JPH09318005A - Boiler equipment - Google Patents

Abstract

(57) Abstract: In a regenerative air preheater, the temperature of exhaust gas is not lowered so much and the temperature of exhaust gas introduced into a dust collector is sufficiently lowered. Exhaust gas GE discharged from a boiler body 1
The exhaust gas GE whose temperature has dropped by the regenerative air preheater 7 and the regenerative air preheater 7 for preheating the combustion air A fed to the boiler body 1 through the combustion air duct 11 to the exhaust gas duct 6 in which An exhaust gas cooler 14 for cooling the exhaust gas GE is provided between the dust collector 8 and the regenerative air preheater 7 of the exhaust gas duct 6,
A heat exchanger 21 that heats the combustion air A is provided upstream of the regenerative air preheater 7 of the combustion air duct 11 in the air flow direction so that the water W can circulate between the heat exchanger 21 and the exhaust gas cooler 14. To

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a boiler facility.

[0002]

2. Description of the Related Art An example of a conventional boiler equipment is shown in FIG. 4, in which 1 is a boiler body. Then, the boiler body 1
Is connected to the furnace 3 in which the fuel injected from the burner 2 installed in the lower front surface is burned to generate the combustion gas GB, the sub-side wall 4 connected to the upper rear of the furnace 3, and the rear part of the sub-side wall 4. The rear heat transfer section 5 is provided. Thus, the peripheral wall of the rear heat transfer section 5 as well as the furnace 3 and the secondary side wall 4 is formed into a panel shape by the furnace wall tube, and a superheater and a reheater are provided in the upper part of the furnace 3 and the rear heat transfer section 5. Containers, economizers, etc. are stored.

An exhaust gas duct 6 for sending combustion gas GB descending from the rear heat transfer section 5 as an exhaust gas GE is connected to the lower portion of the rear heat transfer section 5, and the exhaust gas duct 6 is connected to the exhaust gas duct 6. The regenerative air preheater 7, the dust collector 8 and the like are sequentially connected from the upstream side to the downstream side in the flow direction, and the downstream end of the exhaust gas duct 6 in the exhaust gas flow direction is connected to the chimney 9.

A wind box 10 for feeding the combustion air A into the furnace 3 is provided at the burner 2 mounting portion on the front surface of the furnace 3, and the combustion air A is sent to the wind box 10 in the wind box 10. A combustion air duct 11 for feeding is connected.

A strong pressure aerator 12 is connected to the upstream end of the combustion air duct 11 in the combustion air feed direction.
The steam air preheater 13 and the regenerative air preheater 7 are sequentially connected to the combustion air duct 11 from the upstream side to the downstream side in the combustion air supply direction.

The fuel injected from the burner 2 into the furnace 3 passes from the combustion air duct 11 through the wind box 10 to the furnace 3.
Combustion gas GB is generated by mixing with combustion air A introduced into the interior and burning.

Thus, the generated combustion gas GB is supplied to the furnace 3
And goes up from the furnace 3 through the secondary side wall 4 to the rear heat transfer part 5
Flows into the exhaust gas duct 6 as exhaust gas GE.

Exhaust gas GE discharged to the exhaust gas duct 6
Is the regenerative air preheater 7 in the combustion air duct 1
1 is preheated to lower the temperature to a predetermined temperature and then introduced into the dust collector 8. The dust is removed by the dust collector 8 and the chimney 9 is further passed through the exhaust gas duct 6.
Is discharged to the atmosphere through the chimney 9.

On the other hand, the combustion air A fed to the combustion air duct 11 by the high-pressure air blower 12 is preheated by the steam type air preheater 13 and further predetermined by the regenerative air preheater 7 as described above. Preheated to temperature, combustion air duct 11
Is fed into the furnace 3 through the wind box 10.

A fluid such as water or steam flowing in the furnace wall tube of the boiler body 1, the auxiliary side wall 4, and the rear heat transfer section 5, a superheater,
The fluid flowing through the reheater and the economizer is heated or overheated by the combustion gas GB.

[0011]

In the above-mentioned boiler equipment, the temperature of the exhaust gas GE introduced into the dust collector 8 cannot raise the upper limit in terms of dust collection, and the exhaust gas GE is discharged at the outlet of the regenerative air preheater 7. It is necessary to lower the temperature to about 110-120 ° C.

However, when a fuel containing a large amount of sulfur such as heavy oil is used as the fuel injected from the burner 2, the temperature of the exhaust gas GE is cooled at the outlet of the regenerative air preheater 7 (not shown). When the temperature is lowered to 110 to 120 ° C. by a furnace, the components in the exhaust gas GE are condensed and ash containing sulfur adheres to the element on the outlet side of the regenerative air preheater 7,
The element is clogged.

Therefore, the element of the regenerative air preheater 7 is washed with water to remove ash, but sulfuric acid is generated by the washing to accelerate corrosion of the element, which shortens the life of the element and stops the plant. However, there is a problem that the maintenance cost increases due to the loss due to the element replacement and the element replacement.

In view of the above situation, the present invention raises the temperature of the exhaust gas at the outlet of the regenerative air preheater so that the elements of the regenerative air preheater are not clogged and the exhaust gas introduced into the dust collector is discharged. The purpose is to allow the temperature to drop to a predetermined temperature.

[0015]

SUMMARY OF THE INVENTION The present invention is an air preheater for preheating combustion air fed to a boiler body through a combustion air duct to an exhaust gas duct through which exhaust gas discharged from a boiler body flows. Along with providing the exhaust gas duct, a dust collector that can introduce the exhaust gas whose temperature has dropped in the air preheater is provided, and an exhaust gas cooler that cools the exhaust gas between the air preheater and the dust collector of the exhaust gas duct is provided,
A heat exchanger for heating the combustion air is provided on the upstream side of the air preheater connection part of the combustion air duct in the air flow direction so that a predetermined medium can circulate between the heat exchanger and the exhaust gas cooler. A medium circulation pipe is provided.

In the present invention, a temperature detector is provided on the exhaust gas cooler outlet side of the exhaust gas duct so that the opening can be adjusted at a required position of the medium circulation pipe based on the valve opening command signal from the temperature detector. It is advisable to provide a flow rate control valve of the above type, and further to provide a soot blower for removing the ash attached to the cooling pipe on the inlet side of the exhaust gas cooler.

In the present invention, the exhaust gas whose temperature has been lowered by the air preheater is further cooled by the exhaust gas cooler and then introduced into the dust collector.

Therefore, in the present invention, since the temperature of the exhaust gas at the outlet of the air preheater can be increased, the element of the air preheater is not clogged, and the exhaust gas introduced into the dust collector is controlled to a predetermined level. Since it can be lowered to the temperature, it does not adversely affect the dust collector.

A flow rate control in which a temperature detector is provided on the exhaust gas cooler outlet side of the exhaust gas duct and the opening can be adjusted at a required position of the medium circulation pipe based on a valve opening command signal from the temperature detector. If a valve is provided, the temperature of the exhaust gas introduced into the dust collector can be accurately controlled, and if a soot blower that removes ash adhering to the cooling pipe is provided on the inlet side of the exhaust gas cooler, the exhaust gas cooler can be cooled. The ash attached to the tube can be easily and surely removed.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 3 show an example of an embodiment of the present invention, in which 14 is an exhaust gas cooler installed in a portion of the exhaust gas duct 6 between the regenerative air preheater 7 and the dust collector 8. is there.

As shown in FIGS. 2 and 3, the exhaust gas cooler 14 penetrates the exhaust gas duct 6 vertically in the vertical direction and is arranged at predetermined intervals in the longitudinal direction and the width direction of the exhaust gas duct 6. The stationary soot blower, which is provided with the cooling pipe 15 and is arranged at a predetermined interval in the width direction of the exhaust gas duct 6 in parallel with the cooling pipe 15 on the upstream side of the cooling pipe 15 on the most upstream side in the exhaust gas flow direction. 16, the compressed air AC supplied from an air source (not shown) is supplied from the nozzle 16a of the stationary soot blower 16 to the cooling pipe 15
The ash adhering to the cooling pipe 15 can be blown off by spraying.

The lower end and the upper end of each cooling pipe 15 respectively have a plurality of sets of headers 17, 18 extending in the width direction of the exhaust gas duct 6.
The header 17 merges and is connected to the water circulation pipe 19, and the header 18 merges and is connected to the water circulation pipe 20.

A heat exchanger 21 is provided on the upstream side in the air flow direction of the portion of the combustion air duct 11 where the steam type air preheater 13 is provided.

As shown in FIG. 2, the heat exchanger 21 vertically penetrates the combustion air duct 11 vertically and is arranged at predetermined intervals in the longitudinal direction and the width direction of the combustion air duct 11. A large number of heat radiating pipes 22 with fins 22a are provided, and the upper and lower ends of the heat radiating pipes 22 are connected to a plurality of headers 23, 24 extending in the width direction of the combustion air duct 11, respectively, and the headers 23 are joined to each other. Is connected to the water circulation pipe 20, and the header 24 is joined and connected to the water circulation pipe 25.

The tip of the water circulation pipe 25 is connected to a water tank 26 which receives the water W after the combustion air duct 11 radiates heat through the radiation pipe 22 to heat the combustion air A, and the lower end of the water tank 26 is connected. The rear end of the water circulation pipe 19 is connected to the.

In the middle of the water circulation pipe 19, there is a circulation pump 27 for feeding the water W to the exhaust gas cooler 14 and a water circulation for maintaining the temperature of the exhaust gas GE after passing through the exhaust gas cooler 14 at a predetermined temperature. A flow rate control valve 28 that adjusts the flow rate of the water W flowing through the pipe 19 is provided.

Further, a temperature detector 29 is provided downstream of the exhaust gas cooler 14 of the exhaust gas duct 6, and the temperature detector 29 is provided.
The valve opening degree command signal V detected in step 1 can be given to the flow rate control valve 28.

Thus, in the present embodiment, the exhaust gas cooler 14, the heat exchanger 21, the water tank 26, the circulation pump 27, the water circulation pipes 20, 25 and 19, the flow control valve 28,
An exhaust gas temperature reduction device 30 is constituted by the temperature detector 29 and the like.

Next, the operation of the present invention will be described.

The fuel injected from the burner 2 into the furnace 3 passes through the combustion air duct 11 and the wind box 10 and the furnace 3
Combustion gas GB is generated by mixing with combustion air A introduced into the interior and burning.

Thus, the generated combustion gas GB is supplied to the furnace 3
And goes up from the furnace 3 through the secondary side wall 4 to the rear heat transfer part 5
Flows into the exhaust gas duct 6 as exhaust gas GE.

Exhaust gas GE discharged to the exhaust gas duct 6
Is the regenerative air preheater 7 in the combustion air duct 1
1 is preheated, then cooled in the exhaust gas cooler 14 of the exhaust gas temperature reduction device 30 to lower the temperature to a predetermined temperature and then introduced into the dust collector 8.
Dust is removed by the dust collector 8 and further the exhaust gas duct 6
It is sent to the chimney 9 (see FIG. 4) through the gas and is discharged from the chimney 9 into the atmosphere.

On the other hand, the combustion air A sent to the combustion air duct 11 by the high-pressure blower 12 is heated by the heat exchanger 21 of the exhaust gas temperature reduction device 30 provided in the middle of the combustion air duct 11. Further, the steam type air preheater 13 is preheated to a predetermined temperature, and the combustion air duct 11 to the wind box 10
And is fed into the furnace 3.

Since the temperature of the exhaust gas GE does not drop so much in the regenerative air preheater 7, ash containing sulfur does not adhere to the element on the outlet side of the regenerative air preheater 7, and therefore the regenerative air preheater is not heated. The element of the container 7 is not corroded by sulfuric acid or the like, and the element has a long life.

The exhaust gas GE introduced into the dust collector 8 is
Since the exhaust gas temperature reduction device 30 can sufficiently lower the temperature, the dust collector 8 is not adversely affected by the high temperature.

In the exhaust gas temperature reducing device 30, FIG.
The water W in the water tank 26 as shown in FIG.
Is sucked into and pressurized by the exhaust gas cooler 14 from the header 17 through the water circulation pipe 19 provided with the flow control valve 28.
The temperature of the exhaust gas GE that is fed to the cooling pipe 15 and flows through the exhaust gas duct 6 is lowered to a predetermined temperature. As a result, the water W is heated to a high temperature.

The hot water W is discharged from the header 18, passes through the water circulation pipe 20, flows from the header 23 into the heat radiating pipe 22 of the heat exchanger 21, and flows through the combustion air duct 11 for combustion air. Heat A, header 24, water circulation pipe 2
It returns to the water tank 26 through 5.

The temperature of the exhaust gas GE after exiting the exhaust gas cooler 14 is detected by a temperature detector 29 and is given to the flow rate control valve 28 as a valve opening degree instruction signal V.
Is adjusted. Therefore, the temperature of the exhaust gas GE after exiting the exhaust gas cooler 14 is controlled to the optimum temperature for introduction into the dust collector 8.

By cooling the exhaust gas GE with the exhaust gas cooler 14, the components in the exhaust gas GE are condensed, and ash containing sulfur is attached to the exhaust gas cooler 14. Therefore, the compressed air AC is supplied to the stationary soot blower 16, and the compressed air AC is supplied from the nozzle 16 a to the cooling pipe 1 of the exhaust gas cooler 14.
Spray to No. 5 and remove the attached ash. For this reason,
Even if the temperature of the exhaust gas GE is lowered by the exhaust gas cooler 14 and the ash containing sulfur adheres to the cooling pipe 15, the ash is easily removed, and therefore the risk of corrosion of the exhaust gas cooler 14 is small.

It should be noted that the embodiment of the present invention is not limited to the above-described example of the embodiment, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[0042]

According to the boiler equipment of the present invention, claim 1
In any of 3 to 3, since the temperature of the exhaust gas at the outlet of the air preheater can be increased, the element of the air preheater is not clogged, and the exhaust gas introduced into the dust collector is lowered to a predetermined temperature. Because you can
Without adversely affecting the dust collector, the temperature of the exhaust gas introduced into the dust collector can be accurately controlled in the case of claim 2, and the ash can be prevented from adhering to the exhaust gas cooler in the case of claim 3, etc. The excellent effect of can be achieved.

[Brief description of drawings]

FIG. 1 is a flow chart showing an example of an embodiment of a boiler facility of the present invention.

FIG. 2 is a detailed flow chart of an exhaust gas temperature reduction device used in the boiler equipment of the present invention.

FIG. 3 is a view taken along the line III-III in FIG.

FIG. 4 is a schematic diagram of a conventional boiler facility.

[Explanation of symbols]

 1 Boiler body 6 Exhaust gas duct 7 Regenerative air preheater (air preheater) 8 Dust collector 11 Combustion air duct 14 Exhaust gas cooler 15 Cooling pipe 16 Stationary soot blower (Soot blower) 19 Water circulation pipe (Medium circulation pipe) 20 Water circulation pipe (Medium) Circulation pipe 21 Heat exchanger 25 Water circulation pipe (medium circulation pipe) 28 Flow rate control valve 29 Temperature detector GE Exhaust gas A Combustion air W Water (medium) V Valve opening command signal

Claims (3)

[Claims] 1. An air preheater for preheating combustion air fed to a boiler body through a combustion air duct is provided in an exhaust gas duct through which exhaust gas discharged from the boiler body flows, and the exhaust gas duct is provided in the exhaust gas duct. , Equipped with a dust collector that can introduce the exhaust gas whose temperature has dropped by the air preheater,
An exhaust gas cooler that cools the exhaust gas is installed between the air preheater of the exhaust gas duct and the dust collector, and a heat exchanger that heats the combustion air is provided upstream of the air preheater connection part of the combustion air duct in the air flow direction. A boiler facility, wherein a medium circulation pipe is provided so that a predetermined medium can circulate between the heat exchanger and the exhaust gas cooler. 2. A temperature detector is provided on the exhaust gas cooler outlet side of the exhaust gas duct, and the opening can be adjusted at a required position of the medium circulation pipe based on a valve opening command signal from the temperature detector. The boiler equipment according to claim 1, further comprising a flow control valve. 3. The boiler equipment according to claim 1, wherein a soot blower for removing ash attached to the cooling pipe is provided on the inlet side of the exhaust gas cooler.