Abstract:
Systems and methods for de-icing an inlet screen and dehumidifying an inlet air filter in a gas turbine engine are disclosed herein. In one embodiment, a method may include determining a current inlet screen temperature. The method also may include determining a desired inlet screen temperature. If the current inlet screen temperature is less than the desired inlet screen temperature, the method may further include determining a first amount of gas turbine compartment ventilation discharge air necessary to achieve the desired inlet screen temperature, extracting the first amount of gas turbine compartment ventilation discharge air, and conveying the first amount of gas turbine compartment ventilation discharge air to the inlet screen.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The disclosure relates generally to gas turbine engines and more particularly relates to systems and methods for de-icing inlet screens and dehumidifying inlet air filters for gas turbine engines. 
       BACKGROUND 
       [0002]    Gas turbine engines are utilized globally for electric power generation or as mechanical drives for operating equipment under a variety of climatic conditions. Operation during cold ambient temperature and high humidity conditions often causes ice to build up on the inlet filter house components. Frequently, this ice build-up on air filtration elements (e.g., bird screens, moisture separators, coalescer filters, or filtration modules) is severe enough to restrict air flow and to increase the inlet air pressure drop across the filter house, thus leading to performance loss or even shut down. Precipitating icing forms when water ingested as liquid or solid at a temperature near or below freezing (e.g., wet snow, freezing rain, etc.) adheres to most exposed surfaces, causing ice buildup. Also, ice formation occurs when saturated cooled air comes in contact with colder filter house surfaces. 
       SUMMARY 
       [0003]    Some or all of the above needs and/or problems may be addressed by certain embodiments of the disclosure. The disclosure provides systems and methods for de-icing an inlet screen and dehumidifying an inlet air filter in a gas turbine engine. In one embodiment, a method for de-icing an inlet screen and dehumidifying an inlet air filter in a gas turbine engine may include determining a current inlet screen temperature. The method also may include determining a desired inlet screen temperature. If the current inlet screen temperature is less than the desired inlet screen temperature, the method may further include determining a first amount of gas turbine compartment ventilation discharge air necessary to achieve the desired inlet screen temperature, extracting the first amount of gas turbine compartment ventilation discharge air, and conveying the first amount of gas turbine compartment ventilation discharge air to the inlet screen. 
         [0004]    In another embodiment, the disclosure provides a system for de-icing an inlet screen and dehumidifying an inlet air filter in a gas turbine engine. The system may include a gas turbine engine, a gas turbine compartment disposed about the gas turbine engine, an inlet screen configured to provide air to the gas turbine engine, a manifold coupled to the inlet screen, and a first conduit fluidly coupling the gas turbine compartment and the manifold. 
         [0005]    In yet another embodiment, the disclosure provides a system for de-icing an inlet screen and dehumidifying an inlet air filter in a gas turbine engine. The system may include a compressor, a combustor in communication with the compressor, and a turbine in communication with the combustor. The system also includes a gas turbine compartment disposed about the compressor, the combustor, and the turbine. Moreover, the system includes an inlet screen configured to provide air to the compressor, a manifold coupled to the inlet screen, and a first conduit fluidly coupling the gas turbine compartment and the manifold. 
         [0006]    These and other embodiments, aspects, and features of the disclosure will become apparent to those skilled in the art from the following detailed description, the accompanying drawings, and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale. 
           [0008]      FIG. 1  is a schematic view of a system according to one or more embodiments. 
           [0009]      FIG. 2  is a schematic view of a system according to one or more embodiments. 
           [0010]      FIG. 3  is a schematic of an embodiment of a control system according to one or more embodiments. 
           [0011]      FIG. 4  is a flow chart illustrating a method according to one or more embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Referring now to the drawings, in which like numerals refer to like elements throughout the several views,  FIG. 1  is an example embodiment of a system  100  for de-icing a gas turbine engine inlet screen and dehumidifying inlet air filters. The system  100  may include one or more gas turbine engines  102 . Each gas turbine engine  102  may include a compressor  104 , a combustor  106 , and a turbine  108 . The compressor  104  may compress an incoming flow of air. The compressor  104  may deliver the compressed flow of air to the combustor  106 , where the compressed flow of air mixes with a compressed flow of fuel. The air/fuel mixture may be ignited to create a flow of combustion gases. The flow of combustion gases may be delivered to the turbine  108 . The flow of combustion gases may drive the turbine  108  to produce mechanical work. The mechanical work produced in the turbine  108  may drive the compressor  104  and an external load, such as an electrical generator or the like. The flow of combustion gases may be exhausted via an exhaust subsystem  110  or the like to a stack or otherwise disposed. 
         [0013]    The gas turbine engine  102  may use natural gas, various types of syngas, and/or other types of fuels. The gas turbine engine  102  may be anyone of a number of different gas turbine engines such as those offered by General Electric Company of Schenectady, N.Y. and the like. The gas turbine engine  102  may have different configurations and may use other types of components. Other types of gas turbine engines also may be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment also may be used herein together. 
         [0014]    The gas turbine engine  102  may include an inlet screen  112  or filter house that includes one or more filter assemblies having a number of inlet air filters  114  that remove moisture and/or particulate matter (such as dust and/or debris) from intake air  116  channeled to the gas turbine engine  102 . In some instances, a manifold  118  may be coupled to the inlet screen  112 . The manifold  118  may be configured to de-ice the inlet screen  112  and/or dehumidify the inlet air filters  114 . 
         [0015]    The gas turbine engine  102  may be wholly or partially enclosed by a gas turbine compartment  120 . During operation of the gas turbine engine  102 , waste heat may be released into the gas turbine compartment  120 , which in turn may heat the air within the gas turbine compartment  120 . The system  100  utilizes the waste heat from the gas turbine compartment  120  for de-icing the inlet screen  112  and/or dehumidifying inlet air filters  114 . For example, a first conduit  122  may fluidly couple the gas turbine compartment  120  with the manifold  118 . In this manner, the heated air from the gas turbine compartment  120  may be used to de-ice the inlet screen  112  and/or dehumidifying inlet air filters  114 . For example, a first control valve  124  may be disposed about the first conduit  122 . The first control valve  124  may be adjusted to provide a first amount of gas turbine compartment ventilation discharge air necessary to achieve a desired inlet screen temperature. The desired inlet screen temperature may be sufficient to de-ice the inlet screen  112 . In addition, the desired inlet temperature may be sufficient to de-humidify the inlet air filter  114 . 
         [0016]    In some instances, a second conduit  126  may fluidly couple the gas turbine compartment  120  with the surrounding atmosphere. In this manner, excess gas turbine compartment ventilation discharge air may be vented to the atmosphere or elsewhere. For example, a second control valve  128  may be disposed about the second conduit  126 . The second control valve  128  may be adjusted to discharge a portion of the gas turbine compartment ventilation discharge air to the atmosphere. 
         [0017]    The gas turbine compartment ventilation discharge air may be extracted from the gas turbine compartment  120  by at least one extraction blower  130  (or exhaust fan) disposed about the first conduit  122  and/or the second conduit  126 . That is, the extraction blower  130  may draw the heated air out of the gas turbine compartment  120 . In some instances, the heated air from the gas turbine compartment  120  may be supplied to the manifold  118  to de-ice the inlet screen  112  and/or dehumidifying the inlet air filters  114 . In other instances, the heated air from the gas turbine compartment  120  may be discharged to the atmosphere. 
         [0018]    In some instances, additional sources of waste heat may be used in conjunction with or alternative to the waste heat from the gas turbine compartment  120  to de-ice the inlet screen  112  and/or dehumidifying inlet air filters  114 . For example, as depicted in  FIG. 2 , waste heat (such as heated air) from an air cooled generator  132  and/or switchgear compartments  134  may be used. In some instances, one or more conduits  136  may fluidly couple the manifold  118  with the gas turbine compartment  120 , the air cooled generator  132 , and/or switchgear compartment  134 . In addition, the extraction blower  130  may draw the heated air out of the gas turbine compartment  120 , the air cooled generator  132 , and/or switchgear compartment  134 . Moreover, one or move control valves (not shown) may be disposed about the one or more conduits  136  to control the flow or combination of flows therein. 
         [0019]    As depicted in  FIG. 3 , the position of the first control valve  124  and/or the second control valve  128  may be controlled by a controller  136 . The controller  136  also may control the extraction blower  130 . Moreover, the controller  136  may receive inputs from one or more sensors disposed about the first conduit  122 , the second conduit  126 , the inlet screen  112 , the inlet air filters  114 , among others. The controller  136  may be configured to activate one or more actuators. The controller  136  may be an independent controller or integrated with a gas turbine control system. The controller  136  may include at least a memory and one or more processing units (or processor(s)). The processor(s) may be implemented as appropriate in hardware, software, firmware, or combinations thereof. Software or firmware implementations of the processor(s) may include computer-executable or machine-executable instructions written in any suitable programming language to perform the various functions described herein. Moreover, the processor may be associated with a network, a server, a computer, or a mobile device. 
         [0020]      FIG. 4  is a flow chart illustrating a method  400  for de-icing the inlet screen and/or dehumidifying the inlet air filter according to one or more embodiments of the disclosure. At block  402 , a current inlet screen temperature may be determined. For example, one or more sensors may be disposed about the inlet screen  112  and/or the inlet air filters  114 . The sensors may be in communication with the controller  136 . At block  404 , a desired inlet screen temperature may be determined. For example, the desired inlet screen temperature may be sufficient to de-ice the inlet screen  112  and/or to de-humidify the inlet air filter  114 . At block  406 , if the current inlet screen temperature is less than the desired inlet screen temperature, then the method  400  proceeds to block  408 . If not, then the method ends at block  410 . 
         [0021]    At block  408 , a first amount of gas turbine compartment ventilation discharge air necessary to achieve the desired inlet screen temperature may be determined. Next, at block  412 , the first amount of gas turbine compartment ventilation discharge air may be extracted from the gas turbine compartment. For example, the extraction blower  130  may draw the heated air out of the gas turbine compartment  120 . The first amount of gas turbine compartment ventilation discharge air may then be conveyed to the inlet screen at block  414 . For example, the first control valve  124  may be adjusted to provide the first amount of gas turbine compartment ventilation discharge air necessary to achieve the desired inlet screen temperature. 
         [0022]    It should be apparent that the foregoing relates only to certain embodiments of the present application and that numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the disclosure as defined by the following claims and the equivalents thereof.