U.S. patent application number 10/523033 was filed with the patent office on 2006-07-13 for furnace wall structure.
This patent application is currently assigned to BABCOCK-HITACHI KABUSHIKI KAISHA. Invention is credited to Atsushi Furukawa, Junichiro Matsuda, Toshihiko Okamoto.
Application Number | 20060150874 10/523033 |
Document ID | / |
Family ID | 31973186 |
Filed Date | 2006-07-13 |
United States Patent
Application |
20060150874 |
Kind Code |
A1 |
Okamoto; Toshihiko ; et
al. |
July 13, 2006 |
FURNACE WALL STRUCTURE
Abstract
A furnace wall comprises: a furnace wall bottom part composed of
furnace wall tubes having upward-spiraled fluid passages; a nose
part which has nose wall tubes disposed in a middle part of a
furnace rear wall adjoining the furnace wall bottom part; and a
screen part having screen tubes, wherein the terminal parts of the
furnace wall tubes are located lower than the nose part.
Consequently, the drain generated in the nose wall tubes while the
operation of the boiler is suspended can naturally fall inside the
furnace wall tubes located lower than the nose part, and in a case
where the header is connected with the terminal parts of the
furnace wall tubes, the drain generated in the nose wall tubes can
naturally fall inside the header. In addition, the furnace wall
tubes which extend upright from the terminal parts of the furnace
wall tubes can be provided to connect parts of the furnace wall
tubes directly with the header, to connect the header with the nose
wall tubes via vertical tubes and; and to connect other parts of
the furnace wall tubes directly with the screen tubes, thereby
integrating the vertical furnace wall tubes, the vertical tubes,
and the screen tubes by being welded via membrane bars. This
results in the furnace wall structure not requiring reinforcing
supports for supporting the weight of the furnace wall bottom
part.
Inventors: |
Okamoto; Toshihiko;
(Hiroshima, JP) ; Matsuda; Junichiro; (Hiroshima,
JP) ; Furukawa; Atsushi; (Hiroshima, JP) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
BABCOCK-HITACHI KABUSHIKI
KAISHA
WORLD TRADE CENTER BLDG. HAMAMATSUCHO 2-CHOME MINA TO-KU
JP
|
Family ID: |
31973186 |
Appl. No.: |
10/523033 |
Filed: |
September 8, 2003 |
PCT Filed: |
September 8, 2003 |
PCT NO: |
PCT/JP03/11425 |
371 Date: |
February 2, 2005 |
Current U.S.
Class: |
110/336 ;
122/467; 122/510 |
Current CPC
Class: |
F22B 29/065 20130101;
F22B 37/645 20130101 |
Class at
Publication: |
110/336 ;
122/467; 122/510 |
International
Class: |
F23M 5/00 20060101
F23M005/00; F22G 1/02 20060101 F22G001/02; F22B 37/24 20060101
F22B037/24 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 9, 2002 |
JP |
2002-263449 |
Claims
1. A furnace wall structure having a furnace wall installed in a
furnace which is the combustion chamber of a boiler for thermal
power generation, said furnace wall comprising: a furnace wall
bottom part composed of furnace wall tubes having upward-spiraled
fluid passages; a nose part which has nose wall tubes disposed in a
middle part of a furnace rear wall adjoining the furnace wall
bottom part; and a screen part having screen tubes, wherein the
terminal parts of said furnace wall tubes are located lower than
the nose part, a header is provided at the connection part between
the terminal parts of said furnace wall tubes and said nose wall
tubes, and is installed lower than said nose Dart and outside the
furnace wall, furnace wall tubes which extend upright from the
terminal parts of said furnace wall tubes are provided so as to
connect parts of the furnace wall tubes directly with the header,
to connect the header with the nose wall tubes via vertical tubes;
and to connect other Darts of said furnace wall tubes directly with
the screen tubes, thereby integrating the vertical furnace wall
tubes, the vertical tubes, and the screen tubes by being welded via
membrane bars.
2. (canceled)
3. (canceled)
4. The furnace wall structure according to claim 1, wherein the
parts of said vertical furnace wall tubes are bent downwards to be
connected with the header; horizontal tubes are provided in such a
manner as to be divided from the header into opposite sides in the
horizontal direction; the horizontal tubes are connected with the
vertical tubes which partly extend upright adjacent to the vertical
furnace wall tubes via the vertical tubes and the horizontal tubes;
and the vertical tubes are connected with the nose wall tubes,
respectively.
5. The furnace wall structure according to claim 1, further
comprising: drain tubes provided at the bottom of the header; and
an open/close valve provided at the drain tubes.
Description
TECHNICAL FIELD
[0001] The present invention relates to a furnace structure
composed of a combustion chamber which is the steam generator of a
boiler for thermal power generation, and more specifically, to the
furnace wall structure of the furnace rear wall.
BACKGROUND ART
[0002] FIG. 6 shows a simplified side view of the wall tubes
forming the wall face of the furnace which composes the combustion
chamber of a conventional boiler for thermal power generation.
[0003] The combustion chamber of the boiler for thermal power
generation is composed of a furnace wall 1 formed by arraying
furnace wall tubes 2a for conveying water, steam, or a fluid
mixture of them at regular intervals, and welding these furnace
wall tubes 2a via membrane bars 3 disposed therebetween (See FIG.
2).
[0004] The furnace wall 1 is provided with a furnace wall bottom
part A composed of the furnace wall tubes 2a having upward-spiraled
fluid passages; a nose part C which has nose wall tubes 5a disposed
in a middle part of a furnace rear wall B adjoining the furnace
wall bottom part A with a side view resembling a sidewise V (<);
and a screen part D having screen tubes 7.
[0005] There are also plural burners 4 provided for supplying fuel
from outside for combustion, which are arrayed in each of the
plural stages provided in the vertical direction at corresponding
positions on the lower side of the front wall and rear wall of the
gas flow of the furnace wall 1. These burners 4 heat the fluid
inside the furnace wall tubes 2a and make it move upwards from the
furnace wall bottom part A inside the inclined furnace wall tubes
2a.
[0006] The fluid heated by the burners 4 receives a different
amount of heat depending on the arrayed position of the furnace
wall tube 2a provided for conveying the fluid, and on the
positional relationship between the furnace wall tube 2a and the
burners 4. Therefore, in order to make the amount of heat received
by the fluid uniform, regardless of the arrayed position of the
furnace wall tube 2a and the positional relationship between the
furnace wall tube 2a and the burners 4, the furnace wall tubes 2a
in the furnace wall bottom part A are upward-spiraled. Such a
structure of the upward-spiraled furnace wall tubes 2a of the
conventional boilers for thermal power generation is disclosed in
Japanese Published Unexamined Patent Application No. 2000-130701,
paragraph [0027].
[0007] FIG. 7 and FIG. 8 (as viewed from the direction of the lines
II-II of FIG. 7) show a detailed structure of the connection part
(hereinafter also referred to as the-transition part) between the
spiral furnace wall tubes 2a in the furnace rear wall, and the nose
wall tubes 5a and the screen tubes 7.
[0008] The combustion gas G in the furnace, as shown in FIG. 6,
rises from the furnace wall bottom part A; turns at the nose part C
to the left side on the drawing; passes through the furnace ceiling
part; and then flows towards an unillustrated furnace rear heat
transfer part. Thus, the combustion gas Grises while making a
detour in the upper part of the furnace wall 1. In contrast, if the
nose part C is absent, the combustion gas G generated at the
burners 4 region at the furnace wall bottom part A flows towards
the right side on FIG. 6; passes through the furnace ceiling part;
and flows towards the unillustrated furnace rear heat transfer
part. Without the nose part C, the combustion gas G flows the
shortest route in the furnace wall 1 in this manner, which shortens
the retention time of the combustion gas G in the furnace, thereby
making the combustion of the fuel insufficient. The shortened
retention time of the combustion gas G in the furnace also makes
the heat storing insufficient in the furnace wall tubes 2a and the
other heat transfer tube regions in the furnace, thereby causing
high-temperature combustion gas G to flow to the furnace rear heat
transfer part side. The high-temperature combustion gas G causes
the heat transfer tubes arranged on the furnace rear heat transfer
part to have clinkers or slag, which are difficult to remove after
being hardened.
[0009] This makes it necessary to provide the nose part C which
must have a complicated tubing structure. The terminal parts of the
spiral furnace wall tubes 2a are positioned in the intermediate
part of the nose part C composed of the nose wall tubes 5a and
others. Consequently, the header 6 for adjusting the number of
tubes and mixing the inner fluid, which is required in the
connection part (transition part) between the spirally inclined
furnace wall tubes 2a and the screen tubes 7 because of the
difference in number between the furnace wall tubes 2a and the nose
wall tubes 5a, is conventionally disposed inside the nose part C as
shown in FIG. 7.
[0010] Other furnace wall tubes 2b, which extend upright from the
inclined terminal parts of the furnace wall tubes 2a whose fluid
passages are upward-spiraled, are connected with the header 6. Then
the header makes the fluid flow towards the nose wall tubes 5a.
Between the header 6 and the nose wall tube 5a are provided fluid
passages 5f for conveying the inner fluid downwards. The fluid
passages 5f are arranged in parallel with the vertical furnace wall
tubes 2b.
[0011] In the transition part, the inclined terminal parts of the
furnace wall tubes 2a are directly connected with the screen tubes
7, which are composed of thick tubes with higher rigidity than the
furnace wall tubes 2a so as to support the weight of the furnace
wall bottom part A by a small number. However, it is impossible to
transfer the weight of the furnace wall bottom part A to the screen
tubes 7 only by the furnace wall tubes 2a with insufficient
rigidity. Therefore, there are reinforcing supports 8 provided
between the furnace wall tubes 2a and the screen tubes 7 in order
to compensate for the rigidity of the furnace wall tubes 2a and to
transfer the weight of the furnace wall bottom part A to the screen
tubes 7.
[0012] According to the aforementioned prior art, since the
terminal parts of the spirally inclined furnace wall tubes 2a are
located in the intermediate part of the nose part C, the header 6
is provided to compensate for the difference in number between the
furnace wall tubes 2a and the nose wall tubes 5a and to mix the
inner fluid. The header 6 is installed inside the nose part C, and
the inner fluid coming out of the header 6 flows through fluid
passages 5f into the nose wall tubes 5a whose side views resembles
a sidewise V (<).
[0013] Thus in the conventional furnace wall structure, the water
inside the fluid passages 5f located lower than the header 6 cannot
be drained while the operation of the boiler is suspended.
[0014] Furthermore, according to the prior art, the reinforcing
supports 8 must be installed in the screen tubes 7 that are
directly connected with the spirally inclined furnace wall tubes
2a, and such a complicated structure leads to a cost increase.
[0015] The object of the present invention is to provide a furnace
wall structure which can drain the water inside the nose wall tubes
while the operation of the boiler is suspended, and also to provide
a furnace wall structure which can dispense with the reinforcing
supports for supporting the weight of the furnace wall bottom
part.
DISCLOSURE OF THE INVENTION
[0016] The present invention is a furnace wall structure having a
furnace wall 1 installed in a furnace which is the combustion
chamber of a boiler for thermal power generation, the furnace wall
1 comprising: a furnace wall bottom part A composed of furnace wall
tubes 2a having upward-spiraled fluid passages; a nose part C which
has nose wall tubes 5a disposed in a middle part of a furnace rear
wall B adjoining the furnace wall bottom part A; and a screen part
D having screen tubes 7, wherein the terminal parts of the furnace
wall tubes 2a are located lower than the nose part C.
[0017] Since the terminal parts of the furnace wall tubes 2a are
located lower than the nose part C, the drain generated in the nose
wall tubes 5a while the operation of the boiler is suspended can
naturally fall inside the furnace wall tubes 2a located lower than
the nose part C.
[0018] Also, in a case where the header 6 is connected with the
terminal parts of the furnace wall tubes 2a, the terminal parts of
the furnace wall tubes 2a are located lower than the nose part C,
which makes the drain generated in the nose wall tubes 5a naturally
fall inside the header 6.
[0019] Furthermore, the header 6 can be installed lower than the
nose part C and also outside the furnace wall 1. In this case, the
header 6 installed outside the furnace wall 1 facilitates draining
operations from the header 6 and maintenance operations.
[0020] It is also possible that furnace wall tubes 2b (2b.sub.1,
2b.sub.2) which extend upright from the terminal parts of the
furnace wall tubes 2a are provided so as to connect parts 2b.sub.1
of the furnace wall tubes 2b directly with the header 6, to connect
the header 6 with the nose wall tubes 5a via vertical tubes
5e.sub.1 and 5e.sub.2; and to connect other parts 2b.sub.2 of the
furnace wall tubes 2b directly with the screen tubes 7, thereby
integrating the vertical furnace wall tubes 2b (2b.sub.1,
2b.sub.2), the vertical tubes 5e.sub.1 and 5e.sub.2, and the screen
tubes 7 by being welded via membrane bars 3.
[0021] Thus, in the present invention, the terminal parts of the
furnace wall tubes 2a having the spirally inclined fluid passages
are located lower than the nose part C, which makes it possible to
provide the furnace wall tubes 2b (2b.sub.1, 2b.sub.2) extending
upright between the terminal parts of the furnace wall tubes 2a and
the nose wall tubes 5a. This enables the parts 2b.sub.2 of the
furnace wall tubes 2b to be directly connected with the screen
tubes 7 so as to integrate the vertical furnace wall tubes 2b
(2b.sub.1, 2b.sub.2), the vertical tubes 5e.sub.1 and 5e.sub.2, and
the screen tubes 7 by being welded via the membrane bars 3, thereby
supporting the weight of the furnace wall bottom part A without
using reinforcing members.
[0022] It is also possible that the parts 2.sub.b.sub.1 of the
vertical furnace wall tubes 2b are bent downwards to be connected
with the header 6; horizontal tubes 5b.sub.1 and 5b.sub.2 are
provided in such a manner as to be divided from the header 6 into
opposite sides in the horizontal direction; the horizontal tubes
5b.sub.1 and 5b.sub.2 are connected with the vertical tubes
5e.sub.1 and 5e.sub.2 which partly extend upright adjacent to the
vertical furnace wall tubes 2b (2b.sub.1, 2b.sub.2) via the
vertical tubes 5c.sub.1 and 5c.sub.2 and the horizontal tubes
5d.sub.1 and 5d.sub.2; and the vertical tubes 5e.sub.1 and 5e.sub.2
are connected with the nose wall tubes 5a, respectively.
[0023] Thus, the header 6 and the nose wall tubes 5a are connected
with each other via a connection tube group (5b.sub.1, 5b.sub.2 to
5e.sub.1, 5e.sub.2) consisting of the horizontal tubes 5b.sub.1,
5b.sub.2, 5d.sub.1, and 5d.sub.2, the vertical tubes 5c.sub.1 and
5c.sub.2, and the vertical tubes 5e.sub.1 and 5e.sub.2. The
connection tube group (5b.sub.1, 5b.sub.2to 5e.sub.1, 5e.sub.2)
never causes drain retention, thereby making the drain from the
nose wall tubes 5a naturally fall into the header 6 quickly.
[0024] Although it is not illustrated, the furnace wall 1 is
suspended from the ceiling joist supported by a steel column, and
the header 6, which is also a heavy material, is also suspended
from an adjacent ceiling joist via a spring arm. The furnace wall 1
moves downwards by several to several tens of centimeters by heat
extension, and the spring arm can follow the heat extension of the
header 6 in the vertical direction, but not the heat extension of
the furnace wall 1 in the horizontal direction. However, the
connection tube group (5b.sub.1, 5b.sub.2 to 5e.sub.1, 5e.sub.2),
particularly the portions having a side view of an inverted L
formed by the vertical tubes 5c.sub.1 and 5c.sub.2 and the
horizontal tubes 5d.sub.1 and 5d.sub.2 can absorb the heat
extension of the furnace wall 1 in the horizontal direction.
[0025] To provide drain tubes 5d at the bottom of the header 6 and
to provide an open/close valve 10 at the drain tubes 5d facilitate
the draining from the header 6.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 shows a side view of the furnace wall structure of
the embodiment of the present invention;
[0027] FIG. 2 is a perspective view of a part of the furnace wall
structure of FIG. 1;
[0028] FIG. 3 is a detailed side view of the furnace wall structure
of FIG. 1;
[0029] FIG. 4 is a view seen from the direction indicated by the
arrows I, I of FIG. 3;
[0030] FIG. 5 is an enlarged view of a part of FIG. 4;
[0031] FIG. 6 is a side view of the conventional furnace wall
structure;
[0032] FIG. 7 is a detailed side view of the conventional furnace
wall structure; and
[0033] FIG. 8 is a perspective view taken along the line II-II of
FIG. 7.
BEST MODE FOR CARRYING OUT THE INVENTION
[0034] An embodiment of the present invention will be described as
follows with the drawings. The boiler furnace wall structure of the
present embodiment is shown in FIG. 1 to FIG. 5.
[0035] Concerning the boiler furnace wall structure of the present
embodiment, FIG. 1 shows its simplified side view; FIG. 2 shows a
perspective view of a partly cut portion of the furnace wall
structure; FIG. 3 shows an enlarged side view of the transition
part of the furnace wall tubes from the furnace wall tubes to the
nose part; and FIG. 4 shows a view seen from the direction
indicated by the arrows I and I of FIG. 3. FIG. 5 is an enlarged
view of a part of FIG. 4.
[0036] The furnace wall 1 shown in FIG. 1 is provided with a
furnace wall bottom part A composed of furnace wall tubes 2a having
upward-spiraled fluid passages; a nose part C having nose wall
tubes 5a which is disposed in a middle part of a furnace rear wall
B adjoining the furnace wall bottom part A; and an upper screen
part D having screen tubes 7.
[0037] In the furnace wall 1 of the present embodiment, the
terminal parts of the upward-spiraled furnace wall tubes 2a are
located lower than the nose part C having the nose wall tubes 5a.
Furthermore, the present embodiment employs a boiler structure
where the header 6 for adjusting the number of tubes and mixing the
inner fluid that is required because of the difference in number
between the furnace wall tubes 2a and the nose wall tubes 5a is
installed lower than the nose part C and also outside the furnace
wall 1.
[0038] As shown in FIG. 3 to FIG. 5, the terminal parts of the
upward-spiraled furnace wall tubes 2a are located lower than the
nose part C; between the terminal parts of the furnace wall tubes
2a and the nose part C are provided vertical furnace wall tubes 2b
(2b.sub.1, 2b.sub.2) extending higher than the terminal parts of
the furnace wall tubes 2a; and the header 6 for adjusting the
number of tubes and mixing the inner fluid that is required because
of the difference in number between the furnace wall tubes 2b
(2b.sub.1, 2b.sub.2) and the nose wall tubes 5a is installed lower
than the nose part C and also outside the furnace wall 1. The parts
2b.sub.1 of the furnace wall tubes 2b are bent downwards to be
connected with the header 6. Furthermore, there are horizontal
tubes 5b.sub.1 and 5b.sub.2 which are divided from the header 6
into opposite sides in the horizontal direction, and which are
connected with the vertical tubes 5c.sub.1 and 5c.sub.2 partly
extending upright adjacent to the inclined furnace wall tubes 2a.
The vertical tubes 5c.sub.1 and 5c.sub.2 are connected, via the
horizontal tubes 5d.sub.1 and 5d.sub.2, with vertical tubes
5e.sub.1 and 5e.sub.2, respectively which partly extend upright
adjacent to the furnace wall tubes 2b (2b.sub.1, 2b.sub.2). The
vertical tubes 5e.sub.1 and 5e.sub.2 are connected with the nose
wall tubes 5a whose side views look like a sidewise V (<).
[0039] The provision of drain tubes 5d at the bottom of the header
6 and the provision of an open/close valve 10 at the drain tubes 5d
facilitate the draining from the header 6 through the drain tubes
5d.
[0040] The screen tubes 7 are connected with the parts 2b.sub.2 Of
the vertical furnace wall tubes 2b adjoining the spiral furnace
wall tubes 2a, and are composed of comparatively thick tubes so as
to support the weight of the furnace wall bottom part A.
[0041] In the furnace wall structure of the present embodiment, the
terminal parts of the upward-spiraled furnace wall tubes 2a are
located lower than the nose part C, so that the header 6 that is
required in the transition part because of the difference in number
between the furnace wall tubes 2a and the nose wall tubes 5a can be
installed lower than the nose part C and also outside the furnace
wall 1. This structure has the following effects.
[0042] (1) It becomes possible to provide, in the connection part
between the header 6 and the nose wall tubes 5a, wall tubes (the
vertical tubes 5c.sub.1 and 5c.sub.2 and the vertical tubes
5e.sub.1 and 5e.sub.2) extending upright to make the inner fluid
flow upwards, so that the water inside the nose wall tubes 5a can
naturally fall to the header 6 while the operation of the boiler is
suspended.
[0043] (2) Locating the terminal parts of the upward-spiraled
furnace wall tubes 2a lower than the nose part C enables upright
extended at the connection part between the spiral furnace wall
tubes 2a and the screen tubes 7, the furnace wall tubes 2b.sub.1
are connected with the header 6, and the header 6 is connected with
the nose wall tubes 5a via the vertical tubes 5e.sub.1 and 5e.sub.2
so as to integrate the vertical tubes 5e.sub.1 and 5e.sub.2, the
screen tubes 7, and the vertical furnace wall tubes 2b.sub.1 and
2b.sub.2 by being welded via the membrane bars 3, thereby
supporting the weight of the furnace wall bottom part A.
[0044] (3) The provision of the drain tubes 5d at the bottom of the
header 6 and the provision of the open/close valve 10 at the drain
tubes 5d facilitate the draining from the header 6 by operating the
open/close valve 10 installed outside the furnace wall 1, and also
facilitates the maintenance operation of the header 6 and the
adjacent tube group from outside the furnace wall 1.
INDUSTRIAL APPLICABILITY
[0045] According to the present invention, there is no accumulation
of water which is the inner fluid inside the nose wall tubes 5a
while the operation of the boiler is suspended, which facilitates
maintenance as compared with the conventional case. Furthermore,
the reinforcing supports conventionally installed to support the
weight of the furnace wall bottom part A become unnecessary,
thereby relatively reducing the cost of equipment.
* * * * *