Industrial steam supply combined heat and power generation system with coal-fired unit coupled with steam ejector

Abstract

The utility model discloses an industrial steam supply combined heat and power generation system of a coal-fired unit coupled steam ejector, and belongs to the technical field of energy conservation and consumption reduction of coal-fired units. According to the system, three sources are arranged on ejection steam of a steam ejector, namely steam from a boiler, steam from an intermediate pressure cylinder and steam from a small back pressure machine, meanwhile, valves are arranged on corresponding branches, and through the arrangement of the steam sources and the corresponding valves, under different unit loads, the steam can be supplied to the steam ejector, so that the energy consumption of the steam ejector is reduced, and the energy consumption of the steam ejector is reduced. Different gas sources can be arranged for the steam ejector, the stable industrial steam supply requirement can be met within the wide load range, and the operation flexibility of a unit is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of energy conservation and consumption reduction of coal-fired units, and relates to an industrial steam supply thermoelectric co-generation system with a coal-fired unit coupled with a steam ejector. Background Art

[0002] With the increase in the installed capacity of new energy and its continuous increase in the proportion of the power market, traditional coal-fired power units are transforming into basic energy sources and peak-shaving energy sources. With the continuous increase in the peak-shaving tasks of coal-fired power units, there is thermoelectric coupling in some heat supply and steam supply units.

[0003] Facing the large-scale grid connection of new energy and the randomness and volatility of power generation characteristics, traditional coal-fired power units need to gradually transform from the main power source to basic energy sources and peak-shaving energy sources. As a basic energy source, coal power still plays an irreplaceable role in the power system in terms of its stable supply ability; while as a peak-shaving energy source, coal-fired power units need to frequently adjust their output to balance the instability of new energy power generation and ensure the safe and stable operation of the power system.

[0004] With the increase in the peak-shaving tasks of coal-fired power units, some heat supply and steam supply units are facing the complex problem of thermoelectric coupling. Thermoelectric coupling refers to the close connection between power production and heat supply, that is, the same set of equipment provides heat energy for users while generating electricity. During the peak-shaving process, coal-fired power units need to adjust their power generation according to the grid demand, which often leads to fluctuations or even interruptions in heat supply, affecting the heat demand of users. At the same time, the change of fuel type and the adjustment of unit operation status during the peak-shaving process may also have an adverse impact on the heat supply quality.

[0005] In some peak-shaving units, by introducing a steam ejector, superheated steam can be used to eject the exhaust steam of the steam turbine, and the mixed steam can be used as the heat source of the high-pressure heater to heat the return water of the heat network, which can significantly increase the heating supply of the unit. However, after introducing the steam ejector, it is still difficult to fully meet the external steam supply demand of the coal-fired unit at different loads. Summary of the Utility Model

[0006] The purpose of the utility model is to overcome the above-mentioned shortcomings of the prior art and provide an industrial steam supply thermoelectric co-generation system with a coal-fired unit coupled with a steam ejector, so as to solve the problem that it is still difficult to fully realize the cascade utilization of heat in the coal-fired unit after introducing the steam ejector in the prior art.

[0007] To achieve the above purpose, the utility model adopts the following technical solutions:

[0008] An industrial steam supply thermoelectric co-generation system with a coal-fired unit coupled with a steam ejector, including a boiler, a high-pressure steam turbine, an intermediate-pressure steam turbine, and a low-pressure steam turbine connected in sequence through steam pipelines, and further including a steam ejector;

[0009] A first branch is provided on the steam connection pipeline between the boiler and the medium-pressure steam turbine, and the first branch is communicated with the entrained steam inlet of the steam ejector; a second branch is provided on the steam connection pipeline between the medium-pressure steam turbine and the low-pressure steam turbine, and the second branch is communicated with the entrained steam inlet of the steam ejector;

[0010] The exhaust steam outlet of the low-pressure steam turbine is communicated with the working steam inlet of the steam ejector;

[0011] A third branch is provided on the first branch, the third branch is connected with the steam inlet of the small back-pressure turbine, and the steam outlet of the small back-pressure turbine is communicated with the third branch;

[0012] A first control valve is provided on the first branch, and the first control valve is between the inlet of the third branch and the steam outlet pipeline of the small back-pressure turbine; a fifth control valve is provided on the third branch, and a third control valve is provided on the second branch.

[0013] Preferably, a second control valve is provided on the first branch before the third branch.

[0014] Preferably, a fourth control valve is provided on the connection pipeline between the exhaust steam outlet of the low-pressure steam turbine and the working steam inlet of the steam ejector.

[0015] Preferably, a sixth control valve is provided on the steam outlet pipeline of the small back-pressure turbine.

[0016] Preferably, the high-pressure steam turbine, the medium-pressure steam turbine and the low-pressure steam turbine jointly drive a power output shaft, and the power output shaft is connected with a generator.

[0017] Preferably, the steam outlet of the low-pressure steam turbine is connected with a condenser.

[0018] Preferably, the power output shaft of the small back-pressure turbine is connected with a back-pressure turbine generator;

[0019] Preferably, the boiler is divided into a superheat section and a reheating section.

[0020] Preferably, the steam outlet of the superheat section is communicated with the steam inlet of the high-pressure steam turbine, and the steam outlet of the high-pressure steam turbine is communicated with the steam inlet of the reheating section.

[0021] Preferably, the steam outlet of the reheating section is communicated with the steam inlet of the medium-pressure steam turbine.

[0022] Compared with the prior art, the utility model has the following beneficial effects:

[0023] The utility model discloses an industrial steam supply thermoelectric cogeneration system coupling a steam ejector in a coal-fired unit. In this system, three sources of steam are set for the entrained steam of the steam ejector, namely steam from the boiler, steam from the intermediate-pressure cylinder, and steam from the small back-pressure turbine. At the same time, respective valves are set on the corresponding branches. Through the setting of the steam sources and the corresponding valves, different gas sources can be set for the steam ejector under different unit loads, and the stable industrial steam supply demand can be met within a wide load range, improving the operation flexibility of the unit.

[0024] Furthermore, by setting the second control valve, the gas source for the steam ejector or the small back-pressure turbine can be completely cut off, facilitating the supply of the exhaust steam of the intermediate-pressure cylinder to the steam ejector.

[0025] Furthermore, by setting the fourth control valve, the amount of steam supplied to the steam ejector can be adjusted.

[0026] Furthermore, by setting the sixth control valve, in cooperation with the fifth control valve, the steam input and output of the small back-pressure turbine can be cut off.

[0027] Furthermore, a condenser is provided at the steam outlet of the low-pressure steam turbine for cooling the exhaust steam of the low-pressure steam turbine.

[0028] Furthermore, the power output shaft of the small back-pressure turbine is connected with a back-pressure turbine generator, and through the back-pressure turbine generator, the steam energy can be further converted into electric energy, making full use of the low-grade energy output from the boiler. Description of the Drawings

[0029] Figure 1 It is a structure diagram of an industrial steam supply thermoelectric cogeneration system coupling a steam ejector in a coal-fired unit.

[0030] In the figure: 1. Boiler; 101. Superheat section; 102. Reheat section; 2. High-pressure steam turbine; 3. Intermediate-pressure steam turbine; 4. Low-pressure steam turbine; 5. Generator; 6. Condenser; 7. Small back-pressure turbine; 8. Back-pressure turbine generator; 9. Steam ejector; 10. First branch; 11. Second branch; 13. Third branch; 14. First control valve; 15. Second control valve; 16. Third control valve; 17. Fourth control valve; 18. Fifth control valve; 19. Sixth control valve. Detailed Embodiment

[0031] The following further describes the present utility model in detail with reference to the drawings:

[0032] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation to the present utility model.

[0033] Embodiment 1

[0034] The present utility model discloses an industrial steam supply thermoelectric cogeneration system coupling a steam ejector with a coal-fired unit, which includes a superheated section 101 of a boiler 1, a high-pressure steam turbine 2, a reheating section 102 of the boiler 1, an intermediate-pressure steam turbine 3, a low-pressure steam turbine 4, and a condenser 6 that are connected in sequence.

[0035] It further includes a generator 5, a small back-pressure turbine 7, a back-pressure turbine generator 8, a steam ejector 9, a first control valve 14, a second control valve 15, a third control valve 16, a fourth control valve 17, a fifth control valve 18, and a sixth control valve 19.

[0036] The high-pressure steam turbine 2, the intermediate-pressure steam turbine 3, and the low-pressure steam turbine 4 drive the main steam turbine generator 5 to rotate and generate electric energy.

[0037] Part of the exhaust steam of the low-pressure steam turbine 4 enters the steam ejector 9, and part enters the condenser 6 to be cooled;

[0038] The steam source for the steam ejector 9 can be switched among the steam of the superheated section 101 of the boiler 1, the exhaust steam of the small back-pressure turbine 7, and the exhaust steam of the intermediate-pressure steam turbine 3. The exhaust steam of the low-pressure steam turbine 4 serves as the steam source to be entrained by the steam ejector 9, and the steam at the outlet of the steam ejector 9 serves as industrial steam supply.

[0039] The inlet of the superheated section 101 of the boiler 1 is boiler feed water; the inlet of the high-pressure steam turbine 2 is connected to the outlet of the superheated section 101 of the boiler 1, and the outlet of the high-pressure steam turbine 2 is connected to the inlet of the reheating section 102 of the boiler 1; on the connecting pipeline between the outlet of the intermediate-pressure steam turbine 3 and the reheating section 102 of the boiler 1, a first branch 10 is provided. Along the steam flow direction on the first branch 10, a second control valve 15 and a first control valve 14 are arranged in sequence. The terminal of the first branch 10 flows to the entrained steam inlet of the steam ejector 9. The inlet of the intermediate-pressure steam turbine 3 is connected to the outlet of the reheating section 102 of the boiler 1 and the inlet of the second control valve 15.

[0040] On the steam connecting pipeline between the intermediate-pressure steam turbine 3 and the low-pressure steam turbine 4, a second branch 11 is provided. The second branch 11 is connected to the entrained steam inlet of the steam ejector 9; a third control valve 16 is provided on the second branch 11. The outlet of the intermediate-pressure steam turbine 3 is connected to the inlet of the third control valve 16 and the inlet of the low-pressure steam turbine 4; the outlet of the low-pressure steam turbine 4 is connected to the hot-side working medium inlet of the condenser 6 and the inlet of the fourth control valve 17.

[0041] A third branch 13 is connected in parallel with the first control valve 14. A fifth control valve 18, a small back-pressure turbine 7 and a sixth control valve 19 are sequentially arranged on the third branch 13.

[0042] The steam inlet of the steam ejector 9 is connected to the outlet of the first control valve 14, the outlet of the third control valve 16 and the outlet of the sixth control valve 19. The steam inlet to be entrained of the steam ejector 9 is connected to the outlet of the fourth control valve 17.

[0043] The inlet of the small back-pressure turbine 7 is connected to the outlet of the fifth control valve 18. The outlet of the small back-pressure turbine 7 is connected to the outlet of the sixth control valve 19. The inlet of the fifth control valve 18 is connected to the outlet of the second control valve 15 and the inlet of the first control valve 14.

[0044] It should be noted that the above valves can be throttle valves or speed control valves, etc., which can adjust the steam flow rate.

[0045] Embodiment 2

[0046] Through the above device, the working process of the unit is as follows:

[0047] When the unit load is above 70%, the first control valve 14, the second control valve 15, the fifth control valve 18 and the sixth control valve 19 are closed, the third control valve 16 and the fourth control valve 17 are opened, and a part of the exhaust steam of the intermediate-pressure steam turbine 3 is shunted as the steam source for the steam ejector 9 to entrain. The entrained steam source is high-parameter steam, and the steam source to be entrained is low-parameter steam.

[0048] When the unit load is between 50% and 70%, the first control valve 14 and the third control valve 16 are closed, the second control valve 15, the fourth control valve 17, the fifth control valve 18 and the sixth control valve 19 are opened, and the exhaust steam of the small back-pressure turbine 7 is used as the steam source for the steam ejector 9 to entrain.

[0049] When the unit load is below 50%, the third control valve 16, the fifth control valve 18 and the sixth control valve 19 are closed, the first control valve 14, the second control valve 15 and the fourth control valve 17 are opened, and a part of the superheated section 101 of the boiler 1 is shunted as the steam source for the steam ejector 9 to entrain.

[0050] Through the adjustment strategy of multiple control valves of the present utility model, the pressure of the steam source entrained by the steam ejector is relatively stable, and the unit can meet the external industrial steam supply requirements under different electric load conditions, improving the operation flexibility of the unit.

[0051] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise stated, the meaning of "a plurality" is two or more. In the description of the present utility model, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may also include the first and second features not being in direct contact but being in contact through additional features therebetween.

[0052] In the description of the present utility model, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature.

[0053] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0054] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0055] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

[0056] The above description is only for the preferred embodiments of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector, characterized in that: It comprises a boiler (1), a high-pressure steam turbine (2), a medium-pressure steam turbine (3) and a low-pressure steam turbine (4) which are connected in sequence via a steam pipeline, and also comprises a steam ejector (9); A first branch (10) is provided on the steam connection pipeline between the boiler (1) and the medium-pressure steam turbine (3), and the first branch (10) is in communication with an ejection steam inlet of a steam ejector (9); a second branch (11) is provided on the steam connection pipeline between the medium-pressure steam turbine (3) and the low-pressure steam turbine (4), and the second branch (11) is in communication with an ejection steam inlet of the steam ejector (9); The exhaust steam outlet of the low-pressure steam turbine (4) is in communication with the working steam inlet of the steam ejector (9); A third branch (13) is provided on the first branch (10), the third branch (13) is connected to the steam inlet of the small back pressure machine (7), and the steam outlet of the small back pressure machine (7) is in communication with the third branch (13); The first branch (10) is provided with a first control valve (14), and the first control valve (14) is between the inlet of the third branch (13) and the steam outlet pipeline of the small back pressure machine (7); the third branch (13) is provided with a fifth control valve (18), and the second branch (11) is provided with a third control valve (16).

2. The industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector according to claim 1, characterized in that: The first branch (10) is provided with a second control valve (15) before the third branch (13).

3. The industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector according to claim 1, characterized in that: A fourth control valve (17) is provided on the connecting pipeline between the exhaust steam outlet of the low-pressure steam turbine (4) and the working steam inlet of the steam ejector (9).

4. The industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector according to claim 1, characterized in that: A sixth control valve (19) is provided on the steam outlet pipeline of the small back pressure machine (7).

5. The industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector according to claim 1, characterized in that: The high-pressure steam turbine (2), the medium-pressure steam turbine (3) and the low-pressure steam turbine (4) jointly drive a power output shaft, and the power output shaft is connected to a generator (5).

6. The industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector according to claim 1, characterized in that: The steam outlet of the low-pressure steam turbine (4) is connected to a condenser (6).

7. The industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector according to claim 1, characterized in that: The power output shaft of the small back pressure machine (7) is connected to a back pressure machine generator (8).

8. The industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector according to claim 1, characterized in that: The boiler (1) is divided into a superheating section (101) and a reheating section (102).

9. The industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector according to claim 8, characterized in that: The steam outlet of the superheating section (101) is connected to the steam inlet of the high-pressure steam turbine (2), and the steam outlet of the high-pressure steam turbine (2) is connected to the steam inlet of the reheating section (102).

10. The industrial steam supply heat and power cogeneration system of a coal-fired unit coupled with a steam ejector according to claim 8, characterized in that: The steam outlet of the reheat section (102) is in communication with the steam inlet of the medium-pressure steam turbine (3).

Images