JP6431725B2 - System and method for deicing a gas turbine engine intake screen and dehumidifying an intake air filter - Google Patents

Description

  The subject matter disclosed herein relates generally to gas turbine engines, and more particularly to methods and systems for preventing icing of an intake screen of a gas turbine engine.

  Gas turbine engines typically ignite a fuel / air mixture to compress the incoming air and to mix the fuel and compressed air and to form a hot gas stream. And a turbine section driven by a hot gas stream.

  Gas turbine engines are used globally for power generation or as mechanical drives for operating pumps and compressors under various climatic conditions. Operation at cold ambient temperatures and high humidity conditions often causes ice to accumulate on the turbine intake filter house components. Often, this ice build-up on air filter elements (bird screens, moisture separators, coalescer filters and filter modules) is severe enough to limit air flow and increase the filter house intake pressure drop. As a result, it results in a loss of combustion turbine performance or even a shutdown. When water taken as a liquid or solid near or below freezing (wet snow, freezing rain, etc.) adheres to most exposed surfaces, icing occurs and ice is deposited. Also, ice forms when saturated cooling air contacts the cooler filter house surface.

  One common method for treating inlet ice build-up is to remove the water separator and coalescer filter attached to the inlet rain shield and install a heating coil supplied with hot air or steam or a hot water / glycol mixture. Use to heat the ambient air upstream of the air filter module.

  According to typical prior art anti-icing systems, exhaust gas is recirculated by placing a bypass valve in the stack channel. This allows sufficient exhaust gas to be constantly recirculated to the inlet to maintain a minimum + 40 ° F. turbine inlet temperature. This method has the disadvantage of increasing turbine exhaust pressure, thereby negatively impacting the performance of the gas turbine engine.

  Another type of anti-icing device provides heating during ambient conditions that promote ice formation in air filters, internal filter house walls, and downstream gas turbine components such as inlet guide vanes and compressor first stage blades, for example In order to do this, a heating coil arranged before the intake filter is used. In coil-based systems, heat is supplied to the coil in the form of a hot water / glycol mixture or low pressure (LP) steam. This approach can increase capital costs and negatively impact production efficiency by year of operation due to, for example, additional airflow restrictions (pressure drops) imposed by heating coils.

  Another method is to provide a plurality of heating panels (bundles) located at or adjacent to the intake air filter house of the turbine. Each heating panel is provided with one or more electrical resistance heating elements. A controller for selectively operating each resistive heating element of the plurality of heating panels is also provided.

US Patent Application Publication No. 2013/0193127

  The present disclosure provides a solution to the problem of preventing gas turbine engine intake screen ice buildup without significantly degrading performance.

  According to one exemplary, non-limiting embodiment, the present invention relates to a method for heating an intake screen of a gas turbine. The method includes determining a current intake screen temperature and determining a desired intake screen temperature. If the current intake screen temperature is lower than the desired intake screen temperature, the method includes calculating a first flow rate of the air-exhaust mixture necessary to achieve the desired intake screen temperature. The method also includes extracting an exhaust gas amount from the turbine exhaust subsystem, extracting an air amount from the compressor stage, and generating an air-exhaust mixture without increasing the pressure of the turbine exhaust subsystem. In order to do so, a step of mixing the exhaust gas amount and the air amount is included. The method also includes the step of conveying the air-exhaust mixture to the intake screen, wherein the air-exhaust mixture is conveyed at a flow rate equivalent to the first flow rate.

  In another embodiment, the system includes a compressor, a turbine having an exhaust system, and an intake screen. The manifold is connected to the intake screen. The mixing component has a first input, a second input and an output. The first conduit is coupled to the first input of the compressor stage and the mixing component. The second conduit is connected to a second input of the exhaust system and the mixing component, and the second conduit is suitable for extracting exhaust gas without increasing the exhaust system pressure. The third conduit is connected to the output of the mixing part and to the manifold.

  In another embodiment, a system is provided that includes a compressor, a combustion system, a turbine, and a turbine exhaust subsystem. The system includes a compressor inlet coupled to the compressor and an intake screen coupled to the compressor inlet. The manifold is connected to the intake screen. A compressor extraction subsystem suitable for extracting air from the compressor is coupled to the compressor stage. The exhaust extraction subsystem is suitable for extracting exhaust gas without increasing the pressure of the exhaust subsystem and is coupled to the turbine exhaust subsystem. The mixing component is coupled to a compressor extraction subsystem and an exhaust extraction subsystem. The mixing component is suitable for mixing air and exhaust gas to produce an air-exhaust mixture. The first conduit is connected to the mixing component and the manifold and carries the air-exhaust mixture to the manifold.

  Other features and advantages of the present invention will become apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, for example, the principles of certain aspects of the invention.

1 is a schematic diagram of an embodiment of a system for deicing a gas turbine engine intake screen. FIG. 1 is a schematic diagram of an embodiment of a control system used in a system for deicing a gas turbine engine intake screen. FIG. 3 is an alternative embodiment of a system for deicing a gas turbine engine intake screen. 3 is an alternative embodiment of a system for deicing a gas turbine engine intake screen. 3 is a flowchart illustrating a method for deicing a gas turbine intake screen. 6 is a flow chart showing additional steps of a method for deicing a gas turbine intake screen.

  FIG. 1 illustrates an embodiment of a gas turbine system 100 having the ability to deicing an intake screen. The gas turbine system 100 may include one or more gas turbine engines 101. Each gas turbine engine 101 includes a compressor 105 that compresses the incoming air stream. The compressor 105 supplies a compressed air flow to the combustion subsystem 110 where the compressed air flow mixes with the compressed fuel flow and the mixture is ignited to produce a combustion gas flow. . The flow of combustion gas is fed one after another to the turbine 115 and drives the turbine 115 to generate mechanical work. The mechanical work generated by the turbine 115 drives the compressor 105 and an external load such as a generator. The flow of combustion gas may be exhausted to the exhaust stack via the exhaust subsystem 120 or may be discarded.

  The gas turbine engine 101 may include a compressor intake subsystem 125 having an articulated inlet guide vane assembly 130 that extends substantially circumferentially within the gas turbine engine 101.

  The gas turbine engine 101 may include an intake screen 135 or filter house, and the filter assembly removes moisture and particulate matter such as dust and / or debris from the air flowing to the gas turbine engine 101. 136.

  The gas turbine system 100 may also include a compressor bypass conduit 140 (first conduit) used to extract the amount of compressed air from the compressor 105 stage. Associated with the compressor bypass conduit 140 is a first conduit control subsystem 145 that may include a first conduit control valve 150 and a first conduit flow sensor 155. The gas turbine system 100 also includes an exhaust bypass conduit 160 (second conduit) and a second conduit control subsystem 165. The exhaust bypass conduit 160 extracts the amount of exhaust gas from the exhaust subsystem 120 without increasing the pressure of the exhaust subsystem 120 (eg, by suction). The second conduit control subsystem 165 may include a second conduit cutoff valve 170. The exhaust gas flowing through the exhaust bypass conduit 160 may be mixed with filtered air from the filtered air source 175. The amount of filtered air is controlled by a filtered air control valve 180. An alternative non-filtered air source 176 may be unfiltered and controlled by control valve 181 and mixed with the exhaust bypass conduit 160 flow.

  The air from the compressor bypass conduit 140 and the exhaust gas from the exhaust bypass conduit 160 may or may not be mixed with filtered or non-filtered air, but at a mixing component 185 such as an eductor, for example. Mixed. As known to those skilled in the art, an eductor is a type of jet pump that does not require any moving parts capable of pumping liquid or gas from a particular area. These pumps use their structure to transfer energy from one fluid to another by the venturi effect. In the eductor, the drive fluid (the pressurized air from the compressor 105) passes through the eductor nozzle and converts the pressure energy into a jet. The result of this is that the fluid at the head of the jet is displaced, creating a low pressure region at the outlet of the nozzle. As a result, a flow to be sucked is generated, and exhaust gas is sucked in via the branch inlet of the eductor. The compressed air and the inhaled exhaust gas are mixed as they travel through the eductor diffuser. The velocity energy of the air-exhaust gas mixture is changed to pressure energy so that the air-exhaust gas mixture is discharged from the eductor with a back pressure stronger than the blowing pressure.

  The mixture of air and exhaust gas is conveyed to the third conduit 190. A portion of the air and exhaust gas mixture may be conveyed to the intake bleed heat manifold (IBH manifold 200) by an intake bleed heat conduit (IBH conduit 195). The amount of air / exhaust gas mixture conveyed to the IBH manifold 200 is controlled by the IBH bypass control valve 205. Also, a portion of the air-exhaust gas mixture may be conveyed to the anti-icing manifold 215 through the intake screen conduit 210. The amount of air-exhaust gas mixture conveyed to the anti-icing manifold 215 is controlled by the intake screen control valve 220. The mixture of air and exhaust gas is further mixed with ambient air from the ambient air intake 225. If the entire flow of the third conduit 190 is conveyed to the anti-icing manifold 215, an alternative non-filtered air source 176 can be utilized to minimize the duty of the intake air filter 136.

  In operation, compressed air (temperature Tcsn) from compressor 105 stage is conveyed to mixing component 185. Exhaust gas (temperature Tex) is extracted from the exhaust subsystem 120 without increasing the pressure of the exhaust subsystem 120 as a result of the low pressure region generated by the mixing component 185 (eg, eductor). The amount of compressed air and exhaust gas conveyed to the mixing component 185 is the desired temperature of the intake screen 135 (desired Tis), the actual temperature of the intake screen 135 (actual Tis), the desired temperature of the intake air filter 136. (Desired Tfilter), the desired compressor inlet temperature (desired Tinlet), the actual compressor inlet subsystem 125 temperature (actual Tinlet), and the ambient temperature (Tamb). The relative amount of air or gas is calculated using a mass flow calculation and is controlled by the first conduit control valve 150, the second conduit cutoff valve 170, the IBH bypass control valve 205 and the intake screen control valve 220. .

  As shown in FIG. 2, the positions of the first conduit control valve 150, the second conduit cutoff valve 170, the IBH bypass control valve 205, the filtered air control valve 180, the control valve 181 and the intake screen control valve 220 are: It is controlled by the controller 235. In particular, the controller 235 can also receive input from the flow sensor 155 of the first conduit. The controller 235 may be an independent controller or may be integrated with a gas turbine control system.

  An example of a gas turbine control system is General Electric's Speedtronic® Mark VI® control system, which is designed to meet all gas turbine control requirements. It functions to control fuel flow at part load conditions, functions to control speed and load, and temperature control to limit the fuel flow to a maximum value consistent with achieving the rated combustion temperature, and Including controlling the airflow through the inlet guide vanes. The Mark VI® control system handles auxiliary device sequencing to allow fully automated start, stop, and cool down. The base system incorporates gas turbine system protection against adverse operating conditions and warning of abnormal conditions. Thus, the control system provides fuel, air and emissions control, fuel and auxiliary device ordering for start, stop and cool down, generator and system synchronization and voltage matching, all turbines, control and auxiliary functions Perform many functions, including monitoring and protection against unsafe and adverse operating conditions. All of these functions are performed in an integrated manner to perform the desired pre-programmed and / or operator input control philosophy.

  In another embodiment shown in FIG. 3, the compressor bypass conduit 140 may be coupled to the compressor outlet 221. The compressed air from the compressor discharge port 221 is mixed with the exhaust gas extracted from the exhaust subsystem 120 by suction. This can be accomplished using a mixing component 185 such as an eductor, for example.

In another embodiment shown in FIG. 4, the second conduit (exhaust bypass conduit 160) may be a large diameter duct having a cutoff valve 226 and a control valve 230. The exhaust gas in a combined cycle configuration is typically at a pressure of about 12 inches H ₂ O. This positive pressure relative to the ambient pressure is the driving force that transports a portion of the exhaust flow to the anti-icing manifold 215. Given the relatively low supply pressure of the exhaust gas, this bypass duct can be, for example, about the cross-sectional area of the exhaust bypass conduit 160 leading from the gas turbine exhaust to the heat recovery steam generator inlet to accommodate the required bypass flow rate. It is anticipated that it may have a cross-sectional area of 30%.

  FIG. 5 illustrates a method 300 for deicing the intake screen 135 of the gas turbine engine 101.

  In step 305, the method 300 determines the current temperature of the intake screen 135.

  In step 310, the method 300 determines a desired temperature of the intake screen 135. The desired temperature of the intake screen 135 may be a temperature sufficient to deice the intake screen 135 or dehumidify the intake air filter 136 to prevent the formation of ice or water droplets.

  In step 315, the method 300 determines whether the current temperature of the intake screen 135 is lower than the desired temperature of the intake screen 135. If the current temperature of the intake screen 135 is lower than the desired temperature of the intake screen 135, the following additional steps are included in the method.

  In step 316, the method 300 determines the exhaust temperature.

  In step 317, the method 300 determines the compressor stage temperature.

  In step 320, the method 300 calculates a first flow rate of the exhaust-air mixture necessary to achieve the desired temperature of the intake screen 135.

  In step 325, the method 300 extracts the amount of exhaust gas from the turbine exhaust system by suction.

  In step 330, the method 300 mixes the amount of exhaust gas and the amount of air to produce an air-exhaust mixture. Also, the air-exhaust gas mixture may be mixed with filtered air.

  In step 335, the method 300 extracts the amount of air from the compressor stage.

  At step 340, the method 300 mixes the exhaust or air-exhaust mixture with the air from the compressor stage. Step 340 can be accomplished by an eductor.

  In step 345, the method 300 delivers the air-exhaust mixture to the intake screen at a flow rate equivalent to the first flow rate. This can be achieved by adjusting the intake screen control valve 220.

  FIG. 6 shows an additional step 350 that may be performed by the method 300.

  In step 355, the method 300 determines the current temperature of the compressor intake subsystem 125.

  At step 360, the method 300 determines a desired temperature for the compressor intake subsystem 125.

  At step 365, the method 300 determines whether the current temperature of the compressor intake subsystem 125 is lower than the desired temperature of the compressor intake subsystem 125. If the current temperature of the compressor intake subsystem 125 is lower than the desired temperature of the compressor intake subsystem 125, the method 300 performs the following additional steps.

  In step 370, the method 300 calculates a second flow rate of the air-exhaust mixture that is required to achieve the desired temperature of the compressor intake subsystem 125.

  In step 375, the method 300 extracts the amount of exhaust gas from the turbine exhaust system without increasing the pressure of the turbine exhaust system.

  In step 380, the method 300 extracts the amount of air from the compressor stage.

  In step 385, the method 300 mixes the exhaust and air amounts to produce an air-exhaust mixture.

  In step 390, the method 300 delivers the air-exhaust mixture to the compressor inlet at a flow rate equivalent to the second flow rate.

  The method 300 avoids intake screen icing and optimizes the performance of the gas turbine system 100 by controlling the temperatures of the anti-icing manifold 215 and the IBH manifold 200. This is achieved without increasing the exhaust system pressure, thereby avoiding negative performance effects.

  Where the definition of a term departs from the commonly used meaning of the term, Applicant intends to use the definition provided below unless otherwise indicated.

  The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Where the definition of a term departs from the commonly used meaning of the term, Applicant intends to use the definition provided below unless otherwise indicated. Unless the context clearly dictates otherwise, the singular is intended to include the plural. It will be appreciated that the terms first, second, etc. may be used to describe various elements, but these elements should not be limited by these terms. These terms are only used to distinguish one element from another. The term “and / or” includes any and all combinations of one or more of the listed items concerned. The phrases “coupled to” and “coupled to” allow for direct or indirect coupling.

  This specification is intended to disclose the invention, including the best mode, and to embody the invention including any person skilled in the art making and using any device or system and performing any incorporated methods. The example is used so that it can be done. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. If such other embodiments have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements, such other embodiments are within the scope of the claims. Intended to be.

100 Gas turbine system 101 Gas turbine engine 105 Compressor 110 Combustion subsystem 115 Turbine 120 Exhaust subsystem 125 Compressor intake subsystem 130 Articulated inlet guide vane assembly 135 Intake screen 136 Intake air filter 140 Compressor bypass conduit 145 First conduit Control subsystem 150 First conduit control valve 155 First conduit flow sensor 160 Exhaust bypass conduit 165 Second conduit control subsystem 170 Second conduit cutoff valve 175 Filter air source 176 Alternative non-filter Air source 180 Filtered air control valve 181 Control valve 185 Mixing part 190 Third conduit 195 IBH conduit 200 IBH manifold 205 IBH bypass control valve 210 Intake screen conduit 215 Anti-icing manifold Yield 220 Inlet Screen Control Valve 221 Compressor Outlet 225 Ambient Air Intake 226 Shutoff Valve 230 Control Valve 235 Controller 300 Method 305 for Deicing the Intake Screen Step 305 Determining the Current Temperature of the Intake Screen 310 Desired Intake Screen Step 315 determining the temperature of the intake screen 135 determining whether the current temperature of the intake screen 135 is lower than the desired temperature of the intake screen step 316 determining the exhaust temperature step 317 determining the temperature of the compressor stage 320 determining the desired intake screen Calculating a first flow rate of the exhaust-air mixture required to achieve the temperature of step 325 extracting an amount of exhaust gas from the turbine exhaust system by suction; 330 generating an air-exhaust mixture to produce an air-exhaust mixture Gas volume and air volume Step 335 Mixing Step 340 Extracting the amount of air from the compressor stage Step 340 Mixing the exhaust or air-exhaust gas mixture and the air from the compressor stage Step 345 The air-exhaust gas mixture on the intake screen at a flow rate equivalent to the first flow rate Additional step 355 determining the current temperature of the compressor intake subsystem 360 determining the desired temperature of the compressor intake subsystem 365 the current temperature of the compressor intake subsystem 125 is the compressor intake subsystem Step 370 to determine whether the temperature is below the desired temperature of 125 Step 375 to calculate the second flow of the air-exhaust mixture required to achieve the desired temperature of the compressor intake subsystem 375 Rise Step 380 for extracting the amount of exhaust gas from the turbine exhaust system without step Step 385 for extracting the amount of air from the compressor stage Step 390 for mixing the amount of exhaust gas and the amount of air in order to generate an air-exhaust mixture Step of conveying the air-exhaust gas mixture to the compressor inlet at a flow rate equivalent to the flow rate of 2

Claims (7)

A compressor (105);
A turbine (115) having an exhaust device;
An intake screen (135);
An anti-icing manifold coupled to the intake screen (135);
An eductor functioning as a mixing component (185) having a first input, a second input and an output;
A first conduit (140) coupled to the first input of the compressor stage (105) and the eductor (185);
A second conduit (160) coupled to the second input of the exhaust system and the eductor (185) and suitable for extracting exhaust gas by suction;
A third conduit (190) coupled to the output of the eductor (185) and the anti-icing manifold;
A first control valve (181) disposed in the first conduit (140);
A first cutoff valve (226) disposed in the second conduit (160);
A second control valve (230) disposed in the third conduit (190);
Including
A single controller controls the first control valve (181) and the first cutoff valve (226) depending on the current temperature of the intake screen (135) and the desired temperature of the intake screen (135). And a signal for controlling the position of the second control valve (230),
System (100).   The system (100) of claim 1, further comprising an IBH system coupled to the compressor (105), and an IBH manifold (200) coupled to the third conduit (190) and the IBH system. . The anti-icing manifold is connected upstream of the intake screen (135);
An air and exhaust gas mixture from the output of the eductor (185) is mixed with ambient air from an ambient air intake (225);
A combustor coupled to the compressor (105) and the turbine (115);
The system (100) of claim 1 or 2, further comprising a heat recovery steam generator coupled to the turbine (115). A compressor (105);
A combustion system (110);
A turbine (115);
A turbine exhaust subsystem (120);
A compressor inlet connected to the compressor (105);
An intake screen (135) coupled to the compressor intake;
An anti-icing manifold coupled to the intake screen (135);
A compressor extraction subsystem coupled to the compressor stage (105) and suitable for extracting air from the compressor (105);
An exhaust extraction subsystem comprising a second conduit (160) coupled to the turbine exhaust subsystem (120) and suitable for extracting exhaust gas using suction;
Connected to the compressor extraction subsystem and the exhaust extraction subsystem and functions as a mixing component (185) comprising a third conduit (190) for mixing the air and exhaust gas to produce an air-exhaust mixture Eductor to do,
A first conduit (140) coupled to the eductor (185) and the anti-icing manifold and carrying the air-exhaust mixture to the anti-icing manifold;
A first control valve (181) disposed in the first conduit (140);
A first cutoff valve (226) disposed in the second conduit (160);
A second control valve (230) disposed in the third conduit (190);
Including
A single controller controls the first control valve (181) and the first cutoff valve (226) depending on the current temperature of the intake screen (135) and the desired temperature of the intake screen (135). And a signal for controlling the position of the second control valve (230),
System (100). An intake bleed thermal manifold coupled to the compressor inlet;
The system (100) of claim 4, further comprising a second conduit (160) coupled to the eductor (185) and the intake bleed thermal manifold. A first control subsystem (145) disposed in the first conduit (140);
A second control subsystem (165) coupled to the exhaust extraction subsystem;
The system (100) of claim 4 or 5, further comprising a third control subsystem coupled to the compressor extraction subsystem. The anti-icing manifold is connected upstream of the intake screen (135);
An air and exhaust gas mixture from the output of the eductor (185) is mixed with ambient air from an ambient air intake (225);
A mechanical load coupled to the turbine (115);
The system (100) according to any of claims 4 to 6, further comprising a steam turbine coupled to the turbine exhaust subsystem (120).