L factor method for determining heat rate of a fossil fired system based on effluent flow
First Claim
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1. A method for quantifying the operation of a fossil-fired system, the method comprising the steps of:
- obtaining an L Factor;
determining a correction to the L Factor which converts its applicability from theoretical combustion to combustion associated with the fossil-fired system, and if applicable the correction for the system heating value base, and if applicable conversion to a wet-base L Factor;
combining the L Factor and the correction to the L Factor, resulting in a corrected L Factor;
obtaining a total effluents flow rate from the fossil-fired system;
obtaining a correction factor for the total effluents mass flow rate, resulting in a corrected total effluents mass flow rate; and
dividing the corrected total effluents flow rate by the corrected L Factor, resulting in a total fuel energy flow of the system.
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Abstract
The operation of a fossil-fueled thermal system is quantified by obtaining effluent flow, the L Factor and other operating parameters to determine and monitor the unit'"'"'s heat rate and to determine the emission rates of its pollutants.
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Citations
15 Claims
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1. A method for quantifying the operation of a fossil-fired system, the method comprising the steps of:
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obtaining an L Factor;
determining a correction to the L Factor which converts its applicability from theoretical combustion to combustion associated with the fossil-fired system, and if applicable the correction for the system heating value base, and if applicable conversion to a wet-base L Factor;
combining the L Factor and the correction to the L Factor, resulting in a corrected L Factor;
obtaining a total effluents flow rate from the fossil-fired system;
obtaining a correction factor for the total effluents mass flow rate, resulting in a corrected total effluents mass flow rate; and
dividing the corrected total effluents flow rate by the corrected L Factor, resulting in a total fuel energy flow of the system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
obtaining a total effluents volumetric flow rate from the fossil-fired system;
obtaining a density of the total effluents; and
obtaining the total effluents flow rate by multiplying the total effluents volumetric flow rate by the density of the total effluents.
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3. The method of claim 1, including additional steps, after the step of dividing the corrected total effluents, of:
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obtaining a produced electrical power from the fossil-fired system; and
dividing the total fuel energy flow of the system by the produced electrical power, resulting in a heat rate of the fossil-fired system.
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4. The method of claim 1, including additional steps, after the step of dividing the corrected total effluents, of:
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obtaining a fuel heating value of the fuel consumed by the fossil-fired system; and
dividing the total fuel energy flow of the system by the fuel heating value, resulting in a fuel flow rate of the fossil-fired system.
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5. The method of claim 4, including additional steps, after the step of dividing the total fuel energy flow, of:
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obtaining a turbine cycle energy flow;
obtaining a boiler efficiency;
obtaining a turbine cycle based fuel flow rate by dividing the turbine cycle energy flow by the product of the boiler efficiency and the fuel heating value; and
adjusting the turbine cycle energy flow until the turbine cycle based fuel flow rate and the fuel flow rate are in reasonable agreement.
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6. The method of claim 1, including additional steps, after the step of dividing the corrected total effluents, of:
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obtaining a fuel flow rate of the fossil-fired system; and
dividing the total fuel energy flow of the system, by the fuel flow rate, resulting in the fuel heating value of the fuel consumed by the fossil-fired system.
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7. The method of claim 6, including additional steps, after the step of dividing the total fuel energy flow, of:
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obtaining a turbine cycle energy flow;
obtaining a boiler efficiency;
obtaining a turbine cycle based fuel flow heating value by dividing the turbine cycle energy flow by the product of the boiler efficiency and the fuel flow rate; and
adjusting the turbine cycle energy flow until the turbine cycle based fuel heating value and the fuel heating value are in reasonable agreement.
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8. The method of claim 1, wherein the step of determining the correction to the L Factor comprises the steps of:
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obtaining a combustion air flow rate of the fossil-fired system by on-line monitoring;
obtaining a fuel flow rate of the fossil-fired system by on-line monitoring;
determining a correction for the system heating value base used by the fossil-fired system;
determining an on-line correction to the L Factor by combining the combustion air flow rate, the fuel flow rate and, if applicable, the correction for the system heating value base; and
obtaining a corrected L Factor by combining the L Factor and the on-line correction to the L Factor.
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9. The method of claim 1, wherein the step of obtaining the L Factor, includes the step of:
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determining that the fossil fuel is a coal;
determining a set of properties associated with the coal;
determining a rank for the coal from the set of properties, said rank to be either an anthracite coal, or a semi-anthracite coal, or a low volatile bituminous coal, or a medium volatile bituminous coal, or a high volatile A bituminous coal, or a high volatile B bituminous coal, or a high volatile C bituminous coal, or a sub-bituminous A coal, or a sub-bituminous B coal, or a sub-bituminous C coal, or a lignite A coal, or a lignite B coal;
depending on the rank of the coal, establishing the L Factor for the anthracite coal between 819.36 and 835.83 lbm/million-Btu, or establishing the L Factor for the semi-anthracite coal between 796.14 and 812.14 lbm/million-Btu, or establishing the L Factor for the low volatile bituminous coal between 784.97 and 800.75 lbm/million-Btu, or establishing the L Factor for the medium volatile bituminous coal between 778.81 and 794.47 lbm/million-Btu, or establishing the L Factor for the high volatile A bituminous coal between 774.19 and 789.75 lbm/million-Btu, or establishing the L Factor for the high volatile B bituminous coal between 775.33 and 790.91 lbm/million-Btu, or establishing the L Factor for the high volatile C bituminous coal between 776.82 and 792.43 lbm/million-Btu, or establishing the L Factor for the sub-bituminous A coal between 780.45 and 796.14 lbm/million-Btu, or establishing the L Factor for the sub-bituminous B coal between 779.28 and 794.94 lbm/million-Btu, or establishing the L Factor for the sub-bituminous C coal between 780.86 and 796.56 lbm/million-Btu, or establishing the L Factor for the lignite A coal between 788.63 and 804.49 lbm/million-Btu, or establishing the L Factor for the lignite B coal between 758.39 and 773.63 lbm/million-Btu.
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10. The method of claim 1, wherein the step of obtaining the L Factor, includes the step of:
establishing a ratio of non-oxygen gases to oxygen used for ambient air conditions which is greater than a value of 3.7619 and less than a value of 3.7893.
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11. The method of claim 1, wherein the step of obtaining the total effluents flow rate includes the step of:
obtaining a total effluents mass flow rate from the fossil-fired system.
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12. The method of claim 1, wherein the step of determining the correction to the L Factor includes the steps of:
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obtaining a ratio of actual dry-gas effluent mass flow to actual wet fuel mass flow;
obtaining a ratio of the ratio of the theoretical wet fuel mass flow to the theoretical dry-gas effluent mass flow; and
multiplying the ratio of actual dry-gas effluent mass flow to actual wet fuel mass flow by the ratio of the ratio of the theoretical wet fuel mass flow to the theoretical dry-gas effluent mass flow resulting in the correction to the L Factor.
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13. The method of claim 1, wherein the step of determining the correction to the L Factor includes the steps of:
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obtaining a ratio of actual dry-gas effluent volumetric flow to theoretical dry-gas effluent volumetric flow;
obtaining a ratio of the actual dry-gas density to the theoretical dry-gas density used to convert the ratio of actual dry-gas effluent volumetric flow to theoretical dry-gas effluent volumetric flow;
obtaining a ratio of the ratio of the theoretical wet fuel mass flow to the actual wet fuel mass flow; and
multiplying the ratio of actual dry-gas effluent volumetric flow to theoretical dry-gas effluent volumetric flow by the ratio of the actual dry-gas density to the theoretical dry-gas density by the ratio of the ratio of the theoretical wet fuel mass flow to the actual wet fuel mass flow resulting in the correction to the L Factor.
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14. The method of claim 12, wherein the step of obtaining the ratio of actual dry-gas effluent mass flow to actual wet fuel mass flow includes the steps of:
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obtaining an actual air/fuel ratio;
obtaining a weight fraction of water in the fossil fuel;
obtaining a weight fraction of ash in the fossil fuel; and
combining the actual air/fuel ratio, the weight fraction of water and the weight fraction of ash resulting in the ratio of actual dry-gas effluent mass flow to actual wet fuel mass flow.
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15. The method of claim 12, wherein the step of obtaining the ratio of the theoretical wet fuel mass flow to the theoretical dry-gas effluent mass flow includes the steps of:
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obtaining a molecular weight of the wet fuel;
obtaining a molecular weight of the wet-gas effluent based on theoretical combustion;
obtaining a ratio of the moles of wet fuel required to produce 100 moles of wet-gas effluent based on theoretical combustion; and
combining the molecular weight of the wet fuel, the molecular weight of the wet-gas effluent and the ratio of the moles of wet fuel required to produce 100 moles of wet-gas effluents resulting in the ratio of the theoretical wet fuel mass flow to the theoretical dry-gas effluent mass flow.
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Specification