JP2543447B2 - Waste combustion boiler - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a waste combustion boiler for recovering as energy by using agricultural and forestry waste (hereinafter simply referred to as waste) such as bagasse, rice husks and wood chips as fuel.

[0002]

2. Description of the Related Art Conventionally, a waste combustion boiler of this type is known, for example, as shown in FIG. The waste combustion boiler 100 basically includes a combustion chamber 101,
Transfer floor grate 102 provided under this and waste A
A spreader (pneumatic spreader) 103 for spraying the air onto the transfer bed grate 102, a wind box 104 for supplying primary air B for combustion from below the transfer bed grate 102, and combustion promotion above the transfer bed grate 102. Therefore, the secondary air nozzle 105 for supplying the secondary combustion air C and the spreader air nozzle 106 for supplying a part of the combustion air from the spreader 103 as the spreader air D for spraying are configured. In the figure, 107 is a front wall water pipe, 108 is a rear wall water pipe, 109 is a side wall water pipe, 110 is a feeder, 111 is a chute, 112 is a boiler body, and 113 is a water seal conveyor. Thus, in such a product, the waste is spread by the spreader on the transfer grate and burned. However, recently, the dehydration rate of waste has been improved, the number of fine particles has increased, and the amount of floating combustion in the combustion chamber has increased.
For this reason, it is becoming less meaningful to burn a large amount of waste with large particles on a large transfer grate, and as the amount of ash on the transfer grate decreases, it is easily burned and stable combustion is performed. Without this, sufficient combustion efficiency could not be obtained.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and was devised in order to solve the problem. It is to provide a waste-fired boiler that can perform stable combustion even if the number of particles increases and improve combustion efficiency.

[0004]

The waste combustion boiler of the present invention basically comprises a relatively large combustion chamber, a relatively small fluidized bed provided in the lower portion of the combustion chamber, and a waste combustion chamber. Wind separation air that separates waste from the waste supply port and the waste from the waste supply port into fine particles and coarse particles and causes the fine particles to float and burn in the combustion chamber and to fluidize and burn the coarse particles in the fluidized bed. It is characterized by comprising a wind-selected air nozzle for supplying the air and a fluidized bed temperature maintaining device for maintaining the temperature of the fluidized bed constant regardless of the ratio of fine particles and coarse particles of waste.

[0005]

Function: Waste is supplied from the waste supply port to the combustion chamber. The supplied waste is sorted into fine particles and coarse particles by the air-selected air supplied from the air-selected air nozzle. The sorted fine particles are subjected to floating combustion in a relatively large combustion chamber, and the sorted coarse particles are fluidized to be burned in a relatively small fluidized bed. At this time, the fluidized bed temperature maintaining device maintains the temperature of the fluidized bed constant regardless of the ratio of the fine particles to the coarse particles of the waste.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic vertical sectional view showing a waste combustion boiler according to a first embodiment of the present invention. Waste combustion boiler 1
The combustion chamber 2, the fluidized bed 3, the waste material supply port 4, the wind-selected air nozzle 5, and the fluidized bed temperature maintenance device 6 constitute a main part of the. The combustion chamber 2 is relatively large and is formed by a front wall water pipe 7, a rear wall water pipe 8 and left and right side wall water pipes 9. The fluidized bed 3 is provided in the lower part of the combustion chamber 2 and is relatively small, and is provided via the inclined water pipe 10, and is provided with the fluidized sand 11 and the wind box 12 for supplying the flowing air E. There is. The waste material supply port 4 is configured to discharge the waste material A into the combustion chamber 2
Is provided in the front wall water pipe 7, and is connected to the feeder 14 via the chute 13. A primary air nozzle 15 for supplying the primary air B for combustion is concentrically provided on the outer peripheral portion of the waste supply port 4. Wind selection air nozzle 5
Is a wind selection in which the waste A from the waste supply port 4 is sorted into fine particles F and coarse particles G, the fine particles E are subjected to floating combustion in the combustion chamber 2, and the coarse particles F are fluidized and burned in the fluidized bed 3. It supplies the air C and is a secondary air nozzle that supplies secondary air for combustion, and the front wall water pipe 7 below the waste supply port 4
It is arranged so that the wind-selected air C is supplied substantially horizontally. The fluidized bed temperature maintenance device 6 keeps the temperature of the fluidized bed 3 constant regardless of the ratio of the fine particles F and the coarse particles G of the waste A. A lower waste supply port 16 for supplying a part to the fluidized bed 3, a waste distributor 17 for distributing the waste A to the waste supply port 4 and the lower waste supply port 16, and a temperature of the fluidized bed 3 Temperature detector 18 and a controller 19 for controlling the waste distributor 17 based on the temperature from the temperature detector 18. The lower waste supply port 16 is provided along the inclined water pipe 10 in the front wall water pipe 7 below the wind-selected air nozzle 5, and is connected to the middle of the chute 13 via the lower chute 20. The waste distributor 17 is a damper and is provided at a branch point between the chute 13 and the lower chute 20. Next, the operation will be described based on such a configuration. The waste A is supplied to the combustion chamber 2 from the waste supply port 4 via the feeder 1 and the chute 13. The supplied waste A is
The fine particles F and the coarse particles G are sorted by the wind-selected air C supplied from the wind-selected air nozzle 5. The fine particles F of the sorted waste A float and are burned in a floating manner in a relatively large combustion chamber 2, while the coarse particles G of the sorted waste A drop and fall in a relatively small fluidized bed 3. It is fluidized and burned. This time,
The fluidized bed temperature maintaining device 6 maintains the temperature of the fluidized bed 3 constant regardless of the ratio of the fine particles F and the coarse particles G of the waste A. That is, the temperature of the fluidized bed 3 is detected by the temperature detector 18, the controller 19 controls the waste distributor 17 based on the temperature detected by the temperature detector 18, and the waste distributor 17 discards it. The material A is distributed, one of the distributed wastes A is supplied from the waste supply port 4 to the combustion chamber 2, and the other distributed waste A is the lower waste supply port 16
Is directly supplied to the fluidized bed 3, and the temperature of the fluidized bed 3 is maintained constant. For example, when the amount of fine particles F of the waste A is large, the number of the coarse particles G falling into the fluidized bed 3 is small and the temperature of the fluidized bed 3 is lowered. Waste A is increased and fluidized bed 3
Temperature is kept constant.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the fluidized bed temperature maintaining device 6 is
A large number of air-selected air nozzles 5, an air controller 21 that collectively adjusts the air-selected air C from each air-selected air nozzle 5, a temperature detector 18 that detects the temperature of the fluidized bed 3, and a temperature detector. 1
It differs from the first embodiment in that it is configured with a controller 19 that controls the air conditioner 21 based on the temperature from 8. The air conditioner 21 is an air duct 2 connected to the wind-selected air nozzle 5.
It is provided in 2. In this way, the air conditioner 21
Thus, the pressure and amount of the wind-selected air C supplied from each wind-selected air nozzle 5 are collectively controlled in intensity, and the ratio of floating combustion and fluidized combustion can be controlled.

Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, the fluidized bed temperature maintaining device 6 is
A large number of air-selected air nozzles 5, an air controller 21 that individually adjusts the air-selected air C from each air-selected air nozzle 5, a temperature detector 18 that detects the temperature of the fluidized bed 3, and a temperature detector 18.
It differs from the second embodiment in that it is configured with a controller 19 that controls each air conditioner 21 based on the temperature from 1. The air conditioner 21 is provided in each of the air ducts 22 connected to each of the air-selection air nozzles 5. In this way, the pressure and amount of the wind-selected air C supplied from each wind-selected air nozzle 5 is individually controlled by the air conditioners 21 to form so-called jet zones and drop zones. It is possible to control the ratio between floating combustion and fluidized combustion.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In the third embodiment, the primary air B supplied from the primary air nozzle 15 is swirled, and the wind-selected air nozzle 5 is provided in the rear wall water pipe 8 below the waste supply port 4.
The third embodiment differs from the first embodiment in that a tertiary air nozzle 23 for supplying the tertiary air H for combustion is provided in the front wall water pipe 7 above the waste supply port 4. In FIG. 4, 2 is a combustion chamber, which is a front wall water pipe 7.
This is a space composed of the rear wall water pipe 8 and the left and right side wall water pipes 9, and the fluidized bed 3 is provided in the lower part via an inclined water pipe 10. The fluidized bed 3 has a cross-sectional area of 15 to 40 of the combustion chamber 2.
%, Superficial velocity 1 to 2 m / sec, sand height 200 to 5
It is set to 00 mm. Reference numeral 4 denotes a waste supply port, which has a double cylinder structure including an outer cylinder 24 and an inner cylinder 25. Inside the outer cylinder 24, swirl vanes (not shown) for the primary air B are provided or The primary air B is supplied tangentially.
Reference numeral 5 is a wind-selecting air nozzle that is provided 1 to 2 m below the waste supply port 4 so as to face it. 17 is a waste distributor for distributing waste A to the chute 13 and the lower chute 20;
Reference numeral 3 denotes a tertiary air nozzle for supplying the tertiary air H, which is provided 1 m or more above the waste supply port 4. Fluidized bed 3
Is composed of a fluidized sand 11, a wind box (fluidized air wind box) 12 and a fluidized nozzle, and a water pipe surrounding the fluidized bed 3 is covered with a wear and fire resistant material. The wind box 12 is provided with a starting oil burner 26 that supplies the starting oil I. A part of the fluidized bed 3 has a fluidized sand stationary portion 27 for removing incombustibles and foreign matters (stones, metals, etc.), and a sand discharging device 28, a sand sealing valve 29, and fluidized sand 11 at the bottom thereof. There is a screen 30 for separating foreign matter, and a sand feeding conveyor 31 for returning normal fluidized sand 11 into the fluidized bed 3. The air required for combustion is the pushing fan 32.
Through the air preheater 33, the wind box 12, the primary air nozzle 1
5, the air-selected air nozzle 5 and the tertiary air nozzle 23 are supplied. The pressure is supplied to the wind box 12 by the flow fan 34. Flowing air E is 15% of the air required for combustion.
-40%, primary air B is 40-60%, wind-selected air (secondary air) C is 20-25%, tertiary air H is 10-20%, and the excess air ratio is 1.4 or less. Exhaust gas (combustion gas) J is supplied from the downstream of the air preheater 33 to the recirculation fan 3
5 is sucked up to 30% or less and supplied to the wind box 12 together with the air from the flow fan 34. The fine particles F of the waste A supplied from the waste supply port 4 through the chute 13 are swirlingly supplied to the combustion chamber 2 by the primary air B swirling at high speed from the primary air nozzle 15. And burns floating. Due to the swirling flow of the primary air B, the fine particles F of the waste A are given a long residence time and are well mixed with air, so that stable combustion can be obtained. The swirling flow gradually weakens as it moves away from the waste supply port 4, but is mixed and agitated by the wind-selected air C supplied from the facing air-selected air nozzle 5 to promote floating combustion. The coarse particles G of the waste A that do not undergo floating combustion fall into the fluidized bed 3 and perform stable fluidized combustion in the fluidized bed 3 due to the fluidizing air E and the red-hot fluidized sand 11. The fluidized combustion gas containing residual oxygen after combustion rises and is used for combustion together with the primary air B and the wind-selected air C. The floating combustion gas and the fluid combustion gas are mixed and rise in the combustion chamber 2. However, since the tertiary air H is injected from the tertiary air nozzle 23, the floating unburned component and the volatile component are mixed and stirred to float. Combustion is promoted to complete combustion. When the property of the waste A is unstable and the rate of falling into the fluidized bed 3 is small and the temperature of the fluidized bed 3 cannot be controlled by the amounts of the fluidizing air E and the exhaust gas I, the combustion rate in the fluidized bed 3 is increased. Therefore, an appropriate amount of waste A can be dropped from the lower waste supply port 16 by the waste distributor 17, and the temperature of the fluidized bed 3 can be appropriately maintained. The fluidized bed 3 is controlled at a temperature of 650 to 900 ° C. The primary air B is the primary air damper 36.
Since the swirling force can be changed according to the increase / decrease of the air amount by the primary air damper 36, the waste A
It is possible to supply the combustion air suitable for the swirl floating combustion ratio and to adjust the ratio. Shoot 1
The angle α of 3 is preferably 40 to 60 degrees, which is equal to or greater than the repose angle of the waste A, and the position of the secondary air nozzle 5 is effectively 1 m or less from the waste supply port 4. The angle β of the inclined water pipe 10 is preferably 40 to 60 degrees, which is equal to or more than the angle of repose, in order to prevent the accumulated waste A and combustion ash from being deposited. As for the static sand thickness of the fluidized bed 3, the falling waste A is easily burnable with reduced water content in the swirling floating combustion section, so a shallow layer of 200 to 500 mm is sufficient. The flowing air E is 15 to 15% of the air required for combustion.
Since it is 40%, power up, which is a drawback of the fluidized bed 3, is small. Recirculation fan 35 is 30% of the total exhaust gas amount
And the capacity. In addition, 37 is a superheater, 38 is an economizer, 39 is a forced fan damper, 40 is a flow fan damper, 41 is a recirculation damper, 42 is a tertiary air damper, 43
Is a recirculation duct, and 44 is an induction fan.

[0010]

As described above, according to the present invention,
The following excellent effects can be achieved. (1) Composed of a combustion chamber, a fluidized bed, a waste supply port, a wind-selected air nozzle, and a fluidized-bed temperature maintenance device. Especially, the waste from the waste supply port depends on the wind-selected air from the wind-selected air nozzle. Air is separated into fine particles and coarse particles, and the fine particles are subjected to floating combustion in the combustion chamber and the coarse particles are fluidized and burned in the fluidized bed, so that floating combustion can be the main component, and the dehydration rate of waste Even if the number of particles increases and the number of fine particles increases, stable combustion is possible and combustion efficiency can be improved. (2) The wind-selected air from the wind-selected air nozzle is extremely rational because it uses secondary air for combustion. (3) The fluidized bed burns the waste which has been improved in dehydration rate and is light in weight, so that the fluidized bed can be a shallow bed and the pressure loss of the fluidizing air which is a drawback of the fluidized bed can be reduced. (4) Since the fluidized bed maintaining device is provided, the temperature of the fluidized bed can be kept constant even if the ratio of fine particles to coarse particles of the waste is not constant. (5) Do not use a spreader to supply waste,
Since a large transfer grate is not used, upsizing can be performed easily and maintenance is facilitated.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing a waste combustion boiler according to a first embodiment of the present invention.

FIG. 2 is a schematic vertical sectional view showing a waste combustion boiler according to a second embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing a waste combustion boiler according to a third embodiment of the present invention.

FIG. 4 is a schematic vertical sectional view showing a waste combustion boiler according to a fourth embodiment of the present invention.

FIG. 5 is a schematic vertical sectional view showing a conventional waste combustion boiler.

[Explanation of symbols]

 1 Waste Combustion Boiler 2 Combustion Chamber 3 Fluidized Bed 4 Waste Feeding Port 5 Wind-Selected Air Nozzle 6 Fluidized Bed Temperature Maintainer

Claims (4)

(57) [Claims] 1. A relatively large combustion chamber, a relatively small fluidized bed provided at the bottom of the combustion chamber, a waste supply port for supplying waste to the combustion chamber, and a waste from the waste supply port. A wind-selecting air nozzle that supplies wind-selected air that separates fine particles and coarse particles into floating combustion in the combustion chamber and also causes the coarse particles to flow and burn in a fluidized bed, and fine particles and coarse particles of waste. And a fluidized bed temperature maintaining device for maintaining a constant temperature of the fluidized bed regardless of the ratio of 2. A fluidized bed temperature maintaining device comprising a waste supply port, a lower waste supply port for supplying a part of waste to the fluidized bed, a waste supply port and a lower waste supply port. And a temperature detector for detecting the temperature of the fluidized bed, and a controller for controlling the waste distributor based on the temperature from the temperature detector. Item 1. A waste combustion boiler according to item 1. 3. A fluidized bed temperature maintaining device comprising a large number of air-selected air nozzles, an air controller for collectively adjusting the air-selected air from the respective air-selected air nozzles, and a temperature detector for detecting the temperature of the fluidized bed. The waste combustion boiler according to claim 1, wherein the waste combustion boiler comprises a controller and a controller for controlling the air conditioner based on the temperature from the temperature detector. 4. A fluidized bed temperature maintaining device comprising a plurality of air-selected air nozzles, an air controller for individually adjusting air-selected air from each air-selected air nozzle, and a temperature detector for detecting the temperature of the fluidized bed. The waste combustion boiler according to claim 1, further comprising: a controller for controlling each air conditioner based on the temperature from the temperature detector.