JPH08278004A - Secondary combustion device - Google Patents

Abstract

PURPOSE: To provide a further complete combustion state by mounting a secondary combustion device on a general combustion device. CONSTITUTION: By guiding non-reaction gas 37, generated at the outside, from a gas inlet part 38 in the direction of an internal tangential line, the swirl rise flow of the non-reaction gas 37 is generated in a secondary combustion device body 34 having a cylindrical side wall. Powder/grain 41 accumulated at a hopper 36 at the lower part of the secondary combustion device body 34 is blown up and circulated by means of the non-reaction gas 37 introduced through a gas inlet part 38.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary combustion device.

[0002]

2. Description of the Related Art For example, a combustion device such as a waste incinerator is
Generally, municipal waste and other wastes are put into a combustion chamber and burned. Inside the combustion chamber, there are two processes, that is, thermal decomposition of the waste and combustion of combustible gas generated by the thermal decomposition. , The waste is being burned.

However, in the conventional combustion apparatus, since two kinds of reactions, that is, thermal decomposition of waste and combustion of combustible gas, are simultaneously performed in one combustion chamber, thermal decomposition of waste is also
Combustible gas combustion also tended to be insufficient.

For example, in the thermal decomposition of waste, it is easy to lose the thermal decomposition rate due to the temperature change due to the influence of combustion of combustible gas.

Further, in the combustion of combustible gas, sufficient mixing of air cannot be obtained in the combustion chamber, the combustible gas causes incomplete combustion and toxic substances are easily generated, and the toxic substances are directly discharged to the atmosphere. There was a risk of being

Therefore, in recent years, an existing combustion chamber is used as a primary combustion chamber, and a secondary combustion chamber is attached to the primary combustion chamber to allow the primary combustion chamber to perform thermal decomposition of wastes only, and to combustible gas generated by thermal decomposition. A combustion apparatus has been proposed in which the combustible gas is guided to the secondary combustion chamber and completely combusted in the secondary combustion chamber.

FIG. 7 shows a currently proposed combustion apparatus having a secondary combustion chamber.

In the figure, 1 is a primary combustion chamber in which a waste supply port 2 is formed in the upper part and a hopper part 3 is formed in the lower part, and 4 are arranged at intervals above the hopper part 3 of the primary combustion chamber 1. A plurality of horizontal air diffusers 5 are fluidized beds formed by a fluidized medium such as fluidized sand and flowed by the air jetted from the air diffusers 4, 6 is a fluidized bed 5 in the middle of the primary combustion chamber 1. It is a burner installed toward.

7 is a fluid medium outlet provided at the lower end of the hopper 3, 8 is a fluid medium inlet formed in the intermediate portion of the primary combustion chamber 1, 9 is a space between the fluid medium outlet 7 and the fluid medium inlet 8. Fluid medium circulation path such as connecting bucket conveyor, 10
Is a fluid medium conveyor provided on the inlet side of the fluid medium circulation path 9, and 11 is a sieving device provided on the outlet side of the fluid medium conveyor 10.

Reference numeral 12 is a secondary combustion chamber which is disposed above the primary combustion chamber 1 and has a combustion gas discharge port 13 at its upper end and a hopper portion 14 at its lower end, and 15 is a primary combustion chamber. Combustible gas containing solid unburned matter 16 generated in the chamber 1, 1
Reference numeral 7 is an ash outlet formed at the lower end of the hopper portion 14.

Further, 18 is a flow passage for sending the combustible gas 15 from the primary combustion chamber 1 to the secondary combustion chamber 12, and 19 is tangentially connected to the lower side wall of the secondary combustion chamber 12. A tangential connection.

Reference numeral 20 is an air supply path connected to an external fan 21, 22 is a primary air supply path branched from the air supply path 20 to supply air to the diffuser pipe 4, and 23 and 24 are from the air supply path 20. Secondary air supply passages 25, 2 which are branched to supply air to several positions of the squeezing passage 18.
Reference numerals 6 and 27 are valves provided in the middle of the primary air supply passage 22 and the secondary air supply passages 23 and 24, respectively.

Then, the air blower 21 is operated to supply air to the diffuser pipe 4 of the primary combustion chamber 1 through the air supply passage 20 and the primary air supply passage 22, thereby causing the fluidized bed 5 to flow and The fluidized bed 5 in the primary combustion chamber 1 is preheated by the burner 6, and in this state, the waste is introduced into the primary combustion chamber 1 from the waste supply port 2.

Then, the waste material charged into the primary combustion chamber 1 is pyrolyzed in the preheated fluidized bed 5, and combustible gas 15 and solid unburned matter 16 such as char (char) are decomposed by the pyrolysis. Is generated.

The solid unburned matter 16 such as char is burned by the air supplied from the air diffuser 4 to the primary combustion chamber 1, and the thermal decomposition of the solid matter 16 promotes the thermal decomposition of the waste.

The combustible gas 15 generated by the thermal decomposition of the waste rises, and the squeezing passage 18 and the tangential connection 19 are provided.
Through the secondary combustion chamber 12, the waste can be thermally decomposed at a constant rate in the primary combustion chamber 1 without being affected by the combustion of the combustible gas 15.

On the other hand, the squeezing passage 18 and the tangential connecting portion 1
The combustible gas 15 sent to the secondary combustion chamber 12 through 9
A portion of the solid unburned matter 16 is supplied with air from the secondary air supply passages 23 and 24 in the squeezing passage 18 on the way, and after being mixed to some extent, into the substantially cylindrical secondary combustion chamber 12. Introduced tangentially.

Then, in the secondary combustion chamber 12, a swirl flow is formed by the combustible gas 15 mixed with air, and the swirl flow further promotes the mixing of the combustible gas 15 and air. In addition, since the residence time required for the combustion of the combustible gas 15 inside the secondary combustion chamber 12 is sufficiently secured by the swirling, the combustible gas 15 is completely combusted during that time, and harmful substances due to incomplete combustion are generated. Occurrence is suppressed.

The combustion gas produced by the combustion is discharged from the combustion gas discharge port 13 at the upper end of the secondary combustion chamber 12.

Separately from the above, in the primary combustion chamber 1, a part of the fluidized medium forming the fluidized bed 5 is passed from the fluidized medium outlet 7 at the lower end of the hopper 3 to the sieve device 11 via the fluidized medium conveyor 10. After the incombustibles are removed by the sieving device 11, the fluid is circulated from the fluidized medium inlet 8 to the primary combustion chamber 1 via the fluidized medium circulation passage 9.

Further, the solid unburned matter 16 that has been entrained in the combustible gas 15 and has risen in the squeezing passage 18 is centrifugally separated by a swirling flow in the secondary combustion chamber 12 and is converted into ash content in the secondary combustion chamber 12
It is discharged from the ash outlet 17 at the lower end of the hopper portion 14.

[0022]

However, the secondary combustion chamber in the above combustion device has the following problems.

That is, the thermal decomposition of waste is carried out in the primary combustion chamber 1,
Further, when the combustion of the combustible gas 15 is performed exclusively in the secondary combustion chamber 12, it becomes possible to burn the waste in a state close to the complete combustion, but the upper end of the secondary combustion chamber 12 The combustion gas discharged from the combustion gas discharge port 13 still contains about 9 ppm of carbon monoxide. This is because the solid unburned components 16 contained in the combustible gas 15 are not completely burned in the secondary combustion chamber 12, and there is room for further improving the combustion state in the secondary combustion chamber 12.

In view of the above situation, it is an object of the present invention to provide a secondary combustion device that can obtain a more complete combustion state when attached to a general combustion device. It is another object of the present invention to provide a secondary combustion device capable of effectively controlling the concentration of nitrogen oxides to fall within the reference range.

[0025]

According to the present invention, a gas inlet capable of introducing an unreacted gas containing a solid unburned component in an inner tangential direction to a lower portion of a side wall of a secondary combustion apparatus main body having a cylindrical side wall. Part of the secondary combustion device main body, and powder particles were deposited on the hopper formed below the gas inlet of the main body of the secondary combustion device to a height at which it could be blown up by the unreacted gas introduced from the gas inlet. And a secondary combustion device characterized by the above.

In this case, the gas inlet may be arranged so as to be inclined downward so as to face the powder or granular material accumulated in the hopper.

Further, the secondary combustion device main body is provided with a powder / granular material supply device having a powder / granular material supply valve, and a powder / granular material level adjusting valve is provided at the lower end of the hopper portion so that the powder / granular material can be taken out of the system. In addition to the automatic discharge mechanism, a temperature measuring device is installed in the main body of the secondary combustion device, and the temperature measuring signal measured by the temperature measuring device is compared with the reference temperature input to the input setting device, and the particulate material supply valve An arithmetic and control unit may be provided which sends a control signal for feeding the powder or granular material or a control signal for causing the powder or granular material level adjusting valve to withdraw the powder or granular material out of the system.

Further, the powder and granular material supply device having the powder and granular material supply valve is attached to the main body of the secondary combustion device, and the carbon monoxide concentration detector is provided at the gas outlet portion of the main body of the secondary combustion device.
Computation of sending a control signal to feed the granular material into the particulate material supply valve by comparing the carbon monoxide concentration detection signal detected by the carbon monoxide concentration detector with the reference carbon monoxide concentration input to the input setting device. A control device may be provided.

Furthermore, a denitration agent supply device equipped with a denitration agent supply valve is attached to the main body of the secondary combustion device, and a nitrogen oxide concentration detector is provided at the gas outlet portion of the main body of the secondary combustion device. Provide an arithmetic and control unit that compares the nitrogen oxide concentration detection signal detected by the concentration detector with the reference nitrogen oxide concentration input to the input setting device, and sends a control signal to feed the denitration agent to the denitration agent supply valve. You can

[0030]

The operation of the present invention is as follows.

The unreacted gas in an incompletely burned state is tangentially introduced into the substantially cylindrical secondary combustion apparatus main body through the gas inlet portion.

When introduced from the tangential direction, the unreacted gas becomes a swirling upward flow along the side wall of the main body of the secondary combustion device.

At this time, by depositing the granular material in the hopper portion at the lower part of the main body of the secondary combustion device, the deposited granular material is rolled up by the introduced unreacted gas and is entrained in the swirling upward flow. Will be raised. In addition, by arranging the gas inlet portion in a downward inclined manner, the amount of powder particles scattered in the furnace increases.

The swirl upward flow ensures a sufficient retention time of the unreacted gas inside the main body of the secondary combustion device.

By ensuring a sufficient residence time, the unreacted gas is completely combusted and the generation of harmful substances such as dioxins due to incomplete combustion is suppressed.

Similarly, the solid unburned content such as char that has entered the main body of the secondary combustion apparatus together with the unreacted gas from the gas inlet is
The unreacted gas is swirled up along the inner wall of the secondary combustion device body along with the swirl upflow.

Then, the solid unburned component which is increased by being entrained in the unreacted gas is separated from the unreacted gas when the flow velocity of the swirling flow of the unreacted gas is reduced in the upper part of the main body of the secondary combustion device,
It falls by its own weight and is again entrained in the swirl flow having a high flow velocity on the upstream side and rises, and is circulated in the main body of the secondary combustion device, whereby the solid unburned components are circulated in the main body of the secondary combustion device. An internal circulation flow is formed.

By this internal circulation flow, the residence time of the solid unburned matter in the furnace is sufficiently lengthened, so that the combustion state of the solid unburned matter is improved.

Moreover, due to the centrifugal force of the swirling flow, the solid unburned components are gathered along the inner wall of the main body of the secondary combustion device, and in the high concentration particles of the solid unburned component thus formed along the inner wall, By the granular material that is blown up by the unreacted gas and is circulated along with the solid unburned matter on the internal circulation flow,
Since the surface of the solid unburned matter is peeled off and a new surface is constantly exposed, combustion of the solid unburned matter is promoted.

As described above, even if the solid unburned matter is flame-retardant, a more complete combustion state (higher by one digit or more) is achieved,
Conventionally, the combustion gas discharged from the combustion gas outlet at the upper end of the main body of the secondary combustion device still contains about 9 ppm of carbon monoxide. It becomes possible to drop carbon to a level of 1 ppm or less and very close to 0 ppm.

In addition, the solid unburned matter and the granular material flow intensively along the side wall of the secondary combustion device body due to the centrifugal force, so that the inside of the secondary combustion device body is cleaned. Can also be obtained.

The structure of depositing powder particles on the hopper of the present invention is particularly suitable when the main body of the secondary combustion device is small.

By the way, the height level of the granular material accumulated in the hopper and the amount of the granular material scattered in the furnace are sufficient to obtain a good combustion state as described above, without any particular control. However, in order to further improve the combustibility, the following control can be performed.

That is, in the temperature measuring device, the temperature of the part at the same height level as the mounting position of the gas inlet part in the lower part of the side wall of the main body of the secondary combustion device (this part has the highest temperature).
Is measured, and the temperature measurement signal measured by the temperature measurement device is sent to the arithmetic and control unit, and the arithmetic and control unit compares it with the input signal such as the reference temperature from the input setting unit.

Then, as a result of the comparison, when the value of the temperature measurement signal measured by the temperature measuring device is higher than the reference temperature,
Solid unburned matter such as char with a low melting point introduced with unreacted gas, ash introduced into the secondary combustion device main body together with solid unburned matter, ash produced by burning solid unburned matter, etc. There is a risk of melting and adhering to the inner wall, so the arithmetic and control unit sends a control signal to the powder and granular material supply valve to open the powder and granular material supply valve, and the cold powder and granular material in the powder and granular material supply device is opened in the hopper section. By dropping a large amount of it into the furnace, the temperature inside the furnace is lowered, and the melting and adhesion of solid unburned matter and ash is prevented.

When the powder and granular material supply device is provided at a position along the furnace wall at the upper end of the main body of the secondary combustion device, the powder and granular materials are dropped along the inner wall of the main body of the secondary combustion device. A cleaning effect inside the main body of the secondary combustion device can also be expected.

Generally, when the temperature in the furnace becomes higher, the amount of nitrogen oxides tends to increase. However, by dropping a large amount of cooled powder or granules to lower the temperature in the furnace, the nitrogen oxide is simultaneously oxidized. It is possible to suppress the generation of objects.

On the contrary, if the value of the temperature measurement signal measured by the temperature measuring device is lower than the reference temperature, it indicates that the combustion efficiency of the main body of the secondary combustion device tends to decrease. Sends a control signal to the granular material level adjusting valve, and sends the air from the blower to the extraction mechanism via the extraction air supply path to discharge the granular material of the hopper out of the system, The amount of powder particles accumulated in the hopper is reduced and the temperature inside the furnace is increased to improve combustion efficiency.

Further, in general, when the temperature in the furnace becomes low, the amount of carbon monoxide generated tends to increase, so the arithmetic and control unit sends a control signal to the powder and granular material supply valve to turn the powder and granular material supply valve on. Open and drop a small amount of powder in the powder feeder to the hopper to increase the amount of powder in the furnace.
It is also possible to promote the combustion of the solid unburned component and suppress the generation of carbon monoxide.

Similarly, the concentration of carbon monoxide is detected by the carbon monoxide concentration detector provided at the combustion gas outlet of the main body of the secondary combustion device, and the carbon monoxide concentration is detected by the carbon monoxide concentration detector. The signal is sent to the arithmetic and control unit, and the arithmetic and control unit
It is compared with the input signal such as the reference carbon monoxide concentration from the input setting device.

As a result of the comparison, when the value of the carbon monoxide concentration detection signal is larger than the reference carbon monoxide concentration,
Since it indicates that the amount of powder particles scattered in the furnace is insufficient and the combustibility of the solid unburned matter is reduced, the arithmetic and control unit sends a control signal to the powder particle supply valve to supply the powder particles. By opening the valve and dropping a small amount of the granular material in the granular material supply device to the hopper, the amount of the granular material scattered in the furnace is increased, and the decomposition and combustion of the solid unburned matter is promoted.

Contrary to the above, when the value of the carbon monoxide concentration detection signal is smaller than the reference carbon monoxide concentration,
Since it shows that the combustion state is good, no particular control is required.

Similarly, the concentration of nitrogen oxides is detected by a nitrogen oxide concentration detector provided at the combustion gas discharge port of the main body of the secondary combustion device, and the nitrogen oxide concentration is detected by the nitrogen oxide concentration detector. The signal is sent to the arithmetic and control unit, and the arithmetic and control unit
It is compared with the input signal such as the reference nitrogen oxide concentration from the input setting device.

As a result of the comparison, when the value of the nitrogen oxide concentration detection signal is larger than the reference nitrogen oxide concentration,
The arithmetic control device sends a control signal to the denitration agent supply valve to inject the denitration agent of the denitration agent supply device into the furnace to reduce nitrogen oxides.

On the contrary to the above, when the value of the nitrogen oxide concentration detection signal is smaller than the reference nitrogen oxide concentration,
Since it shows that the combustion state is good, no particular control is required.

[0056]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 6 show an embodiment of the present invention.

In the figure, 28 is the primary combustion device, and 29 is the fuel supplied to the primary combustion device 28. Here, the primary combustion device 28 is not limited to the fluidized bed type combustion furnace as shown in FIG. 7, but a combustion device that generates combustion gas, such as a stoker type combustion furnace, a boiler, or a large diesel engine, can be widely applied. Is.

Reference numeral 30 is an air supply passage for supplying air from an external fan 31, 32 is a primary air supply passage branched from the air supply passage 30, for supplying air to the primary combustion device 28, 33 Is a valve provided in the middle of the primary air supply passage 32.

Then, as shown in FIG. 2, an independent secondary combustion device body 34 having a cylindrical side wall is provided in parallel above or to the side of the primary combustion device 28, and the secondary combustion device body 34 is A combustion gas discharge port 35 is formed at the upper axial center position, and a hopper portion 36 is formed below the secondary combustion device body 34.

Further, the primary combustion device 2 is provided between the upper part of the primary combustion device 28 and the lower part of the side wall of the secondary combustion device body 34.
A gas inlet portion 38 for guiding the unreacted gas 37 (gas before undergoing the reaction performed in the secondary combustion device body 34) generated in 8 to the secondary combustion device body 34 is connected. The gas inlet portion 38 is connected to the main body 34 of the secondary combustion device in a tangential direction, and is connected with a downward slope if necessary. The angle θ of the gas inlet portion 38 is optimally about 30 degrees.

Reference numeral 39 is a secondary air supply passage branched from the air supply passage 30 for supplying air to the gas inlet portion 38, and 40 is a valve provided in the middle of the secondary air supply passage 39. .

In the present embodiment, the granular material 41 is deposited on the hopper portion 36 of the main body 34 of the secondary combustion device to the height level of the gas inlet portion 38, and at the lower end of the hopper portion 36 of the main body 34 of the secondary combustion device. An extraction mechanism 42 such as an L-shaped valve for extracting the powder or granular material 41 to the outside is attached, and an extraction air supply passage 43 is provided between the air supply passage 30 and the extraction mechanism 42 such as an L-shaped valve. And a powder or granular material level adjusting valve 44 is provided in the middle of the extraction air supply passage 43.

Here, as the granular material 41 to be deposited on the hopper portion 36, fluidized sand such as normal sand or silica sand, desulfurizing agent particles, denitration agent particles, or desulfurizing agent particles in the fluidized sand or the like is used. A mixture of denitration agent particles can be used.

When the primary combustion device 28 is a fluidized bed type, the powder particles 41 are made the same as the fluidized sand of the primary combustion device 28, and the powder particles 41 extracted from the extraction mechanism 42 are indicated by arrows 4
As shown by 5, it may be sent to the primary combustion device 28.

Further, in the main body 34 of the secondary combustion apparatus, a powder / granular material supply valve 47 (which is used as a denitrifying agent supply valve in some cases) is used to supply a powder / granular material supply device 47 such as a powder / granular material supply hopper (in some cases, denitration). (Used as an agent supply device).
The position of attachment of the powder and granular material supply device 47 is arbitrary, but in order to obtain a cleaning effect, it is preferable that it is at the upper end of the secondary combustion device body 34 and along the furnace wall of the secondary combustion device body 34. .

Then, the granular material level measuring device 48 is attached to the hopper portion 36 where the granular material 41 is accumulated, and the level is almost the same as the mounting position of the gas inlet portion 38 in the lower side wall of the secondary combustion device main body 34. The temperature measuring device 49 is attached so that

Although the mounting position of the temperature measuring device 49 is arbitrary, the above-mentioned position is preferable because the temperature of the secondary combustion device main body 34 becomes the highest.

If necessary, the secondary combustion device main body 34
A carbon monoxide concentration detector 5 is provided at the combustion gas discharge port 35 at the upper end.
0 or nitrogen oxide concentration detector 51 is attached.

The carbon monoxide concentration detector 50 and the nitrogen oxide concentration detector 51 may be mounted at any positions, but the above positions are most preferable. Further, since the control by these is partially overlapped with the control by the temperature measuring device 49, it may not be provided at all, or only one of them may be provided.

Furthermore, the granular material level signal 52 from the granular material level measuring device 48, the temperature measuring signal 53 from the temperature measuring device 49, and the carbon monoxide concentration detecting signal 54 from the carbon monoxide concentration detector 50. And a nitrogen oxide concentration detection signal 55 from the nitrogen oxide concentration detector 51, and various inputs such as a reference level, a reference temperature, a reference carbon monoxide concentration and a reference nitrogen oxide concentration from the input setting device 56. Compared with the signal 57, the control signal 58 is sent to the powder level control valve 44, the control signal 59 is sent to the powder supply valve 46, and
If necessary, the arithmetic and control unit 60 is provided which sends a control signal 75 to a flow rate adjusting valve 73 (denitration agent supply valve) described later.

The reference level, the reference temperature, the reference carbon monoxide concentration, the reference nitrogen oxide concentration and the like may be specified values or values having a range by setting an upper limit value and a lower limit value.

Further, a complete combustion zone 61 is formed below the side wall of the secondary combustion apparatus main body 34, and a chemical reaction zone 62 is formed above it. Incidentally, in this embodiment, the unreacted gas 3
No. 7 is set so as to pass through the secondary combustion apparatus main body 34 in about 2 seconds, of which the complete combustion zone 61 is the first up to about 1.5 seconds, and the remaining 0.5 seconds. Is the drug reaction zone 62.

At the boundary position between the lower complete combustion zone 61 and the upper chemical reaction zone 62 on the side wall of the secondary combustion apparatus body 34, a chemical agent 63 such as a denitration agent or a desulfurizing agent is added to the secondary combustion apparatus body 34. A drug injection nozzle 64 capable of jetting and supplying toward the axial center position is attached, and the drug injection nozzle 6
4, a flow rate adjusting valve 73 (denitration agent supply valve), a flow rate adjusting valve 74
A denitration agent tank 65 (denitration agent supply device) and a desulfurization agent tank 66 (desulfurization agent supply device) are connected via a (desulfurization agent supply valve). However, the chemical injection nozzle 64 may be provided individually for each denitration agent or desulfurization agent, and may be capable of injecting a chemical agent other than the above. It should be noted that when denitration agent particles, desulfurization agent particles, or the like are used as the powder particles 41, or when desulfurization agent particles, denitration agent particles, or the like are mixed with the powder particles 41, it is not particularly necessary to provide them.

In the figure, 67 is a solid unburned component such as char contained in the unreacted gas 37 generated in the primary combustion device 28 (some may include ash).

Further, 68 is an exhaust gas duct connected to the combustion gas exhaust port 35, 69 is a heat recovery device provided in the middle of the exhaust gas duct 68, and 70 is provided downstream of the heat recovery device 69 as required. A dust collector 71 is a chimney provided on the outlet side of the dust collector 70 for discharging the exhaust gas 72 to the atmosphere.

Next, the operation will be described.

Air from the ventilator 31 is supplied to the primary combustion device 28 through the air supply passage 30 and the primary air supply passage 32 to burn the fuel 29.

The unreacted gas 37 in the incompletely burned state generated as a result of combustion in the primary combustion device 28 is
Ventilation that is tangentially and downwardly sent to the main body 34 of the secondary combustion device through the shaft 8 at an angle of approximately 30 degrees, and is then supplied through the air supply passage 30 and the secondary air supply passage 39. Air from machine 31 is mixed.

The components of the unreacted gas 37 generated in the primary combustion device 28 are the types of the primary combustion device 28, such as the fluidized bed combustion furnace, the stoker combustion furnace, the boiler, the large diesel engine, and other combustion. It depends on the device.

Further, in the present invention, since the powder particles 41 are deposited in the hopper portion 36 up to a height near the gas inlet portion 38, the unreacted gas 37 is introduced tangentially downward, so that the secondary gas Inside the combustion device main body 34, first, the powder or granular material 41 accumulated in the hopper portion 36 is hit and blown up, and then, as shown in the graph of FIG. 3, along the side wall of the secondary combustion device main body 34. It becomes a swirling upward flow.

When the gas inlet portion 38 is directed downward, the amount of powder 41 dispersed in the furnace can be increased.
Even if it is horizontal, the particles 41 are blown up to a necessary and sufficient extent.

The unreacted gas 37 is generated by the swirling upward flow.
And mixing with air is further promoted. Further, the unreacted gas 3 inside the main body 34 of the secondary combustion device is swirled.
The residence time of 7 is sufficiently secured.

As a result, the unreacted gas 37 is completely combusted, and the generation of harmful substances such as dioxins due to incomplete combustion is suppressed.

The unreacted gas 37 is the secondary combustion apparatus main body 3
The time for passing through the inside of the No. 4 is set to about 2 seconds, and the unreacted gas 37 is completely combusted during the complete combustion zone 61 of the first about 1.5 seconds.

Similarly, the unreacted gas 3 is fed from the gas inlet portion 38.
The solid unburned component 67 such as char that has entered the secondary combustion device body 34 together with 7 is entrained in the swirl upward flow of the unreacted gas 37 and swirled up along the inner wall of the secondary combustion device body 34.

Then, the solid unburned matter 67 that has risen along with the unreacted gas 37 is separated from the unreacted gas 37 when the flow velocity of the swirling flow of the unreacted gas 37 decreases in the upper portion of the secondary combustion apparatus main body 34. It is circulated inside the secondary combustion device main body 34 such that it falls under its own weight and is again accompanied by a swirling flow having a high flow velocity on the upstream side and rises. An internal circulation flow of unburned matter 67 is formed.

Due to this internal circulation flow, solid unburned matter 67
Since the residence time in the furnace is sufficiently long,
The combustion state of is improved.

Moreover, due to the centrifugal force of the swirling flow, as shown in the graph of FIG. 4, the solid unburned matter 67 gathers along the inner wall of the secondary combustion apparatus main body 34, and the solid unburned matter thus formed along the inner wall. In the high-concentration particle group of the fuel 67, the powder 41 that is blown up by the unreacted gas 37 and is circulated along with the solid unburned fuel 67 on the internal circulation flow,
Since the surface of the solid unburned matter 67 is peeled off so that a new surface is always exposed, combustion of the solid unburned matter 67 is promoted.

As described above, even if the solid unburned matter 67 is flame-retardant, a more complete (higher than one digit) combustion state is achieved. In the conventional case of FIG. , 3
4, the combustion gas discharged from the combustion gas discharge ports 13 and 35 at the upper end still contains about 9 ppm of carbon monoxide as shown by the line C in FIG. 6. In the case of the present invention, As indicated by the line D, the carbon monoxide in the combustion gas is
It is possible to drop to a level below ppm and very close to 0 ppm.

In addition, the solid unburned matter 67 and the powder and granules 41 are
As shown in the graph of FIG. 4, centrifugal force causes concentrated flow along the side wall of the secondary combustion device main body 34, so that the effect of cleaning the inside of the secondary combustion device main body 34 is also obtained.

The structure in which the powder particles 41 are deposited on the hopper portion 36 of the present invention is particularly suitable when the secondary combustion apparatus main body 34 is small.

By the way, the height level of the powder or granules 41 deposited on the hopper portion 36 and the amount of the powder or granules 41 scattered in the furnace can obtain a good combustion state as described above without any particular control. However, in order to further improve the combustibility, the following control can be performed.

That is, the temperature measuring device 49 measures the temperature of the portion at the same height level as the mounting position of the gas inlet portion 38 under the side wall of the secondary combustion device main body 34 (this portion has the highest temperature). The temperature measurement signal 53 measured by the temperature measurement device 49 is sent to the arithmetic and control unit 60, and the arithmetic and control unit 60 compares it with the input signal 57 such as the reference temperature from the input setting unit 56.

As a result of the comparison, when the value of the temperature measurement signal 53 measured by the temperature measuring device 49 is higher than the reference temperature, solid unburned components such as char having a low melting point introduced together with the unreacted gas 37. 67, ash introduced into the secondary combustion device main body 34 together with the solid unburned matter 67, and solid unburned matter 6
The ash and the like formed by burning 7 may melt and adhere to the inner wall.
6 to send the control signal 59 to the powder and granular material supply valve 46 to open the cooled granular and granular material 41 in the powder and granular material supply device 47.
By dropping a large amount of
It prevents fusion of solid unburned matter 67 and ash.

When the powder and granular material supply device 47 is provided at a position along the furnace wall at the upper end of the secondary combustion device body 34, the powder and granular material 41 falls along the inner wall of the secondary combustion device body 34. By doing so, a cleaning effect inside the secondary combustion device main body 34 can also be expected.

In general, when the temperature inside the furnace becomes higher, the amount of nitrogen oxides tends to increase. However, by dropping a large amount of the cooled powder or granules 41 to lower the temperature inside the furnace, the nitrogen is simultaneously discharged. Generation of oxide can be suppressed. Moreover,
When the dropped particles 41 are denitration agent particles, or when the particles 4
When the denitration agent particles are mixed with 1, denitrification agent particles also have the effect of reducing nitrogen oxides. If the powder 41 does not contain denitration agent particles, the arithmetic and control unit 60
It is also possible to send a control signal 75 to the flow rate adjusting valve 73 (denitrification agent supply valve) to inject the denitrification agent in the denitration agent tank 65 from the agent injection nozzle 64 into the furnace.

On the other hand, when the value of the temperature measurement signal 53 measured by the temperature measuring device 49 is lower than the reference temperature, it indicates that the combustion efficiency of the secondary combustion device body 34 tends to decrease. The arithmetic and control unit 60 sends a control signal 58 to the powdery or granular material level adjusting valve 44 so that the air from the air blower 31 is extracted through an extraction air supply passage 43 such as an L-shaped valve.
By sending the powder particles 41 of the hopper 36 to the outside of the system, the amount of the particles 41 accumulated in the hopper 36 is reduced, the temperature in the furnace is increased, and the combustion efficiency is improved. .

Further, in general, when the temperature inside the furnace becomes low, the amount of carbon monoxide generated tends to increase. Therefore, the arithmetic and control unit 60 sends a control signal 59 to the powder and granular material supply valve 46 to supply the powder and granular materials. By opening the valve 46 and dropping a small amount of the powder / granular material 41 in the powder / granular material supply device 47 to the hopper portion 36, the amount of the powder / granular material 41 scattered in the furnace is increased, and the combustion of the solid unburned matter 67 is promoted. It is also possible to suppress the generation of carbon monoxide.

Similarly, the concentration of carbon monoxide is detected by the carbon monoxide concentration detector 50 provided at the combustion gas discharge port 35 of the secondary combustion apparatus main body 34, and the carbon monoxide concentration detector 50 detects the concentration. The control unit 60 calculates the carbon oxide concentration detection signal 54.
Then, the arithmetic and control unit 60 compares it with the input signal 57 such as the reference carbon monoxide concentration from the input setting unit 56.

Then, as a result of the comparison, when the value of the carbon monoxide concentration detection signal 54 is larger than the reference carbon monoxide concentration, the amount of the particles 41 scattered in the furnace is insufficient and the solid unburned matter 67
Since it indicates that the combustibility of the powder is reduced, the arithmetic and control unit 60 sends a control signal 59 to the powder and granular material supply valve 46,
By opening the granular material supply valve 46 and dropping the granular material 41 in the granular material supply device 47 to the hopper unit 36 in a small amount,
The amount of powder particles 41 scattered in the furnace is increased, and the decomposition and combustion of the solid unburned matter 67 is promoted.

Further, as described above, when the amount of carbon monoxide generated increases, the temperature inside the furnace may be lowered. Therefore, by reducing the deposition amount of the powder or granular material 41 in the hopper section 36, The temperature inside the furnace may be raised.

Contrary to the above, when the value of the carbon monoxide concentration detection signal 54 is smaller than the reference carbon monoxide concentration, it indicates that the combustion state is good, and therefore, the control is particularly performed. No need. Alternatively, during this time, the hopper 36
It is also possible to adjust the level of the powder and granules 41 in step 1 to the reference level.

Similarly, the nitrogen oxide concentration detector 51 provided at the combustion gas discharge port 35 of the secondary combustion apparatus main body 34 detects the concentration of nitrogen oxides, and the nitrogen oxide concentration detector 51 detects the nitrogen. The oxide concentration detection signal 55 is sent to the arithmetic and control unit 60.
Then, the arithmetic and control unit 60 compares it with the input signal 57 such as the reference nitrogen oxide concentration from the input setting unit 56.

As a result of the comparison, if the value of the nitrogen oxide concentration detection signal 55 is larger than the reference nitrogen oxide concentration, the arithmetic and control unit 60 sends the control signal 75 to the flow rate adjusting valve 73 (denitration agent supply valve). Is sent to inject the denitration agent in the denitration agent tank 65 (the denitration agent supply device) from the chemical injection nozzle 64 into the furnace to reduce nitrogen oxides.

At this time, the granular material 4 in the granular material supply device 47
When a small amount of 1 is dropped on the hopper section 36, the effect of reducing the nitrogen oxides by the denitration agent is increased by the powder particles 41 as a medium.

Alternatively, when the powder particles 41 are denitration agent particles, or when the powder particles 41 are mixed with denitration agent particles,
A control signal 59 is sent to the powder / granular material supply valve 46 (denitrifying agent supply valve) to open the powder / granular material supply valve 46 to drop a small amount of the powder / granular material 41 in the powder / granular material supply device 47 to the hopper section 36. To reduce nitrogen oxides.

Further, as described above, when the amount of nitrogen oxides generated is large, the temperature inside the furnace may rise. Therefore, by charging a large amount of cooled powder or granular material 41, the furnace The internal temperature may be lowered.

Contrary to the above, when the value of the nitrogen oxide concentration detection signal 55 is smaller than the reference nitrogen oxide concentration, it indicates that the combustion state is good, and therefore the control is particularly performed. No need. Alternatively, during this time, the hopper 36
It is also possible to adjust the level of the powder and granules 41 in step 1 to the reference level.

If the temperature measuring device 49 is provided, it is not necessary to provide the carbon monoxide concentration detector 50 and the nitrogen oxide concentration detector 51, but the carbon monoxide concentration detector 50 and the nitrogen oxide concentration detector 51 are required. Both may be provided, or only one of them may be provided.

The level of the powder / granular material 41 in the hopper section 36 is controlled by the powder / granular material level measuring device 48.
0 is monitored and controlled to eventually return to the reference level. Further, the primary combustion device 28 is a fluidized bed type, and the granular material 41
If the same is the same fluidized sand as that of the primary combustion device 28, the granular material 41 extracted from the extraction mechanism 42 may be sent to the primary combustion device 28 as indicated by an arrow 45.

The time during which the granular material level adjusting valve 44 and the granular material supply valve 46 are opened by the control signals 58 and 59 may be controlled by a timer or the like provided inside the arithmetic and control unit 60. good.

Then, the combustion gas generated by the combustion of the unreacted gas 37 and the solid unburned matter 67 in the complete combustion zone 61, next takes about 0.5 seconds, and then the drug reaction zone 62.
Pass through.

At this time, the chemical injection nozzle 64 provided at the boundary position between the lower complete combustion zone 61 and the upper chemical reaction zone 62 on the side wall of the secondary combustion device main body 34 is operated manually or as described above. By the control signal 75 from the arithmetic and control unit 60, the denitration agent in the denitration agent tank 65, the desulfurization agent in the desulfurization agent tank 66, and other chemicals 6
3 is injected and supplied toward the axial center position.

As a result, the swirling flow is used to promote the mixing of the chemicals 63 with the combustion gas that has finished combustion, and denitration and desulfurization of the combustion gas and decomposition of dioxins are performed in a non-catalytic state. In addition, as shown in the graph of FIG.
Are concentrated on the side wall portion of the secondary combustion device main body 34 along with the swirling flow, and are efficiently mixed with the combustion gas.

Here, for example, urea or the like is used as the denitration agent, and calcium carbonate or the like is used as the desulfurization agent. These may be jetted in the state of an aqueous solution or in the state of powder. To

The reason why the injection position of the chemical 63 is set to the boundary position between the complete combustion zone 61 and the chemical reaction zone 62 is that when the complete combustion zone 61 is provided, the unreacted gas 37 and the chemical 6
This is because there is a case where a harmful substance is generated by the reaction with 3. Moreover, when it is near the delivery side of the drug reaction zone 62,
This is because the mixing property of the chemical agent 63 with the combustion gas cannot be sufficiently ensured, and the temperature of the combustion gas at the injection position deviates from the optimum range of 850 to 950 ° C. for the denitration reaction and the like, so that the reaction is efficient. It will not be done.

FIG. 5 shows experimental data when urea water was injected as the denitration agent. As shown by the line a, the supply amount of urea water was reduced from about 200 ml / min to 0 ml / min, and then about When it was raised to 150 ml / min, the nitrogen oxide (NOx) generated was 20 pp as shown by the line B.
Since m increased to about 75 ppm and then decreased to 25 ppm, it was actually confirmed that the injection of the drug 63 from the boundary position between the complete combustion zone 61 and the drug reaction zone 62 was effective.

Then, the combustion gas that has been subjected to denitration and desulfurization in the chemical reaction zone 62 is then subjected to the secondary combustion device main body 34.
After being discharged from the combustion gas discharge port 35 at the upper end to the exhaust gas duct 68 and the heat being recovered by the heat recovery device 69, the dust collector 70
And is discharged to the atmosphere from the chimney 71 as exhaust gas 72.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0121]

As described above, according to the secondary combustion apparatus of the present invention, it is possible to obtain an excellent effect that a more complete combustion state can be obtained by attaching the secondary combustion apparatus to a general combustion apparatus.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of an embodiment of the present invention.

FIG. 2 is a view taken along the line II-II of FIG.

FIG. 3 is a graph showing the relationship between the radial position of the main body of the secondary combustion device and the flow rate of unreacted gas.

FIG. 4 is a graph showing the relationship between the radial position of the main body of the secondary combustion device and the concentration of solid unburned components and the concentration of chemicals.

FIG. 5 is a graph showing the relationship between the urea water injection amount and the NOx amount with the passage of time.

FIG. 6 is a graph showing the relationship between time and the concentration of carbon monoxide contained in the combustion gas discharged from the main body of the secondary combustion device.

FIG. 7 is a schematic side sectional view of a conventional example.

[Explanation of symbols]

 34 Main body of secondary combustion device 36 Hopper part 37 Unreacted gas 38 Gas inlet part 41 Granules 42 Extraction mechanism 44 Granule level control valve 46 Granules supply valve (denitration agent supply valve) 47 Granules supply device (Denitrification agent supply device) 49 Temperature measuring device 50 Carbon monoxide concentration detector 51 Nitrogen oxide concentration detector 53 Temperature measurement signal 54 Carbon monoxide concentration detection signal 55 Nitrogen oxide concentration detection signal 56 Input setting device 58, 59, 75 control signal 60 arithmetic control device 65 denitration agent tank (denitration agent supply device) 67 solid unburned component 73 flow rate adjustment valve (denitration agent supply valve)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F23N 5/24 107 F23N 5/24 107Z (72) Inventor Takeichi Kondo 3 chome, Toyosu, Koto-ku, Tokyo No. 1-15 Ishikawajima Harima Heavy Industries Ltd. Technical Research Institute (72) Inventor Hiroshi Aramaki 1-1-1, Toyosu Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Ltd. Tokyo No. 1 Factory (72) Inventor Masanobu Naito Tokyo Koto 2-1-1 Toyosu, Tokyo Ishikawajima Harima Heavy Industries Ltd. Tokyo No. 1 factory

Claims (5)

[Claims] 1. A secondary combustion apparatus main body having a cylindrical side wall is provided at a lower portion of a side wall thereof with a gas inlet portion into which an unreacted gas containing a solid unburned component can be introduced in a direction of an internal tangent line, and secondary combustion is performed. A secondary combustion device characterized in that powder particles are deposited in a hopper portion formed below the gas inlet portion of the apparatus main body to a height at which it can be blown up by unreacted gas introduced from the gas inlet portion. . 2. The secondary combustion device according to claim 1, wherein the gas inlet portion is arranged so as to be inclined downward so as to face the powder or granular material accumulated in the hopper portion. 3. A secondary combustion device main body is provided with a powder / granule supply device equipped with a powder / granule supply valve, and a lower end of a hopper is equipped with a powder / granule level control valve so that the powder / granule can be taken out of the system. In addition to the automatic discharge mechanism, a temperature measuring device is installed in the main body of the secondary combustion device, and the temperature measuring signal measured by the temperature measuring device is compared with the reference temperature input to the input setting device, and the particulate material supply valve The secondary combustion apparatus according to claim 1 or 2, further comprising an arithmetic control device for sending a control signal for injecting the powder or granular material or a control signal for ejecting the powder or granular material out of the system to the powder or granular material level adjusting valve. . 4. The secondary combustion apparatus main body is provided with a powdery or granular material supply device equipped with a powdery or granular material supply valve, and a carbon monoxide concentration detector is provided at a gas outlet portion of the secondary combustion apparatus main body, so An arithmetic and control unit that compares the carbon monoxide concentration detection signal detected by the carbon concentration detector with the reference carbon monoxide concentration input to the input setting device, and sends a control signal for charging the granular material supply valve with the granular material. The secondary combustion device according to claim 1, wherein the secondary combustion device is provided. 5. A denitrification agent supply device equipped with a denitration agent supply valve is attached to the main body of the secondary combustion device, and a nitrogen oxide concentration detector is provided at the gas outlet portion of the main body of the secondary combustion device to obtain the nitrogen oxide concentration. A control device for comparing the nitrogen oxide concentration detection signal detected by the detector with the reference nitrogen oxide concentration input to the input setting device and sending a control signal for injecting the denitration agent into the denitration agent supply valve is provided. Item 2. The secondary combustion device according to any one of items 1 to 4.