EP0065328A2

EP0065328A2 - A method of repair of a coke-oven battery, and a panel for use in the method

Info

Publication number: EP0065328A2
Application number: EP82200525A
Authority: EP
Inventors: Hermanus Johannes Dries; Floris Blaas; Jan Klootwijk; Peter Stephanus Snijders; Bernardus Antonius Wijnandus Van De Vegt
Original assignee: Hoogovens Groep BV
Current assignee: Tata Steel Ijmuiden BV
Priority date: 1981-05-11
Filing date: 1982-05-03
Publication date: 1982-11-24
Also published as: DE3264884D1; EP0065328A3; EP0065328B1; CA1218332A; NL8102281A

Abstract

A coke oven battery is repaired, during operation, by creating a screened-off working space which extends over at least part of one or more coking chambers. To this end, insulating material is applied against the side-walls of the chamber or chambers so that they remain at a relatively high temperature, to reduce the risk of crack formation on cooling. Repair is effected from the screened-off space. To improve the working conditions in this space, in particular to reduce the temperature to near room temperature, the insulation includes one or more panels which have a layer of insulating material and ducts through which cooling fluid, e.g. water, is passed.

Description

The invention relates to a method of repair of a coke-oven battery during operation in which at least one coking chamber is taken out of operation and emptied, is repaired and reintroduced into operation. The invention also relates to a panel for use in the method.
A coke oven battery of a type conventional in practice consists of a structure made of refractory material with coking chambers arranged within it. A plurality of combustion chambers are arranged between each adjacent pair of coking chambers. The coking chambers generally each measure approximately 45cm wide, 4 to 6 m high and about 10 m long. The side walls of the coking chambers are generally made of silica bricks. The overall coefficient of expansion of the silica material is such that the material has about 1% expansion from room temperature to 500°C, and a further expansion of around 0.1% from 500°C to the operating temperature, which is around 1200°C.
Silica's expansion characteristic makes it an ideal material when the battery is in operation, because when the coke is pushed out at the end of the coking period and the coking chamber is subsequently refilled with coking coal, the temperature of the refractory material undergoes a temporary reduction without falling. below 500°C, which means that the refractory material only contracts and expands to a slight degree. This means that cracks do not readily form.
These temporary reductions in temperature do however cause hairline cracks which, in the case of the side walls of the coking chamber, expand in the course of time to form larger and deeper cracks. These cracks are a cause of gas leakage between the combustion chambers and the coking chambers.
When repairing a coking chamber, for instance the cracks in the side walls thereof, it is necessary to work inside the coking chamber. For this purpose, the temperature of the coking chamber needs to be greatly reduced, which means entering the temperature range below 500°C in which the silica material undergoes substantial contraction. This causes fresh and larger cracks in the side walls. Through these cracks, there will be further gas leakages between the combustion chambers and the coking chamber, when the chamber is brought back into operation, and in extreme cases the stability of the side walls may be endangered.
It has been proposed to line the walls of a coking chamber, which is to be repaired, with insulation, in order that a person may enter it while the battery remains in operation. See US 2 179 635, DE 2 274 552 and DE 2 112 729. This practice is not wholly satisfactory, because the temperature of the working space remains uncomfortably high. The worker has to wear insulating clothes, which is very inconvenient in the confined space. Intensive ventilation of the space is needed, in order to reduce the temperature of the air which the worker breathes. Furthermore, in practice, it is found that reduction of the firing in adjacent combustion chambers is needed. The insulation layer may be rather thick (e.g. 7.5cm as disclosed in US 2 179 635, reducing the room available for working.
The invention has as its object to provide a method of repair of a coke-oven battery during operation in which the conditions for the worker in the insulated coking chamber are improved, and particularly in which the temperature of the air in which he works approaches room temperature.
According to the present invention, the insulation material includes at least one panel which comprises a layer of thermally insulating material and ducts through which cooling fluid is passed during the repair operation. The panel is located against a side-wall of a coking chamber, with the insulating layer adjacent the wall and the ducts on the inside with respect to the working space.
The combination of an insulating layer and cooling by means of a fluid is a considerable improvement over the prior art proposals. In this way it is possible to reduce the temperature in the working space to for example 20°C, while the side-wall temperature remains above 500°C, and yet leave sufficient room within the chamber for the worker to carry out the necessary repairs. Working conditions are improved because insulating clothing and forced air ventilation are not required. It is also not necessary to reduce the degree of firing in neighbouring combustion chambers, so that thermal disturbance of the coke-oven battery is reduced.
Fluid cooling is known in a screen providing protection for workmen (see US 3 550 679). However it is the combination of an insulating layer and fluid cooling which is surprisingly effective in the present invention, and can achieve about room temperature in the working space even with a relatively thin panel (e.g. 5cm).
There are various possible ways of using the panels to create the screened-off space. For example, several panels may be positioned alongside one side wall. It is also possible for one panel only to be positioned alongside one side wall. One or more panels may be used to create a screened-off space without being positioned alongside a side wall. Insofar as the working space is not screened off from the hot coking chamber walls by means of panels, this may for example by effected with blankets of insulating material or the like.
In many cases, the repair affects one coking chamber only. It is then preferable to create a screened-off space inside the chamber using panels positioned alongside both hot walls of the chamber. When it is necessary to repair the side walls between more than one coking chamber however, the screened-off space should preferably be created in two or more adjacent coking chambers and the panels positioned alongside the two outermost side walls of the group of adjacent coking chambers.
Where the refractory material of the side walls is silica, it is preferable for the temperature of each side wall alongside which a panel is located to be maintained at a minimum of 500°C.
One possible way in which the method may be executed consists of moving the screened-off space within the coking chamber during the repair operation. For this purpose it is proposed more specifically that the screened-off area is movable longitudinally in the coking chamber.
The panel used in the method of the invention is preferably provided with at least one working opening through which work on the wall behind can be performed. Preferably each opening of this type is capable of being closed individually.
In view of the relatively small width of a coking chamber, the area in which the repair is effected may be narrow. In order to have as much space available as possible, the preferred choice for the cooling fluid is water, which will serve to minimise the thickness of the screen. The use of the insulating layer, outside the water carrying ducts, minimises the risk of contact of the water with the hot walls of the chamber.
Preferably the panel ducts comprise a number of parallel pipes, which may be rigidly linked together by connecting elements. In order to keep the panel as thin as possible, the pipes are preferably rectangular in cross-section. The connecting elements may also be rectangular in cross-section and these elements may be connected to the ducts by means of welding.
One useful form of panel has a U-shape, such that one face of the panel has mutually opposed regions.
Preferred embodiments of the invention will now be described by way of non-limitative example and with reference to the accompanying drawings, in which:-

Fig. 1 is a graph showing the relation between expansion and temperature for the material silica.
Fig. 2 shows a coke-oven battery in the course of repair by a method embodying the invention, in horizontal cross-section on line II-II in Fig. 3.
Fig. 3 is a vertical cross section on line III-III in Fig. 2.
Fig. 4 shows a battery in the course of repair by a second method embodying the invention, in horizontal cross-section on line IV-IV in Fig. 5.
Fig. 5 is a vertical cross-section on line V-V in Fig. 4.
Fig. 6 shows a battery in the course of repair by yet another method of the invention, in a horizontal cross-section on line VI-VI in Fig. 7.
Fig. 7 is a vertical cross-section on line VII-VII in Fig. 6.
Fig. 8 illustrates a panel of the invention for use in the repair of a coke-oven battery.
Fig. 9 is. a side view of the panel of Fig. 8, as indicated by arrow IX in Fig. 8.
Fig. 10 is a cross-section of the panel of Fig. 8 on line X-X in Fig. 8.
Fig. 11 shows a panel of the invention for use in the repair of a coke-oven battery by the method shown in Fig. 6.
Fig. 12 illustrates the drop in temperature from a side wall to a coking chamber when using a panel of the invention.

The graph of Fig. 1 shows a typical expansion of the material silica as a percentage along the vertical axis, and the temperature in C along the horizontal axis. Once the material is brought up to a temperature of 500°C, the expansion does not exceed 0.1% over an extensive temperature range above 500°C. When the temperature drops below 500°C, substantial contraction of the material occurs, which has proved capable of producing cracks in the side walls of the coking chambers of a coke-oven battery made of thin material.
The repair of a coke-oven battery by the invention may involve a variety of different arrangements, a number of which are presented in the following examples. The same reference numerals are used throughout for corresponding parts.
Figs. 2 and 3 illustrate an extensive repair to a coke-oven battery. The coking chambers 1 of a part of a coke-oven battery 2 are in a refractory material structure which also comprises the combustion chambers 3. The coking chambers are bounded by their side walls 4, and are closed during charging of the coking coal and coking period by means of doors 5. In the course of time, predominantly vertical cracks develop in the side walls, above all in the vicinity of the doors. These cracks may give rise to leakage of gas between one or more combustion chambers and a coking chamber. Fig. 2 illustrates a situation where the side walls of two adjacent coking chambers are so severely cracked that a part 6 of the refractory-material structure between them needs to be demolished and replaced by a new structure.
Figs. 4 and 5 illustrate a different repair operation, in which the cracks or other faults which have occurred in the side walls 4 of a coking chamber 1 may be repaired by injecting refractory material.
Finally, Figs. 6 and 7 illustrate a special repair. The combustion chambers 3 are supplied with air and gas through the floor 7 via supply ducts 8. These ducts may be blocked by fallen parts of the refractory structure in which the combustion chambers are arranged, so that combustion cannot take place in the combustion chambers, which means that no heat is supplied to the adjacent coking chambers, and hence coking does not take place at the point where the combustion chamber is located.
In each of these repairs, a space screened-off from the hot coke-oven walls is created, in accordance with the invention, using one or several panels 10.
Figs. 8,9 and 10 illustrate a suitable panel design. The area available for repair purposes in a coking chamber is greatly restricted by its minimal width. The flat panel of the invention has ducts 11 for the passage of a cooling fluid and is provided with a layer of insulation material on one side 12. The pipes 13 used for the ducts 11 in this embodiment are rectangular with a cross-section of, for example 25 x 50 mm, welded together in a parallel arrangement using cross-connecting elements in the form of pipes 14 which are likewise rectangular in cross section, measuring, for example 20 x 20 mm.
The preferred coolant is water. Although its choice as cooling fluid is not obvious in view of the risk of it leaking into the coking chamber which is still hot, water is preferred because of its high specific heat and high coefficient of heat, which enables the cross-section of the ducts to be minimised.
The preferred material for the insulation layer is a blanket of ceramic fibre with a high insulating value, such as for example Triton (trade mark) Kao-Wool, mainly consisting of A1 ₂0₃ and Si0₂measuring 25 mm thick.
These measures enable a thin panel to be produced.
In the panel illustrated, the cooling fluid is supplied through supply pipe 15 to a supply duct 16 and, after passing through the ducts 11, is discharged via an outlet duct 18 and an outlet pipe 19. The supply duct 16 and outlet duct 18 are separated from one another by a partition 20. The pipes 13 are connected to the ducts 16 and 18 and the casing 17 by welding. For design reasons, the connecting pipes 14 do not, however, run right through to the ducts 16 and 18 and the casing 17 at the point 20a.
Figs. 2 to 7 show the repairs being effected by a person 27 in a space 26 screened off from the hot coke oven walls which has been created by using at least one panel 10 of the type illustrated in Fig. 8.
In the repair shown in Figs. 2 and 3, two panels 10 are positioned alongside the respective outermost side-walls 4 with the layer 12 of insulating material on the side of the panel 10 which faces towards the side walls. These panels extend the full height of the side walls. The parts of the two coking chambers which are not being repaired are partitioned off by temporary walls 22 covered with insulation material 25. Much thicker and therefore less vulnerable walls are formed by the oven roof 23 and generator roof 24. This serves to create a screened-off space 26 in which the worker 27 can demolish and relace the part 6 of the refractory material. structure.
In the repair shown in Figs. 4 and 5, a similar screened-off space 26 is created in a single coking chamber. In this case, however, one panel 28 has a working opening 29 which may be closed by a door 31 which pivots on an axis 30. A person 27 in the screened-off space 36 may thus carry out repair through the opening 29, e.g. using injection techniques. The panel or panels may contain several of these working openings which as desired may or may not be capable of being closed. Provision is made for the screened-off space to be moved within the coking chamber. In this instance it is proposed more specifically that the screened-off area be moved in a horizontal direction longitudinally of the chamber as indicated by arrows 32.
In the repair shown in Figs. 6 and 7, the side walls 4 are covered for part of their height by a panel 10 and a panel 28 with a working opening 29. The top and bottom boundaries of the working space 26 are constituted by a panel 33 of the design shown in Fig. 11, which contains pipes 13 and 14 as shown in Fig. 8 but these are bent in this case into a U shape to form a U-shaped panel 33, which is provided with a layer 12 of insulation material on the outside.
The screened-off space 26 (see Figs. 6 and 7) formed by the panels 10,28 and 22 may easily be moved within the coking chamber in the direction indicated by the arrows 32 for instance using rollers or rails as shown at 34. In order to keep the side walls above the screened-off space 26 at a sufficiently high temperature, an insulation partition is temporarily fitted in the door opening to the coking chamber above the screened-off space. During the repair operation, a person 27 in the space 26 takes a part of the refractory structure, e.g. a brick, out of the side wall through the working opening 29, thus enabling the combustion chamber to be cleaned, after which the repair opening 35 made in the side wall is closed again. After this, it is possible to clean another combustion chamber by moving the screened-off space within the coking chamber until the working opening reaches the point where the next combustion chamber is located. It should be noted that in this case, the panels 10,28 and 33 used to form the screened-off area 26 lend themselves to being joined together outside the coke-oven battery in advance to form a screen 9 which may be installed inside the coking chamber in its entirety following emptying of the chamber. This enables the time required for the repair operation to be kept to a minimum. A screen 9 of this type may be kept permanently available for repairs.
Fig. 12 illustrates the drop in temperature 36 from a side wall 4, through a panel 10 positioned alongside this side wall, to a coking chamber. The dimensions of the panel and the extent of the cooling action of the fluid in the cooling duct system 11 are such that the conditions created on the side of the panel facing away from the side wall 4 in the working space 26 are suitable for personnel to carry out repair operations therein. If additionally necessary, the area is ventilated. The major part of the temperature drop occurs in the layer of insulation material 12. The surface temperature of side wall 4 is at least 500°C. This protects the side wall from the adverse effects of the excessive cooling.

Claims

1. A method of repair, during operation, of a coke-oven battery having coking chambers (1) with refractory side walls (4), wherein a screened-off working space (26), which extends over at least part of at least one coking chamber is created in the battery by means of thermal insulation material (10,12) applied against side-walls of the coking chamber or chambers so as to maintain those side-walls at a high temperature while the temperature in the working space is reduced sufficiently to allow the repair work to be performed,
characterised in that:

the said insulation material includes at least one panel (10) which comprises a layer of thermally insulating material (12) and ducts (13) through which cooling fluid is passed during the repair operation.

2. A method according to claim 1 wherein the cooling fluid passed through the panel (10) is water.

3. A method according to claim 1 or claim 2 wherein the said insulating layer (12) of the panel is applied against the side-wall (4) of the coking chamber and the said ducts (13) are located on the inside of the insulating layer (12) (with respect to the working space (26)).

4. A method according to any one of claims 1 to 3 wherein said working space (26) is within a single coking chamber, respective said panels being applied to the opposed side-walls (4) thereof.

5. A method according to any one of claims 1 to 3 wherein the said working space (26) extends over a plurality of neighbouring coking chambers, said panels (10) being applied to the respective outermost side-walls of those chambers.

6. A method according to any one of claims 1 to 3 wherein the refractory material of the side-walls (4) is silica, the temperature of the side-walls bounding said working space (26) being maintained at at least 500^oC..

7. A method according to any one of the preceding claims wherein, during the repair operation, the working space (26) is displaced within a coking chamber, by movement of the insulation material (10,12).

8. An insulating panel for use in a method according to any one of the preceding claims characterised by a system of ducts (13) for passage of cooling fluid through the panel (10) and a layer of insulating material (12) arranged on one side of said system of ducts (13).

9. A panel according to claim 8 having at least one working aperture (29) through the panel (10), through which a repair operation can be effected.

10. A panel according to claim 9 having means.for closing the or each working opening (29).

11. A panel according to any one of claims 8 to 10 wherein the ducts (13) are of rectangular cross-section.

12. A panel according to any one of claims 8 to 11 which is U-shaped, so that one face thereof has mutually opposed portions (Fig. 11).