WO1989003868A2

WO1989003868A2 - Chamber frame

Info

Publication number: WO1989003868A2
Application number: PCT/EP1988/000938
Authority: WO
Inventors: Wolfgang Becker; Klaus Kaewert
Original assignee: Still Otto Gmbh
Priority date: 1987-10-22
Filing date: 1988-10-19
Publication date: 1989-05-05
Also published as: EP0383813B1; EP0383813A1; DE3821845A1; WO1989003868A3; DE3821845C2

Abstract

Condensate formation is prevented by maintaining a temperature of 500 to 600°C in the sealed gap between the chamber frame (4, 15) and the door of a coke oven.

Description

Chamber frame

The invention relates to a coke oven with heating ducts lying in the masonry, with door frames which are embedded in the coke oven masonry and with coke oven doors.

Coke ovens are heated indirectly. That the side walls of the coke ovens are heated by heating trains which are arranged in the coke oven walls and are gas-fired. The heating cables are at a certain distance from the furnace heads. This is to avoid excessive heating of the furnace heads.

The support surfaces for the coke oven doors are formed by chamber frames on the furnace heads. In the past, the chamber frames mostly had an L-shaped profile. In recent times, the chamber frames have become increasingly thicker and almost square in cross-section. Contemporary chamber frames usually consist approximately of profiles with edge lengths between 150 and 200 mm. Such chamber frames are cast like the previous L-shaped frames.

The thickening of the chamber frames is intended to counteract the thermal deformation. In some cases this is an erroneous assumption, because the temperature difference between the stone-touching chamber frame surface and the most distant coke chamber frame surface is also responsible for the heat deformation. Occasionally, due to temperature fluctuations on the chamber frame, such a play between the sides in contact with stone and the chamber frame surfaces can be observed that leakage points occur which have to be plugged. That is, sealant is stuffed or injected into the gap that opens. j -

devices have held up to this day. There are newer proposals for the design of coke oven doors as described in German Offenlegungsschrift 33 27 337, which significantly increase the cleaning intervals. However, the question of cleaning still arises.

The object of the invention is to avoid cleaning. The invention is based on the idea of preventing the formation of condensate. From European patent specification 0 031 526 a proposal is known to create a closure system on the coke oven which is intended to largely prevent contamination of the closure parts, in particular the sealing surfaces of the door frame and the associated seals, by the formation of condensate and graphite. This effect should be achieved by a hot part designed as a hollow body, which keeps the temperature in the area of the closure above the condensation temperature during the filling and coking process. The hot part is supposed to be a hollow body which is filled with heat-storing and heat-releasing material and is fastened to the coke oven door. The hot part is removed from the oven with the coke oven door to press the coke or with the coke oven door after pressing the coke to refill the oven with the coke oven door. After being reinserted, the hot part should partially radiate against the chamber frame or the closure. The main radiation should, however, be directed towards the gas collection space or gas channel. There are also various views on the importance of the chamber framework. One view sees the chamber frame as a necessary component for the connection of the masonry. The chamber frame should hold the refractory bricks together by pressing. Another view is that the bond between the refractory bricks is guaranteed even without the chamber frame. This also contributed to the adherence to the thick chamber frame profiles.

The chamber frames together with the coke oven doors form sealing surfaces on the coke oven. These sealing surfaces have been the problem areas on the furnace for years. Leakage occurs there. Raw gas escapes. There have therefore been a number of proposed solutions for the sealing between the door frame and coke oven doors. In the past, the so-called hammer blow bar, as is known, for example, from German patent specification 25 48 923, has particularly prevailed from these proposals. These are steel strips that are pressed against the door frame with a sharp edge. The strips can be adjusted along their length with corresponding devices at different locations on the cast door body. A disadvantage of the known strips is the wear effect on the chamber frame. Over time, the strips work their way into the contact area of the chamber frame. It also shows that incrustations build up in the area of the sealing strips. These incrustations can be identified as raw gas components. The condensate contaminates the sealing surfaces and builds up under the strips so that the strips cannot come into close contact with the chamber frame. This must be counteracted by cleaning the chamber frame and cleaning the sealing strips. The cleaning - ά -

It is not clear how the hot part will heat up. A heating device is not provided in the hot part. In this respect, the hot part would have to rely on absorbing and storing the necessary heat during the coking process in order to then be able to release this heat when the door is reinserted. Various problems arise for this proposal. The one problem is the question of the temperature level. It is unclear how a temperature level in the gas duct between the door plug and the coke oven door body is to be generated, which is sufficient for the desired heating of the hot part. It is also open what dimensions and which material properties the hot part must have in order to absorb the necessary heat and to release it again when it is used. The critical situation of this proposal is clear in comparison with the ceramic stopper provided in the known door. The ceramic stopper is exposed to a much higher temperature level than the hot part. Accordingly, it absorbs much more heat than the hot part with the same properties (for the hot part, a ceramic composition is expressly stated to be particularly advantageous). been. Compared to the temperature level and the heat content of the ceramic stopper, the temperature level and heat content of the hot part appear modest.

If experience is now gained with conventional ceramic plugs, in which condensate deposits accumulate to a considerable extent and lead to the problems explained at the outset, the avoidance of condensate formation is not to be expected from the additional hot part provided according to European Patent 0 031 526. Accordingly, no application of the hot part, the proposal of which goes back to 1979, has become known. According to the invention, the surface temperature in the sealing gap is raised to at least 300 ° C. in that the distance of the sealing gap from the first heating train is shortened by at least 130 mm compared to conventional coke ovens and / or the chamber frame is let into a slot in the masonry with a web. The distance is preferably selected or the web in the slot provided extends so deep into the masonry that the temperature in the sealing gap is between 400 ° C. and 600 ° C. In contrast to the solution known from European patent specification 0 031 526, the invention actually prevents the formation of condensate on the sealing surfaces. The shortening of the distance to the first heating train brings the sealing surfaces closer to the hot furnace zone. Alternatively, heat is conducted from the hot furnace zone to the sealing gap via the web.

Conventional coke ovens have a distance between the sealing surfaces to the chamber frame / coke oven door from the first heating train that is between 300 and 340 mm. With this distance it must be taken into account that the chamber frame with a rectangular profile has an edge length of 175 mm, for example. The reduction in the distance according to the invention can be achieved simply by replacing the existing chamber frame with a new chamber frame which, for example, only has an edge length of 50 mm or a thickness of 50 mm. This results in a plate-like chamber frame according to the invention. The plate-like chamber frame is preferably also installed in this form. This can be achieved using the existing clamps by attaching cams, spacers or trestles to the chamber frame in the area of the clamps, which bridge the distance between the plate-like chamber frame and the clamps. Optional cams or other trestles are also provided on the plate-like chamber frame for screwing in the locking hooks. The locking hooks can also be attached directly to the plate-like chamber frame.

On conventional coke ovens with an L-shaped chamber frame, the distance according to the invention from the first heating flue can also be achieved using the existing chamber frame by removing the masonry on the furnace head accordingly.

In any case, it is advantageous if a compensation layer is provided between the chamber frame arranged according to the invention and the masonry. The leveling layer is intended to ensure that the masonry clings to the chamber frame and vice versa. This ensures optimal heat transfer for increasing the temperature in the sealing gap according to the invention.

The chamber frames used according to the invention can consist of heat-resistant or heat-resistant steel. Highly heat-resistant steels have a high alloy content of chrome and nickel. However, such steels are difficult to obtain in the form intended. This applies in particular to a manufacturing process envisaged according to the invention by cutting or burning out the chamber frame from a steel plate. With such a production, welds between the longitudinal and transverse bars of the chamber frame are avoided. Another aspect to consider with high-temperature steel is its thermal expansion, which is many times greater than the thermal expansion of other steels. According to the invention, the thermal expansion of the chamber frame is taken into account in that the chamber frame is manufactured with a pre-calculated undersize in the cold state and then expands to the desired dimension in the operating state. The basis of the precalculation is the temperature difference between the processing or manufacturing temperature and the operating temperature in conjunction with the elongation per degree of temperature.

Nevertheless, a so-called boiler steel is preferably used - these are steels which are used on firing boilers. Such steels are less heat resistant, but they have several advantages. In addition to a price advantage, this also includes the availability of plates from which chamber frames according to the invention can be cut out or burned out.

A cast frame would not be able to withstand the temperature load according to the invention.

When the high sealing gap temperature is achieved according to the invention, the door stopper can remain in the oven in its originally intended or usual position. This position is characterized by the distance to the first (machine side) and last (coke side) heating train. This distance ensures sufficient cooking of the furnace head. Lightweight door plugs are preferably suitable. Such lightweight door plugs have the shape of a shield. The shield can be made of metal or ceramic. The special temperature in the sealing gap provided according to the invention and the resulting heat deformations are taken into account by using a highly flexible coke oven door. Such a door consists, for example, of a profile that bulges outwards, which adapts to the edge region of each chamber frame shape. The adaptation is achieved by a large number of pressure elements which are arranged in a frame which runs around in the area of the sealing gap. The pressure elements preferably have springs which ensure a predetermined pressure on the chamber frame even in the event of thermal expansion and the associated bending of the door body. With such a door, even greater thermal deformations can be taken into account.

According to the invention, it is also preferably provided that the curvature of the coke oven door extends beyond the frame surrounding the sealing area. With such a bulge, an advantageous, very large gas channel can be realized behind the door plate in the coke oven door. It is advantageous to combine this structural measure with two further features. One feature is a layer thickness limited to a maximum of 40 mm for the insulation in the coke oven door or an insulation arranged on the outside of the door. For external insulation, the door body is also made of heat-resistant steel. This results in a recess in the door body. This means that the insulation bulges outwards like the coke oven door. This is new compared to conventional insulation. The second feature is a new type of locking. Due to the arching or bulging of the coke oven door according to the invention, conventional locks can no longer be used. The locks would have to reach around the bulge if the large gas channel is to have a constant cross section over its entire length. Otherwise the gas channel would have to be constricted in the area of the locking hooks and the bulge interrupted.

The new type of locking can be implemented in different ways. An older solution suggests the arrangement of sprockets on the screws, bolts or springs causing the contact pressure in the frame surrounding the sealing gap. The chain wheels are moved together with a common chain in the peripheral frame, the peripheral frame finding an abutment on overlapping locking hooks. The chain wheels can also be coupled to one another in another way. Instead of the sprockets, pneumatically or hydraulically operated cylinders are also suitable as adjusting means for the bolts or springs.

Alternatively, instead of conventional two-armed locking bodies, one-armed locking bodies can be used, which are arranged as swivel arms on the frame and engage behind conventional locking hooks on the chamber frame. The arms of the locking body can then be connected to one another via linkage, with a linkage being provided for each door side and optionally the linkage on both sides being connected to one another via a common linkage at the upper end and / or at the lower end of the coke oven door. Optionally, instead of the individual swivel arms on the circumferential frame, a push rod with protruding wedge-shaped arms is provided, which ^" slide under a shift in the longitudinal direction of the longitudinal spars of the circumferential frame under the locking hooks arranged on the chamber frame and ensure the desired pressing of the coke oven door on the chamber frame.

A coke oven door situation according to the invention is shown in FIG. The illustration is a section which is limited to one half of a symmetrically designed coke oven. With 1 the interior of the furnace is designated, with 2 the masonry made of refractory bricks, with 3 the first (machine side) or last (coke side) heater. The front of the coke oven has a chamber frame 4 with a rectangular cross section, which is embedded in a corresponding recess in the masonry 2. The chamber frame 4 is pressed with a clamp 5 against the masonry 2. The clamps 5 are held on a wall protection plate 6.

In contrast to conventional chamber frames, the chamber frame 4 is provided with a web 20 with which it projects into a groove 21 in the furnace masonry. In the exemplary embodiment, the web 20 has a thickness of 20 mm and a web height of 60 mm.

The oven of Figure 1 is closed with a coke oven door, which consists of a sheet 7. The sheet 7 has an outward bulge, which is filled with insulation material 8. At the edge 9, the sheet 7 is pressed against the chamber frame 4. A sealing material, preferably attached to the edge 9, is provided between the edge 9 and the chamber frame. The pressure on the edge 9 is brought about by a circumferential frame 10 which finds an abutment on the chamber frame 4 via conventional locking devices and locking hooks.

The necessary contact pressure is achieved with screws which are individually adjustable in the surrounding frame 10. Instead of the screws, spring-loaded bolts are also provided.

Towards the inside of the oven, the coke oven door has a shield construction with a metal shield 11 which is held on the coke oven door by spacers 12.

In the exemplary embodiment according to FIG. 1, the chamber frame 4 has conventional dimensions e.g. a dimension of approx. 175 mm in the longitudinal direction of the furnace. Through the web 20, its heat absorption in the hotter area of the furnace wall and the heat conduction to the chamber frame 4, the temperature in the gap between the edge 9 of the sheet 7 is increased by approximately 100 ° C. compared to conventional chamber frames. In the exemplary embodiment, this is approximately 350 ° C. compared to a maximum sealing gap temperature of approximately 250 ° C. in conventional coke ovens.

The web 20 can optionally also be arranged flush with the inner wall of the furnace, so that it forms a flange on the chamber frame 4.

FIG. 2 shows a further construction according to the invention. Instead of the chamber frame 4, a plate-shaped chamber frame 15 made of heat-resistant material, here boiler steel, possibly also made of a highly heat-resistant chrome / nickel steel, is provided. The frame 15 has a thickness of 50 mm, preferably a thickness of not more than 60 mm, so that the sealing surface between the coke oven door and the chamber frame is 125 mm closer to the first heating cable 3 compared to the solution according to FIG. This results in a distance 22 that is less than 200 mm. Due to the closer proximity to the heating flue, the sealing surface is exposed to hotter furnace zones and a sealing gap temperature of 400 ° C. is reached in the exemplary embodiment.

The exemplary embodiment according to FIG. 2 also differs from that according to FIG. 1 in a differently designed coke oven door. The essential difference is formed by a sheet metal 16 protruding outward from the surrounding frame 10. Preferably, the outside of the sheet 16 of the coke oven door is provided with insulation 17 that is 30 mm maximum and 40 mm thick. The sheet 16 and the insulation 17 enclose a gas channel 18 which has a large volume, so that incoming raw gas can flow freely upward in the direction of the gas collection space.

The door plate is docked to sheet metal 16 at 19. A sheet metal profile is used for docking, which is either composed of individual parts or is in one piece over the door length and has a multiplicity of gas inlet openings, at least one at the top and one at the bottom.

To lock the coke oven door, pivotable single-arm locks (not shown) are provided on the peripheral frame 10, which are connected to one another via rods, so that the single-arm locks located on each longitudinal spar can be pivoted together. When pivoting, the locking arms lie under the locking hooks attached to the chamber frame 15. The locking hooks are either screwed directly into the plate-shaped chamber frame 15. Or there are brackets welded to the chamber frame 15, which have suitable threaded bores for the locking hooks.

Figure 2 also shows trestles 23 which are welded to the plate-shaped chamber frame 15 and bridge the distance to the clamps 5.

There are as many blocks 23 on the chamber frame 15 as there are clamps 5. The space between the trestles is left open in order to use the small plate thickness of the chamber frame 15. The low plate thickness is an advantage because there is a small temperature difference between the top and bottom, which is decisive for bending due to thermal expansion. That with a small sheet thickness there is only a slight bend.

Instead of the blocks 23, cams or other spacers can also be provided.

According to FIG. 1, a compensation layer 24 is provided between the chamber frame 15 and the brickwork. The compensation layer 24 ensures that the chamber frame 15 and the masonry lie against one another in the sense of an optimal transfer of the heat. The compensation layer 24 expediently consists of a material which is a good heat conductor.

A new type of seal between chamber frame 15 and the furnace is shown in broken lines in FIG. The new type of seal replaces conventional caulking. In the exemplary embodiment, the novel seal, designated 25, is a sheet metal enclosing the chamber frame in an annular or tubular manner, one end of which is welded to the chamber frame 15 and the other end of which is welded to the wall protection plate 6. In the exemplary embodiment, expansion folds are provided between both ends. However, it is also possible, if appropriate, to use a sheet without expansion folds which, due to sufficient flexibility, follows the expansion movements of the chamber frame and wall protection plates. However, a tubular, non-metallic material can also be used, which is attached at both ends in the same way as the sheet 25.

The novel seal can also be used independently of the chamber frame shown here.

Claims

Patent claims

1. coke oven with heating cables lying in the masonry for heating, with door frames that are let into the coke oven brickwork, and with coke oven doors, characterized in that to increase the surface temperature in the sealing gap between the coke oven door and chamber frame to at least 300 c the distance to the first heating train is shortened by at least 130 mm or to a maximum of 200 mm and / or the chamber frame (4) projects into the masonry (2) with a web (20).

2. Coke oven according to claim 1, characterized by a plate-shaped chamber frame (15).

3. Coke oven according to claim 2, characterized in that the plate-shaped chamber frame (15) consists of boiler plate and is at most 60 mm thick.

4. Coke oven according to claim 2 or 3, characterized gekenn¬ characterized in that the plate-shaped chamber frame (15) with trestles (23) is provided.

5. Coke oven according to one or more of claims 1 to 4, characterized by a compensating layer (24) between the chamber frame and masonry (2).

6. coke oven according to one or more of claims 1 to 5, characterized by an extending from the wall protection plate 6 to the chamber frame er¬ tubular or tubular seal (25).

7. Coke oven according to claim 6, characterized by a welded sheet with expansion folds between the connection points on the wall protection plates 6 and the chamber frame (15).

8. coke oven according to one or more of claims 1 to 7, characterized by a coke oven door with in the area of the sealing gap surrounding frame (10) and a sealing unit (16) which bulges up over the surrounding frame (10) and a coke side ( 11) and forms a gas duct (18) behind the shield.

9. coke oven according to claim 8, characterized in that the shield (11) is docked.

10. Coke oven according to one or more of claims 1 to 9, characterized in that the Koksofen¬ door has a sheet metal jacket (16) which is provided with insulation (17) whose thickness ax. Is 40 mm.