US3809620A - Horizontal coke oven - Google Patents

Abstract

A high capacity coke oven including a battery of horizontally spaced coke oven chambers each having heating walls. Vertical heating flues are formed by a plurality of bondstone walls between the heating walls for adjacent coke chambers. The bondstone walls are constructed form bricks having a thickness between 60 to 80 millimeters. The heating walls are constructed form stretcher bricks having a thickness between 70 to 90 millimeters in the heat transfer direction extending form the heating to the coke oven chamber.

Description

May 7, 1974 F. WACKERBARTH ET AL 0 HORIZONTAL COKE OVEN Filed July 25, 1972 2 Sheets-Sheet 1 l2 8 l7 l2 1/ y 1974 F. WACKERBARTH ETAL 3,809,620

HORIZONTAL COKE OVEN 2 Sheets-Sheet 2 Filed July 25, 1972 FIG. 3.

FIG. 4.

United States Patent 3,809,620 HORIZONTAL COKE OVEN Folkard Wackerbarth, Bochum, and Knrt-Giinther Beck,

Essen, Germany, assignors to Dr. C. Otto & Comp.,

GmbH, Bochnm, Germany Filed July 25, 1972, Ser. No. 274,480 Claims priority, application Germany, Dec. 14, 1971, P 21 61 980.7 Int. Cl. C10b 1/06, 5/02 US. Cl. 202-139 4 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION In a coke oven, a plurality of heating fiues are formed between the walls separating the oven chambers to provide the necessary heat for the coking process. The heating flues extend in a vertical direction and at their bases burners are fired with either very high caloric value gas which does not require preheating or a lower caloric value gas may be used when it is preheated by a regenerative heat exchange. The Otto type high capacity coke oven has a twin-flue heating system. Gas and air are burned in the upfiowing flue and the waste gas passes the turning point and flows downward through the adjacent flues to the regenerators. The heating walls consist of a number of these twin-fines, arranged side-by-side. Combustion takes places in every second flue during regeneration heating periods so as to provide a uniform heating over the entire wall. Bondstone walls are used to form the flue between the heating Walls.

It is believed apparent that thinner stretcher bricks for the heating walls will produce a better heat transfer between the burning of gases in the heating fines and the coal charge in the oven chamber. Attempts toward reducing the stretcher brick thickness have met with continued objections since the brick structure of the heating fines is subject to many different stresses. In this regard, the loadability of the heating wall was of major importance in view of the weight of the oven crown and the movement of the coal charging car upon the top of the oven crown. It was assumed in the past, that the heating walls can be unloaded to a large extent when bondstone walls as basic support structures were made solid to the oven crown between pairs of heating flues. The thickness of known bondstone walls is within the range of 130-150 millimeters in order to provide suificient strength. This made it possible to form the heating walls from stretcher bricks having a thickness within the range of 65-100 millimeters to thereby increase the heat flow into the oven chamber.

There are only isolated instances where coke oven heating walls have been built from stretcher bricks having a thickness below 100 millimeters. For example, a German gas plant has a regenerative coke oven of the Otto underburner type with an average heating chamber Width of 336 millimeters. The stretcher brick making up the heating walls are 80 millimeters in the thickness for almost the entire height of the walls. In this coke oven, the bondstone walls employ both continuous and non- 3,809,620 Patented May 7, 1974 continuous bricks which have a thickness of 130 millimeters.

A battery of horizontal coke ovens were built in the Ruhr area 40 years ago which have heating walls formed from stretcher bricks that are millimeters thick and define an average width oven chamber of 450 millimeters. This coke oven was of the Otto underburner regen erative type and when operated on a continuous basis, the coking time was less than 12 hours. The bondstone walls in the flue remained at a thickness of approximately 150 millimeters. Thus, in the majority of the cases, the thickness of the stretcher bricks for the heating walls did not fall below millimeters and with respect to the brick thickness for the bondstone walls, e.g., 130 millimeters or more was the common practice.

Recent studies have provided other concepts and requirements dealing with the construction of coke oven heating walls. These studies were directed to the compressive bending and shear stresses in the oven heating Walls. Taken into consideration, was both the weight of the heating walls and the oven crown, as well as the forces attributed to bracing by tie elements and supports. The weight and the expansion properties of the coal charge in the coke oven chamber are other factors taken into consideration. On the basis of the foregoing, the present invention is directed to shortening the coking time by reducing the thickness of the heating walls in a coke oven.

SUMMARY OF THE INVENTION It has been discovered that the coking time decreases only to a limited extent in a linear relationship with the reduction in the heating wall thickness, since the flow of heat through the heating wall is much less at the zone where the bondstone walls meet the heating wall than in a zone between the bondstone walls. This invention is based on the discovery that the forces exerted upon the heating wall masonry are such that a substantial reduction in the bondstone wall thickness is possible. Thus, the coking time is reduced since a reduction in heating wall thickness can also be realized whereby the heating flue cross-sectional area is greatly increased without altering the center distance between the heating flues. This enables increased heat flow over a larger area within the heating flue area.

It is an object of the present invention to provide an improved coke oven design for greatly reducing the coking time with a constant heating flue temperature.

It is another object of the present invention to provide an improved coke oven wherein adjacent heating walls define a plurality of heating flues which are formed from bondstone walls having a thickness of less than 100 millimeters while the heating walls have a thickness of less than millimeters. In the preferred form, the present invention provides that the bondstone walls have a thickness selected between 70 to 90 millimeters and the heating walls have a thickness between 60 to 80 millimeters.

These features and advantages of the present invention as well as others will be better understood when the following description is read in light of the accompanying drawings, in which:

FIG. 1 is a perspective view of the heating fines between adjacent heating walls of a coke oven and illustrating one embodiment of the present invention;

FIG. 2 is a view taken horizontally through adjacent heating walls of a coke oven and illustrating a second embodiment of the present invention;

FIG. 3 is a view similar to FIG. 2 but illustrating a Before describing the construction details of the various embodiments of the present invention, the following general comments should be borne in mind. In each embodiment, the heating walls formed by the stretcher bricks have a thickness of between 60-70 millimeters. The bondstone walls are designed to have a thickness of between 80-90 millimeters. The inside dimensions of the heating flues are such that in the transverse direction, the dimension is somewhat below 500 millimeters and in the longitudinal direction of the heating walls, the dimension may slightly exceed 300 millimeters. The bondstone Walls, defining the heating flues, are formed from courses of two mating bricks. One of these two mating bricks used in each bondstone wall has a length which differs from wall-to-wall, thereby providing the necessary tapering of the oven chamber wherein the width of the chamber increases in the direction from the pusher side toward the coking side.

It has been found that thickness reductions of the bricks employed to construct the heating walls approaches a limit defined by the production methods of the bricks and the heating wall dimensions. These dimensions include the center distance between heating flues and the center distance between oven chambers. The bricks which are employed to construct the coke oven heating walls today consist of raw materials which are processed in a granular state and incorporate small quantities of a binder which is not in a paste-like state. These bricks are formed at very high pressures, about 500 kg./cm. in hydraulic or similar presses. Since these bricks are relatively long and narrow, they are very sensitive to the handling necessary for drying and burning of the bricks. The extent to which the thickness of the brick can be reduced is therefore related to the length of the brick.

It has been found that solely on the basis of strength, the stretcher bricks forming the heating walls can be reduced in thickness to approximately 50 millimeters and the brick for the bondstone walls can be reduced in thickness to approximately 70 millimeters.

With reference now to FIG. 1, there is illustrated heating walls 8 for one coke oven chamber and a heating wall 9 forming part of an adjacent oven chamber in a battery of coke ovens. The space between the walls 8 and 9 is divided into a plurality of heating flues 10 for the introduction of heat to the wall for the coking process. Each of the heating walls 8 and 9 are formed by courses of bricks consisting of a stretcher brick 11 positioned in an end-to-end abutting relation with a stretcher brick 12. The bricks 11 and 12 are shaped as mirror images of one another. Bondstone walls 13 extend between the heating walls 8 and 9 to define the heating flues 10. The bondstone wall is formed by courses of bricks 14 and 15. Brick 14 abuts the inside surface of one heating wall at the joint formed by the stretcher bricks 11 and 12. At the other heating wall, brick 15 forms an integral part of the heating wall and is held in position by a vertically extending slot and feather interlock joint 16 with the stretcher bricks 11 and 12. The position of bricks 14 and 15 alternate from bondstone wall to bondstone wall and from course-to-course of bricks. The horizontal contact faces between courses of bricks have interlocking slotfeather connections. One part of this conneciton is shown at 17 and 18.

The embodimentof the present invention illustrated in FIG. 2 is characterized by an increased thickness of the bondstone wall in the area between the heating walls. Alternatively, it can be stated that the thickness of each bondstone wall decreases in the direction toward the heating walls. Stretcher bricks 20 and 21 for the heating wall are constructed and arranged in the same manner as previously described with respect to the stretcher bricks 11 and 12 including the mirror image relationship. One end of each stretcher bricks 20 and 21 is positioned in an abutting relationship at 22 while their opposite ends ar j ned y te lock g s ot. and e ther connection with bricks 23 of the bondstone wall. Each brick 23 has sloping faces 24 that extend in a direction to provide an increased brick thickness between the heating walls. The courses of brick in each bondstone wall include a short brick 26 arranged in the wall to about the inside surface of the heating wall. Brick 26 has sloping faces 27 arranged in the same manner as the sloping faces 24. Bricks 23 and 26 are joined together by an interlocking slot and feather connection shown at 28. Reference numerals 29 and 30 indicate the interlocking slot and feather connections for joining surfaces between each course of the bricks forming the heating and bondstone walls. The embodiment illustrated in FIG. 2 has the advantage of providing a better heat flow between the flame burning in the flues and the coke oven chamber by the constricted flue area formed by the bricks in the bondstone wall that increases in a direction toward the heating walls.

The embodiment illustrated in FIG. 3 difiers in its essential aspect over the embodiments previously described by forming the heating walls from two identically constructed stretcher bricks 30 which are joined in an endto-end relationship at their one end while the remaining ends are tapered. The tapered ends of the stretcher bricks 30 are constructed and arranged to receive therebetween the tapered ends 31 of bricks 32 forming part of the bondstone wall. A shorter bondstone wall brick 33 supplements the brick 32 to complete the span between the heating walls. The bricks 33 rest against the joint 34 between the stretcher bricks 30. Interlocking slot and feather joints are indicated at 37 and 38 for the junction between the courses of bricks in the heating and bondstone walls.

In the embodiment of the present invention illustrated in FIG. 4, the bondstone wall 40 is formed from bricks 41 and 42 having side projections 43 and 44, respectively, formed on one of their ends. The other ends of the bricks 41 and 42 are joined together by an interlocking slot and feather connection 45. Heating wall stretcher bricks 46 have a tapered end 47 to complement a similarlytapered surface formed on the side projections 43 and 44 of bricks 41 and 42, respectively. Interlocking slot and feather connections 48 and 49 are provided to join the mating surfaces between the courses of bricks forming the heating and bondstone walls.

It will be appreciated by those skilled in the art that the bondstone walls between the heating walls in each of the above-described embodiments are formed by pro-- viding one of the two bricks shown with a different length while the other of the bricks will have the same length in each wall. In this manner, the oven chamber between heating walls is increased in width to a maximum at the coke delivery side of the oven. It has been found that by reducing the stretcher brick thickness in the heating walls, the improved heat transfer has enabled a substantial reduction in the coking time without increasing the heating flue temperature.

Although the invention has been shown in connection with certain specific embodiments, it Will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

We claim as our invention:

1. In a coke oven formed by a battery of horizontally spaced oven chambers defined by spaced-apart vertically extending heating walls, the heating walls of adjacent oven chambers being divided into a plurality of vertically extending heating flues, said heating walls being formed by courses of stretcher bricks, said stretcher bricks having a thickness of millimeters or less in the direction of heat transfer extending from said heating flues toward said oven chamber; the improvement comprising a plurality of bondstone walls defining said heating flues between said adjacent heating walls and said bondstone walls formed by courses of brick having a thickness of 100 millimeters or less.

2. A coke oven according to claim 1 wherein said bondstone walls have a thickness within the range of 70 to 90 millimeters; and said stretcher bricks having a thickness in said direction of heat transfer within the range of 60 to 80 millimeters.

3., A coke oven according to claim 2 wherein said bricks for said bondstone walls have a non-uniform thicknessf'throughout their span between said heating walls.

4. A coke oven according to claim 3 wherein the thickness of said bondstone walls decreases in a direction toward each of said heating walls.

References Cited UNITED STATES PATENTS 3,102,846 9/1963 Tucker 202139 2,141,035 12/ 1938 Daniels 202223 5 2,393,658 1/1946 Rueckel 202267 3,359,184 12/1967 Thiersch et a1. 202--267 NORMAN YUDKOFF, Primary Examiner 10 D. EDWARDS, Assistant Examiner US. Cl. X.R. 202267

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