JPH07103668A - Heat accumulative combustion device - Google Patents

Abstract

PURPOSE:To prevent burning of a discharged gas opening/closing valve due to combustion discharged gas by a method wherein each of input sides of a combustion air opening/closing valve and the discharged gas opening/closing valve is connected by a bypassing pipe and then combustion air of normal temperature is supplied to the discharged gas opening/closing valve through the bypassing pipe when combustion at a burner is stopped. CONSTITUTION:Combustion air is supplied through a combustion air pipe 14a having a combustion air opening/closing valve 3a installed therein is supplied to a burner 11a through a heat accumulating chamber 10a and combustion discharged gas of high temperature within a furnace 9 is passed through a heat accumulating chamber 10b and discharged out of the furnace through a discharged gas pipe 13b having a discharged gas opening/closing valve 2b. In such a heat accumulation type combustion device, bypassing pipes 15a, 15b having auxiliary opening/closing valves 16a, 16b are arranged between input sides of the combustion air opening/closing valves 3a, 3b and input sides of the discharged gas opening/closing valves 2a, 2b. Under a flame extinguishing mode of the heat accumulative combustion device, the auxiliary opening/closing valves 16a, 16b are opened to supply combustion air of normal temperature, thereby burning of the discharged gas opening/closing valves 2a, 2b due to combustion discharged gas of high temperature flowing from inside of the furnace is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage type combustor, and more particularly to a heat storage type combustor capable of reliably preventing burnout of an exhaust gas on-off valve due to high temperature combustion exhaust gas in a furnace when combustion of a burner is stopped. It is about.

[0002]

2. Description of the Related Art A heat storage type combustor is used in a heating furnace, a melting furnace and the like, and a conventional heat storage type combustor attached to the heating furnace will be described with reference to the drawings.

FIG. 4 is a sectional view of a conventional heat storage type combustor attached to a heating furnace, and FIG. 5 is a plan view of a conventional heat storage type combustor attached to a heating furnace.

In FIG. 4, 12a is a fuel gas pipe for supplying a fuel gas to a burner which will be described later, and 1a is a fuel gas pipe.
A fuel gas on-off valve provided in the middle of the fuel gas pipe 12a, 13a is an exhaust gas pipe connected to a heat storage chamber described later, 2a is an exhaust gas on-off valve provided in the middle of the exhaust gas pipe 13a, and 14a is Combustion air piping connected to the heat storage chamber, 3a is a combustion air opening / closing valve provided in the middle of the combustion air piping 14a, 4a is a pilot burner of the burner, and 5 is connected to the combustion air piping 14a. Combustion air blower, 6 is an exhaust gas blower connected to the exhaust gas pipe 13a, 7 is a damper provided on the upper wall of the furnace body 9 of the heating furnace, 8 is an actuator of the damper 7, and 10a is described later. It is a heat storage chamber attached to the burner 11a. A heat storage body 17 made of ceramic balls or ceramic honeycomb is housed inside the heat storage chamber 10a to store the high temperature exhaust gas in the furnace body 9. And 11a is a combustion burner provided on the side wall of the furnace body 9, and the already-existing heat storage chamber 10a is provided on the downstream side of the burner 11a. More than that
Although it is a constituent element for one burner, as a feature of this burner, two burners are paired, and when one is in a combustion cycle, the other is in a heat storage cycle, and combustion is alternately performed. In FIG. 4, the item with the additional number “b” relates to the other pair of burners.

As shown in FIG. 5, six heat storage type combustors having such a structure are provided on the left and right side walls of the furnace body 9 so as to face each other. That is, the furnace body 9
Is equipped with 6 pairs of heat storage type combustors. In FIG. 4, the components of the heat storage type combustor on one side wall are
The subscript a is attached and the subscript b is attached to the constituent elements of the heat storage type combustor on the other side wall.

By the conventional heat storage type combustor described above, the material to be heated such as a steel plate charged in the furnace body 9 is heated as follows.

The exhaust gas on-off valve 2a is closed, the combustion air on-off valve 3a is opened, and the combustion air is supplied from the combustion air pipe 14a to the burner 11a. After this, the fuel gas on-off valve 1a is opened with a slight delay, and the fuel gas pipe 12 is opened.
The combustion exhaust gas is supplied from a to the burner 11a. Thus, the reason why the fuel gas on-off valve 1a and the combustion air on-off valve 3a are provided with a time difference is to replace the combustion exhaust gas remaining in the heat storage chamber 10a with air before combustion. Simultaneously with the opening of the fuel gas on-off valve 1a, the pilot burner 4a is ignited. As a result, the fuel gas is ignited and the material to be heated in the furnace body 9 is heated by the one burner 11a.

The combustion exhaust gas from the burner 11a is
It flows toward the other burner 11b. However, about 20% of the total combustion exhaust gas amount is from the opened damper 7 to the furnace body 9
Released to the outside. This is because when the entire amount of combustion exhaust gas is passed through the heat storage chamber 10b, the outlet temperature of the heat storage chamber becomes too high due to the balance between the sensible heat released by the combustion exhaust gas through the heat storage cycle and the sensible heat carried away by the combustion air through the combustion cycle. Is. Therefore, about 80% of the total combustion exhaust gas amount is
It enters into the heat storage chamber 10b through the burner 11b. As a result, the heat storage body 17 in the heat storage chamber 10b is heated by the sensible heat of the combustion exhaust gas. This state is maintained until the heat storage body 17 is thermally saturated and the combustion exhaust gas temperature at the outlet of the heat storage chamber 10b starts to rise rapidly.

At the same time when the temperature of the combustion exhaust gas at the outlet of the heat storage chamber 10a starts to rise rapidly, the exhaust gas on-off valve 2a is opened to open the combustion air on-off valve 3a and the fuel gas on-off valve 1.
Close a. At the same time, the exhaust gas on-off valve 2b is closed and the combustion air on-off valve 3b is opened. Thereby, the combustion air is heated by the heat stored in the heat storage body 17 in the heat storage chamber 10b and flows toward the burner 11b. After a brief delay, the fuel gas on-off valve 1b is opened. The reason for providing the time difference between the fuel gas on-off valve 1b and the combustion air on-off valve 3b is the same as in the case described above. At the same time, the pilot burner 4b is ignited. by this,
The fuel gas is ignited, and the material to be heated in the furnace body 9 is in turn heated by the other burner 11b. in this way,
When the combustion gas from the burner 11b is burned, the heat retained by the combustion gas from one burner 11a is effectively used.

As described above, the conventional heat storage type combustor is
While one combustor of the pair is burning, the other combustor turns to the heat storage side, and after a certain period of time, this role is repeatedly changed.

In the case of having a plurality of pairs of combustors as in this example, when it is desired to reduce the combustion load of the furnace, fuel is uniformly used to some extent, that is, up to about 1/2 or 1/3 of the rating. And throttle the air volume (hereinafter referred to as turndown). If it is desired to reduce the combustion load more than that, the combustor is thinned out in a pair unit due to problems such as flame lift. For example, if you want to set the load to 1/4 of the rating,
The combustor of the / 2 pair is put in the fire extinguishing mode, and the combustor of the remaining 1/2 pair is burned with a load of 1/2 of the rated value (hereinafter referred to as burner thinning).

[0012]

However, the above-mentioned conventional heat storage type combustor has the following problems. That is, when the combustion load of the furnace is reduced by the burner thinning operation described above, the high-temperature combustion exhaust gas in the furnace is thinned out and flows into the exhaust gas on-off valves 2a, 2b of the combustor in the fire extinguishing mode, whereby The heat-sensitive parts such as the valve seats of the exhaust gas on-off valves 2a and 2b and the seal portion of the valve rod are burned. The high temperature combustion exhaust gas in the furnace flows into the exhaust gas on-off valves 2a and 2b of the combustor in the fire extinguishing mode because the exhaust gas blower 6 is used in common in all combustors. This is because the suction force is always acting on the exhaust gas on-off valves 2a and 2b of the combustor.

Accordingly, an object of the present invention is to provide a heat storage type combustor which can reliably prevent the exhaust gas on-off valve of the combustor in the fire extinguishing mode from being burnt out by the high temperature combustion exhaust gas in the furnace.

[0014]

According to the present invention, a burner for heating a material to be heated charged in a furnace by burning a combustion gas, and a heat storage chamber provided on the downstream side of the burner. A combustion air pipe for supplying combustion air to the burner through the heat storage chamber; a combustion air opening / closing valve provided in the middle of the combustion air pipe; and a high temperature combustion exhaust gas in the furnace body. An exhaust gas pipe for discharging to the outside of the furnace body via a heat storage chamber, and a heat storage type combustor consisting of an exhaust gas on-off valve provided in the middle of the exhaust gas pipe, the inlet side of the combustion air on-off valve and the A bypass pipe is connected to the inlet side of the exhaust gas on-off valve, an auxiliary on-off valve is provided on the bypass pipe, and when combustion of the burner is stopped, the auxiliary on-off valve is opened to operate the combustion air pipe. The normal temperature of the combustion air supplied to the inlet side of the exhaust gas on-off valve, thus, it has the characteristics to prevent burning of the furnace body of the exhaust gas on-off valve by the combustion exhaust gas temperatures.

[0015]

[Function] A bypass pipe is provided between the inlet side of the combustion air on-off valve and the exhaust gas on-off valve, and an auxiliary on-off valve is provided on the bypass pipe. When the burner stops combustion, the auxiliary on-off valve is opened. When the combustion air at normal temperature is supplied to the inlet side of the exhaust gas on-off valve, the high temperature combustion exhaust gas in the furnace does not flow into the exhaust gas on-off valve. Therefore, it is possible to prevent the exhaust gas on-off valve from burning.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the heat storage type combustor of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a heat storage type combustor of the present invention installed in a heating furnace, and FIG. 2 is a plan view of the heat storage type combustor of the present invention installed in a heating furnace.

1 and 2, FIGS. 4 and 5
The same reference numerals as in 1 indicate the same items, and the description thereof will be omitted. Reference numerals 15a and 15b are bypass pipes provided between the inlet sides of the combustion air on-off valves 3a and 3b and the exhaust gas on-off valves 2a and 2b, and 16a and 16b are connected to the bypass pipes 15a and 15b. It is an auxiliary on-off valve provided.

The state of the combustion mode of the heat storage type combustor of the present invention described above is the same as that of the conventional heat storage type combustor, and therefore the description thereof is omitted. When the heat storage type combustor is in the fire extinguishing mode, that is, when it is thinned out, the auxiliary opening / closing valves 16a, 1
Open 6b. Thereby, the combustion air pipes 14a, 14
Since the combustion air at room temperature is supplied to the inlet side of the exhaust gas on-off valves 2a, 2b from b, it is possible to prevent the hot combustion exhaust gas from the furnace from flowing into the exhaust gas on-off valves 2a, 2b. As a result, it is possible to reliably prevent the exhaust gas on-off valves 2a, 2b from being burnt out by the high-temperature combustion exhaust gas from the furnace.

If the amount of combustion air supplied to the inlet side of the exhaust gas on-off valves 2a, 2b is small, the auxiliary on-off valve 16
There is no problem even if a and 16b are omitted and the combustion air is continuously supplied to the inlet side of the exhaust gas on-off valves 2a and 2b even when not in the fire extinguishing mode.

FIG. 3 shows an example of the actual value of the temperature change immediately before the exhaust gas on-off valve. As is clear from FIG. 3, according to the heat storage type combustor of the present invention, it is clear that the temperature immediately before the exhaust gas on-off valve does not rise even if time elapses after the extinguishing mode is entered.

[0022]

As described above, according to the present invention, the bypass pipe is provided between the inlet side of the combustion air on-off valve and the exhaust gas on-off valve, and the bypass pipe is provided with the auxiliary on-off valve. When the combustion of the burner is stopped, if the auxiliary on-off valve is opened and the combustion air at room temperature is supplied to the inlet side of the exhaust gas on-off valve, the hot combustion exhaust gas in the furnace does not flow to the exhaust gas on-off valve. Therefore, there is a useful effect that the burnout of the exhaust gas on-off valve can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of a heat storage type combustor of the present invention installed in a heating furnace.

FIG. 2 is a plan view of the heat storage type combustor of the present invention installed in a heating furnace.

FIG. 3 is a bluff showing a relationship between a temperature immediately before an exhaust gas on-off valve and an elapsed time after a fire extinguishing mode is set.

FIG. 4 is a cross-sectional view of a conventional heat storage combustor attached to a heating furnace.

FIG. 5 is a plan view of a conventional heat storage type combustor attached to a heating furnace.

[Explanation of Codes] 1: Fuel gas on-off valve, 2: Exhaust gas on-off valve, 3: Combustion air on-off valve, 4: Pilot burner, 5: Combustion air blower, 6: Exhaust gas blower, 7: Damper, 8: Activator, 9: Furnace body, 10: Heat storage chamber, 11: Burner, 12: Fuel gas pipe, 13: Exhaust gas pipe, 14: Combustion air pipe, 15: Bypass pipe, 16: Auxiliary on-off valve, 17: Heat storage body.

Claims (1)

[Claims] 1. A burner for heating a material to be heated charged in a furnace by burning a combustion gas, a heat storage chamber attached to the burner, and the burner via the heat storage chamber. Combustion air piping for supplying combustion air, a combustion air opening / closing valve provided in the middle of the combustion air piping, and high temperature combustion exhaust gas in the furnace body are discharged to the outside of the furnace body through the heat storage chamber. In the heat storage combustor consisting of an exhaust gas pipe for, and an exhaust gas on-off valve provided in the middle of the exhaust gas pipe, between the inlet side of the combustion air on-off valve and the inlet side of the exhaust gas on-off valve The bypass pipes are connected to each other, and an auxiliary opening / closing valve is provided in the bypass pipe. When combustion of the burner is stopped, the auxiliary opening / closing valve is opened to open / close the combustion air at room temperature from the combustion air pipe for the exhaust gas. The supply to the inlet side, thus, regenerative combustor, characterized in that to prevent the burning of the furnace body of the exhaust gas on-off valve by the combustion exhaust gas temperatures.