Shell and tube type steam seal cooler and cooling method

Abstract

The invention provides a shell and tube type steam seal cooler and a cooling method.The shell and tube type steam seal cooler comprises a cooling cylinder, a baffle is arranged in the cooling cylinder and divides the interior of the cooling cylinder into a left cooling cavity and a right cooling cavity, and the left cooling cavity and the right cooling cavity are communicated; the left cooling cavity is provided with a steam seal steam leakage inlet and a steam exhaust port, the right cooling cavity is provided with a valve rod steam leakage inlet, and the bottom of the cooling cylinder is further provided with a drainage port. A cooling water inlet is formed in the left cooling cavity, a cooling water outlet is formed in the right cooling cavity, a cooling tube bundle is arranged in the cooling cylinder and extends to the right cooling cavity from the left cooling cavity, the cooling water inlet is communicated with a left port of the cooling tube bundle, and the cooling water outlet is communicated with a right port of the cooling tube bundle. The problems that in the prior art, a steam seal cooler is low in heat exchange efficiency and large in size are solved.

Description

Technical Field

[0001] This invention relates to the field of steam turbine equipment technology, and in particular to a shell-and-tube steam seal cooler and cooling method. Background Technology

[0002] There are two types of existing steam turbine seal coolers. One type consists of a cooling cylinder and two steam seal cooling fans. When the steam turbine is running, due to the different sealing methods and operating pressures of the shaft seal and valve stem, steam leakage with lower pressure and temperature and containing non-condensable gas (air) that affects heat exchange efficiency will be generated, and steam leakage with higher temperature and pressure and not containing non-condensable gas (air) that affects heat exchange efficiency will be generated. The two types of steam leakage mix in the pipeline and enter the cooling cylinder of the steam turbine seal cooler, where they are cooled and condensed by the cooling water in the cooling pipes. The condensed water enters the condenser through the drain port at the bottom of the cooling cylinder. Uncondensed steam from the steam seal and valve stem, as well as non-condensable gas (air), are discharged from the fan port of the steam seal cooler. As in the technology of patent CN110118110A, due to the small heat exchange end difference and the presence of non-condensable gas (air), the condensation effect of the steam seal cooler on steam seal and valve stem leakage becomes poor, resulting in a large amount of uncondensed steam being extracted by the steam seal cooler fan, causing a waste of working fluid and heat.

[0003] Another type is a cooling cylinder structure, as described in patent CN204513350U, which has multiple steam inlet ports on the cooling cylinder so that the cooling water first cools the low-temperature steam, then the medium-temperature steam, and finally the high-temperature steam. However, because the non-condensable gas that affects the heat exchange efficiency is evenly distributed throughout the cooling cylinder, it affects the heat exchange efficiency of the cooler. As a result, a large amount of steam leakage from the steam seal and valve rod does not condense into water but is discharged through the exhaust port, causing a waste of working fluid and heat.

[0004] Another design uses two cooling cylinders and two steam seal cooling fans, as disclosed in patent CN114109531A. One cooling cylinder cools valve stem leaks that have higher pressure and temperature and do not contain non-condensable gases (air) that affect heat exchange efficiency. The other cooling cylinder cools steam seal leaks that have lower pressure and temperature and contain non-condensable gases (air) that affect heat exchange efficiency. The condensate formed during cooling is drained to the condenser through a drain port at the bottom of the cylinder. Because this design consists of two cooling cylinders, the steam seal cooler is relatively large, occupies a large area, and has low air utilization. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a shell-and-tube steam seal cooler and a cooling method. This shell-and-tube steam seal cooler can improve heat exchange efficiency while being small in size and occupying a small area, thereby solving the problems of low heat exchange efficiency and large size of existing steam seal coolers.

[0006] To achieve the above and other related objectives, one aspect of the present invention provides a shell-and-tube steam seal cooler, comprising a cooling cylinder, wherein a baffle is provided inside the cooling cylinder to divide the cooling cylinder into a left cooling chamber and a right cooling chamber, and the left cooling chamber and the right cooling chamber are connected; wherein the left cooling chamber is provided with a steam seal leakage inlet and a steam outlet, the right cooling chamber is provided with a valve stem leakage inlet, and a drain outlet is provided at the bottom of the cooling cylinder; a cooling water inlet is provided on the left cooling chamber, and a cooling water outlet is provided on the right cooling chamber; a cooling tube bundle is provided inside the cooling cylinder, the cooling tube bundle extending from the left cooling chamber to the right cooling chamber, the cooling water inlet being connected to the left port of the cooling tube bundle, and the cooling water outlet being connected to the right port of the cooling tube bundle.

[0007] Preferably, it also includes an exhaust fan, which is connected to the exhaust port.

[0008] Preferably, there are two exhaust fans, and both exhaust fans are connected to the exhaust port.

[0009] Preferably, the baffle is disposed in the middle of the cooling cylinder.

[0010] Another aspect of the present invention provides a cooling method using the shell-and-tube steam seal cooler described above, the cooling method comprising the following steps:

[0011] Steam leakage from the steam seal enters the left cooling chamber through the steam seal leakage inlet, and steam leakage from the valve stem enters the right cooling chamber through the valve stem leakage inlet.

[0012] Cooling water flows from the left cooling chamber to the right cooling chamber through the cooling tube bundle. The cooling water first cools the steam seal leakage in the left cooling chamber, and then cools the valve stem leakage in the right cooling chamber. The water condensed from the steam seal leakage and valve stem leakage flows out from the drain port.

[0013] Some uncondensed steam seal leakage, valve stem leakage, and non-condensable gas are discharged from the exhaust port.

[0014] As described above, the shell-and-tube steam seal cooler and cooling method of the present invention have the following beneficial effects: Based on the shell-and-tube steam seal cooler and cooling method, the shell-and-tube steam seal cooler can avoid cooling the valve stem leakage steam with a higher temperature first, which would cause the temperature of the cooling water to rise, and thus affect the condensation of the steam seal leakage steam when heat exchange and condensation is performed. Furthermore, the shell-and-tube steam seal cooler divides a cooling cylinder into two cooling chambers, so that the valve stem leakage steam will not mix with the steam seal leakage steam containing non-condensable gas (air) that affects the heat exchange efficiency. This allows the pure valve stem leakage steam to achieve pure steam condensation in the right cooling chamber, thereby significantly improving the condensation efficiency of the valve stem leakage steam. At the same time, the shell-and-tube steam seal cooler of the present invention is also smaller in size, occupies less space, and has a high space utilization rate. Attached Figure Description

[0015] Figure 1 The diagram shows the internal medium flow of the shell-and-tube steam seal cooler provided by the present invention.

[0016] Figure 2 The diagram shown is a structural schematic of the shell-and-tube steam seal cooler provided by the present invention.

[0017] Explanation of reference numerals in the attached figures

[0018] 10 Cooling cylinder

[0019] 101 Left cooling chamber

[0020] 102 Right cooling chamber

[0021] 11 baffles

[0022] 12. Steam seal leakage at the steam inlet.

[0023] 13 Exhaust ports

[0024] 131 Exhaust fan

[0025] 1311 First Exhaust Fan

[0026] 1312 Second Exhaust Fan

[0027] 14. Steam leakage at the valve stem inlet.

[0028] 15 Drainage outlets

[0029] 16 Cooling water inlet

[0030] 17 Cooling water outlet Detailed Implementation

[0031] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0032] The terms "first" and "second," etc., used in the specification and drawings of this application are used to distinguish different objects or to distinguish different treatments of the same object, rather than to describe a specific order of objects.

[0033] Furthermore, the terms "comprising" and "having," and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0034] Before discussing the exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but may also have additional steps not included in the figures. The process can correspond to a method, function, procedure, subroutine, subroutine, etc. Moreover, embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0035] Please see Figure 1 and Figure 2 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0036] One aspect of the present invention provides a shell-and-tube steam seal cooler, such as Figure 1 and Figure 2As shown, the shell-and-tube steam seal cooler includes a cooling cylinder 10. A baffle 11 is provided inside the cooling cylinder 10, dividing the interior of the cooling cylinder 10 into a left cooling chamber 101 and a right cooling chamber 102. The left and right cooling chambers 101 and 102 are connected; that is, the baffle 11 does not completely isolate the left and right cooling chambers 101 and 102. Specifically, the left cooling chamber 101 has a steam seal leakage inlet 12 and an outlet 13, and the right cooling chamber 102 has a valve. The cooling cylinder 10 has a steam inlet 14 and a drain outlet 15 at the bottom. Specifically, the left cooling chamber 101 has a cooling water inlet 16 and the right cooling chamber 102 has a cooling water outlet 17. The cooling cylinder 10 also has a cooling tube bundle (not shown in the figure) inside. The cooling tube bundle extends from the left cooling chamber 101 to the right cooling chamber 102. The cooling water inlet 16 is connected to the left end of the cooling tube bundle and the cooling water outlet 17 is connected to the right end of the cooling tube bundle.

[0037] In use, the shell-and-tube steam seal cooler of the present invention allows steam seal leakage with lower pressure and temperature and containing air to enter the left cooling chamber 101 through the steam seal leakage inlet 12, while valve stem leakage with higher temperature and pressure and not containing non-condensable gas (air) enters the right cooling chamber 102 through the valve stem leakage inlet 14. Cooling water flows from the left cooling chamber 101 to the right cooling chamber 102 through the cooling tube bundle. That is, the cooling water first condenses the lower-temperature steam seal leakage in the left cooling chamber 101, and when the cooling water in the cooling tube bundle flows to the right cooling chamber 102, it then condenses the higher-temperature valve stem leakage in the right cooling chamber. The condensate in both the left and right cooling chambers flows out through the drain outlet 15 at the bottom of the cooling cylinder 10. Some of the uncondensed steam seal leakage, valve stem leakage, and non-condensable gas are discharged through the exhaust outlet 13. This design avoids the problem of cooling the valve stem leakage at a higher temperature first, which would raise the temperature of the cooling water and cause low heat exchange efficiency when condensing the steam seal leakage. Furthermore, this invention divides a cooling cylinder 10 into two cooling chambers, preventing the valve stem leakage from mixing with the steam seal leakage containing non-condensable gases (air) that affect heat exchange efficiency. This allows the pure valve stem leakage to condense into pure steam in the right cooling chamber 102, significantly improving the condensation efficiency of the valve stem leakage. In addition, the shell-and-tube steam seal cooler of this invention has a single cooling cylinder structure, resulting in a smaller volume, less floor space, and higher space utilization.

[0038] Specifically, such as Figure 1As shown, in this embodiment, the baffle 11 is disposed in the middle of the cooling cylinder 10, that is, the baffle 11 divides the interior of the cooling cylinder 10 into a left cooling chamber 101 and a right cooling chamber 102.

[0039] Specifically, during operation, when the turbine reaches full load, the valve stem achieves self-sealing with no valve stem leakage, or for operating conditions with very little valve stem leakage, the valve stem leakage chamber may experience a short-term slight negative pressure state. If both the dynamic and static seals at the valve stem end are not properly sealed, a small amount of air mixed in with the valve stem leakage will also enter the right cooling chamber, then pass through the left cooling chamber, and finally be discharged from the exhaust port on the left cooling chamber.

[0040] Furthermore, to improve the smoothness of uncondensed steam seal leakage, valve stem leakage, and non-condensable gas (air) discharge from exhaust port 13, preferably, such as Figure 2 As shown, in this embodiment, the shell-and-tube steam seal cooler also includes an exhaust fan 131 connected to the exhaust port 13, so that the uncondensed steam seal leakage, valve stem leakage and non-condensable gas can be extracted from the exhaust port 13 from the inside of the cooling cylinder 10 through the exhaust fan 131.

[0041] Preferably, in order to further improve the efficiency and smoothness of the discharge of uncondensed steam seal leakage, valve stem leakage and non-condensable gas from the exhaust port 13, in this embodiment, two exhaust fans 131 are provided, namely a first exhaust fan 1311 and a second exhaust fan 1312, both of which are connected to the exhaust port 13.

[0042] Furthermore, it should be noted that in this application, the cooling cylinder 10 is not limited to the horizontal type in the above embodiments. In other optional embodiments, the cooling cylinder 10 may also adopt a vertical structure.

[0043] Another aspect of the present invention provides a cooling method using the shell-and-tube steam seal cooler described above, the cooling method comprising the following steps:

[0044] S1. Steam leakage from the steam seal enters the left cooling chamber through the steam seal leakage inlet, and steam leakage from the valve stem enters the right cooling chamber through the valve stem leakage inlet.

[0045] S2. Cooling water flows from the left cooling chamber to the right cooling chamber through the cooling tube bundle. The cooling water first cools the steam seal leakage in the left cooling chamber, and then cools the valve stem leakage in the right cooling chamber. The water condensed from the steam seal leakage and valve stem leakage flows out from the drain port.

[0046] S3. Some uncondensed steam seals leak steam, valve stems leak steam, and non-condensable gases are discharged from the exhaust port.

[0047] Specifically, in step S3, in order to improve the smoothness of the discharge of uncondensed steam seal leakage, valve stem leakage and non-condensable gas (air) from the exhaust port 13, in this embodiment, the shell-and-tube steam seal cooler also includes an exhaust fan 131 connected to the exhaust port 13, so that the uncondensed steam seal leakage, valve stem leakage and non-condensable gas can be extracted from the inside of the cooling cylinder 10 through the exhaust port 13 by the exhaust fan 131.

[0048] In summary, the shell-and-tube steam seal cooler and cooling method of the present invention have the advantage of requiring a lower shell-side design temperature. Furthermore, while improving heat exchange efficiency, the shell-and-tube steam seal cooler of the present invention is also smaller in size, occupies less floor space, and has high space utilization. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0049] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A shell-and-tube steam seal cooler, characterized in that, include: A cooling cylinder (10) is provided inside, and a baffle (11) is provided inside the cooling cylinder (10) to divide the interior of the cooling cylinder (10) into a left cooling chamber (101) and a right cooling chamber (102), and the left cooling chamber (101) and the right cooling chamber (102) are connected; wherein, the left cooling chamber (101) is provided with a steam seal leakage steam inlet (12) and a steam outlet (13), the right cooling chamber (102) is provided with a valve stem leakage steam inlet (14), and a drain outlet (15) is also provided at the bottom of the cooling cylinder (10); The left cooling chamber (101) is provided with a cooling water inlet (16), the right cooling chamber (102) is provided with a cooling water outlet (17), the cooling cylinder (10) is provided with a cooling tube bundle inside, the cooling tube bundle extends from the left cooling chamber (101) to the right cooling chamber (102), the cooling water inlet (16) is connected to the left port of the cooling tube bundle, and the cooling water outlet (17) is connected to the right port of the cooling tube bundle.

2. A shell-and-tube steam seal cooler according to claim 1, characterized in that, It also includes an exhaust fan (131) connected to the exhaust port (13).

3. A shell-and-tube steam seal cooler according to claim 2, characterized in that, There are two exhaust fans (131), and both exhaust fans (131) are connected to the exhaust port (13).

4. A shell-and-tube steam seal cooler according to claim 1, characterized in that, The baffle (11) is located in the middle of the cooling cylinder (10).

5. A cooling method using a shell-and-tube steam seal cooler as described in any one of claims 1 to 4, characterized in that, The cooling method includes the following steps: Steam leakage from the steam seal enters the left cooling chamber (101) through the steam seal leakage inlet (12), and steam leakage from the valve stem enters the right cooling chamber (102) through the valve stem leakage inlet (14). Cooling water flows from the left cooling chamber (101) to the right cooling chamber (102) through the cooling tube bundle. The cooling water first cools the steam seal leakage in the left cooling chamber (101) and then cools the valve stem leakage in the right cooling chamber (102). The water condensed from the steam seal leakage and valve stem leakage flows out from the drain port (15). Some uncondensed steam seal leakage, valve stem leakage, and non-condensable gas are discharged from the exhaust port.

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