Steam-water circulation system for steam generator

Abstract

The utility model discloses a steam-water circulation system for a steam generator, which belongs to the technical field of nuclear power operation and comprises the steam generator, a steam turbine, a condenser, a starting water supply tank, a deaerator, a sixth valve group, a first valve group, a second valve group, a third valve group, a fourth valve group, a fifth valve group and a sixth valve group. According to the system, thermal load impact on the condenser at the initial stage of starting of the unit can be avoided, meanwhile, water consumption and heat consumption in the starting process are low, and safe operation of the unit can be guaranteed when feed water transmission fluctuates.

Description

Technical Field

[0001] The utility model belongs to the technical field of nuclear power operation and relates to a steam-water circulation system for a steam generator. Background Art

[0002] A direct current steam generator is a steam generator that produces steam in which the working fluid passes through each heating surface once and there is no forced flow of circulation. Compared with a drum-type steam generator, it has the advantages of low noise, compact structure, higher thermal efficiency and less energy loss, and is widely used in nuclear power generation systems. During the startup of a direct current steam generator, the feed water will undergo three phase changes in the evaporator, namely, supercooled water, saturated steam and superheated steam. It has the instability of the vapor-liquid two-phase flow and the complex and changeable operation characteristics of boiling heat transfer. A steam-water separation system is required during the startup process. The currently designed direct current steam generator generally sets the steam-water separator at the outlet of the superheated section of the steam generator heat transfer tube, and the entire startup process is completed by the main feed water operation circuit. There are at least the following disadvantages: First, a large amount of drain and steam are generated in the steam-water separator at the initial start-up of the unit. The discharge of drain and steam into the condenser will cause a heat load shock to the condenser; second, in order to ensure that the feed water temperature at the steam generator inlet meets the unit startup requirements, external steam is required to supply the deaerator to heat the feed water when the main feed water operation loop is started. The water consumption and heat consumption during the startup process are relatively large; third, when the feed water fluctuates during the operation of the unit, the feed water directly enters the superheated section of the steam generator heat transfer tube, which will cause large fluctuations in the main steam temperature, which is not conducive to the safe operation of the unit. Utility Model Content

[0003] The purpose of the utility model is to overcome the shortcomings of the above-mentioned prior art and provide a steam-water circulation system for a steam generator, which can avoid the heat load shock to the condenser in the initial stage of the unit startup. At the same time, the water consumption and heat consumption during the startup process are low, and when the water supply fluctuates, the safe operation of the unit can be guaranteed.

[0004] To achieve the above object, the utility model discloses a steam-water circulation system for a steam generator, comprising the steam generator, a steam-water separator, a steam turbine, a deaerator, a start-up feed water tank and a condenser;

[0005] The secondary side of the steam generator is provided with an evaporation section of the heat transfer tube of the steam generator and an overheating section of the heat transfer tube of the steam generator. The gas outlet of the steam-water separator and the outlet of the overheating section of the heat transfer tube of the steam generator are connected through a pipeline and then divided into two paths, one of which is connected to the inlet of the steam turbine through the third valve group, and the other is connected to the inlet of the condenser and the inlet of the starting feed water tank. The outlet of the deaerator is connected to the inlet of the evaporation section of the heat transfer tube of the steam generator, and the outlet of the starting feed water tank is connected to the inlet of the evaporation section of the heat transfer tube of the steam generator. The outlet of the evaporation section of the heat transfer tube of the steam generator is divided into two paths, one of which is connected to the inlet of the overheating section of the heat transfer tube of the steam generator, and the other is connected to the inlet of the steam-water separator. The water outlet of the steam-water separator is connected to the inlet of the starting feed water tank.

[0006] The outlet of the evaporation section of the heat transfer tube of the steam generator is divided into two paths, one of which is connected to the inlet of the superheating section of the heat transfer tube of the steam generator through the first valve group, and the other is connected to the inlet of the steam-water separator through the second valve group;

[0007] The gas outlet of the steam-water separator passes through the fourth valve group and is connected to the outlet of the superheating section of the heat transfer tube of the steam generator through a pipeline and then divided into two paths, one of which is connected to the inlet of the steam turbine through the third valve group, and the other is connected to the inlet of the fifth valve group;

[0008] The exhaust port of the steam turbine is connected to the inlet of the condenser. The outlet of the fifth valve group is divided into two paths, one of which is connected to the inlet of the condenser, and the other is connected to the inlet of the start-up feed water tank through the sixth valve group. The steam extraction port of the steam turbine is connected to the inlet of the deaerator.

[0009] The outlet of the condenser is divided into two paths after passing through the condensate pump, one of which is connected to the inlet of the start-up feed water tank through the seventh valve group, and the other is connected to the inlet of the deaerator through the eighth valve group.

[0010] The water outlet of the steam-water separator is connected with the inlet of the starting water supply tank through the ninth valve group.

[0011] The outlet of the starting water supply tank is connected to the inlet of the evaporation section of the heat transfer tube of the steam generator through the starting water supply pump and the tenth valve group.

[0012] The steam extraction port of the steam turbine is connected to the inlet of the deaerator through the twelfth valve group.

[0013] The outlet of the deaerator is connected to the inlet of the evaporation section of the heat transfer tube of the steam generator through the main feed water pump and the eleventh valve group.

[0014] Also included is a reactor, which is connected to the primary side of the steam generator.

[0015] The utility model has the following beneficial effects:

[0016] During specific operation of the steam-water circulation system for a steam generator described in the utility model, at the initial start-up stage, the water separated in the steam-water separator is used as the start-up feed water, and the separated steam is used as the heating steam for the start-up feed water tank, thereby greatly reducing the water consumption and heat consumption during the start-up process; in the low-load operation stage of the reactor and the generator, the main steam bypass steam is used as the heating steam for the start-up feed water tank, and the condensate is used as the start-up feed water, thereby avoiding a large amount of main steam bypassed into the condenser during low-load operation, causing a thermal load shock to the condenser, and at the same time, this part of the heat is used to heat the start-up feed water, thereby greatly reducing the external steam supply compared to the original design, and achieving obvious energy-saving effects; after the reactor and the generator reach 30% of the rated load, the start-up feed water circuit is cut off, and the main feed water operation circuit is put into use to complete the unit start-up process, thereby realizing the disturbance-free switching between the start-up feed water circuit and the main feed water operation circuit, thereby improving the safety of the unit start-up process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the utility model.

[0018] Among them, 1 is a reactor, 2 is a steam generator, 2-1 is an evaporation section of a heat transfer tube of a steam generator, 2-2 is an overheating section of a heat transfer tube of a steam generator, 3 is a steam-water separator, 4 is a steam turbine, 5 is a generator, 6 is a condenser, 7 is a starting feed water tank, 8 is a condensate pump, 9 is a deaerator, 10 is a starting feed water pump, 11 is a main feed water pump, 12 is a first valve group, 13 is a second valve group, 14 is a third valve group, 15 is a fourth valve group, 16 is a fifth valve group, 17 is a sixth valve group, 18 is a seventh valve group, 19 is an eighth valve group, 20 is a ninth valve group, 21 is a tenth valve group, 22 is an eleventh valve group, and 23 is a twelfth valve group. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only an embodiment of a part of the utility model, not all embodiments, and is not intended to limit the scope of the disclosure of the utility model. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the utility model.

[0020] The accompanying drawings show schematic diagrams of structures according to the disclosed embodiments of the utility model. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0021] Embodiment 1

[0022] refer to Figure 1 The steam-water circulation system for a steam generator of the utility model comprises a reactor 1, a steam generator 2, an evaporation section 2-1 of a heat transfer tube of a steam generator, an overheating section 2-2 of a heat transfer tube of a steam generator, a steam-water separator 3, a steam turbine 4, a generator 5, a condenser 6, a start-up feed water tank 7, a condensate pump 8, a deaerator 9, a start-up feed water pump 10, a main feed water pump 11, a first valve group 12, a second valve group 13, a third valve group 14, a fourth valve group 15, a fifth valve group 16, a sixth valve group 17, a seventh valve group 18, an eighth valve group 19, a ninth valve group 20, a tenth valve group 21, an eleventh valve group 22 and a twelfth valve group 23;

[0023] The secondary side of the steam generator 2 is provided with a steam generator heat transfer tube evaporation section 2-1 and a steam generator heat transfer tube superheating section 2-2. The reactor 1 is connected to the primary side of the steam generator 2. The gas outlet of the steam-water separator 3 is connected to the outlet of the steam generator heat transfer tube superheating section 2-2 through a pipeline after passing through the fourth valve group 15 and then divided into two paths, one of which is connected to the inlet of the steam turbine 4 through the third valve group 14, and the other is connected to the inlet of the fifth valve group 16. The exhaust port of the steam turbine 4 is connected to the inlet of the condenser 6. The outlet of the condenser 6 is divided into two paths after passing through the condensate pump 8, one of which is connected to the inlet of the start-up feed water tank 7 through the seventh valve group 18, and the other is connected to the inlet of the deaerator 9 through the eighth valve group 19. The outlet of the fifth valve group 16 is divided into two paths, one of which is connected to the inlet of the start-up feed water tank 7 through the seventh valve group 18, and the other is connected to the inlet of the deaerator 9 through the eighth valve group 19. The inlet of the condenser 6 is connected, and the other is connected to the inlet of the starting feed water tank 7 through the sixth valve group 17. The steam extraction port of the turbine 4 is connected to the inlet of the deaerator 9 through the twelfth valve group 23. The outlet of the deaerator 9 is connected to the inlet of the evaporation section 2-1 of the heat transfer tube of the steam generator through the main feed water pump 11 and the eleventh valve group 22. The outlet of the starting feed water tank 7 is connected to the inlet of the evaporation section 2-1 of the heat transfer tube of the steam generator through the starting feed water pump 10 and the tenth valve group 21. The outlet of the evaporation section 2-1 of the heat transfer tube of the steam generator is divided into two routes, one of which is connected to the inlet of the superheating section 2-2 of the heat transfer tube of the steam generator through the first valve group 12, and the other is connected to the inlet of the steam-water separator 3 through the second valve group 13. The water outlet of the steam-water separator 3 is connected to the inlet of the starting feed water tank 7 through the ninth valve group 20.

[0024] Embodiment 2

[0025] refer to Figure 1 , the working process of this embodiment is:

[0026] 1) Fill the start-up feed water tank 7 with feed water, the reactor 1 starts, open the second valve group 13, the fourth valve group 15, the fifth valve group 16, the sixth valve group 17 and the eighth valve group 19, start the feed water pump 10, and transfer the feed water in the start-up feed water tank 7 to the evaporation section 2-1 of the heat transfer tube of the steam generator. The feed water absorbs the heat transferred from the reactor 1 to the primary side of the steam generator 2 in the evaporation section 2-1 of the heat transfer tube of the steam generator, and becomes a steam-water mixture after being heated. Then, the feed water enters the steam generator 2 through the second valve group 13. The steam separated by the steam-water separator 3 is discharged into the starting feed water tank 7 through the tenth valve group 21 for replenishing the starting feed water, and the steam separated by the steam-water separator 3 enters the starting feed water tank 7 through the fourth valve group 15, the fifth valve group 16 and the sixth valve group 17 for heating the feed water in the starting feed water tank 7. The feed water in the starting feed water tank 7 is transported to the evaporation section 2-1 of the steam generator heat transfer tube through the starting feed water pump 10 to continue absorbing heat, thereby completing the startup steam-water cycle of the reactor 1.

[0027] 2) When the reactor has 1 liter power, when the steam-water separator 3 is at a low liquid level, the working medium output from the evaporation section 2-1 of the steam generator heat transfer tube is converted into saturated steam, the first valve group 12, the third valve group 14 and the seventh valve group 18 are opened, the second valve group 13 and the fourth valve group 15 are closed, the steam-water separator 3 is isolated, and the saturated steam output from the evaporation section 2-1 of the steam generator heat transfer tube enters the superheating section 2-2 of the steam generator heat transfer tube through the first valve group 12 to continue to be heated and converted into superheated steam, and then enters the steam turbine 4 through the third valve group 14 to perform work, and The generator 5 is driven to start generating electricity, the exhaust steam of the turbine 4 enters the condenser 6 for condensation, and then is transported to the starting feed water tank 7 through the condensate pump 8 and the seventh valve group 18. Part of the steam output from the superheating section 2-2 of the steam generator heat transfer tube enters the starting feed water tank 7 through the fifth valve group 16 and the sixth valve group 17, and is used to heat the feed water in the starting feed water tank 7. The feed water in the starting feed water tank 7 is transported to the evaporation section 2-1 of the steam generator heat transfer tube through the starting feed water pump 10 to continue absorbing heat, thereby completing the steam-water cycle of the reactor 1 and the generator 5 under low load.

[0028] 3) The reactor 1 continues to increase its power. When the generator 5 is loaded to 30% of the rated load, the twelfth valve group 23 is opened, and the extraction steam of the turbine 4 is discharged into the deaerator 9 through the twelfth valve group 23 to heat the feed water. After the feed water temperature in the deaerator 9 meets the inlet feed water temperature requirement of the steam generator 2, the eleventh valve group 22 is opened, the main feed water pump 11 is started, and the feed water is transported to the steam generator 2 through the main feed water pump 11. The eighth valve group 19 is opened, and the condensate output by the condenser 6 is transported to the deaerator 9 through the condensate pump 8 and the eighth valve group 19. After the feed water flow of the steam generator 2 is stable, the fifth valve group 16, the sixth valve group 17, the eighth valve group 19 and the tenth valve group 21 are closed, the start-up feed water pump 10 is shut down, and the start-up steam-water circuit is isolated.

[0029] The feed water in the deaerator 9 is transported to the evaporation section 2-1 of the heat transfer tube of the steam generator and the superheating section 2-2 of the heat transfer tube of the steam generator through the main feed water pump 11 to continue to absorb heat and be converted into superheated steam, and then enter the steam turbine 4 through the third valve group 14 to do work and drive the generator 5 to start generating electricity. The exhaust steam of the steam turbine 4 enters the condenser 6 to condense, and then is transported to the deaerator 9 through the condensate pump 8 and the eighth valve group 19 to be heated into feed water, and then is transported to the steam generator 2 through the main feed water pump 11 to absorb heat until the reactor 1 is increased to full power, the generator 5 is increased to rated load, and the steam generator 2 is operated at full load, completing the steam-water cycle during the unit startup process.

[0030] It should be noted that the utility model realizes steam-water separation and steam-water circulation at different stages of the unit by dividing the heat transfer tube of the steam generator 2 into an evaporation section and a superheating section, thereby ensuring that the working medium before entering the superheating section 2-2 of the steam generator heat transfer tube is saturated steam, improving the heating efficiency of the working medium in the steam generator 2, and being able to quickly generate a large amount of superheated steam as the power of the reactor 1 increases, thereby improving the startup efficiency of the unit. At the same time, when the feed water fluctuates during operation of the unit, the feed water first enters the steam-water separator 3 to be separated, and will not directly enter the superheating section 2-2 of the steam generator heat transfer tube, thereby improving the stability of the main steam temperature and facilitating the safety of the unit operation.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model is described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the utility model can still be modified or replaced by equivalents, and any modification or equivalent replacement that does not depart from the spirit and scope of the utility model should be included in the scope of protection of the claims of the utility model.

Claims

1. A steam-water circulation system for a steam generator, characterized in that: It comprises the steam generator (2), a steam-water separator (3), a steam turbine (4), a deaerator (9), a starting feed water tank (7) and a condenser (6); The secondary side of the steam generator (2) is provided with a steam generator heat transfer tube evaporation section (2-1) and a steam generator heat transfer tube superheating section (2-2). The gas outlet of the steam-water separator (3) and the outlet of the steam generator heat transfer tube superheating section (2-2) are connected through a pipeline and then divided into two paths, one of which is connected to the inlet of the steam turbine (4) through a third valve group (14), and the other is connected to the inlet of the condenser (6) and the inlet of the start-up feed water tank (7). The deaerator (9 ) is connected to the inlet of the evaporation section (2-1) of the steam generator heat transfer tube, the outlet of the starting water supply tank (7) is connected to the inlet of the evaporation section (2-1) of the steam generator heat transfer tube, the outlet of the evaporation section (2-1) of the steam generator heat transfer tube is divided into two paths, one of which is connected to the inlet of the superheating section (2-2) of the steam generator heat transfer tube, and the other is connected to the inlet of the steam-water separator (3), and the water outlet of the steam-water separator (3) is connected to the inlet of the starting water supply tank (7).

2. The steam-water circulation system for a steam generator according to claim 1, characterized in that: The outlet of the evaporation section (2-1) of the heat transfer tube of the steam generator is divided into two paths, one of which is connected to the inlet of the superheating section (2-2) of the heat transfer tube of the steam generator through the first valve group (12), and the other is connected to the inlet of the steam-water separator (3) through the second valve group (13); The gas outlet of the steam-water separator (3) passes through the fourth valve group (15) and is connected to the outlet of the superheating section (2-2) of the heat transfer tube of the steam generator through a pipeline and then divided into two paths, one of which is connected to the inlet of the steam turbine (4) through the third valve group (14), and the other is connected to the inlet of the fifth valve group (16); The exhaust port of the steam turbine (4) is connected to the inlet of the condenser (6). The outlet of the fifth valve group (16) is divided into two paths, one of which is connected to the inlet of the condenser (6), and the other is connected to the inlet of the start-up feed water tank (7) through the sixth valve group (17). The steam extraction port of the steam turbine (4) is connected to the inlet of the deaerator (9).

3. The steam-water circulation system for a steam generator according to claim 2, characterized in that: The exhaust port of the steam turbine (4) is divided into two paths after passing through the condenser (6).

4. The steam-water circulation system for a steam generator according to claim 2, characterized in that: The outlet of the condenser (6) is divided into two paths after passing through the condensate pump (8), one of which is connected to the inlet of the start-up water supply tank (7) through the seventh valve group (18), and the other is connected to the inlet of the deaerator (9).

5. The steam-water circulation system for a steam generator according to claim 2, characterized in that: The outlet of the condenser (6) is divided into two paths after passing through the condensate pump (8), one of which is connected to the inlet of the start-up water supply tank (7), and the other is connected to the inlet of the deaerator (9) through the eighth valve group (19).

6. The steam-water circulation system for a steam generator according to claim 1, characterized in that: The water outlet of the steam-water separator (3) is connected to the inlet of the start-up water supply tank (7) through the ninth valve group (20).

7. The steam-water circulation system for a steam generator according to claim 1, characterized in that: The outlet of the starting water supply tank (7) is connected to the inlet of the evaporation section (2-1) of the heat transfer tube of the steam generator via the starting water supply pump (10) and the tenth valve group (21).

8. The steam-water circulation system for a steam generator according to claim 2, characterized in that: The steam extraction port of the steam turbine (4) is connected to the inlet of the deaerator (9) via the twelfth valve group (23).

9. The steam-water circulation system for a steam generator according to claim 1, characterized in that: The outlet of the deaerator (9) is connected to the inlet of the evaporation section (2-1) of the heat transfer tube of the steam generator via the main feed water pump (11) and the eleventh valve group (22).

10. The steam-water circulation system for a steam generator according to claim 1, characterized in that: It also includes a reactor (1), which is connected to the primary side of the steam generator (2).

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