JPH0791277A - Exhaust dust - Google Patents

Abstract

PURPOSE:To prevent chattering of an explosion-proof door by slantly standing the explosion-proof door upstream, and by opening the door through a process of putting it down downward by a specific dynamic pressure in an exhaust duct wherein a bypass duct is communicated with a bypass chimny through the explosion-proof door to be opened by dynamic pressure of exhaust gas. CONSTITUTION:When a gas turbine of a composite electric power plant is individually operated, an outlet damper 5a of an exhaust duct 6 is closed after opening an inlet damper 8a of a bypass chimny 8 in the exhaust duct 6. A bypass duct 9 provided with an explosionproof door 7 is arranged in order to prevent abnormal boost pressure from being generated in the exhaust duct 6 even if both dampers 8a, 5a are respectively closed. In this case, the explosion- proof door 7 is stood against an inlet part of the bypass duct 9 in the exhaust duct 6 and slantly arranged in the direction to oppose horizontal load F0 by dynamic pressure pd of exhaust gas. The explosion-proof door 7 is pressed and opened at once when the load F0 exceeding the moment M for always closing the explosion-proof door 7 by own weight F is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust duct applied to a combined power generation plant including an exhaust gas boiler and a gas turbine.

[0002]

1 and 2 are explanatory views of a conventional exhaust duct used in a combined power generation plant of an exhaust gas boiler and a gas turbine. In the figure, a combined power generation plant of an exhaust gas boiler and a gas turbine is generally shown as a compressor 1
The gas turbine 2 is rotated by using the high-temperature high-pressure gas generated by burning the fuel with the high-pressure air compressed by the gas turbine 2. The gas turbine 2 drives the generator 3 to generate electricity and is discharged from the gas turbine 2. The exhaust gas boiler 5 uses the exhaust gas to generate steam, and the steam is used to rotate the steam turbine 4 that drives the generator 3 to generate electric power.

When operating the gas turbine 2 alone in such a combined cycle power plant, first, the damper 8a at the inlet of the bypass chimney 8 of the exhaust duct 6 provided between the gas turbine 2 and the exhaust gas boiler 5 is installed. Open operation,
Next, the damper 5a on the outlet side of the exhaust duct 6 for supplying air to the exhaust gas boiler 5 is closed. At this time, even if the switching operation between the dampers 5a and 8a fails and both dampers 5a and 8a are closed, the abnormal pressure increase in the exhaust duct 6 does not occur so that the abnormal pressure increase in the exhaust duct 6 does not occur. As a preventive measure (explosion-proof measure), a bypass duct 9 of a bypass chimney 8 having an explosion-proof door 7 is installed.

[0004]

In the conventional exhaust duct as described above, the explosion-proof door 7 is installed in the bypass duct 9 of the bypass chimney 8 so as to open and close in the vertical direction, and the gas turbine 2 operates independently. In the case of performing the above, a force to push up the explosion-proof door 7 acts by receiving a load in the vertical direction due to the dynamic pressure of the exhaust gas due to the discharge of the exhaust gas from the bypass chimney 8. Since the pressure of the exhaust gas in the exhaust duct 6 is unstable when the exhaust gas is released,
The vertical load due to the dynamic pressure of the exhaust gas may fluctuate, and the explosion-proof door 7 may cause a chattering phenomenon in which transient opening and closing are repeated. Here, the load F of the explosion-proof door 7 and the vertical load F ₀ due to the dynamic pressure of the exhaust gas are expressed by the following equations.

[0005] _{F 0 = Pd · A Pd =} γ · V 2 / 2g A = π · d 2/4 However, F is the own weight of the anti爆扉7, F ₀ is the load in the vertical direction by the dynamic pressure of the exhaust gas, Pd is Dynamic pressure, A is the flow passage cross-sectional area of the exhaust duct 6, γ is the specific gravity of the exhaust gas, V is the flow velocity of the exhaust gas, g is the acceleration of gravity, π is the circular constant, and d is the diameter of the duct.

When the chattering of the explosion-proof door 7 is too large, a counterweight (weight for adjustment) is attached to the explosion-proof door 7 to prevent the load of the explosion-proof door 7 from the vertical load due to the dynamic pressure of exhaust gas. However, it is not a fundamental preventive measure, and the surrounding environment is affected by noise caused by the explosion-proof door 7 being damaged by chattering or the collision between the explosion-proof door 7 and the seat surface. There are problems such as being harmed.

[0007]

The exhaust duct according to the present invention is intended to solve the above-mentioned problems, and is connected to the bypass chimney through an exhaust bypass chimney and an explosion-proof door that opens at a predetermined dynamic pressure of the exhaust. In an exhaust duct provided with a bypass duct that conducts, the explosion-proof door is vertically installed so as to be inclined toward the upstream side, closes the bypass duct, and collapses and opens downstream with a predetermined dynamic pressure of exhaust.

[0008]

That is, in the exhaust duct according to the present invention, the explosion-proof door in the exhaust duct is provided with the bypass chimney of the exhaust and the bypass duct which is connected to the bypass chimney through the explosion-proof door which opens at a predetermined dynamic pressure of the exhaust. Is tilted to the upstream side to stand upright and close the bypass duct, and to fall down and open to the downstream side with a predetermined dynamic pressure of the exhaust gas.The explosion-proof door has an angle in the direction against the horizontal load due to the dynamic pressure of the exhaust gas. The vertical weight of the explosion-proof door causes a moment to always close the explosion-proof door due to the weight of the explosion-proof door. When the exhaust gas is released and the exhaust gas is released, the pressure of the exhaust gas in the exhaust duct is unstable, so the dynamic pressure of the exhaust gas causes the load to fluctuate and the explosion-proof door to transition. No longer can cause a chattering to repeat the closing.

[0009]

1 is an explanatory view of an exhaust duct according to an embodiment of the present invention. In the figure, the exhaust duct according to the present embodiment is used in a combined power generation plant of an exhaust gas boiler and a gas turbine, and generally, a combined power generation plant of an exhaust gas boiler and a gas turbine uses high pressure air compressed by a compressor. The gas turbine is rotated by using the high-temperature high-pressure gas generated by burning the fuel, the generator is driven by this gas turbine to generate electricity, and the exhaust gas discharged from the gas turbine is used to generate steam by the exhaust gas boiler. ,
This steam is used to rotate a steam turbine that drives a generator to generate electricity.

When the gas turbine is operated independently in such a combined cycle power plant, first, the damper 8a at the inlet of the bypass chimney 8 of the exhaust duct 6 provided between the gas turbine and the exhaust gas boiler is opened. Then, the damper 5a on the outlet side of the exhaust duct 6 for supplying air to the exhaust gas boiler is closed. At this time, if the damper 5a,
As an abnormal pressure rise prevention measure (explosion proof measure) in the exhaust duct 6 so that abnormal pressure rise does not occur in the exhaust duct 6 even if both the dampers 5a, 8a are closed due to a failure in switching operation between 8a A bypass duct 9 of a bypass chimney 8 having an explosion-proof door 7 is installed.

In the exhaust duct 6, the explosion-proof door 7 is installed so as to lean against the inlet of the bypass duct 9 of the bypass chimney 8 as shown in the figure, and is horizontally leveled by the dynamic pressure of the exhaust gas discharged from the gas turbine 2. It is provided so as to be tilted inward from a state in which the moment M in the direction of closing the explosion-proof door 7 is always applied by the own weight of the explosion-proof door 7 while opening at an angle in a direction against the load in the horizontal direction. Further, the mounting shaft 10 of the explosion-proof door 7 is connected to the bypass duct 9
Explosion-proof door 7 extends from outside the bypass duct 9 to the outside
A handle (not shown) is provided so that the handle can be opened and closed.

In the conventional exhaust duct, the explosion-proof door is installed in the bypass duct of the bypass chimney so as to open and close in the vertical direction, and when the gas turbine is operated independently, the exhaust gas is emitted from the bypass chimney. The force that pushes up the explosion-proof door acts by receiving the vertical load due to the dynamic pressure of. When this exhaust gas is discharged, the pressure of the exhaust gas in the exhaust duct is unstable.Therefore, the vertical load due to the dynamic pressure of the exhaust gas fluctuates, and the explosion-proof door may cause a transient chattering phenomenon. However, in this exhaust duct, the explosion-proof door 7 is tilted horizontally from the leaning state to open and close so that the explosion-proof door 7 is installed at an angle against the horizontal load due to the dynamic pressure of the exhaust gas. The moment M that always closes the explosion-proof door 7 acts due to the weight of the door 7, and if a horizontal load due to the dynamic pressure of exhaust gas that exceeds this moment M acts, the load balance is lost and the explosion-proof door 7 Since it opens, the explosion-proof door 7 is prevented from being damaged by chattering, and the noise caused by the collision between the explosion-proof door 7 and the seat surface is eliminated. Reliability is improved in the combined cycle power plant with Ira and the gas turbine.

[0013]

The exhaust duct according to the present invention is constructed as described above, and since the explosion-proof door does not cause chattering, noise due to the explosion-proof door being damaged by the chattering or the explosion-proof door colliding with the seat surface. Problems such as damage to the surrounding environment due to the occurrence can be solved.

[Brief description of drawings]

FIG. 1 (a) is a vertical cross-sectional view of an exhaust duct according to an embodiment of the present invention, and FIG. 1 (b) is BB in FIG. 1 (a).
FIG.

FIG. 2 (a) is a system diagram of a combined power generation plant of an exhaust gas boiler and a gas turbine, and FIG. 2 (b) is a vertical sectional view of a conventional exhaust duct.

FIG. 3 is an explanatory diagram of its operation.

[Explanation of symbols]

 5a Dunbar 6 Exhaust duct 7 Explosion-proof door 8 Bypass chimney 8a Dunbar 9 Bypass duct 10 Explosion-proof door mounting shaft

Claims (1)

[Claims] 1. An exhaust duct provided with an exhaust bypass chimney and a bypass duct connected to the bypass chimney via an explosion-proof door opened by a predetermined dynamic pressure of the exhaust, in which the explosion-proof door is inclined upstream. An exhaust duct which is erected upright and closes the bypass duct and falls down and opens at a predetermined dynamic pressure of exhaust gas.