A gas turbine inter-stage steam injection system based on gas turbine waste heat utilization

Abstract

This invention belongs to the field of gas turbine waste heat utilization technology, and specifically relates to a gas turbine interstage steam injection system based on gas turbine waste heat utilization. This gas turbine interstage steam injection system includes a gas turbine system composed of a compressor, combustion chamber, turbine, and power turbine. Its key feature is that a steam generation system is connected between the tail end of the power turbine and the turbine; the end of the steam generation system is connected to a steam injection port; the steam injection port is connected to a first annular cavity; the first annular cavity is connected to a second annular cavity; the second annular cavity is connected to a guide vane; the guide vane is connected to the interior of the blade; and the blade has two rows of outflow holes on both the pressure and suction surfaces, which are connected to the main flow channel via a gas passage. The beneficial effect of this invention is that the steam injection flow path can be designed with minimal modification to the prototype turbine blades, thus improving the overall efficiency of the gas turbine.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine waste heat utilization technology, and specifically relates to a gas turbine stage steam injection system based on gas turbine waste heat utilization. Background Technology

[0002] A gas turbine is an internal combustion engine that uses a continuously flowing gas as its working fluid to drive a high-speed rotating impeller, converting the energy of fuel into useful work. It is a type of rotary turbine thermal engine. To improve the output power and efficiency of a gas turbine, steam injection is a feasible technology. Its principle involves superheated steam generated by a waste heat boiler being reinjected into the gas turbine's combustion chamber, where it mixes with compressed air, is heated to the turbine's initial temperature, and then expands together to perform work. Implementing steam injection often requires significant modifications to the gas turbine's combustion chamber, introducing large equipment such as waste heat boilers, resulting in a large footprint. Furthermore, careful attention must be paid to the airflow organization during steam injection to prevent steam from crowding out oxygen in the main combustion zone, leading to incomplete fuel combustion. This places high demands on the structural design of both the combustion chamber and the steam injection system. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, this invention provides a gas turbine stage steam injection system based on the utilization of waste heat from gas turbines.

[0004] This invention is achieved through the following technical solution: A gas turbine stage interstage steam injection system based on waste heat utilization of a gas turbine is characterized by comprising a gas turbine system consisting of a compressor, a combustion chamber, a turbine, and a power turbine. A steam generation system is connected between the tail end of the power turbine and the turbine. The end of the steam generation system is connected to a steam injection port. The steam injection port is connected to a first annular cavity. The first annular cavity is connected to a second annular cavity. The second annular cavity is connected to a guide vane. The guide vane is connected to the interior of the blade. The blade has two rows of outflow holes on both the pressure surface and the suction surface. The outflow holes are connected to the main flow channel through a gas passage.

[0005] A throttling orifice is provided between the first annular cavity and the second annular cavity.

[0006] The second annular cavity is located between the outer casing and the inner casing.

[0007] The blades are provided with steam injection holes and cooling channels.

[0008] The steam generation system includes a tailpipe connected to a power turbine, a tailpipe connected to an exhaust heat exchange pipe, a water pump and a pressure reducing valve connected to both ends of the exhaust heat exchange pipe, a pressure reducing valve connected to a separator tank, and a separator tank connected to the turbine via a three-way valve.

[0009] The three-way valve is connected to the air compressor.

[0010] The separation tank is connected to a water pump via a liquid water pipe.

[0011] The exhaust heat exchange pipe is connected to the liquid water pipe.

[0012] The exhaust heat exchange pipe is connected to the tail nozzle via a primary exhaust heat exchange pipe.

[0013] The separator is connected to a three-way valve via a primary exhaust heat exchange pipe.

[0014] The beneficial effects of this invention are: The steam injection flow path can be designed with minimal modifications to the prototype turbine blades. The injected steam can partially handle the secondary cooling of the air, reducing the amount of air drawn from the high-pressure stage of the compressor and improving the overall efficiency of the gas turbine. Utilizing the waste heat of the gas turbine, water vapor is generated through a flash evaporation system and injected into the gas turbine, improving the overall thermal efficiency of the gas turbine and reducing resource waste. The flash evaporation device has a smaller footprint, reducing the footprint of the original steam injection cycle. Attached Figure Description

[0015] The invention will now be further described with reference to the accompanying drawings.

[0016] Appendix Figure 1 This is a schematic diagram of the structure of the present invention; Appendix Figure 2 For the appendix Figure 1 Schematic diagram of the structure within the dashed line section; Appendix Figure 3 This is a schematic diagram of the blade structure of the present invention; Appendix Figure 4 This is a structural block diagram of the steam generation system of the present invention; In the figure, 1 is the steam inlet, 2 is the first annular cavity, 3 is the second annular cavity, 4 is the guide vane, 5 is the blade, 6 is the outlet hole, 7 is the gas passage, 8 is the main flow passage, 9 is the throttling orifice, 10 is the outer casing, 11 is the inner casing, 12 is the steam inlet, and 13 is the cooling passage. Detailed Implementation

[0017] The attached figure illustrates a specific embodiment of the present invention. This embodiment includes a gas turbine system consisting of a compressor, a combustion chamber, a turbine, and a power turbine. A steam generation system is connected between the tail end of the power turbine and the turbine. The end of the steam generation system is connected to a steam injection port 1. The steam injection port 1 is connected to a first annular cavity 2. The first annular cavity 2 is connected to a second annular cavity 3. The second annular cavity 3 is connected to a guide vane 4. The guide vane 4 is connected to the interior of a blade 5. The blade 5 has two rows of outflow holes 6 on both the pressure surface and the suction surface. The outflow holes 6 are connected to the main flow channel 8 through a gas passage 7.

[0018] A throttling orifice 9 is provided between the first annular cavity 2 and the second annular cavity 3. The second annular cavity 3 is located between the outer casing 10 and the inner casing 11. A steam injection hole 12 is provided on the blade 5, and a cooling channel 13 is provided on the blade 5.

[0019] The steam generation system includes a tailpipe connected to a power turbine, a tailpipe connected to an exhaust heat exchange pipe, an exhaust heat exchange pipe connected to a water pump and a pressure reducing valve at both ends, a pressure reducing valve connected to a separator tank, and a separator tank connected to the turbine via a three-way valve.

[0020] The three-way valve is connected to the compressor. The separator is connected to the water pump via a liquid water pipe. The exhaust heat exchange pipe is connected to the liquid water pipe. A primary exhaust heat exchange pipe connects the exhaust heat exchange pipe to the tailpipe. The separator is connected to the three-way valve via the primary exhaust heat exchange pipe.

[0021] The gas turbine stage steam injection system based on the utilization of waste heat from a gas turbine, as described in this invention, involves the high-temperature exhaust gas discharged from the tailpipe entering the primary exhaust heat exchange pipe for cooling and heat exchange. The discharged secondary exhaust gas also enters the exhaust heat exchange pipe. Low-temperature, low-pressure deionized water is supplied to the exhaust heat exchange pipe via a water pump to obtain high-pressure, high-temperature deionized water. After passing through a pressure reducing valve, the liquid water flashes to produce water and water vapor. The liquid water and water vapor are separated in a separation tank. The liquid water returns to the water pump through a liquid water pipe, while the water vapor enters the primary exhaust heat exchange pipe and is discharged as high-temperature water vapor. The high-temperature water vapor then enters the gas turbine through a three-way valve. Steam is injected into the first annular cavity 2 through steam injection port 1. When the unit is working, steam enters the cavity through the pipeline, then flows through the throttling orifice 9 on the casing into the second annular cavity 3 between the outer casing 10 and the inner casing 11 of the gas turbine. The steam in the cavity enters the blade 5 through the airflow passage inside the secondary guide vane 4. The blade body has two rows of outflow holes 6 on both the pressure and suction sides. After entering the inner cavity of the blade 5, the steam flows out through the outflow holes 6 into the gas passage 7 and mixes with the mainstream flow in the main flow passage 8, reducing the impact of steam injection on the mainstream flow field. Specifically, inside the blade 5, steam is injected into the mainstream through the ribbed cooling passage 13 and the steam injection holes 12 on the steam pressure side and suction side.

[0022] The energy source for the flash air atomization system is the exhaust gas from the gas turbine. This working fluid still has a high energy content that can be utilized. Utilizing this energy can improve the overall thermal efficiency of the gas turbine and reduce resource waste. The three-way valve switches the flow path to the cooling air side in the event of a flash system failure, reducing the impact on the gas turbine unit.

[0023] Introducing steam injection into the gas turbine interstage has minimal impact on the combustion chamber. Furthermore, the turbine stator blades are typically hollow to ensure turbine blade cooling and reduce weight, making the steam injection structure relatively simple to design. Simultaneously, it can handle some of the secondary cooling air; water vapor has a higher specific heat, resulting in a smaller temperature rise for the same amount of cooling air, reducing the amount of air drawn from the compressor's high-pressure stage and improving the overall efficiency of the gas turbine.

Claims

1. A gas turbine inter-stage steam injection system based on gas turbine waste heat utilization, characterized in that: The gas turbine system includes a compressor, a combustion chamber, a turbine and a power turbine. The power turbine is connected to the turbine by a steam generation system. The end of the steam generation system is connected to a steam injection port (1). The steam injection port (1) is connected to the first annular cavity (2). The first annular cavity (2) is connected to the second annular cavity (3). The second annular cavity (3) is connected to the guide vane (4). The guide vane (4) is connected to the inside of the blade (5). The blade (5) has two rows of outflow holes (6) on the pressure surface and the suction surface. The outflow holes (6) are connected to the main flow channel (8) through the gas passage (7).

2. The gas turbine inter-stage steam injection system based on gas turbine waste heat utilization according to claim 1, characterized in that: A throttling orifice (9) is provided between the first annular cavity (2) and the second annular cavity (3).

3. The gas turbine inter-stage steam injection system based on gas turbine waste heat utilization according to claim 1, characterized in that: The second annular cavity (3) is located between the outer casing (10) and the inner casing (11).

4. The gas turbine inter-stage steam injection system utilizing gas turbine waste heat according to claim 1, characterized in that: The blade (5) is provided with a steam injection hole (12) and a cooling channel (13).

5. The gas turbine inter-stage steam injection system utilizing gas turbine waste heat according to claim 1, characterized in that: The steam generation system includes a tailpipe connected to a power turbine, a tailpipe connected to an exhaust heat exchange pipe, a water pump and a pressure reducing valve connected to both ends of the exhaust heat exchange pipe, a pressure reducing valve connected to a separator tank, and a separator tank connected to the turbine via a three-way valve.

6. The gas turbine inter-stage steam injection system based on gas turbine waste heat utilization according to claim 5, characterized in that: The three-way valve is connected to the air compressor.

7. The gas turbine inter-stage steam injection system based on gas turbine waste heat utilization according to claim 5, characterized in that: The separation tank is connected to a water pump via a liquid water pipe.

8. The gas turbine inter-stage steam injection system utilizing gas turbine waste heat according to claim 5, characterized in that: The exhaust heat exchange pipe is connected to the liquid water pipe.

9. The gas turbine inter-stage steam injection system based on gas turbine waste heat utilization according to claim 5, characterized in that: The exhaust heat exchange pipe is connected to the tail nozzle via a primary exhaust heat exchange pipe.

10. The gas turbine inter-stage steam injection system based on gas turbine waste heat utilization according to claim 9, characterized in that: The separator is connected to a three-way valve via a primary exhaust heat exchange pipe.

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