Method for detecting heat exchanger tube failures and their location when using input/loss performance monitoring of a power plant
AssigneeExergetic Systems LLC
InventorFred D Lang
Life of this patent
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Abstract
This invention relates to a fossil-fired thermal system such as a power plant or steam generator, and, more particularly, to a method for rapid detection of tube failures and their location with the steam generator, without need for direct instumentation, thereby preventing more serious damage and minimizing repair time on the effected heat exchanger. This method is applicable to Input/Loss methods of monitoring fossil-fired thermal systems.
Claims43
A method for quantifying the operation of a fossil-fired thermal system through knowledge of when its heat exchanger leaks working fluid into the combustion gas path producing a tube leakage, the method for quantifying the operation comprising the steps of:
- monitoring the fossil-fired thermal system by one of the Input/Loss methods,
- developing a mathematical model of the combustion process incorporating terms commonly associated with fossil fuel combustion and terms associated with sources of working fluid flows into the combustion gas path including tube leakage resulting in a stoichiometric model of the combustion process using a molar base, and
- determining a tube leakage in moles based on the stoichiometric model of the combustion process using a molar base.
A method for quantifying the operation of a fossil-fired thermal system when being monitored by one of the Input/Loss methods through knowledge of when its heat exchanger leaks working fluid into the combustion gas path producing a tube leakage, the method for quantifying the operation comprising the steps of:
- developing a mathematical model of the combustion process incorporating terms commonly associated with fossil fuel combustion and terms associated with sources of working fluid flows into the combustion gas path including tube leakage resulting in a stoichiometric model of the combustion process,
- selecting a set of minimization techniques applicable to the thermal system and its fuel, and a set of routine inputs and convergence criteria to the minimization techniques,
- selecting a Choice Operating Parameter of tube leakage flow rate,
- selecting a set of routine Choice Operating Parameters,
- determining a set of System Effect Parameters applicable to the thermal system and its fuel whose functionalities effect the determination of system heat rate and are sensitive to tube leakage flow rate,
- determining a set of Reference System Effect Parameters applicable to the set of System Effect Parameters,
- determining an objective function applicable to the thermal system's stoichiometric situation which uses the Choice Operating Parameter of tube leakage flow rate, the set of routine Choice Operating Parameters, the set of System Effect Parameters, and the set of Reference System Effect Parameters,
- optimizing the Choice Operating Parameter of tube leakage flow rate and the set of routine Choice Operating Parameters based on the mathematical model of the combustion process, the set of minimization techniques and the objective function such that convergence criteria is met resulting in a set of converged Choice Operating Parameters including the tube leakage flow rate, and
- reporting the tube leakage flow rate such that corrective action may take place.
A method for quantifying the operation of a fossil-fired thermal system when being monitored on-line by The Input/Loss Method through knowledge of when its heat exchanger leaks working fluid into the combustion gas path producing a tube leakage flow rate, the method comprising the steps of:
- before on-line operation,
- developing a mathematical model of the combustion process incorporating terms commonly associated with fossil fuel combustion and terms associated with sources of working fluid flows into the combustion gas path including tube leakage resulting in a stoichiometric model of the combustion process, and
- selecting a set of minimization techniques applicable to the thermal system and its fuel, and a set of routine inputs and convergence criteria to the minimization techniques;
- and thereafter
- performing a Pass 0 monitoring cycle while operating on-line which determines a trip mechanism associated with a tube leakage flow rate, comprising the steps of:
- assuming a tube leakage flow rate is zero,
- selecting a set of routine Choice Operating Parameters,
- determining a set of System Effect Parameters applicable to the thermal system and its fuel whose functionalities effect the determination of system heat rate, and determining applicable Reference System Effect Parameters,
- performing a Pass 0 monitoring cycle using The Input/Loss Method resulting in a set of fuel concentrations and correction factors to the set of routine Choice Operating Parameters,
- testing the set of fuel concentrations and correction factors against a set of corresponding limits resulting in a trip mechanism indicating the stoichiometric reason how a heat exchanger may leak a tube leakage flow rate into the combustion gas path, and
- assuming the trip mechanism indicates a tube leakage flow rate is possible;
- and thereafter
- performing a Pass 1 monitoring cycle while operating on-line which determines a tube leakage flow rate, comprising the steps of:
- multiplying a value of uncorrected effluent water concentration by a reference correction factor resulting in a constant effluent water concentration,
- multiplying a value of uncorrected effluent carbon dioxide concentration by a reference correction factor resulting in a constant effluent carbon dioxide concentration,
- selecting a set of routine Choice Operating Parameters including tube leakage flow rate but excluding effluent water and carbon dioxide,
- determining a set of System Effect Parameters applicable to the thermal system and its fuel whose functionalities effect the determination of system heat rate and are sensitive to tube leakage flow rate, and determining applicable Reference System Effect Parameters,
- performing a Pass 1 monitoring cycle using The Input/Loss Method resulting in a set of converged Choice Operating Parameters including the tube leakage flow rate, and thereafter;
- reporting the tube leakage flow rate such that corrective action may take place.
A method for quantifying the operation of a fossil-fired thermal system when being monitored by one of the Input/Loss methods through knowledge of a stoichiometric mechanism of how a heat exchanger could be leaking a tube leakage flow rate into the combustion gas path, the method for quantifying the operation comprising the steps of:
- developing a mathematical model of the combustion process incorporating terms commonly associated with fossil fuel combustion and terms associated with sources of working fluid flows into the combustion gas path including tube leakage,
- obtaining a set of Choice Operating Parameters,
- obtaining a set of Reference Fuel Characteristics,
- obtaining a fuel chemistry of the fuel being combusted by the thermal system using one of the Input/Loss methods, the mathematical model of the combustion process, the set of Choice Operating Parameters, and the set of Reference Fuel Characteristics, said fuel chemistry resulting in a set of fuel concentrations,
- establishing a set of concentration limits for each fuel constituent based on Reference Fuel Characteristics,
- testing the set of fuel concentrations against the set of concentration limits resulting in a trip mechanism indicating the stoichiometric reason how a heat exchanger leaks a tube leakage flow rate into the combustion gas path, and
- reporting the trip mechanism to the operator of the thermal system.
A method for quantifying the operation of a fossil-fired thermal system when being monitored by one of the Input/Loss methods through knowledge of a stoichiometric mechanism of how a heat exchanger could be leaking a tube leakage flow rate into the combustion gas path, the method for quantifying the operation comprising the steps of:
- developing a mathematical model of the combustion process incorporating terms commonly associated with fossil fuel combustion and terms associated with sources of working fluid flows into the combustion gas path including tube leakage,
- 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,
- assuming a tube leakage flow rate is zero,
- selecting a set of routine Choice Operating Parameters,
- 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 applicable to the set of System Effect Parameters,
- determining an objective function applicable to the thermal system, the set of routine Choice Operating Parameters, the set of System Effect Parameters and the set of Reference System Effect Parameters,
- optimizing the set of routine Choice Operating Parameters based on the mathematical model of the combustion process, the set of minimization techniques, and the objective function such that convergence is met resulting in a set of converged Choice Operating Parameters,
- determining a fuel chemistry of the fuel being combusted by the thermal system using one of the Input/Loss methods, the mathematical model of the combustion process, the set of converged Choice Operating Parameters, and Reference Fuel Characteristics resulting in a fuel elementary composition, a fuel ash fiction and a fuel water fraction said composition and fractions resulting in a set of fuel concentrations,
- establishing a set of concentration limits for the set of fuel concentrations based on Reference Fuel Characteristics,
- testing the set of fuel concentrations against the set of concentration limits resulting in a trip mechanism indicating the stoichiometric reason how a heat exchanger leaks a tube leakage flow rate into the combustion gas path, and
- reporting the trip mechanism to the operator of the thermal system.
A method for quantifying the operation of a thermal system burning a fossil fuel in a combustion process through knowledge of when one of its heat exchangers, whose tubes contain working fluid heated by products of combustion, has a tube leak of working fluid mixing with the products of combustion, the method for quantifying the operation comprising the steps of:
- selecting a neural network technology applicable to the thermal system,
- selecting a set of routine inputs and database for the neural network technology,
- selecting a set of Choice Operating Parameters including tube leakage flow rate,
- developing a mathematical model of the combustion process incorporating terms commonly associated with a combustion process and terms associated with sources of working fluid mixing with the products of combustion including tube leakage,
- obtaining a set of Reference System Effect Parameters associated with the thermal system,
- calculating a set of System Effect Parameters based on the mathematical model of the combustion process,
- optimizing the set of Choice Operating Parameters including tube leakage flow rate using the neural network technology, and the set of routine inputs and database, the set of Reference System Effect Parameters and the set of System Effect Parameters, such that convergence is met resulting in a set of converged Choice Operating Parameters including a tube leakage flow rate, and
- reporting the tube leakage flow rate such that corrective action may take place.
A method for quantifying the operation of a fossil-fired thermal system when being monitored by one of the Input/Loss methods coincident with one of its heat exchangers leaking its working fluid into the combustion gas path producing a tube leakage flow, the method for quantifying the operation by identification of the leaking heat exchanger comprising the steps of:
- identifying a set of heat exchangers descriptive of the thermal system as employed to transfer net energy flow to the working fluid from the combustion gases resulting in a set of identified heat exchangers,
- obtaining a set of Operating Parameters applicable to the set of identified heat exchangers,
- analyzing a set of net energy flows to the working fluid from the combustion gases based on the set of identified heat exchangers, the set of Operating Parameters and the tube leakage flow rate, each analyzed set descriptive of the thermal system and wherein each analyzed set the tube leakage flow rate is assigned to a different heat exchanger, resulting in an analyzed set of heat exchangers,
- determining a reference key comparative parameter for the thermal system,
- obtaining a set of key comparative parameters associated with each identified heat exchanger, applicable with the reference key comparative parameter, and based on the analyzed set of heat exchangers,
- determining a set of deviations between the set of key comparative parameters and the reference key comparative parameter,
- determining an identification of the leaking heat exchanger based on the set of deviations, and
- reporting to the operator of the thermal system the identification of the leaking heat exchanger such that corrective action may take place.
A method for quantifying the operation of a thermal system burning a fossil fuel in a combustion process through knowledge of when one of its heat exchangers, whose tubes contain working fluid heated by products of combustion, has a tube leak of working fluid mixing with the products of combustion, the method for quantifying the operation comprising the steps of:
- monitoring the thermal system using one of the Input/Loss methods,
- developing a mathematical model of the combustion process incorporating terms commonly associated with the combustion process and terms associated with sources of working fluid mixing with the products of combustion including tube leakage,
- determining a tube leakage based on the mathematical model of the combustion process, and
- reporting the tube leakage such that corrective action may take place.
A method for quantifying the operation of a thermal system burning a fossil fuel in a combustion process through knowledge of when one of its heat exchangers, whose tubes contain working fluid heated by products of combustion, has a tube leak of working fluid mixing with the products of combustion, the method for quantifying the operation comprising determining a location of the heat exchanger within the thermal system with the tube leak based on the working fluid's energy flow by assigning the tube leak to different heat exchangers.
Dependencies are inferred from the claim text.