Centrally Controlled Coke Oven Aeration System for Primary and Secondary Air

Abstract

This invention relates to a ventilation device for non-recovery coke ovens, said ventilation device consisting of at least one vent port extending through the wall or built-in internals, e.g. a coke oven door, and connecting the oven interior with the outer atmosphere surrounding said oven and wherein said vent port can be closed entirely or partly by means of a locking element. Two locking elements or more are coupled to each other by at least one mechanical coupling element by fastening said coupling element to said locking elements directly or via a lever, and wherein each coupling element is connected to at least one central adjusting element such that said locking elements can be moved, with it being possible for the relevant vent ports to be closed, completely opened or moved into any intermediate position. Ideally this coupling element should be a chain or a screw spindle.

Description

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.

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.

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.

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-recovery coke ovens in flat-type construction are widely described in prior art disclosures. For example, reference is taken to U.S. Pat. No. 4,344,820, U.S. Pat. No. 4,287,024, U.S. Pat. No. 5,114,542, GB 1 555 400 or CA 2 052 177 C.

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.

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. U.S. Pat. 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.

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.

Now, therefore, it is the objective of this invention to 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.

This invention solves this task by providing a device 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, 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.

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.

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.

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.

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.

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.

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.

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.

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.

This invention furthermore comprises a device 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) After discharging and recharging a 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.
• 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).

An improved variant of this method is that the locking element being in the end position is automatically released from the adjusting element.

In another improved embodiment of the process embodying this invention, at least two central adjusting elements are provided for, wherein one adjusting element thereof actuates the locking elements for primary air and wherein the other central adjusting element actuates the locking elements for secondary air. Throughout the entire carbonisation time, the two adjusting elements are controllable completely independently of each other.

It is advantageous to actuate one central adjusting element continuously and mainly at the same speed or actuation frequency.

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.

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 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.

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 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.

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 β. The chains are driven via the central adjusting elements 13 and 14, respectively.

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.

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.

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 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 11 the 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.

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

Claims

1-17. (canceled)

18. 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 coke ovens, wherein said ventilation device consists of at least one vent port per cokemaking chamber for primary air, said vent port extending through the relevant coke oven door or through its 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, comprising

at least part of the locking elements of said vent ports is mechanically connected to an adjusting element controlled and driven from a central point,

said locking elements can be actuated by said adjusting element depending on the demand for combustion air in the cokemaking chambers,

the mechanical connection of each individual locking element with the central adjusting element can be effected individually, 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.

19. A ventilation device according to claim 18, wherein at least part of the locking elements for primary air is mechanically connected to an adjusting element and wherein at least part of the locking elements for secondary air is mechanically connected to another adjusting element.

20. A ventilation device according to claim 18, wherein the adjusting element is a rotating chain.

21. A ventilation device according to claim 18, wherein the adjusting element is a screw spindle.

22. A ventilation device according to claim 18, wherein the locking elements are locking plates which are supported such that they are moved mainly in parallel to the oven door when they are actuated by the connecting element.

23. A ventilation device according to claim 18, wherein the locking elements are upright standing locking plates supported in vertically or horizontally rotatable arrangement around a central axle.

24. A ventilation device according to claim 18, wherein the locking elements are formed by at least two overlapping and reciprocally slideable facettes, wherein both facettes ideally expose a polygonal and point-symmetrical or nearly circular cross-section when partly opened.

25. A ventilation device according to claim 18, wherein the locking elements are conical, with the tip pointing to the oven interior when built-in.

26. A ventilation device according to claim 25, wherein the vent port has the same or a wider angle of aperture than the pertaining conical locking elements.

27. A ventilation device according to claim 25, wherein the conical locking element can be moved in the longitudinal direction of the vent port, thereby exposing a circular ring gap when partly opened.

28. A ventilation device according to claim 18, wherein the locking element is connected to the adjusting element such that when being in the end position and when the vent port has been completely closed, it is automatically released from the adjusting element.

29. 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, wherein at least one device according to claim 18, is implemented, wherein

a) after discharging and recharging a 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, and wherein subsequently

b) during the carbonisation time said locking elements are actuated by the central adjusting element(s) such that the vent ports are more and more closed, and wherein subsequently

c) the locking elements of a cokemaking chamber have attained their end position latest at the end of the carbonisation time of the relevant cokemaking chamber and are released from said adjusting element, and wherein

d) said method according to (a) is restarted again.

30. A method according to claim 29, wherein after the complete closure of the vent port the release of said locking elements from the adjusting element is effected automatically.

31. A method according to claim 29, wherein throughout the entire carbonisation time the central adjusting element is actuated continuously and mainly at the same medium speed or actuation frequency.

32. A method according to claim 29, wherein at least one central adjusting element for the locking elements of primary air and at least one central adjusting element for the locking elements of secondary air are provided for.

33. A method according to claim 32, wherein the central adjusting element for primary air and the central adjusting element for secondary air are actuated continuously throughout the entire carbonisation time and mainly at the same medium speed or actuation frequency.