METHOD FOR COKE OVEN REPAIR

Abstract

The ovens (F) are arranged side by side in a battery and are each delimited by two sidewalls (10) formed by side bricks (11) and joined by transverse bricks (12, 13). The method comprises: cutting each sidewall (10) to be repaired in accordance with a cutting plane (PC) defining a respective end flat face (14) in the middle portion of the wall (10a) to be maintained and coinciding with the face of a row of transverse bricks (12, 13) facing an adjacent end wall portion (10b) which is being removed; providing in each flat end face (14), a pair of cutouts (15), each having in a basic transverse face, a longitudinal middle channel (15c) in which a tongue (11c) of new bricks from a new end wall portion (10b) is fitted; fitting in each cutout (15) a corresponding portion of a vertical row of side bricks (11a, 11b) for the new end wall portion (10b) until the formation is complete.

Claims

1. Method for the repair of coke ovens arranged side by side in a battery which are each delimited by two hollow sidewalls, each formed by side bricks, superimposed in two opposed and spaced rows and spaced together by transverse bricks and defining, between them, heating chambers, wherein the method comprises the following steps: selecting a group of adjacent sidewalls and having a middle wall portion to be kept throughout the repair and two end wall portions to be replaced by new end wall portions; cutting each sidewall to be repaired in accordance with a cross-sectional vertical cutting plane in order to define a respective flat end face in the middle wall portion, said cutting plane being coincident with a face of a transverse row of bricks facing the adjacent end wall portion being removed; providing, in the region of each flat end face of the middle wall portion, a pair of side and opposing cutouts and extending over the entire height of the sidewall; producing, at a basic transverse face of each cutout, a middle longitudinal channel defining a groove for a corresponding tongue of the new bricks, the larger side and standard side of the new end wall portion; fitting, in each cutout of a flat end face, the corresponding portion of a vertical row of side bricks of an new adjacent portion of the end wall, and the said side bricks comprise, alternately along the vertical row, a new standard side brick of a length equal to the side bricks of the middle wall portion, and a new larger side brick; and completing the formation of the new end wall portion using new transverse bricks.

2. Method according to claim 1, wherein the new standard side brick has a length equal to that of the side bricks in the middle wall portion, the new larger side brick having a length equal to the sum of the length of the other side bricks in each sidewall with the axial depth of the cutouts.

3. Method according to claim 1, wherein the new transverse bricks have the same standard construction of the transverse bricks in the sidewall being restored.

4. Method according to claim 1, wherein the formation of new end wall portion is carried out by applying, at the junction regions of the new standard side bricks and larger side bricks and the new transverse bricks, between themselves and with the old side bricks, an appropriate amount of refractory mass to ensure the desired sealing at the joints.

5. Method according to claim 1, wherein the oven battery supports rails for the displacement of the loading machine and which are transversely supported on the sidewalls of the ovens along the entire length of the oven battery, wherein the method further includes, between the step of selecting the group of adjacent sidewalls to be repaired and the step of cutting each sidewall to be repaired, the step of structurally reinforcing the rails in the gaps to be formed by the sidewalls that are dismantled for repair by means of a pair of beams, each fixed along one side of each rail, these beams being dimensioned to cover the entire gap being formed by the partially or completely demolished walls, relying on at least some of the walls closest to the gap to be covered by rail.

6. Method according to claim 5, wherein each rail has its base longitudinally seated and fixed on a metal “I” profile which is reinforced by the respective pair of beams; and the webs of the two beams and the metal “I” metal profile being crossed by a clamping stud.

7. Method according to claim 5, wherein each beam comprises two “I” shaped metal profiles welded side by side by the longitudinal edges of their upper and lower flanges, and the outer lower flanges of the two pairs of “I” shaped profiles are fixed on the ends of a plurality of metal and transversely disposed base plates spaced apart along the length of the beams and on the middle portion of which the metal profile “I” is seated on which the respective rail is supported.

8. Method according to claim 7, wherein each two adjacent rails are further structurally interconnected by means of metallic sleepers with their ends fixed on the outer lower flanges in the bordering beams.

9. Method according to claim 1, further including, after the step of cutting each sidewall to be repaired, and the removal of the end wall portion to be replaced, the provision of: a plurality of metal and detachable struts, each having a flat end face of the middle wall portion supported by front or rear structures of the oven battery; and metal and detachable top struts, arranged between confronting top regions of opposite oven walls of a gap defined by the partial or complete removal of walls to be repaired.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will now be described with reference to the accompanying drawings, given by way of example, in which:

[0025] FIG. 1 is a simplified and somewhat schematic top plan view of a coke oven battery comprising a plurality of ovens arranged side by side between two thermal insulation end walls of the battery;

[0026] FIG. 2 is a partial cross-sectional view of the coke oven battery, the cut being taken along line II-II in FIG. 1;

[0027] FIG. 3 is a similar view to that in FIG. 1, but only partially illustrating the oven battery with one of the thermal insulation end walls seated against a containment wall with three sidewalls defined only by their middle portions and having their opposite end portions already removed to be replaced by new end portions, and with two sidewalls totally removed for complete replacement by new walls;

[0028] FIG. 4 is an enlarged and partially cut-away plan view of the middle portion of one of the sidewalls, illustrating not only the middle portion, but also, in dashed lines, part of the end portions to be removed, as well as the indication of the cutting plane for these walls;

[0029] FIG. 5 is a similar view to that in FIG. 4 but showing only one of the cut ends of the middle wall portion;

[0030] FIG. 6 is a similar view to that shown in FIG. 5, but illustrating a pair of opposite side cutouts, provided at one of the cut ends of the middle wall portion and extended over the full height of the respective middle wall portion;

[0031] FIG. 7 is a similar view to that presented in FIG. 6, but showing a middle channel extended over the entire height of the basic transverse face of each cutout of the pair of the opposite side cutouts, in order to define a respective groove;

[0032] FIG. 8 is a similar view to that presented in FIG. 7, but illustrating the assembly of a new larger side brick and a new standard side brick, in their respective cutouts of the new end wall portion;

[0033] FIG. 9 is a plan view of a small extension of the reinforcing structure to support one of the rails of the loading machine; and

[0034] FIG. 10 represents a cross-sectional view of the frame portion shown in FIG. 8.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0035] As described above and illustrated in the drawing figures, the method is applied to ovens F for the production of coke that are arranged side by side in batteries and each comprising two sidewalls 10, opposite one another, and one of them is common to two adjacent ovens F. The sidewalls 10 are formed by side bricks 11 and transverse bricks 12 and 13, the latter being arranged in vertical columns, spaced apart from each other to define, within each sidewall 10, a plurality of heating chambers CA (or combustion chambers) arranged vertically and providing a hollow construction to each of said lateral sidewalls 10. The side bricks 11 and transverse bricks 12 and 13 are made of refractory material such as silica, fireclay, clinker or insulating material.

[0036] The opposing sidewalls 11 are seated on a generally concrete base (not shown), and are closed at the top by a top wall PT, in refractory bricks. Each oven F is closed at the top by a roof T, also made of refractory material and provided with loading ports (not shown) to allow charging of mineral coal to be processed into coke (see FIGS. 1, 2 and 3) in a constructive arrangement that is well known in the art.

[0037] Each heating chamber CA is internally and inferiorly provided with a ceramic burner Q that is sized to allow the combustion within each chamber to produce, within the two adjacent ovens F, the degree of heating required for the transformation of the mineral coal into coke.

[0038] As shown in FIG. 2, the oven battery is usually mounted on a respective set of thermal regenerators RT of known construction, to allow thermal reuse of the combustion gases expelled from the heating chambers CA.

[0039] As illustrated in FIGS. 1 and 3, the end sidewalls 10 of each oven battery F are laterally seated against insulating end walls 20, each of which being externally and laterally propped against a retaining wall 30 shown only in FIG. 3.

[0040] Also, as illustrated in FIGS. 1 and 3, the sidewalls 10 have their ends anchored by suitable front and rear structures E, which may be of any suitable construction and already incorporated in the prior art, thus not being part of the inventive aspects of this present method.

[0041] As already mentioned in the introduction to this application, partial and even total periodic replacement of the sidewalls 10 in ovens F of a battery is required.

[0042] FIG. 3 illustrates, in a simplified manner, the leftmost region of the battery of FIG. 1, with the first three sidewalls 10 represented only by their middle wall portions 10a due to the fact that their end wall portions 10b (see FIGS. 3 and 4) have been removed according to their degree of wear. Also shown in FIG. 3 is the complete removal of two sidewalls 10 adjacent to said middle portions 10a of the partially removed sidewalls 10.

[0043] FIG. 4 is an enlarged and partially cut away plan of a sidewall 10, showing in solid lines, the middle wall portion 10a, and in dashed lines showing the end wall portions 10b that will have their side bricks 11 and transverse bricks 12 and 13 replaced by new bricks.

[0044] Thus, the method in question begins with the step of selecting a group of adjacent sidewalls 10 that have a middle wall portion 10a to be maintained in the oven battery F and two end wall portions 10b to be replaced by new end wall portions.

[0045] According to the proposed method, the replacement of the end wall portions 10b is obtained through a step of cutting each sidewall 10 to be repaired, in a cross-sectional vertical cutting plane PC, in order to define a respective flat end face 14 in the middle wall portion 10a, each cutting plane PC coinciding with a face of a transverse row of bricks 12, 13, facing the adjacent end wall portion 10b that is being removed.

[0046] With this cutting operation, each cutting plane PC intersects the tongue of the transverse bricks 13 which project to one of the outer faces of the sidewall 10, and also the side bricks 11 adjacent to the opposite outer face of the sidewall 10. These flat vertical cutting operations define, on each opposite end of the remaining middle wall portion 10a, a flat end face 14 shown in FIGS. 4 and 5 and devoid of surface accidents to provide mechanical locking between the new bricks in the end wall portion 10b and the old bricks in the middle wall portion 10a.

[0047] Due to the already mentioned difficulty to provide the adequate junction of said flat end faces 14 in the middle wall portion 10a with the new end wall portions 10b, by using complex and expensive ceramic welds, the method in question also comprises a step of providing in the region of each flat end face 14 in the middle wall portion 10a, a pair of cutouts 15 in opposite sides that cover the entire height of the sidewall 10. Each cut has generally straight dihedral walls with a basic transverse wall and a longitudinal wall that define the longitudinal depth of each cutout 15.

[0048] In order to guarantee solid locking between each new end wall portion 10b and the middle wall portion 10a, in each basic transverse face of each cutout 15, a middle longitudinal channel 15c is produced, which defines a groove for a corresponding tongue 11c of new bricks, larger side 11b and standard side 11a of the new end wall portion 10b.

[0049] The cutting operation can be performed, for example, with a manual cutting machine, in a sufficiently precise manner, but which provides a flat end wall 14 devoid of any tongue and groove.

[0050] Upon execution of the cutouts 15 in the flat end faces 14 of each middle wall portion 10a, a new step can be initiated, comprising the fitting of a portion corresponding to a vertical row of side bricks 11 in a new adjacent end wall portion 10b. These side bricks comprise, alternately along the vertical row, a new standard side brick of equal length to that of the side bricks 11 of the middle wall portion 10a, and a new larger side brick 11b, having a length equal to the sum of the length X of the other side bricks 11 of each sidewall 10 with the longitudinal depth y of the cutouts 15, as shown in FIG. 6.

[0051] The provision of the new larger side brick 11b results from the fact that each cutout 15 is transversely aligned with another cutout 15 in the same flat end wall 14, thus requiring one of the new side bricks, herein called ‘larger brick’ 11b, to present a greater length than the standard length of bricks 11 in the middle wall portion 10a, which is the same as other standard bricks 11a in the new end wall portion 10b, so that the same arrangement of bricks in “rows” can be maintained. The new transverse bricks 12a and 13a have the same standard construction as the transverse bricks 12 and 13 in the sidewall 10 that is being restored.

[0052] The fitting of the tongue 11c of the new bricks, larger side 11b and standard side 11a, into the middle longitudinal channel 15c of the basic transverse face in each cutout 15 allows the fit between the old bricks and new bricks to withstand the transversal expanding forces of the coal under treatment.

[0053] The junction regions of the new side bricks 11a and 11b and of the new transverse bricks 12a and 13a, with each other and with the old side bricks 11, only receive the appropriate amount of refractory mass to ensure the desired sealing of the joints, making it unnecessary to execute any ceramic welding.

[0054] This assembly provides a robust transverse mechanical locking between the middle wall portion 10a and the new end wall portions 10b, preventing relative displacement between said middle wall portions 10a and end walls 10b, in an direction orthogonal to their common assembly plane during normal operation of ovens F.

[0055] Typically, the sidewalls 10 are disposed on a lower portion of the ovens F constructed in known manner to define the aforementioned thermal regenerators RT. The method in question allows the walls of these thermal regenerators RT to also be restored concurrently with the repairs of the sidewalls 10 of ovens F, with the same benefits already mentioned regarding robustness with mechanical locking and sealing without formation of cracks and ensuring greater operational life between repairs.

[0056] Another innovative aspect of the solution proposed herein allows the significant increase on the number of sidewalls 10 to be simultaneously partially or completely restored. According to the oven battery F construction type considered here, the loading machine (not shown) travels over the battery, supported on rails 40 which are transversally supported on the sidewalls 10 of the ovens F throughout the extension of the oven battery (see FIG. 3).

[0057] Due to the weight of the loading machine, particularly when loaded, the span of the rails 40 devoid of the support from the sidewalls 10 should normally not exceed four sidewalls 10, i.e. it does not allow the simultaneous restoration of more than three or four ovens F, which increases the cost of repair, requiring a greater number of operating interruptions for successive repairs of smaller scale.

[0058] To reduce the costs of such partial and/or complete repair operations of the ovens F, the present invention also proposes the step of structurally reinforcing the rails 40 in the spans to be formed by the sidewalls 10 that were demolished for repair, as shown in FIGS. 3, 8 and 9.

[0059] Each rail 40 has its base longitudinally seated and fixed on a metal profile “I” 50 which is reinforced by a pair of beams 60, in the form of double “I” shaped metal profiles and welded side by side on the longitudinal ends of their top and lower flanges. The webs of the “I” profiles in the two beams 60 are crossed by a gripping stud 65 and the outer lower flanges of the two pairs of “I” profiles are fixed on the ends of a plurality of transversely arranged metallic base plates 70, spaced apart along the length of the beams 60, on whose middle portion the steel profile “I” 50 is seated and upon which rail 40 is supported.

[0060] The beams 60 are sized to fully cover the span to be formed by the partially or completely demolished walls, bearing on at least some of the walls near the span that will be covered by the rail.

[0061] In addition to the two beams 60 on each rail being fixed on the base plates 70, and thus also being lower and structurally interconnected, each two adjacent rails 40 are further structurally interconnected by means of metal sleepers 80 with their ends fixed on the external lower flanges of bordering beams 60, as partially illustrated in FIG. 8.

[0062] With the above arrangement, the load on the rails 40 is transferred to the gripping studs 65 and to the beams 60 in the region of the spans formed by the removal of walls or end wall portions, so that the beam ends 60 are supported on the remaining walls of the oven battery F, closer to the region of formation of the span. With this procedure, it becomes possible to safely cover spans of about 10 meters, i.e. spans resulting from the removal of about seven sidewalls 10, without prejudice to the continued operation of the loading machine on the battery of ovens F, regardless of whether the walls of each span being repaired have been partially or completely removed.

[0063] As schematically illustrated in FIG. 3, upon the removal of the end wall portions 10b, the flat end faces 14 of the middle wall portion 10a are held against the respective structures E on struts 90 made of metallic material and easily detachable. Similarly, the sidewalls 10 or sidewall portions 10a that define, due to the removal of the walls for repair, a gap corresponding to two or more walls, have their top region supported against confronting end regions of an opposite wall, by top struts 95 that are also metallic and detachable and may be in the form of profiles or frames.

[0064] The method in question presents the following advantageous aspects compared to those that have been used according to the state of the art: [0065] a) The limitations of the previous method which does not allow the repair to be executed in mixed phases (partial and full repairs in the same batch) causes the need to perform the repair on a larger number of steps, significantly increasing the total repair time, resulting in greater loss of production and higher consumption of coke gas in order to keep the remaining areas on stand-by. The method in question uses a special insulation and shoring system that allows the correct and safe execution of a mixed batch (walls with partial and complete repair—FIG. 3) [0066] b) The method in question allows to repair more adjacent walls (up to about 8 to 10), with reduced repair time and overall savings mentioned above. [0067] c) The new method provides, for each type of repair, a solution to support the rails of the loading machine. Thus, it ensures the safe transit of the machine over the repair area, eliminating any effort that would inevitably be transmitted to the remaining stand-by areas of the lot to be repaired. [0068] d) The bracing of the sidewalls of the battery adjacent to the lot being repaired guarantees perfect geometry and sealing of the other sidewalls of the battery which are kept in operation. [0069] e) The recovery of the mechanical parts after the demolition of the refractory, bringing them back to their original topography. A spring system allows the control of the expansion of the new refractory, total or complete, during heating. [0070] f) In case of partial repair, the new method considers the design and supply of the wall portion to be replaced. No adjustment of refractory parts is required in the field and all the “rows” of bricks are fitted as provided for in the design. The connecting part between the new part and the remainder is made with a specially shaped brick designed appropriately in the engineering phase. The cut in the old wall is complemented by the milling of a “groove” in the front of the remaining wall. In the set mentioned above (sliding joint) an aluminum foil is interposed, which facilitates the sliding of the new part in relation to the old part, when heating. [0071] g) The new method does not require adjustments or interventions in the refractory wall after heating and the mechanical part is carried out in full compliance with the topographic adjustment made after the demolition of the refractory. [0072] h) The new method uses bricks of special dimension to obtain the sliding joint, not requiring the application of any type of ceramic welding. The perfect sealing pressure and improved mechanical strength ensure that all the requirements of the repair are met. [0073] i) The new method also provides for and allows the execution of repairs in the corresponding thermal regenerators RT, simultaneously with the repair of the heating sidewalls 10, with significant gains in terms of reduction in total execution time of the repair.

[0074] Besides the above mentioned advantages, it should be noted that the new method is effective with regard to the ease of repair execution, to the elimination of the need for adjustments in the field and to the provision of a perfect pressure seal, with high mechanical strength without requiring periodic maintenance and ceramic welding in the connection between the new bricks and old bricks (sliding joint).

[0075] The improvements resulting from the new method described above enable an overall reduction of repair costs due to the substantial reduction in execution time and consequent optimization of labor, among other factors mentioned, such as not needing the application of ceramic welding.