Abstract:
An apparatus  20  may include a generator  22  and a combustion turbine  24  for driving the generator, the combustion turbine having an air inlet  40  for receiving an inlet air flow. The apparatus may also include an inlet air flow sampling sensor  26.  The inlet air flow sampling sensor  26,  in turn, may include a solution container  46  for containing a solution  50  for sampled air from the inlet air flow. The inlet air flow sampling sensor  26  additionally may include sensing circuitry for sensing at least one dissolved material in the solution  50.  For example, the material may be salt, such as found in the inlet air for coastal power plants.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to the field of combustion turbines, and, more particularly, to sensors for combustion turbines.  
         BACKGROUND OF THE INVENTION  
         [0002]    Combustion turbines are used to power a wide variety of equipment, including ships, aircraft, and power generators. For example, a typical electrical generator includes a stator and a rotor that turns within the stator to generate electrical power. To drive the rotor, a shaft is connected to a combustion turbine, and the combustion turbine drives the shaft.  
           [0003]    In a conventional configuration, the combustion turbine comprises a compressor to draw in and compress a gas, a combustor or heat source to add energy in the form of heat to the compressed gas, and a turbine to extract power from the heated gas. In an electrical generator, the extracted power is used to drive the shaft, which, as already noted, rotates the rotor within the stator to thus generate electricity.  
           [0004]    The gas used in the combustion turbine is usually ambient air drawn from the surrounding environment. Although combustion turbine generators provide many advantages in terms of efficiency and reliability as compared to many other types of machines, the use of ambient air can be problematic depending on the nature of the environment in which the combustion turbine is operated. As observed in U.S. Pat. No. 4,060,001 to Archerd, for example, a combustion turbine near a body of seawater is susceptible to the corrosive effects of salt carried by the air drawn into the combustion turbine. This, then, would be a problem with combustion turbines used, for example, to power a ship or a power generator located near a seacoast.  
           [0005]    A filter may be installed upstream of an inlet to the combustion turbine, but if saltwater mist, for example, saturates the filter, then salt particles can migrate through the filter media and enter the combustion turbine. Similarly, if salt builds up over time on the filter, then, again, the salt may enter the combustion turbine by migrating through the filter.  
           [0006]    The Archerd patent cited above discloses an isokinetic sampling nozzle attached to a flow amplifier that utilizes the Coanada wall attachment effect for capturing samples of ambient air. The sampled air can be analyzed to determine whether there are contaminants in the ambient air.  
           [0007]    European Pat. 384392 to Forfitt et al., discloses electrostatic probes that connect to the combustion chamber of a combustion turbine and that supply signals to a processor. The processor processes signals from the probes indicating the occurrence of certain events in the combustion turbine, including the intake of debris such as stones, sand, or salt that carry electrostatic charges.  
           [0008]    Notwithstanding the availability of isokinetic sampling and electrostatic charge detection, difficulties remain with respect to monitoring the intake of contaminating materials into a combustion turbine power generator. For example, because salt can exist as a dissolved solid in a liquid droplet, or as a very fine particle left after the water evaporates, it may be difficult to effectively or efficiently measure salt in an inlet air flow to the combustion turbine.  
         SUMMARY OF THE INVENTION  
         [0009]    In view of the foregoing background, it is therefore an object of the present invention to provide effective and efficient sampling and analyzing of inlet air drawn from the inlet air flow received into a combustion turbine.  
           [0010]    This and other objects, features, and advantages in accordance with the present invention are provided by an inlet air flow sampling sensor comprising a solution container and sensing circuitry associated therewith. The solution container may contain a solution through which sampled air is passed. Accordingly, materials from the sampled air may be extracted and dissolved in the solution. The sensing circuitry may sense at least one dissolved material in the solution, such as salt, for example. The sampling is thus accurate, and can be efficiently used in a continuous operating mode, for example.  
           [0011]    The sensing circuitry may comprise at least one ion-selective electrode that can be immersed in the solution. The sensing circuitry also may comprise a reader connected to the ion-selective electrode. The reader may display a concentration of the selected material, such as salt.  
           [0012]    The sensing circuitry may further comprise a data logger connected to the reader. The data logger may log data based on the signals generated by the ion-selective electrode. Additionally, the sensing circuitry may comprise a data analyzer connected to the reader either directly or through the data logger. The data analyzer may provide analysis, extrapolate trends, or generate predictions based on the data logged by the logger.  
           [0013]    The at least one ion-selective electrode and the reader, moreover, may be for dissolved salt. Accordingly, the sensing circuitry may determine, with respect to the sampled air from the inlet air flow, that salt is being carried by the inlet air flow and in what amount. Other contaminants can be similarly measured and monitored. The amount of contaminants affecting the combustion turbine, accordingly, can be measured and recorded over time.  
           [0014]    The inlet air flow sampling sensor may additionally comprise a sampling probe. The sampling probe may be connected to be in fluid communication with and between the inlet air flow and the solution container. More particularly, the sampling probe may comprise an isokinetic sampling probe for greater sampling accuracy. The sampling probe may advantageously continuously sample the inlet air flow during operation of the combustion turbine. The apparatus may also typically include an inlet air filter, in which event, the inlet air flow sampling sensor may be downstream from the inlet air filter.  
           [0015]    An additional aspect of the invention relates to a method for sampling an inlet air flow for a combustion turbine. The method may comprise passing sampled air from the inlet air flow through a solution to dissolve materials from the sampled air in the solution, and sensing at least one dissolved material therein using sensing circuitry.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a schematic view of an apparatus according to the present invention.  
         [0017]    [0017]FIG. 2 is a more detailed schematic view of the inlet air flow sampling sensor of the apparatus of FIG. 1.  
         [0018]    [0018]FIG. 3 is a flow diagram of a method according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred 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. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.  
         [0020]    Referring initially to FIG. 1, an apparatus  20  according to the present invention is described. Illustratively, the apparatus includes a combustion turbine  24  that can be used to mechanically power other equipment and machinery and an inlet air flow sampling sensor  26  for detecting and measuring the concentration of contaminating materials in an inlet air flow  41  received by the combustion turbine.  
         [0021]    The combustion turbine  24  illustratively comprises a compressor section  34 , a combustor section  36  downstream from the compressor section, and a turbine section  38  downstream from the combustor section. As will be readily understood by those skilled in the art, the inlet air flow  41  is received into the compressor section  34  through an air inlet  40 . The inlet air is compressed and fuel is added to it in the combustor section  36  to thereby power the turbine section  38 , as will also be readily understood by those skilled in the art.  
         [0022]    Contaminating materials, of course, can be carried by the inlet air flow  41  into the combustion turbine  24 . For example, if the combustion turbine  24  were operated at sea or near a coastline, there would be a possibility that saltwater mist would mix with the inlet air flow  41  and be carried into the combustion turbine  24 . Accordingly, as illustrated, a filter housing  42  with a filter  44  carried therein is positioned upstream from the air inlet  40  of the combustion turbine  24  to filter contaminating materials from the inlet air flow  41 .  
         [0023]    Despite the presence of the filter  44 , contaminating materials may yet reach the combustion turbine  24 . For example, if saltwater saturates the filter  44 , salt may migrate through the filter media and enter the combustion turbine  24 . Likewise, if over time, salt builds up on the filter  44 , it may also reach the combustion turbine  24 . One skilled in the art will readily appreciate that other contaminating materials can also enter the combustion turbine  24  in a similar manner. Contaminating materials such as salt, for example, are known to cause corrosion of the internal components of the combustion turbine  24 . It is therefore advisable to monitor the inlet air flow  41  to determine whether and to what extent contaminating materials may be entering the combustion turbine  24  borne by the inlet air flow  41  and received through the air inlet  40 .  
         [0024]    The determinations can be used to decide whether the filter  44  is functioning properly or whether it ought to be serviced or replaced. They can also be used in calculating how soon and/or how often maintenance (e.g., replacement of the filter) should be performed. Maintenance, accordingly, can be scheduled in advance. As discussed more fully below, the nature and amount of contaminants to which the combustion turbine  24  has been subjected may be recorded over time for analysis of their cumulative effect on the combustion turbine  24 . The determinations and analysis are facilitated by inclusion in the apparatus  20  of the inlet air flow sampling sensor  26 , which is illustratively positioned downstream from the inlet air filter  44 .  
         [0025]    Referring additionally now to FIG. 2, the inlet air flow sampling sensor  26  illustratively comprises a solution container  46  and, associated therewith, sensing circuitry  48 . A solution  50  may be contained in the solution container  46 , and sampled air drawn from the inlet air flow  41  may be introduced into or passed through the solution  50  so that materials carried by the sampled air may be dissolved in the solution, as will be readily understood by those skilled in the art. For example, sampled air may be passed through the solution  50  by bubbling the air into the solution.  
         [0026]    The sensing circuitry  48  senses at least one material dissolved in the solution. For example, if the inlet air flow  41  carries salt, then when the sampled air is passed through the solution  50 , such as water, the salt is dissolved in the water. Dissolved in the water, the salt yields sodium and chloride ions, as will be readily understood by those skilled in the art. Accordingly, the sensing circuitry  48  may sense for one or both of sodium and chloride ions.  
         [0027]    In the embodiment illustrated in FIG. 2, the sensing circuitry  48  further comprises an ion-selective electrode  52 . The ion-selective electrode  52  may be immersed in the solution  50  contained in the solution container  46 . The ion-selective electrode  52 , as will be readily understood by one skilled in the art, can generate an electrical signal in response to the presence of a particular ion. The signal, moreover, may be a function of the concentration of the ion in the solution  50 , as will also be readily appreciated by those skilled in the art.  
         [0028]    Thus, referring again to the earlier example, if salt is dissolved in the solution  50 , which, again, may comprise water, then the ion-selective electrode  52  can provide a signal indicating the concentration of sodium and/or chloride ions in the water. As will be readily appreciated by those skilled in the art, additional ion-selective electrodes can be added as desired to indicate the presence and concentration of various different contaminating materials and their ions.  
         [0029]    The ion concentration of the solution  50 , moreover, reflects an amount of corresponding material borne by the inlet air flow  41 , as will be readily appreciated by those skilled in the art. It, therefore, can be used to assess the amount of a contaminating material entering the combustion turbine  24 .  
         [0030]    The sensing circuitry  48  also illustratively comprises a reader  54  connected to the ion-selective electrode  52  for providing a conveniently read indication of the presence and/or concentration of a contaminating material. The reader  54  may be a simple meter that gives, for example, a voltage or current reading commensurate with the concentration of a particular ion in the solution  50 . Alternatively, the reader  54  may comprise a more complex processor specifically programmed for such readings. Still further, the reader  54  alternately may be a processor associated with a general-purpose, programmable computer, as will be readily understood by those skilled in the art.  
         [0031]    The sensing circuitry  48  further illustratively comprises a data logger  56  connected to the reader  54 . The data logger  56  may be a discrete circuit dedicated to logging readings generated by the reader  54 , or, alternately, it may be a register or memory associated with a general-purpose, programmable computer and for storing data generated by a processor, as will, again, be readily understood by those skilled in the art. Additionally, or alternatively, the sensing circuitry  48  may comprise an engine-trip or shut-down circuit to shut down the combustion turbine  24  in response to detection of a particular contaminating material or particular amount thereof.  
         [0032]    The sensing circuitry  48  also illustratively comprises a data analyzer  58  connected directly or through the data logger  56  to the reader  54 . As with both the reader  54  and the data logger  56 , the data analyzer  58  may be a discrete circuit for performing a specific analysis. Alternatively, however, the data analyzer  58  may be hardware and/or software associated with a general-purpose, programmable computer.  
         [0033]    Accordingly, the sensing circuitry  48  can read signals and record data derived from the sampled air drawn from the inlet air flow  41 . The data can be analyzed, trends extracted therefrom, and assessments made as to whether and to what extent contaminating materials are reaching the air inlet  40  of the combustion turbine  24 . Decisions can then be made as to what, if any, corrective steps need to be taken. Moreover, such analyses can be performed substantially continuously and in near real-time without taking a sample to a laboratory and waiting for the return of results before making any further calculations.  
         [0034]    To efficiently acquire the sampled air from the inlet air flow  41 , the apparatus  20  illustratively includes a sampling probe  60 . The sampling probe  60  is connected to be in fluid communication with and between the inlet air flow  41  and the solution container  46  to thereby convey the sampled air to the solution  50  contained therein. So that the above-described analyses and determinations can be made as desired and without interruption to the operation of the combustion turbine  24 , the sampling probe  60  can sample the inlet air flow  41  during operation of the combustion turbine  24 .  
         [0035]    In the embodiment shown in FIG. 2, the sampling probe  60  is illustratively an isokinetic sampling probe. The sampling probe  60  thus measures the velocity of the inlet air flow and, illustratively using the flow controller  62 , adjusts the rate at which sampled air is drawn from the inlet air flow. Sampled air is illustratively drawn through a tube  64  and into the solution container  46  where it passes through the solution  50  before exiting the solution container under the control of the flow controller  62 . The sampling probe  60 , by controlling the flow of the sampled air based on the velocity of the inlet air flow  41 , thus helps ensure that the sample drawn gives an accurate representation of the material that may be contained in the inlet air flow, as will be readily understood by those skilled in the art.  
         [0036]    Positioned downstream from the filter  44 , the sampling probe  60  provides a sample from which some material or particulates have already been extracted. This yields, therefore, a sample that likely reflects the concentration of materials or particulates in the inlet air flow  41  carried to the air inlet  40  of the combustion turbine  24 .  
         [0037]    An additional aspect of the invention relates to a method for sampling an inlet air flow  41  for a combustion turbine  24 . Referring to the flow diagram  70  of FIG. 3, the method comprises providing a sampling probe  60  for acquiring sampled air from the inlet air flow  41  (Block  74 ) after the start at Block  72 . At Block  76 , the sampled air from the inlet air flow is passed into a solution  50 , and materials from the sampled air are dissolved in the solution. The solution  50 , at Block  78 , is sensed for at least one dissolved material using sensing circuitry  48 .  
         [0038]    Data based on the sensing is logged at Block  80 , and the data is analyzed at Block  82 . Based on the analysis of the logged data, a determination is made as to whether corrective action is needed (Block  84 ). The corrective action may, for example, entail replacing the filter  44  used to prevent salt and/or other contaminant materials from entering the combustion turbine  24 . Replacement may be required if, for example, the filter  44  has become so saturated that if is not effectively filtering contaminate material from the inlet air flow  41  any longer.  
         [0039]    If no corrective action is needed, then the sampling probe  60  continues to sample the inlet air flow  41  while the combustion turbine  24  is operated. Based on the analysis of the logged data, however, it may be determined that some corrective action is needed. If so, a determination is made whether near-term action is needed (Block  86 ). If near-term action is not needed, then, based on the logged data, a date for when the action will be needed is estimated, and the action is appropriately scheduled (Block  90 ). Otherwise, the corrective action (e.g., replacement of filter  44 ) is taken at Block  88 .  
         [0040]    Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.