CH702376A2 - Geothermal heat exchanger system for use in a gas turbine power plant. - Google Patents

Abstract

A geothermal heat exchange system for use in a gas turbine power plant that includes an inlet chamber (112) that directs airflow to a compressor (52) that compresses the airflow that is subsequently mixed with a fuel in a combustor (56) and burned, such that the resulting hot gas flow is passed through a turbine (54), the earth heat exchanger system comprising: means for exchanging heat (136) between a ground (134) and the airflow passing through the inlet chamber (112).

Description

BACKGROUND TO THE INVENTION

The present application relates generally to gas turbines and related apparatus, systems and methods. In particular, but not by way of limitation, the present application relates to devices, systems and methods for improving the energy efficiency of gas turbines by utilizing, among other things, geothermal energy.

With increasing energy costs and increasing demand, the goal is to improve the efficiency of gas turbines and renewable energy sources, such as geothermal energy or geothermal, to use more effectively, of importance. Toward this end, as described below, cost-effective systems can be developed to utilize the relatively constant temperature found beneath the surface of the earth to improve gas turbine operation, particularly when operating on hot and cold days.

As will be understood by one skilled in the art, the performance of gas turbines may be adversely affected if ambient temperatures are either too hot or too cold. If e.g. If the intake air temperature is too hot, the heat consumption of the gas turbine increases and the output power decreases, which of course reduces the efficiency of the system. On the other hand, if the ambient temperatures fall below a certain level, icing may occur. This can e.g. at the inlet to the compressor, at the inlet to the filter housing or the inlet guide vanes or other similarly arranged components. The icing can damage the equipment or make it ineffective. For example, For example, icing may prevent the inlet guide vanes from operating properly, which may adversely affect the efficiency of the turbine.

To solve these problems, conventional systems have been proposed. For example, Some conventional systems for hot day operation propose the use of a mechanical cooling system to cool the air entering the compressor. This option is undesirable because the energy required to operate the radiator significantly affects the overall efficiency of the gas turbine as well as the high equipment costs associated with the radiator. Another conventional system is an inlet water misting system that includes feeding water vapor into the air entering the compressor. The evaporation of the injected steam reduces the temperature of the air flow. However, proper operation of a system of this type will still depend at least somewhat on environmental conditions and will require the installation of expensive components and control systems. Furthermore, the addition of water to the flow path of the plant in this way can cause faster deterioration and erosion of parts in the flow path, and generally increases the maintenance cost.

For cold day operation, conventional systems generally involve extracting energy from the plant exhaust gas to raise the temperature of the air entering the compressor. Such systems, in turn, require installation of expensive components and control systems. Further, in the mass in which the energy in the exhaust gas is reduced for other purposes, e.g. As the heat source in the steam turbine of a combined cycle power plant may be used, the diversion of a portion of the exhaust energy may generally be the overall efficiency of the power plant.

As a result, there remains a need for improved apparatus, systems, and methods for cost-effectively mitigating performance-related problems in gas turbines that occur during hot and cold day operation.

BRIEF DESCRIPTION OF THE INVENTION

The present application thus describes a geothermal heat exchange system for use in a gas turbine power plant, which includes an inlet chamber (also referred to as inlet plenum) which directs air flow to a compressor which compresses the air flow, the compressed air flow subsequently being in a combustion chamber Fuel is mixed and burned, so that the resulting hot gas flow is passed through a turbine. The geothermal heat exchange system may include means for exchanging heat between a soil and the airflow passing through the inlet chamber.

In some embodiments, the means for exchanging heat between the earth and the airflow passing through the inlet chamber comprises a heat pipe. In some embodiments, the means for exchanging heat between the earth and the airflow passing through the inlet chamber comprises either a heat sink or a thermosyphon.

In some embodiments, the means for exchanging heat between the earth and the air flow moving through the inlet chamber comprises a heat transfer fluid which is circulated by a pump through a circuit passing through the earth and the inlet chamber.

In some embodiments, the earth either has a position below the surface of the ground or a position below the surface of a body of water. In some embodiments, the earth has a position at a predetermined depth below the surface of the ground. The predetermined depth has a depth that is greater than 25 feet.

In some embodiments, the heat pipe comprises a two-phase heat transfer device that includes a sealed tube made of a material having high thermal conductivity. In some embodiments, the sealed tube is evacuated and filled with a small amount of working fluid.

In some embodiments, the heat pipe is substantially vertically aligned and has a wick structure, the wick structure having a material configured to achieve a desired capillary pressure on the condensed working fluid. In some embodiments, the wick structure has either a groove wick structure, a wire mesh wick structure, a powder metal wick structure, or a fiber / spring wick structure. In some embodiments, the heat pipe is configured to transfer heat from the airflow through the inlet chamber to the earth on hot days so that the efficiency of the gas turbine power plant is increased. In some embodiments, the heat pipe is configured to transfer heat from the earth to the airflow through the inlet chamber on cold days, thereby avoiding undesirable ice formation.

In some embodiments, the geothermal heat exchanger system further includes means for transferring heat between exhaust flow from the turbine and the inlet chamber. In some embodiments, the means for transferring heat between the exhaust gas flow from the turbine and the inlet chamber comprises a heat pipe.

These and other features of the present application will become apparent upon review of the following detailed description of the preferred embodiments, taken in conjunction with the drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a sectional view of a gas turbine typical of turbine types that may be used in power plants in which embodiments according to the present invention may be used;

Fig. 2 illustrates a schematic representation of a gas turbine engine, the representation of which is used to illustrate power plants in accordance with embodiments of the present invention;

FIG. 3 is a schematic diagram illustrating the configuration of a gas turbine power plant according to an exemplary embodiment of the present application; FIG.

Fig. 4 is a schematic illustration showing a front view (i.e., looking into the mouth of the inlet chamber) of the configuration of heat pipes in the inlet chamber according to an exemplary embodiment of the present application; and

Fig. 5 is a schematic illustration showing the configuration of a gas turbine power plant according to an alternative embodiment of the present application.

DETAILED DESCRIPTION OF THE INVENTION

Illustrative embodiments of the invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are illustrated. In fact, the invention may 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 meets the applicable statutory provisions. Like reference numerals designate like elements throughout.

In order to clearly describe the invention according to the present application, it may be necessary to select a terminology that relates to and describes particular machine components or parts of a turbine engine or turbine system. Whenever possible, industry-standard terminology is used and used in a manner consistent with its accepted meaning. However, all such terminology is intended to be broadly understood and not construed narrowly, so that the meaning and scope of the appended claims intended herein are not unduly limited. Those skilled in the art will understand that often certain components may be referred to by several different names. Moreover, what is described herein as a single part may include multiple component parts and be referred to in other contexts as including multiple component parts, or what may be described herein as containing multiple component parts, in the form of a single part and in FIG Some cases may be referred to as one item. As such, understanding the scope of the invention described herein should be taken not only to the specified terminology and description, but also to the structure, configuration, function and / or use of the component as provided herein.

In addition, some descriptive terms may be used herein. The meaning for these terms is intended to include the following definitions. As used herein, "downstream" and "upstream" are terms indicating a direction relative to a flow of a working fluid through the turbine. As such, the term "downstream" means the direction of the flow, and the term "upstream" means in the opposite direction to the flow through the turbine. Related to these terms, the terms "rear (r, s)" and / or "trailing edge" refer to the downstream direction, the downstream end, and / or in the direction of the downstream end of the described component. Further, the terms "front (r, s)" or "leading edge" refer to the upstream direction, the upstream end, and / or in the direction of the upstream end of the described component. The term "radial" refers to a movement or position perpendicular to an axis. It is often necessary to describe parts that are at different radial positions with respect to an axis. In this case, if a first component is closer to the axis than a second component, it may be stated herein that the first component is "inboard" or "radially inward" from the second component. On the other hand, if the first component is farther from the axis than the second component, it may be stated herein that the first component is "outboard" or "radially outward" from the second component. The term "axial" refers to a movement or position parallel to an axis. Further, the term "circumferential" or "circumferential" refers to a movement or position about an axis.

Referring now to the drawings, Fig. 1 is an illustration of a conventional gas turbine engine 50. Generally, gas turbine engines operate by extracting energy from pressurized hot gas flow generated by combustion of a fuel in a stream of compressed air becomes. As illustrated in FIG. 1, the gas turbine engine 50 may be configured with an axial compressor 52 mechanically coupled to a downstream turbine section or turbine 54 via a common shaft or rotor and a combustion chamber 56 connected between the compressor 52 and the compressor Turbine 54 is arranged.

The compressor 52 may include a plurality of stages, each stage having a row of compressor rotor blades followed by a row of compressor stator blades. In particular, one stage generally includes a row of compressor rotor blades rotating about a central shaft followed by a row of compressor stator blades which remain stationary during operation. The compressor stator blades are generally spaced apart circumferentially and fixed about the axis of rotation. The compressor rotor blades are attached to the shaft so that as the shaft rotates during operation, the compressor rotor blades rotate therealong. As will be understood by those skilled in the art, the compressor rotor blades are configured to impart kinetic energy when circulating on the shaft of the air or fluid flowing through the compressor 52. The turbine 54 may also include multiple stages. A turbine stage may include a plurality of turbine blades or turbine rotor blades that revolve on the shaft during operation and a plurality of stator blades or turbine stator blades that remain stationary during operation. The turbine stator blades are generally circumferentially spaced from each other and fixed about the axis of rotation. On the other hand, the turbine rotor blades may be mounted on a turbine wheel for rotation on the shaft.

In use, an air flow is compressed by the rotation of the compressor rotor blades 60 in the axial compressor 52. In the combustion chamber 56, energy is released when the compressed air is mixed with a fuel and ignited. The resulting flow of pressurized hot gases from the combustor 56, commonly referred to as the plant fluid, is then expanded as it passes through the turbine rotor blade. The flow of the working fluid causes rotation of the turbine rotor blade on the shaft. Thereby, the energy of the fuel is converted into the kinetic energy of the flow of the working fluid, which is then converted into the mechanical energy of the rotating blades and the connection between the rotor blades and the shaft of the rotating shaft. The mechanical energy of the shaft can then be used to drive the rotational movement of the compressor rotor blades to produce the necessary supply of compressed air, and also, e.g. for driving a generator (not shown) to generate electricity.

Fig. 2 illustrates a schematic representation of a gas turbine engine 100, the representation of which is used to illustrate power plants according to embodiments of the present invention. As illustrated, the gas turbine engine 100 may include a compressor 52, a combustor 56, and a turbine 54. At the upstream end of the compressor 52, an inlet chamber or inlet plenum 112 may be disposed. The inlet chamber 112 essentially provides a passage through which an air supply to the compressor 52 is introduced. It will be understood that the configuration of the inlet chamber 112 may have many different configurations. As illustrated, the inlet chamber may be configured to have a relatively wide intersection, the cross-section of which decreases to a channel that directs air supply to the inlet of the compressor 52. Of course, in some gas turbine applications, a significantly smaller structure may be used to provide an inlet for the air entering the compressor 52. As such, by inlet chamber 112 as used herein is meant any structure, large or small, positioned upstream of one of the stages of compressor 52 and through which at least a portion of the air entering compressor 52 flows. As will be understood by those skilled in the art, the inlet chamber 112 may include certain components, such as filters, mufflers, etc., that enhance their function. However, since these components are not strictly necessary or exclusive for the operation of a power plant according to the present invention, they have been omitted in the figures. As will become apparent, the flexibility of embodiments of the present invention enables them to be included in a variety of manners in substantially any type of structure of an inlet chamber 112 or directly within the compressor 52 itself.

FIG. 3 is a schematic diagram illustrating the configuration of a gas turbine power plant 130 according to an embodiment of the present application. Similar to the system illustrated in FIG. 2, the gas turbine power plant 130 may include a compressor 52, a combustor 56, a turbine 54, and an inlet chamber 112. According to the present invention, the gas turbine power plant 130 may further include a heat exchange device that provides for the exchange of energy between the air flow in the inlet chamber 112 or through the compressor 52 and the ground or ground 134. As used herein, "earth" or "ground" is meant to include any type of geothermal medium. In some embodiments, soil refers to the soil at a predetermined subsurface level, as illustrated in FIG. As can be appreciated, the temperature of the earth below the surface of the soil remains fairly constant regardless of the season. This is especially true at depths between about 25 and 500 feet below the surface of the earth. In some embodiments, lesser depths may also be used; e.g. For some applications, depths between about 10 and 50 feet below the surface of the earth may be suitable.

These relatively constant subterranean temperatures mean that the Earth's temperature within these given depth ranges remains relatively cool throughout the year, even in hot climates. For example, Atlanta, Georgia's ground temperature remains fairly constant at 62 ° F throughout the year. At the other end of the spectrum, in regions with relatively cold climates, soil and ground temperatures remain relatively warm, even in the coldest months of the year. For example, The floor temperature of New York, New York, remains fairly constant at 52 ° F throughout the year. As noted, the terms "ground" or "earth" may refer to other types of geothermal media, such as a subsurface site in a body of water, such as a lake or river, or the sea.

As illustrated in FIG. 3, in a preferred embodiment, the heat exchange device may be in the form of one or more elongated heat transfer structures 136, such as one or more tubes extending from a location in the earth (eg, one or more tubes) Location in the ground below ground, may be a sub-surface location in a lake or other such location) to a location within the inlet chamber 112. The heat transfer structures 136 may be configured to efficiently transfer heat from a hot side (which may be either the earth or the inlet chamber, depending on the application as well as the current ambient and ground temperature conditions) to a cold side (depending on the application as well as the current ambient and ground temperature conditions, either the earth or the inlet chamber may be). On the hot side and the cold side, the structure 136 generally includes an outer surface that conducts heat well, such as a metallic surface. In addition, one end of the structure 136, which as illustrated may be a tube, may be positioned in the soil at a desired depth so as to contact the surrounding soil or water and heat transfer between the surrounding material and the structure 136 as desired. The other end of the structure or tube 136 may be positioned in the inlet chamber 112 such that the air flowing through the inlet chamber 112 flows over and around it so that the heat transfer occurring between the structure 136 and the air flow occurs at a desired rate ,

In some embodiments, the elongated structure 136 of FIG. 3 may comprise a conventional heat pipe. A heat pipe is a two-phase heat transfer device with a very effective thermal conductivity. A heat pipe generally consists of a sealed pipe or sleeve made of a material of high thermal conductivity, such as steel, copper or aluminum, at both the hot and cold ends. It may be cylindrical or planar, and the inner surface may be lined with a capillary wick as discussed below. During construction, the heat pipe is deflated and filled with a small amount of a working fluid, for example water, acetone, nitrogen, methanol, ammonia or sodium. Other types of inorganic materials may be used. In the evaporator area, heat is absorbed by evaporation of the working fluid. The steam transports the heat to the condenser area, where the steam condenses, thereby giving off heat to a cooling medium.

In some embodiments, the heat pipe according to the present invention may comprise a heat pipe closed in a loop, i. a heat pipe having a wick structure exerting capillary pressure on the liquid phase of the working fluid. The wick structure may include any material that is capable of exerting sufficient capillary pressure on the condensed liquid to wick it back to the heated end. In some embodiments, the wick structure may be one of the common wick structures used in conventional heat pipe applications, including a groove-like wick structure (ie, a series of grooves extending longitudinally along the inner surface of the heat pipe), a wire mesh, or caterpillar-like wick structure. a powder metal wick structure and a fiber / spring wick structure. The heat pipe may not need a wick structure if gravity or some other source of acceleration is sufficient to overcome the surface tension and cause the condensed liquid to flow back to the heated end.

As illustrated in FIG. 3, the heat pipes 136 according to the present invention may be vertically aligned in some embodiments. In this device, and in the absence of a wick structure, geothermal energy from the earth 134 can be used to heat the airflow entering the compressor 52 (ie, the warmer earth-side end of the heat pipe 136 vaporizes a working fluid that is at the cold end of the heat pipe in the Inlet chamber 132 condenses, thereby warming the air flowing around it). This arrangement can be used when the earth temperature is greater than the air temperature, which may be effective during cold-day operation to prevent ice formation on equipment components.

According to an alternative embodiment of the present application object, a wick structure as described above can be used, so that the vertically oriented heat pipes of Fig. 3 can continue to be used when the earth temperature is lower than the ambient air temperature. In this case, plant operators may want to cool the ambient air supplied to the compressor. Instead of the force of gravity returning the condensed fluid to the cold side of the heat pipe, the capillary pressure created by the wick structure overcomes gravity, thereby wicking the condensed fluid upwardly from the colder earth side to the warmer side inside the chamber. When this is inside the chamber, the heat pipe absorbs heat from the passing airflow through the evaporation of the transported fluid. Cooling the air in this manner, as discussed, generally increases the efficiency of the gas turbine power plant and, when the ambient temperature is high, may be used to improve plant performance.

The advantages of using heat pipes for any required cooling or heating are manifold. First, heat pipes are entirely passive heat transfer systems that have no moving parts that could wear out. Second, heat pipes do not require energy for their operation. Third, heat pipes are relatively inexpensive. Fourth, heat pipes are flexible in size, shape, and effective operating temperature ranges.

In operation, when ambient temperatures fall below a desired level, heat pipes having the configuration illustrated in FIG. 3 may operate to pump heat from the subsurface to heat the air flowing through the inlet chamber 112. This can e.g. may be used to prevent unwanted ice from forming on the inlet side filter housing or inlet guide vanes. On the other hand, when the ambient temperatures rise above a desired level, heat pipes having the configuration illustrated in FIG. 3 may operate to pump heat from the air flowing through the inlet chamber 112 into the earth. This can e.g. be used on hot days to increase the efficiency of the system.

As illustrated in FIGS. 3 and 4, in some embodiments, the heat pipes may have multiple branches. The branches 138 generally increase the surface area for heat exchange with the earth.

Fig. 4 illustrates a front view of the inlet chamber 112 (i.e., looking into the mouth of the inlet chamber 112) and shows an exemplary configuration of the heat transfer structure 136 (in this case the heat pipes) within the inlet chamber according to one embodiment of the present application. As illustrated, the heat pipes may be vertically disposed and extend from the interior of the inlet chamber 112 to a desired depth within the ground 134. Several heat pipes may be evenly distributed across the inlet chamber 112. In certain applications, several or fewer heat pipes may be used.

Referring now to Fig. 5, there is illustrated an alternative embodiment of a gas turbine power plant according to the present application, a gas turbine power plant 150. In this case, a secondary heat transfer structure 152 is configured to exchange heat between the inlet chamber 112 and the exhaust of the turbine 54. In this type of power plant, as illustrated, a heat recovery steam generator 154 may be present. A portion of the turbine exhaust may be diverted from the main flow via an exhaust bypass 155 and passed through a heat transfer unit 156. Inside the heat transfer unit 156, the exhaust gas may heat the secondary heat transfer structure 152. The secondary heat transfer structure 152 may, as illustrated, be connected to the heat transfer structure 136, wherein the heat from the exhaust gas may be pumped into the inlet chamber 112. This configuration provides an additional heating element for the power plant which, as one skilled in the art will appreciate, may be required for certain applications. The secondary heat transfer structure 152 may have matching heat pipes with the description above.

As mentioned, the heat transfer structure 136 and the secondary heat transfer structure 152 in preferred embodiments have heat pipes. In other embodiments according to the present invention, the heat transfer structure 136 and the secondary heat transfer structure 152 may include other conventional heat transfer structures or systems. For example, For example, instead of the heat pipes, a heat sink or heat sink made of solid conductive metal pipes may be used. While the two-phase heat transfer associated with heat pipes can provide a more efficient heat transfer mode, single-phase heat transfer by heat conduction associated with certain solids may be sufficient for some applications. In other embodiments, a heat transfer fluid may be circulated through a circuit by a pump so that the fluid exchanges heat between the ground 134 and the inlet chamber 112. In still further embodiments, a thermosyphon may be employed. As one skilled in the art understands, a thermosyphon is a heat pipe-like device in which heat energy is transferred by fluid buoyancy rather than by evaporation and condensation.

Further, as will be understood by those skilled in the art, the many varying features and configurations described above with respect to the various exemplary embodiments may be optionally applied to form other possible embodiments of the subject application. For the sake of brevity, and taking into account the capabilities of one skilled in the art, all the possible iterations or steps are omitted or described in detail, although all combinations and possible embodiments encompassed by the several claims below or otherwise are a part of the present application subject form. Furthermore, those skilled in the art will recognize improvements, changes and modifications from the foregoing description of various exemplary embodiments of the invention. Such improvements, changes and modifications within the skill of the art are also intended to be covered by the appended claims. Furthermore, it should be apparent that the foregoing is directed to the described embodiments of the present application only and that numerous changes and modifications may be made thereto without departing from the scope and spirit of the invention as defined by the following claims and their equivalents. is deviated.

A geothermal heat exchange system for use in a gas turbine power plant that includes an inlet chamber 112 that directs airflow to a compressor 52 that compresses the airflow that is subsequently mixed with fuel in a combustor 56 and combusted such that the resulting hot gas flow is passed through a turbine 54, the ground heat exchanger system comprising: means for exchanging heat 136 between a ground 134 and the air flow passing through the inlet chamber 112.

Parts list:

[0042] <tb> 50 <sep> conventional gas turbine <Tb> 52 <sep> compressor <Tb> 54 <sep> turbine section <Tb> 56 <sep> combustion chamber <Tb> 60 <sep> compressor rotor blade <Tb> 100 <sep> Gas Turbine <tb> 112 <sep> inlet chamber, inlet plenum <Tb> 130 <sep> Gas Turbine Power Plant <tb> 134 <sep> Earth, ground or ground <Tb> 136 <sep> heat transfer structure <Tb> 138 <sep> branches <Tb> 150 <sep> Gas Turbine Power Plant <152> secondary heat transfer structure <Tb> 154 <sep> heat recovery steam generator <Tb> 155 <sep> exhaust bypass <Tb> 156 <sep> heat transfer unit

Claims (10)

A geothermal heat exchange system for use in a gas turbine power plant including an inlet chamber (112) that directs airflow to a compressor (52) that compresses the airflow, the compressed airflow subsequently being mixed with a fuel and burned in a combustor (56) so that the resulting hot gas flow is passed through a turbine (54), the geothermal heat exchanger system comprising: means for exchanging heat (136) between a ground (134) and the airflow passing through the inlet chamber (112). The earth heat exchanger system of claim 1, wherein the means for exchanging heat (136) between the earth (134) and the airflow passing through the inlet chamber (112) comprises a heat pipe. 3. The geothermal heat exchanger system of claim 1, wherein the means for exchanging heat (136) between the earth (134) and the airflow passing through the inlet chamber (112) comprises either a heat sink or a thermosyphon. 4. The geothermal heat exchanger system of claim 1, wherein the means for exchanging heat (136) between the earth (134) and the air flow passing through the inlet chamber (112) comprises a heat transfer fluid circulated by a pump through a circuit passing through the earth (134) and the inlet chamber (112) extend; and wherein the earth (134) has either a location below the surface of the earth or a location below the surface of a body of water. 5. The geothermal heat exchanger system of claim 1, wherein the earth (134) has a location at a predetermined depth below the surface of the earth; and wherein the predetermined depth has a depth greater than 25 feet. 6. The geothermal heat exchanger system according to claim 2, wherein the heat pipe includes a two-phase heat transfer device including a sealed pipe made of a high thermal conductivity material; and wherein the sealed tube is depleted of air and filled with a small amount of a working fluid. 7. The geothermal heat exchanger system of claim 6, wherein the heat pipe is substantially vertically aligned and has a wick structure, wherein the wick structure comprises a material configured to achieve a desired capillary pressure on the condensed working fluid. 8. The geothermal heat exchanger system of claim 6, wherein the wick structure has a structure of a groove wick structure, a wire mesh wick structure, a powder metal wick structure, and a fiber / spring wick structure; and wherein the heat pipe is configured to transfer heat from the airflow passing through the inlet chamber (112) to the earth (134) on hot days, thereby increasing the efficiency of the gas turbine power plant. 9. The geothermal heat exchanger system of claim 6, wherein the heat pipe is configured to transfer heat from the earth (134) to the airflow passing through the inlet chamber (112) on cold days such that undesirable ice formation is avoided. The geothermal heat exchanger system of claim 6, further comprising means for transferring heat (152) between exhaust flow from the turbine and the inlet chamber (112); wherein the means for transferring heat (152) between the exhaust gas flow from the turbine and the inlet chamber (112) comprises a heat pipe.