Direct air cooling system

Abstract

The utility model relates to the technical field of direct air cooling systems, in particular to a direct air cooling system. The utility model provides a direct air cooling system which comprises an air cooling condenser, a steam exhaust pipeline, a condensation water header and a preheating mechanism. The air-cooled condenser comprises two groups of finned tube rows, the top ends of the two groups of finned tube rows are communicated with the steam exhaust pipeline, and the bottom ends of the two groups of finned tube rows are communicated with the condensed water header; one end of the preheating mechanism is communicated with the steam exhaust pipeline, and the other end of the preheating mechanism is communicated with the condensed water header. The preheating mechanism can be used for conveying saturated steam in the steam exhaust pipeline into the condensation water header so as to preheat the condensation water header, so that the temperature in the condensation water header can be obviously increased, and the condensation water discharged by the finned tube bundle cannot be frozen when entering the condensation water header; the anti-freezing purpose is achieved when the direct air cooling system is started, and the starting and stopping flexibility of a unit is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of direct air cooling systems, in particular to a direct air cooling system. Background Art

[0002] The direct air cooling system usually includes an axial flow fan, an air-cooled condenser, a condensate header, a connecting pipe and a vacuum system. The air-cooled condenser includes two groups of finned tube rows, the top ends of the two groups of finned tube rows are connected to the bottom of the steam distribution pipe, the two groups of finned tube rows are arranged obliquely and symmetrically about the steam distribution pipe, and an air duct cavity is formed between the two groups of finned tube rows, and the cross-section of the air duct cavity is triangular. Each group of finned tube rows includes a downstream tube bundle and a countercurrent tube bundle, the top end of the downstream tube bundle is connected to the steam distribution pipe, and the bottom end is connected to the condensate header, the bottom end of the countercurrent tube bundle is connected to the condensate header, and the bottom end is connected to the connecting pipe, and the axial flow fan is arranged in the center of the air duct cavity and close to the bottom of the air duct cavity. During operation, steam enters the finned pipe at the top of the downstream tube bundle through the steam distribution pipe, and the steam moves from the top to the bottom of the downstream tube bundle. The axial flow fan forces the cooling air to flow through the finned tube row. In the process of steam going down, most of the steam condenses through the downstream tube bundle to form condensed water, and the condensed water flows into the condensate header. The remaining steam and non-condensable gas flow upward from the condensate header into the countercurrent tube bundle. This part of the steam condenses in the countercurrent tube bundle in the reverse flow, while the non-condensable gas gathers near the top of the countercurrent tube bundle and is sucked into the connecting pipe connected to the countercurrent tube bundle. The connecting pipe is connected to the vacuum system to remove the non-condensable gas.

[0003] At present, the climate characteristics of the "Three Norths" (North China, Northeast China, and Northwest China) in my country are that the extreme maximum temperature is very high, generally around 40℃, and the extreme minimum temperature is very low, generally around -40℃. Therefore, in winter, the antifreeze performance of the unit is extremely important. In winter, when the direct air cooling system is just started, the temperature of the condensate header is very low, which will cause the condensate condensed from the fin tube row to enter the condensate header and freeze. Utility Model Content

[0004] (I) The problem to be solved by the present invention is that in winter, when the direct air cooling system is just started, the temperature of the condensate header is very low, so the condensate condensed by the finned tube row will enter the condensate header and freeze.

[0005] (II) Technical solution

[0006] A direct air cooling system comprises an air-cooled condenser, an exhaust pipe, a condensate header and a preheating mechanism;

[0007] The air-cooled condenser comprises two groups of finned tube rows, the top ends of the two groups of finned tube rows are connected to the exhaust pipe, and the bottom ends of the two groups of finned tube rows are connected to the condensate header;

[0008] One end of the preheating mechanism is connected to the exhaust pipe, and the other end thereof is connected to the condensate header, and is used to transport the saturated steam in the exhaust pipe to the condensate header to preheat the condensate header.

[0009] According to one embodiment of the utility model, the preheating mechanism includes at least one connecting pipe, one end of the connecting pipe is connected to the exhaust pipe, and the other end is connected to the condensate manifold, and each of the connecting pipes is installed with an isolation valve for controlling its on and off.

[0010] According to one embodiment of the utility model, one end of the connecting pipe is connected to the end of the condensate manifold, or one end of the connecting pipe is connected to the middle of the condensate manifold, or one end of the connecting pipe is connected to the rear of the condensate manifold.

[0011] According to an embodiment of the utility model, a plurality of the communicating pipes are provided.

[0012] According to an embodiment of the utility model, the direct air cooling system includes a steam exhaust device, one end of the steam exhaust pipe is connected to the steam exhaust device, and the steam exhaust device is connected to the low-pressure cylinder of the steam turbine.

[0013] Beneficial effects of the utility model:

[0014] The utility model provides a direct air cooling system, comprising an air-cooled condenser, an exhaust steam pipeline, a condensate header and a preheating mechanism; the air-cooled condenser comprises two groups of finned tube rows, the top ends of the two groups of finned tube rows are connected to the exhaust steam pipeline, and the bottom ends of the two groups of finned tube rows are connected to the condensate header; one end of the preheating mechanism is connected to the exhaust steam pipeline, and the other end is connected to the condensate header, and is used for conveying saturated steam in the exhaust steam pipeline to the condensate header to preheat the condensate header.

[0015] In winter, the outdoor temperature is very low, and the temperature in the condensate manifold is also very low. When the unit is started, in order to prevent the condensate in the condensate manifold from freezing, the preheating mechanism can be used to transport the saturated steam in the exhaust pipe to the condensate manifold to preheat the condensate manifold. This can significantly increase the temperature in the condensate manifold, so that the condensate discharged from the fin tube row will not freeze when entering the condensate manifold, thereby achieving the anti-freezing purpose when the direct air cooling system is started, greatly improving the flexibility of the unit's start-up and stopping, and solving the anti-freezing problem during the unit's startup phase under severe winter conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram provided for an embodiment of the utility model.

[0018] Icons: 1. Platform support column; 2. Finned tube row; 3. Condensate manifold; 4. Exhaust device; 5. Exhaust pipe; 6. Connecting pipe; 7. Isolation valve. DETAILED DESCRIPTION

[0019] The technical solution of the utility model will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] like Figure 1 As shown, an embodiment of the utility model provides a direct air cooling system, a direct air cooling system, including an air condenser, an exhaust pipe 5, a condensate header 3 and a preheating mechanism;

[0021] The air-cooled condenser comprises two groups of finned tube rows 2, the top ends of the two groups of finned tube rows 2 are connected to the exhaust pipe 5, and the bottom ends of the two groups of finned tube rows 2 are connected to the condensate header 3;

[0022] One end of the preheating mechanism is connected to the exhaust pipe 5 , and the other end thereof is connected to the condensate header 3 , and is used for conveying the saturated steam in the exhaust pipe 5 to the condensate header 3 to preheat the condensate header 3 .

[0023] In this embodiment, in winter, the outdoor temperature is very low, and the temperature in the condensate manifold 3 is also very low. When the unit is started, in order to prevent the condensate in the condensate manifold 3 from freezing, the preheating mechanism can be used to transport the saturated steam in the exhaust pipe 5 to the condensate manifold 3 to preheat the condensate manifold 3. This can significantly increase the temperature in the condensate manifold 3, so that the condensate discharged from the fin tube row 2 will not freeze when entering the condensate manifold 3, thereby achieving the anti-freezing purpose when the direct air cooling system is started, greatly improving the flexibility of the unit's start-up and stopping, and solving the anti-freezing problem during the unit's startup phase under severe winter conditions.

[0024] It should be noted that at normal temperature or in summer, when the outdoor temperature is high, the preheating mechanism is not needed. Only in the low temperature conditions in winter, the direct air cooling system will use the preheating mechanism when it is started. When the temperature of the condensate header 3 rises to a higher temperature to ensure that freezing does not occur, the preheating mechanism can be immediately turned off.

[0025] As a preferred embodiment, Figure 1 As shown, the preheating mechanism includes a connecting pipe 6 and an isolating valve 7. The connecting pipe 6 is provided with one, one end of the connecting pipe 6 is connected to the exhaust pipe 5, and the other end thereof is connected to the condensate manifold 3. The isolating valve 7 is installed on the connecting pipe 6 to control its on and off.

[0026] When the condensate header 3 needs to be preheated, the isolation valve 7 can be opened, and the saturated steam in the exhaust pipe 5 enters the condensate header 3 through the connecting pipe 6, thereby increasing the temperature of the condensate header 3 and preventing the condensate in the condensate header 3 from freezing. When the temperature in the condensate header 3 is raised to the set temperature and the condensate no longer freezes, the isolation valve 7 is immediately closed.

[0027] It should be noted that if Figure 1 As shown, one end of the connecting pipe 6 is connected to the side of the right end of the condensate header 3, and the other end is connected to the vertical part of the exhaust pipe 5. At this time, the length of the connecting pipe 6 is the shortest, and the saturated steam in the exhaust pipe 5 can be quickly transported to the condensate header 3 through the connecting pipe 6.

[0028] Optionally, one end of the communication pipe 6 is connected to the middle of the condensate header 3, that is, connected to the middle position of the length direction of the condensate header 3. In this way, the saturated steam in the exhaust pipe 5 can diffuse from the middle of the condensate header 3 to both sides to accelerate preheating.

[0029] Optionally, one end of the communication pipe 6 is connected to the rear of the condensate manifold 3 .

[0030] Preferably, the direct air cooling system includes a controller and at least one temperature sensor, the temperature sensor is arranged inside the condensate manifold 3 to detect the internal temperature of the condensate manifold 3, the temperature sensor is connected to the controller signal, and the isolation valve 7 is an electric isolation valve, which is connected to the controller signal.

[0031] The temperature sensor sends a temperature signal to the controller, which determines the temperature value. When the temperature value is lower than the set value, the controller controls the isolation valve 7 to open, so that the saturated steam in the exhaust pipe 5 enters the condensate header 3 through the connecting pipe 6. When the temperature value is higher than the set value, the controller controls the isolation valve 7 to close. In this way, automatic preheating can be achieved with high working efficiency.

[0032] As an optional embodiment, a plurality of connecting pipes 6 are provided, a plurality of connecting holes are sequentially opened on the condensate manifold 3 along its length direction, a plurality of mounting holes are sequentially opened on the exhaust pipe 5 along its length direction, the first ends of the plurality of connecting pipes 6 are respectively connected to the plurality of connecting holes, the second ends of the plurality of connecting pipes 6 are respectively connected to the plurality of mounting holes, and an isolation valve 7 is installed on each connecting pipe 6.

[0033] In this way, when the condensate manifold 3 needs to be preheated, the isolation valves 7 on the multiple interconnecting pipes 6 can be opened at the same time, so that the saturated steam in the exhaust pipe 5 can enter the condensate manifold 3 through the multiple interconnecting pipes 6, thereby quickly increasing the temperature of the condensate manifold 3 and preventing the condensate in the condensate manifold 3 from freezing.

[0034] Specifically, three connecting pipes 6 are provided, among which the first end of one connecting pipe 6 is connected to the end of the condensate manifold 3 close to the left side, the first end of one connecting pipe 6 is connected to the middle position of the condensate manifold 3, and the first end of the last connecting pipe 6 is connected to the right end of the condensate manifold 3. The second ends of these three connecting pipes 6 are arranged in sequence along the length direction of the exhaust pipe 5 and are connected to the exhaust pipe 5. In this way, in winter, the outdoor temperature is very low. When the unit is started, in order to prevent the condensate in the condensate manifold 3 from freezing, the isolation valves 7 on the three connecting pipes 6 are opened to transport the saturated steam in the exhaust pipe 5 to the condensate manifold 3 to preheat the condensate manifold 3. Since there are three connecting pipes 6, the saturated steam can enter from the left end, the middle position and the right end of the condensate manifold 3 at the same time, so that the saturated steam can evenly cover the internal space of the condensate manifold 3, thereby quickly increasing the temperature in the condensate manifold 3, so that the condensate discharged from the fin tube row 2 will not freeze when entering the condensate manifold 3, thereby achieving the anti-freezing purpose when the direct air cooling system is started.

[0035] As a preferred embodiment, the direct air cooling system includes a condensate tank, a connecting pipe and a vacuum system. The fin tube row 2 includes a downstream condensate tube bundle and a countercurrent condensate tube bundle. The downstream condensate tube bundle and the countercurrent condensate tube bundle are arranged in sequence. The top of the countercurrent condensate tube bundle is connected to the connecting pipe, and the connecting pipe is connected to the vacuum system. The condensate tank and the condensate manifold 3 are connected by a pipeline.

[0036] Steam enters the finned pipe at the top of the downstream condensation tube bundle through the exhaust pipe 5. Steam moves from the top of the downstream condensation tube bundle to its bottom. The axial flow fan forces the cooling air to flow through the downstream condensation tube bundle. In the process of steam going down, most of the steam condenses through the downstream condensation tube bundle to form condensed water, and the condensed water flows into the condensation water header 3. The remaining steam and non-condensable gas flow upward from the condensation water header 3 into the countercurrent condensation tube bundle. This part of the steam condenses in the countercurrent condensation tube bundle in the reverse flow, while the non-condensable gas gathers near the top of the countercurrent condensation tube bundle and is sucked into the connecting pipe connected to the countercurrent condensation tube bundle. The connecting pipe is connected to the vacuum system, and the vacuum system removes the non-condensable gas through the connecting pipe. The condensed water collected in the condensation water header 3 is discharged into the condensation water tank through the pipeline.

[0037] As a preferred embodiment, Figure 1 As shown, the direct air cooling system includes an exhaust device 4, one end of an exhaust pipe 5 is connected to the exhaust device 4, and the exhaust device 4 is connected to the low-pressure cylinder of the steam turbine. Exhaust steam discharged from the low-pressure cylinder of the steam turbine enters the exhaust device 4 and is then transported to the downstream condensation tube bundle by the exhaust pipe 5.

[0038] It should be noted that if Figure 1 As shown, the direct air cooling system includes a platform support column 1 and a plurality of axial flow fans. The plurality of axial flow fans are evenly arranged along the length direction of the platform support column 1. Two groups of fin tube rows 2 are arranged on the platform support column 1. A triangular prism-shaped air duct cavity is formed between the two groups of fin tube rows 2 and the upper surface of the platform support column 1. The axial flow fan is located in the air duct cavity. The axial flow fan is used to blow cold air to the fin tube rows 2.

[0039] In the description of the present invention, it should be noted that the terms "upper" and "lower" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the insides of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A direct air cooling system, characterized in that: It comprises an air-cooled condenser, an exhaust pipe (5), a condensate header (3) and a preheating mechanism; The air-cooled condenser comprises two groups of finned tube rows (2), the top ends of the two groups of finned tube rows (2) are connected to the exhaust pipe (5), and the bottom ends of the two groups of finned tube rows (2) are connected to the condensate header (3); One end of the preheating mechanism is connected to the exhaust steam pipe (5), and the other end is connected to the condensate manifold (3), and is used to transport the saturated steam in the exhaust steam pipe (5) to the condensate manifold (3) to preheat the condensate manifold (3).

2. A direct air cooling system according to claim 1, characterized in that: The preheating mechanism comprises at least one connecting pipe (6), one end of which is connected to the exhaust pipe (5), and the other end of which is connected to the condensate manifold (3), and each connecting pipe (6) is provided with an isolation valve (7) for controlling its on and off.

3. A direct air cooling system according to claim 2, characterized in that: One end of the connecting pipe (6) is connected to the end of the condensate manifold (3), or one end of the connecting pipe (6) is connected to the middle of the condensate manifold (3), or one end of the connecting pipe (6) is connected to the rear of the condensate manifold (3).

4. A direct air cooling system according to claim 2, characterized in that: The communicating pipes (6) are provided in plurality.

5. A direct air cooling system according to claim 1, characterized in that: The direct air cooling system comprises a steam exhaust device (4), one end of the steam exhaust pipe (5) is connected to the steam exhaust device (4), and the steam exhaust device (4) is connected to the low-pressure cylinder of the steam turbine.

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