Method for preparing coal for coke making

Patent metadata

Field	Value
Publication number	US-9708558-B2
Application number	US-201314375271-A
Country	US
Kind code	B2
Filing date	Feb 25, 2013
Priority date	Feb 29, 2012
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

Method for preparing coal for coke making includes controlling particles size of coal or caking additive before arriving at the plant so particles content having diameter of 6 mm or more in the coal or caking additive reaches 30% by mass or less when the coal or caking additive has permeation distance of 15 mm or more. In another method, the relationship between a critical permeation distance and Gieseler maximum fluidity is obtained using permeation distances and Gieseler maximum fluidity values of one or more brands of coal or caking additive, particles size of coal or caking additive is controlled before arriving at the plant so particles content having diameter of 6 mm or more in coal or caking additive reaches 30% by mass or less when permeation distance of coal or caking additive is larger or equal to a critical permeation distance calculated from the Gieseler maximum fluidity.

First claim

The invention claimed is:

1. A method for preparing coal for coke making, in which an individual brand of coal or caking additive is prepared at a time prior to arrival at a coke plant, the individual brand of coal or caking additive being used alone or in mixture with another coal as a raw material for coke making,
wherein, when the individual brand of coal or caking additive has a permeation distance of 15 mm or more, a size of particles of the individual brand of coal or caking additive is controlled at the time prior to arrival at the coke plant so that a content of particles having a diameter of 6 mm or more in the individual brand of coal or caking additive reaches 30% by mass or less, the permeation distance being measured by a method including the following steps (A) to (D):
(A) crushing the individual brand of coal or caking additive until a content of particles having a diameter of 2 mm or less reaches 100% by mass and then packing a vessel with the individual brand of coal or caking additive that has been crushed at a bulk density of 0.8 g/cm 3 and at a thickness of 10 mm to prepare a sample;
(B) arranging glass beads having a diameter of 2 mm on the sample at a thickness of the permeation distance or more;
(C) while applying a load of 50 kPa to an upper portion of the glass beads, performing heating in an inert gas atmosphere from room temperature to 550° C. at a heating rate of 3° C./min; and
(D) measuring a permeation distance of the softened sample that has permeated a layer composed of the glass beads.

2. A method for preparing coal for coke making, in which an individual brand of coal or caking additive is prepared at a time prior to arrival at a coke plant, the individual brand of coal or caking additive being used alone or in mixture with another coal as a raw material for coke making,
wherein, when the individual brand of coal or caking additive has a permeation distance of 15 mm or more, a size of particles of the individual brand of coal or caking additive is controlled at the time prior to arrival at the coke plant,
so that a content of particles having a diameter of 6 mm or more in the individual brand of coal or caking additive, the content being determined from a Hardgrove grindability index HGI of the individual brand of coal or caking additive using Expression (1) below, is achieved:
Content (mass %) of particles having a diameter of 6 mm or more≦30+0.5×(HGI−60)  (1),

the permeation distance being measured by a method including the following steps (A) to (D):
(A) crushing the individual brand of coal or caking additive until a content of particles having a diameter of 2 mm or less reaches 100% by mass and then packing a vessel with the individual brand of coal or caking additive that has been crushed at a bulk density of 0.8 g/cm 3 and at a thickness of 10 mm to prepare a sample;
(B) arranging glass beads having a diameter of 2 mm on the sample at a thickness of the permeation distance or more;
(C) while applying a load of 50 kPa to an upper portion of the glass beads, performing heating in an inert gas atmosphere from room temperature to 550° C. at a heating rate of 3° C./min; and
(D) measuring a permeation distance of the softened sample that has permeated a layer composed of the glass beads.

3. A method for preparing coal for coke making, in which an individual brand of coal or caking additive is prepared at a time prior to arrival at a coke plant, the individual brand of coal or caking additive being used alone or in mixture with another coal as a raw material for coke making,
wherein, on the basis of a relationship between a critical permeation distance and a Gieseler maximum fluidity, the relationship being obtained from permeation distances and values of Gieseler maximum fluidity of one or more brands of coal or caking additive,
when a permeation distance of the individual brand of coal or caking additive is larger than or equal to a critical permeation distance calculated from a Gieseler maximum fluidity of the individual brand of coal or caking additive on the basis of the relationship between the critical permeation distance and the Gieseler maximum fluidity, a size of particles of the individual brand of coal or caking additive is controlled at the time prior to arrival at the coke plant so that a content of particles having a diameter of 6 mm or more in the individual brand of coal or caking additive reaches 30% by mass or less.

4. A method for preparing coal for coke making, in which an individual brand of coal or caking additive is prepared at a time prior to arrival at a coke plant, the individual brand of coal or caking additive being used alone or in mixture with another coal as a raw material for coke making,
wherein, on the basis of a relationship between a critical permeation distance and a Gieseler maximum fluidity, the relationship being obtained from permeation distances and values of Gieseler maximum fluidity of one or more brands of coal or caking additive,
when a permeation distance of the individual brand of coal or caking additive is larger than or equal to a critical permeation distance calculated from a Gieseler maximum fluidity of the individual brand of coal or caking additive on the basis of the relationship between the critical permeation distance and the Gieseler maximum fluidity, a size of particles of the individual brand of coal or caking additive is controlled at the time prior to arrival at the coke plant,
so that a content of particles having a diameter of 6 mm or more in the individual brand of coal or caking additive, the content being determined from a Hardgrove grindability index HGI of the individual brand of coal or caking additive using Expression (1) below, is achieved:
Content (mass %) of particles having a diameter of 6 mm or more≦30+0.5×(HGI−60)  (1).

5. The method for preparing coal for coke making according to claim 3 , wherein the critical permeation distance is calculated using Expression (2) below:
Critical permeation distance=1.3× a ×log MF c   (2)

where “a” represents a constant 0.7 to 1.0 times a coefficient of log MF in a regression line crossing an origin point, the regression line being obtained using permeation distances and values of log MF of one or more coals that fall within a range of common logarithm of Gieseler maximum fluidity log MF<2.5, and
MFc represents a Gieseler maximum fluidity (ddpm) of the coal or caking additive to be prepared.

6. The method for preparing coal for coke making according to claim 4 , wherein the critical permeation distance is calculated using Expression (2) below:
Critical permeation distance=1.3× a ×log MF c   (2)

where “a” represents a constant 0.7 to 1.0 times a coefficient of log MF in a regression line crossing an origin point, the regression line being obtained using permeation distances and values of log MF of one or more coals that fall within a range of common logarithm of Gieseler maximum fluidity log MF<2.5, and
MFc represents a Gieseler maximum fluidity (ddpm) of the coal or caking additive to be prepared.

7. The method for preparing coal for coke making according to claim 5 , wherein a represents a constant 0.7 to 1.0 times a coefficient of log MF in a regression line crossing an origin point, the regression line being obtained using permeation distances and values of common logarithm of Gieseler maximum fluidity log MF of one or more coals that fall within a range of 1.75<log MF<2.50.

8. The method for preparing coal for coke making according to claim 6 , wherein a represents a constant 0.7 to 1.0 times a coefficient of log MF in a regression line crossing an origin point, the regression line being obtained using permeation distances and values of common logarithm of Gieseler maximum f

Assignees

• Jfe Steel Corp

Inventors

• Dohi Yusuke
• Shimoyama Izumi
• Fukada Kiyoshi
• Sumi Hiroyuki

Classifications

• G01N11/04

  through a restricted passage, e.g. tube, aperture · CPC title

• C10L5/04

  Raw material {of mineral origin} to be used; Pretreatment thereof {(pretreatment of fuels of non-mineral origin C10L5/40)} · CPC title

• C10L9/10

  by using additives · CPC title

• C10B57/04 Primary

  using charges of special composition · CPC title

• C10L5/08 Primary

  without the aid of extraneous binders · CPC title