JP4179433B2 - Waste heat recovery boiler - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust heat recovery boiler that recovers heat from exhaust gas discharged from a gas turbine, and more particularly to a structure that can simplify a support structure for a heat transfer tube group.
[0002]
[Prior art]
The support structure of the evaporator tube group of the conventional waste heat recovery boiler is shown in FIG. The exhaust heat recovery boiler shown in FIG. 2 is provided with a flue that serves as a flow path for the exhaust gas discharged from the gas turbine in the horizontal direction, and the economizer tube group 15 in the flue and the evaporator tube group upstream of the exhaust gas flow. 3, the water containing steam generated in the economizer tube group 15 is guided to the air / water cylinder 1 disposed outside the flue ceiling casing 14, and is separated from the steam by the air / air cylinder 1. The water thus returned is returned to the evaporator tube group 3 via the downcomer 4 and further heated with exhaust gas, and water containing steam is sent to the air / water cylinder 1 and the obtained steam is used in a steam turbine (not shown).
[0003]
As shown in FIG. 2, the air / water cylinder 1 is arranged on a flue ceiling casing 14 in the vicinity of the boiler evaporator tube group 3 and adopts a self-supporting structure supported by two downcomers 4. . The support structure of the air / water cylinder 1 and the downcomer pipe 4 is a structure in which the downcomer pipe 4 is supported by a support plate 7 on the flue floor 6, and the support plate 7 is fixed on the flue floor 6 by front and rear stoppers 8. ing. A steady rest 13 is attached to a through portion of the flue ceiling casing 14 of the downcomer 4.
[0004]
Further, the support structure of the lower header 5 of the evaporator tube group 3 which is the main device of the exhaust heat recovery boiler body is a self-supporting bottom support structure for each lower header 5. This self-supporting bottom support structure includes a cradle 9 integrated with a stopper 8 on a flue floor 6 with bolts (not shown), and each lower header 5 is installed on the cradle 9. The front / rear direction (gas flow direction) of the joint between the lower header 5 and the cradle 9 is supported by a front / rear direction stopper 8 for the lower header, and the left / right direction (axial direction of the header) does not restrain thermal expansion. It has a slide structure.
[0005]
[Problems to be solved by the invention]
2 is supported by the support plate 7 of the flue floor 6 via the downcomer 4, the evaporator tube group 3 is located before and after the support position of the air / water barrel 1 (gas flow). Since it is arranged on the flue bed 6 in the direction of flow), a support device for the evaporator tube group 3 is necessary in addition to the support plate 7, and the upper header 11 of the air / water cylinder 1 and the evaporator tube group 3 is required. A long ascending pipe 2 is required as a connecting pipe between the two and there are many through portions of the flue ceiling casing 14, and the structure for preventing gas leakage is complicated.
[0006]
The object of the present invention is to simplify the support structure of the air cylinder and the evaporator tube group for the purpose of eliminating the above-mentioned disadvantages of the prior art, and it is not necessary to provide a large number of through portions in the ceiling casing of the flue. It is to provide an exhaust heat recovery boiler.
[0007]
[Means for Solving the Problems]
The object of the present invention is to support the lower end of the downcomer pipe with a flue floor, and to support the air tunnel at the upper part of the flue ceiling casing with this downcomer pipe, and to connect the air tunnel to the upper header of the evaporator tube group. By suspending the evaporator tube group, simplification of the support device for the evaporator tube group can be achieved.
[0008]
That is, the present invention provides a flue for flowing the exhaust gas from the gas turbine in a substantially horizontal direction, a heat transfer tube group disposed in the flue so that the heat transfer surface faces in the vertical direction, and recovering heat from the exhaust gas, An upper header connected to the heat transfer tube group, and an air connected to the upper header via a connecting pipe, and temporarily stored in the heat transfer tube group, containing water containing steam, is placed in the upper part of the flue ceiling casing. In an exhaust heat recovery boiler equipped with a water cylinder and a precipitating pipe that returns water separated from steam in the air water cylinder to the heat transfer tube group again, the lower end of the precipitating pipe is supported by the flue floor, From an exhaust heat recovery boiler that is supported by a pipe, suspends the evaporator tube group by a connecting pipe between the air / water cylinder and the upper header of the evaporator tube group, and supports the air / water cylinder or the precipitation pipe by a flue ceiling casing Become.
[0009]
[Action]
According to the present invention, in the exhaust heat recovery boiler evaporator, the air / water cylinder is supported by the downpipe, and the evaporator tube group is suspended by the riser pipe connecting the air / water cylinder and the evaporator tube group. An evaporator tube group support device to be installed can be dispensed with. Further, according to the above-described configuration of the present invention, there is no need to provide a seal structure for each through portion of the flue ceiling casing of the connecting pipe between the large number of air / water cylinders and the upper header of the evaporator pipe group.
[0010]
In the present invention, since the number of through-holes in the ceiling casing of the flue is smaller than that of the prior art, the seal structure can be reduced correspondingly, and the gas leak prevention structure is simplified.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG. In FIG. 1, members having the same functions as those described in the prior art of FIG.
[0012]
The air / air cylinder 1 disposed outside the flue ceiling casing 14 is supported by the floor surface of the flue floor 6 via a downcomer 4 provided at the bottom of the air / air cylinder 1. Further, the evaporator tube group 3 arranged at a symmetrical position around the downcomer pipe 4 in the longitudinal direction of the gas flow in the flue of the downcomer pipe 4 is suspended and supported by the lower surface of the air / water cylinder 1 by the ascending pipe 2.
[0013]
Further, in the conventional exhaust heat recovery boiler shown in FIG. 2, the riser pipe 2 penetrates the flue ceiling casing 14 and is connected to the air / water cylinder 1, but in the exhaust heat recovery boiler of the present invention shown in FIG. The lower half of the water barrel 1, the riser pipe 2 and the downcomer pipe 4 are housed in the flue, and the through-hole of the flue ceiling casing 14 is eliminated.
[0014]
Regarding the force acting in the horizontal direction of the air / air cylinder 1, the side surface of the air / air cylinder 1 is supported by a steady rest 13 provided outside the flue ceiling casing 14, and the air / air cylinder 1 and the evaporator tube group 3 are supported. The stress due to the thermal elongation is absorbed by the bent water supply pipe 12 connecting the lower evaporator header 5 and the lower end of the downcomer pipe 4.
[0015]
Further, the outer periphery in the horizontal direction (gas flow direction) of the one or more stages of the evaporator tube group 3 is surrounded by a mold 10 that is self-supported from the flue floor 6, and the evaporator tube group 3 is bent by an external force in the horizontal direction. To support.
[0016]
【The invention's effect】
According to the present invention, the evaporator tube group can be suspended in the flue with a simple structure, so that an evaporator tube group support device installed on the flue floor can be dispensed with. It is no longer necessary to provide a seal structure for each penetration portion of the flue ceiling casing in the connecting pipe between the large number of air / water cylinders and the evaporator pipe group upper header, and the gas leak prevention structure is simplified.
[Brief description of the drawings]
FIG. 1 is an evaporator support structure diagram of an exhaust heat recovery boiler according to the present invention.
FIG. 2 is an evaporator support structure diagram of a waste heat recovery boiler according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Air cylinder 2 Rising pipe 3 Evaporator pipe group 4 Precipitation pipe 5 Evaporator lower header 6 Flue bed 7 Support plate 8 Stopper 9 Receptacle 10 Form 11 Evaporator upper header 12 Water supply pipe 13 Stabilization 14 Casing 15 Economizer tube group

Claims (3)

A flue through which the exhaust gas from the gas turbine flows almost horizontally, a heat transfer tube group that recovers heat from the exhaust gas, and is connected to the heat transfer tube group. An upper header connected to the upper header through a communication pipe, and temporarily storing water containing steam in the heat transfer tube group, In the exhaust heat recovery boiler equipped with a downcomer that returns the water separated from the steam in the steam cylinder back to the heat transfer tube group,
The lower end of the downcomer is supported by the flue floor, the air canister is supported by the downcomer, the evaporator tube group is suspended by the connecting pipe between the air canister and the upper part of the evaporator tube group, and An exhaust heat recovery boiler in which a trunk or a downcomer is supported by a flue ceiling casing. And a mold for supporting the bending of the heat transfer tube group due to the external force in the horizontal direction, which is self-supporting on the one or more flue floor surfaces surrounding the outer periphery of the heat transfer tube group in the exhaust gas flow direction. The exhaust heat recovery boiler according to claim 1. The exhaust heat recovery boiler according to claim 1, wherein a communication pipe between the air / water cylinder and the upper header of the evaporator pipe group is housed in the flue.

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