JPH10185178A - Exhaust control method for regenerative burner combustion system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust control method of a regenerative burner system which enables purging in a short time. SOLUTION: In an exhaust control method of a regenerative burner combustion system having a burner and a heat storage device, in the switching of a combustion side burner to the discharge of a combustion exhaust gas from the combustion, a combustion air path is closed to perform a prepurging of a fuel left in a burner body by combustion air and then, an exhaust path is opened. In switching an exhaust side burner to combustion from the discharge of the combustion exhaust gas, an exhaust system is closed to perform a post purging of the exhaust gas left in the burner body by the combustion air and then, the combustion air path is opened. Thus, the combustion gas and the combustion exhaust gas can be pushed out into a furnace by the combustion air for purging. The combustion air will not flow directly into the exhaust path thereby eliminating back fire in the exhaust path or delay in the combustion of the fuel otherwise caused by blocking by the combustion exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust control method for a regenerative burner combustion system.

[0002]

2. Description of the Related Art Conventionally, in a regenerative burner combustion system, a regenerative burner device is often arranged facing a side surface of a heating furnace. Such a regenerative burner combustion system, for example, performs an operation of supplying fuel and combustion air to a regenerative burner device on one side of a furnace to perform combustion, and sucking exhaust gas from a regenerative burner device on the opposite side. It is operated with roles alternated. As a result, the heat of the exhaust gas is stored in the regenerator of the regenerative burner device on the suction side, and is used for preheating the combustion air blown into the furnace when the combustion side is reached next time.

Here, the operation of supplying the combustion air and exhausting the combustion exhaust gas and supplying the fuel in the regenerative burner combustion system will be described with reference to FIG. In the case of burner A, first, the combustion air damper and the exhaust gas damper are closed, and the pilot valve is ignited while the fuel valve is also closed, the combustion air damper is opened, and the exhaust gas remaining in the burner body is opened. Prepurge with combustion air to push gas into furnace
Perform for 5 seconds (Tw). In this way, the exhaust gas in the burner is cleaned. Next, the fuel valve is opened to supply fuel and burn (Tf). After burning for 30 seconds, the fuel valve is closed. After closing the fuel valve, a post-purge is performed with the combustion air for 3 to 5 seconds (Tp) in order to purge unburned fuel remaining in the burner body. If post-purging is not performed sufficiently, flashback may occur in the pipe when switching to exhaust. When the post-purge is completed, the combustion air damper is closed and the exhaust gas damper is opened to exhaust the exhaust gas (TL).

[0004] This is repeated thereafter. In the case of burner B, the same operation is performed with the cycle shifted. In this case, when the electromagnetic valve for exhaust gas is opened at the same time when the electromagnetic valve for combustion air is closed, the combustion air is temporarily sucked into the exhaust system, and the gas purge by the combustion air in the burner body is delayed. Therefore, it takes a long time for gas purging.

[0005] Therefore, in one switching operation, the fuel cannot be supplied to the burner A and the burner B for about 6 to 10 seconds (Tw + Tp), and the use efficiency of the burner is not good.

[0006]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an exhaust control method for a regenerative burner system capable of purging in a short time.

[0007]

Means for Solving the Problems, Embodiments of the Invention and Effects of the Invention The invention according to claim 1 is directed to an exhaust control method for a regenerative burner combustion system having a burner and a regenerator.
When the combustion side burner is switched from combustion to exhaust of combustion exhaust gas, the combustion air path is closed and then the exhaust path is opened.

According to the first aspect of the present invention, the combustion air is not directly drawn into the exhaust path in the burner. According to a second aspect of the present invention, in the exhaust control method for the regenerative burner combustion system according to the first aspect, the fuel remaining in the burner body is pre-purged with combustion air before opening the exhaust path, and then the exhaust path is opened. Good. This ensures that the combustion air blows out the residual fuel in the burner into the furnace, so that the inside of the burner is clean and flashback to the exhaust system can be prevented.

According to a third aspect of the present invention, there is provided an exhaust emission control method for a regenerative burner combustion system having a burner and a regenerator, wherein when the exhaust-side burner is switched from exhaust flue gas to combustion, combustion air is closed and exhaust air is closed. Open the route. This prevents the combustion air from being directly drawn into the exhaust path in the burner.

According to a fourth aspect of the present invention, in the control method of the third aspect, the exhaust gas remaining in the burner main body is post-purged with combustion air before combustion, and then the fuel is burned. Good. This ensures that the combustion air blows out the residual exhaust gas in the burner into the furnace, so that the inside of the burner is clean and the next fuel ignition can be performed smoothly.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. The regenerative burner combustion system 1 of the embodiment has a configuration as shown in FIG. Burners A and B provided on the side wall of the furnace 2, a fuel supply system 10 and a combustion air supply system 20;
And a flue gas exhaust system 30.

Inside the burners A and B, the heat storage bodies 3,
4 are provided. The fuel supply system 10 includes the fuel supply port 1
1 is supplied through a pipe 12 with burners A,
B. 13 and 14 are switching solenoid valves. The combustion air supply system 20 supplies combustion air supplied from a blower 21 to burners A and B via a pipe 22. Reference numeral 23 denotes an open / close damper, and reference numerals 24 and 25 denote switching solenoid valves.

A flue gas exhaust system 30 sucks and discharges flue gas from a burner B or a burner A via a pipe 32 by a blower 31. Reference numeral 33 denotes an opening / closing damper.
5 is an electromagnetic valve. In the case of FIG. 1, the burner A side is in a combustion state, and the burner B is in a combustion exhaust gas exhaust system.

When a predetermined time comes, the respective solenoid valves are switched to burn the burner B side and at the same time burner A
The flue gas is discharged from the side. By doing so, the heat of the high-temperature exhaust gas is stored in the heat storage unit 3 or 4 when the combustion exhaust gas is discharged, and the combustion air used for the next combustion is heated.

Next, an exhaust control method for the regenerative burner combustion system will be described with reference to FIG. At first, solenoid valve 1
3, 14, 24, 25, 34, 35 and dampers 23, 3
3 is closed. Ignite the pilot burner, then
The solenoid valves 24 and 34 and the dampers 23 and 33 are opened, and pre-purge is performed for 3 to 5 seconds with the combustion air from the blower 21 in order to push the combustion exhaust gas remaining in the burner body of the burner A into the furnace ( Tw). Burner A in this way
Clean out the exhaust gas remaining inside. At the same time, exhaust gas is discharged from the blower 31 via the burner B. Next, the solenoid valve 13 is opened to supply fuel and burn (Tf). After burning for a predetermined time, the solenoid valve 13 is closed. After the solenoid valve 13 is closed, in order to purge unburned fuel remaining in the burner main body, the combustion air is continuously supplied and post-purge is performed for three times.
Perform for ~ 5 seconds (Tp). After the completion of the post-purge, the solenoid valve 34 is closed. After closing the solenoid valve 34, the solenoid valve 24 is closed and the solenoid valve 25 is opened (TL).
When the closing of the solenoid valve 24 and the opening of the solenoid valve 25 are completed, the solenoid valve 35 is opened. When the solenoid valve 35 is opened, the solenoid valve 14
Open.

Thus, the switching is completed, the burner B burns, and the burner A discharges the combustion exhaust gas. The rest is an alternating repetition of this pattern. In the embodiment, since the exhaust gas damper is opened after the combustion air damper is closed, the combustion air is not sucked into the exhaust system as in the conventional example.

Also, after the combustion exhaust gas is discharged from the burner A for 30 seconds, the burner A is burned again.
Since the electromagnetic valve 24 is opened after the valve 4 is closed, the combustion air is not sucked into the exhaust system 30 here. So,
Prepurge is quicker. In this way, the usage efficiency of the burner according to the embodiment is represented by the following expression, compared to the usage efficiency of the conventional burner represented by the following expression.

[0018]

## EQU1 ## Conventional usage efficiency = [Ts- (Tw + Tp)] /
Ts Here, Ts: switching cycle time of burners A and B Tw: pre-purge time (time for purging exhaust gas in the burner body) = [30 seconds− (3 seconds + 3 seconds)] / 30 seconds = 80%

[0019]

## EQU2 ## Usage efficiency of the embodiment = [Ts- (Tw + Tp-2)
× TL)] / Ts, where Ts: cycle time for switching burners A and B Tw: pre-purge time (time for purging exhaust gas in the burner body) Tp: post-purge time (for cleaning unburned fuel from the burner body) Time) TL: Time required to open or close the combustion air damper = [30 seconds− (3 seconds + 3 seconds−2 × 1 second)] / 30 seconds = 87% As can be seen from Equation 2, compared to the conventional example. Burner use efficiency is improved by 7%. This means that the number of burners to be installed can be reduced by 7%, or a burner having a small capacity can be used accordingly. Therefore, waste can be reduced and the equipment is advantageous.

Although the embodiment of the present invention has been described above, various embodiments can be made without departing from the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a main part of a regenerative burner combustion system according to an embodiment.

FIG. 2 is an explanatory diagram illustrating an operation of the embodiment.

FIG. 3 is an explanatory diagram showing an operation of a conventional example.

[Explanation of symbols]

1: Regeneration burner combustion system, 3, 4: Regenerator, 2
0: combustion air path, 30: exhaust path, A, B: burner.

Claims (4)

[Claims] 1. An exhaust control method for a regenerative burner combustion system having a burner and a regenerator, wherein when a combustion side burner is switched from combustion to exhaust of combustion exhaust gas, a combustion air path is closed and then an exhaust path is opened. An exhaust control method for a regenerating burner combustion system. 2. The exhaust control method for a regenerative burner combustion system according to claim 1, wherein the fuel remaining in the burner main body is pre-purged with combustion air before the exhaust path is opened, and then the exhaust path is opened. An exhaust control method for a regenerative burner combustion system. 3. An exhaust control method for a regenerative burner combustion system having a burner and a regenerator, wherein when an exhaust burner is switched from exhaust flue gas to combustion, the exhaust air path is closed before the combustion air path is opened. An exhaust control method for a regenerative burner combustion system. 4. The control method for a regenerative burner combustion system according to claim 3, wherein the exhaust gas remaining in the burner body is post-purged with combustion air before combustion, and then the fuel is burned. A control method for a regenerating burner combustion system.