Boiler system and boiler system operation method

Abstract

The purpose is to detect blockages even if a blockage occurs in any of the multiple solid fuel supply lines. [Solution] The power plant comprises a boiler 51 having a plurality of burners 52, a solid fuel crushing device for crushing solid fuel, a first distribution channel 61 and a second distribution channel 62 for supplying the crushed solid fuel together with a transport gas to each burner 52, a blower for adjusting the flow rate of the transport gas supplied to the burners 52, a sensor 65 provided in the first distribution channel 61 and the second distribution channel 62 for detecting the pressure and / or temperature of the first distribution channel 61 and the second distribution channel 62, a blockage detection unit for detecting blockage of the first distribution channel 61 or the second distribution channel 62 based on information detected by the sensor 65, and a transport gas control unit that controls the blower so as to increase the flow rate of the transport gas supplied to the burners 52 when the blockage detection unit 55 detects blockage of the first distribution channel 61 or the second distribution channel 62.

Description

Technical Field

[0001] The present disclosure relates to a boiler system and a method for operating a boiler system.

Background Art

[0002] Conventionally, solid fuels such as biomass fuel and coal are pulverized into fine powder within a predetermined particle size range by a pulverizer (mill) and supplied to a combustion device. The mill sandwiches the solid fuel input to the pulverizing table between the pulverizing table and the pulverizing roller and pulverizes it. Among the pulverized solid fuel that has become fine powder, the fine powder fuel within the predetermined particle size range is selected by a classifier and conveyed to a boiler by a conveying gas (primary air) supplied from the outer periphery of the pulverizing table, and burned in a combustion device. In a thermal power generation plant, steam is generated by heat exchange with combustion gas generated by burning fine powder fuel in a boiler, and the steam rotates and drives a steam turbine, and power generation is performed by rotating and driving a generator connected to the steam turbine.

[0003] As a device including a mill and a boiler, for example, the device described in Patent Document 1 is known. Patent Document 1 describes a pulverized coal-fired boiler including a mill to which coal is supplied from a coal feeder via a coal supply pipe and mill inlet air is sent from a mill inlet air duct, and a boiler furnace having a burner to which pulverized coal is supplied from the mill via a pulverized coal pipe. In this boiler, a pulverized coal pipe differential pressure gauge, a mill outlet air thermometer, and a mill outlet air pressure gauge are provided in the pulverized coal pipe.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A two-phase solid-gas flow, a mixture of pulverized fuel and primary air, circulates through the flow path connecting the mill and the boiler. Blockages due to the pulverized fuel can occur in this flow path. Since blockages can cause various problems, such as the inability to continue boiler operation, it is necessary to detect these blockages. One possible method for detecting blockages is to detect the pressure difference between the mill outlet and the boiler furnace pressure, and then detect the blockage based on this pressure difference.

[0006] A boiler system is known in which multiple flow paths connect the mill and the boiler. In such a boiler system, depending on the type of solid fuel (e.g., biomass fuel), only some of the flow paths may become blocked. Even if only some of the flow paths become blocked, leaving the blockage unaddressed can affect the transport of solid fuel in the other flow paths and potentially lead to blockages in those other flow paths as well. Therefore, it is necessary to detect the blockage.

[0007] However, if only some of the multiple flow paths become blocked, the differential pressure between the mill outlet and the boiler furnace may not fluctuate sufficiently. For this reason, the method of monitoring the differential pressure (pulverized coal differential pressure) between the mill outlet and the boiler furnace, as disclosed in Patent Document 1, may not be able to detect a situation where only some of the multiple flow paths are blocked.

[0008] This disclosure has been made in view of these circumstances and aims to provide a boiler system and a method for operating the boiler system that can detect blockages even when blockages occur in some of the flow paths among multiple solid fuel supply lines. [Means for solving the problem]

[0009] To solve the above problems, the boiler system and the operating method of the boiler system of this disclosure employ the following means. A boiler system according to one aspect of the present disclosure includes: a boiler having a plurality of burners that burn crushed solid fuel to form a flame; a solid fuel crushing device for crushing solid fuel to be supplied to each of the burners; a plurality of solid fuel supply lines for supplying the crushed solid fuel together with a transport gas to each of the burners; a transport gas flow rate adjustment unit for adjusting the flow rate of the transport gas supplied to the burners via the solid fuel supply lines; a detection unit provided in each of the solid fuel supply lines for detecting the pressure and / or temperature of the solid fuel supply line; a blockage detection unit for detecting blockage of the solid fuel supply line based on information detected by the detection unit; and a transport gas control unit that controls the transport gas flow rate adjustment unit so as to increase the flow rate of the transport gas supplied to the burners when the blockage detection unit detects blockage of the solid fuel supply line.

[0010] A method for operating a boiler system according to one aspect of the present disclosure is a method for operating a boiler system, the boiler system comprising: a boiler having a plurality of burners that burn crushed solid fuel to form a flame; a solid fuel crushing device for crushing solid fuel to be supplied to each of the burners; a plurality of solid fuel supply lines for supplying the crushed solid fuel together with a transport gas to each of the burners; and a transport gas flow rate adjustment unit for adjusting the flow rate of the transport gas supplied to the burners via the solid fuel supply lines, the method comprising: a detection step for detecting the pressure and / or temperature of the solid fuel supply line using a detection unit provided in each of the solid fuel supply lines; a blockage detection step for detecting blockage of the solid fuel supply line based on the information detected in the detection step; and a transport gas control step for controlling the transport gas flow rate adjustment unit so as to increase the flow rate of the transport gas supplied to the burners when blockage of the solid fuel supply line is detected in the blockage detection step. [Effects of the Invention]

[0011] Even if a blockage occurs in some of the multiple solid fuel supply lines, the blockage can be detected. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing a power plant according to one embodiment of the present disclosure. [Figure 2] Figure 1 is a schematic diagram showing the fuel supply system of the power plant. [Figure 3] This is a block diagram showing the control unit installed in the power plant shown in Figure 1. [Figure 4] Figure 1 is a graph showing how the control unit installed in the power plant detects blockages. [Figure 5] This diagram illustrates the flow pattern of granular solids contained in a solid-gas two-phase flow, showing the granular solids in a state of uniform flow. [Figure 6] This diagram illustrates the flow pattern of granular solids contained in a two-phase solid-gas flow, with the granular solids representing the state of bottom flow in a pipe. [Figure 7] This diagram illustrates the flow mode of granular solids contained in a solid-gas two-phase flow, where the granular solids are in a state of compression and rarefaction flow. [Figure 8] This diagram illustrates the flow pattern of granular solids contained in a two-phase solid-gas flow, showing a collective flow state of the granular solids. [Figure 9] This diagram shows the flow mode of granular solids contained in a solid-gas two-phase flow, where the granular solids are in a plugged flow state. [Figure 10] This diagram shows the flow mode of granular solid contained in a solid-gas two-phase flow, where the granular solid is in a partial flow state. [Figure 11] This is a timing chart showing the processing performed by the control unit installed in the power plant shown in Figure 1. [Modes for carrying out the invention]

[0013] An embodiment of the boiler system and the method of operating the boiler system relating to this disclosure will be described below with reference to the drawings.

[0014] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The power generation plant 1 according to this embodiment includes a solid fuel pulverizer 100 and a boiler 51. In the following description, "upward" refers to the vertically upward direction, and "upper" such as the upper part or the upper surface indicates the vertically upper part. Similarly, "downward" indicates the vertically lower part, and the vertical direction includes an error and is not strict.

[0015] The solid fuel pulverizer 100 of this embodiment is, as an example, a device that pulverizes solid fuels such as biomass fuel and coal, generates pulverized fuel, and supplies it to the burner (combustion device) 52 of the boiler 51. The power generation plant 1 including the solid fuel pulverizer 100 and the boiler 51 shown in FIG. 1 includes one solid fuel pulverizer 100, but may also be a system including a plurality of solid fuel pulverizers 100 corresponding to the plurality of burners 52 provided in the boiler 51.

[0016] The solid fuel pulverizer 100 of this embodiment includes a mill (pulverizing section) 10, a bunker (storage section) 20, a coal feeder (fuel supply machine) 21, a blower section (transport gas supply section) 30, a state detection section 40, and a control section 50.

[0017] The mill 10 that pulverizes solid fuels such as coal and biomass fuel supplied to the boiler 51 into pulverized fuel, which is finely powdered solid fuel, may be in a form that pulverizes only coal, a form that pulverizes only biomass fuel, or a form that pulverizes biomass fuel together with coal. Here, biomass fuel is a renewable bio-derived organic resource. For example, it includes thinned wood, waste wood, driftwood, grasses, biological waste, sludge, and recycled fuels (pellets and chips) made from these, and is not limited to what is presented here. Since biomass fuel takes in carbon dioxide during the growth process of biomass, it is considered carbon-neutral and does not emit carbon dioxide, which is a global warming gas, and thus its utilization is being variously studied.

[0018] The mill 10 comprises a housing 11, a grinding table 12, grinding rollers 13, a reduction gear (drive transmission unit) 14, a mill motor (drive unit) 15 connected to the reduction gear 14 and rotatingly driving the grinding table 12, a rotary classifier (classification unit) 16, a coal supply pipe (supply unit) 17, and a classifier motor 18 that rotately drives the rotary classifier 16. The housing 11 is formed in a cylindrical shape extending vertically and is a casing that houses the crushing table 12, the crushing rollers 13, the rotary classifier 16, and the coal supply pipe 17. A coal supply pipe 17 is installed in the center of the ceiling portion 42 of the housing 11. This coal supply pipe 17 supplies solid fuel, which has been guided from the bunker 20 via the coal feeder 21, into the housing 11. It is positioned vertically at the center of the housing 11, and its lower end extends into the interior of the housing 11.

[0019] A reduction gear 14 is installed near the bottom surface 41 of the housing 11, and a grinding table 12, which rotates due to the driving force transmitted from a mill motor 15 connected to this reduction gear 14, is rotatably positioned there. The crushing table 12 is a circular member in plan view, and is positioned so that the lower ends of the coal supply pipe 17 face each other. The upper surface of the crushing table 12 may have a sloping shape, for example, with the center being lower and the outer surface becoming higher towards the outside, and the outer circumference being bent upward. The coal supply pipe 17 supplies solid fuel (for example, coal or biomass fuel in this embodiment) from above to the crushing table 12 below, and the crushing table 12 crushes the supplied solid fuel by sandwiching it between the crushing rollers 13.

[0020] When solid fuel is fed from the coal supply pipe 17 toward the center of the crushing table 12, the centrifugal force from the rotation of the crushing table 12 guides the solid fuel toward the outer periphery of the crushing table 12, where it is crushed between the crushing table 12 and the crushing rollers 13. The crushed solid fuel is blown upward by the conveying gas (hereinafter sometimes referred to as primary air) introduced from the conveying gas passage (hereinafter sometimes referred to as primary air passage) 110 and guided toward the rotary classifier 16.

[0021] The outer circumference of the grinding table 12 is provided with an outlet (not shown) that allows primary air flowing in from the primary air passage 110 to flow out into the space above the grinding table 12 inside the housing 11. A swirling blade (not shown) is installed at the outlet, which imparts a swirling force to the primary air blown out from the outlet. The primary air, given a swirling force by the swirling blade, becomes an airflow with a swirling velocity component, which transports the solid fuel ground on the grinding table 12 to the rotary classifier 16 located above the housing 11. Of the ground solid fuel, those larger than a predetermined particle size are classified by the rotary classifier 16, or they fall without reaching the rotary classifier 16 and are returned to the grinding table 12, where they are ground again between the grinding table 12 and the grinding roller 13.

[0022] The crushing roller 13 is a rotating body that crushes the solid fuel supplied from the coal supply pipe 17 onto the crushing table 12. The crushing roller 13 is pressed against the upper surface of the crushing table 12 and works in cooperation with the crushing table 12 to crush the solid fuel. Although only one grinding roller 13 is shown as a representative example in Figure 1, multiple grinding rollers 13 are arranged at regular intervals in the circumferential direction to press against the upper surface of the grinding table 12. For example, three grinding rollers 13 are arranged at equal intervals in the circumferential direction with a 120° angle interval on the outer circumference. In this case, the parts of the three grinding rollers 13 that contact (press) the upper surface of the grinding table 12 are at equal distances from the rotational axis of the grinding table 12.

[0023] The crushing roller 13 is capable of vertical oscillation and displacement by the journal head 45 and is supported so as to be able to move closer to and further away from the upper surface of the crushing table 12. When the crushing table 12 rotates, the crushing roller 13 rotates along with the crushing table 12 as the crushing table 12 rotates, receiving a rotational force from the crushing table 12. When solid fuel is supplied from the coal supply pipe 17, the solid fuel is pressed and crushed between the crushing roller 13 and the crushing table 12. This pressing force is called the crushing load.

[0024] The support arm 47 of the journal head 45 is supported by a support shaft 48 whose intermediate portion is aligned horizontally, allowing the crushing roller 13 to swing and displace vertically around the support shaft 48 on the side surface of the housing 11. A pressing device (crushing load application unit) 49 is provided at the upper end of the support arm 47, which is vertically above it. The pressing device 49 is fixed to the housing 11 and applies a crushing load to the crushing roller 13 via the support arm 47, etc., so as to press the crushing roller 13 against the crushing table 12. The crushing load is applied, for example, by a hydraulic cylinder (not shown) that is operated by the pressure of hydraulic fluid supplied from a hydraulic device (not shown) installed outside the mill 10. Alternatively, the crushing load may be applied by the repulsive force of a spring (not shown).

[0025] The reduction gear 14 is connected to the mill motor 15 and transmits the driving force of the mill motor 15 to the grinding table 12, causing the grinding table 12 to rotate around its central axis.

[0026] The rotary classifier (classification unit) 16 is located on the upper part of the housing 11 and has a hollow, inverted conical shape. The rotary classifier 16 is equipped with a plurality of blades 16a extending vertically on its outer circumference. Each blade 16a is provided at a predetermined interval (equal intervals) around the central axis of the rotary classifier 16. The rotary classifier 16 is a device that classifies solid fuel crushed by the crushing table 12 and crushing rollers 13 (hereinafter, the crushed solid fuel will be referred to as "crushed fuel") into particles larger than a predetermined particle size (for example, 70-100 μm for coal) (hereinafter, crushed fuel with a particle size exceeding the predetermined particle size will be referred to as "coarse fuel") and particles smaller than the predetermined particle size (hereinafter, crushed fuel with a particle size smaller than the predetermined particle size will be referred to as "fine fuel"). The rotary classifier 16 is driven by a classifier motor 18 controlled by the control unit 50 and rotates around the coal supply pipe 17 around a cylindrical shaft (not shown) that extends vertically in the housing 11. Furthermore, a fixed classifier may be used as the classification unit, which has a fixed, hollow, inverted cone-shaped casing and a plurality of fixed swivel blades instead of blades 16a on the outer circumference of the casing.

[0027] The crushed fuel that reaches the rotary classifier 16 is subjected to a relative balance between the centrifugal force generated by the rotation of the blades 16a and the centripetal force from the airflow of the primary air. Larger diameter coarse fuel particles are knocked off by the blades 16a and returned to the crushing table 12 for further crushing, while the fine fuel particles are guided to the outlet port 19 located in the ceiling 42 of the housing 11. The fine fuel particles classified by the rotary classifier 16 are discharged from the outlet port 19 along with the primary air into the fine fuel supply channel (fine fuel supply pipe) 120 and supplied to the burner 52 of the boiler 51.

[0028] The coal supply pipe 17 is installed so as to extend vertically through the ceiling portion 42 of the housing 11, with its lower end extending into the interior of the housing 11, and supplies solid fuel fed from the top of the coal supply pipe 17 to the center of the crushing table 12. A coal feeder 21 is connected to the upper end of the coal supply pipe 17, and solid fuel is supplied to it.

[0029] The coal feeder 21 is connected to the bunker 20 by a downspout 24, which is a pipe extending vertically from the lower end of the bunker 20. A valve (coal gate, not shown) for switching the discharge state of solid fuel from the bunker 20 may be provided in the middle of the downspout 24. The coal feeder 21 comprises a conveying unit 22 and a coal feeder motor 23. The conveying unit 22 is, for example, a belt conveyor, which, driven by the coal feeder motor 23, conveys the solid fuel discharged from the lower end of the downspout 24 to the upper part of the coal supply pipe 17 and feeds it into the mill. The amount of solid fuel supplied to the mill 10 is controlled, for example, by changing the rotational speed of the coal feeder motor 23 in response to a signal from the control unit 50, thereby adjusting the moving speed of the belt conveyor of the conveying unit 22.

[0030] Normally, primary air is supplied to the mill 10 to transport the pulverized fuel to the burner 52, and the pressure inside is higher than that of the coal feeder 21 and bunker 20. Inside the downspout 24 connecting the bunker 20 and the coal feeder 21, solid fuel is layered. This layer of solid fuel suppresses the backflow of primary air from the mill 10 towards the bunker 20 and ensures a sealing effect (material seal) to maintain the pressure inside the mill 10.

[0031] The blower unit 30 is a device that blows primary air into the housing 11 to dry the crushed fuel and to transport it to the rotary classifier 16. In this embodiment, the blower unit 30 includes a primary air fan (PAF) 31, a hot gas passage 30a, a cold gas passage 30b, a hot gas damper 30c, and a cold gas damper 30d in order to appropriately adjust the flow rate and temperature of the primary air blown into the housing 11.

[0032] In this embodiment, the hot gas flow path 30a supplies a portion of the air sent from the primary air ventilator 31 as hot gas that has been heated by passing it through the air preheater (heat exchanger) 34. A hot gas damper 30c is provided in the hot gas flow path 30a. The opening degree of the hot gas damper 30c is controlled by the control unit 50. The flow rate of the hot gas supplied from the hot gas flow path 30a is determined by the opening degree of the hot gas damper 30c. Furthermore, a shut-off damper (not shown) for blocking the flow of hot gas may be provided in the hot gas passage 30a. The opening and closing of the shut-off damper may be controlled by the control unit 50 or operated manually.

[0033] The cold gas passage 30b supplies a portion of the air discharged from the primary air ventilator 31 as cold gas at room temperature. A cold gas damper 30d is provided in the cold gas passage 30b. The opening degree of the cold gas damper 30d is controlled by the control unit 50. The opening degree of the cold gas damper 30d determines the flow rate of cold gas supplied from the cold gas passage 30b. Furthermore, a shut-off damper (not shown) for blocking the flow of cold gas may be provided in the cold gas passage 30b. The opening and closing of the shut-off damper may be controlled by the control unit 50 or operated manually.

[0034] In this embodiment, the flow rate of the primary air is the sum of the flow rate of the hot gas supplied from the hot gas channel 30a and the flow rate of the cold gas supplied from the cold gas channel 30b. The temperature of the primary air is determined by the mixing ratio of the hot gas supplied from the hot gas channel 30a and the cold gas supplied from the cold gas channel 30b, and is controlled by the control unit 50. Furthermore, the oxygen concentration in the primary air blown into the housing 11 from the primary air passage 110 may be adjusted by introducing and mixing a portion of the combustion gas discharged from the boiler 51 by, for example, a gas recirculation ventilator (not shown) into the hot gas supplied from the hot gas passage 30a. By adjusting the oxygen concentration in the primary air, for example, when using a highly flammable (easily ignited) solid fuel, it is possible to suppress the ignition of the solid fuel in the path from the mill 10 to the burner 52.

[0035] In this embodiment, the state detection unit 40 of the mill 10 measures or detects data which is then transmitted to the control unit 50. The state detection unit 40 in this embodiment is, for example, a differential pressure measuring means which measures the differential pressure of the mill 10 between the pressure at the point where primary air flows from the primary air passage 110 into the inside of the housing 11 and the pressure at the outlet port 19 where primary air and fine fuel are discharged from the inside of the housing 11 to the fine fuel supply pipe 120. The increase or decrease in this differential pressure of the mill 10 corresponds to an increase or decrease in the circulation amount of the crushing fuel that circulates between the vicinity of the rotary classifier 16 and the vicinity of the crushing table 12 inside the housing 11 due to the classification effect of the rotary classifier 16. In other words, by adjusting the rotational speed of the rotary classifier 16 in accordance with the differential pressure of the mill 10, the amount and particle size range of the fine fuel discharged from the outlet port 19 can be adjusted. This allows for a stable supply of a quantity of fine fuel corresponding to the amount of solid fuel supplied to the mill 10 to the burner 52 in the boiler 51, while maintaining the particle size of the fine fuel within a range that does not affect the combustibility of the solid fuel in the burner 52. Furthermore, the state detection unit 40 in this embodiment is, for example, a temperature measuring means, which detects the temperature of the primary air supplied into the housing 11 (primary air temperature at the mill inlet) and the temperature of the mixed gas of primary air and pulverized fuel at the outlet port 19 (primary air temperature at the mill outlet), and controls the air blower 30 so that the respective upper limits are not exceeded. Each upper limit temperature is determined considering the possibility of ignition according to the properties of the solid fuel. Note that the primary air is cooled inside the housing 11 as the pulverized fuel is dried and transported, so the primary air temperature at the mill inlet is, for example, around 300 degrees Celsius from room temperature, and the primary air temperature at the mill outlet is, for example, around 90 degrees Celsius from room temperature.

[0036] The control unit 50 is a device that controls each part of the solid fuel crushing apparatus 100. The control unit 50 may, for example, transmit a drive command to the mill motor 15 to control the rotation speed of the grinding table 12. The control unit 50, for example, transmits a drive command to the classifier motor 18 to control the rotational speed of the rotary classifier 16 and adjust the classification performance, thereby maintaining the particle size of the fine fuel within a range that does not affect the combustibility of the solid fuel in the burner 52, and stably supplying an amount of fine fuel corresponding to the amount of solid fuel supplied to the mill 10 to the burner 52. Furthermore, the control unit 50 can adjust the amount of solid fuel supplied to the mill 10 (coal supply amount) by, for example, transmitting a drive instruction to the coal feeder motor 23. Furthermore, the control unit 50 can adjust the flow rate and temperature of the primary air by controlling the opening of the hot gas damper 30c and the cold gas damper 30d by transmitting an opening instruction to the blower unit 30. Specifically, the control unit 50 controls the opening of the hot gas damper 30c and the cold gas damper 30d so that the flow rate of the primary air supplied into the housing 11 and the temperature of the primary air at the outlet port 19 (mill outlet primary air temperature) are set to predetermined values ​​corresponding to the amount of coal supplied for each type of solid fuel. Note that the control of the primary air temperature may also be performed with respect to the temperature at the mill inlet (mill inlet primary air temperature).

[0037] The control unit 50 is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions are stored in the storage medium in the form of a program, for example. The CPU reads this program into the RAM and performs information processing and calculations to realize the various functions. The program may be pre-installed in the ROM or other storage medium, provided in a state where it is stored in a computer-readable storage medium, or distributed via wired or wireless communication. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memory. HDDs may be replaced with solid-state disks (SSDs), etc.

[0038] Next, a boiler 51 that generates steam by burning fine fuel supplied from a solid fuel crushing device 100 will be described. The boiler 51 is equipped with a furnace 54 and a burner 52.

[0039] The burner 52 is a device that burns the pulverized fuel to form a flame using a mixture of pulverized fuel supplied from the pulverized fuel supply pipe 120 and primary air, and secondary air supplied by heating air (outside air) sent from the forced draft fan (FDF) 32 in the air preheater 34. The combustion of the pulverized fuel takes place in the furnace 54, and the high-temperature combustion gas is discharged to the outside of the boiler 51 after passing through heat exchangers such as evaporators, superheaters, and economizers (not shown).

[0040] The combustion gas discharged from the boiler 51 undergoes predetermined treatment in environmental equipment (denitrification equipment, dust collector, desulfurization equipment, etc., not shown), and heat exchange with primary and secondary air takes place in the air preheater 34. The gas is then guided to the chimney (not shown) via the induced draft fan (IDF) 33 and released into the outside air. The air heated by the combustion gas in the air preheater 34 and sent out from the primary air fan 31 is supplied to the aforementioned hot gas flow path 30a. The feedwater to each heat exchanger of the boiler 51 is heated in an economizer (not shown), then further heated in an evaporator (not shown) and a superheater (not shown) to generate high-temperature, high-pressure superheated steam, which is sent to a steam turbine (not shown), which is the power generation unit, to rotate the steam turbine, and then rotates a generator (not shown) connected to the steam turbine to generate electricity, thus forming the power plant 1.

[0041] The solid fuels used may include coal, biomass fuel, and petroleum coke (PC). Furthermore, a combination of these solid fuels may be used.

[0042] Figure 2 shows the path of pulverized fuel from the mill 10 to the boiler 51. As shown in Figure 2, four pulverized fuel supply pipes 120 are connected to one mill 10. A temperature sensor 53 is provided at the upstream end of each pulverized fuel supply pipe 120, i.e., immediately after the outlet of the mill 10, to measure the mill outlet temperature. Each temperature sensor 53 measures the temperature of the mixed fluid of pulverized fuel and primary air (hereinafter sometimes referred to as "solid-gas two-phase flow") flowing through the corresponding pulverized fuel supply pipe 120. Each temperature sensor 53 transmits the measured information to the control unit 50 (see Figure 1). The temperature sensor 53 may be installed near the outlet port 19 of the mill 10 (in the internal space of the classifier 16) to measure the temperature common to each fine fuel supply pipe 120.

[0043] The downstream side of each pulverized fuel supply pipe 120 is connected to a distributor (branch) 60. In this embodiment, for example, pulverized fuel and primary air are supplied to each of the eight burners 52 of the boiler 51 by distribution from four distributors 60. That is, a distributor 60 distributes the pulverized fuel and primary air supplied from one pulverized fuel supply pipe 120 to two burners 52.

[0044] The eight burners 52 are located at the four corners of the furnace 54, which is rectangular in cross-sectional view, when it is virtually divided into two rectangles, left and right, as shown in Figure 2. Each of the four burners 52 on the left and right sides forms a swirling flame within the furnace 54. In other words, two swirling flames are formed within the furnace 54. Note that the form of the flame formed within the furnace 54 is not limited to a swirling flame.

[0045] A first distribution channel (branch channel) 61 and a second distribution channel (branch channel) 62 are provided between each distributor 60 and each burner 52. Each of the first distribution channel 61 and the second distribution channel 62 is connected to the primary air nozzle (not shown) of the corresponding burner 52. Thus, the first distribution channel 61 connects the distributor 60 to one of the two burners 52 (for example, the first burner 52a) that the distributor 60 distributes the fine fuel and primary air to. The second distribution channel 62 connects the distributor 60 to the other burner 52 (for example, the second burner 52b) that the distributor 60 distributes the fine fuel and primary air to.

[0046] In this embodiment, the pulverized fuel supply pipe 120, the distributor 60, and the distribution channels (specifically, the first distribution channel 61 and the second distribution channel 62) are included in the solid fuel supply line that guides a solid-gas two-phase flow from the mill 10 to the boiler 51 (specifically, the burner 52). That is, the solid fuel supply line includes a pulverized fuel supply pipe 120 connected to the solid fuel grinding device 100, a distributor 60 that branches the pulverized fuel supply pipe 120 into the first distribution channel 61 and the second distribution channel 62, and the first distribution channel 61 and the second distribution channel 62, which are branched by the distributor 60 and connected to the burner 52, respectively. The solid fuel supply line also connects the mill 10 and the boiler 51.

[0047] Furthermore, the burner 52 has a secondary air nozzle (not shown) that is provided to surround the primary air nozzle. The secondary air that is guided to the secondary air nozzle is supplied from the forced-air fan 32 shown in Figure 1.

[0048] The flow rates of pulverized coal and primary air directed to the primary air nozzle are controlled by the control unit 50. The flow rates of secondary air directed to the secondary air nozzle are also controlled by the control unit 50.

[0049] Furthermore, each distribution channel (in this embodiment, all first distribution channels 61 and all second distribution channels 62) is provided with a sensor (detection unit) 65. The sensor 65 detects the state of the solid-gas two-phase flow circulating in the distribution channel. Specifically, the sensor 65 detects the pressure and / or temperature of the distribution channel. That is, the sensor 65 may have a pressure sensor for detecting the pressure of the distribution channel and / or a temperature sensor for detecting the temperature of the distribution channel. Note that the temperature of the distribution channel may be the temperature of the components constituting the distribution channel (e.g., piping), or it may be the temperature of the solid-gas two-phase flow circulating in the distribution channel. The sensor 65 transmits the acquired information to the control unit 50.

[0050] As shown in Figure 3, the control unit 50 acquires the information detected by the sensor 65. Furthermore, the control unit 50 includes a blockage detection unit 55 that detects blockage of the first distribution channel 61 or the second distribution channel 62 based on information (pressure and / or temperature) detected by the sensor 65, and a conveying gas control unit 56 that controls the blower unit 30 so as to increase the flow rate of conveying gas (primary air) supplied to the burner 52 when the blockage detection unit 55 detects blockage of the first distribution channel 61 or the second distribution channel 62.

[0051] The control unit 50 may also include a solid fuel control unit 57 instead of the transport gas control unit 56. When the blockage detection unit 55 detects a blockage in the first distribution channel 61 or the second distribution channel 62, the solid fuel control unit 57 controls the amount of pulverized fuel supplied to the burner 52 to decrease. For example, it controls the coal feeder motor 27 to adjust the amount of solid fuel supplied to the mill 10. Alternatively, when the blockage detection unit 55 detects a blockage in the first distribution channel 61 or the second distribution channel 62, the solid fuel control unit 57 may control the classifier motor 18 to increase the rotational speed of the classifier 16, thereby reducing the amount of pulverized fuel supplied to the burner 52.

[0052] Furthermore, the control unit 50 may have both a transport gas control unit 56 and a solid fuel control unit 57.

[0053] Next, the method for detecting blockage in the blockage detection unit 55 will be explained using Figure 4. Figure 4 shows an example in which the sensor 65 detects pressure. In Figure 4 (a), (b), and (c), the vertical axis shows the pressure detected by the sensor 65, and the horizontal axis shows time.

[0054] As shown in Figures 4(a) and (b), the blockage detection unit 55 detects a blockage in the distribution piping (first distribution channel 61 or second distribution channel 62) when the pressure and / or temperature detected by the sensor 65 remain outside a predetermined range (a range that is below the upper threshold and above the lower threshold) for a first predetermined time or longer. (a) shows a case where a blockage occurs downstream of the sensor 65 and the pressure exceeds the upper threshold, while (b) shows a case where a blockage occurs upstream of the sensor 65 and the pressure falls below the lower threshold. The upper threshold may be, for example, 3 kPa higher than the pressure of the boiler 51 (more specifically, the pressure inside the furnace 54 of the boiler 51). The lower threshold may be, for example, 0.1 kPa higher than the pressure of the boiler 51 (more specifically, the pressure inside the furnace 54 of the boiler 51). In other words, the predetermined range may be a range of 3 kPa or less higher than the pressure of the boiler 51 and 0.1 kPa or more higher than the pressure of the boiler 51. The pressure of the boiler 51 may be negative pressure (e.g., -0.1 kPa) or positive pressure. Furthermore, the first predetermined time may be, for example, 5 seconds.

[0055] Furthermore, as shown in Figure 4(c), the blockage detection unit 55 detects a blockage (or signs of blockage) in the distribution piping (first distribution channel 61 or second distribution channel 62) if the pressure and / or temperature detected by the sensor 65 falls outside the predetermined range multiple times (five times in this embodiment) during the second predetermined time. Note that Figure 4(c) shows an example where the value falls outside the predetermined range due to exceeding the upper threshold. The second predetermined time may be, for example, 15 seconds, which is longer than the first predetermined time.

[0056] Next, the flow patterns of the solid-gas two-phase flowing through the first distribution channel 61 or the second distribution channel 62 will be explained using Figures 5 to 10. Figures 5 to 7 show a state in which solid particles (fine fuel F in this embodiment) contained in a solid-gas two-phase flow are in a suspended motion. Suspension motion is a state in which solid particles (fine fuel F in this embodiment) and gas (primary air G in this embodiment) are mixed and flowing together. The pressure loss in a solid-gas two-phase flow in a state in which solid particles are in a suspended motion is almost the same as the pressure loss when only gas is flowing. Also, in a state in which solid particles are in a suspended motion, the movement velocity of the gas and the movement velocity of the solid particles are approximately equal. That is, the slip velocity (the difference in movement velocity between the gas and the solid particles) is approximately zero. Figure 5 shows a homogeneous flow state in which solid particles are almost uniformly dispersed in a gas. Figure 6 shows a bottom-of-pipe flow state in which solid particles are concentrated towards the lower side of the flow path. Figure 7 shows a density-sparse flow state in which the concentration of solid particles has a distribution of varying concentrations along the flow direction.

[0057] Figures 8 to 10 show a state in which solid particles (fine fuel F in this embodiment) contained in a solid-gas two-phase flow are undergoing collective flow. Collective flow is a state in which a group of solid particles (fine fuel F in this embodiment) flows along the lower part of the flow path. The pressure loss in a solid-gas two-phase flow when solid particles are undergoing collective flow is greater than the pressure loss when only gas is flowing or when solid particles (fine fuel F in this embodiment) are in a floating motion. In addition, when solid particles are undergoing collective flow, the gas velocity is greater than the solid particle velocity. Figure 8 shows a collective flow state in which solid particles flow as granular groups divided in the flow direction. Figure 9 shows a plugged flow state in which groups of solid particles block the cross-section inside the pipe. Figure 10 shows a partial flow state in which solid particles accumulate on the lower side of the flow path, and solid particles flow only in the upper part.

[0058] In this embodiment, the blockage detection unit 55 determines that a blockage or a precursor to a blockage has occurred when solid particles contained in the solid-gas two-phase flow are flowing together. The control unit 50 then performs control (blockage response processing) to resolve the blockage or suppress the occurrence of a blockage, using the transport gas control unit 56 and / or the solid fuel control unit 57.

[0059] Next, the blockage response process performed by the control unit 50 of this embodiment will be explained using the timing chart in Figure 11. Figure 11(a) shows the change in detected pressure over time. Figure 11(b) shows the change in detected temperature over time. Figure 11(c) shows the change in the amount of solid fuel supplied to the burner 52 over time. Figure 11(d) shows the change in the flow rate of primary air to the burner 52 over time. Furthermore, in (a) and (b), 1 indicates the change in detected pressure or temperature detected by the sensor 65 corresponding to the first burner 52a. Similarly, 2, 3, and 4 indicate the changes in detected pressure or temperature detected by the sensors 65 corresponding to the second burner 52b, third burner 52c, and fourth burner 52d, respectively. The first burner 52a, the second burner 52b, the third burner 52c, and the fourth burner 52d are four burners 52 arranged in the longitudinal direction of the furnace 54, as shown in Figure 2, and are provided in order from one side to the other in the longitudinal direction.

[0060] The example in Figure 11 shows an instance where blockage in the distribution channel is detected based solely on the pressure detected by sensor 65. In the example in Figure 11(a), only sensor 65 corresponding to the first burner 52a detects a pressure greater than the upper threshold, while sensors 65 corresponding to the other burners 52 detect a pressure below the upper threshold. In other words, the example in Figure 11 indicates that blockage has occurred only in the distribution channel connected to the first burner 52a.

[0061] As shown in Figure 11(a), at timing t0, the sensor 65 corresponding to the first burner 52a detects a pressure higher than the upper threshold (detection step). This is due to a change in the flow mode of the pulverized fuel flowing through the first distribution channel 61 (more specifically, the first distribution channel 61 connected to the first burner 52a) at this timing, which causes an increase in the pressure in the first distribution channel 61. In other words, t0 represents the timing when the flow mode of the pulverized fuel flowing through the first distribution channel 61 begins to change from floating motion to collective flow.

[0062] From t0 to t1, which is the second predetermined time after the start of the process, the pressure exceeds the upper limit threshold. Therefore, at timing t1, the control unit 50 detects the blockage of the first distribution channel 61 using the blockage detection unit 55 (see Figure 3) (blockage detection step). At timing t1, as shown in Figure 11(b), it can be seen that the temperature of the first distribution channel 61 has decreased below the lower limit threshold due to the blockage. As soon as the blockage detection unit 55 detects a blockage, the control unit 50 starts an improvement operation. Specifically, for example, as shown in (1) of Figures 11(c) and (d), the transport gas control unit 56 (see Figure 3) increases the primary air flow rate supplied to the first burner 52a (transport gas control process) (see Figure 11(d)). In this case, the amount of fine fuel supplied to the first burner 52a is not changed (see Figure 11(c)). As an improvement operation, as shown in (2) of Figures 11(c) and (d), the amount of solid fuel supplied to the first burner 52a may be reduced by the solid fuel control unit 57 (see Figure 3) (solid fuel control process) (see Figure 11(c)). In this case, the flow rate of primary air supplied to the first burner 52a is not changed (see Figure 11(d)). Furthermore, as another effective improvement operation, for example, as shown in (1) of Figure 11(d), the primary air flow rate supplied to the first burner 52a may be increased by the transport gas control unit 56 (see Figure 11(d)), while as shown in (2) of Figure 11(c), the amount of solid fuel supplied to the first burner 52a may be reduced by the solid fuel control unit 57 (see Figure 11(c)).

[0063] As shown in Figures 11(c) and 11(d), the improvement operation is carried out gradually between t1 and t2. The improvement operation is completed at t2. After that, the amount of primary air and solid fuel that were changed by the improvement operation are maintained.

[0064] As shown in Figure 11(a), at a certain time after the improvement operation is completed at t3 (t4), the pressure in the first distribution channel 61 continuously falls below the upper limit threshold. In this way, the control unit 50 terminates the blockage improvement process.

[0065] This embodiment provides the following effects and advantages. In this embodiment, a sensor 65 for detecting the pressure and / or temperature of the distribution channel is provided in each distribution channel (first distribution channel 61 and second distribution channel 62). In addition, a blockage detection unit 55 is provided to detect blockage of the flow in the distribution channel based on the information detected by the sensor 65. For example, if blockage occurs in the distribution channel due to pulverized fuel, the pressure will rise above normal levels upstream of the blockage location. On the other hand, the pressure will fall below normal levels downstream of the blockage location. Thus, when blockage occurs, the pressure in the distribution channel fluctuates compared to normal levels both upstream and downstream of the blockage location. Therefore, the blockage detection unit 55 can detect blockage based on the information (pressure) detected by the sensor 65.

[0066] Furthermore, if the primary air temperature at the mill outlet is higher than the ambient temperature, for example, if blockage occurs in the distribution channel due to fine fuel, the flow rate of primary air downstream of the blockage will decrease, causing the temperature to drop below normal levels and approach the ambient temperature. Thus, when blockage occurs, the temperature in the distribution channel fluctuates compared to normal conditions. For this reason, the blockage detection unit 55 can detect blockage based on the information (temperature) detected by the sensor 65.

[0067] In this embodiment, a sensor 65 is provided in each distribution channel. Therefore, even if a blockage occurs in any of the multiple distribution channels, the blockage can be detected. Furthermore, the distribution channel in which the blockage occurred can be identified.

[0068] Furthermore, in this embodiment, when the blockage detection unit 55 detects a blockage in the distribution channel, a conveying gas control unit 56 is provided to control the blowing unit 30 so as to increase the flow rate of primary air supplied to the burner 52. As a result, the proportion of gas (primary air) increases in the solid-gas two-phase flow circulating in the distribution channel. Therefore, the blockage of the distribution channel can be improved.

[0069] Furthermore, in this embodiment, when the blockage detection unit 55 detects a blockage in the distribution channel, a solid fuel control unit 57 is provided to control the coal feeder motor 27 so as to reduce the amount of fine fuel supplied to the burner 52. As a result, the proportion of solid (fine fuel) in the solid-gas two-phase flow circulating in the distribution channel becomes lower. Therefore, the blockage of the distribution channel can be improved.

[0070] Normally, even if there is no blockage in the distribution channel, the pressure and / or temperature detected by the sensor 65 may fluctuate temporarily due to a malfunction of the sensor 65 or the like. On the other hand, if a blockage occurs in the distribution channel, the pressure and / or temperature may fluctuate multiple times within a short period of time (first predetermined time), or the pressure and / or temperature may fluctuate continuously. In this embodiment, the blockage detection unit 55 detects a blockage in the distribution channel when the pressure and / or temperature detected by the sensor 65 falls outside a predetermined range multiple times (five times in this embodiment as an example) within a first predetermined time. As a result, if the pressure and / or temperature temporarily rise or fall due to a malfunction of the sensor 65, the blockage detection unit 55 will not detect a blockage. On the other hand, if the pressure and / or temperature fluctuate multiple times within a short period of time (first predetermined time), the blockage detection unit 55 will detect a blockage. Therefore, the blockage of the distribution channel can be detected more accurately.

[0071] Furthermore, in this embodiment, the blockage detection unit 55 detects a blockage in the distribution channel when the pressure and / or temperature detected by the sensor 65 remain outside a predetermined range for a second predetermined time or longer. As a result, if the pressure and / or temperature temporarily rise or fall due to a malfunction of the sensor 65, the blockage detection unit 55 will not detect a blockage. On the other hand, if the pressure and / or temperature fluctuate continuously multiple times, the blockage detection unit 55 will detect a blockage. Therefore, the blockage of the distribution channel can be detected more accurately.

[0072] In this embodiment, the detection unit detects blockage of the distribution channel when the pressure detected by the sensor 65 becomes 3 kPa or more higher than the pressure of the boiler 51. This allows for effective detection of blockage.

[0073] In this embodiment, the detection unit detects blockage of the distribution channel when the pressure detected by the sensor 65 falls to 0.1 kPa or less than the pressure of the boiler 51. This allows for effective detection of blockage.

[0074] This disclosure is not limited to the embodiments described above, and can be modified as appropriate without departing from its essence. For example, the solid fuel used is not limited to this disclosure and may include coal, biomass fuel, petroleum coke (PC), etc. Furthermore, a combination of these solid fuels may be used.

[0075] Furthermore, in the above embodiment, for example, a sensor (branch channel detection unit) 65 was provided in each first distribution channel 61 and each second distribution channel 62, and an example of detecting blockage based on the pressure detected by the sensor 65 was described, but this disclosure is not limited thereto. The sensor used for detecting blockage may be provided in any part of the pulverized fuel supply line. Therefore, for example, instead of sensor 65, a sensor (solid fuel supply path detection unit) 70 may be provided in each fine fuel supply pipe 120, as shown by the dashed lines in Figures 2 and 9, and blockage detection may be performed based on the pressure and / or temperature detected by the sensor 70. Alternatively, in addition to sensor 65, a sensor 70 may be provided in each fine fuel supply pipe 120, and blockage detection may be performed based on the pressure and / or temperature detected by both sensor 65 and sensor 70.

[0076] Furthermore, while the above embodiment describes an example in which blockage is detected based on pressure and / or temperature detected by sensors 65 provided in each first distribution channel 61 and each second distribution channel 62, the disclosure is not limited thereto. For example, each first distribution channel 61 and each second distribution channel 62 may be equipped with a flow sensor to measure the flow rate of the fine fuel circulating inside, and blockage may be detected based on the flow rate of the fine fuel detected by the flow sensor, in addition to pressure and temperature. Furthermore, for example, each first distribution channel 61 and each second distribution channel 62 may be equipped with a flow sensor to measure the flow rate of primary air circulating inside, and blockage may be detected based on the flow rate of primary air detected by the flow sensor, in addition to pressure and temperature. Furthermore, vibration sensors may be provided for each first distribution channel 61 and each second distribution channel 62 to measure vibrations, and blockages may be detected based on vibrations detected by these vibration sensors, in addition to pressure and temperature. Furthermore, sound sensors for measuring sound may be provided for each first distribution channel 61 and each second distribution channel 62, and blockages may be detected based on the sound detected by the vibration sensors in addition to pressure and temperature.

[0077] Furthermore, in the above embodiment, an example was described in which the blockage of each first distribution channel 61 and each second distribution channel 62 is improved by increasing the primary air flow rate and / or reducing the amount of fine fuel when the blockage detection unit 55 detects a blockage, but this disclosure is not limited thereto. For example, the blockage of each first distribution channel 61 and each second distribution channel 62 may be improved by supplying purge gas to each first distribution channel 61 and each second distribution channel 62. In other words, in this modified example, as shown by the dashed line in Figure 9, when the blockage detection unit 55 detects a blockage, the purge gas supply unit 80 may be activated to supply purge gas to each of the first distribution channels 61 and each of the second distribution channels 62. The location where the purge gas is supplied may be near the distributor 60 among each of the first distribution channels 61 and each of the second distribution channels 62.

[0078] The boiler system and the method of operating the boiler system described in the embodiments above can be understood, for example, as follows. A boiler system according to a first aspect of the present disclosure includes a boiler (51) having a plurality of burners (52) that burn crushed solid fuel to form a flame, a solid fuel crushing device (100) that crushes the solid fuel to be supplied to each of the burners (52), a plurality of solid fuel supply lines (61, 62) that supply the crushed solid fuel together with a transport gas to each of the burners (52), a transport gas flow rate adjustment unit (30) that adjusts the flow rate of the transport gas supplied to the burners (52) via the solid fuel supply lines (61, 62), and each of the solid fuel The system includes a detection unit (65) provided in the supply lines (61, 62) for detecting the pressure and / or temperature of the solid fuel supply lines (61, 62), a blockage detection unit (55) for detecting blockage of the solid fuel supply lines (61, 62) based on the information detected by the detection unit (65), and a transport gas control unit (56) for controlling the transport gas flow rate adjustment unit (30) to increase the flow rate of transport gas supplied to the burner (52) when the blockage detection unit (55) detects blockage of the solid fuel supply lines (61, 62).

[0079] In the above configuration, a detection unit for detecting the pressure and / or temperature of the solid fuel supply line is provided in each solid fuel supply line. Furthermore, a blockage detection unit is provided that detects blockages in the flow of the solid fuel supply line based on the information detected by the detection unit. For example, if a blockage occurs in the solid fuel supply line due to crushed solid fuel, the pressure will rise above normal levels upstream of the blockage. On the other hand, the pressure will fall below normal levels downstream of the blockage. Thus, when a blockage occurs, the pressure in the solid fuel supply line fluctuates compared to normal levels both upstream and downstream of the blockage. Therefore, the blockage detection unit can detect a blockage based on the information (pressure) detected by the detection unit. Furthermore, if the transport gas temperature is higher than the ambient temperature, for example, if a blockage occurs in a solid fuel supply line due to crushed solid fuel, the flow rate of the transport gas downstream of the blockage will decrease, causing the temperature to drop below normal levels and approach the ambient temperature. Thus, when a blockage occurs, the temperature of the solid fuel supply line fluctuates compared to normal conditions. Therefore, the blockage detection unit can detect the blockage based on the information (temperature) detected by the detection unit.

[0080] In the above configuration, a detection unit is provided in each solid fuel supply line. Therefore, even if a blockage occurs in any of the multiple solid fuel supply lines, the blockage can be detected. Furthermore, the solid fuel supply line in which the blockage occurred can be identified.

[0081] Furthermore, the above configuration includes a transport gas control unit that controls the transport gas flow rate adjustment unit so that the flow rate of the transport gas supplied to the burner increases when the blockage detection unit detects a blockage in the solid fuel supply line. As a result, the proportion of gas (transport gas) increases in the solid-gas two-phase flow circulating in the solid fuel supply line. Therefore, blockage in the solid fuel supply line can be improved.

[0082] Furthermore, blockage of a solid fuel supply line includes not only a state where the entire cross-section of the flow path of the solid fuel supply line is blocked by solid fuel, but also a state where only a part of the flow path is blocked by solid fuel. It also includes a state in which the solid-gas two-phase flow (solid-gas two-phase flow of conveying gas and pulverized solid fuel) flowing through the solid fuel supply line is flowing in a collective manner.

[0083] A boiler system according to a second aspect of the present disclosure includes a boiler (51) having a plurality of burners (52) that burn crushed solid fuel to form a flame, a solid fuel crushing device (100) that crushes the solid fuel to be supplied to each of the burners (52), a plurality of solid fuel supply lines (61, 62) that supply the crushed solid fuel together with a transport gas to each of the burners (52), a solid fuel adjustment unit (27) that adjusts the amount of crushed solid fuel supplied to the burners (52) via the solid fuel supply lines (61, 62), and each of the solid fuel The system includes a detection unit (65) provided in the fuel supply line (61, 62) for detecting the pressure and / or temperature of the solid fuel supply line (61, 62), a blockage detection unit (55) for detecting blockage of the solid fuel supply line (61, 62) based on the information detected by the detection unit (65), and a solid fuel control unit (57) that controls the solid fuel adjustment unit (27) to reduce the amount of crushed solid fuel supplied to the burner (52) when the blockage detection unit (55) detects blockage of the solid fuel supply line (61, 62).

[0084] In the above configuration, a detection unit for detecting the pressure and / or temperature of the solid fuel supply line is provided in each solid fuel supply line. Furthermore, a blockage detection unit is provided that detects blockages in the solid fuel supply line based on the information detected by the detection unit. For example, if a blockage occurs in a solid fuel supply line due to crushed solid fuel, the pressure will rise above normal levels upstream of the blockage. On the other hand, the pressure will fall below normal levels downstream of the blockage. Thus, when a blockage occurs, the pressure in the solid fuel supply line fluctuates compared to normal levels both upstream and downstream of the blockage. Therefore, the blockage detection unit can detect a blockage based on the information (pressure) detected by the detection unit. Furthermore, if the transport gas temperature is higher than the ambient temperature, for example, if a blockage occurs in a solid fuel supply line due to crushed solid fuel, the flow rate of the transport gas downstream of the blockage will decrease, causing the temperature to drop below normal levels and approach the ambient temperature. Thus, when a blockage occurs, the temperature of the solid fuel supply line fluctuates compared to normal conditions. Therefore, the blockage detection unit can detect the blockage based on the information (temperature) detected by the detection unit.

[0085] In the above configuration, a detection unit is provided in each solid fuel supply line. Therefore, even if a blockage occurs in any of the multiple solid fuel supply lines, the blockage can be detected. Furthermore, the solid fuel supply line in which the blockage occurred can be identified.

[0086] Furthermore, the above configuration includes a solid fuel control unit that controls the solid fuel adjustment unit to reduce the amount of crushed solid fuel supplied to the burner when the blockage detection unit detects a blockage in the solid fuel supply line. As a result, the proportion of solid (crushed solid fuel) in the solid-gas two-phase flow circulating through the solid fuel supply line becomes lower. Therefore, blockage in the solid fuel supply line can be improved.

[0087] Furthermore, blockage of a solid fuel supply line includes not only a state where the entire cross-section of the flow path of the solid fuel supply line is blocked by solid fuel, but also a state where only a part of the flow path is blocked by solid fuel. It also includes a state in which the solid-gas two-phase flow (solid-gas two-phase flow of conveying gas and pulverized solid fuel) flowing through the solid fuel supply line is flowing in a collective manner.

[0088] In a boiler system according to a third aspect of the present disclosure, in the first or second aspect described above, the blockage detection unit (55) detects a blockage in the solid fuel supply line (61, 62) when the pressure and / or temperature detected by the detection unit (65) falls outside a predetermined range multiple times during a first predetermined time and / or when the pressure and / or temperature detected by the detection unit (65) falls outside a predetermined range for a second predetermined time or longer.

[0089] Even if there is no blockage in the solid fuel supply line, the pressure and / or temperature detected by the detection unit may fluctuate temporarily due to a malfunction in the detection unit, etc. On the other hand, if a blockage occurs in the solid fuel supply line, the pressure and / or temperature will fluctuate multiple times within a short period of time (first predetermined time), or the pressure and / or temperature will fluctuate continuously. In the above configuration, the blockage detection unit detects a blockage in the solid fuel supply line when the pressure and / or temperature detected by the detection unit fall outside a predetermined range multiple times within a first predetermined time. As a result, if the pressure and / or temperature temporarily rise or fall due to a malfunction in the detection unit, the blockage detection unit will not detect a blockage. On the other hand, if the pressure and / or temperature fluctuate multiple times within a short period of time (first predetermined time), the blockage detection unit will detect a blockage. Therefore, blockages in the solid fuel supply line can be detected more accurately. The first predetermined time may be, for example, 15 seconds.

[0090] Furthermore, in the above configuration, the blockage detection unit detects a blockage in the solid fuel supply line when the pressure and / or temperature detected by the detection unit remain outside a predetermined range for a second predetermined time or longer. As a result, if the pressure and / or temperature temporarily rise or fall due to a malfunction in the detection unit, the blockage detection unit will not detect a blockage. On the other hand, if the pressure and / or temperature fluctuate continuously multiple times, the blockage detection unit will detect a blockage. Therefore, blockages in the solid fuel supply line can be detected more accurately. The second predetermined time may be, for example, 5 seconds.

[0091] A boiler system according to a fourth aspect of the present disclosure, in any of the first to third aspects described above, the solid fuel supply line (61, 62) has a solid fuel supply channel (120) connected to the solid fuel grinding device (100), a branching section (60) that branches the solid fuel supply channel (120) into a plurality of branching channels (61, 62), and a plurality of the branching channels (61, 62) that are branched by the branching section (60) and connected to each of the burners (52), and the detection unit (65) has a branching channel detection unit (65) provided in the branching channels (61, 62).

[0092] In the above configuration, the detection unit has a branch channel detection unit provided in the branch channel. This allows for the detection of pressure and / or temperature in the branch channel. Therefore, blockage of the branch channel can be detected.

[0093] In the fifth aspect of the present disclosure, the boiler system, in the fourth aspect, has a detection unit (65) which includes a solid fuel supply channel detection unit (70) provided in the solid fuel supply channel (120).

[0094] In the above configuration, the detection unit includes a solid fuel supply channel detection unit provided in the solid fuel supply channel. This allows for the detection of pressure / or temperature in the solid fuel supply channel. Therefore, blockage of the solid fuel supply channel detection unit can be detected.

[0095] In the boiler system according to the sixth aspect of this disclosure, in any of the first to fifth aspects, the detection unit (65) has a pressure sensor that detects the pressure of the solid fuel supply lines (61, 62).

[0096] In the above configuration, the detection unit has a pressure sensor that detects the pressure in the solid fuel supply line. This allows the pressure in the solid fuel supply line to be detected. Therefore, blockage of the solid fuel supply line can be detected based on the pressure.

[0097] In the boiler system according to the seventh aspect of this disclosure, in the sixth aspect described above, the blockage detection unit (55) detects a blockage in the solid fuel supply line (61, 62) when the pressure detected by the pressure sensor becomes 3 kPa or more higher than the pressure of the boiler (51).

[0098] In the above configuration, the detection unit detects a blockage in the solid fuel supply line when the pressure detected by the pressure sensor becomes 3 kPa or more higher than the boiler pressure. This allows for effective detection of blockages. Note that the boiler pressure may also refer to the pressure inside the furnace of the boiler.

[0099] In the eighth aspect of the present disclosure, the boiler system, in the sixth or seventh aspect, includes a blockage detection unit (55) that detects a blockage in the solid fuel supply line (61, 62) when the pressure detected by the pressure sensor falls to 0.1 kPa or less than the pressure of the boiler (51).

[0100] In the above configuration, the detection unit detects a blockage in the solid fuel supply line when the pressure detected by the pressure sensor falls to 0.1 kPa or less below the boiler pressure. This allows for effective detection of blockages.

[0101] In the boiler system according to the ninth aspect of this disclosure, in any of the first to eighth aspects, the detection unit (65) has a temperature sensor that detects the temperature of the solid fuel supply line (61, 62).

[0102] In the above configuration, the detection unit has a temperature sensor that detects the temperature of the solid fuel supply line. This allows the pressure of the solid fuel supply line to be detected. Therefore, blockage of the solid fuel supply line can be detected based on the temperature.

[0103] In the boiler system according to the tenth aspect of this disclosure, in any of the first to ninth aspects, the solid fuel is a biomass fuel.

[0104] In the above configuration, the solid fuel is biomass fuel. This allows for the detection of blockages in any of the multiple solid fuel supply lines in a boiler system that uses biomass fuel.

[0105] A boiler system according to the eleventh aspect of this disclosure, in any of the first to tenth aspects described above, includes a purge gas supply unit (80) that supplies purge gas to the solid fuel supply lines (61, 62) when the blockage detection unit (55) detects a blockage in the solid fuel supply lines (61, 62).

[0106] In the above configuration, when the blockage detection unit detects a blockage in the solid fuel supply line, a purge gas supply unit is provided to supply purge gas to the solid fuel supply line. As a result, when a blockage is detected, purge gas flows through the solid fuel supply line. Therefore, the blockage in the solid fuel supply line can be improved by the flowing purge gas.

[0107] A method for operating a boiler system according to a first aspect of the present disclosure is a method for operating a boiler system (1), the boiler system (1) comprising: a boiler (51) having a plurality of burners (52) that burn crushed solid fuel to form a flame; a solid fuel crushing device (100) that crushes the solid fuel supplied to each of the burners (52); a plurality of solid fuel supply lines (61, 62) that supply the crushed solid fuel together with a transport gas to each of the burners (52); and a transport gas that adjusts the flow rate of the transport gas supplied to the burners (52) via the solid fuel supply lines (61, 62). The system comprises a flow rate adjustment unit (30), a detection step in which a detection unit (65) provided in each of the solid fuel supply lines (61, 62) detects the pressure and / or temperature of the solid fuel supply lines (61, 62), a blockage detection step in which a blockage of the solid fuel supply lines (61, 62) is detected based on the information detected in the detection step, and a transport gas control step in which, if a blockage of the solid fuel supply lines (61, 62) is detected in the blockage detection step, the transport gas flow rate adjustment unit (30) controls the transport gas flow rate adjustment unit (30) so as to increase the flow rate of the transport gas supplied to the burner (52).

[0108] A method for operating a boiler system according to a second aspect of the present disclosure is a method for operating a boiler system (1), the boiler system (1) comprising: a boiler (51) having a plurality of burners (52) that burn crushed solid fuel to form a flame; a solid fuel crushing device (100) that crushes the solid fuel to be supplied to each of the burners (52); a plurality of solid fuel supply lines (61, 62) that supply the crushed solid fuel together with a transport gas to each of the burners (52); and a method for adjusting the amount of crushed solid fuel supplied to the burners (52) via the solid fuel supply lines (61, 62). The system includes a solid fuel adjustment unit (27), and comprises: a detection step in which a detection unit (65) provided in each of the solid fuel supply lines (61, 62) detects the pressure and / or temperature of the solid fuel supply lines (61, 62); a blockage detection step in which a blockage of the solid fuel supply lines (61, 62) is detected based on the information detected in the detection step; and a solid fuel control step in which, if a blockage of the solid fuel supply lines (61, 62) is detected in the blockage detection step, the system controls the solid fuel adjustment unit (27) so as to reduce the amount of pulverized solid fuel supplied to the burner (52). [Explanation of Symbols]

[0109] 1. Power plant 10 Mill (Grinding section) 11 Housing 12 Grinding Tables 13 Crushing rollers 14. Reducer (drive transmission unit) 15. Mill motor (drive unit) 16 Rotary classifier (classifying section) 16a blade 17 Coal feed pipe (supply section) 18 Classification motor 19 Exit Ports 20 Bunker (storage area) 21 Coal feeding machine (fuel supply machine) 22 Conveying section 23. Coal feeder motor 24 Downspout 30. Air blower unit (gas supply unit for transport) 30a Hot gas flow path 30b Cold gas flow path 30c thermal gas damper 30d Cold Gas Damper 31. Primary Air Fan (PAF) 32 Forced draft fan (FDF) 33. Induced Draft Fan (IDF) 34. Air preheater (heat exchanger) 40 State detection unit (temperature detection means, differential pressure detection means) 41 Bottom part 42 Ceiling section 45 Journal Heads 47 Support Arm 48 Support shaft 49. Pressing device (crushing load application section) 50 Control Unit 51 Boiler 52 Burner (combustion device) 52a First Burner 52b Second Burner 52c Third Burner 52d Burner No. 4 53 Temperature Sensor 54 Furnace 55 Blockage detection unit 56 Gas control unit for transport 57 Solid Fuel Control Unit 60-way splitter (branching section) 61. First distribution channel (branch channel) 62 Second distribution channel (branch channel) 65 Sensor (detection unit) 70 Sensor (Solid fuel supply path detection unit) 80 Purge gas supply unit 100 Solid Fuel Grinding Machine 110 Primary air passage (gas passage for transport) 120. Fine fuel supply channel (fine fuel supply pipe)

Claims

1. A boiler having multiple burners that burn crushed solid fuel to form a flame, A solid fuel crushing device for crushing the solid fuel supplied to each of the burners, Multiple solid fuel supply lines supply the pulverized solid fuel together with the transport gas to each of the burners, A conveying gas flow rate adjustment unit adjusts the flow rate of the conveying gas supplied to the burner via the solid fuel supply line, A detection unit is provided in each of the solid fuel supply lines for detecting the pressure and / or temperature of the solid fuel supply line, Based on the information detected by the detection unit, a blockage detection unit detects the blockage of the solid fuel supply line, A boiler system comprising: a blockage detection unit that detects a blockage in the solid fuel supply line, and a conveying gas control unit that controls the conveying gas flow rate adjustment unit to increase the flow rate of the conveying gas supplied to the burner.

2. A boiler having multiple burners that burn crushed solid fuel to form a flame, A solid fuel crushing device for crushing the solid fuel supplied to each of the burners, Multiple solid fuel supply lines supply the pulverized solid fuel together with the transport gas to each of the burners, A solid fuel adjustment unit that adjusts the amount of crushed solid fuel supplied to the burner via the solid fuel supply line, A detection unit is provided in each of the solid fuel supply lines for detecting the pressure and / or temperature of the solid fuel supply line, Based on the information detected by the detection unit, a blockage detection unit detects the blockage of the solid fuel supply line, A boiler system comprising: a solid fuel control unit that controls the solid fuel adjustment unit to reduce the amount of crushed solid fuel supplied to the burner when the blockage detection unit detects a blockage in the solid fuel supply line; and a solid fuel control unit.

3. The boiler system according to claim 1 or 2, wherein the blockage detection unit detects a blockage in the solid fuel supply line when the pressure and / or temperature detected by the detection unit falls outside a predetermined range multiple times during a first predetermined time and / or when the pressure and / or temperature detected by the detection unit falls outside a predetermined range for a second predetermined time or longer.

4. The solid fuel supply line comprises a solid fuel supply channel connected to the solid fuel crushing device, a branching section that branches the solid fuel supply channel into a plurality of branching channels, and a plurality of branching channels that are branched by the branching section and connected to each of the burners. The boiler system according to claim 1 or claim 2, wherein the detection unit is a branch channel detection unit provided in the branch channel.

5. The boiler system according to claim 4, wherein the detection unit is a solid fuel supply channel detection unit provided in the solid fuel supply channel.

6. The boiler system according to claim 1 or 2, wherein the detection unit has a pressure sensor for detecting the pressure of the solid fuel supply line.

7. The boiler system according to claim 6, wherein the blockage detection unit detects a blockage in the solid fuel supply line when the pressure detected by the pressure sensor becomes 3 kPa or more higher than the boiler pressure.

8. The boiler system according to claim 6, wherein the blockage detection unit detects a blockage in the solid fuel supply line when the pressure detected by the pressure sensor falls to a pressure 0.1 kPa lower than the boiler pressure.

9. The boiler system according to claim 1 or 2, wherein the detection unit has a temperature sensor for detecting the temperature of the solid fuel supply line.

10. The boiler system according to claim 1 or claim 2, wherein the solid fuel includes biomass fuel.

11. The boiler system according to claim 1 or 2, further comprising a purge gas supply unit that supplies purge gas to the solid fuel supply line when the blockage detection unit detects a blockage in the solid fuel supply line.

12. A method for operating a boiler system, The boiler system is A boiler having multiple burners that burn crushed solid fuel to form a flame, A solid fuel crushing device for crushing the solid fuel supplied to each of the burners, Multiple solid fuel supply lines supply the pulverized solid fuel together with the transport gas to each of the burners, The system includes a conveying gas flow rate adjustment unit that adjusts the flow rate of the conveying gas supplied to the burner via the solid fuel supply line, A detection step in which a detection unit provided in each of the solid fuel supply lines detects the pressure and / or temperature of the solid fuel supply line, A blockage detection step is performed to detect blockage in the solid fuel supply line based on the information detected in the above detection step, A method for operating a boiler system, comprising: a conveying gas control step, which controls the conveying gas flow rate adjustment unit to increase the flow rate of the conveying gas supplied to the burner when a blockage is detected in the blockage detection step of the solid fuel supply line; and a method for operating a boiler system.

13. A method for operating a boiler system, The boiler system is A boiler having multiple burners that burn crushed solid fuel to form a flame, A solid fuel crushing device for crushing the solid fuel supplied to each of the burners, Multiple solid fuel supply lines supply the pulverized solid fuel together with the transport gas to each of the burners, The system includes a solid fuel adjustment unit that adjusts the amount of crushed solid fuel supplied to the burner via the solid fuel supply line, A detection step in which a detection unit provided in each of the solid fuel supply lines detects the pressure and / or temperature of the solid fuel supply line, A blockage detection step is performed to detect blockage in the solid fuel supply line based on the information detected in the above detection step, A method for operating a boiler system, comprising: a solid fuel control step, in which, when a blockage in the solid fuel supply line is detected in the blockage detection step, the solid fuel adjustment unit is controlled to reduce the amount of crushed solid fuel supplied to the burner.

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