Fuel supply system, boiler equipment, fuel supply system operation method, and fuel supply system modification method

Abstract

To provide a fuel supply system capable of modifying an existing coal fuel boiler facility to a biomass boiler facility without lifting a floor level.SOLUTION: A fuel supply system 100 for supplying fuel to a boiler facility includes: a bunker 13 storing solid fuel; a fuel supply device 50 supplying solid fuel to a crusher 5 crushing the solid fuel; a down spout 52 comprising piping connecting the bunker 13 and the fuel supply device 50; and a rotary valve 47. The rotary valve 47 is disposed on the down spout 52.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a fuel supply system, a boiler facility, a method for operating a fuel supply system, and a method for modifying a fuel supply system. [Background technology]

[0002] Patent Document 1 discloses a fuel supply system that "includes upper piping 49 connected to a fuel supplier 50 that supplies a predetermined amount of fuel before pulverization, lower piping 45 that is connected to the pulverizer 5 and introduces the fuel to the pulverizer 5, and an exchange section that is provided between the upper piping 49 and the lower piping 45 and that allows the rotary valve 47 and the short pipe to be exchanged (abstract excerpt)." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-39617 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, as shown in FIG. 8, in order to convert an existing fuel supply system 100a for coal fuel into a fuel supply system 100b for biomass fuel, the upper floor F2 on which the fuel supply device 50 is installed is raised by a height ΔH (the floor level is raised), and a rotary valve 47 is installed between the lower piping 45 and the upper piping 49.

[0005] However, in order to raise the floor level of the upper floor F2, it is necessary to erect scaffolding for the construction work, which poses the problem of high costs for the modification work.

[0006] Furthermore, although the rotary valve 47 requires periodic maintenance, there is no floor at the installation location of the rotary valve 47 in Patent Document 1, so a floor for maintenance needs to be constructed, which also poses a cost issue.

[0007] Furthermore, depending on the coal boiler equipment, there may not be enough space to install the rotary valve 47 between the fuel supply device 50 and the pulverized coal machine pipe (not shown), which poses the problem of not being able to switch from coal fuel to biomass fuel.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to provide a fuel supply system that can convert existing coal-fired boiler equipment into biomass-fired boiler equipment without raising the floor level. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention has the configurations described in the claims. As an example, the present invention is a fuel supply system for supplying fuel to boiler equipment, comprising: a bunker for storing solid fuel; a fuel supplier for supplying the solid fuel to a crusher for crushing the solid fuel; a downspout consisting of piping connecting the bunker and the fuel supplier; and a rotary valve, wherein the rotary valve is disposed on the downspout.

[0010] According to the above invention, the rotary valve required when using biomass fuel is installed on top of the fuel supply machine, so the rotary valve can be added without raising the floor level of the fuel supply machine. Furthermore, even in existing fuel supply systems for coal fuels where there is no space between the grinder and the fuel supply machine to add a rotary valve, installing a rotary valve on the downspout makes it possible to convert the system to use biomass fuel.

[0011] The present invention also provides a boiler facility comprising the fuel supply system described above and a boiler body to which fuel is supplied from the pulverizer.

[0012] According to the above invention, a coal-fired boiler facility can be converted into a biomass-fired boiler facility.

[0013] The present invention also provides an operating method for a fuel supply system that supplies fuel to a boiler, wherein the boiler comprises a bunker for storing solid fuel, a fuel supplier that supplies the solid fuel to a pulverizer that pulverizes the solid fuel, a downspout consisting of piping connecting the bunker and the fuel supplier, a rotary valve arranged on the downspout, a valve motor that rotates the rotary valve, and a valve control device that controls the rotational speed of the valve motor, wherein the valve control device includes the steps of: calculating an actual supply amount of fuel being supplied from the fuel supplier to the pulverizer; and acquiring a set value according to the operating load of the boiler, comparing the set value with the actual supply amount, and controlling the rotational speed of the valve motor so that the difference approaches zero.

[0014] According to the above invention, the amount of fuel supplied from the rotary valve to the pulverizer via the fuel supply machine can be adjusted by measuring the actual amount of fuel supplied while transporting the fuel from the downspout to the pulverizer and controlling the rotation speed of the valve motor so that the measured value approaches a set value according to the operating load.

[0015] Also, there is provided a method for retrofitting a fuel supply system for coal fuel into a fuel supply system for biomass fuel, the fuel supply system for coal fuel comprising: a pulverizer for pulverizing coal fuel; a fuel supply machine for supplying the coal fuel to the pulverizer; a bunker for storing the coal fuel; and a downspout consisting of piping connecting the bunker and the fuel supply machine, the method comprising the step of installing a new rotary valve on the downspout without changing the floor level of the fuel supply machine.

[0016] According to the above invention, the rotary valve required when using biomass fuel is installed on top of the fuel supply machine, so the rotary valve can be added without raising the floor level of the fuel supply machine. Furthermore, even in existing fuel supply systems for coal fuels where there is no space between the grinder and the fuel supply machine to add a rotary valve, installing a rotary valve on the downspout makes it possible to convert the system to use biomass fuel. [Effects of the Invention]

[0017] According to the present invention, an existing coal-fired boiler facility can be converted into a biomass-fired boiler facility without raising the floor level. Note that other issues, configurations, and effects will become clear from the following description of the embodiment. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic configuration diagram of a boiler facility equipped with a fuel supply system according to an embodiment of the present invention; [Figure 2] 1 is a diagram showing a schematic configuration of a fuel supply system according to an embodiment of the present invention; [Figure 3] FIG. 2 is a diagram showing a schematic configuration of a fuel supply machine. [Figure 4] FIG. 2 is a hardware configuration diagram of a valve control device of a fuel supply system. [Figure 5] FIG. 2 is a functional block diagram of a valve control device of a fuel supply system. [Figure 6] 3 is a flowchart showing a method for operating the fuel supply system according to the present embodiment. [Figure 7] FIG. 7 is an explanatory diagram of the process of step S02 shown in FIG. 6. [Figure 8] FIG. 1 is an explanatory diagram of a conventional fuel supply system. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, a fuel supply system and a boiler facility 1 according to an embodiment of the present invention will be described with reference to the drawings. The same components are designated by the same reference numerals throughout the drawings, and duplicated explanations will be omitted.

[0020] 1 is a schematic configuration diagram of a boiler facility 1 equipped with a fuel supply system according to this embodiment. In the following description, in this embodiment, "upper" refers to the vertically upper direction, and "lower" refers to the vertically lower direction.

[0021] The boiler facility 1 is equipped with a pulverizer 5 that pulverizes the biomass fuel and coal fuel to be supplied to the boiler body 3. Here, biomass fuel refers to a renewable organic resource derived from living organisms, such as thinned wood, scrap wood, driftwood, grass, waste, sludge, tires, and recycled fuels (pellets and chips) made from these materials, but is not limited to the examples presented here. Biomass fuel is carbon-neutral, meaning it does not emit carbon dioxide, a greenhouse gas, because it absorbs carbon dioxide during the biomass growth process, and various uses for it are being considered.

[0022] A pulverized fuel supply pipe 7 is connected to the pulverizer 5, and the pulverized fuel pulverized by the pulverizer 5 is led to a burner 9 via the pulverized fuel supply pipe 7 together with hot air serving as a carrier gas.

[0023] Biomass fuel stored in a biomass silo 11 is introduced to the crusher 5 via a bunker 13 .

[0024] A hot air supply pipe 15 is connected to the pulverizer 5. The hot air supply pipe 15 is connected to a primary ventilator 17, and is configured to introduce temperature-adjusted air obtained by mixing air preheated by an air preheater 19 with air that bypasses the air preheater 19. In addition, a portion of the exhaust gas that has passed through an electrostatic precipitator 23 via a gas recirculation ventilator 21 is introduced to the hot air supply pipe 15. Therefore, a mixture whose temperature has been adjusted by the air preheater 19 and whose oxygen concentration has been adjusted by the exhaust gas is introduced to the pulverizer 5 via the hot air supply pipe 15.

[0025] A flame is formed by a burner 9 in a furnace inside the boiler body 3, and steam is generated by a heat exchanger (not shown) inside the boiler body 3. The generated steam is guided to a steam turbine (not shown) to generate electricity.

[0026] The exhaust gas discharged from the boiler main body 3 is denitrated by the denitration device 25, and then the air guided from the primary fan 17 is heated in the air preheater 19, after which it is guided to the electrostatic precipitator 23. The exhaust gas is dedusted by the electrostatic precipitator 23, and then guided to the desulfurization device 29 via the induced draft fan 27. A portion of the exhaust gas is extracted upstream of the induced draft fan 27 and guided to the hot air supply pipe 15 via the gas recirculation fan 21.

[0027] The exhaust gas guided from the induced draft fan 27 is desulfurized in a desulfurization device 29, and then guided to a chimney 31 and released into the atmosphere.

[0028] Fig. 2 is a diagram showing a schematic configuration of the fuel supply system 100 according to this embodiment. Fig. 3 is a diagram showing a schematic configuration of the fuel supply machine 50.

[0029] As shown in Fig. 2, the fuel supply system 100 is composed of a bunker 13 to a crusher 5. Note that Fig. 2 illustrates a conventional fuel supply system 100a for coal fuel for comparison with the fuel supply system 100 according to this embodiment at floor level.

[0030] The fuel supply system 100 supplies the solid fuel stored in the bunker 13 to the pulverizer 5 via the fuel supplier 50.

[0031] The pulverizer 5 is a pressurized vertical mill that pulverizes solid materials such as coal fuel and biomass fuel. The pulverizer 5 includes a pulverizer table 42 that rotates about a central axis extending vertically, and a pulverizer roller 43 that is provided facing the upper surface of the pulverizer table 42. The coal fuel or biomass fuel (pellets) is pulverized between the pulverizer table 42 and the pulverizer roller 43. The pulverized fuel is stirred up by hot air supplied from the hot air supply pipe 15 (see FIG. 1), passes through a rotary separator 44 where it is classified by fine powder size, and is then guided through the pulverized fuel supply pipe 7 (see FIG. 1) to the burner 9 of the boiler main body 3.

[0032] A lower pipe 45 is fixed to the center of the upper part of the crusher 5. A fuel supplier 50 is connected above the lower pipe 45.

[0033] The fuel supplier 50 supplies solid fuel to the crusher 5. As shown in FIG. 3, the interior of the fuel supplier 50 includes a belt 501, a drive rotor 502 that transports the belt 501, a driven roller 503, and a load cell 504. The rotation speed of the drive rotor 502 is adjusted by a belt motor 505. The belt 501 is wound around the outer periphery of the drive rotor 502 and the driven roller 503. The belt 501 and the driven roller 503 rotate in accordance with the rotation of the drive rotor 502. The physical quantities shown in FIG. 3 will be described later.

[0034] Above the fuel supply machine 50, a downspout 52, a rotary valve 47, and a bunker 13 are connected.

[0035] 2, downspout 52 is a pipe that extends vertically and connects the upper part of fuel supply device 50 to the lower part of rotary valve 47, and the upper part of rotary valve 47 to the lower part of bunker 13. Downspout 52 is divided into lower downspout 52u below rotary valve 47 and upper downspout 52t above rotary valve 47.

[0036] The rotary valve 47 has a rotating section with multiple small storage chambers partitioned in the direction of rotation within the valve housing. Because the small storage chambers formed in the rotating section are independent, the flow of pressurized gas upward from the lower downspout 52u can be sealed even when biomass fuel is being supplied.

[0037] A seal air pipe 47a is connected to the rotary valve 47 via a seal air valve 47a1. The seal air supplied from the seal air pipe 47a seals the sliding portion between the valve housing and the rotating part.

[0038] A valve motor 47b (see FIG. 3) is connected to the rotary valve 47. The rotation speed of the valve motor 47b is controlled by a valve control device 200 (see FIG. 3) described later.

[0039] The upper downspout 52t holds fuel in a layered state inside. When biomass fuel is used, gaps exist between the pellet-shaped biomass fuel, and the sealing provided by the fuel layer in the upper downspout 52t is insufficient compared to coal fuel. For this reason, when using biomass fuel, a rotary valve 47 is provided below the upper downspout 52t to ensure sealing that prevents the pressurized gas on the fuel supply device 50 side from flowing back into the bunker 13 side. The biomass fuel does not accumulate in the lower downspout 52u, but falls to the fuel supply device 50.

[0040] The bunker 13 stores pellet-shaped biomass fuel.

[0041] 2, when the fuel supply system 100 and the conventional coal fuel fuel supply system 100a are installed on the same lower floor F1, the fuel supplier 50 is also installed on the upper floor F2 at the same floor level. Therefore, when converting the coal fuel fuel supply system 100a into the biomass fuel supply system 100 according to this embodiment, there is no need to lift the fuel supplier 50 (raise the floor level).

[0042] FIG. 4 is a hardware configuration diagram of the valve control device 200 of the fuel supply system 100. As shown in FIG.

[0043] The valve control device 200 is configured using a computer that includes a processor 201, a RAM (Random Access Memory) 202, a ROM (Read Only Memory) 203, a HDD (Hard Disk Drive) 204, an input I / F 205, an output I / F 206, and a communication I / F 207, all of which are connected to one another via a bus 208. The processor 201 is, for example, a CPU (Central Processing Unit), and any type of device can be used as long as it executes a calculation function. Furthermore, the hardware configuration of the valve control device 200 is not limited to the above, and may be configured by combining a control circuit and a storage device.

[0044] An input device 211 such as a mouse, keyboard, or touch panel is connected to the input I / F 205 .

[0045] The output I / F 206 is connected to a display 212 such as an LCD.

[0046] The communication I / F 207 is connected to the central operation room 2 and the valve motor 47b.

[0047] FIG. 5 is a functional block diagram of the valve control device 200 of the fuel supply system 100.

[0048] The valve control device 200 includes a supply amount calculation unit 201a and a rotary valve control unit 201b. These units are configured by hardware and software working together as a result of the processor 201 loading programs stored in the ROM 203 or HDD 204 into the RAM 202 and executing them. The functions of each unit will be described later.

[0049] 6 is a flowchart showing the method of operating the fuel supply system 100 according to this embodiment. FIG. 7 is an explanatory diagram of the process of step S02 shown in FIG.

[0050] The supply amount calculation unit 201a calculates the actual fuel supply amount C that is loaded on the belt 501 in the fuel supply machine 50 and supplied to the crusher 5. real The mass measured by the load cell 504 and the number of revolutions N of the belt motor that determines the speed of the belt 501 o (Constant), the calculation is performed using the following formula (1) (S01).

number

[0051] As a prerequisite for the rotary valve control unit 201b to operate the fuel supply system 100 according to this embodiment, it is necessary that the fuel supplied via the rotary valve 47 does not stagnate at a destination. To satisfy this, the rotation speed N of the belt motor 505 is set to 0.05 so as to satisfy the formulas (2) and (3). o It is sufficient to determine the following.

number

[0052] The rotary valve control section 201b receives a set value C from the central control room 2. set Then, the calculated actual fuel supply amount C real and setting value C set Then, the rotary valve control unit 201b adjusts the amount of fuel supplied from the bunker 13 to the fuel supply device 50 so that the difference between these values ​​becomes zero (approaching zero). To this end, the rotary valve control unit 201b adjusts the rotation speed N R / V (See Figure 7.)

[0053] Specifically, the actual fuel supply amount C real and setting value C set If they match (S03: Yes), the operation continues.

[0054] Actual fuel supply amount C real and setting value C setand the actual fuel supply amount C real is the set value C set If it is greater than (S04: Yes), the rotation speed N of the rotary valve 47 R / v The rpm is decreased (S05) and the process returns to step S01.

[0055] On the other hand, the actual fuel supply amount C real is the set value C set If it is smaller than (S04: No), the rotation speed N of the rotary valve 47 R / v The rpm is increased (S06) and the process returns to step S01.

[0056] The existing fuel supply system 100a for coal fuel can be modified to the fuel supply system 100 for biomass fuel according to this embodiment by the following steps.

[0057] As shown in FIG. 2, the crusher 5 is installed on the lower floor F1, and the fuel supply device 50 is installed on the upper floor F2. 1) Separate the downspout 52 and bunker 13 from the fuel supply machine 50. 2) The downspout 52 is divided and the lower downspout 52u is connected to the upper part of the fuel supply device 50. 3) Connect the rotary valve 47 to the top of the lower downspout 52u. 4) Connect the upper downspout 52t to the top of the rotary valve 47. 5) Connect the bunker 13 to the top of the upper downspout 52t.

[0058] According to this embodiment, the above steps 1) to 5) can be performed using the upper floor F2 as a scaffold, eliminating the need to prepare new scaffolding for the modification. Furthermore, the floor level of the fuel supply machine 50 remains unchanged, and the modification can be performed without lifting the fuel supply machine 50, reducing the cost of the modification work compared to the conventional example.

[0059] Furthermore, according to this embodiment, the fuel supplier 50 transports the fuel and measures the amount of fuel supplied, and the rotary valve 47 adjusts the amount of fuel supplied. This allows the central control room 2 to supply the pulverizer 5 with biomass fuel that satisfies the set value Cset determined in accordance with the operating load. Then, by supplying biomass fuel that satisfies the set value Cset from the pulverizer 5 to the boiler main body 3, the boiler equipment 1 can be operated at the operating load determined by the central control room 2.

[0060] The above-described embodiments are not intended to limit the present invention, and modifications that do not deviate from the spirit of the present invention are included in the present invention.

[0061] For example, when converting an existing fuel supply system 100a for coal fuel into a fuel supply system 100 for biomass fuel, it is only necessary to install the rotary valve 47 between the fuel supply device 50 and the bunker 13 while maintaining the level of the fuel supply device 50. Therefore, a different procedure from the above may be used, for example, by dividing the downspout 52 and connecting the rotary valve 47 between the lower downspout 52u and the upper downspout 52t in advance, and then integrating them and installing them above the fuel supply device 50.

[0062] Furthermore, even if there is a coal gate at the connection between the bunker 13 and the downspout 52, the fuel supply system according to this embodiment can be applied. [Explanation of symbols]

[0063] 1: Boiler equipment 2: Central control room 3: Boiler body 5: Crusher 7:Powdered fuel supply pipe 9: Burner 11: Biomass silo 13: Banka 15: Hot air supply pipe 17 :Primary ventilation fan 19: Air preheater 21: Gas recirculation ventilator 23: Electrostatic precipitator 25: Denitration equipment 27: Induced draft fan 29: Desulfurization equipment 31: Chimney 42: Grinding table 43: Crushing roller 44: Rotary separator 45: Lower piping 47: Rotary valve 47a: Seal air piping 47a1: Seal air valve 47b: Valve motor 49: Upper piping 50: Fuel supply machine 52: Downspout 52t: Upper downspout 52u: Lower downspout 100: Fuel supply system for biomass fuel 100a: Fuel supply system for coal fuel 100b: Fuel supply system for biomass fuels 200: Valve control device 201: Processor 201a: Supply amount calculation section 201b: Rotary valve control section 202:RAM 203:ROM 204: HDD 205: Input I / F 206: Output I / F 207: Communication I / F 208: Bus 211: Input device 212: Display 501: Belt 502: Drive rotor 503: Driven roller 504: Load cell 505: Belt motor Creal: Fuel supply amount Cset: setting value F1: Lower floor F2: Upper floor S01: Step S02: Step ΔH: Height

Claims

1. A fuel supply system for supplying fuel to a boiler facility, a bunker for storing solid fuel; a fuel supplier that supplies the solid fuel to a pulverizer that pulverizes the solid fuel; a downspout consisting of a pipe connecting the bunker and the fuel supply machine; A rotary valve; Equipped with the downspout is divided into an upper downspout and a lower downspout, the lower downspout is connected to an upper portion of the fuel supply device, the rotary valve is connected to an upper portion of the lower downspout, the upper downspout is connected to an upper portion of the rotary valve, and the bunker is connected to an upper portion of the upper downspout.

2. 2. The fuel supply system of claim 1, A fuel supply system, characterized in that the solid fuel is a biomass fuel.

3. 2. The fuel supply system of claim 1, a valve motor that rotates the rotary valve; a valve control device that controls the rotational speed of the valve motor; A fuel supply system further comprising:

4. A fuel supply system according to any one of claims 1 to 3; a boiler body to which fuel is supplied from the pulverizer; A boiler facility comprising:

5. 4. A method for operating a fuel supply system according to claim 3, which supplies fuel to a boiler, comprising: The valve control device includes: calculating an actual amount of fuel supplied from the fuel supplier to the pulverizer; a step of acquiring a set value according to an operating load of the boiler, comparing the set value with the actual supply amount, and controlling the rotation speed of the valve motor so that the difference approaches zero; A method for operating a fuel supply system, comprising:

6. A method for retrofitting a fuel supply system for converting a coal fuel supply system into a biomass fuel supply system, comprising: The fuel supply system for coal fuel is a pulverizer for pulverizing the coal fuel; a fuel supplier that supplies the coal fuel to the pulverizer; a bunker for storing the coal fuel; a downspout consisting of a pipe connecting the bunker and the fuel supply machine; Equipped with The method for modifying a fuel supply system includes: separating the downspout and the bunker from the fuel supply machine; Dividing the downspout into upper and lower parts, and designating the upper part as an upper downspout and the lower part as a lower downspout; connecting the lower downspout to an upper portion of the fuel supply machine; connecting a rotary valve to an upper portion of the lower downspout; connecting the upper downspout to an upper portion of the rotary valve; connecting the bunker to an upper portion of the upper downspout; 1. A method for modifying a fuel supply system, comprising:

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