JP2733201B2 - Garbage incineration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary combustion zone in which a flue is formed in a space above a primary combustion zone having a stoker type incineration zone for incinerating garbage, and is provided downstream of the flue. A waste incinerator equipped with a waste heat boiler that recovers heat from exhaust gas,
Combustion superheater that superheats the steam generated from the waste heat boiler, and a power generation device including a steam turbine that generates power using superheated steam by the combustion superheater, the combustion exhaust gas from the combustion superheater, The present invention relates to a refuse incineration device provided with a secondary combustion gas supply passage that leads the oxygen concentration to the secondary combustion region in a state where the oxygen concentration is low.

[0002]

2. Description of the Related Art As shown in FIG. 4, this type of refuse incinerator prevents a decrease in gas temperature in a secondary combustion zone, promotes complete combustion, and reduces the amount of generated carbon monoxide and carbon monoxide. To suppress the generation of positively correlated dioxins, the flue 4
A secondary combustion gas supply mechanism 15 for injecting secondary combustion gas is provided upstream of the incineration zone 3 and upstream of the incineration zone 3. The high-temperature combustion exhaust gas from the combustion type superheater 8 is used to reduce the oxygen concentration. The secondary combustion gas supply path 14 that supplies the secondary combustion gas supply mechanism 15 to the secondary combustion gas supply mechanism 15 so as to guide the secondary combustion gas to the secondary combustion area in a lowered state.
Was provided.

[0003]

However, in the above-mentioned conventional refuse incinerator, the secondary combustion gas supply mechanism 15 is provided upstream of the flue 4 and upstream of the incineration zone 3. In addition, the combustion gas injected from such a position has a disadvantage that the combustible gas generated in the drying zone A constituting the upstream side of the incineration zone 3 cannot be effectively burned. .

That is, according to the visualization experiment of the flow caused by the water flow, the combustible gas generated in the drying zone A rises as it is, flows in a layer along the upper wall surface 4b to the flue 4, and is incinerated in the incineration zone 3. It has been found that the fuel gas is not uniformly mixed with the combustion gas flow in the combustion zone B constituting the downstream side of the fuel cell and is guided to the flue 4 in a layer.
5, the combustion gas injected at a higher speed penetrates such a flammable gas flow and reaches the space above the combustion zone B, and thus does not contribute to combustion effectively. .

[0005] Further, when the oxygen concentration distribution at the inlet cross section of the flue 4 is calculated, as shown in Fig. 2 (a), a large concentration gradient of about 8% on the drying zone A side and about 15% on the combustion zone B side. When flowing into the flue while maintaining such a concentration gradient, incomplete combustion occurs due to lack of oxygen in the drying zone A of the flue 4 and, on the contrary, nitrogen oxidation occurs in the combustion zone B of the flue 4. In order to avoid such a problem, it is necessary to further provide an expensive exhaust gas treatment device and the like, and there has been a problem that the equipment cost is eventually increased.

On the other hand, if the supply gas pressure from the conventional secondary combustion gas supply mechanism 15 is reduced, the inconvenience of penetrating the combustible gas flow is eliminated, but it is determined according to the flow rate of the combustible gas flowing through the drying zone. Further, an appropriate amount of secondary air cannot always be supplied, and the generation of nitrogen oxides on the combustion zone B side of the flue 4 cannot be reduced.

[0007] The object of the present invention, in view of the problems described above,
In the point of providing a refuse incinerator capable of uniformly diffusing a combustion gas without causing a temperature drop in a secondary combustion region to promote complete combustion and simultaneously reduce generation of nitrogen oxides. is there.

[0008]

In order to achieve this object, a refuse incinerator according to the present invention is characterized in that the refuse incinerator is arranged upstream of the flue and downstream of the incineration zone, downstream of the incineration zone. And a secondary combustion gas supply mechanism for injecting secondary combustion gas from upstream to upstream is provided, and a secondary combustion gas supply path is connected to the secondary combustion gas supply mechanism.

In the above configuration, a gas sensor for detecting the concentration of oxygen contained in the exhaust gas from the refuse incinerator is provided.
A secondary combustion gas supply amount adjusting mechanism for adjusting an injection amount of the secondary combustion gas from the secondary combustion gas supply mechanism is provided so that the oxygen concentration detected by the gas sensor is maintained at a predetermined target value. Is preferred.

In the above configuration, a temperature sensor for detecting the temperature of the exhaust gas from the refuse incinerator is provided, and the temperature of the exhaust gas detected by the temperature sensor is maintained at a predetermined target value from the secondary combustion gas supply mechanism. It is preferable to provide a secondary combustion gas supply amount adjustment mechanism for adjusting the secondary combustion gas injection amount.

[0011]

The secondary combustion gas supply mechanism is configured to inject secondary combustion gas upstream of the flue and downstream of the incineration zone from downstream to upstream of the incineration zone. Since the secondary combustion gas is injected from the secondary combustion gas supply mechanism, the combustion gas with a high oxygen concentration flowing into the combustion zone side of the flue (downstream of the incineration treatment zone) is entrained. As a result, the uniform diffusion of the combustion gas in the flue is promoted as a result of the flow toward the unburned gas having a low oxygen concentration flowing into the drying zone of the flue (upstream of the incineration zone). At this time, the combustion gas generated in the primary combustion region already contains an amount of oxygen required for the secondary combustion, and when supplying normal air as the secondary combustion gas in the secondary combustion region, Since there is a possibility that the amount of nitrogen oxides may increase due to excessive oxygen, the high-temperature combustion exhaust gas from the combustion type superheater is supplied at a low oxygen concentration to generate nitrogen oxides due to excess oxygen supply. And promotes secondary combustion by maintaining the combustion temperature in the secondary combustion region at a high temperature.

In general, for complete combustion of carbon monoxide, a sufficient amount of oxygen, a burning time and a burning temperature are required.
It is known that it is sufficient if the residual oxygen concentration in the exhaust gas is about 8%. Therefore, a gas sensor for detecting the concentration of oxygen contained in the exhaust gas of the refuse incinerator is provided, and the oxygen concentration detected by the gas sensor is adjusted to a predetermined target value, for example, 8 by the secondary combustion gas supply amount adjusting mechanism.
% By adjusting the injection amount of the secondary combustion gas from the secondary combustion gas supply mechanism so as to maintain the combustion condition in the secondary combustion region.

Further, focusing on the combustion temperature, in order to promote complete combustion of carbon monoxide in the secondary combustion region, the region must be heated to at least about 650 which is the combustion temperature of carbon monoxide.
It must be maintained above ℃. Therefore, a temperature sensor for detecting the exhaust gas temperature of the refuse incinerator is provided, and the secondary combustion gas supply amount adjusting mechanism is configured to maintain the exhaust gas temperature detected by the temperature sensor at a predetermined target value, for example, 850 ° C. or higher. By adjusting the injection amount of the secondary combustion gas from the secondary combustion gas supply mechanism, the combustion conditions in the secondary combustion region can be kept good.

[0014]

According to the present invention, in the secondary combustion region, the combustion gas is uniformly diffused without causing a temperature decrease, thereby promoting complete combustion and simultaneously reducing the generation of nitrogen oxides. It has become possible to provide a garbage incinerator capable of performing the above.

[0015]

Embodiments will be described below. As shown in FIG. 1, the refuse incineration apparatus includes a flue 4 in a space above a primary combustion region R1 provided with a stoker-type incineration treatment zone 3 for incinerating refuse.
To form a secondary combustion region R2, a refuse incinerator 1 provided with a waste heat boiler 7 for recovering heat from exhaust gas on the downstream side of the flue 4 and a combustion for heating steam generated from the waste heat boiler 7 It comprises a superheater 8 and a power generation device 9 having a steam turbine 9a that generates power using superheated steam generated by the combustion superheater 8.

The refuse incinerator 1 will be described in detail. The refuse introduced into the hopper 2 is introduced into the furnace by a hydraulically driven pusher 2a, and is primarily burned in the incineration treatment zone 3. The incineration zone 3 is provided with a stoker mechanism for transporting dust by reciprocating motion of the grate 3a, and a drying zone A for drying the dust in order from the upstream side, and a combustion zone B for burning the dried dust. After the burned refuse is completely incinerated, the combustion zone C is cascade-installed in a step-like manner, and wind boxes 6c, 6d, 6e are provided below each processing zone to provide a blower 6a,
A primary combustion air supply mechanism 6 for supplying air for primary combustion via an air passage 6b is provided. The flue 4 has a rectangular cross section in the space above the drying zone A and above the combustion zone B, and a combustion containing a combustible gas (reducing gas) generated in the drying zone A and NOx generated in the combustion zone B. NOx by mixing gas
And a secondary combustion region R2 in which carbon monoxide is completely burned.

Exhaust gas heat-exchanged in the waste heat boiler 7 is exhausted from a chimney 11 after harmful substances and soot and dust are removed by an exhaust gas treatment device 10 such as a bag filter or a smoke washer.

The power generator 9 comprises a steam turbine 9a and a generator 9b driven by the steam turbine 9a. The steam at about 310.degree.
The heat is supplied to the combustion type superheater 8 through the heater, the temperature is increased to about 500 ° C. by the heat of combustion by the superheating burner 8a, and then supplied to the steam turbine 9a through the steam supply path 13. That is, since corrosive gas such as hydrogen chloride is generated in the exhaust gas from the incinerator 1, about 31%
Since it is not possible to overheat to 0 ° C. or more, an external superheater is provided to overheat and enhance the power generation efficiency.

The combustion is performed in a state where the amount of air supplied to the superheating burner 8a is increased from the required amount of air, and high-temperature combustion exhaust gas having an oxygen content of about 3.5% and about 400 ° C. is supplied to the secondary combustion gas supply. It is configured to be guided to the secondary combustion region R2 via the path 14.

More specifically, on the wall 4a on the upstream side of the flue 4 and on the downstream side of the incineration zone 3, the downstream side (combustion zone B side) of the incineration zone 3 upstream (drying). Obi A
Side), more specifically, a secondary combustion gas supply mechanism 15 including a plurality of nozzles 15a for injecting secondary combustion gas is provided toward a step formed by the drying zone A and the combustion zone B, The secondary combustion gas supply path 14 is connected to the secondary combustion gas supply mechanism 15 via a damper mechanism 16a.

A gas sensor S1 for detecting the concentration of oxygen contained in the exhaust gas from the refuse incinerator 1 is provided on the downstream side of the exhaust gas treatment device 10, and the oxygen concentration detected by the gas sensor S1 is about 8 which is a target value. % Of the secondary combustion gas supplied from the secondary combustion gas supply mechanism 15 so as to be maintained at or above the secondary combustion gas supply amount adjustment mechanism 16.
Is provided.

That is, the secondary combustion gas supply amount adjusting mechanism 1
Reference numeral 6 includes the damper mechanism 16a and a control device 16b which receives a signal from the gas sensor S1 and adjusts the opening of the damper mechanism 16a.

Another embodiment will be described below. As shown in FIG. 3, a temperature sensor S2 for detecting exhaust gas temperature is provided in the secondary combustion region R2 so that the exhaust gas temperature detected by the temperature sensor S2 is set to a predetermined target value, for example, 800 to 950.
℃, the secondary combustion gas supply mechanism 15
A secondary combustion gas supply amount adjusting mechanism 16 for adjusting the injection amount of the secondary combustion gas from the engine may be provided. That is, the secondary combustion gas supply amount adjustment mechanism 16 includes the damper mechanism 16a and a control device 16c that receives a signal from the temperature sensor S2 and adjusts the opening of the damper mechanism 16a.
When the detected exhaust gas temperature is lower than the target value, the opening degree of the damper mechanism 16a is adjusted to a small value to prevent the temperature from being lowered by cooling due to excessive supply, and when the detected exhaust gas temperature is higher than the target value,
The degree of opening of the damper mechanism 16a is largely adjusted to promote secondary combustion. Note that the target value is an example, and is not limited to this value.

Further, the secondary combustion gas supply amount adjusting mechanism 16
May be provided with the above-mentioned gas sensor S1 and temperature sensor S2, and the opening degree of the damper mechanism 16a is adjusted by the detection input of both sensors.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a municipal garbage incinerator according to the present invention.

FIG. 2 is an explanatory diagram of an experimental result.

FIG. 3 is an explanatory view of an urban refuse incineration apparatus showing another embodiment.

FIG. 4 is an explanatory view of a municipal garbage incinerator showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 incinerator 3 incineration zone 4 flue 7 waste heat boiler 8 combustion superheater 9 power generation device 9a steam turbine 14 secondary combustion gas supply path 15 secondary combustion gas supply mechanism

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Satoshi Kuroishi 1-1-1 Hama, Amagasaki-shi, Hyogo Pref.

Claims (3)

(57) [Claims] A flue (4) is formed in a space above a primary combustion area provided with a stoker-type incineration treatment zone (3) for incinerating garbage to form a secondary combustion area. A refuse incinerator (1) provided with a waste heat boiler (7) for recovering heat from exhaust gas on the downstream side; a combustion type superheater (8) for heating steam generated from the waste heat boiler (7); Steam turbine (9a) that generates power using superheated steam by a superheater (8)
A secondary combustion gas supply passage (14) for guiding the combustion exhaust gas from the combustion type superheater (8) to the secondary combustion region in a state where the oxygen concentration is low. A refuse incineration apparatus provided, wherein the refuse incineration device is provided on the upstream side of the flue (4) and on the downstream side of the incineration zone (3) from the downstream side of the incineration zone (3) to the upstream side. A secondary combustion gas supply mechanism (15) for injecting secondary combustion gas through the secondary combustion gas supply path (1).
4) A garbage incinerator connected to the secondary combustion gas supply mechanism (15). 2. A gas sensor (S1) for detecting the concentration of oxygen contained in exhaust gas of the refuse incinerator (1),
Secondary combustion gas supply adjustment for adjusting the injection amount of secondary combustion gas from the secondary combustion gas supply mechanism (15) such that the oxygen concentration detected by the gas sensor (S1) is maintained at a predetermined target value. The refuse incinerator according to claim 1, further comprising a mechanism (16). 3. A temperature sensor (S2) for detecting an exhaust gas temperature of the refuse incinerator (1), wherein the exhaust gas temperature detected by the temperature sensor (S2) is maintained at a predetermined target value. The refuse incinerator according to claim 1 or 2, further comprising a secondary combustion gas supply amount adjusting mechanism (16) for adjusting an injection amount of the secondary combustion gas from the secondary combustion gas supply mechanism (15).