JPH09280760A - Rotemulle type air preheater having hot primary air fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve damage of a fan by a method wherein an air output hood on the low temperature side is provided to partition the low temperature side of air on the output side in an air hood on the output side, an air output port on the low temperature side communicated with the hood is connected to a primary air duct, and an air outlet on the high temperature side is connected to a secondary air duct. SOLUTION: An air output hood 28 on the low temperature side is formed in such a manner to be outputted in a way that the low temperature side B of air on the output side in an air hood 6 on the output side is partitioned. An air output port on the low temperature side communicating with a hood 28 is formed on the axis side of a shaft 10 of the air hood 6 on the output side and an air output port on the high temperature side is concentrically formed in the outside of an air output port on the low temperature side. Further, a secondary air output duct connected to the air output port on the high temperature side. A primary air output duct connected to the air output port on the low temperature side is connected to a primary air duct having a hot primary air fan. This constitution feeds primary air having a low dust concentration to the fan, and relieves damage of the fan.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to supplying a part of air after heating by a low temule air preheater to a pulverized coal mill as a primary air through a hot primary air fan. The present invention relates to a rotoremure type air preheater equipped with a primary air fan.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a pulverized coal fired boiler equipped with a rotemuhle type air preheater, in which 1 is a pulverized coal fired boiler and 2 is a hot primary air fan 20.
Is a system equipped with a rotoremure type air preheater, and the rotoremure type air preheater 2 is, as shown in FIGS. 5 and 6, provided on both sides (left and right sides in FIG. 5) of the disc-shaped heat exchange element 3. , An inlet side air hood 5 and an outlet side air having a butterfly shape (FIG. 6) sandwiching the heat exchange element 3 so as to conduct the air 4 in the same required angle range around the center of the heat exchange element 3. The hood 6 is arranged so as to face each other and surrounds the inlet air hood 5 and the outlet air hood 6 so that the high temperature exhaust gas 7 is conducted in the remaining angular range.
An inlet-side fixed exhaust gas hood 8 and an outlet-side fixed exhaust gas hood 9 are provided so as to sandwich either the inlet-side or outlet-side air hoods 5 and 6 or the heat exchange element 3 to rotate.
The illustrated case shows a case in which the inlet air hood 5 and the outlet air hood 6 connected by the shaft 10 are integrally rotated. In the figure, C is a color seal of the rotating part.

The inlet side fixed exhaust gas hood 8 and the outlet side fixed exhaust gas hood 9 are the exhaust gas duct 11 of the pulverized coal burning boiler 1.
And an inlet air duct 12 and an outlet air hood 6 that are rotatably connected to the inlet air hood 5.
An outlet air duct 13 that is rotatably connected to the outside is guided to the outside across the inlet fixed exhaust gas hood 8 and the outlet fixed exhaust gas hood 9.

The heat exchange element 3 is configured such that a large number of corrugated steel sheets are laminated with a gap between each other and the hot exhaust gas 7 and the air 4 are sequentially flowed into the gap for heat exchange.

The low temule air preheater 2 shown in FIGS. 5 and 6 shows a horizontal type in which the shaft 10 is installed horizontally, but it is a vertical type in which the shaft 10 is installed vertically. Is also used.

The exhaust gas 7 from the pulverized coal-fired boiler 1 shown in FIG. 4 is guided to the heat exchange element 3 by the exhaust gas duct 11 via the inlet side fixed exhaust gas hood 8 shown in FIG. 5 to heat the heat exchange element 3. After that, the induction fan 14 (I
DF) and is guided to the chimney 15.

Further, the pushing fan 16 (FD
The air 4 supplied from F) is the inlet side air duct 12
5 is guided to the heat exchange element 3 through the inlet side air hood 5 of FIG. 5 to cool the heat exchange element 3 and at the same time, itself is heated and then the outlet side air hood 6 becomes high temperature outlet side air 4 ′. The secondary air 4a is supplied to the burner 18 of the pulverized coal burning boiler 1 via the secondary air duct 17.

On the other hand, a part of the heated outlet air 4'from the outlet air duct 13 is used as the primary air 4b by the primary air duct 19 and the hot primary air fan 2
It is adapted to be supplied to the pulverized coal mill 21 via 0.

Further, as shown in FIG. 4, a part of the low temperature air 4 from the forced draft fan 16 passes through the bypass duct 22 which does not pass through the low temule air preheater 2 and the hot primary air fan 20. The temperature of the primary air 4b is adjusted by adjusting the temperature adjusting dampers 23 and 24 provided on the upstream side of the hot primary air fan 20 and the bypass duct 22. The side temperature can be maintained at the set temperature.

The pulverized coal which is supplied with the coal 26 from the coal supply device 25 and pulverized by the pulverized coal mill 21 is conveyed by the primary air 4b to the pulverized coal burning boiler 1 through the pulverized coal pipe 27 and the burner 18 Is combusted together with the secondary air 4a.

In the above-mentioned low temule air preheater 2, the slowly rotating heat exchange element 3 is heated by the high temperature exhaust gas 7 introduced from the inlet side fixed exhaust gas hood 8, and then the heat exchange element 3 is heated. Air 4 from the inlet side air hood 5 is supplied to the heated portion of the outlet side to become heated outlet side air 4 ', and the outlet side air 4'is led out via the outlet side air hood 6 and the outlet side air duct 13. Most of it is supplied to the burner 18 of the pulverized coal burning boiler 1 as the secondary air 4a by the secondary air duct 17.

Further, a part of the heated outlet air 4'is taken out by a primary air duct 19 provided in a branch of the outlet air duct 13 and is then taken by a hot primary air fan 20 into the primary air 4b. As pulverized coal mill 21
Is supplied to.

In the rotemuhle type air preheater 2,
In FIG. 5, the temperature at the position near the front wall 6a where the outlet air hood 6 rotates is slightly higher than the average temperature of the outlet air 4'derived from the outlet air hood 6 becomes the high temperature side A. On the contrary, the temperature at the position near the rear wall 6b is on the low temperature side B which is slightly lower.

[0014]

However, in the low temule type air preheater 2 including the conventional hot primary air fan 20 shown in FIGS. 4 to 6, the outlet air duct 13 to the secondary air duct are used. Since the 17 and the primary air duct 19 are provided so as to be branched, the following problems occur.

That is, the rotemuhle type air preheater 2 is
Since heat is exchanged by passing the exhaust gas 7 and then the air 4 to the heat exchange element 3, when the air 4 passes after the exhaust gas 7 passes, the heat exchange element 3 stays in the heat exchange element 3. The dust in the exhaust gas 7 is brought to the air 4 side by taking in the exhaust gas 7 being discharged to the air 4 side, and the dust attached to the heat exchange element 3 by the passage of the exhaust gas 7 passes the air 4 It is removed by and is brought into the air 4.

At this time, since the high temperature side A in the outlet air hood 6 is a portion where the outlet air 4'is led out through the heat exchange element 3 portion immediately after the exhaust gas 7 has passed, The dust concentration in the outlet air 4 ′ on the high temperature side A is extremely high, and the dust on the heat exchange element 3 is removed by the outlet air 4 ′ led to the high temperature side A. As a result, the closer the temperature is to the low temperature side B, the lower the dust concentration in the outlet air 4 ', and the dust concentration in the outlet air 4'on the low temperature side B is extremely low.

However, in the conventional device, the outlet air 4'having a high dust concentration and the outlet air 4'having a low dust concentration are mixed in the outlet air hood 6 to be discharged, so that the outlet air hood 6 is discharged. Outlet air 4'outlet from the side air duct 13
Has a considerably high dust concentration. Conventionally, the outlet side air 4 ′ having such a high dust concentration is branched as it is and the primary air duct 19 is used to supply the hot primary air fan 20.
Since the hot primary air fan 20 is worn by the dust, the life of the expensive hot primary air fan 20 is remarkably shortened, and the hot primary air fan 20 needs to be replaced in a short period of time, resulting in high maintenance cost. Was causing the problem.

The present invention has been made in view of the above circumstances, and reduces the dust concentration in the primary air supplied to the primary air duct equipped with the hot primary air fan to reduce the wear of the hot primary air fan. Therefore, it is an object of the present invention to provide a low temule air preheater equipped with a hot primary air fan whose life is extended.

[0019]

SUMMARY OF THE INVENTION A low temule air preheater equipped with a hot primary air fan according to the present invention comprises:
A disc-shaped heat exchange element and an inlet side air hood and an outlet side air hood sandwiching the heat exchange element so as to conduct air in the same required angle range centered on the center of the heat exchange element are provided. The inlet side fixed air exhaust hood and outlet side air hood are surrounded, and the inlet side fixed exhaust gas hood and the outlet side fixed exhaust gas hood are provided with a heat exchange element sandwiched between them so that high temperature exhaust gas is conducted to the remaining angular range. The inlet side air hood and the heat exchange element provided on the outlet side air hood are rotated, and the outlet side air in the outlet side air hood is connected to a pulverized coal mill via a hot primary air fan. Rotemure air with a hot primary air fan intended to feed the primary air duct and a secondary air duct connected to the burner of a pulverized coal fired boiler A low-temperature side air outlet hood that divides the low-temperature side of the outlet-side air inside the outlet-side air hood, and the low-temperature side air outlet communicating with the low-temperature side air outlet hood is the primary air duct. And a high temperature side air outlet connected to the outlet air hood and connected to the secondary air duct.

In the present invention, a low temperature side air extraction hood is provided for partitioning the low temperature side of the discharge side air inside the discharge side air hood, and only the discharge side air having a low dust concentration in the low temperature side air extraction hood is divided. By taking it out and supplying it to the primary air duct provided with the hot primary air fan, the wear of the hot primary air fan due to dust can be reduced and the life can be extended.

[0021]

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

FIGS. 1 to 3 show an example of an embodiment for carrying out the present invention applied to a low temule type air preheater equipped with the conventional hot primary air fan shown in FIGS. 4 to 6. Those given the same reference numeral represent the same thing.

As shown in FIG. 1, an inlet side air hood 5 and an outlet side air hood 6 and an inlet side fixed exhaust gas hood 8 and an outlet side fixed exhaust gas hood 9 are provided so as to sandwich the disk-shaped heat exchange element 3. In the low temule air preheater 2 which is present, a low temperature side air extraction hood 28 is formed to partition and take out the low temperature side B of the outlet side air 4 ′ inside the outlet side air hood 6, and the low temperature side air extraction is performed. A low temperature side air outlet 29 communicating with the hood 28 is provided on the shaft center side of the shaft 10 of the outlet side air hood 6 as shown in FIGS. 1 and 3, and an outlet side other than the low temperature side air outlet hood 28. A high temperature side air outlet 30 communicating with the inside of the air hood 6 is concentrically provided outside the low temperature side air outlet 29.

Further, the secondary air outlet duct 31 rotatably connected to the high temperature side air outlet 30 is led out to the outside across the inlet side fixed exhaust gas hood 8 and the secondary air duct 17 is provided.
And a rotatably connected primary air outlet duct 32 to the low temperature side air outlet 29, after guiding the secondary air outlet duct 31 into the secondary air outlet duct 31.
To the outside and connected to the primary air duct 19 equipped with the hot primary air fan 20.

As described with reference to FIGS. 5 and 6, in the low temule air preheater 2, heat exchange is performed by passing exhaust gas 7 to the heat exchange element 3 and then passing air 4. Therefore, since the exhaust gas 7 accumulated in the heat exchange element 3 is taken into the air 4 side, the dust in the exhaust gas 7 is brought into the air 4 side, and the flow of the exhaust gas 7 causes the heat exchange element 3 to flow.
The dust adhering to is removed by the flow of the air 4 and is carried into the air 4. Further, the high temperature side A in the outlet air hood 6 has the heat exchange element 3 portion immediately after the exhaust gas 7 has passed therethrough. Since the outlet side air 4 ′ is discharged through the outlet side air 4 ′, the dust concentration in the outlet side air 4 ′ on the high temperature side A is very high.
The heat exchange element 3 is discharged by the outlet air 4 '
The dust concentration in the outlet air 4'decreases as the temperature gets closer to the low temperature side B because the dust is removed.
The dust concentration in the outlet air 4'on the low temperature side B is extremely low.

Therefore, as shown in the above embodiment, when the low temperature side air extraction hood 28 for partitioning the low temperature side B of the outlet side air 4'in the outlet side air hood 6 is provided, the low temperature side B is provided.
It is possible to separately take out only the outlet air 4 ′ having a low dust concentration, and thus the outlet air 4 ′ having a low dust concentration can be taken out through the low temperature side air outlet 29 and the primary air outlet duct 32. When the duct 19 is supplied with the primary air 4b, the hot primary air fan 20 connected to the primary air duct 19 is supplied with the primary air 4b having a low dust concentration. The wear is reduced and the life of the hot primary air fan 20 is extended.

Further, the outlet air 4'taken out from the high temperature side A by the outlet air hood 6 has a high dust concentration, and the outlet air 4'having a high dust concentration is the high temperature side air outlet. Even if the secondary air 4a is supplied to the secondary air duct 17 via the secondary air outlet duct 31 and the secondary air outlet duct 31, the secondary air 4a is directly guided to the burner 18 of the pulverized coal burning boiler 1 without any problem. Will not occur.

[0028]

According to the rotemuhle type air preheater equipped with the hot primary air fan of the present invention, the low temperature side air extraction hood for partitioning the low temperature side of the outlet side air inside the outlet side air hood is provided. Only the outlet side air with low dust concentration in the low temperature side air outlet hood is taken out separately and supplied to the primary air duct equipped with the hot primary air fan, so the wear of the hot primary air fan due to dust is reduced. The excellent effect that the life can be extended can be exhibited.

[Brief description of drawings]

FIG. 1 is a cut-away side view showing an example of an embodiment of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a view in the direction of arrows III-III in FIG. 1;

FIG. 4 is a system diagram showing an example of a pulverized coal burning boiler equipped with a low temule air preheater of a system equipped with a hot primary air fan.

FIG. 5 is a cut side view showing an example of a conventional low temule air preheater having a hot primary air fan.

6 is a VI-VI direction arrow view of FIG.

[Explanation of symbols]

 1 Pulverized coal-fired boiler 2 Rotemure type air preheater 3 Heat exchange element 4 Air 4'Outlet air 5 Inlet air hood 6 Outlet air hood 7 Exhaust gas 8 Inlet fixed exhaust gas hood 9 Outlet fixed exhaust gas hood 17 Secondary Air duct 18 Burner 19 Primary air duct 20 Hot primary air fan 21 Pulverized coal mill 28 Low temperature side air extraction hood 29 Low temperature side air outlet 30 High temperature side air outlet B B Low temperature side

Claims (1)

[Claims] 1. A disc-shaped heat exchange element, and an inlet side air hood and an outlet side air hood sandwiching the heat exchange element so as to conduct air in the same required angle range centered on the center of the heat exchange element. The inlet side air hood and the outlet side air hood are surrounded, and an inlet side fixed exhaust gas hood and an outlet side fixed exhaust gas hood are provided with a heat exchange element sandwiched therebetween so as to conduct high temperature exhaust gas to the remaining angular range, One of the inlet side and outlet side air hoods and the heat exchange element provided on both sides of the heat exchange element is rotated, and the outlet side air in the outlet side air hood is pulverized coal through a hot primary air fan. Rotemi with a hot primary air fan intended to feed a primary air duct connected to the mill and a secondary air duct connected to the burner of a pulverized coal burning boiler In the Thule type air preheater, a low temperature side air extraction hood that partitions the low temperature side of the output side air inside the output side air hood is formed, and the low temperature side air outlet communicating with the low temperature side air extraction hood is A low temule air preheater having a hot primary air fan, wherein a high temperature side air outlet connected to a primary air duct and communicating with the outlet air hood is connected to the secondary air duct.