Method for operating blast furnace
AssigneeJfe Steel Corporation
InventorsYoshifumi Kobashi, Naoshi Yamahira, Toshiki Tsuboi
Life of this patent
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Abstract
A method for operating a blast furnace with which, even in the case where there is an increase in the powder ratio of coke to be charged into the blast furnace, it is possible to achieve the stabilization of blast furnace operation. The method includes blowing air through a tuyere disposed in a lower part of the blast furnace, successively measuring a particle size distribution of coke transported to the blast furnace, and adjusting at least one of a blast volume and a coke ratio in accordance with an index derived from the particle size distribution.
Claims2
A method for operating a blast furnace, the method comprising:
- transporting coke to the blast furnace;
- blowing air through a tuyere disposed in a lower part of the blast furnace;
- successively measuring a particle size distribution of the coke transported to the blast furnace;
- determining a powder ratio of the coke from the particle size distribution, the powder ratio of the coke being a ratio of a mass of coke powder in the coke having a particle diameter of 5 mm or less to a total mass of the coke;
- determining whether an actual variation in the powder ratio within a length of time is equal to or more than a first threshold value and less than a second threshold value;
- determining whether the actual variation in the powder ratio within the length of time is equal to or more than the second threshold value, wherein:
- the first threshold value is a first predetermined variation in the powder ratio within the length of time that is set in advance, and
- the second threshold value is a second predetermined variation in the powder ratio within the length of time that is set in advance, the second threshold value having an absolute value that is more than an absolute value of the first threshold value;
- decreasing a blast volume of the air blown through the tuyere without changing the coke ratio, the coke ratio being a weight of coke used to produce one ton of pig iron, when determining that the actual variation in the powder ratio within the length of time is equal to or more than the first threshold value and less than the second threshold value;
- and
- increasing the coke ratio based on the powder ratio when determining that the actual variation in the powder ratio within the length of time is equal to or more than the second threshold value.
A method for operating a blast furnace, the method comprising:
- transporting coke to the blast furnace;
- blowing air through a tuyere disposed in a lower part of the blast furnace;
- successively measuring a particle size distribution of the coke transported to the blast furnace;
- determining a void fraction of a coke-packed layer in the blast furnace from the particle size distribution;
- decreasing a blast volume of the air blown through the tuyere when an actual variation in the void fraction within a length of time is equal to or less than a first threshold value and more than a second threshold value, wherein:
- the first threshold value is a first predetermined variation in the void fraction within the length of time that is set in advance, and
- the second threshold value is a second predetermined variation in the void fraction within the length of time that is set is advance, the second threshold value having an absolute value that is more than an absolute value of the first threshold value;
- and
- increasing the coke ratio based on the void fraction, the coke ratio being a weight of coke used to produce one ton of pig iron, when the actual variation in the void fraction within the length of time is equal to or less than the second threshold value.
Dependencies are inferred from the claim text.