JPS58219316A - Fluidized bed type incinerator - Google Patents

Abstract

PURPOSE:To maintain a given temperature through stabilization of the temperature of a fluidized bed even if refuse fluctuates in a heat generating quantity, by a method wherein a part of exhaust gas is fed in a feeder to preheat and dry refuse before the refuse is charged in the incinerator, or to incinerate a part of the refuse. CONSTITUTION:When the incineration of refuse takes place, the appropriate opening of a control valve 10 for gas flow rate located in a bypass duct 9 allows to guide an appropriate quantity of a combustion exhaust gas to a drying chamber 14. Meanwhile, through working of a feeder 2, the refuse 15 makes contact with said combustion gas as it moves toward the inside of a furnace in a condition to be slowly agitated in the drying chamber 14. In this case, an evaporation of moisture in the refuse occurs. This causes moisture content to be reduced by a proper quantity when the refuse drops on a fluidized layer 5 as it is preheated and dried in the drying chamber 14, and enables to increase a low-level heat generating quantity of the treated refuse.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluidized bed incinerator for burning municipal waste.

In recent years, fluidized bed incinerators have been widely used as incinerators for municipal waste. In the case of incineration using a fluidized bed, it is important to form a stable fluidized bed, and the temperature is 600-600℃.
It is necessary to maintain the temperature at about 800°C. However, in cities, the amount of heat generated varies greatly depending on the season and region.
This variation is mainly due to variation in water content.

If the lower calorific value is 2000 k (A/kg or more), the fluidized bed temperature will rise too much and the throughput will decrease, or conversely, if the lower calorific value is less than 800 k (A/kg), the fluidized bed temperature will rise too much. As a result, it becomes impossible to maintain the fluidized bed temperature necessary to form a stable fluidized bed, and conversely, only the upper freeboard section tends to become hot.As a result, even though the upper freeboard section temperature is high, The drawback was that fuel oil and the like were often required to maintain the layer temperature.

The present invention eliminates the above-mentioned drawbacks of the conventional ones, and even if the calorific value of municipal waste fluctuates, the drying degree is controlled accordingly to adjust the calorific value, and the present invention can be applied to urban waste with a wide range of calorific value. The object of the present invention is to provide a fluidized bed incinerator that can stably maintain the temperature of the fluidized bed at a predetermined temperature.

The present invention guides a part of the combustion exhaust gas into the supply device, and adjusts the calorific value by preheating and drying the municipal waste before being put into the incinerator, or incinerating a part of it, and then inputting it into the incinerator. It is designed to keep the calorific value of input municipal waste within the following range: 1. 11 In a fluidized bed incinerator that is equipped with a fluidized bed section at the bottom of the furnace body and a freeboard section at the top, municipal waste is supplied and combusted by a supply device having an opening in the side wall of the furnace body, and an inlet of the supply device. and an exhaust gas outlet between the opening and the opening;
A part of the combustion exhaust gas in the furnace body is taken in through the opening, passed through a part of the supply device, and discharged from the exhaust gas outlet, and the flow rate of the exhaust gas discharged from the exhaust gas outlet is controlled. This fluidized bed incinerator is characterized by:

Embodiments of the present invention will be described using the drawings.

In FIG. 1, a wind box 7, an air distribution plate 6, and a fluidized bed 5 are formed in the lower part of the furnace body 3 of the fluidized bed incinerator.
The furnace body 3 has a fluidized bed section consisting of a fluidized bed chamber 24 containing a fluidized bed section 24, a seven reel board section 4 above, and an opening 2 in the side wall 25 of the furnace body 3.
Municipal waste is supplied and burned by a supply device 2 having a hopper 1, which is an inlet of the supply device 2.
An exhaust gas outlet 26 is provided between the exhaust gas outlet 26 and the opening 23, and a part of the combustion exhaust gas in the furnace body 3 is taken in from the opening 23, passed through the rear half of the supply device 2, and then discharged from the exhaust gas outlet 26. The exhaust gas outlet 26 is connected to the combustion exhaust gas duct 8 via a bypass duct 9 . A gas flow control valve 10 is provided in the nozzle pass duct 9 to control the flow rate of exhaust gas passing through the supply device 2.

13 is a noncombustible material outlet.

A drying chamber 14 is formed between the opening 23 of the supply device 2 and the exhaust gas outlet 26. The drying chamber 14 may perform pre-combustion as described below. The inside of the hopper 1 is always filled to the level of municipal waste 15 to seal the gas inside the incinerator.

11 is an in-layer temperature detector, and 12 is a flow blower.

Reference numeral 27 denotes a temperature controller, which controls the flow rate control valve 10 based on a signal obtained by the intralayer temperature detector 11.

In the incinerator configured as above, when incinerating municipal waste, the gas flow control valve 1 in the bypass duct 9
0 can be opened appropriately, an appropriate amount of combustion exhaust gas can be guided into the drying chamber 14, while the supply device 2 moves the municipal waste 15 inside the drying chamber 14 toward the furnace while being slowly stirred. At the same time, the waste comes into contact with the combustion gas, and at this time, the water in the waste evaporates. In this way, 4- Tetomi is subjected to preheating and drying action in the drying chamber 14,
When falling onto the fluidized bed 5, a suitable water-containing valve is reduced,
It becomes possible to increase the lower calorific value of treated waste. The above-mentioned amount of water evaporation is determined by the gas flow rate control valve 1 of the bypass duct 9.
By adjusting the opening degree of 0, the amount of gas introduced into the drying chamber 14 can be arbitrarily adjusted by changing the amount of gas introduced into the drying chamber 14. Furthermore, the opening degree of the gas flow rate control valve 10 can be adjusted by adjusting the opening degree of the gas flow control valve 10 using a temperature sensor inserted in the fluidized bed 5. 11, the temperature of the fluidized bed can be automatically changed within a range that maintains it optimally.

Next, an example of specific control of the flow rate control valve 10 when the calorific value of waste fluctuates using the method described above will be described below. Generally, the lower calorific value of garbage is 1500 kc+d/
If it is about 1 kg, the temperature of the fluidized bed will be about 700 to 800°C, and a stable fluidized bed can be formed. In this case, there is no need to preheat and dry the input waste. Now lower calorific value 1500
k (nf'/kg of waste, if the fluidized bed temperature is 70
Assuming that the temperature is 0° C., the flow control valve 10 of the bypass duct 9 can be set to be fully closed as shown in FIG. 2 in accordance with this temperature. At this time, since the input waste does not receive active convective contact with the burning gas in the preheating drying chamber 14, it receives only a small amount of radiant heat from the burner gas, and the lower calorific value of the input garbage is almost the same. It will fall into the fluidized bed part 5 with the same calorific value.

On the other hand, the quality of the waste has become very poor, for example, the lower heating value is 80%.
0) When the temperature drops below 9 to 0'/, the temperature of the fluidized bed 5 will fall below 600° C. if the state shown in FIG. 2 is maintained, making stable fluidization difficult. At this time, as shown in Fig. 3, the flow rate control valve 10 of the bypass duct 9 is automatically opened in accordance with the fluidized bed temperature, and combustion gas is introduced into the preheating drying chamber 14 to preheat and dry the input waste. It is possible to

The amount of introduced gas is set at the temperature of the fluidized bed (700 in this example).
℃) can be automatically controlled by the flow control valve 10.

On the other hand, when the quality of the waste becomes very good, for example when the lower calorific value exceeds 2000 kml/gradient, the temperature of the fluidized bed 5 will exceed 800°C if the condition shown in Figure 2 is maintained, and the waste will deteriorate. Clinker trouble occurs due to melting of the glass inside. At this time as well, as shown in Figure 3, the flow rate control valve 1
0 is opened and combustion gas is introduced into the preheating drying chamber 14. At this time, since the moisture content of the input waste is very low, the preheating drying chamber 14
Inside, the surface layer of the garbage dries as it comes into contact with the introduced gas, and ignition and combustion begin. Therefore, a portion of the input waste is combusted in the preheating drying chamber, and the remaining portion falls into the fluidized bed section and is burned, reducing the combustion load on the fluidized bed section and making it possible to lower the fluidized bed temperature. The amount of gas introduced at this time can be automatically controlled by the flow rate control valve 10 so that the temperature of the fluidized bed reaches a set value (700° C. in this example). It goes without saying that the set value of the temperature of the fluidized bed and the flow rate control range of the amount of bypass gas can be freely changed within a range that allows stable formation of the fluidized bed.

Other embodiments are shown in FIGS. 4 and 5. FIG. 4 shows an example in which a gas cooling chamber 17 is arranged after the incinerator 3 and a bypass duct 9 is connected to the gas cooling chamber outlet exhaust gas duct 16B. The gas cooling chamber 17 may be replaced by an air preheater or a cyclone. FIG. 5 shows an example in which a main exhaust gas flow rate side valve 18 is provided in the furnace outlet exhaust gas duct 16A, and a bypass duct 9 is connected to the rear thereof. In this example, the ratio of the main exhaust gas flow rate to the bypass exhaust gas flow rate is adjusted by simultaneously controlling the opening degrees of the two flow rate control valves 10 and 18.

FIG. 6 shows another embodiment. FIG. 6 shows an example in which a radiation control damper 19 is added to the opening 23 of the preheating drying chamber 14 as an openable and closable heat shield plate that can freely control the amount of radiant heat from the combustion chamber. The opening of the control damper 19 is adjusted by means of a suitable drive 20. In the case of this embodiment, for its purpose, the ceiling 21 of the preheating drying chamber 14 is
It is desirable to have a shape that is wide open toward the freeboard portion 4 so that it can sufficiently receive radiant heat from the inner circumferential wall.

By doing this, not only direct drying by exhaust gas but also radiant heat from the combustion chamber can be used effectively.
Effects similar to those described in the embodiment shown in the figures can be more fully exerted.

The present invention can bring about the following extremely great practical effects.

(1) By effectively using the calorific value of the combustion gas, it is possible to preheat and dry (or precombust) the material to be incinerated and maintain the optimal fluidized bed temperature.

(2) By controlling the amount of combustion gas required for preheating and drying at the fluidized bed temperature, stable operation is possible even for garbage whose calorific value fluctuates widely, and an improvement in the operating rate can be achieved.

(3) In addition, since it is possible to always maintain the optimal fluidized bed temperature for waste whose calorific value fluctuates widely, cooling of the fluidized bed is not required for waste with a high calorific value, and it is not necessary to cool the fluidized bed for waste with a low calorific value. Since fuel can be saved, operating costs can be reduced.

[Brief explanation of drawings]

The drawings relate to an embodiment of the present invention; FIG. 1 is a vertical cross-sectional flow diagram, FIGS. 2 and 3 are vertical cross-sectional flow diagrams showing its operation, and FIGS. 4, 5, and 6 are respectively FIG. 3 is a flow diagram of a different embodiment. 1. Hopper, 2. Supply device, 3. Furnace body, 4.
... Freeboard section, 5... Fluidized bed, 6... Air disperser, 7... Wind box, 8... Exhaust gas duct, 9... Bypass duct, 10... Flow rate control valve,
11...Temperature detector, 12...Flow blower, 13
...Incombustible material outlet, 14...Drying room, 15...Municipal garbage, 16A...Furnace outlet exhaust gas duct, 1613.
...Cooling chamber outlet exhaust gas duct, 17...Gas cooling chamber,
18...Flow control valve, 19...Control damper, 20.
... Drive device, 21 ... Ceiling part, 22 ... Flame, 2
3... Opening, 24... Fluidized bed chamber, 25... Side wall, 2
6...Exhaust gas outlet, 27...Temperature controller. Patent applicant: Ebara Corporation Representative Patent Attorney: Go Hatayama - Minoru 1)
1-

Claims (1)

[Claims] 1. A fluidized bed comprising a fluidized bed section below the furnace body and a 7-liquid board section above the furnace body, in which municipal waste is supplied and combusted by a supply device having an opening in the side wall of the furnace body. In the incinerator, an exhaust gas outlet is provided between the inlet of the supply device and the opening, and a part of the combustion exhaust gas in the furnace body is taken in from the opening, passes through a part of the supply device, and is discharged from the exhaust gas outlet. A fluidized bed incinerator characterized in that the flow rate of exhaust gas passing through the supply device is controlled. λ In a fluidized bed incinerator that is equipped with a fluidized bed section at the bottom of the furnace body and a freeboard section at the top, municipal waste is supplied and combusted by a supply device having an opening in the side wall of the furnace body.
An exhaust gas outlet is provided between the inlet of the supply device and the opening, and a part of the combustion exhaust gas in the furnace body is taken in from the opening, passes through a part of the supply device, and is discharged from the exhaust gas outlet. A fluidized bed incinerator, characterized in that the flow rate of exhaust gas passing through the supply device is controlled, and a heat shield plate that can be opened and closed is provided in the opening.