Predicting NO x emissions

• US 8,244,505 B2
• Filed: 11/05/2009
• Issued: 08/14/2012
• Est. Priority Date: 11/05/2009
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Headley, Christopher Damien, Noel, Brian Stephen
• Primary Examiner(s): Patel, Shambhavi
• Application Number:
  US12/612,897
• Publication Number:
  US 20110106506A1
• Time in Patent Office: 1,013 Days
• Field of Search: 703/1, 703/6, 703/12, 602/87
• US Class Current: 703/2
• CPC Class Codes: F23N 2223/10 Correlation
• CPC Class Codes: F23N 2223/40 Simulation
• CPC Class Codes: F23N 2227/20 Calibrating devices
• CPC Class Codes: F23N 2900/05003 Measuring NOx content in flue gas
• CPC Class Codes: F23N 5/006 the detector being sensitive to oxygen

Abstract

A method of predicting a nitrogen oxide (NO_x) emission rate of a non-continuous, natural gas-fired boiler is presented. The method includes: calculating a correlation of the NO_x emission rate to a measured fuel flow rate and a sampled oxygen (O₂) concentration based on a plurality of sampled NO_x emission concentrations, measured fuel flow rates, and sampled (O₂) concentrations during operation of the non-continuous, natural gas-fired boiler using a computing device; calculating a predicted NO_x emission rate based on the correlation with the measured fuel flow rate and the sampled O₂ concentration using the computing device; and providing the predicted NO_x emission rate for use by a user.

Claims

1. A method for predicting a nitrogen oxide (NO_x) emission rate of a non-continuous, natural gas-fired boiler, the method comprising:

calculating a plurality of correlations for the NO_x emission rate of the non-continuous, natural gas-fired boiler relative to a plurality of measured fuel flow rates and a plurality of oxygen (O₂) concentrations using a computing device,

wherein the plurality of correlations are based on a plurality of sampled NO_x emission concentrations, sampled fuel flow rates, and sampled O₂ concentrations obtained during operation of the non-continuous, natural gas-fired boiler, each sampled fuel flow rate being sampled across a range of O₂ concentrations;

calculating a predicted NO_x emission rate of the non-continuous, natural gas-fired boiler at a first fuel flow rate and a first O₂ concentration based on the plurality of correlations,

wherein the calculating of the predicted NO_x emission rate includes comparing the first fuel flow rate to the plurality of measured fuel flow rates and comparing the first O₂ concentration to the plurality of O₂ concentrations to determine a related correlation for the first fuel flow rate and the first O₂ concentration relative to the NO_x emission rate; and

providing the predicted NO_x emission rate for use by a user.

2. The method of claim 1, wherein the calculating of the plurality of correlations includes sampling flue gas from the non-continuous, natural gas-fired boiler during operation at a given fuel flow rate while the O₂ concentration is adjusted across a range of O₂ concentrations.

3. The method of claim 1, additionally comprising periodically recalculating the correlation using the computerized device.

4. The method of claim 1, wherein the calculating of the predicted NO_x emission rate comprises:

obtaining a fuel flow rate and a corresponding O₂ concentration of the non-continuous, natural gas-fired boiler during operation;

correlating the obtained fuel flow rate and corresponding obtained O₂ concentration with the correlation to arrive at the measured fuel flow rate and the sampled O₂ concentration using the computerized device; and

calculating the predicted NO_x emission rate based on the correlation with the measured fuel flow rate and the corresponding sampled O₂ concentration.

5. A predictive monitoring system for a nitrogen oxide (NO_x) emission rate comprising:

at least one device including;

a first calculator for calculating a plurality of correlations for the NO_x emission rate of a non-continuous, natural gas-fired boiler relative to a plurality of measured fuel flow rates and a plurality of oxygen (O₂) concentrations,

wherein the plurality of correlations are based on a plurality of sampled NO_x emission concentrations, sampled fuel flow rates, and sampled O₂ concentrations obtained during operation of the non-continuous, natural gas-fired boiler, each sampled fuel flow rate being sampled across a range of O₂ concentrations; and

a second calculator for calculating a predicted NO_x emission rate of the non-continuous, natural gas-fired boiler at a first fuel flow rate and a first O₂ concentration based on the plurality of correlations,

wherein the calculating of the predicted NO_x emission rate includes comparing the first fuel flow rate to the plurality of measured fuel flow rates and comparing the first O₂ concentration to the plurality of O₂ concentrations to determine a related correlation for the first fuel flow rate and the first O₂ concentration relative to the NO_x emission rate.

6. The predictive monitoring system of claim 5, wherein the predictor comprises:

a correlator for correlating an obtained fuel flow rate and corresponding obtained O₂ concentration with the correlation to arrive at the measured fuel flow rate and the corresponding sampled O₂ concentration.

7. The predictive monitoring system of claim 5, wherein the monitoring system is maintained by:

calibrating a non-continuous, natural gas-fired boiler during operation;

calibrating the predictive monitoring system;

recording data related to either of the natural gas-fired boiler or the predictive monitoring system during calibration; and

reporting the data related to either of the natural gas-fired boiler or the predictive monitoring system resulting from calibration.

8. The predictive monitoring system of claim 7, wherein the calibrating comprises calibrating components of the monitoring system selected from the group consisting of:

an oxygen analyzer, a computer system, and a natural gas fuel meter.

9. The predictive monitoring system of claim 7, wherein the data is selected from the group consisting of:

a NO_x emission concentration, fuel flow rate, flue gas oxygen concentration, downtime of the predictive monitoring system, an audit result, a certification report for the predictive monitoring system, a natural gas certification for the predictive monitoring system, a calibration result, and a semiannual report.

10. The predictive monitoring system of claim 5 additionally comprising a user interface for reporting the predicted NO_x emission rate.

11. A computer program comprising program code embodied in at least one non-transitory computer-readable medium, which when executed, enables a computer system to implement a method of predicting a nitrogen oxide (NO_x) emission rate of a non-continuous, natural gas-fired boiler, the method comprising:

calculating a plurality of correlations for the NO_x emission rate of the non-continuous, natural gas-fired boiler relative to a plurality of measured fuel flow rates and a plurality of oxygen (O₂) concentrations,

wherein the plurality of correlations are based on a plurality of sampled NO_x emission concentrations, sampled fuel flow rates, and sampled O₂ concentrations obtained during operation of the non-continuous, natural gas-fired boiler using a computing device, each sampled fuel flow rate being sampled across a range of O₂ concentrations;

calculating a predicted NO_x emission rate of the non-continuous, natural gas-fired boiler at a first fuel flow rate and a first O₂ concentration based on the plurality of correlations,

wherein calculating of the predicted NO_x emission rate includes comparing the first fuel flow rate to the plurality of measured fuel flow rates and comparing the first O₂ concentration to the plurality of O₂ concentrations to determine a related correlation for the first fuel flow rate and the first O₂ concentration relative to the NO_x emission rate; and

providing the predicted NO_x emission rate for use by a user.

12. The computer program of claim 11, wherein the calculating of the plurality of correlations includes sampling flue gas from the non-continuous, natural gas-fired boiler during operation at a given fuel flow rate while the O₂ concentration is adjusted across a range of O₂ concentrations.

13. The computer program of claim 11, additionally comprising periodically recalculating the correlation using the computerized device.

14. The computer program of claim 11, wherein the calculating of the predicted NO_x emission rate comprises:

obtaining a fuel flow rate and a corresponding O₂ concentration of the non-continuous, natural gas-fired boiler during operation;

correlating the obtained fuel flow rate and corresponding obtained O₂ concentration with the correlation to arrive at the measured fuel flow rate and the sampled O₂ concentration using the computerized device; and

calculating the predicted NO_x emission rate based on the correlation with the measured fuel flow rate and the corresponding sampled O₂ concentration.