Input/Loss Method using the genetics of fossil fuels for determining fuel chemistry, calorific value and performance of a fossil-fired power plant

• US 7,328,132 B2
• Filed: 03/17/2006
• Issued: 02/05/2008
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: Exergetic Systems LLC
• Original Assignee: Exergetic Systems LLC
• Inventors: Lang, Fred D.
• Primary Examiner(s): Barbee; Manuel L.
• Application Number:
  US11/378,999
• Publication Number:
  US 20070219730A1
• Time in Patent Office: 690 Days
• Field of Search: None
• US Class Current: 702/183
• CPC Class Codes: F23N 2221/08 Preheating the air
• CPC Class Codes: F23N 2223/08 Microprocessor; Microcomputer
• CPC Class Codes: F23N 2223/10 Correlation
• CPC Class Codes: F23N 2223/40 Simulation
• CPC Class Codes: F23N 2225/10 stack temperature
• CPC Class Codes: F23N 2225/22 heat losses
• CPC Class Codes: F23N 2239/02 Solid fuels
• CPC Class Codes: F23N 2239/04 Gaseous fuels
• CPC Class Codes: F23N 2239/06 Liquid fuels
• CPC Class Codes: F23N 2241/10 Generating vapour
• CPC Class Codes: F23N 2241/18 Incinerating apparatus
• CPC Class Codes: F23N 2241/20 Gas turbines
• 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 5/006 the detector being sensitive to oxygen
• CPC Class Codes: G01N 33/222 Solid fuels, e.g. coal
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

This invention relates to any fossil fueled thermal system, and especially relates to large commercial steam generators used in power plants, and, more particularly, to a method and apparatus for determining fuel chemistry in essentially real time based on effluents resulting from combustion, associated stoichiometrics, and the genetics of the fossil fuel. Knowing the system'"'"'s fuel chemistry, the fuel calorific value, the fuel flow and the thermal performance associated with the thermal system may then be determined in essentially real time.

Claims

1. A method for quantifying the operation of a thermal system burning a fossil fuel having a heat exchanger/combustion region producing combustion products, the method comprising the steps of:

operating a computer programmed with a mathematical description of the thermal system based on a closed-form solution, resulting in a programmed computer;

obtaining a set of Choice Operating Parameters selected from the group consisting of;

a Stack CO₂, a Boiler CO₂, a Stack H₂O, a Boiler H₂O, an Air Pre-Heater Leakage Factor, a concentration of O₂ in the combustion air local to the thermal system, an indicated plant limestone flow, a Stack O₂, a Boiler O₂, and a relative humidity of the ambient air local to the thermal system;

obtaining a fuel ash concentration selected from the group consisting of;

a constant value of fuel ash, a predictable value of fuel ash, a measured value of fuel ash determined from a fuel ash instrument and a value of fuel ash determined from an explicit solution, as an obtained fuel ash concentration; and

operating the programmed computer to obtain a complete As-Fired fuel chemistry, including fuel water and fuel ash, based on the mathematical description of the thermal system, the set of Choice Operating Parameters, and the obtained fuel ash concentration.

7. The method of claims 1, 2, 3, 4, 5 or 6, wherein the thermal system comprises a thermal system selected from the group consisting of:

a coal-burning power plant, a lignite-burning power plant, an oil-burning power plant, a gas-fired power plant, a biomass combustor, a fluidized bed combustor, a conventional electric power plant, a steam generator, a package boiler, a combustion turbine, a combustion turbine with a heat recovery boiler, a power plant burning Irish peat, and a Recovery Boiler used in the pulp and paper industry.

8. The method of claims 1, 2, 3, 4, 5 or 6, wherein the step of operating the programmed computer to obtain the complete As-Fired fuel chemistry includes the steps of

operating the programmed computer to obtain a fuel chemistry including at least one fuel constituent selected from the group consisting of:

weight percent carbon, weight percent hydrogen and weight percent oxygen of the fuel, and

calculating a fuel calorific value based on the fuel chemistry in units of kJ/kg, the step of calculating including a step of forming products of numerical coefficients times the weight percent of the fuel constituent, wherein at least one of the numerical coefficients is selected from the group consisting of from 325 to 358 for weight percent carbon, from 896 to 1454 for weight percent hydrogen, and from −

86 to −

181 for weight percent oxygen and combinations thereof.

9. The method of claims 1, 2, 3, 4, 5 or 6, wherein the step of operating the programmed computer to obtain the complete As-Fired fuel chemistry includes the steps of

operating the programmed computer to obtain a fuel chemistry including at least one fuel constituent selected from the group consisting of:

weight percent carbon, weight percent hydrogen and weight percent oxygen of the fuel, and

calculating a fuel calorific value based on the fuel chemistry in units of Btu per pound-mass, the step of calculating including a step of forming products of numerical coefficients times the weight percent of the fuel constituent, wherein at least one of the numerical coefficients is selected from the group consisting of from 140 to 154 for weight percent carbon, from 385 to 625 for weight percent hydrogen, and from −

37 to −

78 for weight percent oxygen and combinations thereof.

10. The method of claims 1, 2, 3, 4, 5 or 6, wherein the step of obtaining the concentration of O₂ in the combustion air local to the system includes the step of using a concentration of O₂ in the combustion air local to the system obtained from the United States National Aeronautics and Space Administration.

11. The method of claims 1, 3 or 5, wherein the step of operating the computer programmed with the mathematical description of the thermal system, includes the step of

operating the computer programmed with the mathematical description of the thermal system based on one of the Input/Loss methods.

13. The method of claims 1, 3 or 5, wherein the step of operating the computer programmed with the mathematical description of the thermal system, includes the step of

operating the computer programmed with the mathematical description of the thermal system based on matrix solution.

15. The method of claims 1, 2, 3 or 4, including, after the step of operating the programmed computer to obtain the complete As-Fired fuel chemistry, the additional steps of

obtaining a corrected L₁₀ Factor based on the complete As-Fired fuel chemistry;

establishing a reference L₁₀ Factor;

operating the programmed computer to obtain a multidimensional minimization analysis based on minimizing error between the corrected L₁₀ Factor and the reference L₁₀ Factor, such that at least one Choice Operating Parameter of a set of Choice Operating Parameters is corrected, the set of Choice Operating Parameters selected from the group consisting of;

effluent concentration of CO₂, effluent concentration of O₂, the obtained effluent H₂O, the concentration of O₂ in the ambient air entering the thermal system and the Air Pre-Heater Leakage Factor resulting in a set of correction factors; and

operating the programmed computer by applying in subsequent on-line analysis the set of correction factors to the set of Choice Operating Parameters.

16. The method of claims 1, 2, 3 or 4, after the step of operating the programmed computer to obtain the complete As-Fired fuel chemistry, the additional step which comprises

operating the programmed computer to obtain an As-Fired fuel calorific value as a function of the complete As-Fired fuel chemistry.

17. The method of claim 16, after the step of operating the programmed computer to obtain an As-Fired fuel calorific value, the additional steps which comprise

measuring an effluent temperature of the combustion gas,

operating the programmed computer to obtain a boiler efficiency as a function of the complete As-Fired fuel chemistry, the set of Choice Operating Parameters, the As-Fired fuel calorific value and the effluent temperature.

18. The method of claim 16, after the step of operating the programmed computer to obtain the As-Fired fuel calorific value, the additional steps which comprise

obtaining a set of effluent concentrations including at least effluent SO₂, and

operating the programmed computer to obtain individual emission rates based on the As-Fired fuel calorific value and the set of effluent concentrations.

19. The method of claim 17, after the step of operating the programmed computer to obtain the boiler efficiency, the additional steps which comprise

measuring an electrical generation produced from the thermal system,

measuring an energy flow to the working fluid heated by combustion products;

and

operating the programmed computer to obtain a system thermal efficiency as a function of the boiler efficiency, the electrical generation produced, and the energy flow to the working fluid.

20. The method of claim 17, after the step of operating the programmed computer to obtain the boiler efficiency, the additional steps which comprise

measuring an energy flow to the working fluid heated by combustion products, and

operating the programmed computer to obtain an As-Fired fuel flow based on the boiler efficiency, the As-Fired fuel calorific value, and the energy flow to the working fluid.

21. The method of claim 20, after the step of operating the programmed computer to obtain the As-Fired fuel flow, the additional step which comprises

operating the programmed computer to obtain a total effluent flow based on the As-Fired fuel flow.

22. The method of claim 20, after the step of operating the programmed computer to obtain the As-Fired fuel flow, the additional steps which comprise

obtaining a set of effluent concentrations including at least effluent SO₂, and

operating the programmed computer to obtain individual effluent flows based on the set of effluent concentrations and the As-Fired fuel flow.

23. The method of claim 20, including, after the step of operating the programmed computer to obtain the As-Fired fuel flow, the additional steps which comprise

obtaining an indicated plant fuel flow associated with the thermal system;

operating the programmed computer to perform a multidimensional minimization analysis based on minimizing error between the As-Fired fuel flow and the indicated plant fuel flow, such that at least one Choice Operating Parameter of a set of Choice Operating Parameters is corrected, the set of Choice Operating Parameters selected from the group consisting of;

effluent concentration of CO₂, effluent concentration of O₂, the obtained effluent H₂O, the concentration of O₂ in the ambient air entering the thermal system and the Air Pre-Heater Leakage Factor resulting in a set of correction factors; and

operating the programmed computer by applying in subsequent analysis the set of correction factors to the set of Choice Operating Parameters.

24. The method of claim 20, after the step of operating the programmed computer to obtain the As-Fired fuel flow, the additional steps which comprise

obtaining a gas density and a molecular weight of the effluent gas, and

operating the programmed computer to obtain an effluent volumetric flow based on the As-Fired fuel flow, the gas density and the molecular weight of the effluent gas.

35. The method of claims 1, 3 or 5, wherein the step of operating the computer programmed with the mathematical description of the thermal system includes the additional step, of

operating the computer programmed with the mathematical description of the thermal system based on stoichiometric relationships and genetics of the fossil fuel in the form CH_c2O_c3, the reduced value c3 selected from the group consisting of a value from 0.009 to 0.024 for anthracite coal, from 0.025 to 0.054 for semi-anthracite coal, from 0.055 to 0.121 for the coal Ranks of hvAb and hvBb, from 0.122 to 0.170 for sub-bituminous A coal, from 0.171 to 0.183 for Powder River Basin coal, from 0.184 to 0.200 for sub-bituminous B coal, from 0.201 to 0.215 for sub-bituminous C coal, from 0.216 to 0.230 for lignite A, from 0.390 to 0.458 for Greek lignite, and from 0.459 to 0.520 for Irish peat, and combinations thereof.

37. The method of claims 1, 2, 3 or 4, wherein the step of obtaining the set of Choice Operating Parameters includes

obtaining a set of Choice Operating Parameters selected from the group consisting of:

a Stack CO₂, a Boiler CO₂, a Stack H₂O, a Boiler H₂O, an Air Pre-Heater Leakage Factor, a concentration of O₂ in the combustion air local to the thermal system, an indicated plant limestone flow, a Stack O₂, a Boiler O₂, a relative humidity of the ambient air local to the thermal system, and a tube leakage flow rate.

38. The method of claims 1, 2, 3 or 4, after the step of operating the programmed computer to obtain the complete As-Fired fuel chemistry, the additional step comprising

operating the programmed computer to obtain a set of correction factors to be applied to the set of Choice Operating Parameters, the set of Choice Operating Parameters selected from the group consisting of:

effluent concentration of O₂, effluent concentrations of CO₂, the concentration of O₂ in the combustion air local to the system and the Air Pre-Heater Leakage Factor, the set of correction factors selected from the group consisting of;

a set of obtained correction factors, and a set of correction factors based on a multidimensional minimization analysis.

39. The method of claims 1, 2, 3 or 4, wherein the step of operating the programmed computer to obtain the complete As-Fired fuel chemistry, comprises the step of

operating the programmed computer to obtain an Ultimate Analysis of the fuel chemistry based on the mathematical description of the thermal system, the set of Choice Operating Parameters and the obtained fuel ash concentration.

2. A method for quantifying the operation of a thermal system burning a fossil fuel having a heat exchanger/combustion region producing combustion products, the method comprising the steps of:

before on-line operation,

developing a mathematical description of the thermal system based on a closed-form solution;

while operating on-line, the step of operating on-line comprising the steps of

obtaining a set of Choice Operating Parameters selected from the group consisting of;

a Stack CO₂, a Boiler CO₂, a Stack H₂O, a Boiler H₂O, an Air Pre-Heater Leakage Factor, a concentration of O₂ in the combustion air local to the thermal system, an indicated plant limestone flow, a Stack O₂, a Boiler O₂, and a relative humidity of the ambient air local to the thermal system,

obtaining a fuel ash concentration selected from the group consisting of;

a constant value of fuel ash, a predictable value of fuel ash, a measured value of fuel ash determined from a fuel ash instrument and a value of fuel ash determined from an explicit solution, as an obtained fuel ash concentration, and

operating a programmed computer to obtain a complete As-Fired fuel chemistry, including fuel water and fuel ash, based on the mathematical description of the thermal system, the set of Choice Operating Parameters, and the obtained fuel ash concentration.

12. The method of claims 2, 4 or 6, wherein the step of developing the mathematical description of the thermal system, includes the step of

developing the mathematical description of the thermal system based on one of the Input/Loss methods.

14. The method of claims 2, 4 or 6, wherein the step of developing the mathematical description of the thermal system, includes the step of

developing the mathematical description of the thermal system based on matrix solution.

36. The method of claims 2, 4 or 6, wherein the step of developing the mathematical description of the thermal system includes the additional step, of

developing the mathematical description of the thermal system based on stoichiometric relationships and genetics of the fossil fuel in the form CH_c2O_c3, the reduced value c3 selected from the group consisting of a value from 0.009 to 0.024 for anthracite coal, from 0.025 to 0.054 for semi-anthracite coal, from 0.055 to 0.121 for the coal Ranks of hvAb and hvBb, from 0.122 to 0.170 for sub-bituminous A coal, from 0.171 to 0.183 for Powder River Basin coal, from 0.184 to 0.200 for sub-bituminous B coal, from 0.201 to 0.215 for sub-bituminous C coal, from 0.216 to 0.230 for lignite A, from 0.390 to 0.458 for Greek lignite, and from 0.459 to 0.520 for Irish peat, and combinations thereof.

3. A method for quantifying the operation of a thermal system burning a fossil fuel having a heat exchanger/combustion region producing combustion products, the method comprising the steps of:

operating a computer programmed with a mathematical description of the thermal system based on stoichiometric relationships and a genetics of the fossil fuel based on multi-variant analysis, resulting in a programmed computer,

obtaining a set of Choice Operating Parameters selected from the group consisting of;

a Stack CO₂, a Boiler CO₂, a Stack H₂O, a Boiler H₂O, an Air Pre-Heater Leakage Factor, a concentration of O₂ in the combustion air local to the thermal system, an indicated plant limestone flow, a Stack O₂, a Boiler O₂, and a relative humidity of the ambient air local to the thermal system;

obtaining a fuel ash concentration selected from the group consisting of;

a constant value of fuel ash, a predictable value of fuel ash, a measured value of fuel ash determined from a fuel ash instrument and a value of fuel ash determined from an explicit solution, as an obtained fuel ash concentration; and

operating the programmed computer to obtain a complete As-Fired fuel chemistry, including fuel water and fuel ash, based on the mathematical description of the thermal system, the set of Choice Operating Parameters, and the obtained fuel ash concentration.

4. A method for quantifying the operation of a thermal system burning a fossil fuel having a heat exchanger/combustion region producing combustion products, the method comprising the steps of:

before on-line operation,

developing a mathematical description of the thermal system based on combustion stoichiometrics and a genetics of the fossil fuel based on the multi-variant analysis;

while operating on-line, the step of operating on-line comprising the steps of

obtaining a set of Choice Operating Parameters selected from the group consisting of;

a Stack CO₂, a Boiler CO₂, a Stack H₂O, a Boiler H₂O, an Air Pre-Heater Leakage Factor, a concentration of O₂ in the combustion air local to the thermal system, an indicated plant limestone flow, a Stack O₂, a Boiler O₂, and a relative humidity of the ambient air local to the thermal system;

obtaining a fuel ash concentration selected from the group consisting of;

a constant value of fuel ash, a predictable value of fuel ash, a measured value of fuel ash determined from a fuel ash instrument and a value of fuel ash determined from an explicit solution, as an obtained fuel ash concentration; and

operating a programmed computer to obtain a complete As-Fired fuel chemistry, including fuel water and fuel ash, based on the mathematical description of the thermal system, the set of Choice Operating Parameters, and the obtained fuel ash concentration.

5. A method for quantifying the operation of a thermal system burning a fossil fuel having a heat exchanger/combustion region producing combustion products, the method comprising the steps of:

operating a computer programmed with a mathematical description of the thermal system based on stoichiometric relationships and a genetics of the fossil fuel based on the multi-variant analysis, resulting in a programmed computer,

measuring a set of measurable Operating Parameters, including at least effluent concentrations of O₂ and CO₂, these measurements being made at a location downstream of the heat exchanger/combustion region of the thermal system,

obtaining an effluent concentration of H₂O, as an obtained effluent H₂O,

obtaining a fuel ash concentration selected from the group consisting of;

a constant value of fuel ash, a predictable value of fuel ash, a measured value of fuel ash determined from a fuel ash instrument and a value of fuel ash determined from an explicit solution, as an obtained fuel ash concentration,

obtaining a concentration of O₂ in the combustion air local to the system,

obtaining an Air Pre-Heater Leakage Factor, and

operating the programmed computer to obtain a complete As-Fired fuel chemistry, including fuel water and fuel ash, based on the mathematical description of the thermal system, the set of measurable Operating Parameters, the obtained effluent H₂O, the obtained fuel ash concentration, the concentration of O₂ in the combustion air local to the system and the Air Pre-Heater Leakage Factor.

25. The method of claims 5 or 6, after the step of operating the programmed computer to obtain the complete As-Fired fuel chemistry, the additional step comprising of

operating the programmed computer to obtain an As-Fired fuel calorific value as a function of the complete As-Fired fuel chemistry.

26. The method of claim 25, wherein the step of measuring the set of measurable Operating Parameters includes the step of

measuring an effluent temperature;

and wherein the method further includes an additional step, after the step of operating the programmed computer to obtain a complete As-Fired fuel chemistry, of

operating the programmed computer to obtain a boiler efficiency as a function of the complete As-Fired fuel chemistry, the effluent temperature, effluent concentrations and the As-Fired fuel calorific value.

27. The method of claim 25, after the step of operating the programmed computer to obtain the As-Fired fuel calorific value, the additional steps comprising

obtaining a set of effluent concentrations including at least effluent SO₂, and

operating the programmed computer to obtain individual emission rates based on the As-Fired fuel calorific value and the set of effluent concentrations.

28. The method of claim 26, wherein the step of measuring the set of measurable Operating Parameters includes the steps of

measuring an electrical generation produced from the thermal system, and

measuring an energy flow to the working fluid heated by combustion products;

and wherein the method further includes an additional step, after the step of operating the programmed computer to obtain a boiler efficiency, of

operating the programmed computer to obtain a system thermal efficiency as a function of the electrical generation produced, the energy flow to the working fluid and the boiler efficiency.

29. The method of claim 26, wherein the step of measuring the set of measurable Operating Parameters includes the step of

measuring an energy flow to the working fluid heated by combustion products;

and wherein the method further includes an additional step, after the step of operating the programmed computer to obtain a boiler efficiency, of

operating the programmed computer to obtain an As-Fired fuel flow based on the boiler efficiency, the As-Fired fuel calorific value, and the energy flow to the working fluid.

30. The method of claim 29, after the step of operating the programmed computer to obtain the As-Fired fuel flow, an additional step comprising

operating the programmed computer to obtain a total effluent flow based on the As-Fired fuel flow.

31. The method of claim 29, after the step of operating the programmed computer to obtain the As-Fired fuel flow, the additional steps comprising

obtaining a set of effluent concentrations including at least effluent SO₂, and

operating the programmed computer to obtain individual effluent flows based on the set of effluent concentrations and the As-Fired fuel flow.

32. The method of claim 29, including, after the step of operating the programmed computer to obtain the As-Fired fuel flow, the additional steps of

obtaining an indicated plant fuel flow associated with the thermal system;

operating the programmed computer to obtain a multidimensional minimization analysis based on minimizing error between the As-Fired fuel flow and the indicated plant fuel flow, such that at least one Choice Operating Parameter of a set of Choice Operating Parameters is corrected, the set of Choice Operating Parameters selected from the group consisting of;

effluent concentration of CO₂, effluent concentration of O₂, the obtained effluent H₂O, the concentration of O₂ in the ambient air entering the thermal system and the Air Pre-Heater Leakage Factor resulting in a set of correction factors; and

operating the programmed computer by applying in subsequent analysis the set of correction factors to the set of Choice Operating Parameters.

33. The method of claim 29, after the step of operating the programmed computer to obtain the As-Fired fuel flow, the additional steps comprising

obtaining a standard density of the effluent gas,

obtaining an average molecular weight of the effluent gas, and

operating the programmed computer to obtain a total effluent dry volumetric flow based on the As-Fired fuel flow, the standard density and the average molecular weight of the effluent gas.

34. The method of claims 5 or 6, wherein the step of measuring the set of measurable Operating Parameters includes an additional step of

obtaining a set of effluent concentrations, the set of effluent concentrations containing at least one selected from the group consisting of:

CO, SO₂ and NO_X, resulting in a set of pollutant concentrations; and

wherein the step of operating the programmed computer to obtain a complete As-Fired fuel chemistry includes the step of

operating the programmed computer to obtain the complete As-Fired fuel chemistry, including fuel water and fuel ash, based on the mathematical description of the thermal system, the set of measurable Operating Parameters, the obtained effluent H₂O, the obtained fuel ash concentration, the concentration of O₂ in the combustion air local to the system, the Air Pre-Heater Leakage Factor, and the set of effluent pollutant concentrations.

40. The method of claims 5 or 6, wherein the step of operating the programmed computer to obtain the complete As-Fired fuel chemistry, comprises the step of

operating the programmed computer to obtain an Ultimate Analysis of the fuel chemistry based on the mathematical description of the thermal system, said mathematical description based on stoichiometric relationships and genetics of the fossil fuel, the set of measurable Operating Parameters, the obtained effluent H₂O, the concentration of O₂ in the combustion air local to the system and the Air Pre-Heater Leakage Factor.

6. A method for quantifying the operation of a thermal system burning a fossil fuel having a heat exchanger/combustion region producing combustion products, the method comprising the steps of:

before on-line operation,

developing a mathematical description of the thermal system based on stoichiometric relationships and genetics of the fossil fuel based on the multi-variant analysis;

the step of operating on-line comprising the steps of

measuring a set of measurable Operating Parameters, including at least effluent concentrations of O₂ and CO₂, these measurements being made at a location downstream of the heat exchanger/combustion region of the thermal system,

obtaining an effluent concentration of H₂O, as an obtained effluent H₂O,

obtaining a fuel ash concentration selected from the group consisting of;

a constant value of fuel ash, a predictable value of fuel ash, a measured value of fuel ash determined from a fuel ash instrument and a value of fuel ash determined from an explicit solution, as an obtained fuel ash concentration,

obtaining a concentration of O₂ in the combustion air local to the system,

obtaining an Air Pre-Heater Leakage Factor, and

operating a programmed computer to obtain a complete As-Fired fuel chemistry, including fuel water and fuel ash, based on the mathematical description of the thermal system, the set of measurable Operating Parameters, the obtained effluent H₂O, the obtained fuel ash concentration, the concentration of O₂ in the combustion air local to the system and the Air Pre-Heater Leakage Factor.