Fuel and related compositions – Coal treating process or product thereof
Patent
1997-08-28
1999-04-27
Howard, Jacqueline V.
Fuel and related compositions
Coal treating process or product thereof
44626, 75751, 75760, 75770, 75771, C10L 500
Patent
active
058976744
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method for manufacturing coal agglomerates for use in a direct iron smelting reducing furnace. More specifically, the present invention relates to a method for manufacturing coal agglomerates, in which fine coal is agglomerated at a high temperature.
DESCRIPTION OF THE PRIOR ART
The coal which is used in a direct smelting reducing furnace as an energy source has to have a uniform particle size (8-35 mm).
However, 50% or more of the coal which is supplied for use in the direct smelting reducing furnace is fine coal having a particle size of 8 mm or less. This fine coal is flown into the generator gas line when it is put into the smelting furnace, and therefore, the fine coal becomes useless.
That is, the supplied ordinary coal is subjected to a particle size classification, and the agglomerates having a size of 8 mm or more are put into the smelting reducing furnace after dewatering them. However, the fine coal having a particle size of 8 mm or less cannot be used.
Therefore, if the fine coal having a particle size of 8 mm or less is to be used in the smelting reducing process, it has to be first agglomerated.
A method of agglomerating the fine coal is disclosed in U.S. Pat. No. 3,869,350 which relates to a method for heat-treating a coking coal. In this method, the fine coal is injected into a tube in which a high temperature gas flows, thereby agglomerating the fine coal.
However, in the above described agglomerating method, there is the disadvantage that a high temperature gas supply device is required, the temperature rising rate having to be 100.degree. C./sec.
SUMMARY OF THE INVENTION
In order to solve the above described problem, the present inventor carried out research and experiments, and based on the result of the research and experiments, the present invention is proposed.
Therefore it is an object of the present invention to provide a method for manufacturing coal agglomerates for use in a direct smelting reducing furnace, in which the self agglomerating trend of coal owing to its self sticking property during a thermal decomposition process is utilized, so that the fine coal can be agglomerated at a high temperature in a simple manner.
It is another object of the present invention to provide a method for manufacturing coal agglomerates for use in a direct smelting reducing furnace, in which anthracite or low free swelling coal having a low free swelling index is mixed with the fine coal, and the mixture is agglomerated at a high temperature, thereby turning the low quality coal to useful purpose.
In achieving the above objects, the method for manufacturing coal agglomerates for use in a direct smelting reducing furnace according to the present invention is characterized in that a fine coal having a free swelling index of 3.0 or more and a particle size of 8 mm or less is maintained at 600.degree. C. or over for 5 minutes or more, thereby manufacturing coal agglomerates for use in a direct smelting reducing furnace.
In another aspect of the present invention, the method for manufacturing coal agglomerates for use in a direct smelting reducing furnace according to the present invention is characterized in that a fine coal having a free swelling index of 3.0 or more and a particle size of 8 mm or less is mixed with 70 weight % of anthracite or allow free swelling coal, and is maintained at 600.degree. C. or over for 5 minutes or more, thereby manufacturing coal agglomerates for use in a direct smelting reducing furnace.
BRIEF DESCRIPTION OF THE DRAWINGS
The above object and other advantages of the present invention will become more apparent by describing in detail the preferred embodiment of the present invention with reference to the attached drawings in which:
FIG. 1 is a graphical illustration showing the variation of the compressive strength versus the maintaining time during the agglomeration of the fine coal;
FIG. 2 is a graphical illustration showing the variation of the compressive strength versus the maintaining temperat
REFERENCES:
patent: 1810070 (1931-06-01), Bunce
patent: 3869350 (1975-03-01), Goossens et al.
patent: 4234320 (1980-11-01), Verschuur
patent: 4770766 (1988-09-01), Keller, Jr. et al.
patent: 4830637 (1989-05-01), Wasson
Cho Min Young
Jung Young Chae
Lee Dal Hoi
Howard Jacqueline V.
Pohang Iron & Steel Co. Ltd.
Research Institute of Industrial Science & Technology
Voest-Alpine Industrieanlagenbau
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