Abstract:
A gas turbine includes a compressor with a plurality of pressure plates, a combuster downstream from the compressor, and a turbine downstream from the combustor and axially aligned with the compressor. The combustor produces combustion gases that flow to the turbine. A first manifold connected to the combustor contains a first process gas for combustion in the combustor. A second manifold connected upstream of the turbine contains a second process gas, and a portion of the second process gas flows to the plurality of pressure plates.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally involves a Brayton cycle gas turbine. More particularly, the present invention relates to a gas turbine that operates using process gases. 
       BACKGROUND OF THE INVENTION 
       [0002]    Gas turbines are widely used in commercial operations for power generation.  FIG. 1  illustrates a typical gas turbine  10  known in the art. As shown in  FIG. 1 , the gas turbine  10  generally includes a compressor  12  at the front, one or more combustors  14  around the middle, and a turbine  16  at the rear. The compressor  12  and the turbine  16  typically share a common rotor  18 . 
         [0003]    The compressor  12  includes multiple stages of compressor blades  20  attached to the rotor  18 . Ambient air, as a working fluid, enters an inlet  22  of the compressor  12 , and rotation of the compressor blades  20  progressively compresses the working fluid. Some of the compressed working fluid is extracted from the compressor  12  through extraction plots  23  for other use, and the remainder of the working fluid exits the compressor  12  and flows to the combustors  14 . 
         [0004]    The working fluid mixes with fuel in the combustors  14 , and the mixture ignites to generate combustion gases having a high temperature, pressure, and velocity. The combustion gases exit the combustors  14  and flow to the turbine  16  where they expand to produce work. 
         [0005]    Compression of the ambient air in the compressor  12  produces an axial force on the rotor  18  in a forward direction, toward the compressor inlet  22 . Expansion of the combustion gases in the turbine  16  produces an axial force on the rotor  18  in an aft direction, toward the turbine exhaust  24 . A thrust bearing  26  at the front of the gas turbine  10  holds the rotor  18  in place and prevents axial movement of the rotor  18 . To reduce the net axial thrust on the rotor  18 , and thus the size and associated cost of the thrust bearing  26 , the gas turbine  10  is typically designed so that the axial forces generated by the compressor  12  and the turbine  16  are approximately equal but opposite. 
         [0006]    Various commercial processes generate effluent process gases. For example, chemical processes at oil fields generate substantial quantities of pressurized oxygen, carbon dioxide, or nitrogen as effluent process gases. The effluent process gases are transferred for storage and/or ultimate disposal. 
         [0007]    The costs associated with the collection, storage, and disposal of the process gases may be considerable, and various attempts have been made to operate a gas turbine system using process gases. However, the process gases have different molecular weights, compressibility, flammability, and other physical characteristics than ambient air, for which the gas turbine is designed. Therefore, the need exists for a gas turbine that can operate using effluent process gases created by commercial operations. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0008]    Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
         [0009]    One embodiment of the present invention is a gas turbine that includes a compressor with a plurality of pressure plates, at least one combustor downstream from the compressor, and a turbine downstream from the at least one combustor and axially aligned with the compressor. The combustor produces combustion gases that flow to the turbine. A first manifold is connected to the combustor, and the first manifold contains a first process gas for combustion in the combustor. A second manifold is connected upstream of the turbine, and the second manifold contains a second process gas. A portion of the second process gas flows to the pressure plates. 
         [0010]    In an alternate embodiment, a gas turbine includes a compressor with a plurality of pressure plates, at least one combustor downstream from the compressor, and a turbine downstream from the combustor and axially aligned with the compressor. The combustor produces combustion gases that flow to the turbine. A first manifold is connected to the gas turbine upstream of the turbine, and the first manifold contains a first process gas for combustion in the combustor. A second manifold is connected upstream of the turbine, and the second manifold contains a second process gas. A portion of the second process gas flows to the pressure plates. 
         [0011]    The present invention also includes a method for operating a gas turbine that has a compressor, a plurality of combustors, and a turbine. The method includes removing compressor blades from the compressor and installing a plurality of pressure plates in the compressor. The method further includes supplying a first process gas to the gas turbine upstream of the turbine and combusting the first process gas in at least one of the combustors. In addition, the method includes supplying a second process gas to the gas turbine upstream of the turbine and directing at least a portion of the second process gas to the pressure plates. 
         [0012]    Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which: 
           [0014]      FIG. 1  is a plan drawing of a typical gas turbine known in the art; 
           [0015]      FIG. 2  is a simplified diagram of a conventional piping arrangement for storing and transferring effluent process gases; and 
           [0016]      FIG. 3  is a plan view of a gas turbine according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. 
         [0018]    Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0019]      FIG. 2  provides a simplified diagram of a typical piping and storage system  28  for effluent process gases generated by a commercial system. As shown in  FIG. 2 , the effluent process gases may be transferred to one or more containers  30  for subsequent use or transfer. The containers  30  may be any receptacle for holding the effluent process gases, such as drums, bladders, vats, tanks, reservoirs, and other structures known to one of skill in the art for holding a fluid. 
         [0020]    Various means are known in the art for transferring the effluent process gases to and from the containers  30 . For example, as shown in  FIG. 2 , a conventional piping and valve arrangement  32  may provide fluid communication between the commercial process, the containers  30 , and the ultimate disposal process for the process gases. One or more booster pumps  34 , pressurized air, or even gravity may be used to transfer the effluent process gases between locations. Alternatively, the effluent process gases may be collected and stored at one location in containers, and the containers may be shipped by road, rail, air, or water to another location for continued storage or ultimate disposal. 
         [0021]      FIG. 3  provides a plan view of a gas turbine  40  according to an embodiment of the present invention. As shown in  FIG. 3 , the gas turbine  40  nominally includes a compressor  42  at the front, one or more combustors  44  around the middle, and a turbine  46  at the rear. A rotor  48  connects and axially aligns the compressor  42  and the turbine  46 . A thrust bearing  50  at the front of the gas turbine  40  holds the rotor  48  in place and prevents axial movement of the rotor  48 . Although  FIG. 3  illustrates the thrust bearing  50  at the front of the gas turbine  40 , the thrust bearing  50  may be located at any position along the rotor  48 . 
         [0022]    The compressor  42  has been modified from the prior art compressor previously described with respect to  FIG. 1 . Specifically, the compressor blades present in the typical compressor have been removed and replaced with one or more pressure plates  52 . The pressure plates  52  are defined to include any surface that substantially prevents or restricts the flow of gases or fluids past the pressure plates  52  in either direction. The pressure plates  52  may rotate with the rotor  48  or may be stationary with respect to the rotor  48 . 
         [0023]    The combustors  44  are arranged around the gas turbine  40  between the compressor  42  and the turbine  46 . A casing  54  surrounds the combustors  44  and provides a sealed enclosure around the combustors  44 . The combustors  44  produce combustion gases that flow to the turbine  46 . 
         [0024]    The turbine  46  is axially aligned with the compressor  42 . The combustion gases from the combustors  44  expand in the turbine  46  to produce work. Expansion of the combustion gases in the turbine  46  produces an axial force on the rotor  48  in an aft direction, toward the turbine exhaust  56 . 
         [0025]    A first manifold  58  containing a first process gas connects to the gas turbine  40  at any point upstream of the turbine  46 . As shown in  FIG. 3 , branch lines  60  may provide a fluid communication for the flow of the first process gas from the first manifold  58  directly to the combustors  44 . The first process gas may be oxygen or any other oxygen containing process gas for combustion in the combustors  44 . 
         [0026]    A second manifold  62  containing a second process gas similarly surrounds the gas turbine  40  upstream of the turbine  46 . Branch lines  64  provide a fluid communication for the flow of the second process gas from the second manifold  64  to the gas turbine  40 . The second process gas may be carbon dioxide, nitrogen, or any other diluent for mixing with the first process gas. 
         [0027]    The second process gas flows around the combustors  44  and away from the turbine  46 . A portion of the second process gas flows to the pressure plates  52  in the compressor  42 . The pressure of the second process gas against the pressure plates  52  produces an axial force on the rotor  48  in a forward direction, toward the compressor inlet  66 . The axial force on the rotor  48  in the compressor  42  is thus in the opposite direction as the axial force on the rotor  48  in the turbine  46 , reducing the net axial thrust on the rotor  48  and thus the size and associated cost of the thrust bearing  50 . The temperature of the second process gas may heat the pressure plates  52  and rotor  48 . As a result, a third process gas may be supplied to the compressor  42  to cool the pressure plates  54  and rotor  48 . The third process gas may be supplied to the compressor  42  through extraction ports  68  that already exist on the compressor  42 . The third process gas may be any available gas having a suitable temperature for cooling the pressure plates  52  and rotor  48 . The third process gas may even be the same as the second process gas, except having a lower temperature than the second process gas. 
         [0028]    The remainder of the second process gas mixes with the first process gas in the combustors  44 . The mixture of the first and second process gases ignite to produce the combustion gases having a high temperature, pressure, and velocity. The combustion gases exit the combustors  44  and flow to the turbine  46 . As previously described, the expansion of the combustion gases in the turbine  46  produce work and an axial force on the rotor  48  in the aft direction, toward the turbine exhaust  56 . 
         [0029]    Embodiments of the present invention may also provide a method for operating an existing gas turbine  40  to use process gases, as shown in  FIG. 3 . As shown in  FIG. 3 , the gas turbine  40  nominally includes a compressor  42 , one or more combustors  44 , and a turbine  46 , as is known in the art. 
         [0030]    The compressor  42  is modified by removing the compressor blades, and one or more pressure plates  52  are installed in place of the compressor blades in the compressor  42 . 
         [0031]    A first manifold  58  supplies a first process gas to the gas turbine  40  upstream of the turbine  56 , and the combustors  52  ignite the first process gas. A second manifold  62  supplies a second process gas to the gas turbine  40  upstream of the turbine  60 . At least a portion of the second process gas flows to the pressure plates  52 . The process gases may be any effluent process gas produced from another commercial system, as previously described. 
         [0032]    The compressor  42  may be further modified by supplying a third process gas to one or more of the pressure plates  52  for cooling. The third process gas may be any available gas having a suitable temperature for cooling the pressure plates  52  and rotor  48 . The third process gas may even be the same gas as the second process gas, except having a lower temperature than the second process gas. 
         [0033]    It should be appreciated by those skilled in the art that modifications and variations can be made to the embodiments of the invention set forth herein without departing from the scope and spirit of the invention as set forth in the appended claims and their equivalents.