JP7193231B2 - Combustion control device and method for stoker furnace, and fuel transfer amount detection device and method - Google Patents

Description

The present invention relates to combustion control of a stoker furnace equipped with a stoker-type transfer mechanism.

2. Description of the Related Art Conventionally, a combustion plant is known that includes a combustion furnace (hereinafter referred to as "stoker furnace") having a stoker-type transfer mechanism. An example of such a combustion plant is a waste incineration plant equipped with a stoker furnace for incinerating waste, a waste feeding hopper for feeding waste into the stoker furnace, and an exhaust heat recovery boiler provided in the flue of the stoker furnace. be. A stoker furnace is equipped with a plurality of stoker stages provided along the direction of movement of fuel such as refuse on the bottom of the furnace. The fuel charged into the stoker furnace from the fuel charging hopper is sent onto the stoker by the fuel supply device, dried while moving on the stoker, and thermally decomposed by primary combustion. Pyrolysis gas produced by pyrolysis of the fuel undergoes secondary combustion in the flue, and the thermal energy of the flue gas is recovered by the heat recovery boiler. In the heat recovery boiler, the thermal energy of the flue gas is used to generate steam. The generated steam is used for power generation in power generation equipment.

In the combustion plant as described above, automatic combustion control of the stoker furnace is performed so that the amount of steam generated by the heat recovery boiler reaches the target amount of steam in order to ensure stable power generation in the power generation equipment. This automatic combustion control mainly adjusts the fuel transfer amount of the stoker, the combustion air supply amount, etc., based on the amount of steam generated by the heat recovery boiler.

In a stoker furnace, the fuel is generally moved by rocking the stoker, so the amount of fuel moved by the stoker is adjusted by changing the stoker operating speed. However, when the properties of the fuel change, an event occurs in which the fuel movement amount of the stoker is not necessarily proportional to the stoker operating speed. Therefore, stable automatic combustion control of the stoker furnace is difficult.

In response to such a problem, in Patent Document 1, in a waste incinerator, the fact that the coefficient of friction of the conveying surface of the stoker changes depending on the type of waste (in particular, the specific gravity and water content of the waste) has been found to improve the operating speed of the stoker and the movement of waste. Based on the detection value of the waste flow rate detector installed at the bottom of the waste feeding hopper and the weight of the waste picked up by the waste supply crane, the specific gravity of the waste was calculated. By changing the tilt angle of the stoker and the form of the transport surface based on the calculated value of the specific gravity of the dust, the coefficient of friction of the transport surface is adjusted, and a proportional relationship is established between the stoker operating speed and the amount of dust movement. I am trying to

Japanese Patent Publication No. 2-22294

It is considered that the fuel transfer amount of the stoker is affected not only by the coefficient of friction of the stoker's conveying surface, but also by other factors such as the state of accumulated fuel. Therefore, it is difficult to accurately estimate the amount of fuel movement based on the stoker operating speed and the inclination of the conveying surface.

The present invention has been made in view of the above circumstances, and its object is to improve the accuracy of estimating the amount of fuel transferred by the transfer mechanism in a stoker furnace equipped with a stoker-type transfer mechanism, thereby achieving stable automatic combustion control. is to realize

A method for detecting the amount of fuel movement according to one aspect of the present invention includes a drying zone for drying fuel made of waste , a combustion zone for burning treatment, and a post-combustion zone for ashing treatment in this order from upstream to downstream. In a stoker furnace equipped with a stoker-type transport mechanism for transporting fuel, a method for detecting the amount of movement of the fuel by the transport mechanism, comprising:
imaging the surface of the fuel layer with a thermal imaging camera at a plurality of imaging timings in a predetermined region upstream of the fuel ignition region in the dry zone;
a step of extracting, by image processing, at least one singular point that appears in common in a plurality of thermal images obtained by imaging;
and determining the amount of movement of the fuel based on the amount of displacement of the specific location over the plurality of thermal images and the time difference between the imaging timings of the plurality of thermal images.

A fuel movement amount detection device according to an aspect of the present invention includes a drying zone for drying fuel made of waste , a combustion zone for burning treatment, and a post-combustion zone for ashing treatment from upstream to downstream in this order. In a stoker furnace equipped with a stoker-type transport mechanism for transporting fuel, a device for detecting the amount of movement of the fuel by the transport mechanism,
a thermal imaging camera that captures images of the surface of the fuel layer in a predetermined region upstream of the fuel ignition region in the dry zone at a plurality of imaging timings ;
an image processing unit that extracts at least one singular point that appears in common in a plurality of thermal images obtained by the thermal imaging camera;
a fuel movement amount calculation unit that calculates the movement amount of the fuel based on the amount of displacement of the specific location over the plurality of thermal images and the time difference between the imaging timings of the plurality of thermal images. .

According to the fuel movement amount detection device and method described above, the estimation accuracy of the fuel movement amount by the transport mechanism is improved as compared with the case where the fuel movement amount is calculated based on the stoker operating speed.

A combustion control method for a stoker furnace according to an aspect of the present invention includes a drying zone for drying fuel made of waste , a combustion zone for burning treatment, and a post-combustion zone for ashing treatment, in this order from upstream to downstream. A combustion control method for a stoker furnace having a stoker-type transport mechanism for transporting fuel,
The surface of the fuel layer is imaged with a thermal imaging camera in a predetermined first region upstream of the ignition region of the fuel in the dry zone, and the fuel surface temperature, which is the radiation temperature of the fuel before ignition, is obtained from the obtained thermal image. and estimating the fuel calorific value from the fuel surface temperature;
In a predetermined second region upstream of the ignition region in the dry zone, the surface of the fuel layer is imaged with a thermal imaging camera at a plurality of imaging timings, and at least one image that is commonly captured in a plurality of obtained thermal images a step of extracting a unique portion and obtaining a fuel movement amount based on a displacement amount of the unique portion over the plurality of thermal images and a time difference between imaging timings of the plurality of thermal images;
measuring the fuel surface level of the dry zone and determining the fuel layer thickness of the dry zone from the obtained fuel surface level;
The amount of heat input into the furnace or an amount correlated with it is detected, and the fuel calorific value, the amount of fuel movement, and the fuel layer thickness are adjusted so that the detected heat input becomes a given heat input set value. and adjusting at least one of the input amount of the fuel, the operating speed of the stoker, and the supply amount of air for combustion of the fuel based on the above.

A combustion control device for a stoker furnace according to an aspect of the present invention conveys the fuel from upstream to downstream in the order of a drying zone for drying the fuel, a combustion zone for combustion, and a post-combustion zone for ashing. A stoker furnace combustion control device comprising a stoker-type transfer mechanism,
a first thermal imaging camera that captures an image of the surface of the fuel layer in a predetermined first region upstream of the fuel ignition region in the dry zone;
a first image processing unit that obtains a fuel surface temperature, which is a radiation temperature of the fuel, from a thermal image obtained by the first thermal image camera;
a fuel calorific value calculation unit that calculates a fuel calorific value based on the fuel surface temperature;
a second thermal imaging camera that captures images of the surface of the fuel layer in a predetermined second region upstream of the ignition region in the dry zone at a plurality of imaging timings ;
a second image processing unit for extracting at least one singular point commonly appearing in a plurality of thermal images obtained by the second thermal imaging camera;
a fuel movement amount calculation unit that calculates a fuel movement amount based on the amount of displacement of the specific location over the plurality of thermal images and the time difference between the imaging timings of the plurality of thermal images;
a level meter for measuring the fuel surface level in the dry zone;
a fuel movement amount calculation unit that calculates the fuel layer thickness of the dry zone from the fuel surface level obtained by the level meter;
a heat input detector that detects the amount of heat input into the furnace or an amount correlated therewith;
Based on the fuel calorific value, the fuel movement amount, and the fuel layer thickness so that the heat input detected by the heat input detector becomes a given heat input set value, the fuel input amount, and a combustion control unit that adjusts at least one of a stoker operating speed and a supply amount of air for combustion of the fuel.

According to the stoker furnace combustion control apparatus and method, the accuracy of estimating the amount of fuel movement is improved as compared with the case where the amount of fuel movement is calculated based on the stoker operating speed. By performing combustion control of the stoker furnace using such a fuel movement amount, stable automatic combustion control can be realized.

According to the present invention, in a stoker furnace equipped with a stoker-type transfer mechanism, the accuracy of estimating the amount of dust moved by the transfer mechanism is improved, so it is possible to contribute to the realization of stable automatic combustion control.

FIG. 1 is a schematic diagram showing the overall configuration of a combustion plant including a stoker furnace according to one embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the control system of the combustion plant. FIG. 3 is a block diagram of automatic combustion control performed by the combustion control device. FIG. 4 is a block diagram of automatic combustion control performed by the combustion control device. FIG. 5 is a block diagram of automatic combustion control performed by the combustion control device.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of a combustion plant 100 including a stoker furnace 1 according to one embodiment of the present invention. Here, as an example of the combustion plant 100 including the stoker furnace 1, a waste incineration plant will be described. A waste incineration plant burns waste as fuel, recovers the thermal energy of the combustion exhaust gas in an exhaust heat boiler, and generates power using the recovered thermal energy.

A combustion plant 100 shown in FIG. 1 includes a fuel storage facility 3 that stores waste as fuel, a stoker furnace 1 , and a boiler 2 that recovers exhaust heat from the stoker furnace 1 . Furthermore, the combustion plant 100 includes a steam turbine 34 and a generator 35 that generate power using exhaust heat from the stoker furnace 1 recovered by the boiler 2 . The combustion plant 100 according to this embodiment includes a fuel storage facility 3 and power generation facilities (steam turbine 34, generator 35), which may be independent of the combustion plant 100.

[Fuel storage facility 3]
The fuel storage facility 3 has a pit 60 which is adjacent to the stoker furnace 1 and temporarily stores fuel to be processed in the stoker furnace 1 . A crane 6 is provided above the pit 60 for charging the fuel in the pit 60 into the stoker furnace 1 . The crane 6 includes a bucket 61 , and can be moved to any position on the pit 60 by operating the crane 6 with a crane driving device 62 . The crane 6 grabs the fuel in the pit 60 with a bucket 61 and feeds the fuel into a feeding hopper 12 (described later) of the stoker furnace 1 . Although a conveyor is interposed between the crane 6 and the charging hopper 12 in FIG. 1, the conveyor may be omitted.

[Stoker Furnace 1]
The stoker furnace 1 is a combustion furnace provided with a stoker-type transfer mechanism 15 . The stoker furnace 1 is provided with a main combustion chamber 14 (primary combustion chamber) and a secondary combustion chamber 19 . In the main combustion chamber 14, a drying zone 55 for drying the fuel, a combustion zone 56 for burning the fuel, and a post-combustion zone 57 for ashing the fuel are arranged in this order from upstream to downstream. A transport mechanism 15 of the type is provided.

The conveying mechanism 15 comprises a drying stoker 15a forming a drying zone 55, a combustion stoker 15b forming a combustion zone 56, and a post-combustion stoker 15c forming a post-combustion zone 57. include. A discharge chute 18 for discharging incinerated ash from the main combustion chamber 14 is provided downstream of the post-combustion stoker 15c. Above the drying stoker 15a and on the ceiling of the main combustion chamber 14, an imaging device 71 for imaging the fuel in the drying zone 55 and a level meter 72 for measuring the surface level of the fuel in the drying zone 55 are provided. .

The stokers 15a, 15b, 15c are reciprocatingly driven by a stoker driving device 42 so as to send fuel downstream. The stoker drive device 42 includes drive cylinders 42a, 42b, 42c provided corresponding to the respective stoker 15a, 15b, 15c. The stoker 15a, 15b, 15c is oscillatingly driven by these drive cylinders 42a, 42b, 42c interlockingly or independently.

A wind box into which primary combustion air 51 is introduced is provided below each of the stokers 15a, 15b, and 15c. supplied. The amount of primary combustion air 51 supplied is regulated by a flow control device 43 . The flow control device 43 includes a blower 43d that sends the primary combustion air 51 to each wind box, and dampers 43a, 43b, 43c that adjust the amount of supply of the primary combustion air 51 to each wind box. Secondary combustion air 52 is also supplied from the ceiling of the main combustion chamber 14 into the main combustion chamber 14 . The amount of secondary combustion air 52 supplied is regulated by a flow controller 44 .

An input hopper 12 is connected to the inlet of the main combustion chamber 14 via a chute 13 . A feeder 41 is provided at the entrance of the main combustion chamber 14 to push the fuel onto the drying stoker 15a. The feeder 41 adjusts the amount of fuel injected into the main combustion chamber 14 .

In the stoker furnace 1 configured as described above, the fuel charged from the charging hopper 12 through the chute 13 to the inlet of the main combustion chamber 14 is pushed out by the feeder 41 onto the drying stoker 15a. While passing through the drying zone 55, the fuel is dried by the primary combustion air 51 and the radiant heat of the main combustion chamber 14 and ignited. A portion of the ignited fuel is pyrolyzed while passing through the combustion zone 56 to generate combustible pyrolysis gases. This pyrolysis gas rides on the primary combustion air 51 and moves to the upper part of the main combustion chamber 14 and is flame-burned together with the secondary combustion air 52 . The temperature of the fuel further rises due to heat radiation associated with this flame combustion. In addition, the rest of the ignited fuel is burned while passing through the combustion zone 56 and the post-combustion zone 57, and the incineration ash remaining after combustion is discharged from the discharge chute 18 and sent to an ash treatment facility (not shown). The flue gas of the main combustion chamber 14 is mixed with the secondary combustion air 52 blown from the ceiling portion on the downstream side of the main combustion chamber 14 and completely combusted in the secondary combustion chamber 19 .

[Boiler 2]
The outlet of the secondary combustion chamber 19 of the stoker furnace 1 is connected to the boiler 2 , and flue gas from the stoker furnace 1 flows into the boiler 2 . A temperature sensor 38 for detecting the temperature of flue gas from the stoker furnace 1 is provided near the exit of the secondary combustion chamber 19 or the entrance of the radiation chamber 20 . The boiler 2 is provided with a series of flue gas flow paths including a radiant chamber 20 (first flue), a second flue 21 and a third flue 22 .

Water pipes 23 are stretched around the walls of the radiant chamber 20 and the second flue 21 . The heat-recovery water flowing through the water tube 23 recovers the heat in the radiant chamber 20 and the second flue 21, and is partially vaporized into steam and returned to the boiler drum 24. The steam in boiler drum 24 is sent to superheater 25 . The amount of steam sent from the boiler drum 24 to the superheater 25 (main steam amount) is measured by a steam flow meter 39 provided downstream of the superheater 25 in the flow of steam. The superheater 25 has a superheating tube 27 installed in the third flue 22 . The steam sent from the boiler drum 24 is further superheated to high temperature and high pressure while passing through the superheating tube 27 and sent to the steam turbine 34 that drives the generator 35 .

The flue gas that has passed through the boiler 2 is discharged from an exhaust port 29 provided in the third flue 22 to an exhaust path 28 . The exhaust path 28 is provided with a bag filter 31, an induced draft fan 32, and the like, and the exhaust gas from the boiler 2 is discharged from the chimney 33 into the atmosphere after the dust is separated by the bag filter 31.

The operation of the combustion plant 100 configured as described above is controlled by the combustion control device 10 . FIG. 2 is a diagram showing the configuration of the control system of the combustion plant 100. As shown in FIG. As shown in FIG. 2, the combustion control device 10 includes a communication device 64, a processing device 65, an input device 66, a display device 67, and various storage devices M1 to M3. Each of the memory devices M1 to M3 may be composed of separate memory devices, or a plurality of memory devices may be composed of one memory device.

The processing device 65 is a computer having an arithmetic unit such as a CPU and a storage unit such as a ROM and a RAM. to control. The processing device 65 may be configured by one computer, or may be configured by distributing functions among a plurality of computers.

The input device 66 is configured by a mouse and a keyboard, and is means for receiving input by user's operation. The input device 66 outputs information input by a user's operation to the processing device 65 .

The display device 67 is composed of a display device such as a liquid crystal display, and displays information corresponding to display data given from the processing device 65 on a screen.

The communication device 64 is controlled by the processing device 65 to transmit and receive data to and from the feeder 41, the stoker drive device 42, the flow control devices 43 and 44, the imaging device 71, etc. using wireless or wired communication means. , and also receives detection signals from various instruments such as the temperature sensor 38, the steam flow meter 39, the level meter 72, and the like.

The storage device M1 stores a main steam amount-heat input correspondence formula that associates the relationship between the target steam amount and the heat input amount. The storage device M2 stores a fuel surface temperature-fuel calorific value correspondence formula that associates the relationship between the fuel surface temperature and the calorific value of the fuel. In addition to the data stored in the storage devices M1 and M2, the storage device M3 stores data necessary for executing automatic combustion control.

[Combustion Control Method for Stoker Furnace 1]
The combustion control device 10 performs automatic combustion control of the stoker furnace 1 so as to keep the steam pressure generated by the boiler 2 constant. The combustion control device 10 executes a predetermined program stored in the storage device M3 or memory in advance by the processing device 65, so that the first image processing section 651, the second image processing section 652, the fuel calorific value calculation section 653, It functions as a fuel movement amount calculation unit 654, a fuel layer thickness calculation unit 655, a combustion control unit 656, and the like.

The first image processing unit 651 obtains a thermal image from the imaging device 71 and detects the surface temperature distribution of the fuel from this thermal image.

The imaging device 71 includes one or more thermal imaging cameras mounted on the ceiling of the main combustion chamber 14 facing the dry stoker 15a. The one or more thermal imaging cameras include a filtered thermal imaging camera 71a that cancels flames with a bandpass filter and detects infrared radiation emitted from the fuel surface, and a filterless thermal imaging camera 71b that does not have a bandpass filter attached. including. However, the filter-equipped thermal imaging camera 71a with the band-pass filter removed may be used as the unfiltered thermal imaging camera 71b. It is desirable that the imaging regions of the filtered thermal imaging camera 71a and the unfiltered thermal imaging camera 71b are substantially the same.

The filter-equipped thermal image camera 71a is infrared detection means for detecting infrared energy, and detects infrared energy absorption bands by CO, CO ₂ , NOX, SOX, and H ₂ O in the flame generated from the fuel in the drying zone 55. A bandpass filter with a transmission wavelength of about 3.9 (3.6-4) μm is attached to avoid detection of radiant energy from the gas body. As a result, the captured image obtained by the thermal image camera 71a with filter, that is, the thermal image obtained through the band-pass filter is obtained by detecting the radiant energy through the flame generated from the fuel in the drying zone 55. FIG.

In the imaging device 71, the surface of the fuel in the dry zone 55 is imaged by the filtered thermal imaging camera 71a and the non-filtered thermal imaging camera 71b at predetermined time intervals. The first image processing unit 651 obtains a thermal image through the filter and a thermal image without the filter, compares these thermal images, and determines the area where a predetermined temperature difference is detected as the ignition of the drying zone 55 . Judge as an area. Alternatively, the first image processing unit 651 uses a filtered thermal image captured by the thermal imaging camera 71a with a filter, and the temperature difference from the reference temperature in this thermal image is a predetermined value that can be determined as "ignition". may be determined as the ignition region. Furthermore, the first image processing unit 651 determines an area of a predetermined width immediately upstream of the ignition area as an ignition start area, and obtains the average value of the fuel surface temperature in the ignition start area.

The second image processing unit 652 obtains thermal images from the imaging device 71 through a filter, and detects the moving speed of the fuel from a plurality of thermal images captured at different imaging timings. In this embodiment, the first image processing unit 651 and the second image processing unit 652 use the same thermal image and share the imaging device 71. may be provided. Also, the imaging regions of the thermal image used by the first image processing unit 651 and the thermal image used by the second image processing unit 652 may be different.

The second image processing unit 652 detects a location where the temperature of the fuel is significantly different from that of the surroundings, or the size of the fuel is significantly larger than that of the surroundings, from the filtered thermal image captured at the previous timing. Alternatively, a small point is set as a singular point, and its feature point is extracted. In addition, the second image processing unit 652 searches for at least one peculiar point common to a plurality of thermal images based on the feature points extracted earlier from the filtered thermal image captured at a later timing. Furthermore, the second image processing unit 652 calculates the amount of movement of the common specific portion of the thermal image captured at the earlier timing and the thermal image captured at the later timing. Note that since the size and temperature of the fuel in the dry zone 55 do not change abruptly, it is possible to extract common peculiar points in a plurality of thermal images captured at different imaging timings. Also, the plurality of thermal images used by the second image processing unit 652 may be three or more.

The fuel calorific value calculation unit 653 uses, for example, a fuel surface temperature-fuel calorific value correspondence formula stored in advance in the storage device M2 from the average value of the fuel surface temperature in the ignition start region obtained by the first image processing unit 651. to calculate the fuel calorific value. The determined fuel calorific value is used for combustion control as a "calorific value measurement value 82 (see FIG. 3)."

The fuel movement amount calculation unit 654 calculates the amount of movement of the common specific portion of the thermal image obtained by the second image processing unit 652 and the thermal image obtained by the subsequent imaging timing, and the timing of the imaging. The amount of fuel movement is calculated from the time difference. The determined fuel movement amount is used for combustion control as a "fuel movement amount measurement value 92 (see FIG. 4)".

The second image processing unit 652 and the fuel movement amount calculation unit 654 described above, and the imaging device 71 may constitute a fuel movement amount detection device that detects the movement amount of fuel by the transport mechanism 15 .

Based on the surface level of the fuel detected by the level meter 72, the fuel layer thickness calculator 655 obtains the distance from the level of the transfer surface (upper surface) of the dry stoker 15a to the surface level of the fuel, that is, the layer thickness of the fuel. be able to. The determined fuel layer thickness is used for combustion control as a "fuel layer thickness measurement value 83 (see FIG. 3)".

The level gauge 72 is a non-contact type level gauge using microwaves and detects the surface level of the fuel in the dry zone 55 . As the level meter 72, a pulse radar type microwave level meter may be used. A pulse radar type microwave level meter emits a pulse radar wave from a horn antenna, measures the round-trip propagation time until the echo hits the object to be measured and returns to the microwave level meter, and then calculates the distance. .

The level meter 72 according to this embodiment is a microwave level meter, but other known level detection means may be used instead. For example, a stereo camera is provided to photograph the fuel layer simultaneously from a plurality of different directions, and based on the surface level of the fuel obtained from the images captured by the stereo camera, the distance from the transport surface level of the dry stoker 15a to the surface level of the fuel, That is, the layer thickness of the fuel may be obtained.

The combustion control unit 656 uses the detected heat input index into the furnace, the measured calorific value 82, the measured fuel layer thickness 83, and the measured fuel transfer amount 92 to provide the detected heat input index. Automatic combustion control of the stoker furnace 1 is performed so that the heat input index target value of . The automatic combustion control adjusts the amount of fuel input by the feeder 41, the amount of fuel movement by the transfer mechanism 15, and the flow rates of the primary combustion air 51 and the secondary combustion air 52 required for burning the fuel.

In this embodiment, the main steam flow rate of the boiler 2 is used as the heat input index into the furnace. In this embodiment, the steam flow meter 39 is used as the heat input index detector, and the main steam flow rate detected by the steam flow meter 39 is the heat input index detection value. The combustion control unit 656 sets the "heat input setting value 81 (see FIG. 3)" based on the heat input index target value. The heat input index target value according to the present embodiment is the target steam amount. can be asked for.

3 to 5 are block diagrams of automatic combustion control performed by the combustion control section 656 of the combustion control device 10. FIG. As shown in FIG. 3, the combustion control unit 656 acquires and uses a heat input set value 81, a calorific value measured value 82, a fuel layer thickness measured value 83, and a fuel movement amount measured value 92. In the combustion control unit 656, the multiplier 84 calculates the heat input measurement value 85 by multiplying the calorific value measurement value 82 and the fuel layer thickness measurement value 83, and the subtractor 86 calculates the heat input set value 81 and the heat input measurement value. 85 is calculated and this deviation is input to the PID controller 87 . The PID controller 87 outputs a fuel input amount set value 88, a combustion air amount set value 89, and a fuel movement amount set value 90 based on the acquired deviation.

The combustion control device 10 controls the primary combustion air flow rate control device 43 so that the primary combustion air and the secondary combustion air corresponding to the combustion air amount set value 89 are supplied into the furnace based on the combustion air amount set value 89. and the operation of the secondary combustion air flow controller 44 . The combustion air amount set value 89 may include a primary combustion air set value and a secondary combustion air set value.

Further, as shown in FIG. 4, in the combustion control unit 656 of the combustion control device 10, the subtractor 91 calculates the deviation between the fuel movement amount set value 90 and the fuel movement amount measurement value 92, and this deviation is used by the PID controller. 93. A stoker operating speed 94 is output from the PID controller 93 based on the acquired deviation. The stoker driving device 42 operates the stoker 15a, 15b, 15c by reflecting the output stoker operating speed 94 on the target value. In the stoker-type transport mechanism 15, the stoker 15a, 15b, 15c swings at predetermined time intervals to push out the fuel, thereby transporting the fuel. Therefore, the above-mentioned "stalker operating speed" is determined by the swinging speed of the stoker and the interval between swinging and stopping of the stoker. The stoker driving device 42 adjusts at least one of the swing speed of the stoker and the interval between the swing and stop of the stoker to bring the operating speed of the stoker 15a, 15b, 15c closer to the target value. The operating speeds of the stokers 15a, 15b, and 15c in each stage may be the same, or may be independent of each other.

Similarly, as shown in FIG. 5, in the combustion control unit 656 of the combustion control device 10, the subtractor 95 calculates the deviation between the fuel input amount set value 88 and the fuel input amount measured value 96, and this deviation is used for PID control. input to device 97 . The fuel input amount measurement value 96 may be obtained, for example, by calculation based on the input weight by the crane 6 and the input interval. It may be obtained from the weight change of A feeder operation amount 98 is output from the PID controller 97 based on the acquired deviation. The feeder manipulated variables 98 may be adjusted by feeding back the dry stage fuel layer thickness measurements 83 and fuel displacement measurements 92 . The feeder 41 operates the feeder 41 by reflecting the output feeder operation amount 98 on the target value. The feeder 41 brings the feeder operation amount closer to the target value by adjusting at least one of the operation speed and operation frequency of the feeder 41 .

As described above, the combustion control device 10 for the stoker furnace 1 of the present embodiment is
Thermal imaging cameras 71a and 71b (first thermal imaging cameras) for capturing an image of a predetermined region (first region) upstream of the fuel ignition region in the dry zone 55;
a first image processing unit 651 that obtains the fuel surface temperature, which is the radiation temperature of the fuel, from the thermal images obtained by the thermal image cameras 71a and 71b;
a fuel calorific value calculator 653 that obtains the fuel calorific value based on the fuel surface temperature;
A thermal imaging camera 71a (second thermal imaging camera) that captures an image of a predetermined region (second region) upstream of the ignition region of the dry zone 55;
a second image processing unit 652 for extracting at least one singular point commonly captured in a plurality of thermal images obtained by the thermal image camera 71a;
A fuel movement amount calculation unit 654 that obtains the fuel movement amount based on the amount of displacement of a specific location over a plurality of thermal images and the time difference between the imaging timings of the plurality of thermal images;
a level meter 72 for measuring the fuel surface level in the dry zone 55; a fuel layer thickness calculator 655 for obtaining the fuel layer thickness in the dry zone 55 from the fuel surface level obtained by the level meter 72;
a heat input index detector (in the present embodiment, a steam flow meter 39) that detects an amount that serves as an index of heat input into the furnace;
In order that the heat input index detected by the heat input index detector becomes a given heat input index set value, the amount of fuel input and the stoker operation are adjusted based on the fuel calorific value, the amount of fuel movement, and the thickness of the fuel layer. Combustion control 656 for adjusting at least one of velocity and air supply for combustion of fuel.

Further, the combustion control method for the stoker furnace of this embodiment includes:
A predetermined region (first region) upstream of the fuel ignition region in the dry zone 55 is imaged by the thermal imaging cameras 71a and 71b, and the fuel surface temperature, which is the radiation temperature of the fuel before ignition, is calculated from the obtained thermal image. and estimating the fuel calorific value from the fuel surface temperature;
A predetermined region (second region) on the upstream side of the ignition region of the dry zone 55 is imaged by the thermal imaging camera 71a, and at least one specific point that is commonly captured in the plurality of obtained thermal images is extracted, and a plurality of a step of determining the amount of fuel movement in the dry zone 55 based on the amount of displacement of the specific location over the thermal image and the time difference between the imaging timings of the plurality of thermal images;
measuring the fuel surface level of the dry zone 55 and determining the fuel layer thickness of the dry zone 55 from the obtained fuel surface level;
A heat input index into the furnace (in this embodiment, the main steam amount of the boiler 2) is detected, and the fuel calorific value and fuel transfer are adjusted so that the detected heat input index becomes a given heat input index set value. adjusting at least one of fuel input, stoker operating speed, and fuel combustion air supply based on volume and fuel layer thickness.

According to the combustion control device 10 and method for the stoker furnace 1 described above, the estimation accuracy of the fuel transfer amount is improved as compared with the case where the fuel transfer amount is calculated based on the stoker operating speed. By performing combustion control of the stoker furnace 1 using such a fuel movement amount, stable automatic combustion control can be realized.

Furthermore, as described above, the fuel movement amount detection device of the present embodiment includes the thermal image camera 71a for capturing an image of a predetermined region upstream of the fuel ignition region in the dry zone 55, and the thermal image camera 71a. Based on the image processing unit 652 that extracts at least one unique point that appears in common in the plurality of thermal images obtained, the displacement amount of the unique point across the plurality of thermal images, and the time difference between the imaging timings of the plurality of thermal images , and a fuel movement amount calculation unit 654 for obtaining the movement amount of fuel.

Further, the method of detecting the amount of fuel movement of the present embodiment includes the step of capturing an image of a predetermined region upstream of the fuel ignition region in the dry zone 55 with the thermal imaging camera 71a, and common to a plurality of thermal images obtained by the imaging. a step of extracting at least one peculiar point captured by image processing, and a step of determining the amount of movement of the fuel based on the amount of displacement of the peculiar point across the plurality of thermal images and the time difference between the imaging timings of the plurality of thermal images. and including.

According to the above-described device and method for detecting the amount of fuel movement in the stoker furnace 1, the estimation accuracy of the amount of fuel movement is improved as compared with the case where the fuel movement amount is calculated based on the stoker operating speed.

The stoker furnace 1 according to the present embodiment is of a parallel flow type, and the ceiling of the main combustion chamber 14 bends in the middle from the fuel input side, and then spreads above the combustion zone 56 and the post-combustion zone 57. , primary air and combustion gases flow from the drying zone 55 towards the post-combustion zone 57 . In such a furnace, the field of view of the thermal image camera 71a installed on the ceiling of the main combustion chamber 14 can be easily secured.

Although preferred embodiments of the present invention have been described above, the present invention may also include modifications of the details of the specific structures and/or functions of the above embodiments without departing from the spirit of the present invention. .

Reference Signs List 1: Stoker furnace 2: Boiler 3: Fuel storage facility 10: Combustion control device 12: Feeding hopper 14: Main combustion chamber 15: Transfer mechanisms 15a, 15b, 15c: Stoker 19: Secondary combustion chamber 39: Steam flow meter 41: Feeder 42 : Stoker drive devices 42a, 42b, 42c : Drive cylinder 43 : Primary combustion air flow controllers 43a, 43b, 43c : Damper 43d : Blower 44 : Secondary combustion air flow controller 55 : Dry zone 56 : Combustion zone 57 : Post-combustion zone 64 : Communication device 65 : Processing device 651, 652 : Image processing unit 653 : Fuel calorific value calculation unit 654 : Fuel transfer amount calculation unit 655 : Fuel layer thickness calculation unit 656 : Combustion control unit 66 : Input device 67 : Display device 71 : Imaging devices 71a, 71b : Thermal imaging camera 72 : Level gauge 100 : Combustion plant

Claims (4)

In a stoker furnace equipped with a stoker-type conveying mechanism for conveying the fuel from upstream to downstream in order of a drying zone for drying fuel, a combustion zone for burning treatment, and a post-burning zone for ashing treatment , a method for detecting the amount of movement of the fuel by the transport mechanism,
imaging the surface of the fuel layer with a thermal imaging camera at a plurality of imaging timings in a predetermined region upstream of the fuel ignition region in the dry zone;
a step of extracting, by image processing, at least one singular point that appears in common in a plurality of thermal images obtained by imaging;
determining the amount of movement of the fuel based on the amount of displacement of the specific location over the plurality of thermal images and the time difference between the imaging timings of the plurality of thermal images;
A method for detecting the amount of fuel movement. In a stoker furnace equipped with a stoker-type conveying mechanism for conveying the fuel from upstream to downstream in order of a drying zone for drying fuel, a combustion zone for burning treatment, and a post-burning zone for ashing treatment , a device for detecting the amount of movement of the fuel by the transport mechanism,
a thermal imaging camera that captures images of the surface of the fuel layer in a predetermined region upstream of the fuel ignition region in the dry zone at a plurality of imaging timings ;
an image processing unit that extracts at least one singular point that appears in common in a plurality of thermal images obtained by the thermal imaging camera;
a fuel movement amount calculation unit that calculates the movement amount of the fuel based on the amount of displacement of the specific location over the plurality of thermal images and the time difference between the imaging timings of the plurality of thermal images;
A device for detecting the amount of fuel movement. A stoker furnace equipped with a stoker-type conveying mechanism for conveying the fuel from upstream to downstream in order of a drying zone for drying fuel made of waste , a combustion zone for burning treatment, and a post-burning zone for ashing treatment. A combustion control method comprising:
The surface of the fuel layer is imaged with a thermal imaging camera in a predetermined first region upstream of the ignition region of the fuel in the dry zone, and the fuel surface temperature, which is the radiation temperature of the fuel before ignition, is obtained from the obtained thermal image. and estimating the fuel calorific value from the fuel surface temperature;
In a predetermined second region upstream of the ignition region in the dry zone, the surface of the fuel layer is imaged with a thermal imaging camera at a plurality of imaging timings, and at least one image that is commonly captured in a plurality of obtained thermal images a step of extracting a unique portion and obtaining a fuel movement amount based on a displacement amount of the unique portion over the plurality of thermal images and a time difference between imaging timings of the plurality of thermal images;
measuring the fuel surface level of the dry zone and determining the fuel layer thickness of the dry zone from the obtained fuel surface level;
A heat input index into the furnace is detected, and based on the fuel calorific value, the fuel transfer amount, and the fuel layer thickness, so that the detected heat input index becomes a given heat input index set value , adjusting at least one of the input amount of the fuel, the stoker operating speed, and the amount of air supplied for combustion of the fuel;
Combustion control method for stoker furnace. A stoker furnace equipped with a stoker-type conveying mechanism for conveying the fuel from upstream to downstream in order of a drying zone for drying fuel made of waste , a combustion zone for burning treatment, and a post-burning zone for ashing treatment. A combustion control device,
a first thermal imaging camera that captures an image of the surface of the fuel layer in a predetermined first region upstream of the fuel ignition region in the dry zone;
a first image processing unit that obtains a fuel surface temperature, which is a radiation temperature of the fuel, from a thermal image obtained by the first thermal image camera;
a fuel calorific value calculation unit that calculates a fuel calorific value based on the fuel surface temperature;
a second thermal imaging camera that captures images of the surface of the fuel layer in a predetermined second region upstream of the ignition region in the dry zone at a plurality of imaging timings ;
a second image processing unit for extracting at least one singular point commonly appearing in a plurality of thermal images obtained by the second thermal imaging camera;
a fuel movement amount calculation unit that calculates a fuel movement amount based on the amount of displacement of the specific location over the plurality of thermal images and the time difference between the imaging timings of the plurality of thermal images;
a level meter for measuring the fuel surface level in the dry zone;
a fuel layer thickness calculator that calculates the fuel layer thickness of the dry zone from the fuel surface level obtained by the level meter;
a heat input index detector that detects an amount that serves as an index for the amount of heat input into the furnace;
Based on the fuel calorific value, the fuel movement amount, and the fuel layer thickness, the amount of the fuel is adjusted so that the heat input index detected by the heat input index detector becomes a given heat input index set value. A combustion control unit that adjusts at least one of the input amount, the stoker operating speed, and the supply amount of the combustion air for the fuel,
Combustion control device for stoker furnace.

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