Input amount estimation device, power generation system, and fluidized bed boiler control method

Abstract

To provide an input estimation device and a power generation system that can accurately estimate the input of combustibles into a fluidized bed type boiler by using existing equipment.SOLUTION: An input estimation device 1B estimates the input of combustibles D into a fluidized bed type boiler 1A in a power generation system 1 for generating power by using steam generated by heat exchange with exhaust gas discharged from the fluidized bed type boiler 1A, and comprises: an input unit into which the amount and oxygen concentration of the exhaust gas, the amount and temperature of air flowing into the fluidized bed type boiler 1A, the temperature of feedwater supplied to the fluidized bed type boiler 1A, and the amount of the steam are input; and an estimation unit for estimating the amount of the combustibles on the basis of input values in the input unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an input amount estimation device for estimating the amount of combustible material to be input into a fluidized bed boiler, a power generation system, and a fluidized bed boiler control method, in a power generation system that generates electricity using steam produced by heat exchange with exhaust gas discharged from a fluidized bed boiler. [Background technology]

[0002] Conventionally, power generation systems equipped with a fluidized bed boiler that gasifies combustible materials such as biomass fuel using fluidized sand are known (see, for example, Patent Document 1). This power generation system generates electricity using steam produced by heat exchange with exhaust gas discharged from the fluidized bed boiler, and comprises a fluidized bed boiler and a steam turbine generator. The fluidized bed boiler generates steam using the heat of the exhaust gas, and the steam turbine generator generates electricity by rotating a turbine with the steam generated by the boiler.

[0003] In the power generation system described in Patent Document 1, biomass fuel containing wood chips is fed from an input hopper to a fluidized bed boiler via a screw feeder. At this time, a storage hopper is provided upstream of the input hopper to prevent bridging of the biomass fuel within the input hopper. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-70570 [Overview of the project] [Problems that the invention aims to solve]

[0005] The power generation system described in Patent Document 1 is a technology that prevents bridging of biomass fuel in the input hopper and quantitatively feeds biomass fuel into a fluidized bed boiler. However, because the weight of biomass fuel fed into the fluidized bed boiler fluctuates depending on the density and water content of the biomass fuel, it is not possible to accurately determine the amount of biomass fuel fed into the fluidized bed boiler. If the amount of biomass fuel fed into the boiler is unknown, the operating status of the fluidized bed boiler cannot be determined, which poses operational management problems.

[0006] While it is conceivable to install weight sensors on conveying equipment such as belt conveyors and screw feeders to track the amount of biomass fuel being used, there were problems such as difficulty in securing space for conveying equipment with weight sensors, and the excessive cost of introducing and maintaining new conveying equipment with built-in weight sensors.

[0007] Therefore, there is a need for an input amount estimation device, a power generation system, and a fluidized bed boiler control method that can accurately estimate the amount of combustible material to be input into a fluidized bed boiler using existing equipment. [Means for solving the problem]

[0008] The input amount estimation device according to the present invention uses steam generated by heat exchange with exhaust gas discharged from a fluidized bed boiler. With a steam turbine generator An input amount estimation device for estimating the amount of combustible material to be input into a fluidized bed boiler in a power generation system, comprising: an input unit into which the amount and oxygen concentration of exhaust gas, the amount and temperature of air flowing into the fluidized bed boiler, the temperature of the feedwater supplied to the fluidized bed boiler, and the amount of steam are input; and an estimation unit that estimates the amount of combustible material to be input based on the input values ​​of the input unit. The estimation unit performs the following: calculates the power generation efficiency based on the power output from the steam turbine generator, the amount of air and air temperature flowing into the fluidized bed boiler, the temperature of the feedwater supplied to the fluidized bed boiler, the amount of exhaust gas, and the amount of steam; calculates the lower heating value of the combustible material based on the calculated power generation efficiency, power generation, amount of exhaust gas and oxygen concentration, the amount of air and steam flowing into the fluidized bed boiler; and estimates the amount of combustible material to be input based on the calculated lower heating value, power generation efficiency, and power generation. .

[0009] Furthermore, the power generation system according to the present invention comprises the input amount estimation device, the fluidized bed boiler, and a power generation device that generates electricity using the steam produced by heat exchange with the exhaust gas discharged from the fluidized bed boiler. In addition, the fluidized bed boiler control method causes a computer to perform an estimation step of estimating the amount of combustible material to be input using the input amount estimation device, and a control step of controlling the operation of the fluidized bed boiler based on the input amount estimated in the estimation step.

[0010] The combustion efficiency and combustion conditions in a fluidized bed boiler depend heavily on the state of the combustible material being fed in and the furnace temperature of the fluidized bed boiler. Furthermore, the power generation efficiency in a power generation system that uses steam generated by heat exchange with exhaust gas discharged from a fluidized bed boiler depends heavily on the state of the exhaust gas and the amount of steam. Therefore, as in this configuration, if the estimation unit estimates the amount of combustible material to be fed in based on the amount and oxygen concentration of the exhaust gas, the amount and temperature of the air flowing into the fluidized bed boiler, the temperature of the feedwater supplied to the fluidized bed boiler, and the amount of steam, the amount of combustible material to be fed into the fluidized bed boiler can be accurately estimated. Based on the amount of combustible material estimated by this estimation unit, it becomes possible not only to understand the operating state of the fluidized bed boiler, but also to manage the quality and quantity of combustible material to be replenished in the input hopper. Furthermore, the amount of combustible material to be input can be calculated based on the power generated and the power generation efficiency obtained from the power generation device, as well as the lower heating value of the combustible material. Power generation efficiency is the ratio of power generated to the heat of the combustible material, calculated based on values ​​input to the input section, such as the amount and temperature of air flowing into the fluidized bed boiler, the temperature of the feedwater supplied to the fluidized bed boiler, the amount of exhaust gas, and the amount of steam. Therefore, by calculating the lower heating value of the combustible material, the amount of combustible material to be input into the fluidized bed boiler can be accurately estimated.

[0013] Furthermore, the estimation unit may estimate the amount of combustible material to be added using an approximation formula between the lower heating value and the theoretical value of the exhaust gas volume.

[0014] Under predetermined conditions where the composition, lower heating value, and ash content of combustible materials in a dry state are constant, we found that the relationship between the lower heating value and the theoretical exhaust gas volume can be approximated by a linear function. Therefore, by estimating the amount of combustible material to be input using an approximation formula between the lower heating value and the theoretical value of the exhaust gas volume, as in this configuration, the calculation speed can be increased.

[0015] Furthermore, the input unit may also receive input for the amount of water injected into the fluidized bed boiler.

[0016] Taking into account the water injection amount in this way, the input amount of combustible materials into the fluidized bed boiler can be accurately estimated.

[0017] Further, the combustible material may contain wood chips.

[0018] If the low calorific value of wood chips rises too much, there is a risk that clinkers, which are incineration ash in the form of lumps, will occur. Therefore, as described above, by grasping the low calorific value of wood chips and adjusting the mixing ratio of wood chips, etc., the occurrence of clinkers can be prevented.

Brief Description of the Drawings

[0019] [Figure 1] It is a diagram illustrating the configuration of the power generation system. [Figure 2] It is a block diagram of the input amount estimation device. [Figure 3] It is a diagram showing the relationship between the low calorific value and the theoretical exhaust gas amount. [Figure 4] It is a flowchart of the input amount estimation device. [Figure 5] It is a diagram showing the estimation result of the input amount.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the input amount estimation device, power generation system, and fluidized bed boiler control method according to the present invention will be described based on the drawings. The power generation system in this embodiment generates power using steam generated from a fluidized bed boiler. However, it is not limited to the following embodiments, and various modifications are possible without departing from the gist thereof.

[0021] 〔Power Generation System〕 As shown in Figure 1, the power generation system 1 comprises a fluidized bed furnace 2 including a hopper 5 and a conveyor belt 6, a boiler 3 including a feedwater device 8, a steam turbine generator 4 (an example of a power generation device), and a chimney 7. In this embodiment, the fluidized bed boiler 1A consists of the fluidized bed furnace 2 and the boiler 3, and the power generation system 1 includes the fluidized bed boiler 1A, the steam turbine generator 4, and the input amount estimation device 1B. The input amount estimation device 1B includes at least a program stored in hardware such as an HDD or memory as software to control the operation of the fluidized bed furnace 2, and is executed by a processor including a computer's ASIC, FPGA, CPU, or other hardware.

[0022] The fluidized bed furnace 2 comprises a sand layer 10 mainly composed of silica sand and a blower 11 that forces air into the sand layer 10. The sand layer 10 is located in the lower region of the fluidized bed furnace 2 and is heated to approximately 450°C to approximately 600°C to incinerate biomass fuel D (an example of combustible material) containing wood chips that is placed on top of the sand layer 10. The blower 11 is located below the sand layer 10 and supplies air to the sand layer 10 from below. In this embodiment, the biomass fuel D consists only of wood chips, but other organic materials such as sludge, garbage, and rice husks may also be mixed in.

[0023] Boiler 3 is located above fluidized bed furnace 2 and connected to it, generating steam using the heat from the exhaust gas discharged by fluidized bed furnace 2. A cooling water spray device 12 is provided in the upper region of boiler 3. The cooling water spray device 12 sprays cooling water, such as water, into the fluidized bed furnace 2 as needed to adjust the temperature of the sand layer 10. Water is supplied to boiler 3 from feedwater device 8, and steam is generated through heat exchange with the exhaust gas. Note that if it is not necessary to adjust the temperature of the sand layer 10, the cooling water spray device 12 may be omitted.

[0024] The steam turbine generator 4 is supplied with steam generated by the boiler 3, and the steam rotates the turbine to generate electricity. The exhaust gas from which heat has been recovered in the boiler 3 is cooled and de-drained before being discharged out of the system through the chimney 7.

[0025] The feedwater system 8 includes a condenser that cools and condenses the low-pressure wet steam discharged from the turbine outlet of the steam turbine generator 4, returning it to saturated water for storage, and a deaerator that deaerates the saturated water returned from the condenser to the boiler 3 by a pump.

[0026] Hopper 5 is supplied with wood chips (biomass fuel D) transported from a stockyard (not shown) by a wheel loader H, and temporarily stores the biomass fuel D. Hopper 5 sends a predetermined amount of the stored biomass fuel D to the conveyor belt 6. Since the conveyor belt 6 is not equipped with a weight sensor, the amount of biomass fuel D stored in hopper 5 is measured visually or by a level sensor, and the biomass fuel D is periodically replenished in hopper 5. Alternatively, water that seeps out from the biomass fuel D and accumulates at the bottom of hopper 5 may be supplied as cooling water.

[0027] The conveyor belt 6 transports the biomass fuel D received from the hopper 5 to the fluidized bed furnace 2 at a predetermined speed, and then feeds the biomass fuel D into the fluidized bed furnace 2. The chimney 7 discharges the exhaust gas, which has been removed from the boiler 3 and is free of harmful substances, to the outside.

[0028] Furthermore, the power generation system 1 of this embodiment includes a data acquisition unit 1C, which includes a thermocouple 18, an air measurement unit 20, an exhaust gas measurement unit 21, a feedwater measurement unit 22, a steam measurement unit 23, and a cooling water measurement unit 24, in order to acquire the data necessary for the input amount estimation device 1B to estimate the amount of biomass fuel D to be input to the fluidized bed boiler 1A (see also Figure 2).

[0029] The thermocouple 18 measures the temperature of the sand layer 10. The thermocouple 18 only needs to be able to measure the temperature of the sand layer 10, and it is preferable that multiple thermocouples 18 are provided in the sand layer 10, and the average of their measured values ​​is taken as the temperature of the sand layer 10. For example, three thermocouples 18 are provided at equal intervals so that they penetrate the side wall of the fluidized bed furnace 2 from the side of the fluidized bed furnace 2, with their tips inserted into the sand layer 10.

[0030] The air measurement unit 20 measures the amount of forced air Vp (kNm) supplied to the sand layer 10 via the blower 11.3 A forced air sensor measures the amount of secondary air Vs (kNm³) supplied to the upper region of the fluidized bed furnace 2 (lower region of the boiler 3), and the forced air temperature Tp (°C). 3 It includes a secondary air sensor that measures the air flow rate ( / h) and the secondary air temperature Ts (°C). The forced air sensor and secondary air sensor consist of known flow sensors for measuring the air flow rate and known temperature sensors for measuring the air temperature. The secondary air supplied to the upper region of the fluidized bed furnace 2 is introduced from multiple locations (five locations in this embodiment) at different heights along the vertical direction, and multiple inlets are provided at each location. For this reason, the secondary air sensors of the air measuring unit 20 may be provided at each inlet, or at five locations at different heights along the vertical direction.

[0031] The exhaust gas measurement unit 21 measures the amount of exhaust gas discharged by the fluidized bed furnace 2 (hereinafter referred to as the exhaust gas amount Ve(kNm)). 3 The system includes a known exhaust gas sensor that measures the amount of steam supplied from the feedwater device 8 to the boiler 3 (hereinafter referred to as feedwater temperature Tw (°C)). The feedwater measurement unit 22 includes a known temperature sensor that measures the temperature of the feedwater supplied from the feedwater device 8 to the boiler 3 (hereinafter referred to as feedwater temperature Tw (°C)). The feedwater measurement unit 22 may also include a known flow rate sensor that measures the flow rate of water supplied from the feedwater device 8 to the boiler 3. The steam measurement unit 23 includes a known steam measurement unit that measures the amount of steam supplied from the boiler 3 to the steam turbine generator 4 (hereinafter referred to as steam volume Vw (kNm)). 3 The cooling water measuring unit 24 includes a known flow sensor that measures the amount of cooling water sprayed into the fluidized bed furnace 2 (hereinafter referred to as the water injection amount Ww(t / h)).

[0032] The fluidized bed furnace 2 controls the combustion of biomass fuel D and generates exhaust gas by adjusting the temperature of the sand layer 10, the forced air supplied from the blower 11 and the secondary air supplied from the upper region, and the amount of water sprayed from the cooling water sprayer 12, Ww (t / h). The boiler 3 uses the thermal energy of the exhaust gas generated in the fluidized bed furnace 2 to boil water supplied to the boiler 3 from the feedwater device 8, generating high-pressure steam. This generated high-pressure steam is supplied to the steam turbine generator 4, which rotates the turbine to generate electricity. The exhaust gas from which thermal energy has been recovered in the boiler 3 is cooled and de-drained before being discharged out of the system via the chimney 7.

[0033] The operating conditions of the fluidized bed furnace 2 and boiler 3 are set so that the steam turbine generator 4 does not produce a predetermined amount of power, and high-pressure steam is generated in boiler 3. On the other hand, if an excess of high-pressure steam is generated and exceeds the predetermined amount of power, the shut-off valve 25 is opened and the excess high-pressure steam is discharged to the outside. The combustion efficiency and combustion conditions in the fluidized bed boiler 1A depend greatly on the condition of the biomass fuel D that is fed in and the furnace temperature of the fluidized bed boiler 1A. In addition, the power generation efficiency of the steam turbine generator 4, which generates electricity using steam produced by heat exchange with the exhaust gas discharged from the fluidized bed boiler 1A, depends greatly on the condition of the exhaust gas and the amount of steam.

[0034] As shown in Figure 2, the input amount estimation device 1B in this embodiment has an estimation unit 32 that estimates the input amount of biomass fuel D based on the exhaust gas amount Ve and exhaust gas oxygen concentration Oe, the forced air amount Vp and secondary air amount Vs, the forced air temperature Tp and secondary air temperature Ts, the feedwater temperature Tw, and the steam amount Vw. When the cooling water spray device 12 is operating, the estimation unit 32 estimates the input amount of biomass fuel D using the water injection amount Ww. To improve the estimation accuracy, it is preferable to add the soot blower spray amount, which is used to inject water at high pressure into the furnace of the fluidized bed boiler 1A, to this water injection amount Ww. The input amount estimation device 1B also has an input unit 31 to which data from the data acquisition unit 1C is input, a control unit 33 that controls the operation of the fluidized bed boiler 1A, such as the input amount of biomass fuel D, and a storage unit 34 that stores various data. The input unit 31 is a communication interface that can receive data from the data acquisition unit 1C. The fluidized bed boiler control method involves having a computer perform two steps: an estimation step of estimating the amount of biomass fuel D to be input using an input amount estimation device 1B, and a control step of controlling the operation of the fluidized bed boiler 1A based on the input amount estimated in the estimation step.

[0035] The data output unit 1D is capable of communicating with the input amount estimation device 1B and includes a display unit 35, which is a display capable of showing the estimation results of the estimation unit 32, and an operation control device 36 that centrally controls the operation of the power generation system 1. The input amount estimation device 1B may be built into the operation control device 36, or it may be a separate computer from the operation control device 36. The display unit 35 may be a portable tablet terminal or the like, or it may be the display of the input amount estimation device 1B or the operation control device 36.

[0036] The storage unit 34 is hardware composed of an HDD or the like, and stores various data over a predetermined period of time. The storage unit 34 stores at least the amount of forced air Vp (kNm 3 / h), forced air temperature Tp (°C), secondary air volume Vs (kNm 3 / h), secondary air temperature Ts (°C), exhaust gas volume Ve (kNm 3 ( / h), exhaust gas oxygen concentration Oe (%), steam volume Vw (kNm3 / h), feed water temperature Tw (°C), water injection rate Ww (t / h), power generation efficiency, generated electric power (kW), the lower calorific value (kcal / kg) and input rate (t / h) of biomass fuel D described later are stored in time series. Note that the storage unit 34 may be the hardware of the input rate estimation device 1B or the operation control device 36, or may be a cloud server.

[0037] Hereinafter, an example of estimating the input rate of biomass fuel D (hereinafter referred to as input rate W (t / h)) by the estimation unit 32 will be described.

[0038] The exhaust gas volume Ve (kNm 3 / h) can be obtained by the following formula (1) in which the theoretical exhaust gas volume generated when biomass fuel D is completely burned is added with the excess air volume Va (kNm 3 / h) and the water injection rate Ww. The exhaust gas volume Ve measured by the exhaust gas measurement unit 21 uses the one-hour average value, and a correction coefficient may be multiplied based on the operation record. Here, the coefficient α = 22.4 / 18, which is a coefficient for converting the water injection rate Ww into the water vapor volume. The exhaust gas volume Ve (kNm 3 / h) = input rate W (t / h) × theoretical exhaust gas volume (kNm 3 / h / t) + excess air volume Va (kNm 3 / h) + water injection rate Ww (t / h) × coefficient α ··· Formula (1)

[0039] Here, when the excess air volume Va (kNm 3 / h) is the air ratio Ra (21 / (21 - Oe)) obtained from the exhaust gas oxygen concentration Oe, it can be obtained by the following formula (2). The exhaust gas oxygen concentration Oe measured by the exhaust gas measurement unit 21 uses the one-hour average value. The pushed-in air volume Vp measured by the air measurement unit 20 uses the one-hour average value, and the secondary air volume Vs measured by the air measurement unit 20 uses the one-hour average value for every 5 locations with different heights along the vertical direction. To the total value V, the one-hour average value of the burner combustion air volume may be added as necessary, and a correction coefficient may be multiplied based on the operation record, or the leak air volume and purge air volume entering the furnace from the device gap may be added. The excess air volume Va (kNm 3 / h) = Forced air volume Vp(kNm 3 / h) and secondary air volume Vs(kNm 3 The sum of / h) V × (Ra-1) / Ra... Equation (2)

[0040] Furthermore, the input amount W (t / h) of biomass fuel D has the following relationship according to the definition of power generation efficiency: equation (3) below. The generated power (kW) is the hourly average value obtained by measuring the power output from the steam turbine generator 4. Input W (t / h) = Generated power (kW) / {0.86 × Power generation efficiency × Lower heating value (kcal / kg)} ...Equation (3)

[0041] Power generation efficiency is the ratio of generated power (kW) to the heat energy (kW) of biomass fuel D, calculated from the heat balance of fluidized bed boiler 1A. The heat energy (kW) of biomass fuel D can be calculated by subtracting the heat energy input to fluidized bed boiler 1A (excluding the heat energy of biomass fuel D) from the heat energy output from fluidized bed boiler 1A.

[0042] The amount of heat output from the fluidized bed boiler 1A mainly consists of heat generated from the amount of exhaust gas discharged by the fluidized bed furnace 2 and heat generated from the amount of steam supplied from the boiler 3 to the steam turbine generator 4. The heat generated from the amount of exhaust gas can be calculated by subtracting the amount of leaked air generated downstream of the boiler 3 from the amount of exhaust gas Ve, and then multiplying the result by the temperature and specific heat. The heat generated from the amount of steam supplied from the boiler 3 to the steam turbine generator 4 can be calculated by multiplying the amount of steam Vw by the steam enthalpy. In addition, the heat carried out by the sand layer 10 and the heat radiated by the blower and boiler may also be added to the amount of heat output from the fluidized bed boiler 1A.

[0043] The amount of heat input to the fluidized bed boiler 1A (excluding the heat of biomass fuel D) is mainly due to the heat input from the forced air supplied to the sand layer 10 via the blower 11, the heat input from the secondary air supplied to the upper region of the fluidized bed furnace 2, and the heat input from the water supplied to the boiler 3 from the feedwater device 8. The heat input due to the forced air supplied to the sand layer 10 via the blower 11 can be calculated by multiplying the amount of forced air Vp, the forced air temperature Tp, and the specific heat. The heat input due to the secondary air supplied to the upper region of the fluidized bed furnace 2 can be calculated by multiplying the amount of secondary air Vs, the secondary air temperature Ts, and the specific heat. The heat input due to the water supplied to the boiler 3 from the feedwater device 8 can be calculated by multiplying a predetermined feedwater amount, the feedwater temperature Tw, and the feedwater enthalpy.

[0044] Thus, the power generation efficiency is the ratio of generated electricity to the heat quantity of biomass fuel D, calculated based on values ​​input to the input unit 31, such as the amount of forced air Vp and forced air temperature Tp flowing into the fluidized bed boiler 1A, the amount of secondary air Vs and secondary air temperature Ts, the temperature of the feedwater supplied to the fluidized bed boiler 1A (feedwater temperature Tw), the amount of exhaust gas Ve, and the amount of steam Vw.

[0045] In this embodiment, under predetermined conditions where the composition, lower heating value, and ash content of the biomass fuel D in a dry state are kept constant, the relationship between the lower heating value and the theoretical exhaust gas volume is approximated by a linear function, as shown in Figure 3, and the relationship shown in the following approximation equation (4) is set (A=0.000826, B=1.74). Theoretical exhaust gas amount (kNm 3 / h / t)=A×lower calorific value (kcal / kg)+B...Equation (4)

[0046] By rearranging equations (1) to (4) above, the lower heating value (kcal / kg) of biomass fuel D can be calculated as shown in equation (5) below. Lower heating value (kcal / kg) = B ÷ [{Ve - V × (Ra - 1) / Ra - Ww × coefficient α} × power generation (kW) / (0.86 × power generation efficiency) - A] ... Equation (5)

[0047] By substituting the lower heating value (kcal / kg) obtained in this way into equation (3), the input amount W (t / h) of biomass fuel D can be estimated. Figure 4 shows the control flow of the input amount estimation device 1B according to this embodiment.

[0048] First, the input unit 31 acquires measurement data such as the amount of forced air Vp (kNm3 / h), forced air temperature Tp (°C), secondary air amount Vs (kNm3 / h), secondary air temperature Ts (°C), exhaust gas amount Ve (kNm3 / h), exhaust gas oxygen concentration Oe (%), steam amount Vw (kNm3 / h), feedwater temperature Tw (°C), and water injection amount Ww (t / h) obtained from the data acquisition unit 1C (#41). For items of this measurement data where the change in input value is extremely small, it may be possible to standardize them instead of acquiring them each time. Next, the estimation unit 32 calculates the hourly average value of the power generated (kW) in the steam turbine generator 4 and calculates the power generation efficiency based on the amount of forced air Vp and forced air temperature Tp, secondary air amount Vs and secondary air temperature Ts, feedwater temperature Tw, exhaust gas amount Ve, and steam amount Vw (#42). Next, the estimation unit 32 calculates the lower heating value (kcal / kg) of the biomass fuel D based on the above-mentioned equation (5) (#43). Then, the estimation unit 32 estimates the input amount W (t / h) of the biomass fuel D by substituting this calculated lower heating value (kcal / kg) into equation (3) (#44). These input air amount Vp and input air temperature Tp, secondary air amount Vs and secondary air temperature Ts, feedwater temperature Tw, exhaust gas amount Ve and steam amount Vw, power generation efficiency, power generated (kW), lower heating value (kcal / kg), and input amount W (t / h) are stored in the storage unit 34.

[0049] Next, the control unit 33 controls the operation of the fluidized bed boiler 1A based on the estimated input amount W (t / h) of biomass fuel D (#45). For example, the control unit 33 changes the feed speed of the conveyor 6 to increase or decrease the input amount W of biomass fuel D in order to optimize power generation efficiency and prevent clinker formation. The control unit 33 also displays the operating status of the fluidized bed boiler 1A on the display unit 35 and manages the quality and quantity of biomass fuel D stored in the hopper 5. In this way, by estimating and displaying the input amount W of biomass fuel D, it is possible to change the amount of biomass fuel D that the wheel loader H replenishes in the hopper 5, or to change the quality of biomass fuel D according to the season. Furthermore, by knowing the input amount W, it is possible to adjust the fuel procurement plan and manage the fuel stock appropriately, and it can also be used as an indicator for adjusting the input amount frequency and fuel mixing ratio when the wheel loader H is operated automatically. If the input amount estimation device 1B continues to monitor operation (#46 No), it repeats the control flow from #41 to #45, and if it terminates the monitoring operation (#46 Yes), it stops the control. [Examples]

[0050] Figure 5 shows a conventional method in which the input rate W(t / h) of biomass fuel D (wood chips) was estimated from the rotation speed of the conveyor belt 6, and this embodiment in which the input rate W(t / h) of biomass fuel D (wood chips) was estimated using the input rate estimation device 1B of this embodiment. As shown in the figure, when the input rate W(t / h) measured using a weighing instrument is set to 1, this embodiment approximated the average value of 1 over a year more closely than the conventional example. Furthermore, in this embodiment, the estimation accuracy was improved, especially during the summer months when humidity is high and the moisture content of biomass fuel D tends to fluctuate. [Industrial applicability]

[0051] This invention can be applied to a power generation system that generates electricity using steam produced by heat exchange with exhaust gas discharged from a fluidized bed boiler. [Explanation of Symbols]

[0052] 1: Power generation system 1A: Fluidized bed boiler 1B: Input amount estimation device 2:Fluidized bed furnace 3: Boiler 4: Steam turbine generator (power generation device) 8: Water supply device 10: Sand layer 20: Air measurement unit 21: Exhaust gas measurement unit 22: Water supply measurement unit 23: Steam measurement unit 24: Cooling water measurement unit 31: Input section 32: Estimation part D: Biomass fuel (combustible material) Oe: Exhaust gas oxygen concentration Tp: Forced air temperature Ts: Secondary air temperature Tw: Water supply temperature Ve: Exhaust gas volume Vp: Forced air volume Vs: Secondary air volume Vw: Steam volume W: Input amount Ww: Water injection amount

Claims

1. In a power generation system that generates electricity using steam produced by heat exchange with exhaust gas discharged from a fluidized bed boiler, an input amount estimation device for estimating the amount of combustible material to be input to the fluidized bed boiler, An input unit into which the amount and oxygen concentration of the exhaust gas, the amount and temperature of the air flowing into the fluidized bed boiler, the temperature of the feedwater supplied to the fluidized bed boiler, and the amount of steam are input, The system includes an estimation unit that estimates the amount of combustible material to be added based on the input value of the input unit, The estimation unit, The calculation of power generation efficiency based on the power output value from the steam turbine generator, the amount of air and air temperature flowing into the fluidized bed boiler, the temperature of the feedwater supplied to the fluidized bed boiler, the amount of exhaust gas, and the amount of steam, Calculation of the lower heating value of the combustible material based on the calculated power generation efficiency, power generated, amount of exhaust gas and oxygen concentration, amount of air flowing into the fluidized bed boiler and amount of steam, An input amount estimation device that estimates the input amount of combustible material based on the calculated lower heating value, the power generation efficiency, and the generated power.

2. The input amount estimation device according to claim 1, wherein the estimation unit estimates the input amount of combustible material using an approximation formula between the lower heating value and the theoretical value of the exhaust gas amount.

3. The input amount estimation device according to claim 1 or 2, wherein the input unit is further configured to input the amount of water injected into the fluidized bed boiler.

4. The input amount estimation device according to claim 1 or 2, wherein the combustible material includes wood chips.

5. The input amount estimation device according to claim 4, wherein the combustible material is biomass fuel including the wood chips.

6. A power generation system comprising: an input amount estimation device according to claim 1 or 2; a fluidized bed boiler; and a power generation device that generates electricity using the steam produced by heat exchange with the exhaust gas discharged from the fluidized bed boiler.

7. An estimation step of estimating the amount of combustible material to be added using the input amount estimation device according to claim 1 or 2, A fluidized bed boiler control method that causes a computer to perform a control step of controlling the operation of the fluidized bed boiler based on the amount of input estimated in the estimation step.

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