U.S. patent application number 11/171903 was filed with the patent office on 2006-01-05 for grate panel, as well as corresponding incineration grate and waste incineration plant.
This patent application is currently assigned to Lurgi Lentjes AG. Invention is credited to Anton Esser, Norbert Kuppers.
Application Number | 20060000396 11/171903 |
Document ID | / |
Family ID | 35033669 |
Filed Date | 2006-01-05 |
United States Patent
Application |
20060000396 |
Kind Code |
A1 |
Esser; Anton ; et
al. |
January 5, 2006 |
Grate panel, as well as corresponding incineration grate and waste
incineration plant
Abstract
The invention pertains to a grate panel for an incineration
grate, an incineration grate composed of grate panels, as well as a
solid waste incineration plant with such an incineration grate.
Inventors: |
Esser; Anton; (Kaarst,
DE) ; Kuppers; Norbert; (Monchen-Gladbach,
DE) |
Correspondence
Address: |
KUSNER & JAFFE;HIGHLAND PLACE SUITE 310
6151 WILSON MILLS ROAD
HIGHLAND HEIGHTS
OH
44143
US
|
Assignee: |
Lurgi Lentjes AG
|
Family ID: |
35033669 |
Appl. No.: |
11/171903 |
Filed: |
June 30, 2005 |
Current U.S.
Class: |
110/281 ;
110/298 |
Current CPC
Class: |
F23H 17/12 20130101;
F23H 3/04 20130101 |
Class at
Publication: |
110/281 ;
110/298 |
International
Class: |
F23G 1/00 20060101
F23G001/00; F23H 7/08 20060101 F23H007/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 3, 2004 |
DE |
10 2004 032 291.0 |
Claims
1. A grate panel for an incineration grate with the following
characteristics: a) the grate panel has an upper side (10), a lower
side (12), two long sides (14, 16) and two broadsides; b) the grate
panel comprises at least one device for connecting a support
element (20) adjacent to a first long side (14), and c) at least
one flow channel (32) is arranged underneath the upper side (10)
and adjacent to a second long side (16), wherein air is conveyed
along said flow channel (32) from a region that is situated
underneath the grate panel to an opening (32o) in a section (16u)
of the second long side (16) that is situated adjacent to the lower
side (12).
2. The grate panel according to claim 1, wherein the grate panel is
realized with a plurality of recesses (22) underneath the upper
side (10), and wherein said recesses are open toward the lower side
(12) and extend from a region (14a) that is situated adjacent to
the first long side (14) to a region that is situated adjacent to
the second long side (16).
3. The grate panel according to claim 1, wherein the flow channel
(32) of the grate panel extends perpendicular to the long sides
(14, 16) of the grate panel.
4. The grate panel according to claim 1, wherein the flow channel
(32) of the grate panel has a length that corresponds to 10-50% of
the length of the broadsides.
5. The grate panel according to claim 1, wherein the second long
side (16) of the grate panel extends at an angle
.alpha.<90.degree. relative to the upper side (10).
6. The grate panel according to claim 1, wherein the second long
side (16) of the grate panel is angled (16w) at least once.
7. The grate panel according to claim 1, wherein an upper (outer)
wall of the flow channel (32) is formed by the upper side (10) and
the second long side (16).
8. The grate panel according to claim 1, wherein a lower (inner)
wall (30) of the flow channel (32) is formed by a rib extending
between walls (24) that form lateral limitations of the
corresponding recess (22).
9. The grate panel according to claim 1, which lower side (12) is
designed such that the upper side (10) of the grate panel extends
in an ascending fashion from the first long side (14) to the second
long side (16) when the grate panel is supported on a horizontal
surface.
10. The grate panel according to claim 1, which lower side (12),
adjacent to the second long side (16), is realized with a
downwardly protruding projection (30v).
11. The grate panel according to claim 1, which upper side (10) is
realized thinner in its section (10v) that is situated adjacent to
the flow channel (32) than in the section (10r) that lies behind
the flow channel (32).
12. The grate panel according to claim 1, wherein the second long
side (16) is realized thinner in its section that is situated
adjacent to the flow channel (32) than the upper side (10) in the
section (10r) that lies behind the flow channel (32).
13. The grate panel according to claim 1, comprising several
interconnected segments (T1, T2) that adjoin one another in the
direction of the long sides (14, 16).
14. The grate panel according to claim 13, wherein the at least one
recess (22) is formed by two adjoining segments (T1, T2).
15. An incineration grate, particularly a reciprocating
incineration grate, with a plurality of grate panels according to
claim 1.
16. A waste incineration plant with an incineration grate according
to claim 15.
Description
[0001] The invention pertains to a grate panel for an incineration
grate, an incineration grate composed of such grate panels, as well
as a waste (refuse) incineration plant with such an incineration
grate.
[0002] The most important component of a waste incineration plant
is the incineration grate that is arranged horizontally or in an
inclined fashion and on which the material to be incinerated, for
example, garbage, is conveyed from a first end to a second end that
is usually referred to as the burnout grate. The required
incineration air is forced through the incineration grate.
Corresponding openings are provided in the incineration grate for
this purpose. This means that the material being incinerated (waste
material) is essentially processed in three steps, namely "dried,"
then "incinerated" and ultimately converted into slag. These three
steps may be individually controlled, if so required.
[0003] There exist various types of incineration grates including,
among other things, the so-called reciprocating incineration grate.
Such a grate comprises movable parts (grate panels) that are able
to carry out stoking movements in order to convey the material
being incinerated (the refuse) along the incineration grate. The
individual grate panels lie on top of one another such that they
are offset in a stair-like fashion in the region of their long side
that points to the incineration chamber. For example, if every
second grate panel is realized in a movable fashion, the movement
of such a grate panel causes the solid waste lying on the
respectively ensuing grate panel referred to the transport
direction to be additionally conveyed to the next grate panel.
[0004] Different types of waste can be incinerated in an
incineration plant of the previously described type. Typical waste
materials are household garbage, industrial garbage, wood sawdust,
waste wood, used wood, processed fractions of various waste
materials (RDF=refuse derived fuel), biomasses or the like, for
example, sludge. The individual types of waste materials differ
with respect to their calorific value. However, this also applies
within the individual types of waste materials. For example,
household garbage may have a calorific value between 5 and 20
MJ/kg. The thermal and mechanical stresses on the incineration
grate or its grate panels, respectively, vary in dependence on this
calorific value.
[0005] This wear phenomenon can be sufficiently counteracted by
cooling the grate panels with air when incinerating waste with a
calorific value up to approximately 10 MJ/kg. An air-cooled
incineration grate is described in EP 0 391 146 A1.
[0006] When incinerating materials with a higher calorific value,
it is frequently preferred to utilize incineration grates, the
grate panels of which are cooled with a liquid, e.g., water.
However, the expenditures for such a water-cooling system are
significantly higher than those for an air-cooling system. The more
effective water cooling also leads to a more intensive cooling of
the grate panels that is undesirable in certain incineration
processes.
[0007] The invention is based on the objective of disclosing an
option for also incinerating materials (waste material) with higher
calorific values, particularly calorific values>10 MJ/kg, by
means of an air-cooling system.
[0008] This objective is attained based on the following notion:
each grate panel is primarily subjected to particularly intense
thermal stresses toward the incineration chamber, i.e., on its
upper side and its front face. Primary air is conveyed against the
lower side of the grate panels, i.e., it cools these grate panels
from the bottom, and forced into the layer of material being
incinerated that lies on the grate panels through openings in the
grate panels or between the grate panels. A certain cooling volume
for carrying off the generated heat is available underneath the
thermally stressed section of each grate panel. However, the
cooling effect is insufficient, particularly in the edge region.
This means that such regions, for example, the face (long side) of
a grate panel that points to the incineration chamber, are at risk
of corroding and eroding.
[0009] The invention proposes to arrange at least one flow channel
in the region underneath the upper side and adjacent to the front
long side of the grate panel, wherein air is conveyed from below in
a targeted fashion against the upper side and the adjacent front
long side.
[0010] This design forms a structure similar to an air nozzle,
wherein the air cools the critical front section of the respective
grate panel (that points to the incineration chamber) "from below"
with a correspondingly high flow speed.
[0011] This at least one flow channel is also realized with an air
outlet opening in the section of the corresponding face (face area)
that is situated adjacent to the lower side, namely such that the
air flow is subsequently conveyed in a targeted fashion onto the
surface of the ensuing grate panel--referred to the conveying
direction of the material being incinerated--and also cools this
surface. This targeted air flow against the adjacent grate panel
provides the additional advantage of largely preventing deposits
observed in the state of the art at this location. Such deposits
are also referred to as pick-ups and produced on incineration
grates according to the state of the art, for example, by metals
precipitating from the material being incinerated.
[0012] The conventional cooling system used so far serves for
cooling the "rear" section of the grate panel.
[0013] According to its most general embodiment, the invention
pertains to a grate panel for an incineration grate with the
following characteristics: [0014] the grate panel has an upper
side, a lower side, two long sides and two broadsides; [0015] the
grate panel comprises at least one device for connecting a support
element adjacent to a first long side, and [0016] at least one flow
channel is arranged underneath the upper side and adjacent to the
second long side, wherein air is conveyed along said flow channel
from a region that is situated underneath the grate panel to an
opening in the section of the second long side that is situated
adjacent to the lower side.
[0017] In one embodiment, the grate panel is realized with a
plurality of recesses underneath the upper side, wherein said
recesses are respectively open toward the lower side and extend
from a region that is situated adjacent to the first long side to a
region that is situated adjacent to the second long side.
[0018] These recesses make it possible to realize the upper side
(upper face area of the grate panel) with a relatively small
thickness, for example, of 10-15 mm.
[0019] In one embodiment, the flow channel or the flow channels
extend(s) perpendicular to the long sides of the grate panel. In
other words: the air flows along the flow channels in the direction
toward the front face area of the grate panel.
[0020] As mentioned above, this "front" section of the grate panels
is particularly at risk. In this respect, the length of the flow
channel can normally be limited to a length that corresponds to
10-50% of the grate panel width, wherein a length between 10 and
30% usually suffices. This is in particular the panel section that
is not passed (covered) by an adjacent panel in a reciprocating
incineration grate.
[0021] The periphery of a grate panel (also called grate plate)
usually does not have an exactly cuboid shape. The front face area
(second long side), in particular, does not extend perpendicular to
the upper side of the grate panel. The second long side may extend
at an angle .alpha.<90.degree. relative to the upper side and,
if so required, be additionally angled at least once.
[0022] With respect to the flow channel, this means that the flow
channel also does not extend in a straight fashion, but rather
follows the shape of the grate panel in this region. For example,
the flow channel describes--if viewed in the form of a section--a
semicircle or is angled several times. This simultaneously results
in a longer flow channel. The cooling effect can be intensified if
the flow channel extends relatively close to the respective surface
areas of the grate panel. In other words: an upper (outer) wall of
the flow channel is formed by an (inner) surface of the upper side
and an (inner) surface of the second long side in this case.
[0023] A lower (inner) wall of the flow channel may be formed by a
rib extending between walls or webs that form, for example, lateral
limitations of the aforementioned recesses.
[0024] The support of adjacent grate panels and the transport of
the material being incinerated along the incineration grate can be
simplified if the lower side of the grate panel (also referred to
as grate stage) is realized such that the upper side of the grate
panel is inclined (for example, by 3-10.degree.) from the first
long side to the second long side (i.e., from the rear toward the
front) when the grate panel is supported on a horizontal
surface.
[0025] For this purpose, the lower side may be realized with a
downwardly protruding projection adjacent to the second long side
(front face) as discussed in the following description of the
figures. In this case, the grate panel in question overlaps the
following grate panel (grate stage), referred to the transport
direction of the material being incinerated, with this
projection.
[0026] However, its front long side preferably ends a certain
distance from the upper side of the ensuing (following) grate
panel, and the outlet opening of the flow channel accordingly lies
above the support surface of the ensuing grate panel. The targeted
air flow against the upper surface of the adjacent grate panel is
favorably influenced in this fashion. This is also discussed below
in the description of the figures.
[0027] Alternatively, it would be possible to arrange the outlet
opening of the flow channel in the lower section of the front long
side. This would result in an air flow that essentially extends
parallel to the upper side of the ensuing grate panel.
[0028] The additional cooling according to the invention makes it
possible to realize the sections of the grate panel that are
situated adjacent to the flow channel thinner than the remaining
sections of the grate panel. This not only lowers the material
requirement, but also improves the cooling effect.
[0029] This "thinner" section is not limited to the front long side
of the grate panel, but may also extend over adjacent sections of
the upper side of the grate panel.
[0030] Grate panels of the aforementioned type have a width (broad
side), for example, of 40-60 cm and a length of several meters. In
this respect, it is also known to realize a grate panel in the form
of several adjacent, interconnected segments that are also referred
to as grate bars. The individual segments may consist of cast
parts, wherein the flow channel can be realized in situ. This means
that each segment is realized integrally. The segments (grate bars)
may also be composed of smaller segments, particularly if they are
welded from sheet metal material. A grate bar may have a width, for
example, of 5-25 cm or more (in the longitudinal direction of the
entire grate panel).
[0031] Adjacent grate bars are interconnected by means of
conventional connecting techniques, for example, with screws or by
connecting several grate bars with the aid of connecting rods. The
thusly formed panels of grate bars can then be interconnected
analogously.
[0032] According to one embodiment, the grate panels are realized
such that at least one recess is formed by two adjacent grate bars
(segments), i.e., each grate bar forms part of the corresponding
recess, for example, one half thereof.
[0033] The invention also pertains to an incineration grate,
particularly a reciprocating incineration grate, with a plurality
of grate panels of the previously described type.
[0034] In this context, the term "reciprocating grate" includes all
types of reciprocating grates, namely regardless of the fact if
they extend horizontally or in an inclined fashion and if the
material being incinerated is conveyed in one or the other
direction. The term "reciprocating grate" also includes conveyor
grates in which, for example, every second grate panel is realized
in a movable fashion, as well as grates in which more than one
stationary grate panel is positioned between two grate panels that
carry out respective movements.
[0035] The invention also pertains to a waste incineration plant,
for example, a garbage incineration plant, with an incineration
grate of the previously described type.
[0036] Other characteristics of the invention are disclosed in the
dependent claims and the remaining application documents. The thus
disclosed features may be essential to the invention in arbitrary
combinations.
[0037] The invention is described in greater detail below with
reference to one embodiment. The respective figures show--in the
form of highly schematic representations:
[0038] FIG. 1, the front sections of two grate panels of a conveyor
grate that lie on top of one another, namely in the form of a
vertical section, and
[0039] FIG. 2, a section along the line A-A in FIG. 1.
[0040] The basic design of a grate panel is described with
reference to the lower grate panel in FIG. 1: the grate panel has
an upper side 10, a lower side 12, a rear long side 14, a front
long side 16 and two broadsides that are not visible due to the
chosen line of section. The upper face area 10o of the upper side
10 is realized in a plane fashion. The second, front long side 16
is angled relative to the upper surface 10o by an angle .alpha.
(approximately 45.degree.) and subsequently angled at 16w.
[0041] Adjacent to the first (rear) long side 14, the lower side of
the grate panel contains a recess 18 that extends in the
longitudinal direction (into the plane of projection), wherein a
round rod 20 lies in said recess and supports the grate panel. The
upper grate panel shown in FIG. 1 can be moved in the direction of
the arrow P with the aid of this round rod 20.
[0042] The lower side 12 of each grate panel is provided with a
plurality of adjacently arranged recesses 22. Each recess 22 is
laterally limited (parallel to the broadsides) by walls, only one
wall 24 of which is visible in the figure. On the rear end of the
grate panel, the recess 22 is limited by a corresponding section
14a of the first long side, wherein the recess is limited by the
front (second) long side 16 on the front end (that points into an
incineration chamber 26). Several cooling ribs 28 protrude from the
wall 24 into the recess 22.
[0043] A wall 30 that essentially has the shape of an arc in said
sectional view transforms into a thickened section 30v at the front
end adjacent to the second long side 16 and also extends between
adjacent walls 24, which thickened section protrudes over a lower
face edge 16u of the second, front long side 16 and forms a support
surface 30u for the grate panels.
[0044] This wall 30 forms a lower (inner) wall of a flow channel 32
that extends from the lower end 16u of the second long side 16
parallel to the wall 30 (such that the inner surface of the long
side 16 forms the other limitation of the flow channel 32) and is
then limited by a lower surface 10u of the upper side 10 before it
opens in the direction toward the lower side 12 of the grate panel.
In the embodiment shown, the wall 30 ends on the lower end of the
recess 22; however, it could also end before the lower end of the
recess. In the embodiment shown, a funnel-shaped inflow opening for
the cooling air results underneath the grate panel, wherein the
cooling air flows against the entire recess 22 including the
section that is situated underneath the wall 30.
[0045] In the upper grate panel shown in FIG. 1, the part of the
cooling air conveyed through the flow channel 32 is symbolized by
the arrow K. This means that the cooling air enters the flow
channel 32 on the funnel-shaped end 32k and is then initially
conveyed along the inner surface 10u of the upper side 10 and then
along the inner surface 16i of the long side 16 before the cooling
air is discharged in the region of the opening 32o and blown onto
the upper side 10 of the adjacent grate panel.
[0046] The supply of additional cooling air is symbolized by arrows
L in the lower portion of FIG. 1.
[0047] The air flowing against the upper side 10 of the grate panel
additionally cools the section situated adjacent to the flow
channel 32 from outside. Deposits (so-called pick-ups) that are
caused by precipitating materials, particularly metals
precipitating from the material being incinerated, and indicated by
the dotted region 34 in FIG. 1 can be prevented in this
fashion.
[0048] The intensified cooling (additional cooling) in the
particularly critical front section of the grate panel makes it
possible to realize the wall thickness of the grate panel thinner
in this section than in the rear section of the grate panel as
shown in the figure.
[0049] For example, the upper side 10 has a thickness of 12 mm in
the rear section 10r and a thickness of only 6 or 8 mm in the front
section (that is situated adjacent to the flow channel 32). This
applies analogously to the wall thickness of the second long side
16.
[0050] In the embodiment shown, the grate panel is composed of a
plurality of adjacently arranged segments that directly adjoin and
are connected to one another. These segments are also referred to
as grate bars.
[0051] FIG. 2 shows that each grate bar T1, T2 forms a wall 24
approximately in its center such that a recess 22 is respectively
limited by two adjacent grate bars T1, T2. This also applies to the
flow channel 32 that has an approximately oval cross section in
this view.
[0052] Bores 36 illustrated in FIG. 1 serve for receiving rods that
are used for interconnecting adjacent segments T1, T2. A grate
panel is composed of a plurality of such segments T1, T2, for
example, 50-60 segments.
[0053] The grate panel shown may be realized in the form of a cast
iron part, wherein each grate bar T1, T2 is realized integrally,
i.e., the ribs 28 and the wall 30, for example, are realized in one
piece together with the wall 24.
* * * * *