JP5973517B2 - Seal mechanism for air preheater - Google Patents

Description

  The present invention relates to a seal mechanism for an air preheater that preheats combustion air to be fed into a boiler.

  An air preheater is a device that heats fuel air by exchanging heat between high-temperature exhaust gas discharged from the boiler and low-temperature fuel air. Generally, in large boiler facilities, a regenerative air preheater is used. (For example, refer to Patent Document 1). In the rotary regenerative air preheater, for example, a rotor filled with a heat exchange element (heat transfer body) rotates while being accommodated in a rotor housing. Further, sector plates are provided on both end faces of the rotor housing so as to divide the rotor into two, and an exhaust gas passage and a combustion air passage are formed. And the heat exchange element heated with exhaust gas moves to the combustion air side with rotation of a rotor, and heat exchange that heats combustion air is repeated.

  Thus, since the rotor rotates, the rotary regenerative air preheater is provided with a seal mechanism for preventing and suppressing leakage of gas and air from the end face of the rotor. That is, as shown in FIG. 4A, between the rotor tire 102 provided on the low temperature side end surface (lower surface) of the rotor 101 and the low temperature side sealing bar 103, and the high temperature side end surface (upper surface) of the rotor 101. A CCS (Circam Carbon Seal) unit 110 is disposed between a sealing bar 104 provided on the high temperature side and a high-temperature-side reinforcement plate 105.

  The CCS unit 110 has a carbon body 111 having a rectangular cross section, a lower surface thereof disposed in contact with the sealing bars 103 and 104, and a stainless steel carbon cover 112 that covers both side surfaces and the upper surface of the carbon body 111 by bolts 113. Attached to the carbon body 111. Further, a carbon holder 114 having an inverted U-shaped cross section is disposed so as to cover and support the upper surface and the upper side surface of the carbon cover 112, and between the both side surfaces of the carbon cover 112 and the carbon holder 114, A side gap S11 is provided, and a lower end gap S12 is provided between the carbon holder 114 and the sealing bars 103, 104.

  Along with the rotor 101, the sealing bar 104, the rotor tire 102, and the CCS unit 110 on the low temperature side rotate, and the carbon body 111 is always in contact with the sealing bars 103, 104, thereby preventing leakage of gas and air. It is to prevent and suppress.

JP 2010-065929 A

  By the way, in the conventional sealing mechanism, since the carbon body 111 is fixed to the carbon cover 112 by the bolt 113, uneven wear and abnormal wear of the carbon body 111 occur. That is, since the side surface gap S11 exists, for example, the carbon cover 112 tilts or slightly vibrates in the carbon holder 114, and the carbon body 111 also tilts or slightly vibrates accordingly, and the carbon body 111 is unevenly worn. Or abnormal wear.

  Further, when the carbon cover 112 and the carbon holder 114 are fixed at the time of the cold can (due to entrapment of foreign matter, deformation of the carbon holder 114 over time, distortion due to the thermal effect, etc.), the sealing is performed together with the turn-down of the rotor 101 at the time of the heat can. The bar 103 is pushed in, and the carbon body 111 is first worn, and the carbon cover 112 may be cracked / damaged and deformed. As a result, the carbon body 111 had to be replaced early.

  Further, the carbon body 111 and the carbon cover 112 are integrated, and not only the carbon body 111 is worn, but the carbon body 111 and the carbon cover 112 are simultaneously worn and worn as shown in FIG. 4B. It was. When wear progresses and the carbon cover 112 becomes smaller and lower, the carbon body 111 and the carbon cover 112 may come out from the lower end gap S12. In such a case, a trip of the air preheater or the like occurs, which greatly affects the power generation unit. give. For this reason, it is necessary to replace the carbon body 111 and the carbon cover 112 at an early stage before the carbon body 111 and the carbon cover 112 come out of the lower end gap S12.

  In addition, since the stainless steel carbon cover 112 always wears in contact with the sealing bars 103 and 104, the sealing bars 103 and 104 are damaged and worn. Therefore, the sealing bars 103 and 104 must be periodically replaced. became.

  Accordingly, an object of the present invention is to provide a seal mechanism for an air preheater that can suppress the frequency of replacement of components.

In order to solve the above-mentioned problems, the invention of claim 1 performs heat exchange between exhaust gas from the boiler and fuel air through the heat exchange element as the rotor filled with the heat exchange element rotates. A sealing mechanism of an air preheater for heating the air for fuel, a carbon body for ensuring airtightness with a lower surface contacting a sealing bar, and a carbon cover covering both side surfaces and an upper surface of the carbon body; A carbon holder that covers and supports an upper surface of the carbon cover and upper portions of both side surfaces, and a lower end gap provided between the carbon cover and the carbon body, the carbon body being movable with respect to the carbon cover freely in the and lower surface adapted to move relative to the carbon cover by abrasion, the carbon cover, even after wear of the carbon body, A state where the upper part of both sides is covered maintained by serial carbon holder, and wherein the.

  According to the invention of claim 1, since the carbon body is movable with respect to the carbon cover, for example, even if the carbon cover tilts or slightly vibrates in the carbon holder, the carbon body does not tilt (tilt). Etc.), and uneven wear and abnormal wear of the carbon body are suppressed. As a result, it is possible to suppress the replacement frequency of the carbon body.

  Further, when the lower surface of the carbon body is worn, the carbon body moves relative to the carbon cover, so that the carbon cover is not worn or consumed. For this reason, the carbon body and the carbon cover do not come out of the carbon holder, and the replacement frequency of the carbon body and the carbon cover can be suppressed.

  Furthermore, since the carbon cover is not worn or consumed, the damage and wear of the sealing bar by the carbon cover can be reduced or suppressed, and the replacement frequency of the sealing bar can be suppressed. In this way, it is possible to suppress the replacement frequency of the carbon body, the carbon cover, and the sealing bar, which are component parts.

It is sectional drawing which shows the sealing mechanism of the air preheater which concerns on embodiment of this invention. It is sectional drawing which shows the state with which the carbon body of the seal mechanism of FIG. 1 was worn. It is a section perspective view showing a part of rotation regenerative air preheater concerning an embodiment of this invention. It is sectional drawing (a) which shows the state in which the carbon body of the conventional sealing mechanism is not worn, and sectional drawing (b) which shows the state in which the carbon body was worn.

  The present invention will be described below based on the illustrated embodiments.

  1 to 3 show an embodiment of the present invention, and FIG. 1 is a sectional view showing a seal mechanism (hereinafter referred to as “seal mechanism”) 1 of an air preheater according to this embodiment. The seal mechanism 1 is a mechanism for preventing / suppressing leakage of air / gas from the end face of the rotor 11 of the rotary regenerative air preheater (air preheater) 10.

  Here, the rotary regenerative air preheater 10 is a device that heats the fuel air by exchanging heat between the high-temperature exhaust gas discharged from the boiler and the low-temperature fuel air, and excluding the seal mechanism 1, It has the same structure as a conventional off-the-shelf / existing air preheater. That is, as shown in FIG. 3, a cylindrical rotor 11 is filled with a heat exchange element (not shown) as a heat transfer body / heat medium so that the rotor 11 rotates about the rotor post 12 as an axis. It has become. In addition, sector plates 14 are provided on both end faces of the rotor housing 13 that accommodates the rotor 11 so as to divide the rotor 11 into two, and a flow path through which exhaust gas passes and a flow path through which combustion air passes are formed. ing.

  The heat exchange element heated by passing the exhaust gas moves to the combustion air side as the rotor 11 rotates, and the combustion air is heated by passing the combustion air through the heat exchange element. At the same time, the heat exchange element through which the combustion air has passed is cooled. In this way, the heat exchange cycle of heating the fuel air by exchanging heat between the exhaust gas from the boiler and the fuel air via the heat exchange element is repeated. In FIG. 3, reference numeral 15 is a diaphragm plate, reference numeral 16 is a floating radial seal (FRS), reference numeral 17 is a holding strip, reference numeral 18 is a low temperature side radial seal, and the lower side in FIG. 3 is the low temperature side (inflow of combustion air). The upper side is the high temperature side (combustion air outflow side).

  The seal mechanism 1 is provided on the end face side of the rotor 11 of the rotary regenerative air preheater 10. The seal mechanism 1 includes a plurality of CCS (circum carbon seal) units 2 disposed on both end surfaces of the rotor 11.

  That is, as shown in FIGS. 1 and 3, the rotor tire 31 is disposed on the low temperature side end surface (lower surface) of the rotor 11, and the low temperature side sealing bar 32 is disposed on the low temperature side end surface 131 of the rotor housing 13, A plurality of CCS units 2 are disposed between the rotor tire 31 and the low temperature side sealing bar 32. Similarly, a high temperature side sealing bar 41 is disposed on the high temperature side end surface (upper surface) of the rotor 11, and a rain forcing plate 42 is disposed below the high temperature side end surface 132 of the rotor housing 13. A plurality of CCS units 2 are arranged between the forcing plate 42.

  Each CCS unit 2 includes a carbon body 5, a carbon cover 6, and a carbon holder 7.

  The carbon body 5 is made of carbon / carbon powder and is a block body having a rectangular cross section, and its lower surface 5a is disposed in contact with the low temperature side sealing bar 32 or the high temperature side sealing bar 41. Thereby, as will be described later, airtightness is ensured (gas leakage is suppressed).

  The carbon cover 6 is made of stainless steel having an inverted U-shaped cross section, and is attached to the carbon body 5 so as to cover both side surfaces and the upper surface of the carbon body 5. Here, the length of the side surface of the carbon cover 6 is set to the same length as the side surface of the new carbon body 5 that is not worn, and covers the entire side surface of the carbon body 5. That is, both the side surfaces and the upper surface of the new carbon body 5 are in contact with the inner surface of the carbon cover 6 over the entire surface. The carbon cover 6 has a role of preventing the carbon body 5 from being worn and damaged (ash erosion) by ash flow coal ash or the like.

  The carbon holder 7 is a cover that has an inverted U-shaped cross section and supports the upper portion of the carbon cover 6. Specifically, on the low temperature side, the upper surface is fixed to the rotor housing 13, and on the high temperature side, the upper surface is fixed to the reinforcement plate 42 and covers and supports the entire upper surface of the carbon cover 6 and the upper portions of both side surfaces. It is arranged like this. In addition, side gaps S1 are provided between both side surfaces of the carbon cover 6 and the inner surface of the carbon holder 7, and lower end edges of the both side surfaces of the carbon holder 7 and the low temperature side sealing bar 32 or the high temperature side sealing bar 41. A lower end gap S2 is provided between them.

  The high temperature side sealing bar 41, the rotor tire 31 and the low temperature side CCS unit 2 rotate together with the rotor 11, and the carbon body 5 always contacts the low temperature side sealing bar 32 or the high temperature side sealing bar 41. Sealing prevents or suppresses leakage of gas (including exhaust gas and fuel air).

  In such a CCS unit 2, the carbon body 5 is movable (free) with respect to the carbon cover 6, and moves with respect to the carbon cover 6 when the lower surface 5 a is worn. That is, the carbon body 5 is not fixed to the carbon cover 6 just covered with the carbon cover 6, and is movable (movable) within the carbon cover 6. When the lower surface 5a is worn due to contact with the sealing bars 32, 41, as shown in FIG. 2, the carbon body 5 moves in the carbon cover 6 as the lower surface 5a is consumed, and the sealing bars 32, 41 side To proceed to.

  Further, since the carbon cover 6 is not fixed integrally with the carbon body 5, the end faces (side surfaces) of the carbon cover 6 on the sealing bars 32 and 41 side are not worn with the wear of the carbon body 5. Or less wear. That is, only the carbon body 5 is largely worn and moves in the carbon cover 6.

  In the sealing mechanism 1 having such a configuration, when the rotating part rotates including the rotor 11, the high temperature side sealing bar 41, the rotor tire 31, and the low temperature side CCS unit 2, the carbon body 5 of the low temperature side CCS unit 2 and The low temperature side sealing bar 32 and the carbon body 5 of the high temperature side CCS unit 2 and the high temperature side sealing bar 41 move and slide relative to each other while always in contact with each other. As a result, leakage of exhaust gas and fuel air is prevented and suppressed, and the carbon body 5 is worn and consumed from the lower surface 5a side as time passes. At this time, the carbon cover 6 does not wear or wears little. As shown in FIG. 2, only the carbon body 5 moves toward the sealing bars 32 and 41 in the carbon cover 6 as the lower surface 5 a is consumed.

  As described above, according to the seal mechanism 1, the carbon body 5 is movable with respect to the carbon cover 6. For example, even if the carbon cover 6 tilts or slightly vibrates in the carbon holder 7, The body 5 is not inclined (the inclination is small), and uneven wear and abnormal wear of the carbon body 5 are suppressed. As a result, the replacement frequency of the carbon body 5 can be suppressed.

  Further, even if the lower surface 5a of the carbon body 5 is worn, the end surfaces of the carbon cover 6 on the sealing bars 32 and 41 side are not worn or little worn. For this reason, the carbon body 5 and the carbon cover 6 do not come out of the carbon holder 7. In other words, since the carbon cover 6 is suppressed from becoming small and low due to wear, the carbon cover 6 containing the carbon body 5 does not come out of the lower end gap S2, and the carbon body 5 and the carbon cover 6 are replaced at an early stage. There is no need. In particular, even if the height of the carbon body 5 is equal to or lower than the lower end gap S2, the carbon cover 6 that accommodates the carbon body 5 does not come out, and therefore it is not necessary to replace the carbon body 5. In this way, the replacement frequency of the carbon body 5 and the carbon cover 6 can be suppressed.

  Further, since the carbon cover 6 is not worn or consumed, the damage and wear of the sealing bars 32 and 41 due to the carbon cover 6 are reduced and suppressed, and the replacement frequency of the sealing bars 32 and 41 can be suppressed. That is, the fact that the carbon cover 6 is not worn or consumed means that the frictional force against the sealing bars 32 and 41 is small, so that the damage and wear of the sealing bars 32 and 41 are reduced, and the replacement frequency of the sealing bars 32 and 41 is suppressed. Is possible.

  In this manner, it is possible to suppress the replacement frequency of the carbon body 5, the carbon cover 6, and the sealing bars 32 and 41, which are constituent parts. As a result, it is possible to reduce parts costs, replacement work costs, and the like, and it is possible to stably operate the rotary regenerative air preheater 10. Furthermore, by reducing the amount of wear, it is possible to manage the flatness of the sealing bars 32 and 41, the rotor tire 31 and the reinforcement plate 42 at a low level, that is, to reduce the management standard.

  Moreover, since it is only necessary to make the carbon body 5 movable with respect to the carbon cover 6, it can be easily applied to the existing and ready-made rotary regenerative air preheater 10.

  Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, a pressing means such as a pressure plate or a spring may be provided between the upper surface of the carbon body 5 and the upper plate portion of the carbon cover 6 so that only the carbon body 5 is always pressed against the sealing bars 32 and 41 side. .

1 Sealing Mechanism 2 CCS Unit 31 Rotor Tire 32 Low Temperature Side Sealing Bar (Sealing Bar)
41 High-temperature side sealing bar (ceiling bar)
42 Reinforcing plate 5 Carbon body 5a Lower surface 6 Carbon cover 7 Carbon holder 10 Regenerative air preheater (air preheater)
11 Rotor 12 Rotor post 13 Rotor housing 14 Sector plate

Claims (1)

A seal mechanism of an air preheater that heats the fuel air by exchanging heat between the exhaust gas from the boiler and the fuel air through the heat exchange element as the rotor filled with the heat exchange element rotates. There,
A carbon body for ensuring the airtightness when the lower surface is in contact with the sealing bar;
A carbon cover covering both side surfaces and an upper surface of the carbon body;
A carbon holder that covers and supports the upper surface of the carbon cover and the upper part of both side surfaces, and a lower end gap is provided between the sealing bar, and
With
The carbon body is freely movable relative to the carbon cover, the and the lower surface is adapted to move relative to the carbon cover by abrasion, the carbon cover, even after wear of the carbon body, the The state where the upper part of both sides is covered by the carbon holder is maintained ,
An air preheater sealing mechanism.

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