JPS5986801A - Gas recirculation type boiler device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas recirculation boiler device, and in particular, when the gas recirculation fan is stopped, high-temperature combustion air from the forced draft fan is passed through an air preheater. The present invention relates to a gas recirculation boiler device suitable for preventing backflow of furnace gas by guiding a portion of the secondary air to the discharge side system of the gas recirculation fan.

Conventional gas recirculation boiler devices of this type burn fuel I7 to heat fluid such as water in a container and then transfer the heated fluid such as hot water or steam to other external equipment (such as a boiler that supplies IC). , the combustion air necessary for combustion of fuel in the boiler is pressurized by a forced draft fan, and the secondary air is made to a height of 171A through an air preheater, and the combustion air is supplied to the boiler via an air duct. & 1ift: and an exhaust gas supply device which pressurizes a part of the exhaust gas discharged from the boiler with a gas recirculation fan and supplies the same to the furnace of the boiler and the secondary air for combustion through each air passage. , it is common for the configuration TI to include the following.

Doo, the above gas recirculation boiler device i'? t, J-
When the operation of the gas recirculation fan described in 1L is stopped, in order to protect the fan from the backflow of furnace gas from the boiler, a separate air duct for supplying cold air from the discharge side of the forced draft fan is installed. It is configured to be introduced into the air passage of the discharge side system of the gas recirculation fan through the gas recirculation fan and sealed.

In addition to providing the above-mentioned seal structure, it is also necessary to increase the discharge pressure of the gas recirculation fan due to the adoption of a method in which a part of the exhaust gas is mixed into the secondary air of the combustion air. Therefore, while the gas recirculation fan is in operation, depending on the boiler load and the amount of gas recirculation, the discharge pressure of the forced draft fan may be lower than the discharge pressure of the gas recirculation fan. be.

In such a case, the gas reaches the dew point due to the breathing phenomenon of the furnace gas and the cold air around the seal damper of the gas recirculation fan, and the discharge side of the gas recirculation fan This has the disadvantage that it adheres to the seal damper and the air duct of the seal portion, causing corrosion there.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, prevent the furnace gas from flowing back toward the gas recirculation fan, and prevent the breathing phenomenon between the furnace gas and cold air to eliminate corrosion. The object of the present invention is to provide a gas recirculation boiler device.

In order to achieve the above object, the present invention supplies a portion of the high temperature secondary combustion air to the gas recirculation amount r5 (the discharge side system of the machine) through the exhaust gas mixing system when the gas recirculation fan is stopped. It is designed so that it can be introduced into the

Hereinafter, preferred embodiments of the present invention will be described based on the drawings, but before that, the matters on which the present invention is based will be described.

FIG. 1 is a system diagram showing an example of a gas recirculation boiler device row, which is the basis of the present invention.

In FIG. 1, reference numeral 1 denotes a boiler, and the boiler 1 is configured to heat a fluid in a container (not shown) by burning fuel, and to supply the heated fluid to others. The boiler 1 is provided with a wind box 2. In the wind box 2,
The air passage is connected so that secondary combustion air out of the combustion air pressurized by the forced draft fan 3 is supplied via the air preheater 4 and the exhaust gas mixer 5, thereby creating a combustion air supply device. It is configured as. Most of the exhaust gas discharged from the boiler 1 is configured to be discharged from a chimney (not shown) through an air preheater 4 by an induced draft fan (not shown). Further, a part of the exhaust gas discharged from the boiler 1 is pressurized by a gas recirculation fan 6 and supplied to the combustion secondary air and the furnace of the boiler 1], the gas recirculation fan 6 is in contact with an air duct 100 of an exhaust gas mixing system and an air duct 200 of a system for supplying exhaust gas to the furnace of the boiler 1 via its discharge rodan puff. An exhaust gas mixing damper 8 is provided in the wind path 100 of the exhaust gas mixing system, and a furnace hopper inlet damper 9 is provided in the path 200 of the system that supplies exhaust gas to the furnace. Wind ducts 100 and 2 of each system
00 and the gas recirculation ventilator discharge rodanopa 7, in other words, the air duct of the discharge side system of the gas recirculation ventilator 6 is filled with combustion air pressurized by the forced draft fan 3. A part of the cold air is supplied through a seal air passage 300 provided with a seal damper 10.

According to the gas 1-air circulation fLlj type boiler apparatus configured in this way, the discharge pressure of the gas recirculation fan 6 needs to be raised in order to mix the exhaust gas into the secondary combustion air. As a result, during the operation of the gas recirculation fan 6, depending on the load of the boiler 1 and the amount of gas recirculation, the forced draft fan 3
There may be cases where the discharge pressure of the gas recirculation fan is lower than the discharge pressure of the gas recirculation fan. In such a case, in the vicinity of the seal damper 10 of the seal gl and path 300 that introduces cold air, the gas reaches the dew point due to the breathing phenomenon of the furnace gas and cold air, corroding the surrounding area of the damper 10. Te1~'? f. Something happened.

FIG. 2 is a system diagram showing an embodiment of the gas recirculation Jj:i type boiler apparatus according to the present invention.

In the embodiment shown in FIG. 2, the same components as those in the embodiment shown in FIG.

The embodiment shown in FIG. 2 differs from the embodiment shown in FIG. In addition to stopping the introduction of cold air that had been supplied to the exhaust gas mixing system, the exhaust gas mixing Danno 7 80 installed in the air passage 100 of the exhaust gas mixing system is equipped with a minimum stopper and is fully closed even when the gas recirculation fan 6 is stopped. The only difference is that the high-temperature combustion secondary air is introduced into the discharge side system of the gas recirculation fan 6 without any changes in the other configurations.

The operation of the gas recirculation type litchi loading constructed in this way will be explained below.

When the gas recirculation fan 6 is stopped, the gas recirculation fan 6
The discharge rodan puff is fully closed, and the secondary air pressure from the air preheater 4 is surely higher than the gas pressure on the discharge port side of the gas recirculation fan 6.

Therefore, even when the gas recirculation fan 6 is stopped, the exhaust gas mixing damper 80 is not completely closed, but the minimum stopper (not shown) is used to maintain the necessary opening degree to ensure the sealing amount. This allows high temperature secondary air to flow into the discharge system of the gas recirculation fan 6 and into the furnace of the boiler 1 via the furnace hopper artificial damper 9. As a result, backflow of furnace gas toward the gas recirculation fan 6 can be prevented.

Furthermore, there is no need to provide a sealing air duct 300 for introducing cold air, and there is no contact between the cold air and the furnace gas, so the sealing air duct 300 and the seal damper 10 are not corroded. be. Furthermore, the seal air passage 3
00 and the seal damper 10, the number of members can be reduced and the device configuration can be simplified.

As described above, according to the present invention, a part of the high temperature secondary combustion air can be introduced into the discharge side system of the gas recirculation fan through the exhaust gas mixing system, so that the sealing air duct can be There is no need to provide a sealing air duct and a sealing damper, and there is an effect that corrosion of the sealing air duct and the sealing damper is reduced, and the device configuration becomes extremely simple.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an example of the gas recirculation boiler Afil: which is the basis of the present invention, and Fig. 2 is a system diagram showing an example of the gas recirculation boiler device flJ according to the present invention. It is a diagram. 1... Boiler, 2... Wind box, 3...
Push-through machine a, 4...Air preheating 2=, 5...
Exhaust gas mixer, 6... Gas recirculation fan, 7.
・・Air ventilator discharge rotary turn from gas re-shield, 80...4
Jl-Gas Mixing Danno ζ, 100...Exhaust gas mixing system wind duct. 41+, person 8') Numa Tatsuno'ba l II Figure 2

Claims (1)

[Claims] (1) Burning fuel to heat the fluid in the container
(A boiler that supplies fluid to others, and a forced draft fan that pressurizes the combustion air necessary for combustion of fuel in the boiler,
A combustion air supply device that preheats secondary combustion air of the combustion air with an air preheater and supplies it to the boiler, and a gas recirculation ventilator that supplies the −° part of the exhaust gas discharged from the 7Iζ boiler. In the gas recirculation type boiler device configured to include a flue gas supply bag f1t which is pressurized by a pressure and supplied to the furnace of the boiler and the secondary combustion air, the forced draft The air preheater of the combustion air from the machine is heated to tEi 5. - A part of the secondary combustion air for r? is passed through the exhaust gas mixing system. A gas recirculation fl-+ type boiler apparatus characterized in that the gas recirculation fan side system is configured as follows.