Coal-blended fuel, method for combusting the same, and coal fuel for use in coal-blended fuel

Patent metadata

Field	Value
Publication number	US-9353324-B2
Application number	US-201214345468-A
Country	US
Kind code	B2
Filing date	Oct 12, 2012
Priority date	Oct 13, 2011
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

This mixed coal fuel is obtained by mixing a low-grade coal and residual coal. The residual coal is obtained by separating, through evaporation, a solvent from concentrated solids left over when a solution portion, which contains soluble coal components in solvent, is separated from a slurry obtained by mixing and heating coal and a solvent. Furthermore, the ratio (base/acid) of basic components to acidic components contained in ash of the residual coal is lower than that of the low-grade coal.

First claim

The invention claimed is:

1. A coal-blended fuel comprising, in blended form:
a low-grade coal which is a brown coal or subbituminous coal; and
a residual coal,
wherein the coal-blended fuel is in blended form prior to any crushing of the low-grade coal and the residual coal,
wherein the residual coal is obtained by a process comprising:
mixing and heating a feed coal and a solvent to form a slurry;
separating a solution fraction comprising solvent-soluble coal components from the slurry to obtain a solid-concentrated solution; and
separating the solvent from the solid-concentrated solution by evaporation to obtain the residual coal, wherein:
the residual coal has a lower ratio of basic components to acidic components contained in ash than the low-grade coal,
the low-grade coal has a moisture content of 20% to 35% by weight;
the low-grade coal has an ash content of 8% by weight or less;
the residual coal has a moisture content of 8% by weight or less; and
the residual coal has an ash content of 17% to 25% by weight.

2. The coal-blended fuel of claim 1 , wherein the blend ratio of the residual coal is 25% to 50% by weight.

3. The coal-blended fuel of claim 1 , wherein the feed coal used to produce the residual coal is a bituminous coal.

4. A method for combusting a coal-blended fuel comprising:
supplying the coal-blended fuel of claim 1 to a boiler; and
combusting the coal-blended fuel.

5. The method of claim 4 , further comprising:
crushing the coal-blended fuel to form a pulverized coal prior to supplying the fuel to the boiler;
injecting the pulverized coal and air into the boiler; and
combusting the pulverized coal and air in the boiler.

6. A method for producing a coal-blended fuel according to claim 1 , the method comprising:
mixing and heating a feed coal and a solvent to form a slurry;
separating a solution fraction comprising solvent-soluble coal components from the slurry to obtain a solid-concentrated solution;
separating the solvent from the solid-concentrated solution by evaporation to obtain a residual coal; and
mixing the residual coal with a low grade coal which is a brown coal or a subbituminous coal, wherein:
the residual coal has a lower ratio of basic components to acidic components contained in ash than the low-grade coal,
the low-grade coal has a moisture content of 20% to 35% by weight;
the low-grade coal has an ash content of 8% by weight or less;
the residual coal has a moisture content of 8% by weight or less; and
the residual coal has an ash content of 17% to 25% by weight.

7. The method of claim 6 , wherein the blend ratio of the residual coal is 25% to 50% by weight.

8. The method of claim 6 , wherein the feed coal used to produce the residual coal is a bituminous coal.

Assignees

• Kobe Steel Ltd
• Kobe Steel Ltd

Inventors

• Tada Toshiya
• Takubo Yoji

Classifications

• C10L1/326 Primary

  Coal-water suspensions · CPC title

• Y02E50/30

  Fuel from waste, e.g. synthetic alcohol or diesel · CPC title

• C10L9/10

  by using additives · CPC title

• F23D1/005

  burning a mixture of pulverulent fuel delivered as a slurry, i.e. comprising a carrying liquid · CPC title

• C10L5/04 Primary

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