System and method for efficient detection of harmful fuel gas leaks in a gas turbine compartment

Abstract

To provide improved hazardous gas detection systems and methods.SOLUTION: The present application provides a hazardous gas detection system (100) to determine hazardous gas concentrations and / or temperatures within a flow of exhaust air (98) in an exhaust duct (80) of a gas turbine compartment (65). The hazardous gas detection system (100) may include one or more sensors (115) positioned within the exhaust duct (80) or in communication with the exhaust duct (80), and a static mixer (210) positioned upstream of the one or more sensors (115) to promote mixing of the flow of exhaust air (98).SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] This application and the resulting patent generally relate to gas turbine engines, and more particularly, to an improved system and method for the efficient detection of fuel gas leakage within a gas turbine compartment by the use of a static mixer to promote uniform gas concentration and temperature in a harmful gas sensor.

Background Art

[0002] Gas turbine engines and their associated components and systems are often at least partially disposed within a compartment or other type of enclosure. Generally speaking, a gas turbine compartment protects the gas turbine engine from local environmental conditions, reduces acoustic emissions from the gas turbine engine, and insulates the immediate surroundings from the heat generated by the gas turbine engine during operation.

[0003] A harmful gas detection system can be deployed within and / or proximate to a gas turbine compartment. The harmful gas detection system can use a gas sensor to detect or measure the concentration of harmful gases in the exhaust air exiting the compartment via a ventilation exhaust duct. However, the concentration of harmful gases can be highly stratified within the ventilation exhaust duct. In other words, the concentration of harmful gases may not be uniform in the plane where the harmful gas sensor is located due to the amount, location, and direction of leakage within the compartment. Therefore, leaked fuel gas within the compartment may not be detected by the harmful gas sensor, or may be detected at a lower lower explosive limit concentration ("LEL") than the actual concentration, or vice versa. Similar problems exist with respect to air temperature since sensor readings can depend on the location of thermocouples within the ventilation exhaust duct.

[0004] For example, if the concentration of a hazardous gas reaches its lower explosive limit or a predetermined percentage of the lower explosive limit for a particular hazardous gas, the gas turbine engine must be shut down or tripped to address the leak. False or abnormal readings can result in unnecessary shutdowns of the gas turbine engine, at the expense of gas turbine life, power availability, and / or revenue loss resulting from taking the power plant offline. Therefore, improved hazardous gas detection systems and methods are desired. Such systems and methods can improve the overall reliability and availability of gas turbine engines by preventing false alarms and / or controlled shutdowns or trips of the gas turbine engine. [Overview of the Initiative]

[0005] Accordingly, this application and the resulting patents provide a hazardous gas detection system for determining the concentration and temperature of hazardous gases in the exhaust airflow within an exhaust duct of a gas turbine compartment. The hazardous gas detection system may include one or more sensors positioned within or in communication with the exhaust duct, and one or more static mixers positioned upstream of the sensors to facilitate mixing of the exhaust airflow.

[0006] This application and the resulting patent further provide a method for determining the concentration or temperature of harmful gases in an exhaust airflow within an exhaust duct of a gas turbine compartment. The method may include the steps of drawing an exhaust airflow into an exhaust duct, positioning a static mixer in the exhaust airflow, uniformly mixing harmful gases in the exhaust airflow, and detecting the concentration or temperature of the harmful gases.

[0007] This application and the resulting patent further provide a hazardous gas detection system for determining the concentration and temperature of hazardous gases in the exhaust airflow within an exhaust duct of a gas turbine compartment. The hazardous gas detection system may include one or more gas sensors and one or more temperature sensors positioned within or in communication with the exhaust duct, and a static mixer positioned upstream of the one or more gas sensors and one or more temperature sensors to facilitate mixing of the exhaust airflow.

[0008] These and other features and improvements of this application and the resulting patent will become apparent to those skilled in the art by examining the following detailed description in conjunction with some drawings and the attached claims. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of an exemplary gas turbine engine positioned within a gas turbine compartment equipped with a ventilation exhaust duct having a hazardous gas detection system. [Figure 2A] This is a schematic diagram of a hazardous gas detection system that can be used in conjunction with the gas turbine compartment shown in Figure 1. [Figure 2B] This is a schematic diagram of an alternative embodiment of a hazardous gas detection system that can be used in conjunction with the gas turbine compartment shown in Figure 1. [Figure 3] Figure 1 is a schematic diagram of a gas turbine compartment and ventilation exhaust duct with a hazardous gas detection system, illustrating an exemplary static mixer. [Figure 4] Figure 1 shows a schematic diagram of a gas turbine compartment and ventilation exhaust duct with a hazardous gas detection system, illustrating a further example of a static mixer. [Figure 5] Figure 1 shows a schematic diagram of a gas turbine compartment and ventilation exhaust duct with a hazardous gas detection system, illustrating a further example of a static mixer. [Figure 6] This is a perspective view of a static mixer that can be used with a hazardous gas detection system. [Figure 7]A perspective view of a further example of a static mixer that can be used in conjunction with a hazardous gas detection system. [Figure 8] A perspective view of a further example of a static mixer that can be used in conjunction with a hazardous gas detection system. [Figure 9] A perspective view of a further example of a static mixer that can be used in conjunction with a hazardous gas detection system. [Figure 10] A perspective view of a further example of a static mixer that can be used in conjunction with a hazardous gas detection system. [Modes for carrying out the invention]

[0010] Referring here to the drawings, the same reference numerals throughout several figures refer to the same elements, and Figure 1 shows a schematic diagram of a gas turbine engine 10 as may be used herein. The gas turbine engine 10 may include a compressor 15. The compressor 15 compresses a flow of air 20 that flows in through an inlet section 25. The compressor 15 delivers the compressed air 20 flow to several combustor cans 30. The combustor cans 30 mix the compressed air 20 flow with a flow of pressurized fuel 32 and ignite the mixture to produce a flow of hot combustion gases 40. Although only a single combustor can 30 is shown, the gas turbine engine 10 may include any number of combustor cans 30 positioned in a circumferential array, etc. The flow of hot combustion gases 40 is then delivered to a turbine 45. The flow of hot combustion gases 40 drives the turbine 45 to generate mechanical work. The mechanical work generated in the turbine 45 drives the compressor 15 via a shaft 50 and a generator 55 or other type of external load, etc. The high-temperature combustion gas 40 can exit the gas turbine engine 10 via the exhaust section 60 and the like.

[0011] The gas turbine engine 10 may use natural gas, various types of synthesis gas, liquid fuels, and / or other types of fuels, as well as blends thereof. The gas turbine engine 10 may be any one of the many different gas turbine engines offered by General Electric Company in Schenectady, New York, including, but not limited to, engines such as the 7 or 9 Series Heavy Duty Gas Turbine Engines. The gas turbine engine 10 may have different configurations and may use other types of components. Other types of gas turbine engines may also be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment may also be used together herein.

[0012] The gas turbine engine 10 may be at least partially enclosed within a gas turbine compartment 65. The gas turbine compartment 65 may have any suitable size, shape, or configuration. The gas turbine compartment 65 may include a ventilation system 70. The ventilation system 70 may include at least one ventilation inlet duct 75, at least one ventilation exhaust duct 80, and one or more fans or blowers 85 for drawing ventilation air 90 through the gas turbine compartment 65 and through the ventilation exhaust duct 80 into the ventilation inlet duct 75. The ventilation air 90 can provide cooling to the gas turbine engine 10. If fuel gas 95 or other types of harmful gases leak from one or more fuel flanges or other types of fuel connections, the fuel gas 95 or other types of harmful gases may mix with the ventilation air 90 through the ventilation exhaust duct 80 of the ventilation system 70 and flow out of the gas turbine compartment 65 as exhaust air 98. Other components and configurations may be used herein.

[0013] Figure 2A shows a hazardous gas detection system 100 that may be described herein. In this example, the hazardous gas detection system 100 may be located within the instrumentation duct 110 (shown in Figure 1) of the ventilation exhaust duct 80 or elsewhere. The hazardous gas detection system 100 is in the path of exhaust air 98 flowing from the gas turbine compartment 65 via the ventilation exhaust duct 80.

[0014] The hazardous gas detection system 100 may include one or more sensors 115 located on or in communication with one or more sampling tubes 120. In this example, a first air sampling tube 130, a second air sampling tube 140, and a temperature sampling tube 150 are shown. Any number or type of sampling tubes 120 may be used herein. Each of the sampling tubes 120 may have a substantial "U" shape, etc. The first air sampling tube 130 may have several first air sampling ports 160 positioned thereon. The second air sampling tube 140 may have several second air sampling ports 170. Four first air sampling ports 160 and four second air sampling ports 170 are shown, but any number may be used. The temperature sampling tube 150 may have several thermocouples 180 or other types of temperature sensors positioned thereon. Four thermocouples 180 are shown, but any number may be used. Other components and configurations may be used in this specification.

[0015] A sampling tube 120 may extend from an instrumentation duct 110. A first air sampling tube 130 may communicate with a first gas sensor 190. A second air sampling tube 140 may communicate with a second gas sensor 200. The gas sensors 190 and 200 may be infrared gas sensors or the like. The gas sensors 190 and 200 may be configured to detect the concentration of specific harmful gases in the flow of exhaust air 98. Specifically, the exhaust air 98 may flow into the instrumentation duct 110, into the air sampling tubes 130 and 140, and pass through the gas sensors 190 and 200. The gas sensors 190 and 200 can communicate with a controller (not shown) and / or a dedicated controller of the gas turbine engine 10. The gas sensors 190 and 200 can transmit signals to the controller corresponding to the gas concentration in the exhaust air 98.

[0016] Similarly, the temperature tube 150 can extend from the instrumentation duct 110. Exhaust air 98 flows into the instrumentation duct 110 and can pass through the thermocouple 180 or other types of temperature sensors. The thermocouple 180 can communicate with the controller of the gas turbine engine 10 and / or a dedicated controller. The thermocouple 180 can transmit a signal to the controller corresponding to the temperature of the exhaust air 98.

[0017] Figure 2B shows a similar configuration of the instrumentation duct 110. In contrast to the grouped configuration of the sampling tubes 120 described above, the sensor 115 itself may be in the flow of exhaust air 98. The sensor 115 can individually detect the concentration or temperature of the flow of exhaust air 98. The sensor 115 can communicate with a controller or the like. Any number of sensors 115 may be used in this specification.

[0018] As described above, the controller can stop the gas turbine engine 10 based on the gas concentration and / or temperature in the flow of the exhaust air 98 outside the predetermined range detected by the harmful gas detection system 100. However, the concentration and / or temperature of the flow of the exhaust air 98 may be stratified. For example, different readings may be generated based on the location of the leak, the direction of the leak, the magnitude of the leak, and the proximity of the leak to the sensors 190, 200 of the harmful gas detection system 100 within the gas turbine compartment 65.

[0019] Therefore, the harmful gas detection system 100 can include a static mixer 210 as shown in FIGS. 3 to 5. The static mixer 210 is positioned within the flow path of the exhaust air 98 and can generate a more uniform or homogeneous mixture of the leaked fuel gas 95 and the ventilation air 90 upstream of the instrumentation duct 110. With a more uniform or homogeneous mixture of the exhaust air 98, the harmful gas detection system 100 can detect the leaked fuel gas 95 more easily and with higher reliability. The static mixer 210 may be of any type of two-dimensional or three-dimensional structure that promotes good mixing of the gas with a minimum pressure drop overall.

[0020] The static mixer 210 can have several different configurations and locations. For example, the static mixer 210 can be positioned within the gas turbine compartment 65 adjacent to the ventilation exhaust duct 80 as shown in FIG. 3. Alternatively, the static mixer 210 may be positioned within the ventilation exhaust duct 80 adjacent to the gas turbine compartment 65 as shown in FIG. 4. Similarly, the static mixer 210 can be positioned within the ventilation exhaust duct 80 adjacent to the instrumentation duct 110 as shown in FIG. 5. Other locations and other configurations may be used herein.

[0021] Regardless of location, the static mixer 210 has an overall pressure drop to achieve good mixing. Considering that the pressure drop is largely proportional to the square of the velocity of the exhaust air 98 passing through, the location of the static mixer 210 within the gas turbine section 65 as shown in FIG. 3 can have the lowest velocity and thus the lowest pressure drop. As shown in FIG. 4, the velocity of the exhaust air 98 can increase as the flow enters the smaller ventilation exhaust duct 80, and as shown in FIG. 5, it can further increase as the flow extends into the instrumentation duct 110. Therefore, the pressure drop increases near the inlet of the ventilation exhaust duct 80 and further increases near the instrumentation duct 110. The higher the pressure drop, the more necessary it may be to increase the size of the fan 85 from the perspective of the static head rise capacity. When a higher static head capacity is required, a more expensive fan 85 (in terms of size and operating costs) may be needed.

[0022] FIGS. 6 - 10 show different examples of the static mixer 210. In FIG. 6, the static mixer 210 can include an outer shell 220 and a pair of ducts 230. Each duct 230 can have a generally rectangular shape 240 with a side inlet wall 250, a side outlet wall 260, a pair of top walls 270, a pair of bottom walls 280, and a pair of lateral side walls 290. (The listed positions of top, bottom, and side are only with respect to their respective orientations. The walls can be considered top, bottom, or side depending on the orientation.) The side inlet wall 250 and the side outlet wall 260 of each duct 230 can have several openings 300 inside. The size and position of the openings 300 can vary. The ducts 230 may be positioned in an intersecting offset configuration 310. Specifically, both the side inlet wall 250 and the side outlet wall 260 may be offset from each other by about 90 degrees. Other angles may be used herein. The static mixer 210 can be made from any type of material suitable for the high - temperature environment of the gas turbine section 65 and the flow of the exhaust air 98. Other components and other configurations may be used herein.

[0023] During use, the exhaust air 98 enters the side inlet walls 250 of each duct 230 at an angle, where it undergoes turbulent mixing before exiting through the side outlet walls 260. The use of the openings 300 further promotes turbulence and mixing within them. The exhaust air 98 continues to mix downstream of the static mixer 210 until a substantially homogeneous or more homogeneous flow reaches the instrumentation duct 110 and sampling tube 120.

[0024] Figure 7 shows a similar example of a static mixer 210 with additional openings 300 positioned within adjacent lateral side walls 290. These lateral openings further facilitate lateral mixing between ducts 230. Figure 8 shows a further example of a static mixer 210 with an internal splitter plate 320. The splitter plate 320 further facilitates mixing through the ducts 230. Other components and configurations may be used herein.

[0025] Figure 9 shows a further example of a static mixer 210 with several inclined ducts 230. In this example, the inlet sidewall 250 and outlet sidewall 260 are positioned around the top of the outer shell 220. The number of ducts 230, the length of the ducts 230, and the angle of the ducts 230 may vary. Figure 10 shows a static mixer 210 with several inclined ducts 230 positioned in several rows 330, each row 330 having a different angle. Other components and configurations may be used herein.

[0026] The static mixer 210 described herein is for illustrative purposes only. Many other static mixer designs and configurations may be used herein, for example, depending on the size of each instrument, the desired overall pressure drop, and other types of performance objectives and parameters.

[0027] Therefore, the static mixer 210 achieves a flow of exhaust air 98 with a uniform concentration and temperature of leaked fuel gas 95 in the plane of the sampling tube 120. Such uniform concentration and temperature provide more reliable sensor readings regardless of the type of operational / leakage scenario. Furthermore, the static mixer 210 provides this reliability with a generally lower pressure drop. Moreover, such reliability can lead to a reduction in the total number of sensors that need to be used herein. Finally, overall plant operation and efficiency are promoted by reducing false alarms and unnecessary shutdowns. The static mixer 210 may be the original equipment or installed as a modification.

[0028] It is clear that the above pertains only to specific embodiments of this application and the resulting patent. Those skilled in the art can make numerous changes and modifications herein without departing from the general spirit and scope of the invention as defined by the following claims and equivalents.

[0029] Examples of clauses that may be used to describe this hazardous gas detection system and method include the following:

[0030] 1. A hazardous gas detection system for determining the concentration and temperature of hazardous gases in the exhaust airflow within an exhaust duct of a gas turbine compartment, comprising one or more sensors positioned within or in communication with the exhaust duct, and a static mixer positioned upstream of the one or more sensors to promote mixing of the exhaust airflow.

[0031] 2. The hazardous gas detection system described in the preceding clause, wherein the static mixer is positioned within the gas turbine compartment adjacent to the exhaust duct.

[0032] 3. The hazardous gas detection system described in any one of the preceding clauses, wherein the static mixer is positioned within the exhaust duct adjacent to the gas turbine compartment.

[0033] 4. The hazardous gas detection system according to any one of the preceding clauses, wherein the exhaust duct comprises an instrumentation duct equipped with one or more sensors, and the static mixer is positioned upstream of the instrumentation duct.

[0034] 5. The hazardous gas detection system according to any one of the preceding clauses, further comprising one or more sampling tubes positioned within the exhaust duct.

[0035] 6. The hazardous gas detection system according to any one of the preceding clauses, wherein the one or more sensors comprises hazardous gas sensors communicating with the one or more sampling tubes.

[0036] 7. The hazardous gas detection system according to any one of the preceding clauses, wherein the one or more sensors comprises thermocouples positioned around the one or more sampling tubes.

[0037] 8. The static mixer comprises an outer shell and a plurality of ducts, the hazardous gas detection system described in any one of the preceding clauses.

[0038] 9. The hazardous gas detection system according to any one of the preceding clauses, wherein the plurality of ducts comprises a pair of ducts positioned in a cross configuration.

[0039] 10. A hazardous gas detection system according to any one of the preceding clauses, wherein each of the plurality of ducts comprises an inlet wall and an outlet wall.

[0040] 11. The hazardous gas detection system according to any one of the preceding clauses, wherein each of the inlet wall and the outlet wall has a plurality of openings inside.

[0041] 12. A hazardous gas detection system according to any one of the preceding clauses, wherein each of the plurality of ducts is provided with a lateral side wall, and the lateral side wall is provided with a plurality of openings.

[0042] 13. A hazardous gas detection system according to any one of the preceding clauses, wherein each of the plurality of ducts is provided with a splitter plate inside.

[0043] 14. The hazardous gas detection system according to any one of the preceding clauses, wherein the plurality of ducts comprises a plurality of inclined ducts positioned in a plurality of rows.

[0044] 15. A method for determining the concentration or temperature of a harmful gas in an exhaust airflow within an exhaust duct of a gas turbine compartment, comprising the steps of: drawing the exhaust airflow into the exhaust duct; positioning a static mixer in the exhaust airflow; uniformly mixing the harmful gas in the exhaust airflow; and detecting the concentration or temperature of the harmful gas.

[0045] 16. A hazardous gas detection system for determining the concentration and temperature of hazardous gases in the exhaust airflow within an exhaust duct of a gas turbine compartment, comprising one or more gas sensors and one or more temperature sensors positioned within or in communication with the exhaust duct, and a static mixer positioned upstream of the one or more gas sensors and one or more temperature sensors to promote mixing of the exhaust airflow.

[0046] 17. The hazardous gas detection system described in the preceding clause, wherein the static mixer is positioned within the gas turbine compartment adjacent to the exhaust duct.

[0047] 18. The hazardous gas detection system according to either clause 16 or 17, wherein the static mixer is positioned within the exhaust duct adjacent to the gas turbine compartment.

[0048] 19. The hazardous gas detection system according to any one of Clauses 16, 17, or 18, wherein the exhaust duct comprises an instrumentation duct equipped with one or more gas sensors and one or more temperature sensors, and the static mixer is positioned upstream of the instrumentation duct.

[0049] 20. The hazardous gas detection system according to any one of the clauses 16 to 19, wherein the static mixer comprises an outer shell and a plurality of ducts, each of the plurality of ducts comprising one or more walls having a plurality of openings. [Explanation of Symbols]

[0050] 10 Gas turbine engines 15 Compressor 20 Air 25 Entrance Section 30 Combustor cans 32 Fuel 40 High-temperature combustion gases 45 Turbine 50 shaft 55 Generators 60 Exhaust Section 65 Gas Turbine Section 70 Ventilation System 75 Ventilation inlet duct 80 Ventilation and exhaust duct 85 Fans, blowers 90 Ventilated air 95 Fuel gas 98 Exhaust air 100 Hazardous Gas Detection Systems 110 Instrumentation duct 115 Sensor 120 sampling tubes 130 First air sampling tube 140 Second air sampling tube 150 temperature sampling tubes, temperature tubes 160 First air sampling port 170 Second air sampling port 180 Thermocouple 190 First gas sensor 200 Second gas sensor 210 Static Mixer 220 Outer shell 230 ducts, inclined ducts 240 Approximately rectangular shape 250 Side entrance wall 260 Side exit wall 270 Top wall 280 Bottom wall 290 Lateral side wall 300 aperture 310 Cross-offset configuration 320 Internal Splitter Plate 330 columns

Claims

1. A hazardous gas detection system (100) that determines the concentration and temperature of hazardous gases in the flow of exhaust air (98) in the exhaust duct (80) of a gas turbine compartment (65), wherein the hazardous gas detection system (100) One or more sensors (115) positioned within or in communication with the exhaust duct (80), A static mixer (210) positioned upstream of the one or more sensors (115) to promote mixing of the exhaust air (98) flow, The static mixer (210) comprises an outer shell (220) and a plurality of ducts (230), A hazardous gas detection system (100) wherein each of the plurality of ducts (230) is provided with an inlet wall (250) and an outlet wall (260), and each of the inlet wall (250) and the outlet wall (260) is provided with a plurality of openings (300) inside.

2. The hazardous gas detection system (100) according to claim 1, wherein the static mixer (210) is positioned within the gas turbine compartment (65) adjacent to the exhaust duct (80).

3. The hazardous gas detection system (100) according to claim 1, wherein the static mixer (210) is positioned within the exhaust duct (80) adjacent to the gas turbine compartment (65).

4. The hazardous gas detection system (100) according to claim 1, wherein the exhaust duct (80) comprises an instrumentation duct (110) equipped with one or more sensors (115), and the static mixer (210) is positioned upstream of the instrumentation duct (110).

5. The hazardous gas detection system (100) according to claim 1, further comprising one or more sampling tubes (120) positioned within the exhaust duct (80).

6. The hazardous gas detection system (100) according to claim 5, wherein the one or more sensors (115) comprises hazardous gas sensors (190, 200) that communicate with the one or more sampling tubes (120).

7. The hazardous gas detection system (100) according to claim 5, wherein the one or more sensors (115) comprises thermocouples (180) positioned around the one or more sampling tubes (120).

8. The hazardous gas detection system (100) according to claim 1, wherein the plurality of ducts (230) comprises a pair of ducts (230) positioned in a cross configuration (310).

9. The hazardous gas detection system (100) according to claim 1, wherein each of the plurality of ducts (230) is provided with a lateral side wall (290), and the lateral side wall (290) is provided with a plurality of openings (300).

10. The harmful gas detection system (100) according to claim 1, wherein each of the plurality of ducts (230) is provided with a splitter plate (320) inside.

11. The hazardous gas detection system (100) according to claim 1, wherein the plurality of ducts (230) comprises a plurality of inclined ducts (230) positioned in a plurality of rows (330).

12. A method for determining the concentration or temperature of harmful gases (95) in the flow of exhaust air (98) in the exhaust duct (80) of a gas turbine compartment (65), The steps include drawing the flow of the exhaust air (98) into the exhaust duct (80), A step of positioning a static mixer (210) in the flow of exhaust air (98), wherein the static mixer (210) comprises an outer shell (220) and a plurality of ducts (230), each of the plurality of ducts (230) comprising an inlet wall (250) and an outlet wall (260), and each of the inlet wall (250) and the outlet wall (260) comprising a plurality of openings (300) inside, The steps include uniformly mixing the harmful gas (95) in the flow of the exhaust air (98), A step of detecting the concentration or temperature of the harmful gas (95) Methods that include...

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