EP1566427A1

EP1566427A1 - Method for reinforcing the heating walls of a coke oven battery

Info

Publication number: EP1566427A1
Application number: EP05101062A
Authority: EP
Inventors: Stefano Pivot
Original assignee: SMS Demag SpA
Current assignee: SMS Demag SpA
Priority date: 2004-02-18
Filing date: 2005-02-14
Publication date: 2005-08-24
Also published as: ITGE20040012A1

Abstract

Method for reinforcing the combustion chamber walls of batteries of chambers in coke production ovens, characterized in that the bricks (M1) of the end zones of the wall structures (S) housing the combustion chambers (C1, C2 .. Cn) have a greater thickness than the bricks of the wall structures housing the intermediate combustion chambers C. In order to compensate to this greater tickness of the walls, the chambers having walls of bricks (M1) of greater thickness are supplied with a greater quantity of combustible gas and comburent air. <IMAGE>

Description

The present invention relates to coke ovens. As is known, these ovens comprise chambers inside which combustion of the gases for heating the oven is performed, these chambers being bounded by relatively thin walls (about ten centimetres thick) consisting of refractory bricks which separate these chambers from the distillation chambers inside which the coal, usually lithanthrax, is charged for conversion into coke. These groups of combustion chambers and distillation chambers form the so-called "batteries" of coke ovens. Since, inside distillation chambers, the coal swells as it is heated, the walls of these chambers must withstand considerable horizontal thrusts which cause them to behave like plates stressed by forces which in certain moments may reach as much as 80 tonnes acting on a refractory material which cannot withstand tensile stress. These forces are sustained by the roof of the oven and the base which, in order to allow these walls to withstand these horizontal stresses, must compress them properly. For this purpose, a heavy roof is used and the distance between the two walls which form the abutment must be sufficiently wide in order to provide it with a larger base which in turn results in a greater moment of resistance, since this greater arm for this weight provides the structure with a stabilizing moment in relation to a thrust of this type.

However, in all the batteries of coke ovens it happens that, after a more or less prolonged operating period, the walls of the batteries must be protected since the bricks of said walls crumble and break. The reason for which the bricks break is twofold. A first reason lies in the flexing of the walls under the thrust of the coal which swells inside the neighbouring distillation chambers and a second reason is due to the fact that when the doors of the ovens are opened in order to remove the coke, the bricks on the top ends of the batteries are subject to a major thermal shock.

The object of the present invention is therefore to provide a method able to overcome these drawbacks of the present coke ovens.

In accordance with a main characteristic feature of the present invention, it has been surprisingly found that it is possible to avoid the drawbacks and the problems of the known art and at the same time improve the set of batteries of coke ovens, by providing the bricks in the end zones of the walls with a greater thickness. This increase in thickness of the bricks is, however, limited, as mentioned above, solely to the end parts of the said walls and does not affect the thickness of the central part of the wall, since it is through this wall that the heat must be transmitted to the coal charge inside the distillation chambers, so that the thinner these walls the better.

In order to compensate for this increase in thickness in the end zones of the walls of the brick structures housing the combustion chambers, a slightly greater quantity of combustible gas and comburent air mixture is supplied into those combustion chambers where the bricks are thicker.

Further objects and advantages of the present invention will emerge during the course of the following description of a preferred embodiment thereof, illustrated in the accompanying drawings, in which:

Figure 1 is a schematic axonometric view, with parts sectioned, of a fragment of a battery of a coke oven; and

Figure 2 is a longitudinally sectioned view of a brick wall structure housing the combustion chambers of a coke oven.

With reference to the drawings, D denotes the distillation chambers of a coke oven. For the sake of simplicity of description, in the drawing both the openings for loading the coal into the chambers D and the ducts for discharging the distillation products from said chambers have been omitted since these elements are within the public domain and illustration thereof has no bearing for the purposes of the present invention. S denotes the brick wall structures housing the combustion chambers C. In this case also illustration of the preheaters of the comburent air and the combustion gas, the fume discharge ducts and the ducts supplying the combustion gas and the comburent air to the chambers C has been omitted, since these are elements which are commonly known and not necessary for understanding the invention.

As illustrated in Figure 2, the bricks M1 of the walls of the end combustion chambers, and for example the walls of the combustion chambers C1, C2 and C3, have a thickness greater than the thickness of the bricks M of the central chambers C. Owing to this increase in thickness of the bricks of the end combustion chambers, a greater resistance both to the thermal shock following opening of the distillation chambers 1 for removal of the coke produced and to the mechanical stresses of the structure is obtained, with a consequent greater duration of the said ovens.

As stated above, this increase in thickness of the bricks is limited solely to the bricks M1 of the end parts of the said wall structures S and does not affect the thickness of the bricks M forming the central part of the said wall structure S, since it is through this wall that the heat must be transmitted to the coal charge contained in the distillation chambers D, so that the thickness of the bricks M must be contained within the smallest limits possible.

In order to compensate for this increase in thickness of the bricks in the end zones of the walls S of the batteries, which would result in a smaller supply of heat to the chambers D in these zones, a slightly greater quantity of combustion gas and comburent air is supplied into the combustion chambers C1, C2, C3 ... where the bricks are thicker, and a slightly smaller quantity is supplied to the remaining 90% of the combustion chambers C in the central wall part of the batteries.

Obviously, the present invention is not limited to the embodiments illustrated and described. Thus, for example, despite the fact that in the drawing only three combustion chambers for each end of the set S of combustion chambers have been shown as equipped with bricks of greater thickness, it is understood that the number of these chambers may be different. Moreover, it is possible to envisage that the transition from bricks of greater thickness to bricks which are relatively thin in the central zone occurs in a somewhat gradual manner.

Therefore the present invention is not limited to that described and illustrated, but comprises all those variants and modifications which fall within the scope of the inventive idea, substantially as claimed below.

Claims

Method for reinforcing the combustion chamber walls of batteries of chambers in coke production ovens, characterized in that the bricks (M1) of the end zones of the wall structures (S) housing the combustion chambers (C1, C2 .. Cn) have a greater thickness than the bricks of the wall structures housing the intermediate combustion chambers C.
Method according to Claim 1, in which the said combustion chambers (C1, C2, C3 .. Cn) having walls (M1) of greater thickness represent about 10% of the combustion chambers (C) in each battery of the oven.
Method according to the preceding claims, in which the transition between walls with bricks (M1) of greater thickness and walls with thin bricks (M) in each wall structure (S) occurs in a gradual manner.
Method according to any one of the preceding claims, in which the combustion chambers with walls of bricks (M1) of greater thickness are supplied with a greater quantity of combustible gas and comburent air.