Method for correcting combustion effluent data when used for input-loss performance monitoring of a power plant

• US 6,714,877 B1
• Filed: 03/01/2002
• Issued: 03/30/2004
• Est. Priority Date: 03/24/1998
• Status: Expired due to Fees

• Current Assignee: Exergetic Systems LLC
• Original Assignee: Exergetic Systems LLC
• Inventors: Lang, Fred D
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Taylor, Victor J.
• Application Number:
  US10/087,879
• Time in Patent Office: 760 Days
• Field of Search: 702/32, 702/22, 700/287, 700/274, 454/192
• US Class Current: 702/32
• CPC Class Codes: F23N 1/002 using electronic means F23N1/04 - F23N1/10 take precedence
• CPC Class Codes: F23N 2223/44 Optimum control
• CPC Class Codes: F23N 5/003 using detectors sensitive to combustion gas properties F23N5/02, F23N5/18 - F23N5/26 take precedence
• CPC Class Codes: F23N 5/203 using electronic means

Abstract

The operation of a fossil-fueled thermal system is quantified by a method for determining correction factors to Choice Operating Parameters, including effluent CO₂ and other parameters, such that combustion stoichiometric consistency and thermodynamic conservations are both achieved. Correcting Choice Operating Parameters is accomplished through multidimensional einimization techniques operating on certain System Effect Parameters. The corrected Choice Operating Parameters may then be supplied to Input/Loss methods as used to monitor and improve system heat rate.

Claims

1. A method for quantifying the operation of a fossil-fired thermal system through accurate knowledge of its system heat rate and other thermal performance parameters when its fuel chemistry, heating value and fuel flow are determined from Input/Loss methods, the method for quantifying the operation comprising the steps of:

selecting a set of minimization techniques applicable to the thermal system and its fuel,

processing a set of routine inputs and convergence criteria to the minimization techniques,

selecting a set of Choice Operating Parameters and their initial values,

determining a set of scaling factors for the set of Choice Operating Parameters resulting in a set of Choice Operating Parameters which are scaled initial values,

determining a set of System Effect Parameters applicable to the thermal system and its fuel whose functionalities effect the determination of system heat rate,

determining a set of Reference System Effect Parameters which uniquely describe the thermal system and its fuel,

determining an objective function applicable to the thermal system'"'"'s stoichiometric situation, the set of scaled Choice Operating Parameters, the set of System Effect Parameters and the set of Reference System Effect Parameters,

optimizing the set of Choice Operating Parameters using their scaled initial values by employing the set of minimization techniques and the objective function such that convergence criteria is met resulting in a set of final Choice Operating Parameters,

determining a set of correction factors to the set of Choice Operating Parameters using their initial and final values resulting in a set of corrected Choice Operating Parameters, and

reporting the set of corrected Choice Operating Parameters.

2. The method according to claim 1 further comprising the steps of:

determining a fuel chemistry of the fuel being combusted by the thermal system using Input/Loss methods using the set of corrected Choice Operating Parameters and Operating Parameters,

determining a fuel heating value of the system using the fuel chemistry,

determining a Firing Correction base on Operating Parameters,

determining a boiler efficiency of the thermal system independent of fuel flow using the set of corrected Choice Operating Parameters, the fuel chemistry, the fuel heating value, the Firing Correction and Operating Parameters,

determining an energy flow to the working fluid of the thermal system based on the system'"'"'s Operating Parameters,

determining a fuel flow of the fuel being combusted using the energy flow to the working fluid, the fuel heating value, the Firing Correction and the boiler efficiency, and

reporting the fuel flow.

3. The method according to claim 2 farther comprising the steps of:

determining a total effluent flow from the thermal system based on the fuel flow, molecular weights of effluents and fuel, and stoichiometric balances based on the set of corrected Choice Operating Parameters, and

reporting the total effluent flow.

4. The method according to claim 3 further comprising the steps of:

determining a constituent gas concentration in the gaseous effluent found at the system boundary,

determining an emission rate of the constituent gas based on the fuel flow, molecular weights of effluents and fuel, and stoichiometric balances based on the set of corrected Choice Operating Parameters, and

reporting the emission rate of the constituent gas.

5. The method of claim 1, wherein the step of determining a set of scaling factors for the set of Choice Operating Parameters includes additional steps of:

assuming the set of scaling factors are all unity,

determining a set of System Effect Parameters applicable to the thermal system and its fuel whose functionalities effect the determination of system heat rate,

determining a set of Reference System Effect Parameters which uniquely describe the thermal system and its fuel,

determining an objective function applicable to the thermal system'"'"'s stoichiometric situation, the set of scaled Choice Operating Parameters, the set of System Effect Parameters and the set of Reference System Effect Parameters,

optimizing the set of Choice Operating Parameters using their initial values by employing a Simulated Annealing algorithm from the set of minimization techniques and the objective function such that numerical differences between the set of System Effect Parameters and the set a Reference System Effect Parameters met convergence criteria resulting in a set of final Choice Operating Parameters,

finding a smallest final Choice Operating Parameter from the set of final Choice Operating Parameters, and

determining a set of scaling factors based on the smallest final Choice Operating Parameter.

6. The method of claim 1, wherein the step of determining the objective function comprises a step of:

forming an objective function dependent on the Bessel Function.

7. The method of claim 1, wherein the step of determining the objective function comprises a step of:

forming an objective function dependent on trigonometric sine and cosine functions.

8. The method according to claim 2 further comprising the steps of:

determining a power output from the thermal system,

determining a system heat rate using the fuel flow, the fuel heating value, the Firing Correction and the power output from the thermal system, and

reporting the system heat rate.

9. The method according to claim 2 further comprising the steps of:

determining a power output from the thermal system,

determining a system heat rate using the energy flow to the working fluid, the boiler efficiency and the power output from the thermal system, and

reporting the system heat rate.

10. The method of claim 1, wherein the step of selecting a set of minimization techniques applicable to the thermal system and its fuel comprises a step of:

including a BFGS technique.

11. The method of claim 1, wherein the step of selecting a set of minimization techniques applicable to the thermal system and its fuel comprises a step of:

including a Simulated Annealing technique.

12. The method of claim 1, wherein the step of selecting a set of minimization techniques applicable to the thermal system and its fuel comprises a step of:

including a neural network technique.

13. The method of claim 1, wherein the step of selecting a set of minimization techniques applicable to the thermal system and its fuel comprises a step of:

including a Neugents technology.

14. A method for quantifying the operation of a fossil-fired thermal system through accurate knowledge of its system heat rate and other thermal performance parameters when its fuel chemistry, heating value and fuel flow are determined from Input/Loss methods, the method for quantifying the operation comprising the steps of:

selecting a neural network technique applicable to the thermal system and its fuel,

processing a set of routine inputs and convergence criteria to the neural network technique,

selecting a set of Choice Operating Parameters and their initial values,

determining a set of System Effect Parameters applicable to the thermal system and its fuel whose functionalities effect the determination of system heat rate,

optimizing the set of Choice Operating Parameters by employing the neural network technique such that convergence criteria is met resulting in a set of final Choice Operating Parameters,

determining a set of correction factors to the set of Choice Operating Parameters using their initial and final values resulting in a set of corrected Choice Operating Parameters, and

reporting the set of corrected Choice Operating Parameters.

15. The method of claim 14, wherein the step of selecting the neural network technique applicable to the thermal system and its fuel comprises a step of:

including a Neugents technology.

16. The method according to claim 14 further comprising the steps of:

determining a fuel chemistry of the fuel being combusted by the thermal system using Input/Loss methods using the set of corrected Choice Operating Parameters and Operating Parameters,

determining a fuel heating value of the system using the fuel chemistry,

determining a Firing Correction base on Operating Parameters,

determining a boiler efficiency of the thermal system independent of fuel flow using the set of corrected Choice Operating Parameters, the fuel chemistry, the fuel heating value, the Firing Correction and Operating Parameters,

determining an energy flow to the working fluid of the thermal system based on the system'"'"'s Operating Parameters,

determining a fuel flow of the fuel being combusted using the energy flow to the working fluid, the fuel heating value, the Firing Correction and the boiler efficiency, and

reporting the fuel flow.

17. The method according to claim 16 further comprising the steps of:

determining a total effluent flow from the thermal system based on the fuel flow, molecular weights of effluents and fuel, and stoichiometric balances based on the set of corrected Choice Operating Parameters, and

reporting the total effluent flow.

18. The method according to claim 17 further comprising the steps of:

determining a constituent gas concentration in the gaseous effluent found at the system boundary,

determining an emission rate of the constituent gas based on the fuel flow, molecular weights of effluents and fuel, and stoichiometric balances based on the set of corrected Choice Operating Parameters, and

reporting the emission rate of the constituent gas.

19. A method for quantifying the operation of a fossil-fired thermal system by computing the volumetric flow of effluent gases, the method for quantifying the operation comprising the steps of:

determining a fuel flow rate,

determining a stoichiometric balance for the combustion process resulting in stoichiometric terms descriptive of Boiler gases, system air leakage and As-Fired fuel,

determining an average molecular weight of the effluent gases,

determining a molecular weight of the As-Fired fuel,

determining an ideal gas density,

computing the volumetric flow of effluent gases based on the fuel flow rate, results from the stoichiometric balance for the combustion process, the average molecular weight of the effluent gases, the molecular weight of the As-Fired fuel and the ideal gas density, and

reporting the volumetric flow.

20. A method for quantifying the operation of a fossil-fired thermal system by computing the volumetric flow of effluent gases, the method for quantifying the operation comprising the steps of:

determining an energy flow to the working fluid,

determining a set of Operating Parameters required for boiler efficiency,

determining a set of Reference Fuel Characteristics descriptive of a typical fuel including a typical heating value,

determining a stoichiometric balance for the combustion process based on the set of Operating Parameters and the set of Reference Fuel Characteristics resulting in stoichiometric terms descriptive of Boiler gases, system air leakage and As-Fired fuel,

determining an average molecular weight of the effluent gases,

determining a molecular weight of the As-Fired fuel,

determining a boiler efficiency of the thermal system,

determining an ideal gas density,

computing the volumetric flow of effluent gases based on the energy flow to the working fluid, the set of Operating Parameters, the set of Reference Fuel Characteristics, results from the stoichiometric balance for the combustion process, the average molecular weight of the effluent gases, the molecular weight of the As-Fired fuel, the boiler efficiency and the ideal gas density, and

reporting the volumetric flow.