JP3619940B2 - Fluidized bed incinerator and its combustion method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an incinerator and an incineration method suitable for reducing harmful gases randomly generated in combustion of municipal waste or the like whose properties change significantly.
[0002]
[Prior art]
A conventional fluidized bed incinerator is a combustion type that uses only fluidized bed combustion, and high-calorie substances (vinyl, plastic products, paper waste, etc.) are mixed in an unbalanced manner like municipal waste. It is difficult to control harmful gases generated at random for incinerators whose properties change to such an extent that they cannot be predicted. For example, if garbage that burns at high temperatures, such as vinyl and plastic products, is introduced, Fluidized air that is excessive for combustion temporarily becomes high-temperature combustion, and a large amount of NOx is generated.
[0003]
Similarly, fluidized air that is too excessive as the amount of air at the early stage of combustion burns at a high rate at a high combustion speed, so that a large amount of CO is discharged outside the furnace at a high superficial velocity.
[0004]
[Problems to be solved by the invention]
The above prior art can only perform one form of combustion method called fluidized bed combustion, so in the combustion of incinerated products whose properties change significantly, a high-calorie, high-volatility synthetic resin that is randomly introduced In contrast to the incineration of fats and oils, the fluidized air that is too much as the air for burning them instantaneously burns at a fast combustion rate, and temporarily generates harmful gases such as high concentrations of NOx and CO.
[0005]
An object of the present invention is to suppress the generation of harmful gases due to fluctuations in the combustion state and the amount of incinerated materials to be charged.
[0006]
[Means for Solving the Problems]
The purpose of the above is to supply fluidized air to the fluidized bed and supply secondary air for combustion above the fluidized bed. The amount of state indicating the combustion state and the amount of incinerated material charged into the furnace In the combustion method of the fluidized bed incinerator for controlling the supply of fluidized air and secondary air for combustion based on the detection result and burning the incinerated product, the rate of increase in the amount of incinerated product input This is achieved by controlling the supply of fluidized air to stop the flow of the fluidized bed and switching from fluidized bed combustion to combustion when both of the increase amount and the increase amount are larger than preset values .
[0007]
The above purpose is also to set the combustion state and the incinerated state as the state quantity such as flame brightness, gas amount, gas concentration, furnace pressure, furnace temperature, amount of incinerated material input, drop speed, size, etc. Based on the output of the input amount detecting means, the state amount detecting means, and the outputs of these input amount detecting means and the state amount detecting means, if the waste input amount temporarily increases, the furnace is preceded or followed up. There is provided control means for switching the fluidized air into the multi-stage combustion air nozzle for combustion by a damper or the like, stopping the flow for several seconds to several minutes, and temporarily switching from fluidized bed combustion to combustion. Achieved by fluidized bed incinerator.
[0008]
By setting the supply amount of fluidized air to zero and supplying combustion air from the multistage combustion air nozzle, the combustion mode is switched from fluidized bed combustion having a relatively fast combustion speed to vertical combustion, that is, multistage combustion. By this switching, the synthetic resin with a large amount of volatile matter is burned at a slow burning rate, the temperature rise is suppressed, and the instantaneous generation of CO and NO x is reduced. In addition, paper dust or the like has a burning rate that is slower than that in the case of fluidized bed combustion, and an instantaneously high temperature can be avoided.
[0009]
【Example】
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a municipal waste incinerator to which the present invention is applied. The incinerator shown in the figure is connected to a fluidized bed incinerator body 18 for incinerating municipal waste, and this incinerator body 18 is connected via an input chute 17. baked却物the incinerator body 18 through the chute 17, i.e. a paper precipitator 16 for supplying the municipal waste, and air supply system for supplying fluidizing air and the multi-stage combustion air to the fluidized bed incinerator body 18, the And a control device that controls the air supply system.
[0010]
The fluidized bed incinerator main body 18 includes a plurality of fluidized air nozzles 24 for taking fluidized air into the lower portion thereof, and a plurality of multistage combustion air nozzles 14 for combustion that are placed above the fluidized bed portion.
[0011]
The air supply system includes a blower 19, a blower discharge duct 20 that is connected to the air discharge port of the blower 19 and has a downstream branching into two, and a switching damper 15 </ b> A connected to each of the two downstream ends of the blower discharge duct 20. 15B, the fluidized air supply duct 21 connecting the outlet side of the switching damper 15B and the fluidizing air nozzle 24 of the incinerator body 18 via the fluidizing air control damper 12, the outlet side of the switching damper 15A, and the incinerator body A multi-stage combustion air supply duct 22 for connecting 18 multi-stage air combustion nozzles 14 via a multi-stage combustion air control damper 13.
[0012]
The control device includes an input amount detection unit, a state amount detection unit, and a control unit. Input amount detecting means includes a sheet dust sensor 1 for shadow baked却物you pass the input chute 17 are attached to the chute 17 (size) and detect and passing speed output, the output of Kyujin sensor 1 And an arithmetic unit 2 that calculates and outputs the amount of waste input.
[0013]
The state quantity detection means includes an in-bed thermometer 3 for detecting and outputting the fluidized bed temperature, an in-furnace pressure gauge 4 for detecting and outputting the in-furnace pressure, and an in-furnace thermometer 5 for detecting and outputting the in-furnace temperature. An oxygen concentration meter 6 that measures and outputs the furnace outlet oxygen concentration, a nitrogen oxide concentration meter 7 that detects and outputs the amount of NOX generated, and a sulfur oxide concentration meter 8 that detects and outputs the amount of SOX generated , A carbon monoxide concentration meter 9 that detects and outputs the amount of CO generated, and a frame detector 10 that detects the luminance of the flame. The in-layer thermometer 3, the in-furnace pressure gauge 4, the in-furnace thermometer 5 and the frame detector 10 are mounted on the incinerator body 18, but the oxygen concentration meter 6, the nitrogen oxide concentration meter 7, the sulfur oxide concentration meter. 8. The carbon monoxide concentration meter 9 is attached to an exhaust duct 23 that extracts combustion exhaust gas from the incinerator body 18.
[0014]
The control means includes the arithmetic device 2, the in-layer thermometer 3, the in-furnace pressure gauge 4, the in-furnace thermometer 5, the oxygen concentration meter 6, the nitrogen oxide concentration meter 7, the sulfur oxide concentration meter 8, the carbon monoxide concentration. A discriminating device 11 that controls the operation of the fluidizing air control damper 12, the multistage combustion air control damper 13, and the switching dampers 15A and 15B using the output of the total 9 and the frame detector 10 as an input.
[0015]
The operation of the equipment having the above configuration will be described below. Garbage delivered from the dust feeder 16 passes through the input chute 17 and is input to the incinerator main body 18. At this time, the dust supply sensor 1 installed on the wall surface of the charging chute 17 detects the dust shadow (size) and the passing speed, and inputs the data to the arithmetic unit 2. The arithmetic device 2 calculates the input amount of garbage based on the input data, and outputs the obtained input amount to the determination device 11.
[0016]
Similarly, the fluidized bed temperature is measured with the in-bed thermometer 3, the pressure inside the incinerator with the pressure gauge 4 in the furnace, the temperature inside the incinerator with the temperature gauge 5, and incinerated with the oxygen concentration meter 6. Oxygen concentration at the furnace outlet, NOx generation amount in the incinerator with the nitrogen oxide concentration meter 7, SOX generation amount in the incinerator with the sulfur oxide concentration meter 8, and in the incinerator with the carbon monoxide concentration meter 9 The amount of CO generated is detected by the flame detector 10 and the brightness of the flame is detected and taken into the discriminator 11. The discriminating device 11 selects fluidized bed combustion or extra combustion based on preprogrammed conditions based on those data, and controls the switching dampers 15A and 15B to control the fluidized air supply duct 21 or multistage for extra combustion. Air is fed into one of the combustion air supply ducts 22. Further, the detection signals from the respective sensors are taken into the discriminating device 11 even after the start of the vertical combustion or the fluidized bed combustion, and the discriminating device 11 adjusts the optimal combustion air amount and the air distribution at that time respectively by the fluidizing air control damper 12. Alternatively, the control is performed by controlling the multistage combustion air control damper 13.
[0017]
A determination device determines which region of the plurality of predetermined regions the outputs of the arithmetic unit 2 and each sensor belong to, and thereby selects fluidized bed combustion or superficial combustion to control the air supply system. . In a normal state, fluidized-bed combustion is selected. However, when fluidized-bed combustion is selected, the switching damper 15B is naturally opened, and the fluidized air control damper 12 is opened, so that fluidized air enters the incinerator body 18. In-bed thermometer 3, furnace pressure gauge 4, furnace thermometer 5, oxygen concentration meter 6, nitrogen oxide concentration meter 7, sulfur oxide concentration meter 8, carbon monoxide concentration meter 9, frame The opening of the fluidized air control damper 12, the opening of the switching damper 15 </ b> A, and the opening of the multistage combustion air control damper 13 depend on which of the plurality of preset areas each output value of the detector 10 belongs to. Is set by the discrimination device.
[0018]
In addition, during the fluidized bed combustion, if the input amount of waste increases exceeding both the preset increase rate and the increase amount, the extra combustion is selected. When the vertical combustion is selected, the switching damper 15A is opened, the multistage combustion air control damper 13 is opened, air is supplied to the multistage combustion air nozzle 14, and the switching damper 15B is closed. As a result, the flow of the fluidized medium is stopped, and the dust is placed on the stationary fluidized medium by the air supplied through the multistage combustion air nozzle 14 and incinerated in a combustion state (a state where it does not flow). For example, when the waste supply amount temporarily increases beyond the preset rate of increase and the increase amount, the waste combustion is performed in such cases. As a result, the rapid progress of combustion and the generation of harmful gases can be prevented. Occurrence combustion deals with a case where the amount of waste input suddenly increases or a case where dust is gathered up and put in at once, and does not continue for a long time. If the amount of waste supply continues to exceed the preset value, the duster will reduce the supply amount, or fluidized air and / or secondary combustion air (air supplied from the multi-stage combustion air nozzle) Therefore, it is not necessary to select the long combustion for a long time, and the continuous combustion time may be several seconds to several minutes, at most about 10 minutes or less. The length of this time is set by a timer (not shown) built in the discrimination device 11.
[0019]
FIG. 2 shows an example of a control procedure when fluidized bed combustion and vertical combustion are switched.
[0020]
In the embodiment shown in FIG. 1, the fluidizing air supply duct 21 is provided with an annular fluidizing air header 25, and each fluidizing air nozzle 24 is connected to the fluidizing air header 25 with a fluidizing air header pipe 26. Connected through. Each fluidized valve in the air header pipe 26 is provided, if so adjusted based the opening of the stop valve on the output of the discriminating device 11, a portion of the baked却物causes the fluidized bed combustion, the other part Then, you can make it burn. This method is effective in the case where there is a difference in the properties of the waste to be charged, and the waste having a specific property is always deposited at a specific location in the furnace.
[0021]
【The invention's effect】
According to the present invention, it is possible to select a combustion mode suitable for the input amount of dust and the combustion state (combustion of either fluidized bed combustion, vertical combustion, or a combination of both), and the fluctuations in the amount of supplied dust and the amount of generated heat are large. Generation of harmful gases such as CO, NOX, and SOX generated during incineration of municipal waste is reduced.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of an incineration facility showing an embodiment of the present invention.
FIG. 2 is a procedure diagram showing an embodiment of a method for controlling an incinerator according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Dust supply sensor 2 Arithmetic unit 3 In-layer thermometer 4 In-furnace pressure gauge 5 In-furnace thermometer 6 Oxygen concentration meter 7 Nitrogen oxide concentration meter 8 Sulfur oxide concentration meter 9 Carbon monoxide concentration meter 10 Frame detector 11 Discriminator 12 Fluidized Air Control Damper 13 Multistage Combustion Air Control Damper 14 Multistage Combustion Air Nozzle 15A, 15B Switching Damper 16 Dust Feeder 17 Input Chute 18 Incinerator Body 19 Blower 20 Blower Discharge Duct 21 Fluidized Air Supply Duct 22 Multistage Combustion Air Supply Duct 23 Exhaust duct 24 Fluidized air nozzle 25 Fluidized air header 26 Fluidized air header piping

Claims (5)

Fluidized air is supplied to the fluidized bed, and secondary air for combustion is supplied to the upper part of the fluidized bed to detect the state quantity indicating the combustion state and the amount of incinerated material to be charged into the furnace. In the combustion method of the fluidized bed incinerator for controlling the supply of the fluidized air and the secondary air for combustion based on the detection result to burn the incinerator, the rate of increase in the input amount of the incinerator When both the increase amount and the preset value are larger than a preset value, the flow of the fluidized bed is stopped by controlling the supply of the fluidized air, and the flow is switched from the fluidized bed combustion to the combustion. Combustion method for floor type incinerator. The combustion method for a fluidized bed incinerator according to claim 1 , wherein a period for stopping the flow of the fluidized bed does not exceed 10 minutes. Fluidized air is supplied to the fluidized bed from the fluidized air duct through the fluidized air header, and the secondary air for combustion is supplied above the fluidized bed, and the state quantity indicating the combustion state and the state is introduced into the furnace. Of a fluidized-bed incinerator that detects the amount of incinerated material to be burned and controls the supply of the fluidized air and the secondary air for combustion based on the detection result to burn the incinerated material. A plurality of fluidized air nozzles for supplying the fluidized air to the fluidized bed are provided in a plurality of fluidized air pipes connected to the fluidized air header, and based on the detection result, the fluidized air A combustion method of a fluidized bed incinerator characterized by adjusting a degree of opening of a stop valve provided in an air pipe so that a part of the incinerated product is subjected to fluidized bed combustion and the other part is placed and combusted . Through a fluidizing air supply duct for supplying air to fluidize the fluidized medium in the fluidized bed, and the secondary air duct for combustion to supply the combustion secondary air above side of the fluidized bed, the chute into the incinerator state quantity detecting multiple state quantity indicating a paper dust machine for introducing material to be incinerated, and input amount detecting means for detecting an input amount before Symbol incinerated is placed in chute, the combustion state of the incinerated Te a detection means, and control means for controlling the output and the amount of air supplied to the fluidizing air supply duct and secondary air duct for the combustion output and input of the state quantity detecting means of the input amount detecting means, In the fluidized bed incinerator, the control means has the fluidized air supply duct when both the rate of change and the amount of change of the output of the input amount detecting means are larger than preset values. Close the damper provided on Fluidized bed incinerator, characterized. The state quantity detection means detects at least the fluidized bed temperature, furnace pressure, furnace temperature, furnace outlet oxygen concentration, NO x generation quantity, SO x generation quantity, CO generation quantity, and flame brightness . The fluidized bed incinerator according to claim 4, wherein the fluidized bed incinerator is a means .

Images