Turbine system and power generation system including same

Abstract

The utility model provides a steam turbine system and a power generation system comprising the steam turbine system. The steam turbine system comprises a waste heat boiler, a heat exchanger of the waste heat boiler is communicated with a steam turbine set; the high-pressure cylinder is communicated with a first steam outlet end of the waste heat boiler, so that high-pressure steam output by the waste heat boiler expands to do work in the high-pressure cylinder; the low-pressure cylinder communicates with the second steam outlet end of the waste heat boiler and the high-pressure cylinder, so that first low-pressure steam output by the waste heat boiler and second low-pressure steam output by the high-pressure cylinder expand to do work in the low-pressure cylinder; wherein the waste heat boiler communicates with the low-pressure cylinder through a low-pressure pipeline, at least two steam inlets communicating with the waste heat boiler are formed in the low-pressure cylinder in the axial direction at intervals, and the low-pressure pipeline is constructed to selectively open one of the multiple steam inlets according to the pressure of second low-pressure steam output by the high-pressure cylinder; the pressure difference value between the first low-pressure steam and the steam inlet in the open state is within the preset pressure difference range.

Description

Technical Field

[0001] At least one embodiment of the present utility model relates to the technical field of steam turbine systems, and in particular to a steam turbine system and a power generation system including the steam turbine system. Background Art

[0002] In existing gas-steam combined cycle power generation systems, a typical "two-on-one" configuration consists of two gas turbines and a steam turbine system. Each gas turbine and its corresponding waste heat boiler form a gas turbine unit, and the two gas turbine units jointly drive a steam turbine system. The gas turbines in this "two-on-one" unit have high exhaust flow and high exhaust temperature. The waste heat boiler typically uses a dual-pressure steam-water system to improve heat exchange efficiency. The high-pressure steam and low-pressure steam generated by the waste heat boiler enter the high-pressure and low-pressure cylinders of the steam turbine system, respectively, to expand and perform work, thereby achieving high cycle thermal efficiency.

[0003] When a "two-on-one" unit transitions to "one-on-one" operation, with one gas turbine unit shut down and the other operating at full load, the steam parameters provided by the waste heat boiler remain unchanged at their rated values. However, the steam flow rate is reduced by half, and the turbine system is reduced to 50% load. This causes the steam pressure at the steam inlet from the high-pressure cylinder to the low-pressure cylinder to drop to approximately half of that at full load due to the reduced load. At this point, in order to ensure that the pressure of the low-pressure steam at the steam inlet from the waste heat boiler to the low-pressure cylinder matches that of the steam at the steam inlet from the high-pressure cylinder, the low-pressure steam must be throttled and reduced in pressure before it can be fed into the low-pressure cylinder of the steam turbine system, resulting in energy loss. Utility Model Content

[0004] In view of this, the utility model provides a steam turbine system, which reduces energy loss during the process in which low-pressure steam output by a waste heat boiler flows into a low-pressure cylinder when the steam turbine system is underloaded.

[0005] According to an embodiment of the present invention, a steam turbine system is provided, comprising: a waste heat boiler, a heat exchanger of which is connected to a steam turbine unit; a high-pressure cylinder, connected to a first steam outlet of the waste heat boiler, so that the high-pressure steam output by the waste heat boiler expands inside the high-pressure cylinder to perform work; and a low-pressure cylinder, connected to a second steam outlet of the waste heat boiler and the high-pressure cylinder, respectively, so that the first low-pressure steam output by the waste heat boiler and the second low-pressure steam output by the high-pressure cylinder expand inside the low-pressure cylinder to perform work; wherein the waste heat boiler is connected to the low-pressure cylinder through a low-pressure pipeline, and at least two steam inlets connected to the waste heat boiler are provided on the low-pressure cylinder at intervals in the axial direction, and the low-pressure pipeline is configured to select one of the multiple steam inlets to open according to the pressure of the second low-pressure steam output by the high-pressure cylinder, so that the pressure difference between the first low-pressure steam and the steam inlet in the open state is within a preset pressure difference range.

[0006] According to an embodiment of the present invention, a plurality of blade stages are arranged in sequence from upstream to downstream in the axial direction inside the low-pressure cylinder, and at least one blade stage is spaced between two adjacent steam inlets; wherein, when the steam turbine unit is operating at full load, the first low-pressure steam flows into the low-pressure cylinder through the steam inlet at the downstream; when the steam turbine unit is operating at underload, the first low-pressure steam flows into the low-pressure cylinder through the steam inlet at the upstream.

[0007] According to an embodiment of the present invention, the low-pressure pipeline includes a main steam circuit and at least two branch steam circuits, and each branch steam circuit is connected to one of the steam inlets.

[0008] According to an embodiment of the present invention, the preset pressure difference range is 0.5-1.0ata.

[0009] According to an embodiment of the present invention, a low-pressure steam inlet valve is provided on the main steam circuit to control the on-off of the main steam circuit; a low-pressure regulating valve is provided on each branch steam circuit to control the opening and closing of the branch steam circuit and adjust the flow rate of the first low-pressure steam in the branch steam circuit.

[0010] According to an embodiment of the present invention, the high-pressure cylinder and the low-pressure cylinder are connected through a connecting pipeline.

[0011] According to an embodiment of the present invention, the high-pressure cylinder and the low-pressure cylinder form a mutually connected whole.

[0012] According to an embodiment of the present invention, the waste heat boiler is connected to the high-pressure cylinder via a high-pressure pipeline, and a high-pressure steam inlet valve and a high-pressure regulating valve are provided on the high-pressure pipeline.

[0013] According to an embodiment of the present invention, the turbine system further includes an exhaust cold end, which is communicated with the low-pressure cylinder and is suitable for receiving circulating exhaust steam.

[0014] According to an embodiment of the present invention, a power generation system is provided, comprising: a steam turbine unit including at least two gas turbines; the steam turbine system described in the above embodiment, wherein the working steam of the steam turbine system is provided by a waste heat boiler connected to the steam turbine unit; and a generator connected to the steam turbine system, which, under the action of the steam turbine system, converts the kinetic energy of the steam turbine unit into electrical energy of the generator.

[0015] According to the steam turbine system of the above-mentioned embodiment of the present invention, at least two steam inlets connected to the waste heat boiler are arranged at intervals in the axial direction on the low-pressure cylinder, and the low-pressure pipeline is constructed to select one of the multiple steam inlets to open according to the pressure of the second low-pressure steam output by the high-pressure cylinder, so that the pressure difference between the first low-pressure steam and the steam inlet in the open state is within a preset pressure difference range, thereby reducing energy loss in the process of the first low-pressure steam flowing into the low-pressure cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the principle of a first embodiment of a generator system according to an embodiment of the present utility model; and

[0017] Figure 2 It is a schematic diagram of the principle of the second embodiment of the generator system of the embodiment of the present utility model.

[0018] In the picture:

[0019] 1-waste heat boiler; 11-second steam outlet; 12-first steam outlet;

[0020] 2- High-pressure cylinder;

[0021] 3- low-pressure cylinder; 31- steam inlet; 32- blade stage;

[0022] 4 low-pressure pipelines;

[0023] 41-main steam line; 411-low-pressure steam inlet valve;

[0024] 42-branch steam line; 421-low pressure regulating valve;

[0025] 43-pressure measuring instrument;

[0026] 5-Connect the pipeline;

[0027] 6-high-pressure pipeline; 61-high-pressure steam inlet valve; 62-high-pressure regulating valve;

[0028] 7-exhaust cold end;

[0029] 8-Generator. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0031] According to the inventive concept of one aspect of the utility model, a steam turbine system is provided, comprising: a waste heat boiler, a heat exchanger of the waste heat boiler is connected to the steam turbine unit; a high-pressure cylinder, connected to a first steam outlet end of the waste heat boiler, so that the high-pressure steam output by the waste heat boiler expands inside the high-pressure cylinder to perform work; and a low-pressure cylinder, connected to a second steam outlet end of the waste heat boiler and the high-pressure cylinder, respectively, so that the first low-pressure steam output by the waste heat boiler and the second low-pressure steam output by the high-pressure cylinder expand inside the low-pressure cylinder to perform work; wherein the waste heat boiler and the low-pressure cylinder are connected through a low-pressure pipeline, and at least two steam inlets connected to the waste heat boiler are arranged at intervals in the axial direction on the low-pressure cylinder, and the low-pressure pipeline is configured to select one of the multiple steam inlets to open according to the pressure of the second low-pressure steam output by the high-pressure cylinder, so that the pressure difference between the first low-pressure steam and the steam inlet in the open state is within a preset pressure difference range.

[0032] Figure 1 1 is a schematic diagram of the principle of a first embodiment of a generator system according to an embodiment of the present utility model; Figure 2 It is a schematic diagram of the principle of the second embodiment of the generator system of the embodiment of the present utility model.

[0033] According to the exemplary embodiment of the present invention, please refer to Figure 1-Figure 2 A steam turbine system is provided, comprising a waste heat boiler 1, a high-pressure cylinder 2, and a low-pressure cylinder 3. The heat exchanger of the waste heat boiler 1 is connected to the steam turbine unit. The high-pressure cylinder 2 is connected to the first steam outlet 12 of the waste heat boiler 1, so that the high-pressure steam output by the waste heat boiler 1 expands and produces work within the high-pressure cylinder 2. The low-pressure cylinder 3 is connected to the second steam outlet 11 of the waste heat boiler 1 and the high-pressure cylinder 2, respectively, so that the first low-pressure steam output by the waste heat boiler 1 and the second low-pressure steam output by the high-pressure cylinder 2 expand and produce work within the low-pressure cylinder 3. The waste heat boiler 1 and the low-pressure cylinder 3 are connected via a low-pressure pipeline 4. The low-pressure cylinder 3 is provided with at least two steam inlets 31 spaced apart in the axial direction and connected to the waste heat boiler 1. The low-pressure pipeline 4 is configured to selectively open one of the multiple steam inlets 31 based on the pressure of the second low-pressure steam output by the high-pressure cylinder 2, so that the pressure difference between the first low-pressure steam and the open steam inlet 31 is within a preset pressure difference range.

[0034] In this embodiment, at least two steam inlets 31 connected to the waste heat boiler 1 are arranged at intervals along the axial direction on the low-pressure cylinder 3, and the low-pressure pipeline 4 is constructed to select one of the multiple steam inlets 31 to open according to the pressure of the second low-pressure steam output by the high-pressure cylinder 2, so that the pressure difference between the first low-pressure steam and the steam inlet 31 in the open state is within a preset pressure difference range, thereby avoiding the need to throttle and reduce the pressure of the first low-pressure steam based on the pressure matching of the first low-pressure steam and the second low-pressure steam, thereby reducing the energy loss in the process of the first low-pressure steam flowing into the low-pressure cylinder 3.

[0035] It should be noted that in this embodiment, the high-pressure steam output by the waste heat boiler 1 has high pressure, high temperature, and high flow rate. It flows sequentially through the high-pressure cylinder 2 and low-pressure cylinder 3 of the steam turbine system, expanding and producing work within these cylinders. The low-pressure steam output by the waste heat boiler 1 has low pressure, low temperature, and low flow rate, expanding and producing work only within the low-pressure cylinder 3 of the steam turbine system. At the steam inlet 31 of the low-pressure cylinder 3, the pressures of the first and second low-pressure steam must be strictly matched. The pressure of the first low-pressure steam should be slightly higher than the pressure of the second low-pressure steam flowing to the steam inlet 31 of the low-pressure cylinder 3. If the pressure of the first low-pressure steam is too low, it cannot be replenished. If the pressure of the first low-pressure steam is too high, the flow upstream of the steam inlet 31 will be degraded. The temperature difference between the first and second low-pressure steam should be within a specified limit, otherwise it will cause significant local thermal stress. The specified limit is preferably 40°C.

[0036] Furthermore, through the above-mentioned configuration, the pressure and temperature parameters of the first low-pressure steam and the second low-pressure steam are more closely matched, thereby reducing the local thermal stress caused by the temperature difference.

[0037] In some exemplary embodiments, referring to Figure 1-Figure 2 The low-pressure cylinder 3 is provided with multiple blade stages 32 in the axial direction from upstream to downstream, with at least one blade stage 32 between two adjacent steam inlets 31. When the steam turbine is operating at full load, the first low-pressure steam flows into the low-pressure cylinder 3 through the downstream steam inlet 31. When the steam turbine is operating at underload, the first low-pressure steam flows into the low-pressure cylinder 3 through the upstream steam inlet 31.

[0038] This arrangement allows the first low-pressure steam to expand and perform work within a greater number of blade stages 32 within the low-pressure cylinder 3, thereby increasing output power. This avoids the need to throttle and reduce the pressure of the first low-pressure steam to match the pressures of the first and second low-pressure steam, which results in energy loss. This, in turn, improves the cycle thermal efficiency of the steam turbine system to a certain extent.

[0039] It should be noted that, in this embodiment, the direction from upstream to downstream is Figure 1 The direction indicated by arrow A.

[0040] In some exemplary embodiments, referring to Figure 1-Figure 2 The low-pressure pipeline 4 includes a main steam circuit 41 and at least two branch steam circuits 42 , and each branch steam circuit 42 is connected to a steam inlet 31 .

[0041] Through the above-mentioned setting method, according to the different operating conditions of the steam turbine unit, the first low-pressure steam flows into the low-pressure cylinder 3 through different steam inlets 31 through different branch steam paths 42 to match the first low-pressure steam with the second low-pressure steam under different operating conditions of the steam turbine unit.

[0042] In some exemplary embodiments, the preset pressure difference range is 0.5-1.0 ata.

[0043] In some exemplary embodiments, referring to Figure 1-Figure 2 The main steam circuit 41 is provided with a low-pressure steam inlet valve 411 to control the on-off of the main steam circuit 41. Each branch steam circuit 42 is provided with a low-pressure regulating valve 421 to control the opening and closing of the branch steam circuit 42 and adjust the flow rate of the first low-pressure steam in the branch steam circuit 42.

[0044] It should be noted that, in this embodiment, a pressure measuring gauge 43 is provided on the main steam circuit 41 and each branch steam circuit 42 to detect the pressure value of the first low-pressure steam flowing through the main steam circuit 41 and each branch steam circuit 42 respectively.

[0045] In some exemplary embodiments, referring to Figure 1 The high-pressure cylinder 2 and the low-pressure cylinder 3 are connected through a connecting pipe 5.

[0046] In some exemplary embodiments, referring to Figure 2 The high-pressure cylinder 2 and the low-pressure cylinder 3 form a mutually connected whole.

[0047] In some exemplary embodiments, referring to Figure 1-Figure 2 The waste heat boiler 1 is connected to the high-pressure cylinder 2 through a high-pressure pipeline 6, and a high-pressure steam inlet valve 61 and a high-pressure regulating valve 62 are provided on the high-pressure pipeline 6.

[0048] It should be noted that, in this embodiment, pressure measuring gauges 43 are respectively provided at the steam outlet end of the high-pressure pipeline 6 and the high-pressure cylinder 2 to respectively detect the pressure values ​​of the high-pressure steam flowing through the high-pressure pipeline 6 and the second low-pressure steam output by the high-pressure cylinder 2.

[0049] In some exemplary embodiments, referring to Figure 1-Figure 2 The turbine system also includes an exhaust cold end 7, which is connected to the low-pressure cylinder 3 and is suitable for receiving circulating exhaust steam.

[0050] It should be noted that in this embodiment, when the steam turbine unit is operating at full load, for example, when both gas turbines are operating at full load, the steam turbine system operates at 100% load. At the downstream steam inlet 31, the second low-pressure steam output from the high-pressure cylinder 2 matches the pressure and temperature of the first low-pressure steam output from the waste heat boiler 1. At this point, the upstream steam inlet 31 is closed, and all of the first low-pressure steam output from the waste heat boiler 1 enters the low-pressure cylinder 3 through the branch steam path 42 connected to the downstream steam inlet 31, where it expands and performs work.

[0051] When the steam turbine unit is operating at underload, for example, with one gas turbine shut down and the other operating at full load, the steam turbine system operates at 50% load. At the upstream steam inlet 31, the pressure and temperature of the second low-pressure steam output from the high-pressure cylinder 2 match those of the first low-pressure steam output from the waste heat boiler 1. At this point, the downstream steam inlet 31 is closed, and all of the first low-pressure steam output from the waste heat boiler 1 enters the low-pressure cylinder 3 through the branch steam path 42 connected to the upstream steam inlet 31, expanding and performing work.

[0052] According to the exemplary embodiment of the present invention, please refer to Figure 1-Figure 2 , provides a power generation system comprising a steam turbine unit, the steam turbine system described in the above embodiment, and a generator 8. The steam turbine unit comprises at least two gas turbines. The working steam for the steam turbine system is provided by a waste heat boiler 1 connected to the steam turbine unit. The generator 8 is connected to the steam turbine system and, under the action of the steam turbine system, converts the kinetic energy of the steam turbine unit into electrical energy for the generator 8.

[0053] It should be noted that, in this embodiment, the generator 8 is connected to the rotor of the high-pressure cylinder 2 and the rotor of the low-pressure cylinder 3 of the steam turbine system through a coupling to achieve conversion of mechanical energy into electrical energy.

[0054] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A steam turbine system, characterized in that: include: A waste heat boiler (1), wherein a heat exchanger of the waste heat boiler (1) is connected to a steam turbine unit; A high-pressure cylinder (2) is connected to the first steam outlet (12) of the waste heat boiler (1), so that the high-pressure steam output by the waste heat boiler (1) expands inside the high-pressure cylinder (2) to perform work; and The low-pressure cylinder (3) is respectively connected to the second steam outlet (11) of the waste heat boiler (1) and the high-pressure cylinder (2), so that the first low-pressure steam output by the waste heat boiler (1) and the second low-pressure steam output by the high-pressure cylinder (2) expand inside the low-pressure cylinder (3) to perform work; The waste heat boiler (1) is connected to the low-pressure cylinder (3) via a low-pressure pipeline (4); at least two steam inlets (31) connected to the waste heat boiler (1) are arranged at intervals along the axial direction on the low-pressure cylinder (3); and the low-pressure pipeline (4) is configured to select one of the multiple steam inlets (31) to be opened according to the pressure of the second low-pressure steam output by the high-pressure cylinder (2), so that the pressure difference between the first low-pressure steam and the steam inlet (31) in the open state is within a preset pressure difference range.

2. The steam turbine system according to claim 1, characterized in that A plurality of blade stages (32) are sequentially arranged inside the low-pressure cylinder (3) along the axial direction from upstream to downstream, and at least one blade stage (32) is spaced between two adjacent steam inlets (31); Wherein, when the steam turbine unit is operating at full load, the first low-pressure steam flows into the low-pressure cylinder (3) through the steam inlet (31) located downstream; when the steam turbine unit is operating at underload, the first low-pressure steam flows into the low-pressure cylinder (3) through the steam inlet (31) located upstream.

3. The steam turbine system according to claim 2, characterized in that The low-pressure pipeline (4) comprises a main steam circuit (41) and at least two branch steam circuits (42), and each branch steam circuit (42) is in communication with one of the steam inlets (31).

4. The steam turbine system according to any one of claims 1 to 3, characterized in that: The preset pressure difference range is 0.5-1.0ata.

5. The steam turbine system according to claim 3, characterized in that The main steam circuit (41) is provided with a low-pressure steam inlet valve (411) to control the on-off of the main steam circuit (41); Each branch steam circuit (42) is provided with a low-pressure regulating valve (421) to control the opening and closing of the branch steam circuit (42) and to adjust the flow rate of the first low-pressure steam in the branch steam circuit (42).

6. The steam turbine system according to claim 1, characterized in that The high-pressure cylinder (2) and the low-pressure cylinder (3) are connected via a connecting pipe (5).

7. The steam turbine system according to claim 1, characterized in that The high-pressure cylinder (2) and the low-pressure cylinder (3) form a mutually connected whole.

8. The steam turbine system according to claim 1, characterized in that The waste heat boiler (1) is connected to the high-pressure cylinder (2) via a high-pressure pipeline (6), and a high-pressure steam inlet valve (61) and a high-pressure regulating valve (62) are provided on the high-pressure pipeline (6).

9. The steam turbine system according to claim 1, characterized in that The steam turbine system further comprises an exhaust cold end (7), which is in communication with the low-pressure cylinder (3) and is suitable for receiving circulating exhaust steam.

10. A power generation system, characterized in that: include: a steam turbine unit comprising at least two gas turbines; The steam turbine system according to any one of claims 1 to 9, wherein the working steam of the steam turbine system is provided by a waste heat boiler (1) connected to the steam turbine unit; as well as A generator (8) is connected to the steam turbine system and, under the action of the steam turbine system, converts the kinetic energy of the steam turbine set into electrical energy of the generator (8).

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