Methods and systems to increase efficiency and reduce fouling in coal-fired power plants

• US 20080105175A1
• Filed: 11/02/2006
• Published: 05/08/2008
• Est. Priority Date: 11/02/2006
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Payne, Roy, Booth, Michael, Draxton, Dean
• Granted Patent: US 7,865,271 B2
• Time in Patent Office: Days
• US Class Current: 110/185
• CPC Class Codes: F23C 5/32 to obtain rotating flames, i.e. flames moving helically or spirally
• CPC Class Codes: F23C 7/02 Disposition of air supply not passing through burner to obtain a cyclonic tapering flame when burning pulverulent fuel F23C5/32
• CPC Class Codes: F23J 9/00 Preventing premature solidification of molten combustion residues
• CPC Class Codes: F23L 9/04 by discharging the air beyond the fire, i.e. nearer the smoke outlet
• CPC Class Codes: F23N 2241/10 Generating vapour
• CPC Class Codes: F23N 3/002 using electronic means F23N3/02 - F23N3/08 take precedence
• CPC Class Codes: F23N 5/006 the detector being sensitive to oxygen
• CPC Class Codes: F23N 5/022 using electronic means F23N5/04 - F23N5/14 take precedence

Abstract

A system for reducing fouling and improving efficiency in a coal-fired power plant that may include: 1) an analyzer grid, the analyzer grid including a plurality of sensors that measure gas characteristics through an approximate cross section of a flow through a boiler of the coal-fired power plant; 2) a plurality of air injectors with enhanced controllability; 3) means for analyzing the measurements of the gas characteristics; and 4) means for controlling the air injectors with enhanced controllability. The analysis of the measurements of the gas characteristics may include analyzing the measurements to determine zones of non-homogeneous flow.

Claims

1. A system for reducing fouling and improving efficiency in a coal-fired power plant, comprising:

an analyzer grid, the analyzer grid comprising a plurality of sensors that measure gas characteristics through an approximate cross-section of a flow through a boiler of the coal-fired power plant;

a plurality of air injectors with enhanced controllability;

means for analyzing the measurements of the gas characteristics; and

means for controlling the air injectors with enhanced controllability.

2. The system of claim 1, wherein the analysis of the measurements of the gas characteristics comprises analyzing the measurements to determine zones of non-homogeneous flow.

3. The system of claim 2, further comprising means for controlling the air injectors with enhanced controllability so that the zones of non-homogeneous flow are disrupted and a more homogeneous flow throughout the cross-section of flow is realized;

wherein the control of the air injectors with enhanced controllability is based on the analysis of the measurements of gas characteristics.

4. The system of claim 1, wherein the gas characteristics measured by the sensors include at least one of CO, O₂ and temperature levels.

5. The system of claim 1, wherein summing the number of air injectors with enhanced controllability with a number of air injectors without enhanced controllability provides a total number of air injectors;

and

wherein the percentage of the total number of air injectors that are air injectors with enhanced controllability is less than or equal to about 30%.

6. The system of claim 1, wherein summing the number of air injectors with enhanced controllability with a number of air injectors without enhanced controllability provides a total number of air injectors;

and

wherein the percentage of the total number of air injectors that are air injectors with enhanced controllability is less than or equal to about 15%.

7. The system of claim 4, wherein the analysis of the measurements of the gas characteristics comprises analyzing the measurements to determine the extent to which zones within the cross-section of flow have differing CO, O₂, and temperature levels.

8. The system of claim 7, wherein controlling the air injectors with enhanced controllability based on the analysis comprises controlling the air injectors with enhanced controllability such that the differing CO, O₂, and temperature levels between the zones of the cross-section of flow are minimized.

9. The system of claim 1, wherein the air injector with enhanced controllability comprises an air injector with at least one of tilt control, yaw control and air quantity control.

10. The system of claim 1, wherein the coal-fired power plant comprises a tangential coal-fired power plant.

11. The system of claim 1, wherein the analyzer grid is positioned in a convective stage of a boiler and comprises sensors that are substantially evenly spaced over the approximate cross-section of flow.

12. The system of claim 1, wherein the air injectors with enhanced controllability comprise two of the air injectors of two ports within a separated overfire air injector port level, two of the air injectors within a close-coupled overfire air injector port level, and two of the air injectors within a top burner level.

13. The system of claim 1, wherein the air injectors with enhanced controllability comprise two of the air injectors within a separated overfire air injector port level and two of the air injectors within a close-coupled overfire air injector port level.

14. The system of claim 13, wherein the air injectors of the separated overfire air injector port level and the close-coupled overfire air injector port level are located at the corners of a substantially rectangular furnace, and the two air injectors with enhanced controllability within each of the port levels comprise the air injectors positioned on opposite corners of the rectangle.

15. A method for reducing fouling and improving efficiency in an tangential coal-fired power plant, comprising the steps of:

measuring the gas characteristics through an approximate cross-section of a flow through a convective stage;

analyzing the measurements of the gas characteristics to determine zones of non-homogeneous flow; and

controlling a plurality of air injectors with enhanced controllability such that the zones of non-homogeneous flow are disrupted and a more homogeneous flow throughout the cross-section of flow is realized.

16. The method of claim 15, wherein the measuring the gas characteristics through an approximate cross-section of a flow through a convective stage comprises measuring CO, O₂ and temperature levels.

17. The method of claim 16, wherein the step of analyzing the measurements of the gas characteristics to determine zones of non-homogeneous flow comprises analyzing the measurements of gas characteristics to determine the extent to which the zones of non-homogeneous flow within the cross-section of flow have differing CO, O₂, and temperature levels.

18. The method of claim 17, wherein the step of controlling a plurality of air injectors with enhanced controllability such that the zones of non-homogeneous flow are disrupted and a more homogeneous flow throughout the cross-section of flow is realized comprises controlling the air injectors with enhanced controllability such that the differing CO, O₂, and temperature levels in the zones of non-homogeneous flow through the cross-section of flow are minimized.

19. The method of claim 18, wherein the step of controlling the air injectors with enhanced controllability such that the differing CO, O₂, and temperature levels in the zones of the cross-section of flow are minimized comprises the steps of:

making a first adjustment to the air injectors with enhanced controllability;

determining the effect of the first adjustment by analyzing the measurements taken of the gas characteristics taken after the first adjustment; and

making a second adjustment to the air injectors with enhanced controllability based on the effect of the first adjustment.

20. The method of claim 15, wherein the air injector with enhanced controllability comprises an air injector with at least one of tilt control, yaw control, and air quantity control.