A ccpp nitrogen system

Abstract

The utility model provides a kind of CCPP nitrogen system, comprising: gas supply mechanism, gas supply mechanism has first nitrogen gas inlet end and first nitrogen gas outlet end, nitrogen gas can enter from first nitrogen gas inlet end and discharge from first nitrogen gas outlet end;Anti-corrosion mechanism, anti-corrosion mechanism has second nitrogen gas inlet end, second nitrogen gas inlet end can receive the nitrogen gas discharged by first nitrogen gas outlet end;Partition mechanism, partition mechanism is connected with first nitrogen gas outlet end and second nitrogen gas inlet end, partition mechanism can prevent the medium in anti-corrosion mechanism from entering into first nitrogen gas outlet end from second nitrogen gas inlet end, the utility model does not need to open nitrogen gas system blowdown door to drain water periodically, completely eliminates the medium in anti-corrosion mechanism to enter nitrogen gas system, will not affect the purging of air filter and the action of pneumatic valve, will not affect the stable operation of CCPP, simultaneously, eliminate the security risk that nitrogen gas leaks when nitrogen gas system drains.

Description

Technical Field

[0001] This utility model relates to the field of gas-steam combined cycle generator sets, and in particular to a CCPP nitrogen system. Background Technology

[0002] Every time a CCPP (Combined Cycle Power Plant) is shut down for a period of time, the waste heat boiler must be purged with nitrogen for corrosion prevention. During nitrogen purging, the relevant nitrogen valves on the waste heat boiler must be operated. However, during CCPP operation, damage to the air filter's coarse filter element may be found, indicating water in the purging nitrogen. This usually occurs because the high-pressure feedwater pressure is very high, typically around 10 MPa. After operating the corrosion prevention valves, the valves' tightness deteriorates, allowing water to enter the CCPP nitrogen system. Since nitrogen cannot be interrupted during CCPP operation, only temporary measures are taken, such as periodically opening the nitrogen system's drain valve to drain water. During this draining process, nitrogen is still released, posing a safety hazard. Utility Model Content

[0003] The purpose of this invention is to provide a CCPP nitrogen system that prevents the medium inside the anti-corrosion mechanism from entering the nitrogen system.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a CCPP nitrogen system, comprising: a gas supply mechanism having a first nitrogen inlet and a first nitrogen outlet, wherein nitrogen can enter from the first nitrogen inlet and exit from the first nitrogen outlet; an anti-corrosion mechanism having a second nitrogen inlet capable of receiving nitrogen discharged from the first nitrogen outlet; and an isolation mechanism connected to the first nitrogen outlet and the second nitrogen inlet, wherein the isolation mechanism can prevent the medium in the anti-corrosion mechanism from entering the first nitrogen outlet from the second nitrogen inlet.

[0005] Furthermore, the gas supply mechanism includes a gas supply main pipe, which is equipped with a first nitrogen valve. One end of the gas supply main pipe is the first nitrogen inlet, and the other end of the gas supply main pipe is the first nitrogen outlet.

[0006] Furthermore, the gas supply mechanism also includes a first gas supply branch pipe, a second gas supply branch pipe, a second nitrogen valve, and a third nitrogen valve. The main gas supply pipe is connected to the pneumatic valve operating system through the first gas supply branch pipe, and the main gas supply pipe is connected to the air filter coarse filter backflushing system through the second gas supply branch pipe.

[0007] Furthermore, the anti-corrosion mechanism includes a main pipe, one end of which is connected to the high-pressure coil, the low-pressure coil, the deaerator, and the high-pressure water supply device, and the other end of which is the second nitrogen inlet.

[0008] Furthermore, a first valve and a check valve are provided between the high-pressure transformer and the main pipe, between the low-pressure transformer and the main pipe, between the deaerator and the main pipe, and between the high-pressure water supply device and the main pipe.

[0009] Furthermore, the isolation mechanism includes a second valve and a plug, with the second nitrogen inlet, the second valve, the plug, and the first nitrogen outlet connected in sequence.

[0010] Furthermore, both the second nitrogen inlet and the first nitrogen outlet are provided with connecting flanges, one end of the second valve is connected to the connecting flange on the second nitrogen inlet, and the plug is detachably connected to the connecting flange on the second valve and the first nitrogen outlet.

[0011] Furthermore, the blocking plate is a steel plate, and the thickness of the blocking plate is not less than 3mm.

[0012] Furthermore, the anti-corrosion mechanism includes a drain pipe connected to the main pipe, and the drain pipe is equipped with a drain valve for controlling the opening and closing of the drain pipe.

[0013] Analysis shows that this utility model discloses a CCPP nitrogen system. This utility model eliminates the need to periodically open the nitrogen system drain valve to release water, completely preventing the medium in the anti-corrosion mechanism from entering the nitrogen system. It will not affect the purging of the air filter and the operation of the pneumatic valve, nor will it affect the stable operation of the CCPP. At the same time, it eliminates the safety hazard of nitrogen leakage when the nitrogen system is drained. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. Wherein: Figure 1 A schematic diagram of the structure of an embodiment of this utility model.

[0015] Explanation of reference numerals in the attached diagram: 1. First nitrogen valve; 2. Check valve; 3. First valve; 4. Blocking plate; 5. Second valve; 6. Second nitrogen valve; 7. Third nitrogen valve; 8. Drain pipe. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation of the present invention and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present invention without departing from the scope or spirit of the invention. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present invention encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0017] In the description of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and do not require that this utility model be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. The terms "connected," "linked," and "set up" used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a direct connection or an indirect connection through intermediate components; a wired connection, a radio connection, or a wireless communication signal connection. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0018] The accompanying drawings illustrate one or more examples of the present invention. The detailed description uses numerals and letters to refer to features in the drawings. Similar or analogous reference numerals in the drawings and description have been used to refer to similar or analogous parts of the present invention. As used herein, the terms “first,” “second,” “third,” and “fourth,” etc., are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of a single component.

[0019] like Figure 1 As shown, according to an embodiment of the present invention, a CCPP nitrogen system is provided, comprising: A gas supply mechanism having a first nitrogen inlet and a first nitrogen outlet, wherein nitrogen can enter from the first nitrogen inlet and exit from the first nitrogen outlet; a corrosion protection mechanism having a second nitrogen inlet, wherein the second nitrogen inlet can receive nitrogen discharged from the first nitrogen outlet; and a blocking mechanism connected to the first nitrogen outlet and the second nitrogen inlet, wherein the blocking mechanism can prevent the medium in the corrosion protection mechanism from entering the first nitrogen outlet from the second nitrogen inlet.

[0020] The core of this system consists of three mechanisms: a gas supply mechanism, a corrosion protection mechanism, and an isolation mechanism. The gas supply mechanism receives and distributes external nitrogen, with the gas channel between the first nitrogen inlet and outlet forming the main nitrogen supply path. The corrosion protection mechanism is designed for process equipment requiring nitrogen protection, such as waste heat boilers. It has a second nitrogen inlet to receive nitrogen from the gas supply mechanism and distribute it to various equipment points. The isolation mechanism physically connects the first nitrogen outlet of the gas supply mechanism to the second nitrogen inlet of the corrosion protection mechanism. This isolation mechanism establishes a reliable physical barrier between the first nitrogen outlet and the second nitrogen inlet, actively preventing backflow of the medium within the corrosion protection mechanism under user control. Specifically, it prevents the medium flowing from the second nitrogen inlet from flowing back into the first nitrogen outlet and even the entire gas supply mechanism. This unidirectional isolation design fundamentally eliminates the risk path of backflow contamination.

[0021] For example, if a large number of pneumatic valves using nitrogen as a gas source malfunction, the CCPP (Power Capacitor) can only be shut down for repair. It takes at least 8 hours for the CCPP to restart from shutdown, and these 8 hours affect the power generation efficiency: the rated power of the CCPP is 137.6MW = 137.6 × 106kW. It can be seen that this utility model can significantly reduce the losses caused by malfunctions.

[0022] Specifically, the gas supply mechanism includes a main gas supply pipe, on which a first nitrogen valve 1 is installed. One end of the main gas supply pipe is the first nitrogen inlet, and the other end is the first nitrogen outlet. To control the on / off state and regulate the flow rate of the main gas supply pipe, the first nitrogen valve 1 is installed on the pipe. This first nitrogen valve 1 is typically a gate valve, ball valve, or other valve type with good sealing performance. By operating the first nitrogen valve 1, the user can open or close the nitrogen supply to the entire system, or regulate the flow rate when necessary.

[0023] Specifically, the gas supply mechanism includes a first gas supply branch pipe, a second gas supply branch pipe, a second nitrogen valve 6, and a third nitrogen valve 7. The main gas supply pipe is connected to the pneumatic valve operating system via the first gas supply branch pipe, and the main gas supply pipe is connected to the air filter coarse filter backflushing system via the second gas supply branch pipe. The gas supply mechanism not only supplies gas to the corrosion protection mechanism but also meets the nitrogen needs of other important systems in the unit. The first gas supply branch pipe extends from the main gas supply pipe, and its end connects to the unit's pneumatic valve operating system. CCPP units extensively use pneumatically driven valves, which rely on stable, clean nitrogen as a power source. The dedicated supply line via the first gas supply branch pipe ensures stable gas quality and pressure for pneumatic valve operation. The second nitrogen valve 6 is installed on the first gas supply branch pipe for independent control of this nitrogen supply line. The second gas supply branch pipe also extends from the main gas supply pipe, and its end connects to the air filter coarse filter backflushing system. The air filter of the gas turbine intake system needs to be backflushed with high-pressure gas periodically during operation to maintain filtration efficiency. The third nitrogen valve 7 is installed on the second gas supply branch pipe and is used to control the flow of nitrogen in this line.

[0024] Specifically, the corrosion protection mechanism includes a main pipe, one end of which is connected to the high-pressure coil, low-pressure coil, deaerator, and high-pressure water supply device, and the other end of which is the second nitrogen inlet. This claim defines the specific structure of the corrosion protection mechanism. The core component of the corrosion protection mechanism is a main pipe. This main pipe acts as a nitrogen distribution manifold in the system. The main pipe is connected to multiple high-pressure coils, low-pressure coils, deaerators, and high-pressure water supply devices requiring nitrogen protection via branch pipes.

[0025] It is understandable that during the shutdown or standby period of thermal equipment, the internal spaces of the high-pressure coil, low-pressure coil, deaerator, and high-pressure feedwater device are prone to oxygen corrosion if exposed to air. Injecting nitrogen gas at a certain pressure into these devices forms an inert gas covering layer, which effectively isolates oxygen and prevents corrosion of metal components. The second nitrogen inlet is the main nitrogen inlet of the corrosion protection mechanism, connected to the aforementioned isolation mechanism, and receives nitrogen from the gas supply mechanism. After entering the main pipe from the second nitrogen inlet, the nitrogen is distributed to the high-pressure coil, low-pressure coil, deaerator, and high-pressure feedwater device through various branch pipes.

[0026] Specifically, the anti-corrosion mechanism includes a drain pipe 8, which is connected to the main pipe. The drain pipe 8 is equipped with a drain valve that controls the opening and closing of the drain pipe 8. The drain pipe 8 is connected to the main pipe, and the accumulated material in the main pipe is discharged through the drain pipe 8.

[0027] Specifically, a first valve 3 and a check valve 2 are installed between the high-pressure transformer and the main pipe, between the low-pressure transformer and the main pipe, between the deaerator and the main pipe, and between the high-pressure water supply device and the main pipe. An identical valve combination is installed on the connecting pipes between the high-pressure transformer and the main pipe, the low-pressure transformer and the main pipe, the deaerator and the main pipe, and the high-pressure water supply device and the main pipe. This combination includes at least one first valve 3 and one check valve 2. The first valve 3 is typically a manual or electric valve, installed near the main pipe. This allows for the on / off control of the nitrogen supply to that route. When nitrogen purging is required for a specific piece of equipment, its corresponding first valve 3 is opened; when the equipment needs to be put into operation or undergo maintenance, the valve is closed to isolate it from other systems. The check valve 2 is installed downstream of the first valve 3, closer to the protected equipment. The check valve 2 strictly prevents the medium from flowing back from the equipment side to the main pipe side. Even if the pressure inside a piece of equipment is higher than the pressure in the main pipe, or if the medium inside the equipment flows back for some reason, the check valve 2 will automatically close, forming a reliable barrier to prevent the medium from contaminating the main pipe and even the entire nitrogen system.

[0028] Specifically, the isolation mechanism includes a second valve 5 and a plug plate 4. The second nitrogen inlet, the second valve 5, the plug plate 4, and the first nitrogen outlet are connected in sequence. The isolation mechanism consists of two key components: the second valve 5 and the plug plate 4. They are connected in series in a specific order on the connecting pipeline between the gas supply mechanism and the corrosion protection mechanism. The specific connection sequence can be: starting from the corrosion protection mechanism side, the second nitrogen inlet, the second valve 5, the plug plate 4, and finally connected to the first nitrogen outlet of the gas supply mechanism. The second valve 5 acts as the main isolation valve here. During normal system operation, the second valve 5 is in the open state, and nitrogen can pass through smoothly. When it is necessary to completely isolate the gas supply mechanism from the corrosion protection mechanism, the second valve 5 can be closed, thereby cutting off the gas path. This is an active and operable isolation method. The plug plate 4 provides an additional, more thorough physical isolation barrier. The plug plate 4 is a solid plate-shaped component, usually inserted between two flanges. When the second valve 5 is closed, the plug plate 4 can be installed if long-term isolation is required. The presence of the plug plate 4 means that the pipeline is completely sealed off at its installation location, preventing any medium from passing through and achieving absolutely reliable isolation. This dual isolation measure of valve and plug plate 4 greatly enhances the system's safety level.

[0029] Specifically, the second nitrogen inlet and the first nitrogen outlet are equipped with connecting flanges. One end of the second valve 5 is connected to the connecting flange on the second nitrogen inlet. The plug plate 4 is detachably connected to the connecting flanges on the second valve 5 and the first nitrogen outlet. To ensure reliable installation of the second valve 5 and the plug plate 4, connecting flanges are provided at the pipe openings of both the second nitrogen inlet and the first nitrogen outlet. The second valve 5 itself also has a flange. One end of its flange is bolted to the connecting flange on the second nitrogen inlet pipe, with a gasket inserted in between to ensure a seal. In this way, the second valve 5 is securely installed at the inlet of the corrosion protection mechanism. The plug plate 4 is clamped between the other end flange of the second valve 5 and the connecting flange on the first nitrogen outlet pipe. When a normal airflow channel needs to be established, the plug plate 4 is removed, and the outlet flange of the second valve 5 is directly connected to the flange of the first nitrogen outlet and tightened. When absolute isolation is required by installing the plug plate 4, the flanges are disassembled, the plug plate 4 is inserted between them, and then the flanges and the plug plate 4 are tightened together with bolts. The plug plate 4 is usually also equipped with holes corresponding to the flange bolt holes. This flange-based connection method is highly standardized, easy to disassemble and assemble, and has good sealing performance, making it very suitable for occasions that require periodic isolation operations.

[0030] Preferably, the blocking plate is a steel plate with a thickness of not less than 3 mm. The blocking plate 4 is preferably made of steel plate. The choice of steel is primarily based on its sufficient mechanical strength and rigidity to withstand the pressure difference that may exist on both sides of the pipeline without deformation or cracking, ensuring absolute reliability of the isolation. Furthermore, the thickness of the blocking plate being not less than 3 mm is a key factor determining the pressure-bearing capacity and structural integrity of the blocking plate 4. Sufficient thickness ensures that the blocking plate 4 will not experience significant bending stress or shear failure when subjected to the maximum possible pressure difference in the system.

[0031] As can be seen from the above description, the above embodiments of this utility model achieve the following technical effects: This utility model does not require periodically opening the nitrogen system drain valve to release water, completely preventing the medium in the anti-corrosion mechanism from entering the nitrogen system, will not affect the purging of the air filter and the operation of the pneumatic valve, will not affect the stable operation of the CCPP, and at the same time, eliminates the safety hazard of nitrogen leakage when the nitrogen system is drained.

[0032] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A CCPP nitrogen system, characterized in that, include: A gas supply mechanism having a first nitrogen inlet and a first nitrogen outlet, wherein nitrogen can enter from the first nitrogen inlet and exit from the first nitrogen outlet; The corrosion protection mechanism has a second nitrogen inlet end, which is capable of receiving nitrogen discharged from the first nitrogen outlet end. A partition mechanism is provided, which is connected to the first nitrogen outlet and the second nitrogen inlet. The partition mechanism is capable of preventing the medium in the anti-corrosion mechanism from entering the first nitrogen outlet from the second nitrogen inlet.

2. The CCPP nitrogen system according to claim 1, characterized in that, The gas supply mechanism includes a gas supply main pipe, which is equipped with a first nitrogen valve. One end of the gas supply main pipe is the first nitrogen inlet, and the other end of the gas supply main pipe is the first nitrogen outlet.

3. A CCPP nitrogen system according to claim 2, characterized in that, The gas supply mechanism further includes a first gas supply branch pipe, a second gas supply branch pipe, a second nitrogen valve, and a third nitrogen valve. The main gas supply pipe is connected to the pneumatic valve operating system through the first gas supply branch pipe, and the main gas supply pipe is connected to the air filter coarse filter backflushing system through the second gas supply branch pipe.

4. A CCPP nitrogen system according to claim 1, characterized in that, The corrosion protection mechanism includes a main pipe, one end of which is connected to the high-pressure transformer, the low-pressure transformer, the deaerator and the high-pressure water supply device, and the other end of which is the second nitrogen inlet.

5. A CCPP nitrogen system according to claim 4, characterized in that, A first valve and a check valve are provided between the high-pressure transformer and the main pipe, between the low-pressure transformer and the main pipe, between the deaerator and the main pipe, and between the high-pressure water supply device and the main pipe.

6. A CCPP nitrogen system according to claim 1, characterized in that, The isolation mechanism includes a second valve and a plug, with the second nitrogen inlet, the second valve, the plug and the first nitrogen outlet connected in sequence.

7. A CCPP nitrogen system according to claim 6, characterized in that, Both the second nitrogen inlet and the first nitrogen outlet are provided with connecting flanges. One end of the second valve is connected to the connecting flange on the second nitrogen inlet. The plug is detachably connected to the connecting flange on the second valve and the first nitrogen outlet.

8. A CCPP nitrogen system according to claim 6, characterized in that, The blocking plate is made of steel plate, and the thickness of the blocking plate is not less than 3mm.

9. A CCPP nitrogen system according to claim 5, characterized in that, The anti-corrosion mechanism includes a drain pipe connected to the main pipe, and a drain valve is provided on the drain pipe to control the opening and closing of the drain pipe.

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