Note: Descriptions are shown in the official language in which they were submitted.
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"COKE OVEN BATTERY"
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a coke oven
battery.
DESCRIPTION OF THE PRIOR ART
Coke oven batteries are known having a
plurality of substantially horizontal coking chambers
and an oven roof. The oven roof has a plurality of
vertical conduits e.g. for inspection, for the removal
of coke-oven gas, and for charging the battery. The
majority of the oven roof is constructed from masonry
and the joints between the masonry open and cracks
develop when the coke oven battery is fired and also
during operation of the battery. This leads to the
problem that coke oven gas produced during operation of
the battery leaks from the coking chambers in the
battery to the exterior of the battery or to the
combustion system of the battery through the open
joints and cracks in the roof.
Gas leakage occurs by coke oven gas, formed
during the coking process, leaking into the oven roof
from:
it) the coking chambers,
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(ii) the conduits (usually called "ascension pipes")
in the oven roof for the removal of coke-oven gas;
and/or
(iii) the charging conduits in the oven roof.
Convection of the coke-oven gas causes the
temperature of the oven roof to increase and combustion
of the gas in the roof (such combustion being known as
"inner fires") damages the brickwork. The tie rods
installed in the roof become too hot and the tensile
force they exert decreases, reducing their
effectiveness. The upper parts of the roof usually
contain porous insulation bricks and the hydrocarbons
in the coke-oven gas condense in these bricks, reducing
their insulative effect. Coke-oven gas may also pass
through the roof to the combustion system of the
battery, leading to incomplete combustion and sooting
; of the chimneys. Coke-oven gas leaking to the
atmosphere causes pollution of the environment.
It is also possible for combustion gas to leak
from the combustion system, especially from the
- inspection conduits extending vertically through the
oven roof, into the oven roof itself and from thence to
the atmosphere.
Leakage of coke-oven and combustion gas results
in less efficient and hence less economic performance
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and also makes operation of the battery more difficult.
The leakage results in degeneration of (parts of) the
oven roof making repairs necessary.
As has been mentioned, tie rods are sometimes
provided in the roof, which exert compressive forces on the
; lateral edges of the roof. This may reduce the amount of
gas leakage but its effect is extremely limited and is use-
less in combating localized leaks.
It is known from e.g. Canadian Patent No.
1,178,552 to coat the exterior of the lateral edges of a coke
oven battery with metal foil. Such an exterior coating is
impractical for use on the oven roof as it would be damaged
too easily. It also could not prevent gas leakage from one
part of the battery to another.
SUMMARY OF THE INVENTION
The present invention seeks to eliminate, or at
least reduce, the problem of gas leakage in the oven roof. It
does this by providing a gas-tight screen in the roof. The
screen has substantially horizontal sections extending between
the vertical conduits in the roof, and substantially vertical
sections adjacent the vertical conduits. The substantially
horizontal sections limit the spread of gas from the coking
chambers and the substantially vertical sections limit
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the spread from the conduits. The substantially
vertical sections also help to stop gas leakage to the
combustion systems.
The screen is preferably made of a plurality of
metal sheets.
The substantially vertical sections of the
screen should preferably be designed so that they
extend to a point at or adjacent the top of the oven
roof. In order to prevent leakage from the top of the
screen near the openings of the conduits, the top of
the substantially vertical sections should preferably
be constructed so that they form a gas-tight seal with
mounded bricks which restrict the conduits. This may
be achieved by casting in concrete a stepped portion of
the vertical sections to the mounded bricks.
Where there are a plurality of closely spaced
conduits, a simple screen construction may be obtained
by combining the vertical sections near to these
conduits to form a common vertical screen section.
In order to improve the gas-tight sealing of
the screen, the substantially horizontal sections
preferably comprise two separate horizontal layers
spaced vertically apart.
Where the oven roof consists from bottom to top --
of a number of courses of silica and/or commute
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bricks, and several courses of refractory insulation
bricks, at least the substantially horizontal sections
of the screen should preferably be installed in the
section containing the porous refractory insulation
bricks.
Preferably tie rods are provided in the roof,
such that the screen is between them and the coking
chambers. This prevents gas leaking to the tie rods to
reduce the risk of their tensile stress being reduced
by overheating.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will now be
described, by way of examples with reference to the
accompanying drawings in which:
; 15 Figure 1 it an elevation of a coke-oven battery
on the oven roof
Figure 2 shows a vertical transverse section of
the oven roof according to arrow II-II in Figure l;
Figure 3 shows a vertical longitudinal section
along the line III-III in Figure l;
; Figure 4 shows a vertical transverse section of
the part marked IV in Figure 2, on a larger scale;
Figure 5 shows a vertical longitudinal section
of the part marked V in Figures 3 in a larger scale, --
and
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Figure 6 shows a vertical longitudinal section
along the line VI - VI in Figure 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In Figs. 1, 2 and 3 a coke-oven battery has
horizontal coking chambers 2 and an oven roof 3. The
temperature in the coking chambers 3 during operation
of the battery is approximately 800C. The oven roof 3
is in most cases designed as a brickwork structure, and
is approximately 1 moire thick. Combustion walls 4 are
provided between adjacent coking chambers 2, each wall
4 comprising a number of combustion chambers 5. During
operation, the temperature in the combustion chambers 5
is approximately 1350C. A large number of vertical
inspection conduits 6 are provided in oven roof 3,
which conduits open into the combustion chambers 5. At
; least one ascension conduit 7 for coke-oven gas is
Jo provided in the oven roof 3 for each coking chamber.
In most coke-oven batteries a plurality e.g. four,
charging conduits 8 are also provided in the oven roof
for coking coals. Inspection conduits 6 and charging
conduits 8 are sealed with covers during operation.
During operation coke-oven gas penetrates open
joints and cracks in oven roof 3 (see Figure 2) at arch
; 9, ascension conduit 7 and charging conduits 8, in the
direction shown by arrows 10. This gas seeks an exit
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to the atmosphere through the oven roof, in the
direction of arrows 11, or finds its way, under certain
conditions through the inspection conduits 6 to the
combustion system, as shown by arrows 12. Under other
conditions combustion gas also penetrates the oven roof
at inspection conduit 6 in the direction-of arrows 27,
whereupon the combustion gas also seeks an exit to the
atmosphere in the direction of arrows 11.
In Figures 4 and 5 the present invention is
shown in a common oven roof design, namely one in which
the roof consists of a brickwork structure 13 in which
are provided vertical inspection conduits 6 and
charging conduits 8, formed by mounded bricks 14~ Many
variants of the embodiment of the invention according
to the example are conceivable to the skilled man, all
of which lie within the scope of the present invention.
A gas-tight screen 15 it installed between the
vertical conduits 6, 7 and 8 in the oven roof. The
screen lo comprises substantially horizontal and
substantially vertical sections 17 and 18 respectively
formed from metal sheets 16, the substantially
horizontal sections 17 extend between the conduits, and
the substantially vertical sections 18 are adjacent the
conduits 6,7 and 8.
The metal sheets 16 are installed in the joints
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of brickwork 13. A good structure for example, us one
in which the metal sheets are 0.05-0.25 mm thick, and
consist of oxidation-resistant alloy steel foil, the
material of which has the following composition: 15-30
Or, 5-25% No and 0-10% Mow Sheets of fixed dimensions
or sections which are taken up from a coil, in widths
of 60 or 90 cm, for example, are used for producing
screen sections 17,18. The sheets are installed so
that they overlap.
The sheets can be installed not only when
constructing a new coke-oven battery, but can also be
used in an existing oven roof, after parts of it have
been demolished.
The substantially vertical sections 18 extend
from close to the top of the oven roof. The
substantially vertical sections 18 of the screen 15
prevent gas from penetrating the brickwork, past
vertical screen sections 18 in the direction of arrows
10, at the vertical conduits 6,7,8. The substantially
horizontal sections 17 of the screen 15 prevent the
conveyance to the atmosphere of gas which has
penetrated oven roof 3 from arch 9 of coking chambers
2. The substantially horizontal sections 17 also
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prevent leakage into the atmosphere of gas which is
forced along the bottom of the substantially vertical
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sections 18 of the screen 15 past these sections and
into the brickwork, for example, if these sections are
affected by a high temperature. The substantially
vertical sections close to inspection conduits 6 also
prevent the discharge of gas which has penetrated the
brickwork underneath the substantially horizontal
sections 17 of the screen 15 via the inspection
conduits and into the combustion system.
In order to prevent leakage into the atmosphere
at the top of the conduits 6, 7 and 8 through the
brickwork between the mounded bricks 14 and the
substantially vertical sections 18 of the screen 15,
the substantially vertical sections 18 of the screen
are arranged 80 that they form a gas-tight connection
with mounded bricks 14, by bringing these sections into
contact with the mounded bricks at point 19, and
preferably casting the structure thus formed in
refractory concrete. The mounded bricks at the top of
the vertical conduits are, in most cases, recessed
slightly in relation to the mounded bricks underneath
them. Thus for a gas-tight connection with the top
mounded bricks, a stepped top section 20 of the
vertical sections 18 is desirable. This stepped top
section 20 is considered to form part of the vertical
section 18 of the screen 15, so that these sections 18
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are referred to as substantially vertical sections
although they may not be vertical over their entire
length.
The inspection conduits 6 of a combustion wall
are installed in a row as shown in Figure l in
conventional coke-oven battery design, and are located
close to each other. Although it is possible to
install substantially vertical sections in the oven
roof round each inspection conduit 6 a simple structure
is obtained by combining the substantially vertical
sections close to a row of inspection conduits to form
two substantially vertical sections 21 close to and on
each side of the row of inspection conduits 6.
In the structure according to the invention,
gay which has penetrated the brickwork accumulates
underneath the substantially horizontal sections 17.
The penetration of this gas through one or more
substantially horizontal sections as a result of
defects in those sections will again cause considerable
leakage. Therefore the horizontal screen sections
should preferably be constructed with two separate
horizontal layers 28 of metal sheets, spaced vertically
apart.
In a conventional design, the oven roof
comprises, from bottom to top, firstly a plurality of
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courses of silica bricks 22, close to the coking
chambers 2 and the combustion chambers 5, possibly a
plurality of courses of commute bricks 23 and several
courses of porous refractory insulation bricks 24. As
shown in Figures 4 and S, at least the horizontal
sections 17 of the screen 15 should preferably be
installed in the part of the roof containing the porous
refractory insulation bricks.
The gas-tight screen lo shown in Figure 6 is
basically the same as that shown in Figures 4 and S,
although the screen is of a much simpler design
because between the vertical inspection conduits 6 and
the charging conduits 8 the roof consists substantially
I; of mounded bricks 14 only, so that there is much lest
; lo room available for the screen to be installed in the
roof 3. As before the screen 15 has substantially
; horizontal sections 17 and substantially vertical
sections 18 formed from metal sheets. The screen 15 it
arranged to form a gas-tight connection with the
mounded bricks at the top of conduits 6 and 8.
Furthermore the substantially vertical section 18 of
the screen 15 close to a row of inspection conduit are
combined to form vertical sections 21 close to and on
each side of the inspection conduit.
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The substantially vertical sections 21 shown in
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Figure 6 are arranged to be substantially in line with the vertical parts of the stepped top sections 20 shown
in Figure 5. Likewise the substantially horizontal
sections 17 at the screen shown in Figure 6 are
arranged to be substantially in line with the
horizontal parts of the stepped top sections 20 shown
in Figure 5. In this preferred embodiment of the
screen the tie rods are installed in that section of
the oven roof on the opposite side of the screen 15
from the coking chambers so that the tie rods 25 are
protected from temperature increases due to gas
leakage. The tie rods may be provided with additional
protection against temperature increases by means of
thermal insulating material 26 installed in the
screened section of the oven roof.
In addition the stepped sections 20 of the
substantially vertical sections 18 shown in Figure 5
may be provided with additional vertical parts 29 to
form channels 30 (see Figure 1) for the tie rods 25
which channels extend substantially the entire length
of the tie rods in the roof, the channels consisting of
stepped sections 20 and additional sections 29 in
Figure 5 and of sections 17,18 and 21 in Figure 6
respectively. The additional vertical parts 29 are
also provided with thermal insulating material 26, so
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13.
that the tie rods are fully sealed and insulated from
the oven roof.
