A starting steam sharing system for a new ultra-supercritical unit and an old subcritical unit

Abstract

The application discloses a kind of ultra-supercritical new unit and subcritical old unit's starting steam sharing system, including intercommunication ultra-supercritical new unit and subcritical old unit, and the ultra-supercritical new unit includes multiple first auxiliary steam header with starting steam transportation pipeline communication, and the subcritical old unit includes multiple second auxiliary steam header with starting steam transportation pipeline communication, each second auxiliary steam header is communicated with reheating cold section steam supply pipeline, and reheating cold section steam supply pipeline has branch pipeline with starting steam transportation pipeline communication, and first regulating valve station is arranged on branch pipeline.The application can be set without related starting boiler when new unit is built, save cost, improve the linkage between new unit and old unit at the same time, and any one unit in old unit can provide starting steam to new unit, so that the flexibility of the whole plant unit is greatly improved, and the operation reliability of the whole plant unit is also guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of thermal power generation technology, and in particular relates to a start-up steam sharing system for ultra-supercritical new units and subcritical old units. Background Technology

[0002] Currently, in most thermal power plants, to facilitate unified plant layout and interconnection between new and old units, newly built ultra-supercritical units are often expanded adjacent to existing subcritical older units. Due to the significant differences in capacity and unit class between the new and old units, i.e., the large differences in the parameters of their auxiliary steam systems, a matching start-up boiler needs to be set up to provide start-up steam when building a new ultra-supercritical unit. This results in a large initial investment, poor interoperability between the new and old units, and consequently, poor reliability and flexibility of the entire thermal power plant's unit operation, requiring even higher labor costs. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a start-up steam sharing system for new ultra-supercritical units and old subcritical units. When building new units, there is no need to set up a related start-up boiler, saving costs. At the same time, it improves the linkage between new and old units. Start-up steam can be provided to the new unit from any unit in the old unit, which greatly improves the flexibility of the units in the entire plant and ensures the operational reliability of all units in the plant.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A start-up steam sharing system for a new ultra-supercritical unit and a subcritical old unit includes an ultra-supercritical new unit and a subcritical old unit that are interconnected. The ultra-supercritical new unit includes multiple first auxiliary steam headers, each connected to a start-up steam transport pipeline. The subcritical old unit includes multiple second auxiliary steam headers, each connected to a start-up steam transport pipeline. Each second auxiliary steam header is connected to a reheat cold section steam supply pipeline. The reheat cold section steam supply pipeline has a branch pipeline connected to the start-up steam transport pipeline, and a first regulating valve station is installed on the branch pipeline.

[0006] In one embodiment, a second regulating valve station is also provided on the reheat cold section steam supply pipeline. The second regulating valve station is located between the branch pipeline and the second auxiliary steam header. In this embodiment, the steam introduced by the reheat cold section steam of the subcritical old unit is depressurized by the second regulating valve station and then enters the second auxiliary steam header to supply steam to various points of use of the subcritical old unit.

[0007] In one embodiment, the first auxiliary steam header is connected to the starting steam transport pipeline via a first starting pipeline, and the second auxiliary steam header is connected to the starting steam transport pipeline via a second starting pipeline. Both the first starting pipeline and the second starting pipeline are equipped with a first switch valve assembly.

[0008] In one embodiment, a desuperheater station is also connected to the start-up steam transport pipeline. The desuperheater station is located between the first auxiliary steam header and the second auxiliary steam header. In this embodiment, steam is drawn from the first auxiliary steam header and desuperheated by the desuperheater station, enabling the new ultra-supercritical unit to provide start-up steam to the old subcritical unit. That is, any one of the new ultra-supercritical units and the old subcritical units in the entire plant area can provide start-up steam to the other units, further improving the flexibility and operational reliability of the entire plant's units.

[0009] In one embodiment, the desuperheater station includes a second switch valve group installed on the start-up steam transport pipeline and a desuperheating pipeline connected in parallel to the start-up steam transport pipeline. A third switch valve group is installed on the desuperheating pipeline, and a cooling water device connected to the desuperheating pipeline is installed in the third switch valve group.

[0010] In one embodiment, the first regulating valve station includes two first gate valves arranged in series, a first pneumatic regulating valve is provided between the two first gate valves, and a first check valve is also installed between the first regulating valve station and the start-up steam transport pipeline.

[0011] In one embodiment, the second regulating valve station includes an electric gate valve, a second pneumatic regulating valve, and a second check valve arranged in sequence. The electric gate valve is located near the outlet end of the reheat cold section steam, and the second check valve is located near the second auxiliary steam header.

[0012] In one embodiment, both the first switching valve group and the second switching valve group include a third check valve and a second gate valve arranged in series.

[0013] In one embodiment, the third switching valve group includes two third gate valves arranged in series, the cooling water device is connected between the two third gate valves, and a fourth check valve is also provided between the third switching valve group and the start-up steam transport pipeline.

[0014] The beneficial effects of this invention are as follows:

[0015] It enables newly built ultra-supercritical units and older subcritical units within the plant to provide start-up steam to each other, which not only reduces the cost of new units but also improves the operational reliability and flexibility of all units in the plant. Attached Figure Description

[0016] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0017] Figure 1 A schematic diagram of the steam sharing system of the present invention is shown;

[0018] Figure 2 A schematic diagram showing the supply of gas from an old unit to a new unit according to the present invention is shown;

[0019] Figure 3 A schematic diagram showing the new unit of the present invention supplying gas to the old unit is shown;

[0020] Figure 4 A schematic diagram of the structure of the first regulating valve assembly of the present invention is shown;

[0021] Figure 5 A schematic diagram of the structure of the second regulating valve assembly of the present invention is shown;

[0022] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.

[0023] Figure label:

[0024] 1-First auxiliary steam header, 2-Second auxiliary steam header, 3-Reheat cold section steam supply pipeline, 4-First regulating valve station, 5-Second regulating valve station, 6-First start-up pipeline, 7-First switch valve group, 8-Desuperheater station, 9-Second start-up pipeline, 401-First gate valve, 402-First pneumatic regulating valve, 403-First check valve, 501-Electric gate valve, 502-Second pneumatic regulating valve, 503-Second check valve. Detailed Implementation

[0025] The invention will now be further described with reference to the accompanying drawings.

[0026] This invention provides a start-up steam sharing system for new ultra-supercritical units and older subcritical units, such as... Figure 1 As shown, the system includes interconnected ultra-supercritical new units and subcritical old units. The ultra-supercritical new units include multiple first auxiliary steam headers 1, each connected to the start-up steam transport pipeline. The subcritical old units include multiple second auxiliary steam headers 2, each connected to the start-up steam transport pipeline. Each second auxiliary steam header 2 is connected to the reheat cold section steam via a reheat cold section steam supply pipeline 3. The reheat cold section steam supply pipeline 3 also has a branch pipeline connected to the start-up steam transport pipeline, and a first regulating valve station 4 is installed on the branch pipeline.

[0027] It should be noted that, as Figure 1 and Figure 2As shown, in order to meet the power generation demand, a new ultra-supercritical unit is built adjacent to the old subcritical unit in the thermal power plant area. The new ultra-supercritical unit does not require a new start-up boiler. At the same time, the reheat cold section steam can be depressurized through the first regulating valve station 4 on the branch pipeline and then sent to the first auxiliary steam header 1 through the start-up steam transport pipeline. This allows the new ultra-supercritical unit to be started from the old subcritical unit without the need to set up a start-up boiler to match it when building the new unit, saving the construction investment of the unit. At the same time, it makes the new unit more flexible with the old unit and facilitates the staff to coordinate the operation status of the units in the entire plant area.

[0028] In one embodiment, a second regulating valve station 5 is also provided on the reheat cold section steam supply pipeline 3. The second regulating valve station 5 is located between the branch pipeline and the second auxiliary steam header 2. When the subcritical old unit is running, the old unit's own reheat cold section steam supply pipeline 3 can input reheat cold section steam to the second auxiliary steam header 2 to supply steam to various steam consumption points of the subcritical old unit. The introduced reheat cold section steam has a relatively high pressure. The steam introduced by the reheat cold section steam enters the second auxiliary steam header 2 after being depressurized by the second regulating valve station 5.

[0029] Furthermore, such as Figure 1 The steam transport pipeline is also connected to a desuperheater station 8, which is located between the first auxiliary steam header 1 and the second auxiliary steam header 2.

[0030] It should be noted that when the new ultra-supercritical unit is running and the old subcritical unit is not started, steam can be extracted from the first auxiliary steam header 1, de-temperatured by the desuperheater station 8, and then supplied to the old subcritical unit for startup steam. That is, any one of the new ultra-supercritical unit and the old subcritical unit in the entire plant area can supply startup steam to the other units, further improving the flexibility and operational reliability of the entire plant's units.

[0031] Specifically, such as Figure 1 As shown, the desuperheater station 8 includes a second switch valve group installed on the start-up steam transport pipeline and a desuperheating pipeline connected in parallel to the start-up steam transport pipeline. A third switch valve group is installed on the desuperheating pipeline, and a cooling water device connected to the desuperheating pipeline is installed in the third switch valve group.

[0032] It should be noted that when supplying steam to a new ultra-supercritical unit, the start-up steam, after being depressurized, passes through the second switch valve group of the desuperheater station 8 (no desuperheating required) and then reaches the first auxiliary steam header 1 to start the new unit; while when supplying steam to an old unit through the new unit, because the steam parameters of the new unit are higher in temperature, it passes through the desuperheater station 8 and the desuperheating pipeline connected in parallel with the start-up steam transport pipeline, and is desuperheated under the action of the cooling water device before reaching the second auxiliary steam header 2 to start the old unit.

[0033] Specifically, such as Figure 1 and Figure 4 As shown, the first regulating valve station 4 includes two first gate valves 401 arranged in series, a first pneumatic regulating valve 402 is arranged between the two first gate valves 401, and a first check valve 403 is also installed between the first regulating valve station 4 and the start-up steam transport pipeline; that is, the opening and closing of the gas circuit is controlled by the first gate valve 401, the first pneumatic regulating valve 402 reduces the pressure of steam, and the first check valve 403 prevents steam backflow and plays a role in safety isolation.

[0034] like Figure 1 and Figure 5 As shown, the second regulating valve station 5 includes an electric gate valve 501, a second pneumatic regulating valve 502, and a second check valve 503 arranged in sequence. The electric gate valve 501 is located near the outlet end of the reheat cold section steam, and the second check valve 503 is located near the second auxiliary steam header 2. Since the pressure of the reheat cold section steam is relatively high, it is depressurized by the second pneumatic regulating valve 502 and then enters the second auxiliary steam header 2 to start the subcritical old unit.

[0035] In one embodiment, both the first switching valve group 7 and the second switching valve group include a third check valve and a second gate valve arranged in series, and the controller controls the opening and closing of the corresponding pipeline while ensuring the safety of the pipeline.

[0036] In one embodiment, such as Figure 1 As shown, the third switching valve group includes two third gate valves connected in series, a cooling water device is connected between the two third gate valves, and a fourth check valve is also installed between the third switching valve group and the start-up steam transport pipeline.

[0037] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A start-up steam sharing system of a new ultra-supercritical unit and an old subcritical unit, characterized in that, The system comprises ultra-supercritical new units and subcritical old units, the ultra-supercritical new units comprise a plurality of first auxiliary steam headers respectively connected with a start-up steam transportation pipeline, the subcritical old units comprise a plurality of second auxiliary steam headers respectively connected with the start-up steam transportation pipeline, each of the second auxiliary steam headers is connected with a reheated cold section steam supply pipeline, the reheated cold section steam supply pipeline has a branch pipeline connected with the start-up steam transportation pipeline, and a first regulating valve station is arranged on the branch pipeline; The first auxiliary steam headers are connected with the start-up steam transportation pipeline through first start-up pipelines, the second auxiliary steam headers are connected with the start-up steam transportation pipeline through second start-up pipelines, and first switch valve groups are arranged on the first start-up pipelines and the second start-up pipelines; The start-up steam transportation pipeline is further connected with a desuperheater station, and the desuperheater station is located between the first auxiliary steam headers and the second auxiliary steam headers; The desuperheater station comprises second switch valve groups arranged on the start-up steam transportation pipeline and desuperheating pipelines connected in parallel with the start-up steam transportation pipeline, third switch valve groups are arranged on the desuperheating pipelines, and cooling water devices connected with the desuperheating pipelines are arranged in the third switch valve groups; The first regulating valve station comprises two first gate valves arranged in series, a first pneumatic regulating valve is arranged between the two first gate valves, and a first check valve is further arranged between the first regulating valve station and the start-up steam transportation pipeline.

2. The starting steam sharing system of a new ultra-supercritical unit and an old subcritical unit according to claim 1, characterized in that, A second regulating valve station is further arranged on the reheated cold section steam supply pipeline, and the second regulating valve station is located between the branch pipeline and the second auxiliary steam headers.

3. The starting steam sharing system of a new ultra-supercritical unit and an old subcritical unit according to claim 2, characterized in that, The second regulating valve station comprises an electric gate valve, a second pneumatic regulating valve and a second check valve arranged in sequence, the electric gate valve is arranged close to an outlet end of the reheated cold section steam, and the second check valve is arranged close to the second auxiliary steam header.

4. The starting steam sharing system of a new ultra-supercritical unit and an old subcritical unit according to claim 1, characterized in that, The first switch valve groups and the second switch valve groups each comprise a third check valve and a second gate valve arranged in series.

5. The starting steam sharing system of a new ultra-supercritical unit and an old subcritical unit according to claim 1, characterized in that, The third switch valve groups comprise two third gate valves arranged in series, the cooling water devices are connected between the two third gate valves, and a fourth check valve is further arranged between the third switch valve groups and the start-up steam transportation pipeline.

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