Note: Descriptions are shown in the official language in which they were submitted.
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Centrally Controlled Coke Oven Ventilation System for Primary and Secondary
Air
[0001] This invention relates to a device and a method for supplying
combustion air for the combustion of coking gas in cokemaking chambers of coke
ovens built in flat-type construction and arranged as a battery of coke ovens
for the
so-called non-recovery or heat-recovery process. This device at least
comprises a
vent port for each cokemaking chamber, said vent port extending through the
relevant coke oven door or its wall surrounding it, as well as vent ports for
supplying
secondary air into the heating flues. A freely-supported locking element is
provided
for each vent port.
[0002] All locking elements are mechanically connected to at least
one
adjusting element controlled and driven from a central point. The adjusting
element
continuously actuates the locking elements depending on the demand for
combustion
air in the cokemaking chamber. The mechanical connection of each individual
locking
element with the central adjusting element can be effected separately, wherein
especially the starting position of each individual locking element at the
beginning of
the cokemaking process of the pertaining cokemaking chamber can be adjusted
independently of the other locking elements of the adjacent cokemaking
chambers.
[0003] Heating of heat-recovery ovens is usually performed by
combustion of
gas evolving on cokemaking. Combustion is controlled in such a manner that
part of
the gas above the coal charge burns off with primary air in the oven chamber.
This
partly burnt gas is fed through channels that are also designated as
"downcomers" to
the heating flues in the oven chamber sole and completely burnt there by the
addition
of further combustion air, which is called secondary air.
[0004] In this way, heat is directly supplied from the top and indirectly
from the
bottom to the coal charge, thus taking a positive impact on the coking rate
and,
thereby, on the performance rate of coke ovens. To execute the method it is
required
to exactly rate and variably control the supplied primary and secondary air
throughout
the carbonisation time that may take up to 20 to 96 hours. Heat-recovery and
non-
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recovery coke ovens in flat-type construction are widely described in prior
art
disclosures. For example, reference is taken to US 4,344,820, US 4,287,024,
US 5,114,542, GB 1 555 400 or CA 2 052 177 C.
[0005] According to the conventional state of the art in technology,
primary air
is sucked in from the atmosphere through ports in the doors. Secondary air is
sucked
in through ports near to ground and conducted through channels into the
heating
flues which mainly extend horizontally under the coke oven chamber. The ports
for
primary and secondary air are either opened permanently or provided with flaps
designed to adjust the amount of air to be aspirated.
[0006] As the coke oven batteries are very extensive, and since usually a
very
high temperature prevails therein and because a serious development of dust is
encountered, only manually adjustable ventilation flaps are disclosed in prior
art
technology. US Patent No. 5,928,476 describes such a coke oven battery,
wherein
three manually operable ports are provided in each coke oven door, in which or
in
front of which one plate or disk each adapted to the port cross-section and
supported
at a central axle is arranged. These port flaps can be varied in their
position manually
through levers.
[0007] In practice, however, it becomes evident that the required
variation in
the amount of primary and secondary air throughout the carbonisation time is
effected with a manual adjustment only in very isolated cases and that the
ideal time-
dependent adjustment is thus by far not achieved. Furthermore, manual
operation
implies a serious burden to operators' health.
[0008] Now, therefore, some embodiments of this invention may remedy
the
described deficiencies in an economic manner and to assure an optimised supply
of
primary air and/or secondary air. Operational safety must be assured even with
usually high temperatures and heavy impurities.
[0009] Some embodiments of the invention provide a device for
supplying
combustion air for the combustion of coking gas in cokemaking chambers of coke
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ovens built in flat-type construction and arranged as a battery of coke ovens,
wherein
the venting device consists of at least one vent port for each cokemaking
chamber,
said vent port extending through the relevant coke oven door or through its
wall
surrounding it, and wherein a freely-supported locking element is provided for
each
vent port, wherein
- all locking elements of these vent ports are mechanically connected to at
least one
adjusting element controlled and driven from a central point,
- the locking elements are to be actuated by means of said adjusting element
depending on the demand for combustion air in the cokemaking chamber,
- the mechanical connection of each individual locking element with the
central
adjusting element can be effected separately, wherein especially the starting
position
of each individual locking element at the beginning of the cokemaking process
of the
pertaining cokemaking chamber can be adjusted separately and independently of
the
other locking elements of the adjacent cokemaking chambers.
[0009a] Some embodiments of the invention provide a ventilation device for
supplying primary and secondary air for the combustion of coking gas in
cokemaking
chambers of coke ovens built in flat-type construction and arranged as a
battery of
adjacent coke ovens, which each have one cokemaking chamber with at least one
coke oven door, wherein said ventilation device consists of at least one vent
port per
cokemaking chamber for primary air, said vent port extending through the at
least
one coke oven door or through a wall surrounding it, said ventilation device
furthermore comprising at least one vent port per cokemaking chamber for
secondary
air and wherein freely-supported locking elements are provided for at least
part of
said vent ports, wherein at least a part of the locking elements of said vent
ports is
mechanically connected by connecting elements to an adjusting element that is
controlled and driven from a central point, said locking elements are
actuatable by
means of said adjusting element depending on the demand for combustion air in
the
cokemaking chambers, and the mechanical connection of each individual locking
element with the adjusting element is effected individually, so that the
starting
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positions of the locking elements at the beginning of the cokemaking process
of each
cokemaking chamber are adjustable separately and independently of the locking
elements of the adjacent coke ovens.
[0010] The connection between the locking element and the adjusting
element
as used hereunder shall be understood to mean that both elements may be
connected to each other in a detachable way through a coupling element, for
example a lever, rope tackle, chain, lever arm, etc. as well as combinations
of these
elements.
[0011] Advantageous embodiments provide for configuring the adjusting
element as a rotating chain or as a steel cable. Using a screw spindle as
adjusting
element is another suitable embodiment. All these adjusting elements permit a
permanent actuation into one moving direction which is very advantageous for
the
continuous overall process.
[0012] Furthermore, the device embodying this invention can be
configured in
such a manner that locking plates are installed as locking elements, said
locking
plates being supported in such a way that when actuated by the coupling
element
they are moved mainly in parallel to the oven door.
[0013] For a directed flow of primary gas it is of advantage for the
vent port to
be of a rotary-symmetrical shape. Therefore, the use of locking elements
configured
as upright standing locking plates and supported in vertically or horizontally
rotatable
arrangement around a central axle is advantageous.
[0014] With a further improved embodiment of said ventilation device,
the
locking elements are formed by at least two overlapping and reciprocally
slideable
facettes, with both facettes ideally exposing a polygonal and point-
symmetrical or
nearly circular cross-section when partly opened. Hence, there is no diversion
of
aspirated air in the vent port and because of the higher flow velocity the
aspirated air
is directed more deeply into the oven space.
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[0015] A still advanced improvement resides in configuring the
locking
elements in conical shape, with the tip pointing towards the oven interior
when built-
in. This embodiment can still be further optimised in such a way that the vent
port has
the same or a wider angle of aperture than the pertaining conical locking
elements. In
this embodiment of the locking element for the device embodying this
invention, the
aspirated air is whirled-up minimally in the area of the locking element as
well as in
the area of the vent port and shaped to a gas jet independently of the size of
the
exposed cross-section.
[0016] With a different size of the conical angles of the vent port
and locking
element it can be assured that impurities accumulating in the vent port do not
prevent
a complete closure of the vent port. The conical locking element is moved via
a lever
structure and/or a spindle in the longitudinal direction of the vent port so
that a
circular ring gap is exposed when partly opened.
[0017] The ventilation device can be further improved by connecting
the
locking element with the adjusting element in such a way that it is
automatically
released from the adjusting element when being in the end position and when
the
vent port has been completely closed.
[0018] Another embodiment of this invention furthermore comprises a
method
for supplying combustion air in coke ovens, in which the ventilation device
embodying
this invention as described before is implemented by one of its embodiment
variants,
with the sequence of the method being as set forth below:
a) A ventilation device embodying this invention as described before is
implemented
for the method, and after discharging and recharging the cokemaking chamber
said
locking elements are moved into the starting position that represents the
complete or
nearly complete opening of said vent port, and wherein said locking elements
are
connected to the central adjusting element.
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b) During the carbonisation time, the locking elements are actuated by the
central
adjusting element continuously and mainly at the same medium speed or
actuation
frequency so that the vent ports are continuously closed.
c) Latest at the end of the carbonisation time of a cokemaking chamber will
the
locking elements have completely closed the vent ports of this cokemaking
chamber
and can be released from the adjusting element.
d) Upon discharging and recharging, the method is restarted again by taking
step (a).
[0018a] Some embodiments of the invention provide a method for
supplying
combustion air for the combustion of coking gas in cokemaking chambers of coke
ovens built in flat-type construction and arranged as a battery of coke ovens,
comprising at least one ventilation device, by using at least one ventilation
device as
defined herein, wherein the method comprises the steps: a) the cokemaking
chamber
of an individual coke oven of the coke oven battery is discharged and
recharged for
carbonisation, and after the recharging, locking elements for the vent ports
of the
cokemaking chamber are moved into the starting position that represents the
complete opening of said vent port, and said locking elements are connected to
the
connecting element which is connected to the adjusting element, and
subsequently b)
the coking process starts with a carbonisation time, during which said locking
elements are actuated by the adjusting element such that the vent ports are
gradually
closed, and subsequently c) latest at the end of the carbonisation time of the
cokemaking chamber, the locking elements of the cokemaking chamber have
attained their end position and are released from the adjusting element so
that the
coking process is finished, and subsequently d) the cokemaking chamber is
discharged and recharged, so that said method according to (a) is restarted
again.
[0019] An improved variant of this method is that the locking element being
in
the end position is automatically released from the adjusting element.
[0020] In another improved embodiment of the process embodying this
invention, at least two central adjusting elements are provided for, wherein
one
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adjusting element thereof actuates the locking elements for primary air and
wherein
the other central adjusting element actuates the locking elements for
secondary air.
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Throughout the entire carbonisation time, the two adjusting elements are
controllable
completely independently of each other.
[0021] It is advantageous to actuate one central adjusting element
continuously and mainly at the same speed or actuation frequency.
[0022] This invention also encompasses the use of the ventilation device
embodying this invention in one of the embodiment variants outlined
hereinabove
with a method for supplying combustion air in cokemaking chambers of coke
ovens
built in flat-type construction and arranged as a battery of coke ovens.
[0023] This invention is described by way of three exemplary
embodiment
variants illustrated in FIG. 1 to FIG. 3, with the invention not being
restricted to these
examples of embodiments.
FIG.1 shows a coke oven with a coke oven door in its front view, with two
locking
elements, a connecting element and an adjusting element for primary air and
with
four locking elements, a connecting element and an adjusting element secondary
air.
FIG.2 shows two adjacent coke ovens of a coke oven battery with locking
elements,
connecting elements and adjusting elements for primary air and secondary air.
FIG.3 shows a locking element as an embodiment of the invention for a vent
port of a
coke oven, which is conical, with the tip pointing to the oven interior when
built-in.
[0024] FIG. 1 shows a coke oven 1 in a front view. In its front area,
coke oven
1 has a coke oven door 2 in which two vent ports 3 for primary air are
arranged.
Located beneath said coke oven door 2 and illustrated by dotted lines are
heating
flues 4 extending under the oven space. The vent ports 5 for supplying
secondary air
into these heating flues 4 are arranged near the bottom beneath said heating
flues 4.
[0025] Moreover, FIG.1 shows the locking elements 6 for said vent
ports 3 of
the primary air supply and the locking elements 7 for the vent ports 5 of the
secondary air supply. Each locking element mainly consists of a locking plate
9 and a
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lever arm 10 and it is supported at an axle 8 around which said locking
element can
be moved in rotating motion. The lever arms 10 of said locking elements 6 are
connected in a detachable way with a rotating chain 11 and the locking
elements 7
are connected in a detachable way with a rotating chain 12.
[0026] By a continuous movement of chain 11, the locking elements 6 are
moved in counter-clockwise direction around the angle a while the locking
elements 7
are moved in clockwise direction around angle P. The chains are driven via the
central adjusting elements 13 and 14, respectively.
[0027] FIG.2 shows the front view of two coke ovens 1 representing a
major
coke oven battery as indicated by the two arrows I and II. These two coke
ovens 1
are at different stages of coal carbonisation. The coke oven 1 shown on the
right side
is in the initial stage of coal carbonisation, and therefore the locking
elements 6
hardly overlap the vent ports 3. In this example of the embodiment, the lever
arm 10
is connected via a minor chain 15 to the rotating chain 11. The arrangement in
the
area of the vent ports 5 for secondary air is analogous. Here, the locking
elements 7
and, respectively, their lever arms 10 are connected via minor chains 16 to
the
rotating chain 12.
[0028] The supply of air to the coke oven 1 shown on the left side
has already
been closed completely and the lever arm 10 and the chain 15, respectively,
have
been released from the rotating chain 11. The locking elements 7 for the
control of
secondary air of the coke oven 1 shown on the left side are at a stage shortly
before
closure, but they are not yet closed completely. Hence, it is well conceivable
that
each coke oven 1 can be controlled absolutely individually despite a common
central
control.
[0029] A special embodiment variant of the locking elements 6 and 7 is
illustrated in FIG.3. Shown in this sectional drawing is a rotary-symmetrical
locking
element 6 having a locking head 17 in form of a truncated cone to which a
cylindrical
guiding rod 18 is fastened. The guiding rod is firmly connected to a spring
bridge 19
fastened to said coke oven door 2. The guiding rod 18 is guided in a guiding
tube 20
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and connected with its rear end via a small chain 15 to the rotating chain 11.
At the
beginning of the carbonisation time, the springs of the spring bridge 19 are
pre-
stressed by expansion so that the vent port 3 is largely open. By the movement
of the
rotating chain lithe spring bridge 19 is relieved, the locking element 6 is
moved in
the direction of the coke oven door 2, and the locking head 17 is introduced
into the
conical vent port 3. The pre-stressing shall be chosen such that after relief
of the
chain 15 and spring bridge 19 a complete closure of vent port 3 is achieved.
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List of Reference Numbers:
1 Coke oven
2 Coke oven door
3 Vent port (primary air)
4 Heating flues
5 Vent ports (secondary air)
6 Locking elements (primary air)
7 Locking elements (secondary air)
8 Hinge
9 Locking plate
10 Lever arm
11 Chain (primary air)
12 Chain (secondary air)
13 Adjusting element
14 Adjusting element
15 Chain
16 Chain
17 Locking head
18 Guiding rod
19 Spring bridge
20 Guiding tube
