US3266088A - Method and apparatus for producing coke - Google Patents

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Aug. 16, 1966 sc c ET AL 3,266,088

METHOD AND APPARATUS FOR PRODUCING COKE Original Filed July 5, 1962 2 Sheets-Sheet 1 I N VEN TORS' HER/MANN SC HE N CK WERNER WE NZE L Pic! BY A A TTORNEYS.

Aug. 16, 1966 sc c ET AL 3,266,088

METHOD AND APPARATUS FOR PRODUCING COKE Original Filed July 5, 1962 2 Sheets-Sheet 2 FIG.2

ATTORNEYS.

United States Patent 3,266,088 METHOD AND APPARATUS FOR PRODUCING COKE Hermann Schenek, Intzestrasse 1, and Werner Wenzel, Prinz Heinrich Strasse 29, both of Aachen, Germany Original application July 5, 1962, Ser. No. 207,751. Divided and this application Feb. 21, 1964, Ser. No. 352,709 Claims priority, application Germany, July 20, 1961, Sch 30,016; Dec. 5, 1961, Sch 30,667 1 Claim. (Cl. 18-9) This application is a division of our copending application Serial No. 207,751, filed July 5, 1962, for Method and Apparatus for Producing Coke.

This invention generally relates to coke production and is particularly directed to an improved arrangement for producing coke from fine-grained bituminous materials on stationary or movable coking grates or grinds (hereinafter referred to as grates). Considered from one aspect, the invention provides for a novel means for shaping bituminous material into self-supporting structures suitable to be coked on grates.

Considered from another aspect, the invention is concerned with a novel coke producing process wherein finegrained bituminous materials are coked on grates in a much shorter period than is possible with prior art procedures and wherein the coking procedure results in the formation of high-quality coke and in fuel-rich gases having considerable calorific content and thus great heating power (rich gas). The invention is applicable to coke production both on stationary and movable grates.

For the purpose of this application, including the appended claim, the term bituminous materials is deemed to include any bituminous substance suitable for coke manufacture, such as various kinds of coal, oil shale, mixtures of petroleum and mineral substances, wood and wood waste.

The term coke, in turn, includes, for the purpose of this application, coke proper and also metalliferous and metallurgical coke.

As is well known to those skilled in coke production, successful operation of prior art methods for coking bituminous material on stationary or moving grates requires as a prerequisite that the bituminous material has a grain size which permits a considerable gas permeability through the entire layer of bituminous material to be coked. This, in turn, means that the bitumen content of the material is not allowed to exceed a certain limit value as otherwise the gas permeability is insuflicient.

Thus, for example, it is well known in the industry that fine-grained bituminous coal having a grain size of up to mm. with the predominant portion of the coal consisting of grains or particles below 5 mm. cannot successful y be coked on grates at an economic speed. Experience has demonstrated that bituminous coal having a volatile content of above 16% is particularly unsuitable as raw material for the prior art grate coking methods. This is so because during the coking, swelling and agglomeration phenomena take place due to the heating so that the original gas permeability of the material is considerably reduced if not eliminated.

Accordingly, it is an object of this invention to provide apparatus for coking bituminous material which permits the employment of finer-grained bituminous materials having a bitumen content in excess of 16%, as for example, customary coking coals.

In the present grate coking methods, the coking of the bituminous material layer on the grates progresses in zones from the top towards the bottom. By contrast, and in accordance with a further feature of this invention, the coking of the bituminous layer is initiated and conducted ice to completion substantially simultaneously throughout the entire layer thickness of the bituminous material. This manner of operation results in a significant shortening of the coking time.

In the known grate coking procedures wherein bituminous material is coked or carbonized at relatively low temperature, the bituminous material is placed on the grate in a layer thickness of about 3 to 50 cm. The grate with the layer thereon is then moved below an igniting arch structure or crown of the furnace and the layer is thereby ignited at its top surface. It should be emphasized in this connection that the igniting exclusively takes place within a very thin surface region of the layer. Preferably preheated air is simultaneously blown through the bituminous layer either from below upwardly, or in the reverse, from the top downwardly. The coke gases which, due to this procedure, are liberated from the bituminous material burn with the air within the layer structure. Due to the heat generated in this manner, the coking of the layer gradually progresses from the top downwardly, or in the reverse, through the entire layer formation. It has been established that this prior art procedure can only be carried out in an economical and practical manner if the combustion air is blown through the bituminous layer to be coked from below upwardly and provided the bituminous layer consists of relatively large pieces of, for example, 5 to 30 mm. grain size and has non-agglomerating characteristics. Thus, for example, coal in piece form has previously been coked in this manner.

While this prior art coking method is extremely simple, it will be realized that it has the great disadvantage to the effect that it requires large piece bituminous particles. In other Words, the individual pieces of coal or the like constituting the bituminous layer have to be sufficiently large so as to ensure sufficient gas permeability through the layer. Further, the bituminous raw material, during the heating, is not allowed to melt, fuse or swell, as otherwise the gas passages within the bituminous layer become clogged. This, in turn, means that the bitumen content of the coal or the like bituminous material has to be relatively low. For the reasons hereinabove advanced, coking of ordinary coking coals, gas flame coals and gas coals was hitherto not possible in a grate coking apparatus.

By contrast, the present invention enables grate coking of extremely fine-grained, bitumen rich coals, as for example, coking coals.

In accordance with this invention, it has been ascertained that grate coking of bituminous materials of the kind indicated can successfully be carried out if the bituminous layer on the grate is imparted with channels or passages which traverse the layer and through which combustion air and the combustion products of the air with the coking gases, respectively, flow during the coking.

In a preferred embodiment, the passages referred to extend vertically through the layer.

According to a further feature of this invention, compacted coke of any desired shape is readily produced by compressing or compacting the bituminous material prior to the coking proper. The compression results in an increased density of the bituminous layer and facilitates at the same time the formation of coke of desired shape. The compression may, for example, be performed by vertically compressing the bituminous layer to be coked or by vibrating the layer, as is known in the art.

In accordance with a preferred embodiment of this aspect of the invention, the compression is effected simultaneously with the formation of the channels or passages referred to. This accomplished by passing fine-grained bituminous material such as coal between the nip of a profiled roller pair. The profiles of the roller pair are adapted so that parallel channels or passages are impressed into the bituminous compacted layer formed between the rollers in the direction of movement of the layer. The profiles may be arranged on either the upper or the lower roller, or both rollers may be provided with such profiles.

In the event that both rollers have channel-forming profiles, it is advantageous to arrange opposing profiles in somewhat offset manner and so that the profile ends or heads project or overlap, i.e. each profile extends beyond the center line of the nip. The flanks of adjacent opposite profiles adapted to form a single passage preferably contact each other or are in closely juxtaposed position during operation. For this purpose, wedge-shaped profiles may be used which are easily removed from the compressed bituminous layer without resulting in unfavorable constrictions in the passages or channels.

The aspect of the invention concerning the formation of flue passages within the bituminous layer will now be explained in detail in conjunction with the accompanying drawings forming part of this application, wherein:

FIG. 1 is a somewhat diagrammatical representation of the formation of a coal layer to be coked on a grate; and

FIG. 2 is a diagrammatical representation of a grate coking device incorporating the profile rollers illustrated in FIG. 1.

FIG. 1 diagrammatically illustrates the production of a bituminous coal layer 3 having parallely extending passages to be traversed by gas. The bituminous layer is formed by feeding fine-grained bituminous coal particles between a roller pair consisting of an upper roller 5 and a lower roller 7. Both rollers 5, 7 are provided with parallel extending profile members 6 of identical shape. It will be noted that the profile members 6 have wedge-shaped end portions 10 which are arranged in opposing relationship so that one side of the upper wedge 10 contacts the opposing side of the lower wedge 10. In this manner a continuous bearing surface 8 between these wedge portions or sides is created. When the coal particles are fed between the roller pair, the roller pair not only compresses the particles into a comparted layer 3, but at the same time, the profiles 6 penetrate the layer and form continuous channels therein. These channels or passages extend in vertical manner. It will be noted that due to the offset arrangement of the ends of opposing profile members 6 with the contacting side or flank portions, channels of substantially uniform cross-section are obtained.

The roller pair is advantageously arranged at the charging end of the grate so that the bituminous particles are compacted and imparted with channels while being fed to the grate. If the grate is moving, the speed of the grate may be synchronized with that of the rollers.

FIG. 2 diagrammatically indicates a coking apparatus incorporating the profile rollers of FIG. 1. The coker comprises a combustion chamber 60 defined by the arch structure 58. The combustion chamber merges upwardly with a flue gas exit 56 which leads, for example, through a boiler or the like. Below the combustion chamber 60, there is mounted a movable grate generally indicated by reference numeral 56. Grate 56 is trained around rollers 54 and supports the coal layer 52. Coal 50 is introduced through hopper 49, which comprises feeding means for the profile rollers. Thus, at the discharge of the hopper, the coal pieces are compressed and shaped by profile rollers 48 and 46 which are of the construction indicated in FIG. 1.

The compressed coal, in layer form as indicated at 52, is then coked within the coker and the finished coke is discharged from grate 56 at the exit side thereof as indicated at 45. Primary combustion air is introduced through the grate structure and thus through coal layer 52 by means of a manifold 41 connecting a plurality of vertically rising gas pipes 40. Manifold 41, in turn, is supplied with air entering through pipe 39 and discharged by blower 38. Secondary air flows in the direction of the arrows C through flue passages traversing arch structure 58, and indicated at 36. The secondary air causes partial combustion of the coked gases rising through and from layer 52.

What is claimed is:

A device for forming self-supporting compressed shapes of fine-grained bituminous material, which comprises a pair of rollers forming a nip; and means for feeding finegrained bituminous material into the nip of said roller pair; each roller having a plurality of axially spaced, circumferentially extending parallel projecting means, the projecting means of opposing rollers being substantially in alignment, each of said projecting means having a substantially right triangle cross-section tapering radially outwardly, with a hypotenuse surface complementary to a hypotenuse surface on the corresponding opposing projecting means, the opposing complementary surfaces overlapping with each of said projecting means extending beyond the center line of said nip, whereby the total extension of opposing projecting means traverses the entire height of said nip in unidirectional to form passages through the compressed bituminous material, said complementary surfaces being in juxtaposed relation and said passages having spaced parallel wall portions.

References Cited by the Examiner UNITED STATES PATENTS 1,014,424 1/1912 Troeger 189 X 1,756,328 4/1930 Andelin 189 2,599,894 6/1952 Campbell 107- 12 X 2,673,168 3/1954 Pascoe et al 18-9 2,917,821 12/1959 Fritsch 18-9 X 2,919,466 1/1960 Roemer 189 3,123,656 3/1964 Rochlin 18-9 X WILLIAM J. STEPHENSON, Primary Examiner.

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