JPH11181440A - Production of coke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing high strength cokes capable of increasing the content of a not-slightly-caking coal in a raw coal for coke making and using a less expensive method. SOLUTION: A raw coal for coke making comprising a coal of a high coal degree of >=1.5 in a vitrinite reflectance (Ro), which exhibits a coal degree, in an amount of 10-30 wt.%, and a caking coal and a not-slightly-caking coal of <1.5 in a vitrinite reflectance in an amount of 90-70 wt.% of the remaining part is dried to make the water content of 3-6 wt.%, and then carbonized. Further, caking coal is added in an amount of 1-10 wt.% based on the above raw coal, and they are carbonized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing coke for a blast furnace.

[0002]

2. Description of the Related Art The role of coke in the blast furnace method is as follows.
It is important to ensure ventilation and liquid permeability in the blast furnace. Therefore, high strength is required as a property of coke.

[0003] In the method of producing coke for iron making, conventionally, caking coal having a high caking property is made about 80 wt% or more, and non-fine caking coal having a low caking property is used for the remaining ca. 20 wt% or less. Coking coal is charged into a coke oven and carbonized to produce coke for blast furnaces. Non-coking coal has a large reserve of resources compared to coking coal, and because it is inexpensive, by increasing the proportion of non-coking coal in the coking coal, effective utilization of coal resources can be achieved. In addition, the cost of coking coal can be reduced.

However, if the ratio of caking coal in the raw coal is reduced and the ratio of non-fine caking coal is increased, the strength of coke decreases. Therefore, a method has been proposed in which the ratio of non-coking coal in the raw coal is increased from the prior art to produce high-strength coke.

For example, by adjusting the pulverized particle size of each coal while paying attention to the caking properties of the coal, the coking properties of the raw coal at the time of dry distillation are improved, and the ratio of non-fine caking coal is increased. As a method for performing this, there is a particle size adjustment method (hereinafter, referred to as a CPCP method). Regarding the method of grinding the coking coal,
Vol. 60, No. 653, p. 771 to 779. In the CPCP method, coal containing little inert and high quality vitrinite is coarsely pulverized to, for example, about -5 mm, while coal with much inert is reduced to about -2 mm or less by reducing the pulverized particle size to obtain a raw material at the time of carbonization. The purpose is to improve the caking properties of coal and improve coke quality. However, even in the CPCP method, the upper limit of the use ratio of the non-coking coal is about 10 wt%.

In addition, as a method of improving the coke strength by drying the coking coal charged to a coke oven to a water content of about 5 to 6% and charging the coke oven, a coal humidification process (hereinafter, referred to as "coal conditioning process") will be described. The method is described in Coke Note (Corporate Incorporated Association, edited by Fuel Association, 1988 edition), p. 136 mag. C
In the MC process, the coking density can be increased compared to the wet coal charging method by drying the coking coal charged into the coke oven to a water content of about 5 to 6%, so that the coke strength can be increased. It is. However, even in this method, the upper limit of the proportion of non-slightly caking coal is about 20 wt%.

Therefore, there is a need to develop a method for producing high-strength coke by using a large amount of inexpensive non-fine caking coal which has a large resource reserve.

[0008]

As described above, it has been desired to develop a method for producing a high-strength coke by an inexpensive method by increasing the proportion of non-coking coal in the raw coal. An object of the present invention is to provide a method for producing coke that solves such a problem.

[0009]

In order to solve the above-mentioned problems, the present invention provides: (1) 10 to 30 wt% of coal having a reflectance (Ro) of vitrinite indicating a degree of coalification of 1.5 or more. , The remaining 90
Coke production characterized by drying coking coal consisting of caking coal having a reflectance of less than 1.5 and non-fine caking coal having a reflectance of less than 1.5 to 70 wt% to dryness to a moisture content of 3 to 6 wt%. Method. (2) The method for producing coke according to (1), wherein 1 to 10% by weight of a binder is added to the raw coal and dry-distilled. It is.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The specific contents will be described below. FIG. 1 is a diagram showing a coke production process according to the present invention. 1 is a coal blending tank, 2 is a coal supply feeder, 3 is a dryer, 4 is a binder addition device, 5 is a binder tank, and 6 is a coke oven. The amount of coal supplied from the coal supply feeder 2 below the coal blending tank 1 is adjusted, and each coal in the raw coal is blended at a predetermined ratio. The raw coal is sent to the dryer 3 to dry the water to 3 to 6% by weight. afterwards,
By the binder addition device 4, the weight ratio to the raw coal is 1 to 1.
After adding 10 wt% of the binder, the mixture is sent to the coke oven 6 and charged into the coke oven.

In the coke making process shown in FIG. 1, the present inventors used a raw coal containing a large amount of non-coking coal to mix a raw coal by focusing on the reflectance (Ro) of vitrinite. The method of producing high-strength coke by pretreatment was studied in detail.

As shown in Table 1, the reflectance of vitrinite of each coal type is about 0.7 to 0.9 for non-coking coal, and about 0.9 for caking coal of medium coalification. Among the caking coals, high-rank coals are classified into about 1.5 or more.

As a result of intensive studies of the relationship between the reflectance of vitrinite and the coke strength of the coal blended into the raw coal, the present inventor has found that when blending high-rank coal with a reflectance of 1.5 or more, It has been found that an effect of improving coke strength can be obtained. Therefore, the reflectance of vitrinite of high-rank coal to be blended in the raw coal is limited to 1.5 or more.

However, high-rank coal having a vitrinite reflectance of 1.5 or more has a high expansion pressure generated during carbonization, and if it is blended in a large amount, it causes damage to the furnace wall of the coke oven carbonization chamber.

As a result of investigations by the present inventors, the coke strength is improved when 10 wt% or more of high-rank coal having a vitrinite reflectance of 1.5 or more is blended. But,
30 high coal coals with a vitrinite reflectance of 1.5 or more
If the content is more than wt%, the expansion pressure during the carbonization process becomes extremely high, and there is a possibility that the wall of the coke oven may be damaged.

Therefore, the blending ratio of the high-rank coal having a reflectivity of vitrinite of 1.5 or more is limited to 10 to 30 wt%.

As a result of diligent studies by the present inventor on the relationship between the water content of the raw coal and the coke strength, it was found that when the water content was dried to 6% or less, the coke strength was improved. Therefore, the water content of the raw coal is limited to 6% or less.

However, when the water content of the raw coal is dried to less than 3%, the amount of dust generated when the raw coal is sent to the coke oven is greatly increased. Therefore, the lower limit of the water content of the raw coal is limited to 3%.

The present inventors have examined in detail the relationship between coke strengths using coal having properties shown in Table 1.

[0020]

[Table 1]

As shown in FIG. 2 and FIG. 3, when the raw coal containing 10 to 30% by weight of coal having a reflectivity of vitrinite of 1.5 or more is dried to 3 to 6% and carbonized, Strength is improved.

Further, a binder is added to the raw coal in an amount of 1 to
After adding 10 wt%, the coke was carbonized in a coke oven to produce coke. As a result, the strength of the coke was greatly improved.

In the present invention, types of the binder include tar, soft pitch, tar heavy oil, petroleum heavy oil and the like.

The water content of raw coal obtained by blending 10 to 30 wt% of high-rank coal having a vitrinite reflectance of 1.5 or more is 3
When coke is produced by dry distillation after drying to ~ 6%, cracks inside the coke mass are reduced.
As shown in an example in FIG. 4, DI ¹⁵⁰ _6-15, which is an index indicating the magnitude of strength decrease due to volume destruction of coke, decreases. Furthermore, as a result of adding a binder to the raw coal in an amount of 1 to 10% by weight and dry-distilling in a coke oven to produce coke, DI as an index of the abrasion resistance of the coke is shown as an example in FIG. ¹⁵⁰ ₆ also improved, the coke drum strength (D
I ¹⁵⁰ ₁₅ ) was found to be greatly improved.

The amount of the binder added is 10 wt.
%, The charging density at the time of charging coal into the coke oven is significantly reduced, which causes a reduction in coke strength. If the amount of the binder is less than 1 wt%, the effect of improving the coke strength is not clearly recognized. Therefore,
The amount of binder added is limited to 1 to 10 wt%.

As a result of the above examination, coal having a reflectance (Ro) of vitrinite, which is an index of the degree of coalification, of 1.5 or more is regarded as one coal.
The water of the coking coal containing 0-30 wt% is dried to 3-6%,
By adding a binder in an amount of 1 to 10% by weight and dry-distilling, it is possible to produce high-strength coke, and as a result, it has become possible to significantly reduce the cost of producing coke.

In the present specification, the reflectance of vitrinite is J
The value of the average maximum reflectance of vitrinite obtained by measuring using a polarizing microscope by the reflectance measurement method of coal described in ISM8816 is shown.

As used herein, coke strength refers to JIS K
2151 shows the results obtained by measuring the coke sample by a drum strength test method described in No. 2151 and expressing the coke sample by a weight ratio remaining on a 15 mm sieve after 150 rotations.

[0029]

EXAMPLE 1 In accordance with the method of the present invention, coke was produced using an experimental apparatus capable of simulating the coke production process shown in FIG. The raw coal is 20 wt% of coal A, which is a caking coal having a high degree of coalification having a reflectivity of vitrinite of 1.55 as shown in Table 1, and coal D, which is a caking coal having a medium degree of coalification (reflectance 1). .20) and 40 wt% of non-coking coal G coal (reflectivity 0.76) were used. The coking coal is dried in a dryer to 3 wt.
%, And put in a carbonization furnace at 1,150 ° C.
It was distilled in 5 hours. As a result, as shown in FIG. 2, the strength of the coke was as high as 84.0%, and the coke had sufficient strength as blast furnace coke.

Example 2 According to the method of the present invention, FIG.
The coke was produced using an experimental device capable of simulating the coke production process shown in FIG. The raw coal is 20 wt% of coal A, which is a caking coal having a high degree of coalification having a reflectivity of vitrinite of 1.55 as shown in Table 1, and 40 wt% of coal D, which is a caking coal of medium coalification. , 4 coals of non-coking coal G
0 wt%, each of which was used. After drying the raw coal with a dryer to a moisture content of 3 wt%, 3 wt% of soft pitch was added to the raw coal as a binder, and then put into a dry distillation furnace and carbonized at 1,150 ° C. for 17.5 hours. . As a result, as shown in FIG. 2, the strength of the coke was as high as 85.6%, which was sufficient for blast furnace coke.

(Comparative Example 1) Coal D which is a caking coal having a medium coalification degree shown in Table 1 is 60 wt%, and G which is a non-fine caking coal.
40 wt% of charcoal and the raw coal blended in each were placed in a carbonization test furnace in a state of 6 wt% in moisture and carbonized at 1.150 ° C. for 18 hours. As a result, as shown in FIG. 2, the strength of the coke was as low as 80.2%, which was insufficient for the blast furnace coke. (Comparative Example 2) 60% by weight of coal D, which is a caking coal having a high degree of coalification, whose properties are shown in Table 1, and 40% by weight of coal G, which is a non-fine caking coal
The tar was added to the raw coal in a state where the raw coal thus mixed was dried to a moisture content of 3 wt%, and then placed in a carbonization test furnace and carbonized at 1.150 ° C. for 17.5 hours.
As a result, as shown in FIG. 2, the coke strength was 82.8.
%, Which is insufficient for blast furnace coke.

(Embodiment 3) According to the method of the present invention, FIG.
The coke was produced using an experimental device capable of simulating the coke production process shown in FIG. The raw coal is 10 wt% of coal A, which is a caking coal having a high degree of coalification having a reflectivity of vitrinite of 1.55 as shown in Table 1, 40 wt% of coal D, which is a caking coal having a medium degree of coalification, 50 charcoal, non-coking coal G
wt%, each of which was used. After drying this raw coal with a dryer to a moisture content of 3 wt%, tar is added as a binder to the coal at 3 wt%, and then put into a dry distillation furnace to obtain 1,
It was carbonized at 150 ° C for 17.5 hours. As a result, as shown in FIG. 3, the strength of the coke was as high as 83.3%, and the coke had sufficient strength as blast furnace coke.

(Embodiment 4) According to the method of the present invention, FIG.
The coke was produced using an experimental device capable of simulating the coke production process shown in FIG. The raw coal is 10 wt% of coal A, which is a caking coal having a high degree of coalification having a reflectivity of vitrinite of 1.55 as shown in Table 1, 40 wt% of coal D, which is a caking coal having a medium degree of coalification, 50 charcoal, non-coking coal G
wt%, each of which was used. The raw coal was dried with a dryer to a moisture content of 3 wt%, and then 3 wt% of soft pitch was added to the coal as a binder, and then placed in a dry distillation furnace and carbonized at 1,150 ° C. for 17.5 hours. As a result,
As shown in FIG. 3, the strength of the coke was as very high as 85.0%, and had sufficient strength as blast furnace coke.

(Comparative Example 3) 10 wt% of coal A, which is a caking coal having a high degree of coalification, and 40 wt% of coal D, which is a caking coal having a medium degree of coalification, whose properties are shown in Table 1. 50 charcoal G charcoal
wt%, and the raw coal blended respectively were placed in a carbonization test furnace in a state of 7 wt% of moisture and carbonized at 1.150 ° C. for 18 hours.
As a result, as shown in FIG.
%, Which is insufficient for blast furnace coke.

(Comparative Example 4) Coal D, a caking coal of medium coalification, whose properties are shown in Table 1, was 50 wt%, and G, a non-fine caking coal, was G.
The coal was dried at 50% by weight, and the raw coal blended was dried to 3% by weight, and 3% by weight of tar was added. The resultant was put into a carbonization test furnace and carbonized at 1.150 ° C. for 17.5 hours. As a result, as shown in FIG. 3, the strength of the coke was as low as 82.3%, and the strength was insufficient for blast furnace coke.

[0036]

As described above, the present invention makes it possible to produce coke having high strength even if a large amount of non-coking coal is used. The technical and economic effects of the present invention are very large.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method for producing coke to which the present invention is applied.

FIG. 2 is a diagram showing the effect of improving coke strength when the present invention is applied to Embodiments 1 and 2.

FIG. 3 is a diagram showing the effect of improving coke strength when the present invention is applied to Examples 3 and 4.

FIG. 4 is a diagram showing the effect of the present invention, showing the effect of improving the volume fracture strength of coke when high-rank coal is blended.

FIG. 5 is a diagram showing the effect of the present invention, and is a diagram showing the effect of improving the surface fracture strength of coke when high-rank coal is blended.

[Explanation of symbols]

 1: Coal blending tank 2: Coal supply feeder 3: Dryer 4: Binder addition device 5: Binder tank 6: Coke oven

Claims (2)

[Claims] 1. A method according to claim 1, wherein the reflectance (Ro) of the vitrinite having a degree of coalification includes 1.5 to 30% by weight of coal.
The remaining 90 to 70 wt% of the vitrinite has a reflectance of 1.
A method for producing coke, comprising drying raw coal composed of less than 5 caking coals and non-micro caking coals to dry-evaporate to a moisture content of 3 to 6 wt%. 2. A binder of 1 to 10% by weight based on raw coal.
The method for producing coke according to claim 1, wherein the coke is added and carbonized.