A device integrating steam injection, exhaust and steam seal cooling functions

Abstract

The present invention discloses a device integrating steam jetting, exhaust and steam seal cooling functions, including a working steam generating pipe, a steam-gas mixture exhaust pipe, a starting ejector, a first-stage ejector, a second-stage ejector, a steam seal ejector, an exhaust first-stage shell-and-tube heat exchanger, a second-stage shell-and-tube heat exchanger and a steam seal first-stage shell-and-tube heat exchanger; the exhaust first-stage shell-and-tube heat exchanger is connected with the second-stage shell-and-tube heat exchanger through an inlet and outlet water chamber, and the second-stage shell-and-tube heat exchanger is connected with the steam seal first-stage shell-and-tube heat exchanger through a transition water chamber; the exhaust first-stage shell-and-tube heat exchanger, the second-stage shell-and-tube heat exchanger and the steam seal first-stage shell-and-tube heat exchanger are coaxially arranged, and the second-stage shell-and-tube heat exchanger is located between the exhaust first-stage shell-and-tube heat exchanger and the steam seal first-stage shell-and-tube heat exchanger. The device integrating steam jetting, exhaust and steam seal cooling functions of the present invention reduces the occupied plant area, reduces the arrangement of steam pipes and the arrangement of heat exchangers, and makes the operation more convenient.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbine exhaust machinery, and in particular to a device integrating steam injection exhaust and steam seal cooling functions. Background Art

[0002] The task of the vacuum pump is to continuously extract the air that leaks into the condenser side space through the steam turbine condenser under negative pressure and the loose parts of the pipeline, so as to maintain the vacuum of the condenser and good heat transfer. The vacuum pump includes a single-stage starting vacuum pump and a two-stage main vacuum pump. The starting vacuum pump is used to quickly establish a vacuum sufficient for the condenser to start the steam turbine before the steam turbine is started. The main vacuum pump works with the operation of the condenser when the steam turbine is working normally. The starting vacuum pump is a single-stage steam ejector vacuum pump without a heat exchanger. When working, it directly discharges all steam-air mixture into the atmosphere. The main vacuum pump consists of two single-stage steam ejectors and two corresponding heat exchangers connected in series. The vacuum pump is an independent device and is arranged separately in the plant.

[0003] The function of the steam seal cooler is to make the leakage pipes of the steam seals before and after the steam turbine slightly negative pressure, so that the leakage can continuously enter the steam seal cooler through the leakage pipe, and condense it into water for reuse by the boiler. The working mode of the steam seal cooler is roughly as follows: the shaft seal steam from the front and rear of the steam turbine passes through the leakage pipe and enters the heat exchanger of the steam seal cooler from the leakage inlet of the steam seal cooler, and condenses into water and is discharged from the drain port. Since there is some non-condensable air in the leakage, in order to make the leakage continuously pass through the leakage pipe and enter the steam seal cooler, the gas needs to be extracted, which requires the air and residual steam to be discharged into the atmosphere through a steam ejector. The steam seal cooler is also an independent equipment, which is arranged separately in the factory.

[0004] It can be seen that the vacuum pump and steam seal cooler are two separate devices, which require separate steam pipes and heat exchangers when used. This will take up too much plant area, and multiple separate devices are not convenient to operate. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a device integrating steam injection, exhaust and steam seal cooling functions, which reduces the occupied plant area, reduces the layout of steam pipes and heat exchangers, and makes operation more convenient.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] A device integrating steam injection, air extraction and steam seal cooling functions, comprising a working steam generating pipe, a steam-gas mixture extraction pipe, a starting ejector, a first-stage ejector, a second-stage ejector, a steam seal ejector and a shell-and-tube heat exchanger; the starting ejector comprises a starting nozzle, a starting mixing chamber and a starting pressure diffuser; the first-stage ejector comprises a first-stage nozzle, a first-stage mixing chamber and a first-stage pressure diffuser; the second-stage ejector comprises a second-stage nozzle, a second-stage mixing chamber and a second-stage pressure diffuser; the steam seal ejector comprises a steam seal nozzle, a steam seal mixing chamber and a steam seal pressure diffuser; the shell-and-tube heat exchanger comprises an air extraction first-stage shell-and-tube heat exchanger The first-stage exhaust shell and tube heat exchanger is connected to the second-stage shell and tube heat exchanger through an inlet and outlet water chamber, and the second-stage shell and tube heat exchanger is connected to the first-stage steam-sealed shell and tube heat exchanger through a transition water chamber; the first-stage exhaust shell and tube heat exchanger, the second-stage shell and tube heat exchanger and the first-stage steam-sealed shell and tube heat exchanger are coaxially arranged, and the second-stage shell and tube heat exchanger is located between the first-stage exhaust shell and tube heat exchanger and the first-stage steam-sealed shell and tube heat exchanger, and the ends of the first-stage exhaust shell and tube heat exchanger and the first-stage steam-sealed shell and tube heat exchanger are both provided with a reflux water chamber;

[0008] The starting nozzle, the first-level nozzle, the second-level nozzle and the steam seal nozzle are connected to the working steam generating pipe through the steam pipes arranged in parallel; the first-level mixing chamber is connected to the steam-gas mixture suction pipe; the gradually expanding section of the starting diffuser pipe is connected to the vent pipe; the gradually expanding section of the first-level diffuser pipe is connected to the first-level exhaust shell and tube heat exchanger, the second-level mixing chamber is connected to the first-level exhaust shell and tube heat exchanger, and the gradually expanding section of the second-level diffuser pipe is connected to the second-level shell and tube heat exchanger; the steam seal mixing chamber is connected to the first-level steam seal shell and tube heat exchanger, and the gradually expanding section of the steam seal diffuser pipe is connected to the second-level shell and tube heat exchanger;

[0009] The first-stage exhaust shell and tube heat exchanger is provided with a first-stage exhaust drain port; the second-stage shell and tube heat exchanger is provided with a second-stage exhaust port and a second-stage drain port; the first-stage steam seal shell and tube heat exchanger is provided with a steam seal leakage port and a first-stage steam seal drain port.

[0010] Furthermore, a water chamber drain port is provided at the bottom of the reflux water chamber, and a water chamber air vent is provided at the top of the reflux water chamber.

[0011] Furthermore, the number of the first-stage injectors and the second-stage injectors is two.

[0012] Furthermore, the bottoms of the exhaust first-stage shell and tube heat exchanger, the second-stage shell and tube heat exchanger and the steam-sealed first-stage shell and tube heat exchanger are all provided with brackets.

[0013] Furthermore, the water inlet of the inlet and outlet water chamber is located at the bottom, and the water outlet of the water inlet water chamber is located at the top.

[0014] Furthermore, a muffler is connected between the gradually expanding section of the starting diffuser pipe and the vent pipe.

[0015] Furthermore, a safety valve is also provided on the exhaust first-stage shell and tube heat exchanger.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the first-stage ejector, the second-stage ejector, the first-stage exhaust shell and tube heat exchanger and the second-stage shell and tube heat exchanger actually constitute a two-stage steam ejector exhauster, realizing the function of steam ejection exhaust; and the steam seal ejector, the first-stage steam seal shell and tube heat exchanger and the second-stage shell and tube heat exchanger actually constitute a steam seal cooler, realizing the function of steam seal cooling; that is, the present invention integrates the functions of steam ejection exhaust and steam seal cooling, and when integrating the above functions, shares the second-stage shell and tube heat exchanger and the working steam generating tube, and because the first-stage exhaust shell and tube heat exchanger, the second-stage shell and tube heat exchanger and the first-stage steam seal shell and tube heat exchanger are coaxially arranged, the ends of the first-stage exhaust shell and tube heat exchanger and the first-stage steam seal shell and tube heat exchanger are provided with a reflux water chamber, so that the three shell and tube heat exchangers can share one circulating water, and the above-mentioned arrangement makes the equipment highly integrated, reduces the occupied plant area, reduces the layout of steam pipes, reduces the layout of circulating water pipes, makes the plant area tidier and the operation more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The schematic diagram of the structure of the ejector is shown in FIG.

[0018] Figure 2 A three-dimensional diagram of a device integrating steam injection, exhaust and steam seal cooling functions according to the present invention;

[0019] Figure 3 It is a front view of the device integrating steam injection, exhaust and steam seal cooling functions of the present invention;

[0020] Figure 4 It is a left view of the device integrating steam injection, exhaust and steam seal cooling functions of the present invention;

[0021] Figure 5 A top view of the device of the present invention integrating steam injection, air extraction and steam seal cooling functions;

[0022] Figure 6 Schematic diagram of the flow of cooling water in a tube bundle heat exchanger.

[0023] In the figure: 11, nozzle; 12, mixing chamber; 13, diffuser; 131, contraction section; 132, gradual expansion section; 21, working steam generating pipe; 22, steam-gas mixture suction pipe; 23, starting mixing chamber; 24, primary mixing chamber; 25, secondary mixing chamber; 26, steam seal mixing chamber; 31, exhaust first-stage shell and tube heat exchanger; 311, exhaust first-stage drain port; 32, secondary shell and tube heat exchanger; 321, secondary exhaust port; 322, secondary drain port; 33, steam seal first-stage shell and tube heat exchanger; 331, steam seal air leakage port; 332, steam seal first-stage drain port; 41, inlet and outlet water chamber; 411, water inlet; 412, water outlet; 42, transition water chamber; 43, reflux water chamber; 431, drain port; 432, air vent; 5, bracket; 6, vent pipe; 7, silencer; 8, safety valve. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are provided in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0025] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0027] It should be noted that the ejector belongs to the prior art and is composed of three parts: a nozzle 11, a mixing chamber 12 and a diffuser 13. Figure 1As shown. Its working principle is as follows: after the working steam enters the nozzle 11, it is depressurized and expanded, forming a high-speed airflow at the outlet section 1-1, entering the mixing chamber 12, and ejecting the low-speed steam-air mixture from the condenser, entering the inlet section 2-2 of the diffuser 13, passing through the contraction section 131 of the diffuser 13, the throat and the gradually expanding section 132 are adiabatically compressed to a certain pressure, and then enter the heat exchanger to condense the steam. In the present invention, the starting ejector, the first-stage ejector, the second-stage ejector and the steam seal ejector have the same principle as above.

[0028] like Figure 2-5 As shown, a device with integrated steam injection, exhaust and steam seal cooling functions provided by an embodiment of the present invention is shown, which includes a working steam generating pipe 21, a steam-gas mixture exhaust pipe 22, a starting ejector, a first-stage ejector, a second-stage ejector, a steam seal ejector and a shell-and-tube heat exchanger. The starting ejector includes a starting nozzle, a starting mixing chamber 23 and a starting diffuser pipe ( Figure 2 Only the starting mixing chamber 23 is shown); the first-stage ejector includes a first-stage nozzle, a first-stage mixing chamber 24 and a first-stage diffuser ( Figure 2 Only the primary mixing chamber 24 is shown); the secondary ejector includes a secondary nozzle, a secondary mixing chamber 25 and a secondary diffuser ( Figure 2 Only the secondary mixing chamber 25 is shown in FIG. 1 ); the steam seal injector includes a steam seal nozzle, a steam seal mixing chamber 26 and a steam seal diffuser ( Figure 2 Only the steam seal mixing chamber 26 is shown).

[0029] The shell and tube heat exchanger includes an exhaust first-stage shell and tube heat exchanger 31, a second-stage shell and tube heat exchanger 32, and a steam-sealed first-stage shell and tube heat exchanger 33; the bottoms of the exhaust first-stage shell and tube heat exchanger 31, the second-stage shell and tube heat exchanger 32, and the steam-sealed first-stage shell and tube heat exchanger 33 are all provided with a bracket 5. Specifically, the exhaust first-stage shell and tube heat exchanger 31, the second-stage shell and tube heat exchanger 32, and the steam-sealed first-stage shell and tube heat exchanger 33 all adopt a floating head tube plate structure, and in the present invention, the three shell and tube heat exchangers all adopt a two-tube pass structure. The exhaust first-stage shell and tube heat exchanger 31 and the second-stage shell and tube heat exchanger 32 are connected through an inlet and outlet water chamber 41, the water inlet 411 of the inlet and outlet water chamber 41 is located at the bottom, and the water outlet 412 of the inlet and outlet water chamber 41 is located at the top. The secondary shell and tube heat exchanger 32 is connected to the steam-sealed primary shell and tube heat exchanger 33 through a transition water chamber 42; the primary exhaust shell and tube heat exchanger 31, the secondary shell and tube heat exchanger 32 and the primary steam-sealed shell and tube heat exchanger 33 are coaxially arranged, and the secondary shell and tube heat exchanger 32 is located between the primary exhaust shell and tube heat exchanger 31 and the steam-sealed primary shell and tube heat exchanger 33, and the ends of the primary exhaust shell and tube heat exchanger 31 and the steam-sealed primary shell and tube heat exchanger 33 are both provided with a reflux water chamber 43. Specifically, a water chamber drain port 431 is provided at the bottom of the reflux water chamber 43, and a water chamber vent port 432 is provided at the top of the reflux water chamber 43. Figure 6 The figure shows the flow direction of cooling water in a tube bundle heat exchanger (the arrows in the figure represent the flow direction of cooling water).

[0030] The starting nozzle, the first-level nozzle, the second-level nozzle and the steam-sealing nozzle are connected to the working steam generating pipe 21 through steam pipes arranged in parallel; the first-level mixing chamber 24 is connected to the steam-gas mixture suction pipe 22; the gradually expanding section of the starting diffuser pipe is connected to the vent pipe 6; the gradually expanding section of the first-level diffuser pipe is connected to the first-level shell and tube heat exchanger 31 for exhaust, the second-level mixing chamber 25 is connected to the first-level shell and tube heat exchanger 31 for exhaust, and the gradually expanding section of the second-level diffuser pipe is connected to the second-level shell and tube heat exchanger 32; the steam-sealing mixing chamber 26 is connected to the first-level shell and tube heat exchanger 33 for exhaust, and the gradually expanding section of the steam-sealing diffuser pipe is connected to the second-level shell and tube heat exchanger 32.

[0031] The first-stage exhaust shell and tube heat exchanger 31 is provided with a first-stage exhaust drain port 311; the second-stage shell and tube heat exchanger 32 is provided with a second-stage exhaust port 321 and a second-stage drain port 322; the first-stage steam seal shell and tube heat exchanger 33 is provided with a steam seal leakage port 331 and a steam seal first-stage drain port 332.

[0032] The working process of the device integrating steam jetting, exhaust and steam seal cooling functions of the present invention is as follows: before the steam turbine is started, the condenser is quickly established with a vacuum sufficient to start the steam turbine through the working steam generating pipe 21 and the starting ejector, thereby achieving the purpose of starting the steam turbine. After the steam turbine is started, the starting ejector stops working (actually, it is achieved by cutting off the connection between the working steam pipe and the starting nozzle through a valve). Then, the steam-gas mixture in the steam-gas mixture extraction pipe 22 is condensed through the first-stage ejector and the exhaust first-stage shell and tube heat exchanger 31, and then the steam-gas mixture that has not been condensed in the previous step is further condensed through the second-stage ejector and the second-stage shell and tube heat exchanger 32, that is, the two-stage steam jetting and exhaust function is realized. The specific process is as follows: the steam-gas mixture passes through the first-level mixing chamber 24 and the first-level diffuser and enters the first-level exhaust shell and tube heat exchanger 31 for condensation, and the condensed water flows out through the first-level exhaust drain port 311. The uncondensed steam-gas mixture continues to pass through the second-level mixing chamber 25 and the second-level diffuser and enters the second-level shell and tube heat exchanger 32 for condensation, and the condensed water flows out through the second-level drain port 322. The small amount of uncondensed steam-gas mixture is discharged into the atmosphere through the second-level exhaust port 321.

[0033] In order to make the leakage pipes of the front and rear steam seals of the steam turbine slightly negative pressure, the leakage needs to enter the steam seal first-level shell and tube heat exchanger 33 through the steam seal leakage port 331, and the leakage is first directly condensed in the steam seal first-level tube bundle heat exchanger, and the condensed water flows out through the steam seal first-level drain port 332, and then the uncondensed leakage is condensed again through the steam seal ejector and the second-level shell and tube heat exchanger 32, and at this time the condensed water flows out through the second-level drain port 322, and the small amount of uncondensed steam-gas mixture is discharged into the atmosphere through the second-level exhaust port 321.

[0034] The first-stage ejector, the second-stage ejector, the first-stage shell-and-tube heat exchanger 31 and the second-stage shell-and-tube heat exchanger 32 in the present invention actually form a two-stage steam ejector, realizing the function of steam ejection and exhaustion; and the steam seal ejector, the first-stage shell-and-tube heat exchanger 33 and the second-stage shell-and-tube heat exchanger 32 actually form a steam seal cooler, realizing the function of steam seal cooling; that is, the present invention integrates the functions of steam ejection and steam seal cooling, and when integrating the above functions, the second-stage shell-and-tube heat exchanger 32 and the working steam generating pipe 2 are shared. 1, and because the first-stage exhaust shell and tube heat exchanger 31, the second-stage shell and tube heat exchanger 32 and the first-stage steam-sealed shell and tube heat exchanger 33 are coaxially arranged, the ends of the first-stage exhaust shell and tube heat exchanger 31 and the first-stage steam-sealed shell and tube heat exchanger 33 are both provided with a reflux water chamber 43, so that the three shell and tube heat exchangers can share one circulating water. The above arrangement makes the equipment highly integrated, reduces the occupied plant area, reduces the layout of steam pipes, reduces the layout of circulating water pipes, makes the plant area tidier, and makes the operation more convenient.

[0035] As a preferred embodiment, it is characterized in that the number of the first-stage ejector and the second-stage ejector is two, so as to achieve the purpose of one for use and one for backup, so that the device of the present invention integrating steam injection, exhaust and steam seal cooling functions has higher reliability when in use.

[0036] Preferably, a muffler 7 is connected between the gradually expanding section of the start-up diffuser and the vent pipe 6. Since the start-up ejector needs to work for about half an hour when the steam turbine is started, the noise is very loud, so the muffler can effectively reduce the noise, making the present invention more environmentally friendly.

[0037] Preferably, a safety valve 8 is also provided on the first-stage exhaust shell and tube heat exchanger 31. Since the second-stage shell and tube heat exchanger 32 is connected to the atmosphere through the second-stage exhaust port 321, it can release pressure through the second-stage exhaust port 321, and will not cause the problem of excessive pressure. The first-stage exhaust shell and tube heat exchanger 31 is a relatively closed space, so there may be a problem of excessive pressure and inability to release pressure, thereby causing a safety accident. Therefore, by providing a safety valve 8, pressure can be released when the pressure is too high, ensuring the safety of the device with integrated steam jet exhaust and steam seal cooling functions of the present invention.

[0038] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device integrating steam jet exhaust and steam seal cooling functions, characterized in that: include: The working steam generating pipe, the steam-gas mixture suction pipe, the starting ejector, the first-stage ejector, the second-stage ejector, the steam seal ejector and the shell and tube heat exchanger; the starting ejector includes a starting nozzle, a starting mixing chamber and a starting pressure diffuser; the first-stage ejector includes a first-stage nozzle, a first-stage mixing chamber and a first-stage pressure diffuser; the second-stage ejector includes a second-stage nozzle, a second-stage mixing chamber and a second-stage pressure diffuser; the steam seal ejector includes a steam seal nozzle, a steam seal mixing chamber and a steam seal pressure diffuser; the shell and tube heat exchanger includes an air extraction first-stage shell and tube heat exchanger, a second-stage shell and tube heat exchanger and a second-stage pressure diffuser. and a steam-sealed first-stage shell and tube heat exchanger; the first-stage exhaust shell and tube heat exchanger is connected to the second-stage shell and tube heat exchanger through an inlet and outlet water chamber, and the second-stage shell and tube heat exchanger is connected to the first-stage steam-sealed shell and tube heat exchanger through a transition water chamber; the first-stage exhaust shell and tube heat exchanger, the second-stage shell and tube heat exchanger and the first-stage steam-sealed shell and tube heat exchanger are coaxially arranged, and the second-stage shell and tube heat exchanger is located between the first-stage exhaust shell and tube heat exchanger and the first-stage steam-sealed shell and tube heat exchanger, and the ends of the first-stage exhaust shell and tube heat exchanger and the first-stage steam-sealed shell and tube heat exchanger are both provided with a reflux water chamber; The starting nozzle, the first-level nozzle, the second-level nozzle and the steam seal nozzle are connected to the working steam generating pipe through the steam pipes arranged in parallel; the first-level mixing chamber is connected to the steam-gas mixture suction pipe; the gradually expanding section of the starting diffuser pipe is connected to a vent pipe; the gradually expanding section of the first-level diffuser pipe is connected to the first-level exhaust shell and tube heat exchanger, the second-level mixing chamber is connected to the first-level exhaust shell and tube heat exchanger, and the gradually expanding section of the second-level diffuser pipe is connected to the second-level shell and tube heat exchanger; the steam seal mixing chamber is connected to the first-level steam seal shell and tube heat exchanger, and the gradually expanding section of the steam seal diffuser pipe is connected to the second-level shell and tube heat exchanger; The first-stage exhaust shell and tube heat exchanger is provided with a first-stage exhaust drain port; the second-stage shell and tube heat exchanger is provided with a second-stage exhaust port and a second-stage drain port; the first-stage steam seal shell and tube heat exchanger is provided with a steam seal leakage port and a first-stage steam seal drain port.

2. The device integrating steam jet exhaust and steam seal cooling functions as claimed in claim 1, characterized in that: The bottom of the reflux water chamber is provided with a water chamber drain port, and the top of the reflux water chamber is provided with a water chamber air release port.

3. The device integrating steam jet exhaust and steam seal cooling functions as claimed in claim 1, characterized in that: The number of the primary injectors and the secondary injectors is two.

4. The device integrating steam jet exhaust and steam seal cooling functions as claimed in claim 1, characterized in that: The bottoms of the exhaust first-stage shell and tube heat exchanger, the second-stage shell and tube heat exchanger and the steam-sealed first-stage shell and tube heat exchanger are all provided with brackets.

5. The device integrating steam jet exhaust and steam seal cooling functions as claimed in claim 1, characterized in that: The water inlet of the inlet and outlet water chamber is located at the bottom, and the water outlet of the inlet and outlet water chamber is located at the top.

6. The device integrating steam jet exhaust and steam seal cooling functions as claimed in claim 1, characterized in that: A muffler is also connected between the gradually expanding section of the starting diffuser pipe and the vent pipe.

7. The device integrating steam jet exhaust and steam seal cooling functions as claimed in claim 1, characterized in that: The first-stage exhaust shell and tube heat exchanger is also provided with a safety valve.

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