JP2668630B2 - Secondary air supply method for combustion furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

INDUSTRIAL APPLICABILITY The present invention can be used for supplying secondary air to all combustion systems such as refuse incinerators, waste incinerators, coal combustion furnaces, oil combustion furnaces, etc. The present invention relates to a secondary air supply method that enables stable and safe combustion regardless of fluctuations and load fluctuations.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
2 was supplied with secondary air. 16 and 18 are secondary air supply ports. In the steady state, stable and safe combustion was possible by the supply of the secondary air as shown in FIG. When the calorific value or load of the combustion material fluctuates, the amount of secondary air supplied is controlled by adjusting the air volume of the blower. Further, in JP-A-3-170715, the pressure in the fluidized bed incinerator is measured, and the measurement signal is processed to detect the primary combustion state of the incineration object, and based on the primary combustion state. Then, a combustion control method is described in which the amount of secondary air for combustion is appropriately adjusted to generate secondary combustion of combustible gas to prevent incomplete combustion in the furnace.

[0003]

In the above prior art, when the heat value or load of the combustion product fluctuates, the number of secondary air ports to be used remains fixed and only the air volume of the blower is used to generate the secondary air. Since the supply amount was controlled, when the calorific value or the load of the combustion product was reduced, the flow rate of the secondary air was reduced together with the supply amount of the secondary air, as shown in FIG. Therefore, the penetrating force of the secondary air in the furnace becomes small, the agitation in the furnace becomes insufficient, and problems such as central blow through occur as shown in FIG. 6, and incomplete combustion easily occurs. 33 is a central blow-through portion. As described above, in the conventional techniques shown in FIGS. 5 and 6, the number of secondary air ports used is fixed, and the supply amount of the secondary air is controlled only by the air volume of the blower. It was not possible to change the heat generation amount or load of the device so much. The present invention has been made in view of the above points, detects the pressure of the secondary air in the secondary air supply pipe ,
By controlling the number of secondary air ports that supply the secondary air and keeping the flow velocity of the secondary air ports almost constant, the penetrating force of the secondary air is maintained even if the calorific value of the combustion product and load fluctuations are large. It is an object of the present invention to provide a secondary air supply method for a combustion furnace which prevents incomplete combustion and enables stable and safe combustion.

[0004]

In order to achieve the above object, a secondary air supply method for a combustion furnace according to the present invention comprises a combustion furnace having a plurality of secondary air ports as shown in FIGS. In the secondary air supply method of the furnace, the secondary air supply line in the secondary air supply line due to the fluctuation of the calorific value of the combustion material and / or the load
Detects air pressure fluctuations and detects combustion state fluctuations,
Based on this, the number of secondary air ports for supplying the secondary air is controlled, and the secondary air is appropriately adjusted and supplied so as to keep the secondary air port flow rate substantially constant while maintaining a stable combustion state. It is characterized by that.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. However, the shapes of the components described in this embodiment, the relative arrangement thereof, and the like are not intended to limit the scope of the present invention to them only, unless otherwise specified, and are merely illustrative examples. It's just Embodiment 1 This embodiment is a case where secondary air is supplied in a fluidized bed combustion furnace as shown in FIG. In FIG. 1, 30
Denotes a combustion furnace, which has a wind box 38, a dispersion plate 40, and a fluidized bed 42, and a push blower 34 for ejecting primary air is connected to a lower portion thereof. The freeboard section 32 of the combustion furnace 30 is provided with secondary air supply ports 16, 18, and 20 for supplying secondary air. Port 1
6, 18, and 20 communicate with the secondary air supply pipe 22 through valves 10, 12, and 14, respectively, and are connected to the secondary blower 36. Reference numeral 24 denotes a pressure indicator for detecting the pressure of the secondary air. Reference numeral 26 denotes a valve which opens and closes the valves 10, 12, 14 based on the detection value of the pressure indicator 24.
It is a controller for controlling the number of 8, 20.

In FIG. 1, three valves 10, 12, 14 at the upper, middle, and lower positions are opened in a steady state, and three ports 16,
Secondary air is supplied from 18 and 20. in this case,
As shown in FIG. 3, since the penetration force of the secondary air in the furnace is large and stirring is sufficiently performed, incomplete combustion does not occur. However, FIG. 3 shows a case where ports are provided in two stages for the sake of simplicity. However, when the calorific value of the supplied combustion product becomes small or the load becomes small, it is necessary to reduce the supply amount of the secondary air, and the pressure indicator 24 causes the pressure of the secondary air supply pipe 22 to decrease. And one or two of the valves 10, 12, 14 are detected by the controller 26.
By closing the individual valves, incomplete combustion is prevented by controlling the secondary air flow rate in the furnace to be maintained. FIG. 4 shows that at a low calorific value and / or a low load,
A state in which the number of ports is controlled to maintain the secondary air flow rate in the furnace and stirring is sufficiently performed is shown. Even in this case, the central atrium does not occur. The same applies to the case where the push-in blower 34 and the secondary blower 36 are shared.

Embodiment 2 This embodiment is directed to a case where secondary air is supplied in a stoker type combustion furnace as shown in FIG. In FIG. 2, 3
Reference numeral 0 is a combustion furnace, which has a combustion material inlet 44 and a stoker 46. The freeboard section 32 of the combustion furnace 30 has secondary air supply ports 16 and 18 for supplying secondary air.
Is provided. Ports 16 and 18 are each valve 1
It is connected to the secondary air supply pipe 22 through 0 and 12 and is connected to the secondary blower 36. Reference numeral 24 is a pressure indicator for detecting the pressure of the secondary air, and 26 is a pressure indicator 2
Based on the detection value of 4, open and close the valves 10 and 12 and port 1
It is a controller for controlling the number of 6, 18. Other configurations and operations are the same as those of the first embodiment.

[0008]

As described above, the present invention has the following effects. (1) Since the flow velocity of the secondary air can be kept almost constant, even if there are large fluctuations in the calorific value of the combustion products and fluctuations in the load, stirring in the furnace is always sufficient and incomplete combustion in the combustion furnace is prevented. And stable and safe combustion can be achieved. (2) Secondary air is detected by detecting the combustion state from the pressure of the secondary air.
Since the supply amount and flow rate of air are controlled,
Even if the load decreases, the penetration force of the secondary air in the furnace is
Large agitation is sufficient and incomplete combustion does not occur.
No.

[Brief description of the drawings]

FIG. 1 is an elevation explanatory view showing an example of a fluidized bed type combustion furnace for implementing a secondary air supply method for a combustion furnace according to the present invention.

FIG. 2 is an elevation explanatory view showing an example of a stoker-type combustion furnace for implementing the secondary air supply method for a combustion furnace according to the present invention.

FIG. 3 is an elevational explanatory view showing a steady state when the secondary air supply method for a combustion furnace of the present invention is performed.

FIG. 4 is an elevational explanatory view showing a state at the time of low heat generation and / or low load when the secondary air supply method for a combustion furnace of the present invention is performed.

FIG. 5 is an elevational explanatory view showing a steady state state when a conventional secondary air supply method for a combustion furnace is performed.

FIG. 6 is an elevation explanatory view showing a state of a low heat value and / or a low load when a conventional secondary air supply method for a combustion furnace is performed.

[Explanation of symbols]

 10 valves 12 valves 14 valves 16 ports 18 ports 20 ports 22 secondary air supply pipe 24 pressure indicator 26 controller 30 combustion furnace 32 freeboard part 34 forced air blower 36 secondary air blower 38 wind box 40 dispersion plate 42 fluidized bed 44 combustion Object inlet 46 Stalker

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiko Yoshii 2-5-25 Tenjinbashi, Kita-ku, Osaka Kawasaki Heavy Industries, Ltd. Osaka Design Office (56) Reference JP-A-3-170715 (JP, A) Kaihei 4-324015 (JP, A)

Claims (1)

(57) [Claims] 1. A secondary air supply method for a combustion furnace having a plurality of secondary air ports, wherein a pressure fluctuation of secondary air in a secondary air supply line due to fluctuations in the calorific value of combustion products and / or load fluctuations is detected. Control the number of secondary air ports that supply secondary air based on this to maintain a stable combustion state
A secondary air supply method for a combustion furnace, wherein secondary air is appropriately adjusted and supplied so as to keep a secondary air port flow rate substantially constant while the secondary air port is kept at a constant flow rate.