A high-low pressure heater double-row arrangement heating feed water system for coal-fired power plants

Abstract

The utility model provides a kind of coal-fired power plant high-low pressure heater double-row arrangement heating feedwater system, high pressure heater pipeline is equipped with two parallel high pressure heater pipelines;The inlet of high pressure heater pipeline is equipped with pneumatic control tee valve, pneumatic control tee valve and each row high pressure heater pipeline junction is equipped with normally open sluice valve, check valve is equipped at the outlet of each row high pressure heater pipeline;Each row high pressure heater pipeline is equipped with multiple high pressure heaters, remote pressure detection point and remote temperature detection point are equipped at the inlet end of each high pressure heater, local temperature detection point is equipped at the outlet end;Discharge port is further equipped in each row high pressure heater pipeline, normally closed stop valve is equipped on the pipeline of discharge port.The parallel structure of high pressure heater is set, when a set in parallel structure fails, another set can maintain operation, avoid the damage of high pressure heater and low pressure heater and affect overall energy consumption.Suitable for extremely high energy consumption control requirement working condition.

Description

Technical Field

[0001] This utility model relates to the field of waste heat utilization in thermal power generation systems, and in particular to a double-row arrangement of high and low pressure heaters for heating water in a coal-fired power plant. Background Technology

[0002] High-pressure and low-pressure heaters are key equipment in the feedwater heating system of thermal power plants. They utilize partially worked steam extracted from the turbine to heat the boiler feedwater, thereby improving the overall thermal efficiency of the power plant. The low-pressure heater heats the condensate from the condenser, preheating it before it enters the deaerator to recover heat and reduce the steam consumption of the deaerator. Simultaneously, the introduction of low-pressure extracted steam into the low-pressure heater reduces the amount of steam discharged into the condenser, lowering the steam velocity and pressure on the turbine's last-stage blades, reducing aerodynamic losses and mechanical wear, extending the service life of the last-stage blades, and lowering the heat exchange load on the condenser. The low-pressure heater operates at a heating temperature of approximately 60℃-320℃ and a pressure of approximately 0.02MPa-1MPa. The high-pressure heater further heats the boiler feedwater after the deaerator, increasing the water temperature entering the boiler and reducing boiler fuel consumption. The outlet temperature of the high-pressure heater is 300℃-470℃, and the pressure is approximately 2MPa to over 10MPa. The problem is that thermal power generation projects supporting new energy sources require thermal power plants to respond quickly and flexibly to grid dispatch instructions. Failures in both high-pressure and low-pressure heaters can prevent coal-fired power generating units from recovering heat, leading to a significant increase in energy consumption, a decrease in boiler response rate, and substantial losses. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a dual-row arrangement of high and low pressure heaters for heating feedwater in a coal-fired power plant. This system can prevent a significant increase in unit energy consumption, a decrease in boiler response rate, and substantial losses caused by the failure of the high-pressure heater and the low-pressure heater. When one set of heaters fails, the other set can continue to operate without affecting normal production.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is: a double-row arrangement heating water system for high and low pressure heaters in a coal-fired power plant, wherein the high pressure heater pipeline is provided with two parallel rows of high pressure heater pipelines; The inlet of the high-pressure heater pipeline is equipped with a pneumatic three-way valve, the connection between the pneumatic three-way valve and each high-pressure heater pipeline is equipped with a normally open gate valve, and the outlet of each high-pressure heater pipeline is equipped with a check valve. Each high-pressure heater pipeline is equipped with multiple high-pressure heaters. Each high-pressure heater has a remote pressure detection point and a remote temperature detection point at its inlet end, and a local temperature detection point at its outlet end. Each column of high-pressure heater pipeline is also equipped with a discharge port, and the discharge port pipeline is equipped with a normally closed shut-off valve.

[0005] In the preferred embodiment, an external steam cooler for the high-pressure feedwater heater is installed downstream of the high-pressure heater pipeline, and a remote pressure detection point, a remote temperature detection point, and a local temperature detection point are installed upstream of the external steam cooler for the high-pressure feedwater heater. A remote temperature detection point and a local temperature detection point are set downstream of the external steam cooler of the high-pressure feedwater heater.

[0006] In the preferred embodiment, the pipeline of the external steam cooler for the high-pressure feedwater heater is equipped with a throttling orifice plate in parallel.

[0007] In the preferred embodiment, a low-pressure heater pipeline is provided between the outlet pipe of the gas seal cooler and the condensate makeup water pipeline and the deaerator. The low-pressure heater pipeline is heated through the condenser circuit, and the heating or de-heating state is switched by an electrically controlled normally closed valve.

[0008] In the preferred embodiment, the condenser circuit is equipped with multiple condensers, one of which is connected in series with a condensate cooler; The condensate pump is connected to the shell side of the condenser.

[0009] In the preferred embodiment, a local temperature detection point is provided on the low-pressure heater pipeline; Remote pressure detection points are set downstream of each condenser and condensate cooler, and remote temperature detection points are set upstream and downstream of each condenser and condensate cooler.

[0010] In a preferred embodiment, a first low-pressure heater pipeline and a second low-pressure heater pipeline are also provided downstream of the condenser circuit on the low-pressure heater pipeline. The first low-pressure heater pipeline is equipped with two parallel rows of low-pressure heater groups; the second low-pressure heater pipeline is equipped with two parallel rows of low-pressure heaters.

[0011] In the preferred embodiment, each row of low-pressure heaters in the first low-pressure heater pipeline is provided with two low-pressure heaters, and the two low-pressure heaters are connected to the outlet of the low-pressure heater drain pump. The downstream of each row of low-pressure heaters is connected to the inlet of the flue gas waste heat device pipeline. A remote pressure detection point is provided downstream of each low-pressure heater, at least one remote temperature detection point is provided upstream of each low-pressure heater, and two remote temperature detection points are provided downstream of each low-pressure heater.

[0012] In the preferred embodiment, each low-pressure heater group is provided with an electrically controlled normally open valve downstream, and the first low-pressure heater pipeline is also provided with parallel straight pipelines, on which an electrically controlled normally closed valve is provided. Each column of the second low-pressure heater pipeline is equipped with one low-pressure heater; The first low-pressure heater pipeline is connected to two rows of low-pressure heaters in the second low-pressure heater pipeline via an electrically controlled three-way valve.

[0013] In a preferred embodiment, the upstream of each column of the second low-pressure heater is connected to the outlet of the flue gas waste heat device pipeline, and the downstream is connected to the condensate to boiler drain pipe. One remote temperature detection point is set up upstream of the low-pressure heater, and two remote temperature detection points and one remote pressure detection point are set up downstream of the low-pressure heater.

[0014] The second low-pressure heater pipeline is also equipped with a parallel straight-through pipeline, which is equipped with an electrically controlled normally closed valve.

[0015] This invention provides a dual-row arrangement of high and low pressure heaters for heating feedwater in a coal-fired power plant. The system features a parallel structure of high-pressure and low-pressure heaters, ensuring that if one set fails, the other can continue operating, preventing damage to either heater from affecting overall energy consumption. This is suitable for applications with extremely high requirements for operational reliability and energy consumption control, such as main power plants and heating power plants. Two heaters of the same extraction stage serve as backups for each other. When one heater requires maintenance due to tube sheet leakage, severe tube bundle scaling, or other faults, the faulty section can be isolated via valves, while the other heater continues normal operation. The number of regenerative stages remains unchanged, and the unit can operate at 100% rated load, completely preventing increased energy consumption due to heater failure. This optimizes operational economy, improves thermodynamic cycle efficiency, reduces energy loss, and ensures grid power supply stability. This solution is particularly crucial for megawatt-class main power units. The low-pressure heater pipeline is divided into two parallel sections connected in series, increasing the flexibility of valve isolation operations throughout the pipeline. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the high-pressure heater pipeline of this utility model.

[0017] Figure 2 This is a schematic diagram of the structure of the low-pressure heater pipeline of this utility model.

[0018] In the diagram: Remote pressure detection point 1, remote temperature detection point 2, local temperature detection point 3, hydraulic three-way valve 4, external steam cooler for high-pressure feedwater heater 5, orifice plate 6, pneumatic three-way valve 7, normally open gate valve 8, high-pressure heater 9, normally closed shut-off valve 10, discharge port 11, check valve 12, electrically controlled normally open valve 13, superheater desuperheating water pipeline 14, automatic control device 15, economizer inlet header 16, boiler flue gas waste heat utilization device outlet 17, pneumatic normally closed valve 18, pressurized drain header 19, outer sleeve 20. 21. Deaerator, 22. Overflow unit drain pipe, 23. Pneumatically controlled normally open valve, 24. Gas seal cooler outlet pipe, 25. Condensate makeup water pipe, 26. Normally closed gate valve, 27. Drain cooler, 28. Condenser, 29. Electrically controlled three-way valve, 30. Electrically controlled normally closed valve, 31. Condensate to boiler drain pipe, 32. Low-pressure heater, 33. Flue gas waste heat device pipe outlet, 34. Flue gas waste heat device pipe inlet, 35. Low-pressure heater drain pump outlet, 36. Condensate pump, 37. First low-pressure heater pipe, 38. Second low-pressure heater pipe. Detailed Implementation

[0019] Example 1: like Figure 1 In a coal-fired power plant, a dual-row arrangement of high and low pressure heaters is provided for heating water supply, wherein the high pressure heater pipeline has two parallel rows of high pressure heater pipelines. The inlet of the high-pressure heater pipeline is equipped with a pneumatically controlled three-way valve 7. The connection between the pneumatically controlled three-way valve 7 and each high-pressure heater pipeline is equipped with a normally open gate valve 8. A check valve 12 is installed at the outlet of each high-pressure heater pipeline. With this structure, the two high-pressure heater pipelines can switch between duplex, one-on-one standby, and dual standby working modes. The one-on-one standby mode is for normal working conditions, the duplex mode is for high-load working conditions, and the dual standby mode is less commonly used, mainly to deal with the situation where both high-pressure heater pipelines fail.

[0020] Each high-pressure heater pipeline is equipped with multiple high-pressure heaters 9. Each high-pressure heater 9 has a remote pressure detection point 1 and a remote temperature detection point 2 at its inlet end and a local temperature detection point 3 at its outlet end. The remote pressure detection point 1 and the remote temperature detection point 2 are used to provide data to the central control center via the network, while the local temperature detection point 3 is used to provide data to on-site inspection personnel.

[0021] Each column of high-pressure heater pipeline is also equipped with a discharge port 11, and a normally closed shut-off valve 10 is installed on the pipeline of the discharge port 11.

[0022] Preferred solutions include Figure 1 Downstream of the high-pressure heater pipeline, there is an external steam cooler 5 for the high-pressure feedwater heater. Upstream of the external steam cooler 5, there are a remote pressure detection point 1, a remote temperature detection point 2, and a local temperature detection point 3. Downstream of the external steam cooler 5 of the high-pressure feedwater heater, there is a remote temperature detection point 2 and a local temperature detection point 3.

[0023] In a preferred embodiment, the pipeline of the external steam cooler 5 for the high-pressure feedwater heater is provided with a throttling orifice plate 6 in parallel, thereby enabling adaptive adjustment of the working load of the external steam cooler 5.

[0024] Example 2: Preferred solutions include Figure 2 In the process, a low-pressure heater pipeline is provided between the outlet pipe 24 of the gas seal cooler and the condensate makeup water pipeline 25 and the deaerator 21. The low-pressure heater pipeline is heated through the condenser circuit, and the heating or de-heating state is switched by an electrically controlled normally closed valve 30.

[0025] Preferred solutions include Figure 2 In the middle, the condenser circuit is equipped with multiple condensers 28, one of which is connected in series with a condensate cooler 27; The shell side of condenser 28 is connected to condensate pump 36.

[0026] In the preferred embodiment, a local temperature detection point 3 is provided on the low-pressure heater pipeline; Remote pressure detection point 1 is provided downstream of each condenser 28 and condensate cooler 27, and remote temperature detection point 2 is provided upstream and downstream of each condenser 28 and condensate cooler 27.

[0027] Preferred solutions include Figure 2 Downstream of the condenser circuit on the low-pressure heater pipeline, there is also a first low-pressure heater pipeline 37 and a second low-pressure heater pipeline 38. The first low-pressure heater pipeline 37 is provided with two parallel rows of low-pressure heaters 32; the second low-pressure heater pipeline 38 is provided with two parallel rows of low-pressure heaters 32.

[0028] Preferred solutions include Figure 2 In the first low-pressure heater pipeline, each row of low-pressure heaters 32 is equipped with two low-pressure heaters 32. The two low-pressure heaters 32 are connected to the outlet 35 of the low-pressure heater condensate pump. The downstream of each row of low-pressure heaters 32 is connected to the inlet 34 of the flue gas waste heat device pipeline. A remote pressure detection point 1 is provided downstream of each low-pressure heater 32, at least one remote temperature detection point 2 is provided upstream of each low-pressure heater 32, and two remote temperature detection points 2 are provided downstream of each low-pressure heater 32.

[0029] Preferred solutions include Figure 2 In the middle, each of the 32 groups of low-pressure heaters is equipped with an electrically controlled normally open valve 13 downstream, and the first low-pressure heater pipeline is also equipped with parallel straight pipelines, and an electrically controlled normally closed valve 30 is installed on the straight pipelines. Each column of the second low-pressure heater pipeline 38 is equipped with one low-pressure heater 32; The first low-pressure heater line 37 is connected to two rows of low-pressure heaters 32 in the second low-pressure heater line 38 via an electrically controlled three-way valve 29. Setting the low-pressure heater line in two sections improves the flexibility of pipeline valve isolation operation, for example… Figure 2 In the middle, it can be switched to a two-column straight-through mode or a two-column cross-connection mode.

[0030] In a preferred embodiment, the upstream of each column of the second low-pressure heater 32 is connected to the outlet 33 of the flue gas waste heat device pipeline, and the downstream is connected to the condensate to boiler drain pipe 31. One remote temperature detection point 2 is provided upstream of the low-pressure heater 32, and two remote temperature detection points 2 and one remote pressure detection point 1 are provided downstream of the low-pressure heater 32.

[0031] The second low-pressure heater pipeline is also equipped with a parallel straight-through pipeline, which is equipped with an electrically controlled normally closed valve 30. When both rows of low-pressure heaters in the first and second low-pressure heater pipelines fail, the straight-through pipeline is connected to ensure continuous production.

[0032] The above embodiments are merely preferred technical solutions of this utility model and should not be considered as limitations on this utility model. The embodiments and features described in this application can be arbitrarily combined without conflict. The protection scope of this utility model should be defined as the technical solution described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the protection scope of this utility model.

Claims

1. A double-row arrangement of high and low pressure heaters for a coal-fired power plant, characterized in that: The high-pressure heater pipeline has two parallel rows of high-pressure heater lines; The inlet of the high-pressure heater pipeline is equipped with a pneumatic three-way valve (7), the connection between the pneumatic three-way valve (7) and each high-pressure heater pipeline is equipped with a normally open gate valve (8), and the outlet of each high-pressure heater pipeline is equipped with a check valve (12). Each high-pressure heater pipeline is equipped with multiple high-pressure heaters (9). Each high-pressure heater (9) has a remote pressure detection point (1) and a remote temperature detection point (2) at the inlet end and a local temperature detection point (3) at the outlet end. Each column of high-pressure heater pipeline is also provided with a discharge port (11), and a normally closed shut-off valve (10) is provided on the pipeline of the discharge port (11).

2. A double-row arrangement of high and low pressure heaters for a coal-fired power plant heating water system according to claim 1, characterized in that: in Downstream of the high-pressure heater pipeline, there is also an external steam cooler (5) for the high-pressure feedwater heater. Upstream of the external steam cooler (5) for the high-pressure feedwater heater, there are remote pressure detection points (1), remote temperature detection points (2) and local temperature detection points (3). Downstream of the external steam cooler (5) of the high-pressure feedwater heater, there is a remote temperature detection point (2) and a local temperature detection point (3).

3. A double-row arrangement of high and low pressure heaters for a coal-fired power plant heating water system according to claim 2, characterized in that: The pipeline of the external steam cooler (5) of the high-pressure feedwater heater is equipped with a throttling orifice plate (6) in parallel.

4. A double-row arrangement of high and low pressure heaters for a coal-fired power plant heating water system according to claim 2, characterized in that: A low-pressure heater pipeline is provided between the outlet pipe (24) of the air-sealed cooler and the condensate makeup water pipeline (25) and the deaerator (21). The low-pressure heater pipeline is heated through the condenser circuit, and the heating or de-heating state is switched by an electrically controlled normally closed valve (30).

5. A double-row arrangement of high and low pressure heaters for a coal-fired power plant heating water system according to claim 4, characterized in that: The condenser circuit is equipped with multiple condensers (28), one of which is connected in series with a condensate cooler (27). The shell side of the condenser (28) is connected to the condensate pump (36).

6. A double-row arrangement of high and low pressure heaters for a coal-fired power plant heating water system according to claim 5, characterized in that: Local temperature detection points are installed in the low-pressure heater pipeline (3); Remote pressure detection points (1) are provided downstream of each condenser (28) and condensate cooler (27), and remote temperature detection points (2) are provided upstream and downstream of each condenser (28) and condensate cooler (27).

7. A dual-row arrangement of high and low pressure heaters for a coal-fired power plant heating feedwater system according to claim 5, characterized in that: the low pressure... Downstream of the condenser circuit on the heater line, there is also a first low-pressure heater line (37) and a second low-pressure heater line (38). The first low-pressure heater pipeline (37) is provided with two parallel rows of low-pressure heaters (32); the second low-pressure heater pipeline (38) is provided with two parallel rows of low-pressure heaters (32).

8. A double-row arrangement of high and low pressure heaters for a coal-fired power plant heating feedwater system according to claim 7, characterized in that: Each row of low-pressure heaters (32) in the first low-pressure heater pipeline is provided with two low-pressure heaters (32). The two low-pressure heaters (32) are connected to the outlet (35) of the low-pressure heater condensate pump. The downstream of each row of low-pressure heaters (32) is connected to the inlet (34) of the flue gas waste heat device pipeline. A remote pressure detection point (1) is provided downstream of each low-pressure heater (32), at least one remote temperature detection point (2) is provided upstream of each low-pressure heater (32), and two remote temperature detection points (2) are provided downstream of each low-pressure heater (32).

9. A double-row arrangement of high and low pressure heaters for a coal-fired power plant heating water system according to claim 8, characterized in that: Each low-pressure heater (32) group is equipped with an electrically controlled normally open valve (13) downstream. The first low-pressure heater pipeline is also equipped with a parallel straight pipeline, and an electrically controlled normally closed valve (30) is provided on the straight pipeline. Each column of the second low-pressure heater pipeline (38) is equipped with one low-pressure heater (32); The first low-pressure heater line (37) is connected to the two rows of low-pressure heaters (32) of the second low-pressure heater line (38) via an electrically controlled three-way valve (29).

10. A double-row arrangement of high and low pressure heaters for a coal-fired power plant heating water system according to claim 9, characterized in that: The upstream of each column of the low-pressure heater (32) in the second low-pressure heater pipeline is connected to the outlet (33) of the flue gas waste heat device pipeline, and the downstream is connected to the condensate to boiler drain pipe (31). One remote temperature detection point (2) is provided upstream of the low-pressure heater (32), and two remote temperature detection points (2) and one remote pressure detection point (1) are provided downstream of the low-pressure heater (32). The second low-pressure heater pipeline is also equipped with a parallel straight pipeline, on which an electrically controlled normally closed valve (30) is installed.

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