Heat exchange system and thermal power plant system

Abstract

The utility model relates to a heat exchange system and a thermal power plant system.The heat exchange system comprises a liquid storage box, a mixing box body, a second connecting pipe, a first heat exchange pipeline and a second heat exchange pipeline, and the mixing box body is connected with the liquid storage box; the second connecting pipe is connected to the mixing box body; the first heat exchange pipeline is used for being connected to a closed water pipeline in parallel in an on-off mode. The second heat exchange pipeline is connected to the mixing box and used for conveying a cooling medium, and at least part of the second heat exchange pipeline is located in the first heat exchange pipeline. According to the heat exchange system, when the open type water system breaks down, liquid nitrogen in the liquid storage box enters the mixing box body and is mixed with air in the mixing box body to form cooling gas, and on the basis, the cooling gas can conduct heat exchange operation with closed type water located in the first heat exchange pipeline through the second heat exchange pipeline; the temperature of closed water in the closed water pipeline is reduced, so that it is guaranteed that the closed water can cool equipment in the thermal power plant, and the thermal power plant can maintain the normal operation state.

Description

Technical Field

[0001] The present disclosure relates to the field of heat exchange technology, and in particular, to a heat exchange system and a thermal power plant system. Background Art

[0002] Most of the equipment in a thermal power plant needs to be cooled by a closed water system to ensure the normal operation of the equipment. Therefore, the closed water system is particularly important in a thermal power plant. Once the cooling system used for cooling fails, the closed water system will not be able to cool the equipment in the unit in time, resulting in the generator set tripping or even equipment damage.

[0003] At present, the closed water system in the thermal power plant is cooled by the open water system. However, the open water system may have the problem that the auxiliary pump trips while the standby pump is not started, so that the open water system cannot cool the closed water system, which may lead to the accident of non-shutdown of the unit and affect the normal operation of the thermal power plant. Utility Model Content

[0004] The purpose of the present disclosure is to provide a heat exchange system and a thermal power plant system, wherein the heat exchange system can serve as a backup system for an open water system to cool a closed water system, so as to at least partially solve the above technical problems.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present disclosure provides a heat exchange system for a closed water pipeline, comprising: a liquid storage tank for storing liquid nitrogen; a mixing box connected to the liquid storage tank for mixing the liquid nitrogen with air to form a cooling medium; a second connecting pipe connected to the mixing box in a switchable manner and used to input air into the mixing box; a first heat exchange pipeline for being switchably connected in parallel to the closed water pipeline; and a second heat exchange pipeline connected to the mixing box and used to transport the cooling medium, at least a portion of the second heat exchange pipeline being located in the first heat exchange pipeline.

[0006] Optionally, the second heat exchange pipeline includes a delivery pipeline, an inlet header, an outlet header and a plurality of branch pipes arranged in parallel and at least partially located in the first heat exchange pipeline, the delivery pipeline is respectively connected to one end of the inlet header and the mixing box, and both ends of the branch pipe are respectively connected to the other end of the inlet header and the outlet header.

[0007] Optionally, a drain pipeline is provided at the bottom of the mixing box and / or the outlet header.

[0008] Optionally, the delivery pipeline is provided with an induced draft fan for guiding the cooling medium to move along the second heat exchange pipeline.

[0009] Optionally, temperature measuring elements are provided on the delivery pipeline and the outlet header.

[0010] Optionally, there are multiple liquid storage tanks, and the multiple liquid storage tanks are arranged in parallel and are connected to the mixing box body in an on-off manner through a first connecting pipe.

[0011] Optionally, the first connecting pipe and / or the second connecting pipe is provided with an electric regulating valve for regulating the flow of the medium.

[0012] Optionally, the heat exchange system further comprises a compressed air pipeline which is switchably connected to the mixing box.

[0013] According to a second aspect of the present disclosure, a thermal power plant system is provided, comprising an open water system, a closed water pipeline and the above-mentioned heat exchange system, wherein the open water system is arranged in parallel with the closed water pipeline and is connected to the closed water pipeline in an on-off manner through another first heat exchange pipeline in the open water system; or, the open water system comprises an open water pipeline, and the open water pipeline is connected to the second heat exchange pipeline in an on-off manner.

[0014] Optionally, the closed water pipeline is connected to the first heat exchange pipeline in an on-off manner via a third connecting pipe, and two third connecting pipes are provided, and the two third connecting pipes are arranged at intervals along the extension direction of the closed water pipeline.

[0015] Through the above technical scheme, the heat exchange system disclosed in the present invention can allow the liquid nitrogen in the liquid storage tank to enter the mixing box and mix with the air in the mixing box to form cooling gas when the open water system fails. Based on this, the cooling gas can perform heat exchange operations with the closed water located in the first heat exchange pipeline through the second heat exchange pipeline to reduce the temperature of the closed water in the closed water pipeline, thereby ensuring that the closed water can cool the equipment in the thermal power plant, so that the thermal power plant can maintain normal operation.

[0016] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0018] Figure 1 It is a structural diagram of the heat exchange system provided in an embodiment of the present disclosure.

[0019] Description of Reference Numerals

[0020] 1-liquid storage tank; 2-mixing box; 3-first heat exchange pipeline; 4-second heat exchange pipeline; 401-transmission pipeline; 402-inlet header; 403-outlet header; 404-diversion pipe; 5-drain pipeline; 6-induced draft fan; 7-temperature measuring element; 8-first connecting pipe; 9-second connecting pipe; 10-electric regulating valve; 11-compressed air pipeline; 12-closed water pipeline; 13-third connecting pipe. DETAILED DESCRIPTION

[0021] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0022] In the present disclosure, unless otherwise specified, directional words such as "inside" and "outside" refer to "inside" and "outside" relative to the corresponding component's own contour. In addition, the terms "first", "second", "third", etc. used in the present disclosure are to distinguish one element from another and do not have order and importance. In addition, in the following description, when referring to the drawings, unless otherwise explained, the same figure numbers in different drawings represent the same or similar elements. The above definitions are only used to explain and illustrate the present disclosure and should not be understood as limitations on the present disclosure.

[0023] The heat exchange system in an exemplary embodiment of the present disclosure will be described below with reference to the accompanying drawings.

[0024] refer to Figure 1As shown, in the first aspect of the present disclosure, a heat exchange system is provided, which is used for a closed water pipeline 12, comprising a liquid storage tank 1, a mixing box 2, a second connecting pipe 9, a first heat exchange pipeline 3 and a second heat exchange pipeline 4, wherein the liquid storage tank 1 is used to store liquid nitrogen; the mixing box 2 is connected to the liquid storage tank 1, and is used to mix liquid nitrogen with air to form a cooling medium; the second connecting pipe 9 can be connected to the mixing box 2 in an on-off manner, and is used to input air into the mixing box 2; the first heat exchange pipeline 3 is used to be connected in parallel to the closed water pipeline 12 in an on-off manner; the second heat exchange pipeline 4 is connected to the mixing box 2 and is used to transport the cooling medium, and at least part of the second heat exchange pipeline 4 is located in the first heat exchange pipeline 3. The heat exchange system of the present invention is started when the open water system of the thermal power plant has problems and cannot work. The liquid nitrogen in the liquid storage tank 1 will flow into the mixing box 2. Since the second connecting pipe 9 can input air into the mixing box 2, the liquid nitrogen will generate cooling gas after mixing with the air in the mixing box 2, that is, forming a cooling medium for cooling the closed water. The generated cooling gas will enter the second heat exchange pipeline 4 and flow along the extension direction of the second heat exchange pipeline 4. At the same time, the first heat exchange pipeline 3 will also be opened to allow the closed water in the closed water pipeline 12 to flow in. Because at least part of the second heat exchange pipeline 4 is located in the first heat exchange pipeline 3, the cooling gas can cool the closed water located in the first heat exchange pipeline 3 during the flow of the second heat exchange pipeline 4, thereby ensuring that the closed water can cool the equipment in the thermal power plant, so that the thermal power plant can maintain a normal operating state.

[0025] The liquid storage box 1 can be configured as a steel box body to store liquid nitrogen. Of course, it can also be a liquid storage tank or a liquid storage bottle.

[0026] In some embodiments of the present disclosure, the second heat exchange pipeline 4 includes a delivery pipeline 401, an inlet header 402, an outlet header 403, and a plurality of shunt pipes 404 arranged in parallel and at least partially located in the first heat exchange pipeline 3. The delivery pipeline 401 is respectively connected to the inlet header 402 and one end of the mixing box 2, and the two ends of the shunt pipe 404 are respectively connected to the other ends of the inlet header 402 and the outlet header 403. After flowing out of the mixing box 2, the cooling gas enters the delivery pipeline 401 and is collected in the inlet header 402. The collected cooling gas is divided into multiple paths and enters the first heat exchange pipeline 3 under the action of the shunt pipe 404, so that the cooling gas can increase the heat exchange area with the closed water in the first heat exchange pipeline 3 through the shunt pipe 404, so as to improve the heat exchange efficiency and ensure the cooling effect of the cooling gas on the closed water. The cooling gas after heat exchange is collected in the outlet header 403 and discharged from the outlet header 403.

[0027] Since condensed water is also generated when liquid nitrogen is mixed with air to generate cooling gas, a drain pipe 5 is provided at the bottom of the mixing box 2 and / or the outlet header 403 to discharge the generated condensed water.

[0028] In some embodiments, the delivery pipeline 401 is provided with an induced draft fan 6 for guiding the cooling medium to move along the second heat exchange pipeline 4. The induced draft fan 6 can drive the generated cooling gas to flow stably in the second heat exchange pipeline 4, so that new cooling gas continuously flows through the shunt pipe 404 located in the first heat exchange pipeline 3, thereby ensuring the cooling effect of the closed water in the first heat exchange pipeline 3.

[0029] In some embodiments of the present disclosure, a temperature measuring element 7 is provided on the delivery pipeline 401 and the outlet header 403. Of course, a temperature measuring element 7 can also be provided on the closed water pipeline 12, and the temperature measuring element 7 can transmit the detected temperature signal to the DCS system. The DCS system can adjust the flow rate of the cooling gas entering the second heat exchange pipeline 4 or adjust the temperature of the cooling gas according to the temperature signal. For example, when the closed water temperature in the first heat exchange pipeline 3 is high, the DCS system can increase the flow rate of liquid nitrogen and air entering the mixing box 2, thereby increasing the cooling gas generated and increasing the flow rate of the cooling gas to ensure the cooling effect of the closed water. Alternatively, the DCS system can also only increase the flow rate of liquid nitrogen entering the mixing box 2 to reduce the temperature of the cooling gas and improve the cooling efficiency of the cooling gas. On the contrary, when the temperature in the first heat exchange pipeline 3 is low, the DCS system can also reduce the flow rate of liquid nitrogen and air entering the mixing box 2, or only reduce the flow rate of liquid nitrogen entering the mixing box 2. In addition, the DCS system's detection of the temperatures of the delivery pipeline 401 and the outlet header 403 can also prevent the occurrence of pipeline rupture in the heat exchange system due to the excessively low temperature of the cooling gas, thereby ensuring the overall operational stability of the heat exchange system.

[0030] Specifically, an electric regulating valve 10 for regulating the flow of the medium is provided on the first connecting pipe 8 and / or the second connecting pipe 9. The opening size of the electric regulating valve 10 is controlled by the DCS system, thereby regulating the flow of the medium.

[0031] In some embodiments, there may be multiple liquid storage tanks 1, and the multiple liquid storage tanks 1 are arranged in parallel and can be connected to the mixing box 2 through the first connecting pipe 8. Each liquid storage tank 1 is equipped with a switch valve. When in use, the staff can choose to open one liquid storage tank 1 or multiple liquid storage tanks 1 according to the current situation. For example, when it is necessary to increase the flow rate of liquid nitrogen to reduce the temperature of the cooling gas, multiple switch valves can be opened at the same time. On the contrary, when more cooling gas is not needed, the switch valve of one of the liquid storage tanks 1 can be opened. In addition, multiple liquid storage tanks 1 can also be used as backup for each other to ensure the normal operation of the heat exchange system.

[0032] In addition, the heat exchange system of the present invention may also include a compressed air pipeline 11 that can be connected to the mixing box 2 in a switchable manner. Since the humidity of the air is sometimes relatively high, it will generate excessive condensate when it is mixed with liquid nitrogen to generate cooling gas. This condensate may freeze the drain pipe in winter, thereby affecting the normal operation of the heat exchange system. Compressed air is relatively dry, and when the air humidity is high, compressed air can be used instead of air with higher humidity.

[0033] The second aspect of the present disclosure provides a thermal power plant system, including an open water system, a closed water pipeline 12 and the above-mentioned heat exchange system, wherein the open water system is arranged in parallel with the closed water pipeline 12 and is connected to the closed water pipeline 12 through another first heat exchange pipeline 3 in the open water system; or, the open water system includes an open water pipeline (not shown in the figure), which is connected to the second heat exchange pipeline 4 in an on-off manner. Under normal circumstances, the closed water system is cooled by the open water system, that is, the cooling water cools the closed water in the first heat exchange pipeline 3 while passing through the second heat exchange pipeline 4. When the closed water system has a problem and cannot work, the heat exchange system of the present disclosure is started. In addition, the thermal power plant system has all the beneficial effects of the heat exchange system, which will not be repeated in this disclosure.

[0034] The closed water pipeline 12 is connected to the first heat exchange pipeline 3 through the third connecting pipe 13 in an on-off manner, and two third connecting pipes 13 are provided, and the two third connecting pipes 13 are arranged at intervals along the extension direction of the closed water pipeline 12. In this way, the closed water in the first heat exchange pipeline 3 can be in a flowing state, thereby ensuring the cooling effect of the cooling gas on the closed water.

[0035] In summary, the present disclosure exemplarily illustrates the use process of the heat exchange system of the present disclosure.

[0036] The closed water in the closed water pipeline 12 is generally cooled by the open water system. When the open water system has a problem and cannot be cooled, the heat exchange system of the present disclosure is turned on, and the third connecting pipe 13 is opened, so that the closed water in the closed water pipeline 12 enters the first heat exchange pipeline 3. At the same time, the electric regulating valve 10 of the first connecting pipe 8 and the second connecting pipe 9 is opened, so that the liquid nitrogen in the liquid storage tank 1 can enter the mixing box 2 through the first connecting pipe 8, and the outside air can enter the mixing box 2 through the second connecting pipe 9. After mixing in the mixing box 2, cooling gas will be generated. Under the action of the induced draft fan 6, the cooling gas will be collected at the inlet header 402 through the delivery pipeline 401, and then enter the branch pipe 404 to exchange heat with the closed water in the first heat exchange pipeline 3 to reduce the temperature of the closed water in the closed water pipeline 12, thereby ensuring that the closed water can cool the equipment in the thermal power plant, so that the thermal power plant can maintain normal operation. Finally, the cooling gas that has completed the heat exchange will be collected in the outlet header 403 and discharged through the pipeline.

[0037] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0038] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0039] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A heat exchange system for a closed water pipeline, characterized in that: include: A liquid storage tank for storing liquid nitrogen; A mixing box, connected to the liquid storage tank, used for mixing the liquid nitrogen with air to form a cooling medium; A second connecting pipe is connected to the mixing box in an on-off manner and is used to input air into the mixing box; A first heat exchange pipeline, used to be connected in parallel with the closed water pipeline in a switchable manner; as well as The second heat exchange pipeline is connected to the mixing box and is used to transport the cooling medium. At least a part of the second heat exchange pipeline is located in the first heat exchange pipeline.

2. The heat exchange system according to claim 1, characterized in that: The second heat exchange pipeline includes a delivery pipeline, an inlet header, an outlet header and a plurality of branch pipes which are arranged in parallel with each other and at least partially located in the first heat exchange pipeline. The delivery pipeline is respectively connected to one end of the inlet header and the mixing box, and both ends of the branch pipe are respectively connected to the other end of the inlet header and the outlet header.

3. The heat exchange system according to claim 2, characterized in that: A drain pipeline is provided at the bottom of the mixing box and / or the outlet header.

4. The heat exchange system according to claim 2, characterized in that: The conveying pipeline is provided with an induced draft fan for guiding the cooling medium to move along the second heat exchange pipeline.

5. The heat exchange system according to claim 2, characterized in that: The conveying pipeline and the outlet header are provided with temperature measuring elements.

6. The heat exchange system according to claim 1, characterized in that: There are multiple liquid storage tanks, and the multiple liquid storage tanks are arranged in parallel and are connected to the mixing box body in an on-off manner through a first connecting pipe.

7. The heat exchange system according to claim 6, characterized in that: The first connecting pipe and / or the second connecting pipe is provided with an electric regulating valve for regulating the flow of the medium.

8. The heat exchange system according to any one of claims 1 to 7, characterized in that: The heat exchange system also includes a compressed air pipeline which is connected to the mixing box in an on-off manner.

9. A thermal power plant system, characterized in that: A heat exchange system comprising an open water system, a closed water pipeline and any one of claims 1 to 8, wherein the open water system is arranged in parallel with the closed water pipeline and is connected to the closed water pipeline in an on-off manner through another first heat exchange pipeline in the open water system; or, the open water system comprises an open water pipeline, and the open water pipeline is connected to the second heat exchange pipeline in an on-off manner.

10. The thermal power plant system according to claim 9, characterized in that: The closed water pipeline is connected to the first heat exchange pipeline in an on-off manner through a third connecting pipe. Two third connecting pipes are provided, and the two third connecting pipes are arranged at intervals along the extension direction of the closed water pipeline.

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