Combustion optimization with inferential sensor

• US 6,622,645 B2
• Filed: 06/15/2001
• Issued: 09/23/2003
• Est. Priority Date: 06/15/2001
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Havlena, Vladimir
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): RINEHART, KENNETH
• Application Number:
  US09/883,167
• Publication Number:
  US 20030000436A1
• Time in Patent Office: 830 Days
• Field of Search: 431/2, 431/12, 110/185, 110/186, 110/188, 110/341, 110/345, 110/346, 110/347, 432/90, 432/91, 432/36, 432/37, 122/4.D, 60/395.5, 60/393
• US Class Current: 110/348
• CPC Class Codes: F23D 1/00 Burners for combustion of pulverulent fuel disposition of burners F23C
• CPC Class Codes: F23N 1/022 using electronic means
• CPC Class Codes: F23N 2005/181 using detectors sensitive to rate of flow of air
• CPC Class Codes: F23N 2223/44 Optimum control
• CPC Class Codes: F23N 2239/02 Solid fuels
• CPC Class Codes: F23N 5/006 the detector being sensitive to oxygen

Abstract

A method and system for combustion of fuel in a boiler in which flue gasses are produced. The boiler includes a source of fuel, a source of air, and a controller for controlling the ratio of the source of air and the source of fuel inputted into the boiler. A sensor is used for measuring the concentration of oxygen in the flue gasses. The controller is adapted to calculate the amount of air entering the boiler based on the amount of oxygen in the flue gasses to thereby adjust the air to fuel ratio to include calculated air input and air input from the source of air. A preferred fuel is pulverized coal. The method and system provide for the air to fuel ratio to be adjusted to optimize efficiency as well as to minimize NO_x production.

Claims

1. A method of controlling combustion of fuel in a boiler in which flue gasses are produced, comprising the steps of:

providing a source of fuel;

providing a source of air;

providing a controller for controlling the ratio of air to fuel fed into said boiler;

measuring the oxygen content in the flue gasses;

calculating the total amount of air entering said boiler based on the amount of oxygen in the flue gasses; and

adjusting the air to fuel ratio by use of a controller adapted to calculate the total amount of air entering said boiler based on the amount of oxygen measured in the flue gasses to control the air to fuel ratio to include calculated total air input and measured air input from said source of air to lower the source amount of air to the minimum air to produce the lowest NO_x production during combustion;

whereby the efficiency and NO_x production are improved.

2. The method of claim 1, wherein the air to fuel ratio is adjusted to optimize efficiency.

3. The method of claim 1, wherein the air to fuel ratio is adjusted to minimize NO_x production.

4. The method of claim 1, wherein said fuel is pulverized coal.

5. A system for combustion of fuel in a boiler in which flue gasses are produced, comprising:

a source of fuel for combustion in said boiler;

a source of air for combustion with said fuel in said boiler;

a controller for controlling the ratio of said source of air and said source of fuel inputted into said boiler; and

a sensor for measuring the production of oxygen in the flue gasses;

said controller being adapted to calculate the total amount of air entering said boiler based on the amount of oxygen measured in the flue gasses to control the air to fuel ratio to include calculated total air input and air input from said source of air, said controller being adapted to control said source of air for combustion to lower the source amount of air to the minimum air to produce the lowest NO_x production during combustion.

6. The system of claim 5 wherein said fuel is pulverized coal.

7. The system of claim 5 wherein the air to fuel ratio is adjusted to optimize efficiency.

8. The system of claim 5 wherein the air to fuel ratio is adjusted to minimize NO_x production.

9. A system for combustion of fuel in a boiler in which flue gasses are produced, comprising:

fuel source means for providing an input of fuel to said boiler for combustion;

air source means for providing an input of air to said boiler for combustion with said fuel;

controller means for controlling the ratio of said input of air and said input of fuel; and

sensor means for measuring the production of oxygen in said flue gasses;

said controller means being adapted to calculate the amount of air entering said boiler based on the amount of oxygen measured in the flue gasses to control the air to fuel ratio to include calculated total air input and air input from said source of air;

sensor means for measuring the production of oxygen in the flue gasses;

said controller means being adapted to calculate the total amount of air entering said boiler based on the amount of oxygen measured in the flue gasses to control the air to fuel ratio to include calculated total air input and air input from said source of air, said controller means being adapted to control said source of air for combustion to lower the source amount of air to the minimum air to produce the lowest NO_x production during combustion.

10. The system of claim 9 wherein said fuel is pulverized coal.

11. The system of claim 9 wherein the air to fuel ratio is adjusted to optimize efficiency.

12. The system of claim 9 wherein the air to fuel ratio is adjusted to minimize NO_x production.