Input/loss method for determining fuel flow, chemistry, heating value and performance of a fossil-fired system

A method for quantifying the operation of a fossil-fueled thermal system having a heat exchangers/combustion region wherein a fuel flow produces combustion products, the method comprising the steps of:

• operating on-line, the step of operating on-line including the steps of
• obtaining an As-Fired 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 heating value of the fuel in Btu per pound of fuel, 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 145 to 154 for weight percent carbon, from 385 to 570 for weight percent hydrogen, and from −51 to −57 for weight percent oxygen, and combinations thereof.

A method for quantifying the operation of a fossil-fueled fluidized bed thermal system producing combustion products, the method comprising the steps of:

• before on-line operation, the steps of
• obtaining reference fuel characteristics, and
• developing explicit mathematical models of the combustion process involving at least stoichiometric balances;
• and thereafter
• operating on-line, the step of operating on-line including the steps of
• measuring the measurable operating parameters, including at least
• an effluent temperature, and
• the concentration of effluent O2, CO2, and SO2, at a location downstream of a heat exchangers/combustion region of the fluidized bed thermal system;
• measuring an indicated limestone flow rate;
• measuring a useful output derived directly from the combustion products,
• calculating a complete As-Fired fuel chemistry, wherein the complete As-Fired fuel chemistry includes the elementary constituents, fuel water, and fuel ash of the fuel, and
• determining the Energy Released during Combustion based on explicit mathematical models of the combustion process and the complete As-Fired fuel chemistry,
• determining a consistent fuel flow, a consistent effluent flow, and a consistently calculated system efficiency, as a function of the measurable operating parameters, the indicated limestone flow rate, the useful output, and the complete As-Fired fuel chemistry.

A method for quantifying the operation of a fossil-fueled thermal system in which a fossil fuel is supplied at a flow rate to a heat exchangers/combustion region and combusted to produce hot combustion gases, which heats a working fluid and/or produces shaft power then exits through an exhaust stack, the method comprising the following steps:

• performing an off-line operation comprising the steps of
• obtaining reference fuel characteristics,
• obtaining reference fuel stoichiometric data,
• obtaining current measurements of the system's operating parameters, and
• performing an on-line operation comprising the steps of
• measuring the useful output of the system,
• obtaining fuel data and characteristics, the step of obtaining fuel data including the step of obtaining composite fuel concentrations and composite heating value, if multiple fuels are used,
• introducing fuel concentrations and heating values to a mathematical model of the thermal system,
• obtaining routine systems operational parameters,
• obtaining values of the effluents O2, CO2, CO, H2O, SO2 and NOx,
• obtaining the ambient concentration of O2,
• obtaining air pre-heater leakage and dilution factors,
• obtaining an indicated Air/Fuel ratio,
• computing molar moisture-ash-free fractions of fuel carbon, fuel water and fuel ash as explicit stoichiometric solutions, dependent at least in part on the effluents O2, CO2, SO2, H2O, Air/Fuel ratio, air pre-heater factors and ambient concentration of O2,
• finding the molar moisture-ash-free fractions of fuel nitrogen, oxygen, hydrogen, and sulfur,
• converting the molar moisture-ash-free fuel concentrations to a molar dry base, then to a molar As-Fired wet base, and finally to As-Fired wet weight fractions, to obtain a complete and consistent computed As-Fired fuel chemistry,
• computing a heating value based on a moisture-ash-free weight base, then converted to a dry base, and then to a weight-based As-Fired heating value, and
• executing the mathematical model of the thermal system using the fuel information and the concentration of effluent O2 to produce consistent stoichiometric values of effluent CO2, SO2 and H2O values, the Air/Fuel ratio, the moles of fuel per basis moles of dry gaseous effluent, and at least the following self-consistent thermal performance parameters:
• As-Fired fuel flow, effluent flow, emission rates, boiler efficiency, and over-all system thermal efficiency.

A method for quantifying the operation of a fossil-fueled thermal system having a heat exchangers/combustion region producing combustion products, the method comprising the steps of:

• before on-line operation, the steps of
• obtaining a set of reference fuel characteristics, and
• developing explicit mathematical models of the combustion process involving at least stoichiometric balances;
• and thereafter
• operating on-line, the step of operating on-line including 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 exchangers/combustion region of the thermal system,
• obtaining an effluent concentration of H2O if the set of reference fuel characteristics indicates that fuel water is not predictable, as an obtained effluent H2O,
• obtaining a concentration of O2 in the ambient air entering the thermal system,
• obtaining an air pre-heater leakage factor,
• calculating a set of fuel chemistry concentrations including elementary fuel constituents and fuel water, but excluding fuel ash, as a function of the set of reference fuel characteristics, explicit mathematical models of the combustion process, the set of measurable operating parameters, the obtained effluent H2O, the concentration of O2 in the ambient air entering the thermal system, and the air pre-heater leakage factor.