JP2001033002A - Waste heat recovery boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste heat recovery boiler, which does not need to have many penetration parts in the ceiling casing of flue by simplifying a support structure of an air-water drum and evaporator pipe bundles. SOLUTION: The support system for pipe bundles 3 is simplified by supporting the lower end of a downcast pipe 4 by a flue bed 6, supporting a steam-water drum 1 above a flue ceiling casing 14 by the downcast pipe 4, and suspending evaporator pipe bundles 3 by riser pipes 2 between the air- water drum 1 and evaporation tube bundle upper headers 11. In addition, supporting the lower part of the steam-water drum 1 by the flue ceiling casing 14 eliminates the necessity of providing a seal structure at each of many penetration parts of the flue ceiling casing 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exhaust heat recovery boiler for recovering heat from exhaust gas discharged from a gas turbine,
In particular, the present invention relates to a structure capable of simplifying a support structure for a heat transfer tube group.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional structure for supporting an evaporator tube group of an exhaust heat recovery boiler. The exhaust heat recovery boiler shown in FIG. 2 is provided with a flue as a flow path of exhaust gas discharged from the gas turbine in a horizontal direction, and in the flue, a group of economizer tubes 15 and a group of evaporator tubes upstream of the exhaust gas flow therefrom. 3 and guides the water containing steam generated in the economizer tube group 15 to the water cylinder 1 disposed outside the flue ceiling casing 14, where the water and water are separated by the water cylinder 1 and separated from the steam. The water thus returned is returned to the evaporator tube group 3 via the downcomer 4 and further heated by the exhaust gas, water containing steam is sent to the steam cylinder 1, and the obtained steam is used by a steam turbine (not shown).

[0003] As shown in FIG. 2, a steam cylinder 1 is disposed on a flue ceiling casing 14 near a boiler evaporator tube group 3, and adopts a self-standing structure supported by two downcomers 4. are doing. The support structure of the water cylinder 1 and the downcomer 4 is a structure in which the downcomer 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, left and right stoppers 8. ing. A steady rest 13 is attached to the flue ceiling casing 14 of the downcomer 4.

[0004] The support structure of the lower header 5 of the evaporator tube group 3 which is the main equipment of the exhaust heat recovery boiler body is a self-supporting bottom support structure for each lower header 5. The self-supporting bottom support structure includes a pedestal 9 integrated on a flue floor 6 with a stopper 8 by bolts (not shown), and each lower header 5 is installed on the pedestal 9. The front-rear direction (gas flow direction) of the connecting portion between the lower header 5 and the receiving stand 9 is supported by the lower-header front-rear stopper 8, and the left-right direction (axial direction of the header) does not restrict thermal expansion. It has a slide structure.

[0005]

As described above, the steam cylinder 1 shown in FIG. 2 is supported by the support plate 7 of the flue floor 6 via the downcomer 4, while the evaporator tube group 3 is 1 is disposed on the flue floor 6 in the front-back (gas flow) direction of the support position, a support device for the evaporator tube group 3 is required in addition to the support plate 7, and the steam cylinder 1 and the evaporator A long riser pipe 2 is required as a connecting pipe between the upper group header 11 of the vessel group 3 and the flue ceiling casing 14, which has a large number of penetrating portions, and its gas leak prevention structure is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art by simplifying the structure for supporting the water cylinder and evaporator tube group without providing a large number of penetrations in the ceiling casing of the stack. It is to provide a waste heat recovery boiler that can be used.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to support a lower end of a downcomer by a flue floor, and to support a steam cylinder above a flue ceiling casing by the downcomer. By suspending the evaporator tube group by the connecting tube between the tube group upper headers, simplification of the evaporator tube group support device can be achieved.

That is, the present invention relates to a flue through which flue gas from a gas turbine flows in a substantially horizontal direction, and a group of heat transfer tubes arranged in the flue so that a heat transfer surface faces vertically and recovers heat from the flue gas. And an upper header connected to the heat transfer tube group;
A steam cylinder, which is connected to the upper header via a connecting pipe and temporarily stores water containing steam in the heat transfer tube group, and is disposed at an upper portion of a flue ceiling casing; Heat recovery boiler equipped with a downcomer returning the water separated from the heat transfer tube group to the heat transfer tube group, the lower end of the downcomer is supported by the flue floor, the downdraft is supported by the downcomer, and the downdraft and evaporator It consists of an exhaust heat recovery boiler in which an evaporator tube group is suspended by a connecting tube between the tube group upper headers and a steam cylinder or a downcomer tube is supported by a flue ceiling casing.

[0009]

According to the present invention, in a waste heat recovery boiler evaporator, the steam cylinder is supported by a downcomer pipe, and the evaporator pipe group is suspended by a riser pipe connecting the steam cylinder and the evaporator pipe group, whereby smoke is removed. The evaporator tube group support device installed on the roadbed can be eliminated. Further, the above configuration of the present invention eliminates the necessity of providing a seal structure for each penetrating portion of the flue ceiling casing of the connecting pipe between the multiple water cylinders and the evaporator pipe group upper header as in the prior art.

In the present invention, since the number of penetrations of the ceiling casing of the flue is smaller than that of the prior art, the number of sealing structures is reduced accordingly, and the structure for preventing gas leakage is simplified.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 related art of FIG. 2 are denoted by the same reference numerals, and description thereof may be omitted.

The water cylinder 1 disposed outside the flue ceiling casing 14 includes a downcomer 4 provided at the bottom of the water cylinder 1.
And is supported by the floor surface of the flue floor 6. An evaporator tube group 3 arranged at a symmetric position about the downcomer 4 in the longitudinal direction of the gas flow in the flue of the downcomer 4 is suspended from the lower surface of the water cylinder 1 by the riser 2 and supported.

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 steam cylinder 1, but the exhaust heat recovery of the present invention shown in FIG. In the boiler, the lower half of the water cylinder 1 and the riser 2 and the downcomer 4 are housed in a flue, and the through-hole of the flue ceiling casing 14 is eliminated.

With respect to the force acting in the horizontal direction of the water cylinder 1, a side surface of the water cylinder 1 is supported by a steady rest 13 provided outside the flue ceiling casing 14, and the water cylinder 1 and the evaporator tube are provided. The stress caused by thermal expansion with the group 3 is the bent water supply pipe 1 connecting the lower evaporator header 5 and the lower end of the downcomer 4.
Absorbed by 2.

Furthermore, the outer periphery of the one or more stages of evaporator tube groups 3 in the horizontal direction (gas flow direction) is surrounded by a mold 10 which is independent from the flue floor 6, and the external force of the evaporator tube group 3 in the horizontal direction is increased. To support bending.

[0016]

According to the present invention, the evaporator tube group can be hung in the flue with a simple structure, so that the evaporator tube group support device installed on the flue floor can be dispensed with. There is no need to provide a sealing structure for each through portion of the chimney ceiling casing in the connecting pipe between the many water cylinders and the evaporator pipe group upper header as in the prior art, and the gas leak preventing structure is simplified.

[Brief description of the drawings]

FIG. 1 is an evaporator support structure 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 related art.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 steam cylinder 2 riser 3 evaporator tube group 4 downcomer 5 evaporator lower header 6 flue floor 7 support plate 8 stopper 9 cradle 10 formwork 11 evaporator upper header 12 water supply pipe 13 steady rest 14 casing 15 Economizer tube group

Continued on the front page (72) Inventor Shigeyuki Iriki 6-9 Takara-cho, Kure-shi, Hiroshima Babcock Hitachi Kure Works F-term (reference) 3L103 AA01 BB05 CC18 CC27 DD08 DD42

Claims (3)

[Claims] 1. A flue through which flue gas from a gas turbine flows in a substantially horizontal direction, a group of heat transfer tubes arranged in the flue so that a heat transfer surface faces vertically and recovers heat from the flue gas;
An upper header connected to the heat transfer tube group and a flue ceiling casing connected to the upper header via a communication pipe and temporarily storing water containing steam in the heat transfer tube group. In a waste heat recovery boiler provided with a steam cylinder and a downcomer returning water separated from steam in the steam cylinder to the heat transfer tube group, a lower end of the downcomer is supported by a flue floor, and the It is supported by a downcomer pipe, the evaporator tube group is suspended by a connecting pipe between the steam cylinder and the upper elongate pipe group, and the steam cylinder or the downcomer pipe is supported by a flue ceiling casing. Waste heat recovery boiler. 2. A formwork, which is self-supporting on one or more stages of a flue floor surrounding the outer circumference of the heat transfer tube group in the exhaust gas flow direction and supports the deflection of the heat transfer tube group due to a horizontal external force. The exhaust heat recovery boiler according to claim 1, wherein: 3. The exhaust heat recovery boiler according to claim 1, wherein a connecting pipe between the steam cylinder and the upper header of the evaporator pipe group is housed in a flue.