JP2014238234A - Regenerative air preheater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regenerative air preheater capable of suppressing wear of a casing inner circumferential surface facing an outer circumference of a sector plate and decreasing the frequency of maintenance.SOLUTION: A gas-side static seal is provided between a center section 5 and a sector plate 6 on a side where exhaust gas flows, an air-side static seal is provided therebetween on a side where fine coal conveyance air flows, and an abrasion proof castable 12 is provided on an inner circumferential surface of a casing 2 facing an outer circumference of the sector plate 6.

Description

  The present invention relates to a regenerative air preheater.

  Generally, in a coal fired boiler plant, regenerative air preheating that preheats pulverized coal transport air (primary air) and combustion air (secondary air) using heat of exhaust gas discharged from the coal fired boiler. A vessel is provided.

  In the regenerative air preheater, a rotor having a heat transfer element made of a metal plate is disposed in a casing having an inner peripheral surface formed in a cylindrical shape so as to be horizontally rotatable around an axis. Center sections extending in the diameter direction of the casing are arranged at the upper and lower portions of the casing. Between the center section and the rotor, a sector plate that divides the side through which the exhaust gas circulates, the side through which the pulverized coal transport air circulates and the side through which the combustion air circulates is supported by the center section. It is fixedly arranged.

  In addition, on the upper and lower surfaces of the rotor, a sector plate that divides the side through which the pulverized coal transport air circulates and the side through which the combustion air circulates is spanned between the center of the center section and the casing. It is fixedly arranged.

  Between the center section and the sector plate, a gas-side static seal is provided on the side through which the exhaust gas flows, an air-side static seal is provided on the side through which the pulverized coal transport air flows, and the air side A fabric seal is provided at the lower end of the static seal.

  Here, since the gas side static seal, the air side static seal, and the fabric seal are provided, the air for conveying pulverized coal having a pressure higher than that of the exhaust gas enters the space between the center section and the sector plate and enters the exhaust gas side. Leakage is kept to a minimum.

  For example, Patent Document 1 shows a general technical level related to the regenerative air preheater as described above.

JP-A-5-264186

  However, with the provision of the gas side static seal, the air side static seal, and the fabric seal, the air for conveying pulverized coal containing high-hardness ash contained in the exhaust gas flows to the outer peripheral side in the radial direction of the rotor. It was way.

  As a result, the inner surface of the casing facing the outer peripheral side of the sector plate is abraded by the ash, resulting in a problem that the maintenance cycle has to be shortened.

  The present invention has been made in view of the above-described conventional problems, and is intended to provide a regenerative air preheater that can reduce the frequency of maintenance by suppressing wear on the inner peripheral surface of the casing facing the outer peripheral side of the sector plate. It is what.

The present invention includes a casing having an inner peripheral surface formed in a cylindrical shape, a rotor rotatably disposed in the casing and having a heat transfer element, and an upper and lower portions of the casing so as to extend in a diameter direction thereof. A center section, and a sector plate fixedly disposed between the center section and the rotor so as to be supported by the center section so as to partition a side through which exhaust gas flows and a side through which pulverized coal transport air flows. In a regenerative air preheater with
Between the center section and the sector plate, a gas side static seal is provided on the side through which the exhaust gas flows, and an air side static seal is provided on the side through which the pulverized coal transport air flows,
The present invention relates to a regenerative air preheater characterized in that a wear-resistant castable is provided on the inner peripheral surface of the casing facing the outer peripheral side of the sector plate.

  In the regenerative air preheater, a purge air pipe for constantly blowing purge air to the gap between the outer peripheral surface of the sector plate and the wear-resistant castable is connected to the upper side of the casing where the wear-resistant castable is provided. It is preferable.

  According to the regenerative air preheater of the present invention, it is possible to achieve an excellent effect that the frequency of maintenance can be reduced by suppressing the wear of the casing inner peripheral surface facing the outer peripheral side of the sector plate.

It is a schematic perspective view which shows the Example of the regenerative air preheater of this invention. It is a top view which shows the sector plate in the Example of the regenerative air preheater of this invention. It is III-III sectional drawing of FIG. It is IV-IV sectional drawing of FIG.

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

  1 to 4 show an embodiment of a regenerative air preheater according to the present invention, wherein 1 is a regenerative air preheater, 2 is a casing having an inner peripheral surface formed in a cylindrical shape, and 3 is a metal plate. A rotor having a thermal element 3 a, and the rotor 3 is disposed inside the casing 2 so as to be horizontally rotatable around a shaft 4.

  Reference numeral 5 denotes a center section extending in the diameter direction of the casing 2, and the center section 5 is disposed at the upper and lower portions of the casing 2.

  6 is a sector plate that divides the side through which the exhaust gas G circulates and the side through which the pulverized coal transport air A1 (primary air) circulates, and 7 the side through which the exhaust gas G circulates and combustion air A2 (secondary air) circulates. It is a sector plate that separates the sides. The sector plates 6 and 7 are fixedly disposed between the center section 5 and the rotor 3 so as to be supported by the center section 5 (see FIG. 2).

  Reference numeral 8 denotes a sector plate that divides the side through which the pulverized coal transport air A1 flows and the side through which the combustion air A2 flows, and the sector plate 8 is located at the center of the center section 5 on the upper and lower surfaces of the rotor 3. It is fixedly arranged so as to be spanned between the part and the casing 2.

  9 is a gas side static seal provided on the side where the exhaust gas G flows between the center section 5 and the sector plate 6, and 10 is pulverized coal conveying air A 1 between the center section 5 and the sector plate 6. It is the air side static seal provided in the distribution | circulation side. Reference numeral 11 denotes a fabric seal provided at the lower end of the air side static seal 10 (see FIG. 4).

  The regenerative air preheater 1 includes pulverized coal transport air A1 supplied to a furnace through a coal fired boiler mill (not shown), and combustion air A2 supplied to the furnace of the coal fired boiler, Heating is performed by the high-temperature exhaust gas G discharged from the furnace.

  In the case of this embodiment, as shown in FIG. 3, the wear-resistant castable 12 is provided on the inner peripheral surface of the casing 2 facing the outer peripheral side of the sector plate 6.

  Further, a purge air pipe 13 for always blowing purge air PA into the gap between the outer peripheral surface of the sector plate 6 and the wear-resistant castable 12 is connected to the upper side of the casing 2 where the wear-resistant castable 12 is provided. It is.

  As shown in FIG. 4, the center section 5 is provided with an ash blow pipe 14 for injecting compressed air for preventing ash from accumulating on the upper surface of the sector plate 6, and the ash blow pipe. An ash discharge pipe 15 that sucks and discharges the ash blown up by the compressed air injected from 14 is disposed.

  Next, the operation of the above embodiment will be described.

  When the rotor 3 rotates, the heat transfer element of the rotor 3 is exposed to the flow of the exhaust gas G discharged from a furnace of a coal fired boiler (not shown) and absorbs heat from the exhaust gas G. Subsequently, the heat transfer element 3a of the rotor 3 is exposed to circulating pulverized coal conveying air A1 and combustion air A2, and the heat absorbed from the exhaust gas G is pulverized coal conveying air A1 and combustion air A2. The pulverized coal carrying air A1 is supplied to the furnace together with the pulverized coal through a mill (not shown), and the combustion air A2 is supplied to the furnace.

  Here, between the center section 5 and the sector plate 6, as shown in FIG. 4, a gas side static seal 9 is provided on the side where the exhaust gas G circulates, and an air side is provided on the side where the pulverized coal transport air A1 is circulated. The static seal 10 is provided with a fabric seal 11 at the lower end of the air side static seal 10. As a result, the pulverized coal carrying air A1 having a pressure higher than that of the exhaust gas G enters the space between the center section 5 and the sector plate 6 and leaks to the exhaust gas G side to a minimum. However, with the provision of the gas side static seal 9, the air side static seal 10, and the fabric seal 11, the pulverized coal transport air A <b> 1 including ash having a high hardness contained in the exhaust gas G is supplied to the rotor 3. There is a history of circulation toward the radially outer periphery.

  Even when the pulverized coal conveying air A1 including ash flows toward the outer peripheral side of the rotor 3 in the radial direction, the wear-resistant castable 12 is formed on the inner peripheral surface of the casing 2 facing the outer peripheral side of the sector plate 6. Therefore, the ash prevents the inner peripheral surface of the casing 2 facing the outer peripheral side of the sector plate 6 from being worn, and the maintenance cycle can be lengthened.

  In addition, since the purge air PA is constantly blown from the purge air pipe 13 into the gap between the outer peripheral surface of the sector plate 6 and the wear-resistant castable 12, the pulverized coal transport air A1 containing ash is resistant to the air. This is effective in mitigating direct impact on the wearable castable 12 and preventing ash from adhering to the wearable castable 12 and accumulating.

  Further, ash may enter between the center section 5 and the sector plate 6 through a gap, but compressed air is injected from the ash blow pipe 14, and the compressed air injected from the ash blow pipe 14 Since the blown up ash is sucked in by the ash discharge pipe 15, the ash is reliably prevented from being deposited on the upper surface of the sector plate 6.

  Thus, the wear of the inner peripheral surface of the casing 2 facing the outer peripheral side of the sector plate 6 can be suppressed, and the frequency of maintenance can be reduced.

  It should be noted that the regenerative air preheater of the present invention is not limited to the above-described embodiments, and it is needless to say that various changes can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Regenerative air preheater 2 Casing 3 Rotor 3a Heat transfer element 4 Shaft 5 Center section 6 Sector plate 9 Gas side static seal 10 Air side static seal 12 Wear-resistant castable 13 Purge air piping G Exhaust gas A1 Air for pulverized coal conveyance (primary air) )
A2 Combustion air (secondary air)
PA purge air

Claims (2)

A casing having an inner peripheral surface formed in a cylindrical shape, a rotor rotatably disposed in the casing and having a heat transfer element, and a center section disposed in the upper and lower portions of the casing so as to extend in the diameter direction thereof And a regenerator provided between the center section and the rotor, and a sector plate fixedly arranged in a form supported by the center section so as to partition the side through which the exhaust gas flows and the side through which the pulverized coal transport air flows. In the air preheater,
Between the center section and the sector plate, a gas side static seal is provided on the side through which the exhaust gas flows, and an air side static seal is provided on the side through which the pulverized coal transport air flows,
A regenerative air preheater characterized in that a wear-resistant castable is provided on the inner peripheral surface of the casing facing the outer peripheral side of the sector plate.   The regenerative air preheating according to claim 1, wherein a purge air pipe for constantly blowing purge air to a gap between the outer peripheral surface of the sector plate and the wear resistant castable is connected to an upper side of the casing where the wear resistant castable is provided. vessel.

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