JPH10273672A - Charging of coal into coke oven capable of producing coke with large size - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for suitably charging coal into a coke oven for producing coke with large size without reducing coking coal characteristics and operating efficiency and without the need of any caking additive, by adding a specific additive to only coals destined to be charged along the side walls of the coke oven in its crosswise direction. SOLUTION: This method is conducted as follows: when coal 5 is to be dropped and charged into a carbonizing chamber 3 in a chamber type coke oven capable of producing coke with large size, an additive 31 (e.g. powder coke, petroleum coke, or anthracite with a granular size of <=1 mm) for increasing coke size is added to only the coal 5 to be charged along the side walls 22a and 22b in the crosswise direction of the coke oven e.g. through an additive feed pipe 8 so constituted as to be branched above the side walls 22a and 22b partitioned by partition plates 4 in a charging cylinder 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing metallurgical coke using a chamber furnace, and more particularly, to a method for charging coal into a coke oven for producing coke having a large particle size.

[0002]

2. Description of the Related Art In the production of coke for metallurgy, the goal is to produce coke with a large particle size. Is adjusted.

[0003] Generally, in the production of coke, the particle size of coke is determined by the relative relationship between the thermal stress generated by the shrinkage of semi-coke after resolidification and the substrate strength in the carbonization process of coal. That is, when the thermal stress exceeds the substrate strength, a crack is generated and propagated in the coke, and the coke is fragmented. Therefore, when the generated thermal stress is small or the substrate strength is large, the particle size of the coke increases. On the other hand, the thermal stress increases when the amount of shrinkage after re-solidification is large or when the temperature gradient after re-solidification is high. The former occurs when the degree of coalification of the coal blend is low, and the latter occurs when the operating rate of the coke oven is high. In addition, the substrate strength increases as the degree of coalification and the softening and melting properties increase. Therefore, it is theoretically possible to adjust the coke particle size by controlling the degree of carbonization, softening and melting properties of the coal and the operating rate of the coke oven. It is also known that the particle size is changed by adding an inert substance such as coke breeze, petroleum coke, and anthracite.

[0004]

However, in actual coke oven operation, the coke strength is controlled so as to maintain the coke strength at a constant value, and the degree of coalification and the softening and melting properties are factors determining the coke strength. It is difficult to change these greatly for adjustment of coke particle size. In addition, since the operation rate is determined by the production plan, the degree of freedom is still low. Therefore, it is theoretically thought that the coke particle size can be adjusted by the above-mentioned factors, but it is not possible in practice. Further, simply adding an inert substance such as coke breeze generally lowers the coke strength, so that it is necessary to separately add a binder or the like for maintaining the strength, which has a disadvantage of increasing the cost. The present invention produces coke of economically and rationally large particle size without changing the properties of coking coal, without changing the operation rate, and without adding a binder for maintaining strength. It is an object of the present invention to provide a method for charging coal.

[0005]

Means for Solving the Problems The inventors of the present invention have reported that since the carbonization of coke produced in a chamber furnace proceeds by heat transfer from the furnace wall, the rate of temperature increase on the wall side is 3 to 3 times higher than that on the center side. As high as four times, the thermal stress increases, and crack nuclei are generated on the wall side and propagate toward the center side to determine the coke particle size. Therefore, if only the thermal stress on the wall side can be reduced, the coke It is possible to suppress grain refinement, and, if an inert substance such as coke breeze is added to the high thermal stress wall side, it is possible to reduce crack nuclei through dispersion of generated stress. Although the addition of an inert substance is inconvenient because it lowers the coke strength, the wall side has a higher heating rate and therefore has more strength than the center side, and even if the strength of that part decreases slightly, the overall Knowing that the strength drop is almost negligible, Invention has been completed.

Accordingly, the present invention provides a method of producing coke having a large particle size, in which coal is dropped and charged into a carbonization chamber of a coke oven, and the coal is charged on the wall side in the coke oven width direction of the coal. An additive for increasing the coke particle size is added only to the coal to be charged. In the practice of the present invention, an additive that increases the coke particle size is selected from and used as an inert substance selected from coke breeze, petroleum coke and anthracite.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, based on the above findings, when coal is dropped and charged into the coking chamber of a coke oven type coke, the coal charged on the wall side in the width direction of the coke oven is treated. Additives which only increase the coke particle size are added. Although it is impossible to reduce the thermal stress itself in the current room furnace system other than lowering the operation rate, inert substances such as coke breeze have a difference in the amount of shrinkage from coke produced from coal. At the boundary of
It takes advantage of the fact that microcracks are generated at the interface, stress is relaxed, and crack nucleation and growth are suppressed.

As the additive for increasing the coke particle size, inert substances such as coke breeze, petroleum coke, and anthracite can be suitably used. Further, as will be apparent from the following experiments, the range in which the above-mentioned additive is added is preferably on the wall side having a width of about 1/8 of the furnace width, and the particle size of the additive is preferably 1 mm or less. The addition rate may be adjusted according to the particle size required for metallurgical coke.

Hereinafter, the present invention will be specifically described based on examples and experimental examples. As shown in FIG. 1, the coal 5 is carbonized from a coal hopper 10 through a table feeder 11, a charging cylinder 2, and a charging hole of a coke oven (the inner diameter of which is equal to the outer diameter of the charging cylinder 2). It is charged into the room 3. At this time, the inside of the charging cylinder 2 is separated by the partition plate 4 into a central portion 21, a wall portion 22a,
2b, and an additive for increasing the coke particle size is added only to the coal charged on the wall side of the carbonization chamber. Specifically, the additive 31 is added only to the coal flowing on the wall sides 22a and 22b from the additive hopper 6 via the screw feeder 7 and the additive supply pipe 8. For this reason, the additive supply pipe 8 of the additive addition device 1 is configured so as to be branched at the upper part (or inside) of the wall portions 22a and 22b of the charging cylinder 2 partitioned by the partition plate 4. Side 22a, 2
It is preferable that the additive 31 can be added only to the coal flowing in the 2b. However, the above object can be achieved by omitting the partition plate 4 and sufficiently pointing the opening of the additive supply pipe 8 toward the wall of the charging cylinder 2.

FIG. 2 is a perspective view of a model charging device for confirming the effect of the coal charging method according to the present invention. In this figure, the symbols of the devices are the same as those of the actual device shown in FIG. 1 for convenience. In this model device, coal is charged into the coking chamber 3 under the same conditions as the actual machine, the state of the charged coal is investigated, and the retort for carbonization (width 375 x length 410 x height 290 (unit mm)) ) Is set, the coal charged by the present model charging apparatus is carbonized, and properties such as coke particle size strength can be measured.

Table 1 shows the properties of an additive (using coke breeze as an inert substance) for increasing the coke particle size used in an experiment for confirming the effects of the present invention using the above model charging apparatus. , Table 2 shows charging conditions when the retort for carbonization is set in the model charging device and carbonization to be deposited in the model device, properties of the wall-side deposited coal,
These are the results of comparing the characteristic values of the product coke with those charged and carbonized under ordinary conditions. When the coal charging method according to the present invention is used, the volatile content of coal on the wall side in the furnace width direction is lower than that of the comparative example, the ash content is increased, and the coke particle size is larger than that of the comparative example. I have. However, there is no significant difference in strength.

[0012]

[Table 1]

[0013]

[Table 2]

FIG. 3 is a graph showing the relationship between the portion within 100 mm from the wall side and the 100 mm center portion when 1.5% of an additive for increasing the coke particle size is added only to the 50 mm wall side according to the present invention. It is a comparison of the coke strength. From this figure, the strength of the portion within 100 mm from the wall side is slightly deteriorated when the additive is added, but originally,
Since the portion had high strength, it can be seen that there is no problem as a product coke. FIG. 4 is a result of investigating to what extent it is effective to add the additive from the wall side. In order to prevent the influence of the decrease in the coke strength from occurring, the area within about 100 mm from the wall side is required. It can be seen that it is desirable to add the additive within about 50 mm. When this value is converted into a ratio with respect to the width of the coke oven carbonization chamber, it is within about 1/4 and 1/8, respectively. Therefore, in the present invention, the addition range of the above-mentioned additives is 1/4 of the furnace width from the furnace wall. Within, preferably within 1/8. FIG. 5 shows the relationship between the additive addition rate (relative to coal, weight%), the coke strength of the product coke, and the average coke particle size when the additive is added to a portion within 50 mm on the wall side. It can be seen that the increase in the average coke particle size is remarkable even in this range, while the addition ratio is unchanged up to 1.5%. Therefore, the additive rate of the additive may be determined according to the characteristic value of the metallurgical coke, but is generally preferably 1.5% or less.

[0015]

According to the present invention, it is possible to increase the coke particle size without impairing the coke strength and without impairing the operation rate (operating rate of the coke oven). As a result, the air permeability of the blast furnace was improved, and the productivity was greatly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a coke oven charging apparatus to which the present invention is applied. (A) is a longitudinal sectional view, (b) is
(A) FIG.

FIG. 2 is a perspective view of a model device used for research on a coal charging method according to the present invention.

FIG. 3 shows the difference in coke strength between addition and non-addition of coke breeze within 100 mm from the wall side and 100 m at the center.
FIG. 4 is a comparison diagram showing the coke strength of a portion within m.

FIG. 4 is a graph showing a relationship between an additive range of an additive for increasing coke strength and product coke characteristics.

FIG. 5 is a graph showing the relationship between the rate of addition of a coke strength increasing additive to the coke oven wall side and product coke characteristics.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Additive addition apparatus 2 Charging cylinder 3 Carbonization room 4 Partition plate 5 Coal 6 Additive hopper 7 Screw feeder 8 Additive supply pipe 10 Coal hopper 11 Table feeder 21 Central part 22a, 22b Wall side 31 Additive

Claims (2)

[Claims] When the coal is dropped and charged into a coking chamber of a coke oven type coke oven, the coke particle size is increased only for the coal of the coal charged on the wall side in the coke oven width direction. A method of charging coal into a coke oven capable of producing coke having a large particle size, characterized by adding an additive. 2. The coke oven according to claim 1, wherein the additive for increasing the coke particle size is an inert substance selected from coke breeze, petroleum coke and smokeless ash. How to charge coal to