Assisted commissioning method for combustion control system

• US 8,602,772 B2
• Filed: 02/20/2008
• Issued: 12/10/2013
• Est. Priority Date: 02/20/2008
• Status: Expired due to Fees

• Current Assignee: UTC Fire & Security Corporation (Rtx Corporation)
• Original Assignee: UTC Fire & Security Corporation (Rtx Corporation)
• Inventors: Fan, Junqiang, Lelic, Muhidin A., Poncia, Guido, Liscinsky, David S., Colket, Meredith B. III, Kennedy, Tom
• Primary Examiner(s): Rinehart, Kenneth
• Assistant Examiner(s): PEREIRO, JORGE ANDRES
• Application Number:
  US12/918,444
• Publication Number:
  US 20110162591A1
• Time in Patent Office: 2,120 Days
• Field of Search: 431/2, 431/6, 431/12, 431/18, 700/274, 700/289
• US Class Current: 431/2
• CPC Class Codes: F23N 5/006 the detector being sensitive to oxygen

Abstract

A method is provided for commissioning a combustion control system for controlling operation of a boiler combustion system. The method includes the step of mapping a plurality of sets of coordinated servo positions for the fuel flow control device and the air flow control device at a plurality of selected firing rate points between a minimum firing rate and a maximum firing rate by using an algorithm and an iterative process to identify the coordinated air and fuel actuator positions instead of a trial and error method.

Claims

1. A method of commissioning a combustion control system for controlling operation of a boiler combustion system having a burner, a fuel flow control device operatively associated with said burner and an air flow control device operatively associated with said burner, the method including mapping a plurality of sets of coordinated servo positions for the fuel flow control device and the air flow control device at a plurality of selected firing rate points between a minimum firing rate and a maximum firing rate, said mapping process comprising, for at least one of said plurality of selected firing rate points, the steps of:

(a) determining one of either the servo position of the fuel flow control device or the servo position of the air flow control associated with the selected firing rate point;

(b) defining an excess oxygen content target value for the selected firing rate point;

(c) repositioning the other of the air flow control device or the fuel flow control device from a previous servo position known to be associated with a measured excess oxygen content value less than the excess oxygen content target value to a current servo position estimated to be associated with an excess oxygen content value greater than the target value;

(d) estimating an optimum servo position for the other of the air flow control device or the fuel flow control device at the selected firing rate by applying an algorithm comprising a function of the previous servo position, the current servo position, a measured value of the excess oxygen content at the previous servo position, a measured value of the excess oxygen content at the current servo position, and said excess oxygen target value; and

(e) repeating steps (c) and (d) until the measured value of the excess oxygen content at the current servo position falls within a preselected range of said excess oxygen target value, thereby defining the optimum servo position for the other of the air flow control device or the fuel flow control device at the selected firing rate; and

(f) saving the optimum servo position of the other of the air flow control device or the fuel flow control device at the selected firing rate and the servo position of the one of the fuel flow control device or the air flow control associated with the selected firing rate at step (a) as a coordinated set associated with the selected firing rate.

2. A method of commissioning a combustion control system as recited in claim 1 further comprising the step of terminating the repetition of steps (c) and (d) after a preselected number of iterations if the measured excess oxygen content does not fall within the preselected range of the excess oxygen content target value and defining the then current servo positions as a coordinated set associated with the selected firing rate.

3. A method of commissioning a combustion control system as recited in claim 2 further comprising the step of:

repeating steps (a) to (f) until a coordinated set of fuel flow control servo position and air flow control servo position has been established at each of a desired plurality of selected firing rate points between the minimum firing rate and the maximum firing rate.

4. A method of commissioning a combustion control system as recited in claim 1, wherein said mapping process comprising, at least one of said plurality of selected firing rate points, the steps of:

(a) determining the fuel flow control servo position for the selected firing rate point;

(b) defining an excess oxygen content target value for the selected firing rate point;

(e) repositioning the air flow control device from a previous air servo position known to be associated with a measured excess oxygen content value less than the excess oxygen content target value to a current air servo position estimated to be associated with an excess oxygen content value greater than the target value;

(d) estimating an optimum air flow control servo position for the selected firing rate by applying an algorithm comprising a function of the previous air servo position, the current air servo position, a measured value of the excess oxygen content at the previous air servo position, a measured value of the excess oxygen content at the current air servo position, and said excess oxygen target value; and

(e) repeating steps (c) and (d) until the measured value of the excess oxygen content at the current air servo position falls within a preselected range of said excess oxygen target value, thereby defining the optimum air flow control servo position at the selected firing rate; and

(f) saving the optimum air flow control servo position at the selected firing rate and the fuel flow control servo position associated with the selected firing rate as a coordinated set associated with the selected firing rate.

5. A method of commissioning a combustion control system as recited in claim 4 wherein the step of estimating an optimum air flow control servo position for the selected firing rate by applying an algorithm comprising a function of the previous air servo position, the current air servo position, a measured value of the excess oxygen content at the previous air servo position, a measured value of the excess oxygen content at the current air servo position, and said excess oxygen target value comprises applying one of the following two formulae:

6. A method of commissioning a combustion control system as recited in claim 5 wherein the first of said formulae is applied when the fuel flow control servo position at the second firing rate is different from the fuel flow control servo position at the first firing rate.

7. A method of commissioning a combustion control system as recited in claim 5 wherein the second of said formulae is applied when the fuel flow control servo position at the second firing rate is not changed.

8. A method of commissioning a combustion control system as recited in claim 1 wherein said mapping process comprises, at least one of said plurality of selected firing rate points, the steps of:

(a) selecting the air flow control servo position for the selected firing rate point;

(b) defining an excess oxygen content target value for the selected air flow servo position;

(c) repositioning the fuel flow control device from a previous fuel servo position known to be associated with a measured excess oxygen content value less than the excess oxygen content target value to a current fuel servo position estimated to be associated with an excess oxygen content value greater than the target value;

(d) estimating an optimum fuel flow control servo position for the selected air servo position by applying an algorithm comprising a function of the previous fuel servo position, the current fuel servo position, a measured value of the excess oxygen content at the previous fuel servo position, a measured value of the excess oxygen content at the current fuel servo position, and said excess oxygen target value; and

(e) repeating steps (c) and (d) until the measured value of the excess oxygen content at the current fuel servo position falls within a preselected range of said excess oxygen target value, thereby defining the optimum fuel flow control servo position at the selected air servo position; and

(f) saving the optimum fuel flow control servo position at the selected air servo position and the selected air servo position servo position associated with the selected firing rate as a coordinated set associated with the selected firing rate.