A supercritical carbon dioxide cycle generator set water spray desuperheating system

Abstract

This invention discloses a supercritical carbon dioxide cycle generator set water spray desuperheating system, comprising a supercritical carbon dioxide cycle power generation system and a water spray desuperheating system; the supercritical carbon dioxide cycle power generation system includes a heater, a screen-type superheater, a final-stage superheater, and a turbine; the water spray desuperheating system includes a first desuperheating water injection point, a second desuperheating water injection point, and a liquid-water separation system; the heater outlet is sequentially connected to the turbine inlet via the first desuperheating water injection point, the screen-type superheater, the second desuperheating water injection point, and the final-stage superheater; the turbine outlet is connected to the inlet of the liquid-water separation system; the liquid outlet of the liquid-water separation system is connected to the first and second desuperheating water injection points; and the gas outlet of the liquid-water separation system is connected to the heater inlet. This system can solve various problems caused by carbon dioxide desuperheating.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of supercritical carbon dioxide cycle power generation, and relates to a water injection desuperheating system of a supercritical carbon dioxide cycle power generating unit. BACKGROUND

[0002] The supercritical carbon dioxide cycle is a new energy conversion technology taking carbon dioxide as a working medium, and has advantages of high energy conversion efficiency, wide working range, flexible regulation performance, compact system and the like, and has broad application prospects in fields of coal-fired thermal power generation, nuclear energy, photo-thermal power generation and waste heat recovery.

[0003] Compared with the steam Rankine cycle, the supercritical carbon dioxide cycle has fewer main gas temperature regulation means when applied to coal-fired power generation, and the adjustable parameters mainly include fuel quantity, working medium flow and air quantity and the like. However, these methods have slow response and the accuracy is difficult to guarantee. The water injection desuperheating method in the steam Rankine cycle can realize flexible and accurate temperature regulation, and is a commonly used and effective main gas temperature regulation method. If the carbon dioxide injection desuperheating method is applied to the supercritical carbon dioxide cycle power generating unit to regulate the main gas temperature by analogy with the steam Rankine cycle unit, the following shortcomings exist: (1) if the temperature of the injected carbon dioxide is high, the enthalpy rise of the carbon dioxide under the main gas pressure is small, and a very large carbon dioxide flow is required to realize rapid temperature regulation; (2) if the temperature of the injected carbon dioxide is low, the temperature gradient in the main gas pipeline and the desuperheater is large, and the thermal stress of the pipeline and the equipment is large, which affects the safety of the equipment; and (3) the compression power required to improve the pressure of the desuperheating carbon dioxide is large, which leads to the decline of the overall performance of the unit. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a water injection desuperheating system of a supercritical carbon dioxide cycle power generating unit, which can solve various problems caused by carbon dioxide desuperheating.

[0005] To achieve the above purpose, the present application discloses a water injection desuperheating system of a supercritical carbon dioxide cycle power generating unit, comprising a supercritical carbon dioxide cycle power generation system and a water injection desuperheating system.

[0006] The supercritical carbon dioxide cycle power generation system comprises a heater, a screen superheater, a final stage superheater and a turbine; and the water injection desuperheating system comprises a first desuperheating water injection point, a second desuperheating water injection point and a liquid water separation system.

[0007] The outlet of the heater is connected to the inlet of the turbine through a first desuperheating water injection point, a screen superheater, a second desuperheating water injection point and a final superheater in sequence.

[0008] The supercritical carbon dioxide cycle power generation system further comprises a high-temperature regenerator, a low-temperature regenerator, a re-compressor, a main compressor and a pre-cooler.

[0009] The water injection desuperheating system comprises a first liquid water separator, a second liquid water separator, a third liquid water separator and a water tank.

[0010] The outlet of the turbine is connected to the inlet of the first liquid water separator through the low-pressure side of the high-temperature regenerator, the water outlet at the bottom of the first liquid water separator is connected to the inlet of the water tank, the gas outlet at the top of the first liquid water separator is connected to the inlet of the second liquid water separator, the water outlet at the bottom of the second liquid water separator is connected to the inlet of the water tank, the gas outlet at the top of the second liquid water separator is divided into two paths, one of which is connected to the inlet of the third liquid water separator and the other of which is connected to the inlet of the re-compressor, the gas outlet at the top of the third liquid water separator is connected to the high-pressure side inlet of the low-temperature regenerator through the main compressor, the high-pressure side outlet of the low-temperature regenerator and the outlet of the re-compressor are connected to the high-pressure side inlet of the high-temperature regenerator, and the high-pressure side outlet of the high-temperature regenerator is connected to the inlet of the heater.

[0011] The outlet at the bottom of the third liquid water separator is connected to the inlet of the water tank, and the outlet of the water tank is connected to the first desuperheating water injection point and the second desuperheating water injection point.

[0012] The outlet of the water tank is connected to the first desuperheating water injection point and the second desuperheating water injection point through a water treatment system and a desuperheating water pump in sequence.

[0013] The gas outlet at the top of the first liquid water separator is connected to the inlet of the second liquid water separator through the low-pressure side of the low-temperature regenerator.

[0014] The gas outlet at the top of the second liquid water separator is connected to the inlet of the third liquid water separator through the pre-cooler.

[0015] The circulating working medium of the supercritical carbon dioxide cycle power generation system is carbon dioxide.

[0016] The working medium of the water injection desuperheating system is water.

[0017] In operation, the desuperheating water sprayed from the first desuperheating water spraying point absorbs the heat of the main flow of carbon dioxide in the pipeline, so that the temperature of the main flow of carbon dioxide is reduced to prevent the screen superheater from over-temperature; the desuperheating water sprayed from the second desuperheating water spraying point absorbs the heat of the main flow of carbon dioxide in the pipeline, so that the temperature of the main flow of carbon dioxide is reduced to adjust the medium temperature at the outlet of the final stage superheater, the carbon dioxide mixed working medium containing water vapor enters the turbine to do work, and finally enters the liquid water separation system for separation.

[0018] The present application has the following beneficial effects:

[0019] In the specific operation of the supercritical carbon dioxide cycle generator set water injection desuperheating system, the outlet of the heater is connected in sequence with the first desuperheating water spraying point, the screen superheater, the second desuperheating water spraying point and the inlet of the turbine, the desuperheating water sprayed from the first desuperheating water spraying point absorbs the heat of the main flow of carbon dioxide in the pipeline, so that the temperature of the main flow of carbon dioxide is reduced to prevent the screen superheater from over-temperature; the desuperheating water sprayed from the second desuperheating water spraying point absorbs the heat of the main flow of carbon dioxide in the pipeline, so that the temperature of the main flow of carbon dioxide is reduced to adjust the medium temperature at the outlet of the final stage superheater, solving various problems caused by carbon dioxide desuperheating. It should be noted that the present application uses water injection desuperheating to adjust the main gas parameters of the supercritical carbon dioxide cycle generator set, and utilizes the advantage of high specific heat of water, so that a small amount of water injection can realize flexible and accurate adjustment of the temperature of the supercritical carbon dioxide main gas.

[0020] Further, by utilizing the high outlet parameter of the turbine, the water vapor in the carbon dioxide mixed working medium will not condense in the turbine, and liquid water separators are arranged at the inlet of the low temperature regenerator, the inlet of the precooler and the inlet of the compressor to discharge the condensed water out of the supercritical carbon dioxide power generation system, so that no negative impact is generated on the main compressor and the re-compressor. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The figure is a structural schematic diagram of the present application.

[0022] Among them, 1 is the first desuperheating water spraying point, 2 is the screen superheater, 3 is the second desuperheating water spraying point, 4 is the final stage superheater, 5 is the turbine, 6 is the high temperature regenerator, 7 is the re-compressor, 8 is the first liquid water separator, 9 is the second liquid water separator, 10 is the precooler, 11 is the third liquid water separator, 12 is the main compressor, 13 is the low temperature regenerator, 14 is the heater, 15 is the desuperheating water pump, 16 is the water treatment system, and 17 is the water tank. DETAILED DESCRIPTION

[0023] In order to make the person skilled in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments, and are not intended to limit the scope of the present application. In addition, in the following description, the description of the well-known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0024] The structural schematic diagrams according to the disclosed embodiments of the present application are shown in the drawings. These drawings are not drawn to scale, in which some details are enlarged for the purpose of clear expression, and some details can be omitted. The shapes of various regions, layers and their relative size and positional relationship shown in the drawings are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and the regions / layers with different shapes, sizes and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0025] With reference to Figure 1 The supercritical carbon dioxide cycle generator set water injection desuperheating system described in the present application comprises a supercritical carbon dioxide cycle power generation system and a water injection desuperheating system. The supercritical carbon dioxide cycle power generation system comprises a screen superheater 2, a final stage superheater 4, a turbine 5, a high temperature regenerator 6, a low temperature regenerator 13, a re-compressor 7, a main compressor 12, a pre-cooler 10 and a heater 14. The water injection desuperheating system comprises a first desuperheating water injection point 1, a second desuperheating water injection point 3, a first liquid water separator 8, a second liquid water separator 9, a third liquid water separator 11, a water tank 17, a water treatment system 16 and a desuperheating water pump 15.

[0026] The outlet of the heater 14 is connected to the inlet of the turbine 5 in sequence through the first desuperheating water injection point 1, the screen superheater 2, the second desuperheating water injection point 3 and the final superheater 4; the outlet of the turbine 5 is connected to the inlet of the first liquid water separator 8 through the low-pressure side of the high-temperature regenerator 6; the outlet of the first liquid water separator 8 is connected to the inlet of the water tank 17; the outlet of the second liquid water separator 9 is connected to the inlet of the water tank 17; the outlet of the second liquid water separator 9 is divided into two paths, one of which is connected to the inlet of the third liquid water separator 11 through the pre-cooler 10, and the other of which is connected to the inlet of the re-compressor 7; the outlet of the third liquid water separator 11 is connected to the inlet of the main compressor 12 and the high-pressure side of the low-temperature regenerator 13; the outlet of the high-pressure side of the low-temperature regenerator 13 and the outlet of the re-compressor 7 are connected to the inlet of the high-pressure side of the high-temperature regenerator 6; the outlet of the high-pressure side of the high-temperature regenerator 6 is connected to the inlet of the heater 14;

[0027] The outlet of the third liquid water separator 11 is connected to the inlet of the water tank 17; the outlet of the water tank 17 is connected to the first desuperheating water injection point 1 and the second desuperheating water injection point 3 in sequence through the water treatment system 16 and the desuperheating water pump 15.

[0028] In the embodiment, the circulating working medium of the supercritical carbon dioxide cycle power generation system is carbon dioxide.

[0029] In the embodiment, the working medium of the water injection desuperheating system is water.

[0030] The working process of the present application is as follows:

[0031] The water output by the water tank 17 is desalted after being treated by the water treatment system 16, and is then pumped to the first desuperheating water injection point 1 and the second desuperheating water injection point 3 by the desuperheating water pump 15; the desuperheating water injected from the first desuperheating water injection point 1 absorbs the heat of the main stream of carbon dioxide in the pipeline, so that the temperature of the main gas is reduced, and the screen superheater 2 is prevented from overheating; the desuperheating water injected from the second desuperheating water injection point 3 absorbs the heat of the main stream of carbon dioxide in the pipeline, so that the temperature of the main gas is reduced, and the main function is to accurately adjust the outlet temperature of the main gas of the final superheater 4; the carbon dioxide mixed working medium containing water vapor enters the turbine 5 to do work, and then is heat-released in the high-temperature regenerator 6, and then enters the first liquid water separator 8, the condensed liquid water is collected into the water tank 17, the mixed gas which is not condensed enters the low-temperature regenerator 13 to release heat, the temperature of the mixed working medium is reduced, and then the mixed working medium enters the second liquid water separator 9 to be separated, the condensed liquid water is collected into the water tank 17, the mixed gas which is not condensed enters the pre-cooler 10 to be cooled, the temperature of the mixed working medium is further reduced, and then the mixed working medium enters the third liquid water separator 11 to be separated, the condensed liquid water is collected into the water tank 17, and the remaining carbon dioxide working medium enters the main compressor 12.

[0032] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit it. Although the present application has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the specific embodiments of the present application can be modified or equivalently replaced without departing from the spirit and scope of the present application, and any modification or equivalent replacement should be covered in the protection scope of the claims of the present application.

Claims

1. A supercritical carbon dioxide cycle power generating unit water spray desuperheating system, characterized by, The supercritical carbon dioxide cycle power generation system and the water injection desuperheating system are provided. The supercritical carbon dioxide cycle power generation system comprises a heater (14), a screen superheater (2), a final stage superheater (4) and a turbine (5); the water injection desuperheating system comprises a first water injection point (1), a second water injection point (3) and a liquid water separation system. The outlet of the heater (14) is connected to the inlet of the turbine (5) through the first water injection point (1), the screen superheater (2), the second water injection point (3) and the final stage superheater (4) in sequence; the outlet of the turbine (5) is connected to the inlet of the liquid water separation system; the liquid outlet of the liquid water separation system is connected to the first water injection point (1) and the second water injection point (3); the gas outlet of the liquid water separation system is connected to the inlet of the heater (14). The supercritical carbon dioxide cycle power generation system further comprises a high temperature regenerator (6), a low temperature regenerator (13), a re-compressor (7), a main compressor (12) and a pre-cooler (10). The water injection desuperheating system comprises a first liquid water separator (8), a second liquid water separator (9), a third liquid water separator (11) and a water tank (17). The outlet of the turbine (5) is connected to the inlet of the first liquid water separator (8) through the low pressure side of the high temperature regenerator (6); the water outlet at the bottom of the first liquid water separator (8) is connected to the inlet of the water tank (17); the gas outlet at the top of the first liquid water separator (8) is connected to the inlet of the second liquid water separator (9); the water outlet at the bottom of the second liquid water separator (9) is connected to the inlet of the water tank (17); the gas outlet at the top of the second liquid water separator (9) is divided into two paths, one of which is connected to the inlet of the third liquid water separator (11) and the other of which is connected to the inlet of the re-compressor (7); the gas outlet at the top of the third liquid water separator (11) is connected to the high pressure side inlet of the low temperature regenerator (13) through the main compressor (12); the high pressure side outlet of the low temperature regenerator (13) and the outlet of the re-compressor (7) are connected to the high pressure side inlet of the high temperature regenerator (6); the high pressure side outlet of the high temperature regenerator (6) is connected to the inlet of the heater (14). The outlet at the bottom of the third liquid water separator (11) is connected to the inlet of the water tank (17); the outlet of the water tank (17) is connected to the first water injection point (1) and the second water injection point (3).

2. The supercritical carbon dioxide cycle power generating unit water spray desuperheating system according to claim 1, characterized by, The outlet of the water tank (17) is connected to the first water injection point (1) and the second water injection point (3) through the water treatment system (16) and the desuperheating water pump (15) in sequence.

3. The supercritical carbon dioxide cycle power generating unit water spray desuperheating system of claim 1, wherein, The gas outlet at the top of the first liquid water separator (8) is connected to the inlet of the second liquid water separator (9) through the low pressure side of the low temperature regenerator (13).

4. The supercritical carbon dioxide cycle power generating unit water spray desuperheating system of claim 1, wherein, The gas outlet at the top of the second liquid water separator (9) is connected to the inlet of the third liquid water separator (11) through the pre-cooler (10).

5. The supercritical carbon dioxide cycle power generating unit water spray desuperheating system of claim 1, wherein, The circulating working medium of the supercritical carbon dioxide cycle power generation system is carbon dioxide.

6. The supercritical carbon dioxide cycle power generating unit water spray desuperheating system of claim 1, wherein, The working medium of the water injection desuperheating system is water.

7. The supercritical carbon dioxide cycle power generating unit water spray desuperheating system of claim 1, wherein, In working, the desuperheating water sprayed from the first desuperheating water spraying point (1) absorbs the heat of the main flow of carbon dioxide in the pipeline, so that the temperature of the main flow of carbon dioxide is reduced, and the screen superheater (2) is prevented from over-temperature; the desuperheating water sprayed from the second desuperheating water spraying point (3) absorbs the heat of the main flow of carbon dioxide in the pipeline, so that the temperature of the main flow of carbon dioxide is reduced, and the medium temperature at the outlet of the last-stage superheater (4) is adjusted; the carbon dioxide mixed working medium containing water vapor enters the turbine (5) to do work, and finally enters a liquid water separation system to be separated.

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