Method for preparing blast furnace blow-in coal

Patent metadata

Field	Value
Publication number	US-9605225-B2
Application number	US-201314412785-A
Country	US
Kind code	B2
Filing date	Sep 13, 2013
Priority date	Oct 9, 2012
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

Provided is a method for preparing blast furnace blow-in coal that can, at a low cost, obtain blast furnace blow-in coal that suppresses occlusion by blast furnace blow-in ash or accretion of blast furnace blow-in ash in a pathway leading to a tuyere of a blast furnace main body, while suppressing a decrease in the amount of heat release. The method includes selecting first and second coal types satisfying conditions (S 2 , S 3 ), on the basis of the CaO content in the ash when the oxides of Al, Si, Ca, and Mg in the ash is 100 wt % and the Al 2 O 3 content in the ash is 20 wt %, deriving the mixing ratio of the first and second coal types that results in the CaO content in the ash of the mixed coal being at least 40 wt % (S 4 ), and mixing the first and second coal types (S 5 ) at the mixing ratio.

First claim

The invention claimed is:

1. A method for preparing blast furnace blow-in coal, the method comprising:
a first step of analyzing a moisture content of run-of-mine coal, ash of the coal, and weight percentages of Al, Si, Ca and Mg in the ash;
a second step of selecting, based on data obtained by analysis, a first coal type, of which the moisture content of the run-of-mine coal is greater than or equal to 15% by weight, and, when a total of Al, Si, Ca and Mg oxides in the ash is taken as 100% by weight, an Al 2 O 3 content is 20% by weight ±5% by weight, a CaO content is greater than or equal to 20% by weight and less than or equal to 40% by weight, and an MgO content is less than or equal to 10% by weight;
a third step of selecting, based on data obtained by analysis, a second coal type, of which, when the total of Al, Si, Ca and Mg oxides in the ash is taken as 100% by weight, the Al 2 O 3 content is 20% by weight ±5% by weight and is adapted to be 20% by weight upon mixing with the first coal type, the CaO content is greater than or equal to 40% by weight, and the MgO content is less than or equal to 10% by weight;
a fourth step of deriving a mixing ratio of the first coal type and the second coal type that results in the CaO content being greater than or equal to 40% by weight in the ash of mixed coal resulting from mixing the first coal type and the second coal type, based on the CaO content in the ash of the first coal type when the total weight of Al, Si, Ca and Mg oxides in that ash is taken as 100% by weight and the Al 2 O 3 content in that ash is taken as 20% by weight, and based on the CaO content in the ash of the second coal type when the total weight of Al, Si, Ca and Mg oxides in that ash is taken as 100% by weight and the Al 2 O 3 content in that ash is taken as 20% by weight; and
a fifth step of mixing the first coal type and the second coal type in the mixing ratio.

2. The method for preparing blast furnace blow-in coal according to claim 1 , further comprising
a sixth step of pyrolyzing the mixed coal resulting from mixing the first coal type and the second coal type.

3. The method for preparing blast furnace blow-in coal according to claim 1 , further comprising
a pretreatment step of separately pyrolyzing the first coal type and the second coal type, which is performed before the fifth step; and a seventh step of molding the mixed coal, which is performed after the fifth step.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Nakagawa Keiichi
• Omoto Setsuo
• Sakaguchi Masakazu
• Hamada Tsutomu

Classifications

• C10L2290/60

  Measuring or analysing fractions, components or impurities or process conditions during preparation or upgrading of a fuel · CPC title

• C10L2290/02

  Combustion or pyrolysis · CPC title

• C21B5/007

  Conditions of the cokes or characterised by the cokes used · CPC title

• C10B53/04

  of powdered coal · CPC title

• C21B5/003

  Injection of pulverulent coal · CPC title