly connects the lower end of the bunker 25 and the solid fuel supply machine 26, and the down spout 27 is, for example, backflowed by blowing up the transport gas and the fine fuel from the inside of the crusher 2. There is no special device such as a rotary valve for restraint. The size of the down spout 27 varies depending on the properties, particle size, supply amount, etc. of the solid fuel to be supplied. For example, when the diameter is about 600 mm, the length in the vertical direction is set to about 1 to 5 m, for example, the diameter. When is about 900 mm, the length in the vertical direction is set to about 2 to 5 m.

The seal gas supply pipe 28 supplies a seal gas such as air supplied from the seal gas supply device (not shown) to the inside of the housing 26a of the solid fuel supply machine 26. Due to the sealing gas, the inside of the housing 26a becomes higher pressure than the inside of the crusher 2. The seal gas is filled inside the housing 26a and circulates inside the crusher 2 via the fuel supply pipe 13. Since the temperature of the seal gas is about 30 degrees, the temperature inside the housing 26a is about 30 degrees during normal operation of the crusher 2. Therefore, as will be described later, it is easy to detect the backflow due to the blowing up of the transport gas and the fine powder fuel by the temperature measuring device 34.

The operation of the crusher 2 and the boiler equipment 1 according to the present embodiment for crushing the biomass fuel will be described below.

The biomass fuel stored in the silo is transported to the biomass fuel hopper 23a by a transport device (not shown), and is temporarily stored in the biomass fuel hopper 23a. The required amount of the biomass fuel temporarily stored in the biomass fuel hopper 23a is transported to the bunker 25 by the first belt conveyor 23b (biomass fuel transfer step).
On the other hand, the coal is transported to the coal hopper 24a by a transport device (not shown) and temporarily stored in the coal hopper 24a. The required amount of coal temporarily stored in the coal hopper 24a is carried by the second belt conveyor 24b. The coal carried by the second belt conveyor 24b falls onto the first belt conveyor 23b from the downstream end of the second belt conveyor 24b, for example. Since the biomass fuel is carried in the first belt conveyor 23b, the coal is sprinkled substantially uniformly on the biomass fuel to produce a coal mixed biomass fuel (coal mixing step). The coal-blended biomass fuel falls into the bunker 25 from the downstream end of the first belt conveyor 23b. The coal-blended biomass fuel that has fallen into the bunker 25 is loaded and stored inside the bunker 25 and the downspout 27.

The coal mixed biomass fuel stored inside the bunker 25 and the inside of the down spout 27 is carried by a third belt conveyor 26b built in the solid fuel feeder 26 and supplied to the fuel supply pipe 13. The coal mixed biomass fuel supplied to the fuel supply pipe 13 falls toward the inside of the crusher 2. At this time, the pressure inside the housing 26a of the solid fuel supply machine 26 is higher than the pressure inside the crusher 2 due to the seal gas supplied from the seal gas supply pipe 28 inside the solid fuel supply machine 26. It's getting higher. Therefore, the coal-blended biomass fuel is suitably dropped toward the inside of the crusher 2.

The coal mixed biomass fuel supplied into the crusher 2 falls on the crushing table 15, moves to the outer peripheral side by centrifugal force, is crushed between the plurality of crushing rollers 16 and the crushing table 15, and is pulverized fuel. It becomes. The crushed product of the crushed coal mixed biomass fuel rises in the crusher 2 by the transport gas blown into the crusher 2 through the transport gas supply pipe 20.

At the upper part of the crushing table 15, a rotary classifier 21 composed of a plurality of fins (blades) 22 is rotating, and the coarse and heavy crushed material is knocked down by the centrifugal force of the fins 22 so as to be repelled. 15 Returned to the top. The crushed product is repeatedly crushed on the crushing table 15 until the particle size becomes finer than the predetermined diameter. The pulverized material having a finer particle size passes through the rotary classifier 21 as fine pulverized fuel, is discharged from the pulverizer 2, and is conveyed to the outside through the pulverized material supply pipe 7. The transport gas mixed with the transported fine fuel is sent to the burner 9 of the boiler main body 4 and burned.

According to this embodiment, the following effects are exhibited.
In this embodiment, coal is mixed with the biomass fuel transported to the bunker 25. Therefore, the solid fuel stored in the bunker 25 and the downspout 27 becomes a coal mixed biomass fuel in which the biomass fuel and the coal are mixed. Since coal has a smaller particle size than the biomass fuel, in the coal mixed biomass fuel, the coal enters the gap formed between the biomass fuels. As a result, the coal closes the gap formed between the biomass fuels, so that it becomes difficult for the transport gas and the fine powder fuel from the inside of the crusher 2 to pass through the bunker 25 and the down spout 27. Therefore, it is possible to suppress the flow rate of the backflow due to the blowing up of the transport gas and the fine powder fuel from the inside of the crusher 2 passing through the bunker 25 and the down spout 27. That is, the coal-blended biomass fuel has improved sealing performance at the bunker 25 and the downspout 27 as compared with the coal-blended biomass fuel alone. Therefore, since the coal mixed biomass fuel stored in the bunker 25 and the down spout 27 serves as a sealing material, the pressure inside the crusher 2 can be suitably maintained. As a result, the transport gas mixed with the pulverized fuel is stably supplied to the burner 9 of the boiler main body 4 via the pulverized material supply pipe 7.

Further, by mixing coal having a particle size smaller than that of the biomass fuel, the surface area of the entire solid fuel stored in the bunker 25 and the downspout 27 is increased. Since the transport gas and the fine powder fuel from the inside of the crusher 2 that are about to pass through the bunker 25 and the down spout 27 circulate while in contact with the surface of the solid fuel, the solid fuel stored in the bunker 25 and the down spout 27 is stored. As the total surface area increases, the pressure loss when the transport gas and the pulverized fuel pass through the gap between the stored solid fuel increases. As a result, it becomes difficult for the transport gas and the fine powder fuel to pass through the bunker 25 and the down spout 27. The flow rate can be suppressed. Therefore, the pressure inside the crusher 2 can be suitably maintained. As a result, the transport gas mixed with the pulverized fuel is stably supplied to the burner 9 of the boiler main body 4 via the pulverized material supply pipe 7.

Further, the down spout 27 has a special device or the like (for example, a rotary valve or the like) for suppressing the flow rate of the backflow due to the blowing up of the transport gas and the pulverized fuel from the inside of the crusher 2 passing through the bunker 25 and the down spout 27. ) Is not required, so that it is possible to suppress an increase in installation cost and a decrease in operability as compared with the case where a device or the like is provided.

Further, according to the present embodiment, the pressure inside the crusher 2 is reduced by suppressing the flow rate of the backflow due to the blowing up of the transport gas and the pulverized fuel from the inside of the crusher 2 passing through the bunker 25 and the down spout 27. It can be suitably maintained. As a result, the supply of coal biomass fuel supplied to the crusher 2 can be stabilized, and the crusher 2 can suitably process the solid fuel. Therefore, the properties of the pulverized fuel supplied to the boiler main body 4 can be made appropriate, and the energy efficiency of the entire boiler equipment 1 can be improved.

Further, if the mixing ratio of the coal to be mixed is small, the coal does not sufficiently enter the gap formed between the biomass fuels stored in the bunker 25 and the down spout 27. As a result, the transport gas and the pulverized fuel from the inside of the crusher 2 pass through the gap, and there is a possibility that the pressure inside the crusher 2 cannot be appropriately maintained.
On the other hand, if the mixing ratio of the coal to be mixed is large, the coal may not be properly processed in the crusher 2. Specifically, since coal is not particularly flammable, it needs to be crushed more finely than the biomass fuel and supplied to the burner 9, but the crusher 2 has a configuration suitable for processing the biomass fuel (for example, housing shape, etc.). Since the rotation speed of the crushing table 15 and the rotation speed of the rotary classifier 21 are adjusted), the coal contained in the coal mixed biomass fuel is not crushed to the size required as the fine powder fuel of the coal. Includes. When coarse-grained coal is mixed with the crushed fine fuel and supplied to the burner 9, the combustibility of the burner 9 may decrease and the amount of unburned coal fine may increase. When the amount of unburned coal fine powder increases in the burner 9, ash accumulates on the bottom of the boiler main body 4, which may lead to a problem that the environmental friendliness is deteriorated due to an increase in CO generation amount and an increase in NOx. ..
In the present embodiment, the mixing ratio of the coal to be mixed is, for example, 4% by weight or more and 50% by weight or less, more preferably 5% by weight or more and 10% by weight or less. As a result, the pressure inside the crusher can be suitably maintained, and the decrease in combustibility in the boiler main body 4 can be prevented. The mixing ratio of coal in the coal-blended biomass fuel may be appropriately adjusted depending on the properties and particle size of the biomass fuel and coal. For example, the same effect can be obtained by setting it in an appropriate value range of 50% by weight or less. Can be done.

Here, the relationship between the effect of improving the sealing property of the coal-blended biomass fuel and the combustibility in the boiler main body 4 will be described with reference to FIG.

FIG. 2 shows the relationship between the mixing ratio of coal and the sealing property (indicated by the solid line in the figure) and the relationship between the mixing ratio of coal and the combustibility (indicated by the alternate long and short dash line in the figure). Regarding the relationship between the mixing ratio of coal and the sealing property, the case of 100% coal is shown as 1.0. Regarding the relationship between the mixing ratio of coal and combustibility, the case of 100% biomass fuel is shown as 1.0.

As is clear from FIG. 2, the sealing property with respect to the mixing ratio of coal improves as the mixing ratio of coal with the biomass fuel increases. Further, it can be seen that the sealing property is rapidly improved when the mixing ratio of coal is from 0% by weight to about 10% by weight, and saturated when the mixing ratio is about 50% by weight or more (see FIG. 5 described later). It can also be seen that the combustibility with respect to the mixing ratio of coal decreases as the mixing ratio of coal with the biomass fuel increases. As described above, the combustibility is adjusted to a configuration suitable for processing biomass fuel (for example, the shape of the housing, the rotation speed of the crushing table 15, the rotation speed of the rotary classifier 21, etc.), so that the mixing ratio of coal increases. This is because if the amount is excessive, coarse-grained coal is mixed with the fine powder fuel and supplied to the burner 9, so that the combustibility in the burner 9 is lowered.
From this, when the mixing ratio of coal is, for example, from 4% by weight to 50% by weight, the sealing property is at a high level without significantly reducing the combustibility, and more preferably between 5% by weight and 10% by weight. It can be seen that both the sealing property and the combustibility are at a high level.

The present invention has been made based on the finding that, as one of the features, the sealing property is greatly improved even if the mixing ratio of coal is low by weight%.
It can be seen from the following that the sealing property is greatly improved even if the mixing ratio of coal is low in weight%. Hereinafter, it will be described with reference to FIGS. 3 to 5.

In the present invention, the gap (porosity ε) formed between each biomass fuel is large only with the biomass fuel (large particle size particles), but the pores are formed by adding coal (small particle size particles). It has been found that the rate can be lowered and the sealing property can be rapidly improved.

Biomass fuel (large particle size particles) and coal (small particle size particles) are simulated and spherical, and biomass fuel (large particle size particles) has many pores, so it is orderly. It is in an aligned state. The porosity ε is the case where n particles having a particle size D are arranged in an orderly manner in the vertical and horizontal directions (see FIG. 3. In FIG. 3, three particles having a particle size D are arranged in an orderly manner, for example, in the vertical direction and in the horizontal direction. The case is shown.) Is represented by the following equation (1).
ε = 1-[[(π / 4) × D ² × n × n] / (D × n × D × n)] ... (1)
That is, the porosity ε is expressed by the following equation (2).
1- (π / 4) ... (2)
That is, when arranged in an orderly manner, the porosity ε is constant at about 21.5% regardless of the size of the particle size.

However, the particles having a small particle size (particle size d) (hereinafter referred to as "orderly arranged state") are opposed to the particles having a large particle size (particle size D) (biomass fuel in the present embodiment) in an orderly arrangement (hereinafter referred to as "ordered arrangement state"). In this embodiment, the densely arranged state (see FIG. 4; FIG. 4 shows, for example, a case where seven small particle size particles are arranged in the densely arranged state) is mixed. , The pore ratio ε becomes smaller. Here, by changing a single or a plurality of a part of the large particle size particles in the orderly arrangement state to the small particle size particles in the dense arrangement state, the small particle size with respect to the large particle size particles can be obtained. Simulate the mixing of particles. As an example, it is shown that, for example, one or a plurality of particles out of nine large particle size particles are changed to small particle size particles in a densely arranged state.

The pressure loss (Δp / L) per unit length of the fluid flowing through the solid particle packed bed is expressed by the following equation (3) from the Kozeny-Carman equation.
Δp / L = K × V × μ × Sv ² × (1-ε) ² / ε ³ ... (3)
However, K: Cozeny coefficient
V: Superficial velocity
μ: Fluid viscosity
ε: Porosity
Sv: Surface area per unit volume of particles

Since the leak flow rate is proportional to the superficial velocity obtained from the above Kozeny-Carman equation, the sealing property can be evaluated by the flow rate ratio at which leakage can be suppressed. Therefore, the sealing property can be expressed by the following formula (4).
[(Leakage flow rate in the reference state)-(Leakage flow rate in the state where the seal ratio is derived)] / (Leakage flow rate in the reference state) ... (4)

The graph of FIG. 5 shows the relationship between the small particle ratio and the sealing property.
In addition, in FIG. 5, the sealing property is represented by the following formula (5) following the above formula (4).
[Maximum leak flow rate (Ca = 0%)-Leakage flow rate (Ca = X%)] / Maximum leak flow rate (Ca = 0%) ... (5)
However, Ca: small particle ratio (ratio of small particles in a dense arrangement to the total number of large particles and small particles in a dense arrangement. For example, one of the large particles in FIG. 3 is a small particle in a dense arrangement. In the example of the case, the small particle ratio is 1/9, which is about 11%.)

The leak flow rate Q is represented by the following equation (6).
Q = K × V = K / (Δp / L) ・ ・ ・ (6)
However, K: Cozeny coefficient
V: Superficial velocity

As is clear from the graph of FIG. 5, it can be seen that the sealing property is rapidly improved at a low particle ratio. This is because the surface area Sv increases sharply and the pressure loss Δp / L increases by mixing the small particles.
Further, from the graph of FIG. 5, it is inferred that the sealing property is about 0.5 when the mixing ratio of coal is, for example, 4% by weight, the leakage flow rate is halved, and the leakage is greatly improved. It is presumed that when the mixing ratio is, for example, 50% by weight or more, the sealing property is saturated to about 1.0 and the leakage flow rate is almost eliminated. Further, considering the combustibility shown in FIG. 2 above, it is not preferable to greatly increase the mixing ratio of coal. Therefore, it is considered that the mixing ratio of coal is preferably from 4% by weight to 50% by weight from the viewpoint of sealing property. Be done.
Further, if the mixing ratio of coal is, for example, 5% by weight, the sealing property is about 0.6, the leakage flow rate is reduced to about 40%, and it is presumed that the problem due to leakage is almost eliminated, and the mixing ratio of coal is, for example, 10. When the weight is% by weight or more, the sealing property is about 0.8, and it is inferred that the sealing property is sufficient. Therefore, between 5% by weight and 10% by weight, the sealing property is sufficient, and both the sealing property and the combustibility including the combustibility shown in FIG. 2 described above are at a high level, which is considered to be more preferable. Be done.
Therefore, also from the above formula and graph, by mixing a small amount of small particle size particles (coal in this embodiment) with a large particle size particles (biomass fuel in this embodiment), the sealing property is rapidly improved. Can be seen to improve.

[Second Embodiment]
Subsequently, the second embodiment of the present invention will be described with reference to FIGS. 6 and 7. The solid fuel supply device 33 according to the present embodiment is different from the first embodiment in that it includes a temperature measuring device 34 and a control device 35. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 6, the temperature measuring device 34 is provided inside the solid fuel supply machine 26, for example, above the connecting portion between the solid fuel supply machine 26 and the fuel supply pipe 13. That is, the temperature measuring device 34 is provided in the vicinity of the upper end portion of the fuel supply pipe 13. The temperature measuring device 34 measures the temperature inside the housing 26a of the solid fuel supply machine 26, and transmits the measured temperature to the control device 35.

The control device 35 controls the coal supply device 24 based on the temperature measured by the temperature measuring device 34, and adjusts the mixing ratio of the coal to be mixed with the biomass fuel. Specifically, the belt speed of the second belt conveyor 24b of the coal supply device 24 is adjusted to adjust the amount of coal sprinkled on the biomass fuel.
The control device 35 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. As an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is installed in a ROM or other storage medium in advance, is provided in a state of being stored in a computer-readable storage medium, or is distributed via a wired or wireless communication means. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

Next, the mixing ratio changing process performed by the control device 35 of the present embodiment will be described with reference to the flowchart of FIG. 7.
First, the control device 35 acquires the temperature inside the solid fuel supply machine 26 measured by the temperature measuring machine 34 (S1). Next, it is determined whether or not the acquired temperature is equal to or higher than a predetermined temperature (S2). If the acquired temperature is equal to or higher than a predetermined temperature (for example, 50 degrees), the process proceeds to S3. If the acquired temperature is not higher than the predetermined temperature, the process returns to S1.

In S3, it is determined that a backflow is generated due to the blowing up of the transport gas and the pulverized fuel inside the crusher 2, and the belt speed of the second belt conveyor 24b of the coal supply device 24 is increased to increase the mixing ratio of coal. Increase from the specified weight%. Here, for example, it is increased by 1% by weight. When the mixing ratio of coal is increased by 1% by weight, the process proceeds to S4. In S4, the temperature inside the solid fuel supply machine 26 measured by the temperature measuring machine 34 is acquired, and it is determined whether or not the temperature rise has stopped. The determination of S4 may be carried out after a predetermined time has elapsed by increasing the mixing ratio of coal by 1% by weight in S3. If the temperature rise has stopped, the process proceeds to S5. If the temperature rise has not stopped, the process proceeds to S3, and the mixing ratio of coal is further increased by, for example, 1% by weight.

In S5, the coal is operated for a while without increasing the mixing amount of coal, and after a predetermined time elapses, the mixing ratio of coal is gradually reduced by, for example, 1% by weight to reach a predetermined value of weight%, which is a predetermined mixing ratio. return. When the mixing ratio of coal is returned to the predetermined mixing ratio, the process proceeds to S1.

The above control is an example, and numerical values and the like may be changed as appropriate. For example, the predetermined temperature for increasing the mixing ratio of coal is not limited to 50 degrees, and the temperature is based on the temperature of the transport gas that is blown up from the inside of the crusher 2 and flows back. Any temperature that can be sensed is sufficient. Further, the ratio of increasing the mixing ratio of coal is not limited to 1% by weight. It may be more than 1% by weight and less than 1% by weight.

According to this embodiment, the following effects are exhibited.
In the present embodiment, the solid fuel supply machine 26 in which the temperature measuring machine 34 measures the temperature is provided between the down spout 27 and the crusher 2. As a result, when the transport gas and the fine powder fuel in the crusher 2 pass through the down spout 27, they circulate in the solid fuel supply machine 26.
The temperature inside the solid fuel supply machine 26 is substantially the same as the temperature of the seal gas when operating normally, and is, for example, about 30 degrees. On the other hand, since the high temperature transport gas is supplied to the crusher 2, the temperature of the transport gas in the crusher 2 is high. The temperature inside the crusher 2 is, for example, about 60 degrees even in the upper space of the crusher 2 away from the connection portion of the transport gas supply pipe 20. Therefore, when the transport gas and the pulverized fuel in the crusher 2 flow through the solid fuel supply machine 26, the temperature in the solid fuel supply machine 26 rises.
In the present embodiment, the temperature measuring device 34 measures the temperature inside the solid fuel supply machine 26, and determines whether or not the temperature inside the solid fuel supply machine 26 is, for example, 50 degrees or more. As a result, when the temperature inside the solid fuel supply machine 26 rises to 50 degrees or higher, the transport gas and the fine fuel in the crusher 2 are blown up in the fuel supply pipe 13 and flow back to be solid. It can be determined that the fuel has flowed into the fuel supply machine 26 and has passed through the down spout 27 and the bunker 25. Therefore, it is possible to reliably detect whether or not the transport gas and the pulverized fuel in the crusher 2 have passed through the down spout 27 and the bunker 25 by a simple method.

Further, in the present embodiment, when it is determined that the transport gas and the pulverized fuel in the crusher 2 have passed through the down spout 27 and the bunker 25, the mixing ratio of coal is increased from the predetermined mixing ratio. It has been decreasing since then. As a result, the mixing ratio of the transport gas passing through the down spout 27 and the bunker 25 and the coal according to the flow rate of the backflow due to the blow-up of the pulverized fuel can be surely set, and the transport gas and the pulverized fuel in the crusher 2 can be surely set. Can be prevented from passing through the down spout 27 and the bunker 25, and the mixing ratio of coal can be excessively increased to prevent the combustion state of the boiler main body 4 from being lowered.

Further, since the solid fuel supply machine 26 is provided between the down spout 27 and the crusher 2, the temperature measuring machine 34 measures the temperature in a relatively close vicinity of the crusher 2. As a result, the transport gas is not significantly cooled by other structures or the like, so that it can be measured and sensed by the temperature measuring device 34 at a relatively high temperature. Therefore, when the temperature measuring device 34 measures the temperature, it is not easily affected by other environments such as the seal gas supplied into the solid fuel supply machine 26. Therefore, it is possible to accurately determine whether or not the backflow due to the blow-up of the transport gas and the fine powder fuel in the crusher 2 has passed through the down spout 27 and the bunker 25.

The present invention is not limited to the invention according to each of the above embodiments, and can be appropriately modified without departing from the gist thereof.
For example, in each of the above embodiments, coal is mixed with coal by sprinkling coal on the biomass fuel conveyed on the first belt conveyor 23b of the biomass fuel transfer device 23, but the coal supply device is used. Coal transported by the second belt conveyor 24b of 24 may be mixed by sprinkling biomass fuel. Alternatively, the biomass fuel and coal may be mixed by directly supplying the biomass fuel and coal from the biomass fuel transfer device 23 and the coal supply device 24 to the bunker 25.
Further, in each of the above embodiments, an example in which the solid fuel supply device is provided in the boiler facility 1 has been described, but the solid fuel supply device is used for a combustion device such as an integrated coal gasification combined cycle (IGCC). May be supplied with fuel.

1 Boiler equipment (combustion equipment)
2 Crusher 3 Solid fuel supply device 4 Boiler body (combustion part)
7 Crushed material supply pipe 9 Burner 11 Housing 13 Fuel supply pipe 15 Crushing table 16 Crushing roller 20 Transfer gas supply pipe 21 Rotary classifier 22 Fin 23 Biomass fuel transfer device (biomass fuel transfer unit)
24 Coal supply equipment (coal mixing section)
25 Banker (reservoir)
26 Solid fuel supply machine (supply section)
27 Down spout (reservoir)
28 Seal gas supply pipe 34 Temperature measuring machine 35 Control device

Claims (4)

A solid fuel supply device that supplies biomass fuel and coal as the solid fuel to a crusher that supplies pulverized solid fuel to the boiler.
A storage unit for storing the solid fuel supplied to the inside of the crusher,
A biomass fuel transport unit that transports the biomass fuel to the storage unit,
A coal mixing unit that mixes the coal with the biomass fuel transported to the storage unit,
A supply unit provided between the storage unit and the crusher and supplying the solid fuel stored in the storage unit to the crusher.
It is equipped with a temperature measuring device that measures the temperature inside the supply unit.
The coal mixing unit mixes the coal so that the mixing ratio of the coal in the solid fuel stored in the storage unit is 4% by weight or more and 50% by weight or less, and the temperature measured by the temperature measuring device. A solid fuel supply device that changes the mixing ratio of the coal based on the above. The solid fuel supply according to claim 1, wherein the coal mixing unit mixes the coal so that the mixing ratio of the coal in the solid fuel stored in the storage unit is 5% by weight or more and 10% by weight or less. Device. The solid fuel supply device according to claim 1 or 2,
A crusher that crushes the solid fuel supplied by the solid fuel supply device, and
A combustion facility including a combustion unit to which the solid fuel crushed by the crusher is supplied. It is a method of operating a solid fuel supply device that supplies biomass fuel and coal as the solid fuel to a crusher that supplies pulverized fuel obtained by crushing solid fuel to a boiler.
The solid fuel supply device includes a storage unit for storing the solid fuel supplied to the inside of the crusher.
A biomass fuel transporting process for transporting the biomass fuel to the storage unit,
A coal mixing step of mixing the coal with the biomass fuel transported to the storage unit,
A temperature measurement step provided between the storage unit and the crusher to measure the temperature in a supply unit that supplies the solid fuel stored in the storage unit to the crusher.
A changing step of changing the mixing ratio of the coal based on the temperature measured in the temperature measuring step is provided.
In the coal mixing step, a method for operating a solid fuel supply device that mixes the coal so that the mixing ratio of the coal in the solid fuel stored in the storage unit is 4% by weight or more and 50% by weight or less.

Images