Inhibition of reflective ash build-up in coal-fired furnaces

• US 20020088170A1
• Filed: 01/11/2001
• Published: 07/11/2002
• Est. Priority Date: 01/11/2001
• Status: Active Grant

• Current Assignee: Benentech Incorporated
• Original Assignee: Benetech, Inc. (Benetech Holdings LLC)
• Inventors: Sanyal, Anupam
• Granted Patent: US 6,613,110 B2
• Time in Patent Office: Days
• US Class Current: 44/627
• CPC Class Codes: C10L 10/04 for minimising corrosion or incrustation
• CPC Class Codes: C10L 5/366 Powders
• CPC Class Codes: C10L 9/10 by using additives

Abstract

A method, for inhibiting accumulation of light-colored ash on the walls of a furnace in which coal containing high levels of (coal-bound) calcium is burned, comprises adding an iron compound to the coal prior to burning the coal, burning the coal, and producing calcium ferrite, thereby improving heat transfer in furnaces and resultant plant efficiency without adverse environmental consequences.

Claims

1. A method for inhibiting accumulation of reflective ash on surfaces in a furnace in which calcium-containing coal is burned, comprising:

(a) adding to the coal enough of a fluxing agent-free composition comprising an iron compound to produce treated coal that is free of added fluxing agent and contains an effective amount of the iron compound; and

(b) burning the treated coal.

2. A method as set forth in claim 1 wherein the iron compound is iron oxide.

3. A method as set forth in claim 2 wherein the iron oxide is ferric oxide.

4. A method as set forth in claim 1 wherein calcium ferrite is produced when the treated coal is burned.

5. A method as set forth in claim 4 wherein the iron compound is iron oxide.

6. A method as set forth in claim 5 wherein the iron oxide is ferric oxide.

7. A method as set forth in claim 4 wherein burning the coal forms calcium oxide, which then reacts with the iron compound to form calcium ferrite.

8. A method as set forth in claim 5 wherein burning the coal forms calcium oxide, which then reacts with the iron compound to form calcium ferrite.

9. A method as set forth in claim 6 wherein burning the coal forms calcium oxide, which then reacts with the iron compound to form calcium ferrite.

10. A method as set forth in claim 14 comprising the steps of.

(a) adding an effective amount of an iron compound to the coal to produce treated coal free of added fluxing agent;

(b) grinding the treated coal to produce ground, treated coal free of added fluxing agent;

(c) introducing the ground, treated coal free of added fluxing agent into a furnace; and

(d) burning the ground, treated coal free of added fluxing agent in the furnace.

11. A method as set forth in claim 3 wherein the ferric oxide is added in an amount of from about 0.25% to about 0.75% based on the weight of the coal.

12. A method as set forth in claim 6 wherein the ferric oxide is added in an amount of from about 0.25% to about 0.75% based on the weight of the coal.

13. A method as set forth in claim 9 wherein the ferric oxide is added in an amount of from about 0.1% to about 0.75% based on the weight of the coal.

14. A method as set forth in claim 1 wherein the method consists essentially of:

(a) adding to the coal enough of a fluxing agent-free composition comprising an iron compound to produce treated coal that is free of added fluxing agent and contains an effective amount of the iron compound; and

(b) burning the treated coal.

15. A method as set forth in claim 14 wherein the fluxing agent-free composition consists essentially of ferric oxide.

17. A method as set forth in claim 16 wherein the iron compound is iron oxide.

18. A method as set forth in claim 17 wherein the iron oxide is ferric oxide.

19. A method as set forth in claim 16, comprising the steps of:

(a) adding an effective amount of an iron compound to the coal to produce treated coal;

(b) grinding the treated coal to produce ground, treated coal;

(c) introducing the ground, treated coal into a furnace; and

(d) burning the ground, treated coal in the furnace, producing ash of increased melting point.

20. A method as set forth in claim 19, consisting essentially of the steps of:

(a) adding to the coal enough of a composition consisting essentially of ferric oxide to produce treated coal containing an effective amount of ferric oxide;

(b) grinding the treated coal to produce ground, treated coal;

(c) introducing the ground, treated coal into a furnace; and

(d) burning the ground, treated coal in the furnace, producing ash of increased melting point.

16. A method for increasing the melting point of ash produced during the burning of calcium-containing coal, comprising:

(a) adding an effective amount of an iron compound to the coal to produce treated coal; and

(b) burning the treated coal, producing ash of increased melting point.