Dead steam condensation system
By introducing a gas-free condensation system with modules such as axial flow fan into the power generation system, the problem of inefficiency in traditional wet peak condensation systems in high temperature environments is solved, and efficient gas-free condensation and energy-saving and consumption-saving effects are achieved.
Patent Information
- Application Number
- CN202421051802.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-15
- Publication Date
- 2025-03-04
- Estimated Expiration
- 2034-05-15
AI Technical Summary
In high temperature environments, traditional wet peak condensation systems have low secondary heat exchange efficiency and long pipe connections, resulting in excessive power pump power consumption, large water and power consumption, affecting power generation efficiency.
A steam-free condensation system is adopted, including boilers, steam turbines, vertical evaporation condensers and auxiliary condensation devices. Through module vertical tube bundles, axial flow fans, spray systems and circulating water pumps, efficient steam-free condensation is achieved.
The system can choose the operating mode according to the season, save energy, improve heat exchange efficiency, reduce water and electricity consumption, reduce investment and operating costs, and effectively solve the problem of rising steam turbine back pressure in summer.
Smart Images
Figure CN222560694U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a waste steam condensation system and belongs to the technical field of cooling towers. Background Art
[0002] Most thermal power plants in the southern region use a wet condensation system of condenser + hyperbolic cooling tower to condense the steam discharged from the turbine, while a large number of ordinary small-scale waste heat power plants with a wide distribution usually use a wet condensation system of condenser + mechanical ventilation cooling tower. The functions of the mechanical ventilation cooling tower and the hyperbolic cooling tower are the same, both of which are to dissipate the cooling water required for the condenser to condense the steam and release the heat into the atmosphere.
[0003] Summer is also the time of the year when electricity consumption is the highest. Generators need to operate at full load to meet the electricity demand of residents and businesses. The high temperature environment causes the temperature of the ambient air and circulating cooling water around the cooling tower to rise. The condenser + cooling tower condensation system cannot condense all the exhaust steam in a timely and effective manner. The unit has a high back pressure, which causes the unit to be unable to operate at full load, affecting the power generation efficiency of the power plant. The traditional solution is to add a set of exhaust steam auxiliary condensation system - peak cooling system on the basis of the original air cooling system. At present, the wet peak cooling system is more commonly used, that is, the condenser + cooling tower combination. However, the wet peak cooling system is a secondary heat exchange system with low heat exchange efficiency. In addition, due to the long pipeline connection, the water pump power is too large, so the water consumption and power consumption are large. The promotion in water-scarce areas in the north is subject to certain restrictions.
[0004] Therefore, it is urgent to propose an exhaust steam condensation system to solve the above technical problems. Utility Model Content
[0005] In order to overcome the deficiencies in the prior art, the utility model provides a brief overview of the utility model below to provide a basic understanding of certain aspects of the utility model. It should be understood that this overview is not an exhaustive overview of the utility model. It is not intended to determine the key or important parts of the utility model, nor is it intended to limit the scope of the utility model.
[0006] The technical solution of this utility model:
[0007] A waste steam condensing system comprises a boiler, a steam turbine, a vertical evaporative condenser, a generator and an auxiliary condensing device, wherein the boiler, the steam turbine and the generator are connected in sequence to form a power generation system, and the steam turbine is connected with the vertical evaporative condenser and the auxiliary condensing device arranged in parallel to form a cooling pipeline system; the auxiliary condensing device comprises a condenser and a cooling tower, one end of the tube side of the condenser is connected to the turbine exhaust pipe of the steam turbine, and the shell side of the condenser is cyclically connected to the cooling tower; the vertical evaporative condenser comprises a modular vertical A tube bundle, an axial flow fan, a spray system, a circulating water pump, a stuffing bin, a water collecting tray, a second air duct chamber and a first air duct chamber; one side of the interior of the box is provided with a modular vertical tube bundle and a stuffing bin in sequence from top to bottom; the nozzle of the spray system is fixedly arranged and connected at the upper part of the box; the other side of the interior of the box is provided with an axial flow fan, a second air duct chamber and a first air duct chamber in sequence from top to bottom; a water collecting tray is provided at the bottom of the box, and the water collecting tray is connected to the spray system through a circulating water pump; one end of the modular vertical tube bundle is connected to the turbine exhaust pipe of the steam turbine.
[0008] Preferably, the first air duct chamber is a square inner cavity, the second air duct chamber is a trapezoidal inner cavity which is narrow at the top and wide at the bottom, and a water retaining filler is arranged between the second air duct chamber and the first air duct chamber.
[0009] Preferably: an installation port is provided at the upper portion of one side of the box body, a plurality of evenly arranged modular vertical tube bundles are installed into the box body through the installation port, the tube paths of the plurality of modular vertical tube bundles are arranged in parallel, the spray system is located on the upper outer side of the modular vertical tube bundle, a spray system is arranged between adjacent modular vertical tube bundles, and the nozzles of the spray system face the modular vertical tube bundles on both sides, so as to spray water to cool the modular vertical tube bundles.
[0010] Preferably, the number of the modular vertical tube bundles is four, PVC fillers or wet curtains are arranged between adjacent modular vertical tube bundles, the number of the spray systems is three, and the spray systems are located above the PVC fillers or wet curtains.
[0011] Preferably: it also includes a condensate tank, water treatment equipment, a low-pressure heater, a deaerator, a feed water pump and a high-pressure heater; the other end of the condenser tube and the other end of the modular vertical tube bundle are connected to the condensate tank inlet; the condensate tank outlet and the water treatment equipment outlet are both connected to the low-pressure heater; the low-pressure heater, deaerator, feed water pump, high-pressure heater and boiler are connected in sequence to form a water supply pipeline system.
[0012] Preferably, a superheater is also included, the boiler, the superheater and the steam turbine are connected in sequence through pipelines, and the steam turbine is fixedly connected to the rotor of the generator.
[0013] Preferably, the condenser and the modular vertical tube bundle are connected to the steam turbine through a steam turbine exhaust pipe, and a regulating valve is provided between the modular vertical tube bundle and the steam turbine exhaust pipe.
[0014] The utility model has the following beneficial effects:
[0015] The utility model can select different operation modes according to different conditions in winter and summer, saving energy and having high heat exchange efficiency;
[0016] The utility model can collect condensed water and use it for circulation of the exhaust steam condensation system, thereby reducing water consumption;
[0017] The second air duct chamber of the utility model adopts a contraction design, which is conducive to extracting the air inside the box with minimum resistance, avoiding air bypass affecting the formation of a negative pressure cavity, and realizing efficient operation of the axial flow fan. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a structural schematic diagram of an exhaust steam condensation system;
[0019] Figure 2 It is a structural diagram of a vertical evaporative condenser.
[0020] In the figure: 1-boiler, 2-superheater, 3-steam turbine, 4-vertical evaporative condenser, 5-condensate tank, 6-water treatment equipment, 7-low-pressure heater, 8-deaerator, 9-feedwater pump, 10-high-pressure heater, 11-generator, 12-steam turbine exhaust pipe, 13-condenser, 14-cooling tower, 4-1-modular vertical tube bundle, 4-2-axial flow fan, 4-3-spraying system, 4-4-circulating water pump, 4-5-stuffing bin, 4-6-water collecting tray, 4-7-second air duct chamber, 4-8-first air duct chamber. DETAILED DESCRIPTION
[0021] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is described below by specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the utility model. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the utility model.
[0022] The connection mentioned in the present invention is divided into fixed connection and detachable connection. The fixed connection is a non-detachable connection, including but not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but is not limited to conventional detachable methods such as threaded connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can always be found in the existing connection methods to achieve the function. Those skilled in the art can choose according to their needs. For example: choose welding connection for fixed connection and hinge connection for detachable connection.
[0023] Specific implementation method 1: Combination Figure 1-Figure 2 The embodiment of the present invention is described. A waste steam condensation system of the embodiment of the present invention comprises a boiler 1, a steam turbine 3, a vertical evaporative condenser 4, a generator 11 and an auxiliary condensing device. The boiler 1, the steam turbine 3 and the generator 11 are connected in sequence to form a power generation system. The steam turbine 3 is connected with the vertical evaporative condenser 4 and the auxiliary condensing device arranged in parallel to form a cooling pipeline system. The auxiliary condensing device comprises a condenser 13 and a cooling tower 14. One end of the tube side of the condenser 13 is connected to the turbine exhaust pipe 12 of the steam turbine 3. The shell side of the condenser 13, the circulating pump and the cooling tower 14 are connected in sequence to form an auxiliary condensing circuit circulation system. The vertical evaporative condenser 4 comprises a modular vertical tube bundle 4-1, an axial flow fan 4-2, a spray system 4-3, a circulating water pump 4-4, a stuffing bin 4-5, a water collecting tray 4-6, a second air duct chamber 4-7 and a first air duct chamber 4-8. The modular vertical tube bundle 4-1, A filling bin 4-5 and a nozzle of a spray system 4-3 are fixedly connected at the upper part of the box body, and an axial flow fan 4-2, a second air duct chamber 4-7 and a first air duct chamber 4-8 are fixedly arranged on the other side of the box body in sequence from top to bottom. A water collecting tray 4-6 is arranged at the bottom of the box body, and the water collecting tray 4-6 is connected to the spray system 4-3 through a circulating water pump 4-4. One end of the modular vertical tube bundle 4-1 is connected to the turbine exhaust pipe 12 of the steam turbine 3, and the water collecting tray 4-6 is located below the first air duct chamber 4-8 and the filling bin 4-5. The utility model can select different operating modes according to different situations (temperatures), save energy, and has high heat exchange efficiency. There is only one heat exchange in the entire heat exchange process, and no long pipes are required for connection, and no high-power water pumps and fans are required. The floor space occupied is smaller than that of wet evaporative cooling, and the summer peak load-shaving and summer survival capabilities can be improved. The investment cost and operating cost of the utility model are both low, and the cooling effect of the traditional wet cooling system can be fully achieved.
[0024] Specific implementation method 2: Combination Figure 1-Figure 2 The present embodiment is described. The present embodiment is a kind of exhaust steam condensation system, the first air duct chamber 4-8 is a square inner cavity, the second air duct chamber 4-7 is a trapezoidal inner cavity which is narrow at the top and wide at the bottom, and a water retaining filler is arranged between the second air duct chamber 4-7 and the first air duct chamber 4-8; the second air duct chamber 4-7 adopts a contraction design, and is finally connected with the axial flow fan 4-2. This design is conducive to extracting the air inside the box body with minimum resistance, avoiding the formation of vortex flow of air inside the second air duct chamber 4-7 and the first air duct chamber 4-8, affecting the formation of negative pressure cavity, and realizing efficient operation of the axial flow fan 4-2.
[0025] Specific implementation method three: Combination Figure 1-Figure 2The embodiment of the present invention is described. In the embodiment of the present invention, an exhaust steam condensation system has an installation port at the upper part of one side of the box body. A plurality of evenly arranged modular vertical tube bundles 4-1 are installed into the box body through the installation port. The installation, repair and maintenance are convenient. The tube paths of the plurality of modular vertical tube bundles 4-1 are arranged in parallel. The spray system 4-3 is located at the upper part of the modular vertical tube bundle 4-1. The spray system 4-3 is arranged between adjacent modular vertical tube bundles 4-1. The nozzles of the spray system 4-3 face the modular vertical tube bundles 4-1 on both sides, and are used to spray water to cool the modular vertical tube bundles 4-1. Part of the exhaust steam enters the modular vertical tube bundle 4-1 through the steam inlet pipe, exchanges heat with the spray water outside the modular vertical tube bundle 4-1, and the exhaust steam is condensed into liquid water, which is collected in the condensation water tank 5 through the condensation water pipe; the spray water temperature rises after absorbing the exhaust steam heat, and transfers the heat to the air through contact with the heat dissipation filler in the filler bin 4-5, passes through the first air duct chamber 4-8 and the second air duct chamber 4-7, and is carried out of the equipment by the axial flow fan 4-2. The cooled spray water is collected in the bottom water collection tray 4-6, and finally driven again by the water pump 4-4 to the spray system 4-3, completing a cycle.
[0026] Specific implementation method four: Combination Figure 1-Figure 2 The present embodiment is described. The present embodiment is a waste steam condensation system. The number of the modular vertical tube bundles 4-1 is four. PVC fillers or wet curtains are arranged between adjacent modular vertical tube bundles 4-1. The number of the spray systems 4-3 is three. The spray systems 4-3 are located directly above the PVC fillers or wet curtains. The modular vertical tube bundles 4-1 adopt a modular design. According to the size of different waste steam condensation amounts, several sets of modular vertical tube bundles can be arranged in a single evaporative condenser. In this embodiment, 4 sets of modular vertical tube bundles are included. The inlets between the modular vertical tube bundles are connected to the first mother pipe, and the outlets are connected to the second mother pipe. , implement parallel operation effect; in addition, PVC fillers or wet curtains filled between adjacent modular vertical tube bundles 4-1 avoid air short circuit. At the same time, in order to increase the cooling effect of circulating cooling water, spray water is also distributed on the fillers between adjacent tube bundles, so that the contact area between spray water and air is increased; each modular vertical tube bundle 4-1 is composed of a number of heat exchange tubes, which can be round tubes, elliptical tubes, finned tubes or twisted tubes. The heat exchanger is arranged in the phase change room (box), and the heat exchange tubes are arranged vertically. The purpose is to allow the condensate to quickly discharge the heat exchanger, reduce the pressure in the heat exchange tube, reduce the back pressure of the unit, and improve the power generation efficiency of the steam turbine.
[0027] Specific implementation method five: Combination Figure 1-Figure 2The present embodiment is described. A waste steam condensation system of the present embodiment also includes a condensate tank 5, a water treatment device 6, a low-pressure heater 7, a deaerator 8, a feed water pump 9 and a high-pressure heater 10. The other end of the tube path of the condenser 13 and the other end of the modular vertical tube bundle 4-1 are connected to the inlet of the condensate tank 5. The outlet of the condensate tank 5 and the outlet of the water treatment device 6 are connected to the low-pressure heater 7. The low-pressure heater 7, the deaerator 8, the feed water pump 9, the high-pressure heater 10 and the boiler 1 are connected in sequence to form a water supply pipeline system. The spray water of the present invention is evenly distributed on the outer surface of the modular vertical tube bundle 4-1 to form a water film. The waste steam discharged from the steam turbine 3 enters the modular vertical tube bundle 4-1 through the steam turbine exhaust pipe 12 and is connected to the water film outside the modular vertical tube bundle 4-1. Heat exchange is carried out, and the exhaust steam is taken away with heat, condensed from gas to liquid, and sent back to the turbine 3 by the feed water pump 9. The water film outside the modular vertical tube bundle 4-1 absorbs the heat of the exhaust steam and its temperature rises, and exchanges heat and mass with the air driven by the axial flow fan 4-2. Part of the cooling water evaporates and enters the air and is carried out of the box, so that the temperature of the spray water drops and gathers in the water collecting tray 4-6 at the bottom of the box, and is finally driven again by the circulating water pump 4-4 to re-enter the spray system 4-3; the entire heat exchange process of the exhaust steam and the spray water undergoes one heat exchange; the utility model can also only open the axial flow fan 4-2, close the circulating water pump 4-4, drain the spray water in the water collecting tray 4-6, and operate in dry mode under the condition of low ambient temperature in winter, thereby avoiding the problem of antifreeze of spray water in winter.
[0028] Specific implementation method six: Combination Figure 1-Figure 2 To explain this embodiment, a waste steam condensation system of this embodiment further includes a superheater 2. The boiler 1, the superheater 2, and the steam turbine 3 are connected in sequence through pipelines, and the steam turbine 3 is fixedly connected to the rotor of the generator 11.
[0029] Specific implementation method seven: Combination Figure 1-Figure 2 The present embodiment is described as a waste steam condensation system of the present embodiment, wherein the condenser 13 and the modular vertical tube bundle 4-1 are connected to the steam turbine 3 through the steam turbine exhaust pipe 12, a regulating valve is provided between the modular vertical tube bundle 4-1 and the steam turbine exhaust pipe 12, and no regulating valve is provided between the condenser 13 and the steam turbine exhaust pipe 12.
[0030] The utility model is equipped with a condenser + cooling tower; Figure 1It can be seen that the high-temperature and high-pressure water vapor generated by the boiler 1 enters the steam turbine 3 for expansion and work, and then enters the condenser 13 and the vertical evaporative condenser 4 through the steam turbine exhaust pipe 12 for condensation and heat dissipation. Through the adjustment of the valve (regulating valve), a part (about 80%) of the exhaust steam enters the condenser, and the other part (about 20%) of the exhaust steam enters the evaporative condenser. After the exhaust steam is condensed and turned into liquid water again, it is gathered in the condensate tank 5, and then after being treated by the low-pressure heater 7 and the deaerator 8, it is sent back to the high-pressure heater 10 by the feed water pump 9, and then sent back to the boiler 1 after heating, completing a cycle; because the circulating water will be lost during the flow process, it needs to be supplemented, and the water treatment equipment 6 is connected to the external waterway to treat the supplementary water entering the system, and then enters the pipeline system after merging with the condensed liquid water;
[0031] On the basis of not affecting the original boiler 1, the generator set (power generation system) and the condenser 13 and other main components, by adding a branch pipe in the steam turbine exhaust pipe 12, part of the exhaust steam of the steam turbine passes through the newly installed branch pipe, enters the modular vertical tube bundle 4-1 from the steam inlet header of the evaporative condenser 4, and absorbs heat by evaporation of the water film on the outer surface of the modular vertical tube bundle 4-1 to be condensed, and the condensed water is collected in the condensed water tank 5 through the pipeline, and after merging with the condensed water of the condenser 13 and being deoxygenated, it returns to the boiler 1;
[0032] The utility model is easy to implement, and there is no need to change the original power generation system. Only a branch pipe is added to the steam turbine exhaust pipe 12 and the condenser pipe 13 to connect the evaporative condenser 4, and the amount of exhaust steam entering the evaporative condenser 4 is adjusted by the opening of the valve, thereby realizing system transformation and saving costs.
[0033] During winter operation, the regulating valve is closed, and all the exhaust steam discharged from the steam turbine 3 enters the condenser 13 through the steam turbine exhaust pipe 12. The heat of the exhaust steam is taken away by the circulating cooling water, and the exhaust steam is condensed into liquid and collected in the condensation water tank 5. After treatment, it returns to the boiler 1. The circulating cooling water after absorbing heat transfers the heat to the surrounding air through the cooling tower 14. At this time, the evaporative condenser 4 can meet the power generation demand without running.
[0034] During summer operation, part of the exhaust steam discharged by the steam turbine 3 enters the condenser 13 through the exhaust pipe 12, and the heat of the exhaust steam is taken away by the circulating cooling water, so that it is condensed into liquid and collected in the condensation water tank 5; the remaining exhaust steam enters the evaporative condenser 4 through the newly installed branch pipe, and is condensed into liquid water and collected in the condensation water tank 5, and then all the condensed liquid is returned to the boiler 1 after being processed; the evaporative condenser 4 plays the role of auxiliary condensation, which solves the problem that the ambient temperature is high in summer, the heat exchange performance of the condenser + cooling tower decreases, causing the back pressure of the steam turbine to increase and the unit cannot generate electricity at full load, and can reduce the power consumption of the water pump and save electricity;
[0035] In addition, since the cooling tower is an open system, the circulating cooling water is in direct contact with the surrounding atmosphere and is easily contaminated by dust. It is also easy to produce bacteria and algae when exposed to direct sunlight. When the contaminated cooling water flows through the condenser, it will cause scaling of the pipes, resulting in increased flow resistance. In severe cases, it may even corrode the pipes, causing equipment leakage, causing the equipment to shut down and unable to operate. Therefore, using the evaporative condenser 4 as a supplement to the condenser + cooling tower can still meet the needs of turbine exhaust condensation when the condenser performance decreases.
[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.
[0037] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.
Claims
1. A waste steam condensation system, comprising a boiler (1), a steam turbine (3), a vertical evaporative condenser (4), a generator (11) and an auxiliary condensing device, wherein the boiler (1), the steam turbine (3) and the generator (11) are connected in sequence, and the steam turbine (3) is connected to the vertical evaporative condenser (4) and the auxiliary condensing device which are arranged in parallel; characterized in that: The auxiliary condensing device comprises a condenser (13) and a cooling tower (14); the tube side of the condenser (13) is connected to the steam turbine (3); the shell side of the condenser (13) is cyclically connected to the cooling tower (14); the vertical evaporative condenser (4) comprises a modular vertical tube bundle (4-1), an axial flow fan (4-2), a spray system (4-3), a circulating water pump (4-4), a stuffing bin (4-5), a water collecting tray (4-6), a second air duct chamber (4-7) and a first air duct chamber (4-8); A modular vertical tube bundle (4-1) and a stuffing bin (4-5) are sequentially arranged on one side of the box body from top to bottom, and a spray system (4-3) is arranged and connected at the upper part of the box body. An axial flow fan (4-2), a second air duct chamber (4-7), and a first air duct chamber (4-8) are sequentially arranged on the other side of the box body from top to bottom. A water collecting pan (4-6) is arranged at the bottom of the box body. The water collecting pan (4-6) is connected to the spray system (4-3) through a circulating water pump (4-4), and the modular vertical tube bundle (4-1) is connected to the steam turbine (3).
2. The exhaust steam condensation system according to claim 1, characterized in that: The first air duct chamber (4-8) is a square inner cavity, and the second air duct chamber (4-7) is a trapezoidal inner cavity that is narrow at the top and wide at the bottom.
3. The exhaust steam condensation system according to claim 1, characterized in that: The upper part of one side of the box body is provided with an installation opening, and a plurality of evenly arranged modular vertical tube bundles (4-1) are installed into the box body through the installation opening. The tube paths of the plurality of modular vertical tube bundles (4-1) are arranged in parallel. The spray system (4-3) is located at the upper part of the modular vertical tube bundle (4-1). The spray system (4-3) is arranged between adjacent modular vertical tube bundles (4-1), and the spray heads of the spray system (4-3) face the modular vertical tube bundles (4-1) on both sides.
4. The exhaust steam condensation system according to claim 3, characterized in that: The number of the modular vertical tube bundles (4-1) is four, PVC fillers or wet curtains are arranged between adjacent modular vertical tube bundles (4-1), the number of the spray systems (4-3) is three, and the spray systems (4-3) are located above the PVC fillers or wet curtains.
5. The exhaust steam condensation system according to claim 4, characterized in that: It also includes a condensate tank (5), a water treatment device (6), a low-pressure heater (7), a deaerator (8), a feed water pump (9) and a high-pressure heater (10); the tube side of the condenser (13) and the modular vertical tube bundle (4-1) are connected to the condensate tank (5); the condensate tank (5) and the water treatment device (6) are both connected to the low-pressure heater (7); the low-pressure heater (7), the deaerator (8), the feed water pump (9), the high-pressure heater (10) and the boiler (1) are connected in sequence to form a water supply pipeline system.
6. The exhaust steam condensation system according to claim 1, characterized in that: It also includes a superheater (2). The boiler (1), the superheater (2) and the steam turbine (3) are connected in sequence through pipelines, and the steam turbine (3) is connected to the generator (11).
7. The exhaust steam condensation system according to claim 1, characterized in that: The condenser (13) and the modular vertical tube bundle (4-1) are connected to the steam turbine (3) via a steam turbine exhaust pipe (12), and a regulating valve is provided between the modular vertical tube bundle (4-1) and the steam turbine exhaust pipe (12).