JPH06136363A - Formed coke - Google Patents

Abstract

PURPOSE:To obtain a formed coke which is selectively broken in carbonization or handling and thus prevents the decrease in mean particle size in charging a blast furnace by combining and uniting a plurality of coal briquettes having shapes of pillow, cylinder, oval, polygonal column, and sphere. CONSTITUTION:If necessary, a foreign master such as a ceramic used as a blast furnace component is inserted into the insides of a plurality of coal briquettes which have shapes of pillow, cylinder, oval, and sphere and have notches if necessary. The briquettes are then partly combined and integrally molded, or are arranged on a platy coal and bonded.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to the shape of a molding coke used in a blast furnace.

[0002]

BACKGROUND OF THE INVENTION Blast furnace coke functions as a reducing material, a heat source, and a supporting material for maintaining air permeability, and is essential in the blast furnace ironmaking method. In order to play a role as a breathable holding material, it is necessary to have sufficient strength to withstand the pressure of the packed bed in the furnace and abrasion resistance for minimizing the generation amount of fine powder. In order to produce a coke having such a high strength, it is necessary to have a certain proportion or more of strong coking coal in the raw material coal. However, the production of strong coking coal is subject to regional, quantitative and price restrictions. In terms of resources, depletion is expected in the near future.

Against this background, a coke production method using steam coal, which has a small amount of a caking component, has recently attracted attention. As one of them, a so-called molding coke is used on a trial basis by adding a binder such as pitch, asphalt, tar and the like to steam coal, press-molding it, and dry-distilling it to form a coke. Has been.

For example, in 1978, the "Continuous Forming Coke Research and Development Committee" was established within the Japan Iron and Steel Federation, and Kawasaki Steel, Kobe Steel, Nippon Steel, Nippon Steel Pipe (currently NK)
K) conducted joint research (Okuhara: Steel Industry, 8
(1984)). 200 ton in this joint research
/ Day development of the carbonization method using a pilot plant and the results of the use test in a blast furnace are disclosed (Okuhara et al .: Iron and Steel, 65 (1979), S584 to S587, etc.). The shape of the molding coke used there was a vertically long "pillow-shaped" with rounded ends as schematically shown in the plan view of FIG.
belongs to.

[0005]

When the formed coal is subjected to dry distillation, it melts, expands and shrinks in the process of coking, so that it is crushed or cracked inside. If a crack occurs inside, crush it during subsequent handling.
Due to the crushing during the dry distillation and handling, the particle size of the molded coke during use of the blast furnace is reduced, and the ventilation resistance is increased during the operation of the blast furnace. Even if the molded coke does not have such a particle size reduction, the packing density in the furnace is higher than that of the conventional coke and the bulk density is higher, so that the layer thickness and voids are reduced. There was a defect that the holding power of air permeability was decreased, the blast pressure and the pressure loss were increased, and the operation of the blast furnace became unstable. Therefore, the reduction of the particle size due to the above-mentioned crushing becomes a serious problem in the operation of the blast furnace, especially from the viewpoint of the increase of the ventilation resistance.

[0006]

According to the present invention, a plurality of forming coals having a basic shape of a pillow type, a column type, an egg type, a polygonal column type, and a spherical type are combined with each other to form an integral shape. It is characterized by

By forming the shaped coal of the present invention into a shape having a portion where stress concentration is likely to occur, it is preferentially broken at that portion during carbonization or handling, and the decrease of the average particle diameter at the time of charging the blast furnace is prevented. Is what you can do.

[0008]

The function of the present invention will be described in more detail below.

As a result of observing the molded coke before breaking, for example, with respect to the molded coke having a pillow type basic shape with rounded ends as shown in FIG. As shown in Fig. 9, there was an internal crack in the minor axis direction, and it was found that there is a very high probability of fracture from here during handling. Furthermore, when the generation process of internal cracks was investigated, it was found that it was mainly due to thermal stress during carbonization of the forming coal. Based on this knowledge, it is possible to prevent a decrease in the average particle size during blast furnace charging by using coal briquette that has a portion where stress concentration is likely to occur and preferentially destroying that portion during carbonization or handling. I came to discover that it was possible.

The details will be described below.

The shape having a portion where stress concentration is likely to occur is, for example, the pillow type shown in FIG. 8, the cushion type shown in FIG. 10, the mirror rice cake type shown in FIG. 11, the column type shown in FIG. 12, the polygonal column type shown in FIG. 1, FIG. 2, FIG. 3, and FIG. 4 in comparison with the basic three-dimensional shape shown in the example of the egg shape, which can be used as a molding coke for a blast furnace even in the ratio of dividing into a single piece or a plurality of pieces. 5 and 6 and FIG. 7 are processed. Here, FIG. 1, FIG. 2 and FIG. 3 show an example of a system in which a plurality of basic shapes of the present invention are combined,
FIG. 1 shows an example of a combination of two pillow types, FIG. 2 shows an example of a combination of four pillow types, and FIG. 3 shows an example of a combination of two rectangular parallelepiped types.

FIGS. 4 and 5 show an example of a system in which a notch is provided in the basic shape. FIG. 4 shows a notch in the circumferential direction of a cylindrical type, and FIG. FIG. 6 shows an example in which a material is inserted, and a semi-cylindrical type is arranged on a plate. When stress is generated, stress is concentrated on the cutout portion or the boundary portion of the combination, and by preferentially crushing from this portion, crushing from other portions can be suppressed. As a result, at the time of charging in the blast furnace, the proportion of the molding coke that maintains the basic shape is increased, and it is possible to prevent the decrease in particle size due to conventional crushing.

The cause of the stress is considered to be thermal stress during carbonization and mechanical stress during handling. Even if crushing does not occur during carbonization, the probability of crushing from that part during handling becomes extremely high due to the occurrence of cracks on the bonding surface. Further, even if it is not crushed by either dry distillation or handling, the ventilation resistance tends to decrease when the blast furnace is used, and there is no problem in operation.

The shapes of the basic shapes are shown in FIGS.
It is not limited to those shown in FIGS. 11, 12, 13, and 14, and is determined based on the formability of the forming coal, the carbonization efficiency, the conditions for using the blast furnace, and the like.

[0015]

EXAMPLE A shape obtained by combining two basic shapes shown in FIGS. 8, 10, 11, 12, 13 and 14 (combined formulas 1 to 3 in Table 1 are the same), width 3 mm, depth 5 m.
Shape with m notches (notches 1 and 2), 1 mm thick CaO and asphalt mixture inserted in the center (different material insertion type), 3 mm thick plate-like charcoal with 3 mm spacing Experiments were carried out using a molding coke obtained by dry-distilling shaped coal having a shape (plate chocolate type) arranged in (1) and a shape (composite formulas 1 to 3) in which these were combined. The average particle size in the basic shape is 50 mm in all cases. The combination type uses a twin roll with an aluminum alloy mold whose split surface is the surface perpendicular to the combination surface, and the notch type is a notch with a stainless steel blade after molding with the twin roll. Parts are given. In the dissimilar material insertion type, the formed coal of the basic shape was divided into halves, the mixture of CaO and asphalt was applied to one of the divided surfaces so that the thickness was 1 mm, and the other formed coal was joined. Further, in the plate chocolate type, after molding with a die having a shape after joining, it was pressed using a cold isostatic press. Each of the forming coals was subjected to dry distillation at 900 ° C to obtain a forming coke. The average particle size on the outlet side of the storage tank is shown in Table 1 together with the results of the current molding coke for comparison.

From the above, it was found that the average particle size at the time of charging the blast furnace when the example of the present invention was used was significantly larger than that of the comparative example.

[0017]

[Table 1]

[0018]

As described in detail above, the present invention is
Pillow type, column type, egg type, polygonal column type and a combination of a part of each of a plurality of forming coal based on spherical shape,
It is characterized by having an integrated shape.

In the present invention, by forming the molding coke into a shape having a portion where stress concentration is likely to occur, preferentially destroying a portion of the molding coke where stress concentration is likely to occur during carbonization or handling. It became possible to prevent the rise of ventilation resistance by increasing the average particle size when charging the blast furnace.

[Brief description of drawings]

FIG. 1 is a schematic view showing a molding coke (combination formula 1) having a shape in which two pillow molds are combined at the abdomen.

FIG. 2 is a schematic view showing a molding coke (combination formula 2) having a shape in which four pillow molds are combined at their ends.

FIG. 3 is a schematic diagram showing a molding coke (combination formula 3) having a shape in which two rectangular parallelepipeds are displaced and combined.

FIG. 4 is a schematic view showing a molding coke (notch type 1) having a shape in which a notch portion is provided in the circumferential direction of a cylindrical type.

FIG. 5 is a schematic view showing a molding coke (notch type 2) having a shape in which a notch is provided in the axial direction of a cylindrical type.

FIG. 6 is a schematic view showing a molding coke (dissimilar material insertion type) in which a dissimilar material is inserted into the center surface of a pillow shape.

FIG. 7 is a schematic view showing a forming coke (plate chocolate type) in which a semi-cylindrical type is arranged on a plate-shaped charcoal.

FIG. 8 is a plan view showing an example (pillow shape) of the shape of a basic molding coke used in a test by the Japan Iron and Steel Federation.

FIG. 9 is a schematic view showing internal cracks in a molding coke.

FIG. 10 is a schematic view showing an example (cushion type) of a molding coke having a basic shape.

FIG. 11 is a schematic view showing an example (kagami-mochi type) of a molding coke having a basic shape.

FIG. 12 is a schematic view showing an example (cylinder type) of a molding coke having a basic shape.

FIG. 13 is a schematic view showing an example (polygonal prism type) of a molding coke having a basic shape.

FIG. 14 is a schematic view showing an example (egg shape) of a molded coke having a basic shape.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeshi Uchiyama, 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Inside the Technical Research Division, Kawasaki Steel Co., Ltd. (72) Hiroshi Itaya, 1 Kawasaki-cho, Chuo-ku, Chiba-shi Kawasaki Steel Corporation Technical Research Division

Claims (4)

[Claims] 1. A molding core characterized by having an integrated shape by combining parts of a plurality of molding coals each having a basic shape of pillow type, column type, egg type, polygonal column type and spherical type. Cous. 2. A forming coke, which has a shape obtained by forming a notch in the forming coal of the basic shape according to claim 1. 3. A molding coke, characterized in that a different kind of material such as ceramics based on a blast furnace slag component is inserted into the molding coal of the basic shape according to claim 1. 4. A forming coke, wherein the forming coal having the basic shape according to claim 1 is arranged and joined on a plate-shaped charcoal.