Method and system for monitoring corrosion or corrosive impurities associated with liquid fuel

Abstract

Method comprising: monitoring corrosion or corrosive impurities associated with liquid fuel in a fuel supply system of a gas turbine (126) comprising a fuel supply tank (128) and a fuel supply line (124), using one or more sensors (122, 130) for online real-time corrosion measurement of liquid fuels, wherein the one or more sensors (122, 130) are positioned in the fuel supply system in association with the fuel; predicting, at least partially based on monitoring, a cumulative level of corrosion of one or more hot gas path components belonging to the gas turbine (126), and outputting information associated with the monitoring.

Description

FIELD OF THE INVENTIONThis invention relates generally to the detection of contaminants in a fuel and, more particularly, to monitoring the corrosiveness of liquid fuel for use in gas turbines.BACKGROUND OF THE INVENTIONCertain fuel contaminants may promote corrosion in components associated with a gas turbine engine. Liquid fuels used for combustion in gas turbines typically include distillates and ash-containing hydrocarbon-based fuels. Contaminants may be present in the fuel and cause degradation of tanks, pipes, valves, alloy coatings and other components associated with the supply of fuel and operation of the gas turbine. Salt water, sulfur, sodium, vanadium, potassium, calcium, lead, etc. may act alone or in combination to cause corrosion. For example, oxides of sulfur and vanadium can react with other impurities to form sulfates and vanadates which are corrosive at high temperatures.The presence of contaminants in fuel can typically damage protective oxide layers on the surface of gas turbine components, such as burners, transition pieces, turbine blades, and other hot gas path (HGP) components. Further, impurities in the compressor inlet air, injected steam and water can contribute significantly to corrosion. Excessive corrosion can result in component failure, resulting in replacement of important turbine components, costly repairs, and significant time during which the engine is shut down. Small amounts of certain corrosive elements (one part per million or more) in the fuel are sufficient to cause hot corrosion.Detecting and quantifying the full amount of liquid fuel contaminants in their elemental form in an on-line continuous real-time basis is technologically challenging and has been studied by converting laboratory-scale methods to field-usable equipment including X-ray fluorescence (XRF), pulsed neutron activation analysis (PNAA), rotating disc electrode atomic emission spectroscopy (RDE-AES), electron paramagnetic resonance (EPR), and inductively coupled plasma (ICP). The leading technology for this type of measurement is XRF, for which various vendors have provided on-line real-time systems capable of measuring hydrocarbon-based liquid fuels, with the primary focus being on measuring sulfur in refinery fuel to achieve ultra-low sulfur diesel. These on-line XRF systems may be capable of detecting heavy metal impurities (vanadium and lead) to levels of single parts per million, but these XRF systems do not seem to be capable of detecting the lighter metals (sodium, potassium or calcium) at low levels.JP 3 714 413 B2 describes a method and system for monitoring the corrosion of a component, in particular a guide blade, moving blade or combustion chamber, of a gas turbine by measuring the ferrite fraction of the component by means of a ferrite probe for ferrite content measurement, determining the high-temperature corrosion on the basis of the measured ferrite content of the component and predicting the remaining service life of the component on the basis of the determined high-temperature corrosion.JP 2009-250 120 A describes a system and method for estimating corrosion and remaining life of a gas turbine component using a fuel containing a corrosive component. First, impurities contained in an introduced substance such as intake air, fuel, combustor spray water, or steam introduced into the gas turbine are analyzed. Based on the analysis result, thermodynamic calculation is performed on a combustion gas provided by burning the introduced substance as a function of temperature and pressure, predicting an operating temperature-pressure range where the corrosive component produced by combustion is in a liquid phase, and estimating the corrosion degree of a gas turbine component therefrom.It is known from EP 1 557 539 A1 to inject a corrosion-reducing substance or a corrosion-reducing additive into an intake air of the compressor in order to increase the power and efficiency of a gas turbine plant in order to avoid reaction products which cause high-temperature corrosion of gas turbine components during combustion.SUMMARY OF THE INVENTIONSome or all of the above needs may be addressed by certain embodiments of the invention. Certain embodiments of the invention may include systems, methods, and apparatus for monitoring corrosion or corrosive contaminants associated with liquid fuel.According to one aspect of the invention, a method for monitoring and predicting corrosion is provided. The method includes monitoring corrosion or corrosive contaminants associated with liquid fuel in a gas turbine fuel delivery system including a fuel delivery tank and a fuel delivery line using one or more sensors for online real-time corrosion measurement of liquid fuels, the one or more sensors positioned in the fuel delivery system in communication with the fuel, predicting, based at least in part on the monitoring, a cumulative level of corrosion of one or more hot gas path components associated with the gas turbine, and outputting information associated with the monitoring.According to another aspect of the invention, a system for monitoring and predicting corrosion is provided. The system includes a gas turbine, a fuel delivery system having at least one fuel delivery line for delivering liquid fuel to the gas turbine from a fuel delivery tank, one or more sensors for online real-time corrosion measurement of liquid fuels positioned in the at least one fuel delivery line and / or the fuel delivery tank in communication with the fuel, at least one memory for storing data and computer-executable instructions, and at least one processor configured to access the at least one memory and further configured to execute the computer-executable instructions to perform the method as described above,Other embodiments and aspects of the invention are described in detail herein and are considered part of the claimed invention. Other embodiments and aspects may be understood by reference to the following detailed description, the accompanying drawings and claims.BRIEF DESCRIPTION OF THE FIGURESReference is now made to the appended tables and drawings, which are not necessarily drawn to scale, and wherein: FIG. 1 is a block diagram of an illustrative corrosive display system according to an exemplary embodiment of the invention, FIG. 2 is a flow diagram of an example method according to an example embodiment of the invention.DETAILED DESCRIPTION OF THE INVENTIONEmbodiments of the invention will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather, these embodiments are provided so that the disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout. Embodiments of the invention enable the measurement of corrosiveness in liquid fuels of gas turbines.Embodiments of the invention include on-line real-time corrosive measurements of gas turbine liquid fuels, e.g., to determine, record, and indicate the trend of the associated hot gas path (HGP) components after fuel combustion. According to an exemplary embodiment of the invention, linear polarization resistance (LPR) corrosion sensors may be used to monitor liquid fuel in pipes supplying the fuel to the burners of the gas turbine. Certain embodiments of the invention may utilize LPR sensor corrosion rates and electrode material properties to determine the corrosiveness of the gas turbine fuel. The information from the LPR sensors may be used in conjunction with information obtained from water sensors, density sensors, and / or viscosity sensors to characterize and detect changes related to the presence of corrosive contaminants in the fuel. This corrosiveness information can be used to determine the cumulative HGP corrosion damage that occurs due to fuel combustion.In certain example embodiments, the LPR sensors may use multiple electrodes in direct contact with the liquid. The LPR electrodes may include consumable electrode material adapted to the tubular or gas turbine material such that corrosion degradation over time as caused by the corrosiveness of the fuel may be related to excitation and degradation of the electrode material. In certain example embodiments, the LPR sensors may measure a general corrosion rate, a localized pitting corrosion factor rate, and / or other parameters related to the corrosion measurement. For example, measurements of harmonic distortion or a star-Geary constant may be used to determine the integrity of the sensor signals.According to an exemplary embodiment of the invention, LPR sensors in the liquid fuel of the gas turbine may be used to measure specific corrosive compounds (e.g., salt water, which is primarily sodium) that, when burned, could cause the hot corrosion in the HGP. According to an exemplary embodiment, monitoring and determining the trend of corrosiveness by the various LPR sensor rates may be used to develop transfer functions that relate fuel corrosiveness to accumulated hot corrosion in the HGP of the gas turbine. Multiple LPR sensors using different electrode materials may be used to characterize and detect the corrosive elements of interest.Certain example embodiments of the invention may include one or more of (1) identifying the proper LPR sensor electrode material to interact with the liquid fuel contaminants causing hot corrosion; (2) placing the LPR sensor in the proper location and orientation within the liquid fuel stream to ensure that the electrode material interacts with the contaminants; (3) determining the corrosiveness of the liquid fuel based on LPR sensor measurements; (4) predicting the downstream effect of fuel corrosiveness on the HGP hot corrosion; (5) Recording and trending predicted hot corrosion to determine cumulative effect on HGP, and (6) Causes of maintenance factors and HGP component life determinations based on measurements. In certain example embodiments of the invention, a corrosion inhibitor may be injected into the fuel supply lines in response to the LPR measurements.In accordance with exemplary embodiments of the invention, various sensors, fuel supply lines, controllers, and processors may be used to monitor, predict, and detect corrosion and will now be described with reference to the accompanying figures.FIG. 1 is a block diagram of an example corrosion display system 100 according to an example embodiment of the invention. The system 100 may include a controller 102, which may include a memory 104, one or more processors 106, one or more input / output interfaces 108, and / or one or more network interfaces 110. According to example embodiments, memory 104 may include an operating system (OS) 112 and data 114. The memory 104 may also include computer-executable modules for processing input and data. For example, the memory 104 may include a prediction module 116, a trend module 118, and a remedial module 120.The system 100 includes one or more sensors 122 in communication with fuel supplied (by one or more fuel supply lines 124) to a gas turbine 126. Certain embodiments of the invention may include a sensor 130 in the tank in communication with fuel stored, e.g., in a fuel tank 128. According to certain example embodiments, the system 100 may include one or more corrosion inhibiting injectors 132 for delivering corrosion inhibitor into the fuel lines 124. In certain example embodiments, the corrosion inhibitor may be controllably delivered to the fuel lines 124 in response to, at least in part, measurements by the sensors 122, 130, or by control signals provided by the remedial action module 120.According to certain example embodiments of the invention, the controller 102 may obtain sensor measurement information from the sensors 122, 130 and provide prediction or trend information that may be used to establish or modify maintenance schedules 134 for the turbine 126, fuel supply lines 124, tank 128, and / or other components connected to the gas turbine. Certain embodiments of the invention may include auxiliary inputs and / or outputs 136 for communication with operators or additional equipment.In certain exemplary embodiments of the invention, the sensors 122, 130 may be used to monitor corrosion or corrosion contaminants associated with liquid fuel in a fuel delivery system of a gas turbine. According to an exemplary embodiment, prediction module 116 may be operated to predict a cumulative level of corrosion in the one or more components associated with a gas turbine, based at least in part on the monitoring. In accordance with exemplary embodiments of the invention, information related to monitoring, prediction, and / or trending may be provided and used by operators, or may be used in maintenance schedules 134 or to control corrosion inhibitor injectors 132. Certain example embodiments may predict the cumulative level of corrosion and estimate a remaining life associated with the one or more components associated with the gas turbine 126. In certain example embodiments, at least a portion of the information associated with the monitoring may be stored and a corrosive event trend may be determined based on at least a portion of the stored information. In example embodiments, a cumulative level of corrosion in the one or more components associated with a gas turbine may be predicted based at least in part on the monitoring.Certain example embodiments of the invention provide systems, methods, and apparatus for performing online, continuous, and / or in-situ measurements. In certain example embodiments, corrosion or corrosive contaminants associated with liquid fuel may be monitored or measured using one or more linear polarization resistance (LPR) sensors. According to certain example embodiments, the one or more sensors may include consumable electrodes. In an exemplary embodiment of the invention, measurement information associated with monitoring may be stored in the memory 104, and at least a portion of the information may be used to determine a corrosive event or trend based on at least a portion of the measurement information.According to certain example embodiments, the one or more processors 106 associated with the corrosiveness display system 100 may be configured to have access to the memory 104, and may be further configured to execute the computer-executable instructions to monitor corrosion and corrosive contaminants associated with the liquid fuel via the one or more sensors 122, 130. Example embodiments may use the prediction module 116 to predict a cumulative level of corrosion in the one or more components connected to the gas turbine 126 based at least in part on the monitoring, and output a signal associated with the monitoring. Example embodiments may also be configured to estimate a remaining lifetime associated with the one or more components.FIG. 2 is a flow diagram of an example method for monitoring and predicting corrosiveness in liquid fuels according to an example embodiment of the invention. The method 200 begins at block 202 and includes monitoring corrosion or corrosive contaminants associated with liquid fuel in a fuel delivery system of a gas turbine. At block 204, and according to an example embodiment, the method 200 includes predicting, based at least in part on the monitoring, a cumulative level of corrosion in the one or more components associated with a gas turbine. At block 206, and in accordance with an example embodiment, the method 200 includes outputting information associated with the monitoring. The method 200 ends after block 206.Accordingly, exemplary embodiments of the invention may provide the technical effects of creating certain systems, methods, and devices that monitor gas turbine fuel to provide corrosion information. Example embodiments of the invention may further provide the technical effects of predicting lives of components associated with a gas turbine based on corrosion measurements. Certain exemplary embodiments of the invention may provide the further technical effects of mitigating or minimizing damage to gas turbine components by injecting one or more corrosion inhibitors into the fuel lines when corrosive contamination has been detected. Example embodiments of the invention may provide the further technical effects of modifying maintenance schedules for the gas turbine components based on cumulative corrosion, predictions, and / or trends associated with measuring corrosion.In exemplary embodiments of the invention, corrosion display system 100 may include any number of hardware and / or software applications that are executed to facilitate any of the operations. In example embodiments, one or more input / output (I / O) interfaces may facilitate communication between the corrosion display system 100 and one or more input / output devices. For example, a universal row bus opening, a row opening, a floppy disk drive, a CD-ROM drive, and / or one or more user interface devices, such as a display, keyboard, pillows, mouse, control disk, touch screen, microphone, etc., may facilitate user interaction with the corrosion display system 100. The one or more I / O interfaces may be used to receive or collect data and / or user instructions from a wide variety of input devices. Received data may be processed by one or more computer processors, as desired in various embodiments of the invention, and / or stored in one or more storage devices.One or more network interfaces may facilitate connection of the inputs and outputs of the corrosion display system 100 to one or more suitable networks and / or connections; e.g., the connections that facilitate communication with any number of sensors connected to the system. The one or more network interfaces may further facilitate connection to one or more suitable networks, e.g., a local area network, a wide area network, the Internet, a cellular network, a radio frequency network, a Bluetooth™ (the Telephone Impact LM Ericsson) network, a released Wi-Si™ (the Wi-Fi Alliance) network, a satellite-based network, any wired network, any wireless network, etc., for communication with external devices and / or systems. As desired, embodiments of the invention may include the corrosion display system 100 having more or less of the components illustrated in FIG. 1.The invention is described above with reference to block and flow diagrams of the systems, methods, apparatus and / or computer program products according to exemplary embodiments of the invention. It should be understood that one or more blocks of the block diagrams and flowcharts, and combinations of blocks in the block diagrams and flowcharts, may be executed by computer-executable program instructions. Likewise, in accordance with some embodiments of the invention, some blocks of the block diagrams and flow charts need not necessarily be executed in the order given or need not necessarily be executed at all.These computer-executable program instructions may be loaded onto a general purpose computer, a special purpose computer, a processor, or other programmable data processing apparatus to produce a special purpose machine such that the instructions executed on the computer, processor, or other programmable data processing apparatus produce means for executing one or more functions specified in the flowchart block or blocks. These computer program instructions may also be stored in a computer readable memory that directs a computer or other programmable data processing apparatus to function in a particular manner such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means that perform one or more functions specified in the flowchart block or blocks. As an example, embodiments of the invention may provide a computer program product comprising a computer usable medium having computer readable program code or program instructions embodied therein, the computer readable program code adapted to be executed to perform one or more functions specified in the flowchart block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operating elements or stages to be executed on the computer or other programmable apparatus to produce a computer-executed process such that the instructions executed on the computer or other programmable apparatus provide elements or stages for executing the functions specified in the flowchart block or blocks.Blocks of the block diagrams and flow charts accordingly support combinations of means for executing the specified functions, combinations of elements or stages for executing the specified functions, and program instruction means for executing the specified functions. It should also be understood that each block of the block diagrams and flow charts, and combinations of blocks in the block diagrams and flow charts, may be executed by special purpose hardware-based computer systems or combinations of special purpose hardware and computer instructions that perform the specified functions, elements, or stages.While the invention has been described in connection with what is at present considered to be the most practical and various embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims. Although specific terms have been used herein, they are used in a generic and descriptive sense only and not for purposes of limitation.This specification uses examples to disclose the invention, including the best mode, and also to enable one skilled in the art to practice the invention, including making and using any devices or systems and performing any intrinsic methods. The patentable scope of the invention is defined in the claims and may include other examples that will occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that do not differ from the wording of the claims, or if they include equivalent structural elements with insubstantial differences from the wording of the claims.Certain embodiments of the invention may include systems, methods, and apparatus for monitoring corrosion or corrosive contaminants associated with liquid fuel. According to an exemplary embodiment of the invention, a method for monitoring and predicting corrosion is provided. The method may include monitoring corrosion or corrosive contaminants associated with liquid fuel in a fuel delivery system of a gas turbine, predicting, based at least in part on the monitoring, a cumulative level of corrosion of one or more components associated with a gas turbine, and outputting information associated with the monitoring.LIST OF REFERENCE CHARACTERS100 Corrosiveness Indicator System 102 Controller 104 Memory 106 Processor(s) 108 In / Out Interface(s) 110 Network Interface(s) 112 Operating System 114 Data 116 Corrosion Prediction Module(s) 118 Corrosion Trend Module(s) 120 Remedial Module(s) 122 Sensors 124 Fuel Supply Line 126 Gas Turbine 128 Fuel Supply Tank 130 Fuel Supply Sensor 132 Corrosion Inhibition Injector 134 Maintenance Schedule 136 Auxiliary Inputs / Outputs 200 Method Flow Diagram 202 Block 204 Block 206 Block

Claims

A method comprising: monitoring corrosion or corrosive contaminants associated with liquid fuel in a fuel delivery system of a gas turbine (126) comprising a fuel delivery tank (128) and a fuel delivery line (124) using one or more sensors (122, 130) for online real-time corrosion measurement of liquid fuels, wherein the one or more sensors (122, 130) are positioned in the fuel delivery system in communication with the fuel; predicting, based at least in part on the monitoring, a cumulative level of corrosion of one or more hot gas path components associated with the gas turbine (126); and outputting information associated with the monitoring.The method of claim 1, wherein predicting the cumulative level of corrosion comprises estimating a remaining lifetime associated with the one or more hot gas path components.The method of claim 1, further comprising performing preventative maintenance based at least in part on the monitoring on the one or more hot gas path components associated with the gas turbine (126).The method of claim 1, further comprising injecting one or more corrosion inhibitors into the fuel delivery system based at least in part on the monitoring.The method of claim 1, wherein the on-line real-time corrosion measurements for monitoring are performed as continuous measurements.The method of claim 1, wherein monitoring comprises measuring corrosion or corrosive contaminants of the liquid fuel using one or more linear polarization resistance (LPR) sensors.The method of claim 1, wherein the monitoring includes measuring corrosion or corrosive contaminants of the liquid fuel using one or more sensors, the one or more sensors comprising a linear polarization resistance (LPR) sensor and / or a consumable electrode and / or a water sensor and / or a density sensor and / or a viscosity sensor.The method of claim 1, further comprising storing at least a portion of the information associated with the monitoring and determining a corrosive event trend based at least in part on the stored information.A system comprising: a gas turbine (126); a fuel delivery system having at least one fuel delivery line (124) for delivering liquid fuel to the gas turbine (126) from a fuel delivery tank (128); one or more sensors (122, 130) for online real-time corrosion measurement of liquid fuels positioned in the at least one fuel delivery line (124) and / or the fuel delivery tank (128) in communication with the fuel; at least one memory (104) for storing data (114) and computer-executable instructions; and at least one processor (106) configured to access the at least one memory (104) and further configured to execute the computer-executable instructions to perform the method of claim 1.The system of claim 9, wherein the one or more sensors (122, 130) comprise at least one linear polarization resistance (LPR) sensor and / or a consumable electrode and / or a water sensor and or a density sensor and / or a viscosity sensor.

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