JP2002276919A - Refuse incinerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce operation cost by forming a structure capable of suppressing a consumption amount of a hydrocarbon fuel. SOLUTION: A refuse incinerator is constituted to completely burn an unburned material or an incompletely burned material by supplying the hydrocarbon fuel from a hydrocarbon fuel supply unit 9 to form a reducing atmosphere 4B and supplying a secondary combustion air above the reducing atmosphere 4B above a primary combustion zone 4A for mainly burning a refuse by a primary combustion air. The incinerator further comprises a laser detector 10 for irradiating the reducing atmosphere 4B with a laser beam through a measuring window 12 formed at a furnace body 2 to detect a concentration of at least one composition of respective types of compositions of the atmosphere 4B real time, and a control means 17 for controlling the supply unit 9 based on the detected result of the meter 10 so that the concentration of the detected composition becomes a target concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a reducing atmosphere by supplying a hydrocarbon-based fuel from a hydrocarbon-based fuel supply section above a primary combustion zone in which refuse is primarily combusted by primary combustion air. A refuse incinerator configured to supply secondary combustion air above the reducing atmosphere to completely burn unburned or incompletely burned materials, and a primary combustion zone for mainly burning refuse with primary combustion air. A reducing atmosphere forming means for forming a reducing atmosphere is provided above, and secondary combustion air is supplied above the reducing atmosphere to completely burn unburned substances or incompletely burned substances. The atmosphere forming means extracts the gas generated by the post-combustion of the main combusted refuse from the post-combustion zone to the outside of the furnace main body, mixes it with the hydrocarbon-based fuel, burns it, and supplies it above the primary combustion zone. On garbage incinerator that is configured to so that.

[0002]

2. Description of the Related Art This type of refuse incinerator uses nitrogen oxides (NO
_X ) ・ Developed to reduce the emission of air pollutants such as dioxins, and operates as follows.

That is, in the case of the former type of waste incinerator of the two types described above, hydrocarbon fuel (hereinafter, referred to as "natural gas") is provided above the primary combustion zone. By blowing, a reducing atmosphere (reburning zone) is formed.

[0004] Thus to remove NO _X, and residual hydrocarbons after reduction with natural gas, is completely burned by the secondary combustion air and a hydrocarbon · CO generated in the combustion chamber.

In the case of the latter refuse incinerator, the exhaust gas generated by the post-combustion of the refuse in the main combustion is extracted from the post-combustion zone to the outside of the furnace body, mixed with natural gas and burned, and is blown above the primary combustion zone. Forms a reducing atmosphere.

[0006] Thus to remove NO _X, and residual hydrocarbons after reduction with natural gas, is completely burned by the secondary combustion air and a hydrocarbon · CO generated in the combustion chamber.

[0007] As described above for operating the waste incinerator, as compared with the case of not using natural gas, 60% maximum emissions NO _X · CO respectively, can be suppressed by reduction rate of 50%.

Conventionally, the above-mentioned refuse incinerator blows a large amount of natural gas or the like into the upper part of the primary combustion zone or reduces the reducing atmosphere so that the reducing atmosphere can be more reliably formed. It was structured to be burned.

[0009]

According to the above conventional structure, a large amount of natural gas or the like is blown above the primary combustion zone or burned by the reducing atmosphere forming means. However, natural gas consumption has increased and operating costs have increased.

An object of the present invention is to reduce the operating cost by adopting a structure capable of suppressing the consumption of hydrocarbon fuel.

[0011]

The constitution, operation and effect of the invention according to claim 1 are as follows.

[Structure] A hydrocarbon-based fuel is supplied from a hydrocarbon-based fuel supply unit above a primary combustion zone in which refuse is primarily combusted by primary combustion air to form a reducing atmosphere.
A refuse incinerator configured to supply secondary combustion air above the reducing atmosphere to completely burn unburned or incompletely burned materials, wherein the laser detector is provided through a measurement window formed in the furnace body. By irradiating the reducing atmosphere with a laser beam, the concentration of at least one of the various compositions in the reducing atmosphere is configured to be detected in real time, and the concentration of the detected composition is targeted. Control means is provided for controlling the hydrocarbon-based fuel supply unit based on the detection result of the laser detector so that the concentration becomes the concentration.

[Operation] [A] A predetermined amount of hydrocarbon fuel is supplied from a hydrocarbon fuel supply section above the primary combustion zone to form a reducing atmosphere.

[B] Then, the reducing atmosphere is irradiated with laser light by a laser detector through a measuring window formed in the furnace main body, so that various compositions (NO _x ·
CO, O ₂ , CH _4, etc.) and the concentration of at least one composition (for example, O ₂ ).

For example, detection is performed as follows.

Structure: A laser beam generated from a semiconductor laser transmitter is guided to a laser projector through an optical fiber, irradiated to the reducing atmosphere, and the residual laser beam intensity is detected by a laser detector.

Principle (Spectral Absorption Method) Each composition in a gas has a specific absorption wavelength with respect to an infrared laser. As the laser light passes through the measurement gas body, certain compositions in the gas absorb the laser light of a particular wavelength and are proportional to the amount of absorbed laser light and its gas concentration. By detecting the amount of absorbed laser light of a specific wavelength, the concentration of the specific composition in the gas can be converted.

As described above, the concentration of the composition is detected in real time by irradiating the reducing atmosphere with laser light, and the control means controls the hydrocarbon-based fuel supply section based on the detection result. Then, the supply amount of the hydrocarbon-based fuel to the reducing atmosphere is changed and adjusted, and the detected concentration of the composition is set to the target concentration.

As an example, the O ₂ concentration is set to 1%.
Next, the reason will be described.

A hydrocarbon fuel, for example, methane (CH ₄ )
Consumes O ₂ by the next combustion reaction, resulting in CO ₂ , H ₂ O
Generate

2CH ₄ +4 O ₂ → 2 CO ₂ + 4H ₂ O Therefore, if the supply amount of the hydrocarbon-based fuel (in this case, methane) is increased, the O _{2 in the} reducing atmosphere decreases, and conversely, the supply amount can be reduced. O ₂ increases.

A correlation has been found experimentally between the O ₂ concentration in the reducing atmosphere and the amount of NO _x generated (FIG. 6). According to FIG. 6, if the O ₂ concentration in the reducing atmosphere is 1% or less, NO _X
It can be seen that can be suppressed.

When a plurality of hydrocarbon fuel supply ports are provided, the distribution ratio of the hydrocarbon fuel to each supply port can be set by the control means based on the detection result of the laser detector. This makes it easier to set the concentration of the detected composition to a target concentration.

[C] By the above operation [B], the required amount of the hydrocarbon-based fuel can be blown above the primary combustion zone, and unnecessary consumption of the hydrocarbon-based fuel can be avoided.

[4] Since the concentration of the composition is detected by irradiating the reducing atmosphere with laser light by a laser detector through a measuring window formed in the furnace main body, for example, the gas in the reducing atmosphere is used. Unlike the means for taking out the outside of the furnace body and detecting the concentration, the concentration can be detected in real time.

As a result, when the combustion state in the furnace changes, the supply amount of the hydrocarbon-based fuel can be changed and adjusted instantaneously according to the change.

[Effect] Therefore, the above operations [A],
[B] and [c] can avoid wasteful consumption of hydrocarbon-based fuel and can reduce the operating cost, and the above operations [a], [b] and [d] can reduce Atmosphere can be formed stably, and nitrogen oxide (N
O _X) could be more easily suppressed emission of air pollutants, and the like.

The structure, operation and effect of the invention according to claim 2 are as follows.

[Structure] A reducing atmosphere forming means for forming a reducing atmosphere is provided above a primary combustion zone for mainly burning refuse with primary combustion air, and secondary combustion air is supplied above the reducing atmosphere. The unburned material or the incompletely burned material is configured to be completely burned, and the reducing atmosphere forming means extracts a gas generated by a post-combustion of the main-burned refuse from the post-combustion zone to the outside of the furnace main body. A refuse incinerator configured to be mixed with fuel and burned, and supplied above the primary combustion zone, wherein a laser beam is applied to the reducing atmosphere by a laser detector through a measurement window formed in the furnace body. By irradiating the composition, the concentration of at least one of the various compositions in the reducing atmosphere is detected in real time, and the concentration of the detected composition is adjusted to the target concentration. So that, on the basis of the detection result of the laser detection meter is provided with a control means for controlling the reducing atmosphere forming means.

[Effect] [E] Exhaust gas generated by post-combustion of the main-burned refuse is extracted from the post-combustion zone to the outside of the furnace main body. Then, the exhaust gas is mixed with the hydrocarbon-based fuel and burned, and supplied to above the primary combustion zone (this gas is referred to as “reducing gas”) to form a reducing atmosphere. [F] Then, the reducing atmosphere is irradiated with laser light by a laser detector through a measurement window formed in the furnace main body, so that various compositions of the reducing atmosphere (NO _X , CO, O ₂₎
- at least one composition out of CH _4, etc.) (e.g., O
₂ ) Detect the concentration.

For example, detection is performed as follows.

Structure: A laser beam generated from a semiconductor laser transmitter is guided to a laser projector via an optical fiber, irradiated to the reducing atmosphere, and the residual laser beam intensity is detected by a laser detector.

Principle (Spectral Absorption Method) Each composition in the gas has a specific absorption wavelength for an infrared laser. As the laser light passes through the measurement gas body, certain compositions in the gas absorb the laser light of a particular wavelength and are proportional to the amount of absorbed laser light and its gas concentration. By detecting the amount of absorbed laser light of a specific wavelength, the concentration of the specific composition in the gas can be converted.

As described above, the concentration of the composition is detected in real time by irradiating the reducing atmosphere with the laser beam, and the control means controls the hydrocarbon fuel supply section based on the detection result. Then, the supply amount of the hydrocarbon-based fuel to the reducing atmosphere is changed and adjusted, and the detected concentration of the composition is set to the target concentration.

As an example, the O ₂ concentration is set to 1%.
Next, the reason will be described.

Hydrocarbon fuel, for example, methane (CH ₄ )
Consumes O ₂ by the next combustion reaction, resulting in CO ₂ , H ₂ O
Generate

2CH ₄ +4 O ₂ → 2 CO ₂ + 4H ₂ O Therefore, if the supply amount of the hydrocarbon-based fuel (in this case, methane) is increased, the O _{2 in the} reducing atmosphere decreases, and conversely, the supply amount can be reduced. O ₂ increases.

A correlation has been found experimentally between the O ₂ concentration in the reducing atmosphere and the amount of NO _x generated (FIG. 6). According to FIG. 6, if the O ₂ concentration in the reducing atmosphere is 1% or less, NO _X
It can be seen that can be suppressed.

When a plurality of reducing gas supply ports are provided in the furnace body, the distribution ratio of the reducing gas to each supply port can be set by the control means based on the detection result of the laser detector. This makes it easier to set the concentration of the detected composition to a target concentration.

[G] By the above-mentioned action [f], the required amount of the hydrocarbon fuel can be combusted by the reducing atmosphere forming means, and wasteful consumption of the hydrocarbon fuel can be avoided.

[H] The concentration of the composition is detected by irradiating the reducing atmosphere with laser light with a laser detector through a measuring window formed in the furnace body. There is an advantage that the concentration can be detected in real time, unlike means for detecting the concentration by taking it out of the main body.

As a result, when the combustion state in the furnace changes, the supply amount of the reducing gas can be instantaneously changed and adjusted according to the change.

[Effect] Therefore, the above operation [e],
By using [f] and [g], it is possible to avoid wasteful consumption of hydrocarbon-based fuel and to reduce operating costs. Atmosphere can be formed stably, and nitrogen oxide (N
O _X) could be more easily suppressed emission of air pollutants, and the like.

The structure, operation and effect of the invention according to claim 3 are as follows.

[Structure] In the structure of the invention according to claim 1 or 2, the at least one composition is oxygen.

[Operation] In addition to the same operation as the operation according to the first or second aspect, the following operation can be obtained.

By irradiating the reducing atmosphere with a laser beam, the oxygen concentration (hereinafter referred to as “O ₂ concentration”)
Detects a designated), based on the detection result, controls the hydrocarbon-based fuel supply unit in the control unit, O ₂ concentration and feed rate of the hydrocarbon-based fuel to change adjusted and the detection for reducing atmosphere Is set to the target concentration.

As an example, the O ₂ concentration is set to 1%.
The reason is as described in the operation of claims 1 and 2.

[Effects] Therefore, in addition to the effects similar to the effects of the structure of claim 1 or 2,
The NO _X can now suppressed.

[0050]

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

[First Embodiment] FIGS. 1 and 2 show a refuse incinerator. This refuse incinerator is provided with a stoker 3 for burning refuse from a hopper 1 in a furnace body 2 and a primary combustion air supply device 5 for supplying air to a primary combustion zone 4A.
A hydrocarbon-based fuel (hereinafter, referred to as “natural gas”) is blown from the natural gas supply port 19 above the primary combustion zone 4A to form a reducing atmosphere 4B (hereinafter, referred to as “reburning zone 4B”). Natural gas supply unit 9 (corresponding to a hydrocarbon fuel supply unit) and reburning zone 4
A secondary combustion air supply device 6 for supplying secondary combustion air to the secondary combustion zone 4C above B to completely burn unburned or incompletely burned materials, and an ash discharge port 7 for discharging ash are provided. It is configured.

The stoker 3 includes a drying stoker 3A, a combustion stoker 3B, and a post-combustion stoker 3C. The stoker 3 is provided with a primary air duct 8 through which primary combustion air from a blower 30 of the primary combustion air supply device 5 passes. 3B, 3C
Is connected to the lower side of the.

The refuse introduced into the hopper 1 includes a dry stoker 3A, a burning stoker 3B, and a post-burning stoker 3C.
And the primary combustion by the primary combustion air.

In the drying stoker 3A, refuse is mainly dried by high-temperature combustion gas generated by the combustion in the subsequent combustion stoker 3B and the post-combustion stoker 3C, and partial combustion starts. The gas generated from the dust on the drying stoker 3A is, for example, water vapor generated by evaporation of water, hydrocarbon gas generated by dry distillation, and CO generated by incomplete combustion.

In the combustion stoker 3B, dust is mainly burned by the primary combustion air. Primary combustion air supplied to the combustion stoker 3B is an amount necessary and sufficient for combustion of waste, the gas generated from the dust 2 on combustion stoker 3B includes a high concentration of NO _x.

The post-combustion stoker 3C aims to burn off the unburned portion in the incineration ash. About 15 to 19% of oxygen remains in the combustion gas in the post-combustion zone 11 above the post-combustion stoker 3C, and an oxidizing atmosphere is formed.

Since this combustion gas has a relatively low temperature, and furthermore, the nitrogen component in the garbage is almost eliminated.
NO _x occurring in the post-combustion stoker 3C are reduced. Further, HCl, which is a corrosive substance, is hardly contained.

As shown in FIGS. 2 and 3, a measurement window 12 is formed in the furnace main body portion on the reburning zone 4B side, and the laser beam is irradiated on the reburning zone 4B by the laser detector 10 through the measurement window 12. By doing so, various compositions (NO _X · CO · O ₂ CH _{4) in the} reburning zone 4B
The control device 17 controls the natural gas supply unit 9 based on the detection result of the laser detector 10 so that the detected concentration of the composition becomes the target concentration. Means).

As shown in FIG. 3, the measurement window 12 is formed by forming two openings on the side wall 2A of the furnace main body 2 on the laser transmission side and the reception side so that the laser beam can be directly transmitted. Irradiation into the furnace.

In this structure, it is conceivable to use a purge gas in order to prevent contamination of the lenses on the laser transmitting side and the receiving side.

As shown in FIGS. 2 and 3, the laser detector 10 includes a detection main body 20 having a laser light source and a measurement window 1.
2 is connected to the optical fiber cable 15 via the signal processor 21 and is connected to the control device 17 so that the control device 17 can execute various calculations. is there.

The laser detector 10 detects the concentration of the composition as follows.

In a state where the natural gas is supplied from the natural gas supply unit 9 and the reburning zone 4B is formed, the laser transmitter 31 emits a laser beam having a constant intensity while scanning the wavelength. The laser beam is adjusted to a constant beam diameter by the laser projection device 14 and then directly irradiates the reburning zone 4B, and at the same time as passing through the furnace gas,
Laser light of a specific wavelength is absorbed by a certain composition in the gas.

Then, the intensity of the remaining laser beam is measured by a laser detector 14 ′ installed on the opposite side of the laser projection device 14, and the concentration of the composition corresponding to the wavelength of the specific absorption is measured by the signal processor 21. Ask for.

As described above, since the concentration of various compositions (NO _X , CO, O ₂ , CH _4, etc.) is detected by the laser detector 10, the concentration can be detected in real time.

When the concentration of the composition in the reburning zone 4B is detected, the natural gas supply unit 9 is controlled to change and adjust the supply amount of the natural gas to the reburning zone 4B. Set the concentration of the composition to the target concentration.

In the above case, the various compositions (NO _X ·
CO · O ₂ · CH one composition out of _4, etc.) (e.g., O
₂ ) detecting the concentration of the composition and controlling the natural gas supply unit 9 with the control device 17 so that the detected concentration of the composition becomes the target concentration (for example, so that the O ₂ concentration becomes 1%); , to detect the concentration of _{NO X · CO · O 2 ·} CH several compositions, such as _4, so that the concentration of the composition the detected reaches a target concentration, the natural gas supply unit 9 in the control unit 17 Means for controlling can be taken.

[Second Embodiment] The refuse incinerator of the present embodiment is different from the refuse incinerator of the first embodiment in the primary combustion zone 4A.
The means for forming the reburning zone 4B above is different (other structures are the same).

That is, as shown in FIG. 4 and FIG. 5, the reburning zone forming means 18 (corresponding to the reducing atmosphere forming means) converts the exhaust gas generated by the post-combustion of the main-burned refuse above the post-combustion stoker 3C. The primary combustion zone 4A is sucked from the post-combustion zone 11 (as described above, about 15 to 19% of oxygen remains in the combustion gas and has an oxidizing atmosphere), mixed with natural gas and burned.
Is supplied from the supply port 20 (this gas is referred to as “reducing gas”).

With the above structure, the laser detector 10 irradiates the reburning zone 4B with the laser beam through the measurement window 12 in a state where the reburning gas is supplied from the reducing gas supply unit 18 and the reburning zone 4B is formed. And various compositions in the reburning zone 4B (NO _X · CO · O
₂ CH _4, etc.) (the principle of detection is as described in the first embodiment).

The control device 17 controls the reducing gas supply means 1
8, the supply amount of the reducing gas to the reburning zone 4B is changed and adjusted, and the concentration of the detected composition in the reburning zone 4B is set to the target concentration.

In the above case, similarly to the case of the first embodiment, the various compositions (NO _X , CO, O ₂ , CH ₄₎
And the like, and the concentration of one composition (for example, O ₂ ) is detected, and the reducing gas supply is performed so that the concentration of the detected composition becomes a target concentration (for example, the O ₂ concentration becomes 1%). means for controlling the means 18 in the controller 17 or, NO _X · C
Means for detecting the concentration of several kinds of compositions such as O.O ₂ CH ₄ and controlling the reducing gas supply means 18 with the control device 17 so that the detected concentration of each composition becomes the target concentration is adopted. be able to.

[Another Embodiment] The natural gas supply port 19
Or a plurality of supply ports 20 for reducing gas.

In this case, the distribution ratio of the natural gas (reducing gas) to each supply port 19 (20) is set by the control device 17 based on the detection result of the laser detector 10, and the concentration of the detected composition is determined. Can be set to a target density.

The number of the measurement windows 12 is not limited to the number in the above embodiment, and a plurality of measurement windows may be provided, for example.

The hydrocarbon fuel is not limited to natural gas, but may be another hydrocarbon fuel.

Instead of supplying the hydrocarbon-based fuel alone, a method may be used in which the hydrocarbon-based fuel supply unit is mixed with a recirculated gas (to circulate exhaust gas downstream of the incinerator) and supplied. .

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a combustion furnace.

FIG. 2 is a front view of a combustion furnace.

FIG. 3 shows a heat-resistant probe.

FIG. 4 is a diagram showing another embodiment.

FIG. 5 is a diagram showing another embodiment.

FIG. 6: Reduction atmosphere NO _X generation amount and reduction atmosphere O ₂
Diagram showing relationship with concentration

[Explanation of symbols]

 2 Furnace main body 4A Primary combustion zone 4B Reducing atmosphere 6 Secondary combustion air supply device 9 Hydrocarbon fuel supply unit 10 Laser detector 12 Measurement window 17 Control means 18 Reducing atmosphere forming means

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shizuo Kataoka 2-33, Kinrakuji-cho, Amagasaki-shi, Hyogo F-term in Takuma Co., Ltd. (Reference) 3K062 AA02 AB01 AC01 AC19 BA02 CA06 CB06 CB08 DA21 DA23 DB13 3K078 BA03 BA21 BA22 BA26 CA03 CA09 CA10 CA12

Claims (3)

[Claims] 1. A reducing atmosphere is formed by supplying a hydrocarbon-based fuel from a hydrocarbon-based fuel supply unit above a primary combustion zone in which refuse is primarily combusted by primary combustion air, and a reducing atmosphere is formed above the reducing atmosphere. A refuse incinerator configured to completely burn unburned or incompletely combusted products by supplying secondary combustion air, wherein a laser is supplied to the reducing atmosphere by a laser detector through a measurement window formed in the furnace body. By irradiating light, the concentration of at least one composition among the various compositions in the reducing atmosphere is configured to be detected in real time, so that the concentration of the detected composition becomes a target concentration, A refuse incinerator provided with control means for controlling the hydrocarbon-based fuel supply section based on a detection result of a laser detector. 2. A reducing atmosphere forming means for forming a reducing atmosphere above a primary combustion zone in which refuse is mainly combusted by primary combustion air, and a secondary combustion air is supplied above the reducing atmosphere. The reducing atmosphere forming means is configured to completely burn combustibles or incompletely combusted products, and the reducing atmosphere forming means extracts a gas generated by post-combustion of the main-burned refuse from the post-combustion zone to the outside of the furnace main body, and generates A refuse incinerator configured to mix and burn with the primary combustion zone and supply the light to the reducing atmosphere with a laser detector through a measurement window formed in the furnace body. By irradiating, the concentration of at least one composition among the various compositions in the reducing atmosphere is configured to be detected in real time, and the concentration of the detected composition becomes the target concentration. As such, based on the detection result of the laser detection meter, the reducing waste incinerator that is a control means is provided for controlling the atmosphere creation means. 3. The incinerator according to claim 1, wherein the at least one composition is oxygen.