A high-efficiency supercritical carbon dioxide high-temperature gas-cooled reactor system and a method for operating the same

Abstract

The application discloses a kind of efficient supercritical carbon dioxide high temperature gas cooled reactor systems and its operating method, the system includes pre-cooler, main compressor, re-compressor, high temperature turbine, low temperature regenerator, high temperature regenerator, high temperature helium-supercritical carbon dioxide heat exchanger, low temperature helium-supercritical carbon dioxide heat exchanger and reactor.The application proposes the power generation system of two-stage split supercritical carbon dioxide cycle comprising high-temperature split re-compression cycle loop and low-temperature re-split reheat expansion cycle loop, by arranging high-temperature helium-supercritical carbon dioxide heat exchanger and low-temperature helium-supercritical carbon dioxide heat exchanger in power generation system, ensure the good matching of helium loop heat release temperature window and supercritical carbon dioxide power cycle loop heat absorption temperature window, realize the efficient cascade utilization of high-temperature gas cooled reactor helium loop large-span temperature interval heat.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nuclear power generation, and relates to a high-efficiency supercritical carbon dioxide high-temperature gas cooled reactor system and a running method thereof. BACKGROUND

[0002] The fourth generation nuclear power technology has better economy, higher safety, and can effectively solve the problems of nuclear waste disposal and nuclear proliferation, but the higher heat source temperature puts higher requirements on the power cycle and the working medium. As an advanced fourth generation nuclear power reactor technology, the high-temperature gas cooled reactor has inherent safety, can be modularly designed and constructed, and can realize multiple purposes such as power generation, hydrogen production and heat supply, and is considered to be the most promising fourth generation nuclear power technology. The successful grid-connected power generation of the high-temperature gas cooled reactor nuclear power station determines the leading position of the nuclear power technology at home and abroad.

[0003] The supercritical carbon dioxide cycle power generation technology uses carbon dioxide as the working medium and adopts a closed Brayton cycle mode to generate power. Compared with the traditional power generation mode using water and steam as the working medium and adopting the Rankine cycle, the supercritical carbon dioxide cycle power generation technology has the characteristics of high thermal efficiency, simple system, compact structure, wide application range and inherent safety, and is a revolutionary low-carbon power generation technology in the field of thermal power generation. Therefore, the supercritical carbon dioxide Brayton cycle is widely considered to be an ideal power generation cycle for the fourth generation advanced nuclear power system.

[0004] Considering that the supercritical carbon dioxide Brayton cycle is used to replace the original steam Rankine cycle, the characteristics of high temperature and high pressure (the core pressure is 7 MPa, and the core inlet / outlet temperature is 250 / 750 DEG C) of the high-temperature gas cooled reactor can be effectively utilized to improve the power generation efficiency; the supercritical carbon dioxide without phase change is used as the circulating working medium, so that the system has the ability of deep and rapid peak regulation, and in addition, the problems of two-phase instability and flow-induced vibration in the original steam generator can be solved; in the case of a first / second loop boundary break accident, the problem of reaction between steam and graphite and core materials can also be avoided.

[0005] A main heat exchanger is used between the high temperature gas cooled reactor and the supercritical carbon dioxide Brayton cycle to realize the heat work conversion between the first loop heat source system and the second loop power generation system. In order to ensure the reliability of the helium fan in the first loop, the design temperature of the helium fan is limited, which makes the heat release temperature interval of the helium in the first loop in the hot side of the main heat exchanger span larger, and the temperature drop is about 500 DEG C. For the currently recognized high-efficiency primary split recompression supercritical carbon dioxide cycle, the average heat absorption temperature is higher, which leads to a narrow heat absorption temperature window, so that the temperature rise of the cycle in the cold side of the main heat exchanger is about 100 DEG C. If the primary split recompression supercritical carbon dioxide Brayton cycle system is directly used for the high temperature gas cooled reactor, there is a problem that the heat release temperature window of the helium side in the first loop and the heat absorption temperature window of the supercritical carbon dioxide cycle are not matched well. The existence of this problem is not conducive to the full cooling of the helium in the first loop of the high temperature gas cooled reactor, and the heat in the lower temperature interval cannot be fully utilized, so as to affect the power generation efficiency of the whole system. SUMMARY

[0006] The purpose of the present application is to overcome the above-mentioned shortcomings of the prior art, and to provide an efficient supercritical carbon dioxide high temperature gas cooled reactor system and its operation method, to solve the problem that the heat release temperature window of the helium side in the first loop and the heat absorption temperature window of the supercritical carbon dioxide cycle are not matched well in the prior art.

[0007] An efficient supercritical carbon dioxide high temperature gas cooled reactor system, comprising a high temperature helium-supercritical carbon dioxide heat exchanger and a low temperature helium-supercritical carbon dioxide heat exchanger; the high temperature helium-supercritical carbon dioxide heat exchanger and the low temperature helium-supercritical carbon dioxide heat exchanger are jointly connected with a reactor;

[0008] The cold side outlet of the high temperature helium-supercritical carbon dioxide heat exchanger is connected with the inlet of a high temperature turbine, the outlet of the high temperature turbine is connected with the hot side inlet of a high temperature regenerator, the hot side outlet of the high temperature regenerator is connected with the hot side inlet of a low temperature regenerator, the hot side outlet of the low temperature regenerator is connected with a pre-cooler and a recompressor respectively, the outlet of the pre-cooler is connected with the inlet of a main compressor, the outlet of the main compressor is connected with the cold side inlet of the low temperature regenerator, the cold side outlet of the low temperature regenerator and the outlet of the recompressor are combined and connected with the cold side inlet of the low temperature helium-supercritical carbon dioxide heat exchanger and the cold side inlet of the high temperature regenerator respectively, and the cold side outlet of the high temperature regenerator is connected with the cold side outlet of the high temperature helium-supercritical carbon dioxide heat exchanger.

[0009] The cold side outlet of the low temperature helium-supercritical carbon dioxide heat exchanger is connected with a low temperature turbine, and the outlet of the low temperature turbine is merged into the hot side inlet of the low temperature regenerator.

[0010] Further improvements of the present application are as follows:

[0011] Preferably, the outlet of the reactor is connected to the hot side inlet of the high temperature helium-supercritical carbon dioxide heat exchanger, the hot side outlet of the high temperature helium-supercritical carbon dioxide heat exchanger is connected to the hot side inlet of the low temperature helium-supercritical carbon dioxide heat exchanger, and the hot side outlet of the low temperature helium-supercritical carbon dioxide heat exchanger is connected to the inlet of the reactor.

[0012] Preferably, a low temperature flow regulating valve is arranged between the hot side outlet of the low temperature recuperator and the re-compressor.

[0013] Preferably, the working pressure and temperature of the main compressor are near the critical point of carbon dioxide.

[0014] Preferably, a high temperature flow regulating valve is arranged between the cold side outlet of the low temperature recuperator and the cold side inlet of the low temperature helium-supercritical carbon dioxide.

[0015] Preferably, the main compressor, the re-compressor, the low temperature turbine and the high temperature turbine are coaxially arranged and jointly drive a motor.

[0016] Preferably, the low temperature recuperator, the high temperature recuperator, the high temperature helium-supercritical carbon dioxide heat exchanger and the low temperature helium-supercritical carbon dioxide heat exchanger are printed circuit board type heat exchangers.

[0017] A method for operating the above-mentioned high-efficiency supercritical carbon dioxide high temperature gas cooled reactor system, the high temperature helium gas output from the reactor releases heat in sequence through the high temperature helium-supercritical carbon dioxide heat exchanger and the low temperature helium-supercritical carbon dioxide heat exchanger, and then returns to the reactor;

[0018] The supercritical carbon dioxide output from the high temperature helium-supercritical carbon dioxide heat exchanger is expanded to do work in the high temperature turbine, and then enters the high temperature recuperator as a hot side to release heat. The supercritical carbon dioxide output from the hot side of the high temperature recuperator enters the low temperature recuperator as a hot side to be cooled. The supercritical carbon dioxide is cooled in the low temperature recuperator and then divided into two paths. One path is cooled in the pre-cooler and then enters the main compressor to be pressurized. The other path directly enters the re-compressor to be pressurized. The supercritical carbon dioxide output from the main compressor enters the low temperature recuperator as a cold side to be heated, and then merges with the supercritical carbon dioxide output from the re-compressor. The merged supercritical carbon dioxide is divided into two parts. One part enters the high temperature recuperator as a cold side to be heated. The other part enters the cold side of the low temperature helium-supercritical carbon dioxide to be heated. The supercritical carbon dioxide output from the high temperature recuperator enters the cold side of the high temperature helium-supercritical carbon dioxide heat exchanger to be heated, and then enters the high temperature turbine.

[0019] The supercritical carbon dioxide output from the low temperature helium-supercritical carbon dioxide enters the low temperature turbine. The supercritical carbon dioxide is expanded to do work in the low temperature turbine, and then merges into the hot side inlet of the low temperature recuperator.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] The application discloses a kind of high-efficiency supercritical carbon dioxide high temperature gas cooled reactor system, which includes pre-cooler, main compressor, re-compressor, high temperature turbine, low temperature regenerator, high temperature regenerator, high temperature helium-supercritical carbon dioxide heat exchanger, low temperature helium-supercritical carbon dioxide heat exchanger and reactor.The application proposes the power generation system of two-stage split supercritical carbon dioxide cycle containing high-temperature split re-compression cycle loop and low-temperature re-split reheat expansion cycle loop, by arranging high-temperature helium-supercritical carbon dioxide heat exchanger and low-temperature helium-supercritical carbon dioxide heat exchanger in the power generation system, ensure the good matching of helium loop heat release temperature window and supercritical carbon dioxide power cycle loop heat absorption temperature window, realize the efficient cascade utilization of high-temperature gas cooled reactor helium loop large-span temperature interval heat;In addition, the supercritical carbon dioxide power generation system equipment in the system is compact, and the floor space is small, which reduces the overall volume and cost of high-temperature gas cooled reactor unit.

[0022] The application also discloses a kind of high-efficiency supercritical carbon dioxide high temperature gas cooled reactor system operation method, which realizes the heat exchange of grading by high-temperature split re-compression supercritical carbon dioxide cycle and low-temperature re-split reheat expansion supercritical carbon dioxide cycle, realizes the cascade utilization of high-temperature gas cooled reactor large-span temperature interval heat;By adjusting the flow distribution at split and re-split device, ensure the efficient utilization of high-temperature gas cooled reactor heat under design condition and variable condition, realize efficient power generation. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the overall system diagram of the application.

[0024] Wherein, 1 is pre-cooler, 2 is main compressor, 3 is re-compressor, 4 is low temperature turbine, 5 is high temperature turbine, 6 is low temperature regenerator, 7 is high temperature regenerator, 8 is high temperature helium-supercritical carbon dioxide heat exchanger, 9 is low temperature helium-supercritical carbon dioxide heat exchanger, 10 is motor, 11 is reactor, 12 is low temperature flow regulating valve, 13 is high temperature flow regulating valve. DETAILED DESCRIPTION

[0025] The application will be further described in detail as follows in combination with the drawings:

[0026] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application; the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] Reference Figure 1 One of the embodiments of the present application is to disclose a kind of two-time shunt's high-efficiency supercritical carbon dioxide high-temperature gas cooled reactor system, comprising first loop and second loop;The first loop is the loop that reactor 11 is connected with high-temperature helium-supercritical carbon dioxide heat exchanger 8 and low-temperature helium-supercritical carbon dioxide heat exchanger 9 hot side;The second loop is supercritical carbon dioxide two-stage shunt circulation system, specifically comprising high-temperature circulation loop and low-temperature circulation loop;The high-temperature circulation loop is shunt recompression circulation loop;The low-temperature circulation loop is re-shunt reheated expansion loop.

[0028] The high-temperature circulation loop specifically includes pre-cooler 1, main compressor 2, recompression compressor 3, high-temperature turbine 5, low-temperature regenerator 6, high-temperature regenerator 7, high-temperature helium-supercritical carbon dioxide heat exchanger 8, low-temperature flow regulating valve 12;The low-temperature circulation loop specifically includes low-temperature turbine 4, low-temperature helium-supercritical carbon dioxide heat exchanger 9, high-temperature flow regulating valve 13.The second loop further includes generator 10.

[0029] The high-temperature circulation loop absorbs high-grade heat from reactor 11 through high-temperature helium-supercritical carbon dioxide heat exchanger 8 and realizes heat power conversion.The low-temperature circulation loop absorbs low-grade heat from reactor 11 through low-temperature helium-supercritical carbon dioxide heat exchanger 9 and realizes heat power conversion.

[0030] In the first loop, the hot side outlet of high-temperature helium-supercritical carbon dioxide heat exchanger 8 is communicated with the hot side inlet of low-temperature helium-supercritical carbon dioxide 9, the hot side outlet of low-temperature helium-supercritical carbon dioxide 9 is connected with the heat input port of reactor 11, and the heat output port of reactor 11 is connected with the hot side inlet of high-temperature helium-supercritical carbon dioxide heat exchanger 8.

[0031] In the second loop, the cold side outlet of the high-temperature helium-supercritical carbon dioxide heat exchanger 8 is connected with the inlet of the high-temperature turbine 5, the outlet of the high-temperature turbine 5 is communicated with the hot side inlet of the high-temperature regenerator 7, the hot side outlet of the high-temperature regenerator 7 is merged with the outlet of the low-temperature turbine 4 and is communicated with the hot side inlet of the low-temperature regenerator 6, the hot side outlet of the low-temperature regenerator 6 is divided into two routes, one route is communicated with the inlet of the main compressor 2 through the hot side of the pre-cooler 1, and the other route is communicated with the inlet of the re-compressor 3 through the low-temperature flow regulating valve 12. The outlet of the main compressor 2 is communicated with the cold side inlet of the low-temperature regenerator 6, the cold side outlet of the low-temperature regenerator 6 is merged with the outlet of the re-compressor 3 and is divided into two branches, one branch is connected with the cold side inlet of the high-temperature regenerator 7, the cold side outlet of the high-temperature regenerator 7 is communicated with the cold side inlet of the high-temperature helium-supercritical carbon dioxide heat exchanger 8, and the other branch is connected with the cold side inlet of the low-temperature helium-supercritical carbon dioxide heat exchanger 9, a high-temperature flow regulating valve 13 is arranged on the branch, the cold side outlet of the low-temperature helium-supercritical carbon dioxide heat exchanger 9 is communicated with the inlet of the low-temperature turbine 4, and the second loop constitutes a complete closed two-stage split supercritical carbon dioxide power cycle.

[0032] The main compressor 2, the re-compressor 3, the low-temperature turbine 4, the high-temperature turbine 5 and the generator 10 are coaxially arranged; the main compressor 2, the re-compressor 3, the low-temperature turbine 4 and the high-temperature turbine 5 jointly provide power for the generator 10.

[0033] As the preferred embodiment of the application, the pre-cooler 1, the low-temperature regenerator 6, the high-temperature regenerator 7, the high-temperature helium-supercritical carbon dioxide heat exchanger 8 and the low-temperature helium-supercritical carbon dioxide heat exchanger 9 adopt printed circuit board heat exchangers (PCHE) to realize the compactness, low resistance and high efficiency of the supercritical carbon dioxide Brayton cycle heat exchanger under the condition of large heat exchange capacity; the main compressor 2 works near the critical point of carbon dioxide to ensure that the supercritical carbon dioxide Brayton cycle has a relatively high cycle efficiency.

[0034] The specific working process of the application is as follows:

[0035] In the first loop, the high-temperature helium gas from the reactor 11 flows through the high-temperature helium-supercritical carbon dioxide heat exchanger 8 and the low-temperature helium-supercritical carbon dioxide heat exchanger 9 in sequence, and the heat in different temperature ranges is respectively transmitted to the high-temperature circulating loop and the low-temperature circulating loop in the second loop.

[0036] In the second loop, one route of supercritical carbon dioxide is heated by the cold side of the high-temperature helium-supercritical carbon dioxide heat exchanger 8, enters the high-temperature turbine 5 to expand and do work, and then is cooled by the hot side of the high-temperature regenerator 7, and is combined with another route of supercritical carbon dioxide which is expanded and does work by the low-temperature turbine 4, and then enters the low-temperature regenerator 6 to be cooled; the cooled supercritical carbon dioxide is divided into two routes, one of which is cooled by the precooler 1 and then pressurized by the main compressor 2, and then enters the low-temperature regenerator 6 to be heated by the cold side, and the other of which is pressurized by the low-temperature flow regulating valve 12 and then enters the re-compressor 3; the outlet of the re-compressor 3 and the outlet of the low-temperature regenerator 6 are combined, and then divided into two routes, one of which is heated by the cold side of the low-temperature helium-supercritical carbon dioxide heat exchanger 9 after passing through the high-temperature flow regulating valve 13, and the other of which is heated by the cold side of the high-temperature regenerator 7, and then is heated by the cold side of the high-temperature helium-supercritical carbon dioxide heat exchanger 8. Thus, the second loop constitutes a complete closed two-stage split supercritical carbon dioxide power cycle.

[0037] The low-temperature flow regulating valve 12 and the high-temperature flow regulating valve 13 in the second loop can realize flexible adjustment of the flow distribution ratio of the high-temperature cycle loop and the low-temperature cycle loop.

[0038] When the above specific operation is adopted, the high-temperature helium-supercritical carbon dioxide heat exchanger and the low-temperature helium-supercritical carbon dioxide heat exchanger in the power generation system ensure good matching of the helium loop heat release temperature window and the second loop supercritical carbon dioxide power cycle heat absorption temperature window, and realize efficient cascade utilization of the high-temperature gas cooled reactor heat in a large temperature interval; by adjusting the flow distribution of the split and re-split devices, efficient utilization of the high-temperature gas cooled reactor heat under design conditions and variable conditions is ensured, and efficient power generation is realized.

[0039] The above only describes preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high-efficiency supercritical carbon dioxide high-temperature gas-cooled reactor system, characterized in that: It comprises a high-temperature helium-supercritical carbon dioxide heat exchanger (8) and a low-temperature helium-supercritical carbon dioxide heat exchanger (9); the high-temperature helium-supercritical carbon dioxide heat exchanger (8) and the low-temperature helium-supercritical carbon dioxide heat exchanger (9) are connected to a reactor (11); The cold side outlet of the high-temperature helium-supercritical carbon dioxide heat exchanger (8) is connected to the inlet of the high-temperature turbine (5), the outlet of the high-temperature turbine (5) is connected to the hot side inlet of the high-temperature regenerator (7), the hot side outlet of the high-temperature regenerator (7) is connected to the hot side inlet of the low-temperature regenerator (6), the hot side outlet of the low-temperature regenerator (6) is respectively connected to the precooler (1) and the recompressor (3), the outlet of the precooler (1) is connected to the inlet of the main compressor (2), the outlet of the main compressor (2) is connected to the cold side inlet of the low-temperature regenerator (6), the cold side outlet of the low-temperature regenerator (6) and the outlet of the recompressor (3) are merged and respectively connected to the cold side inlet of the low-temperature helium-supercritical carbon dioxide heat exchanger (9) and the cold side inlet of the high-temperature regenerator (7), the cold side outlet of the high-temperature regenerator (7) is connected to the cold side outlet of the high-temperature helium-supercritical carbon dioxide heat exchanger (8); The cold side outlet of the low-temperature helium-supercritical carbon dioxide heat exchanger (9) is connected to a low-temperature turbine (4), and the outlet of the low-temperature turbine (4) is connected to the hot side inlet of the low-temperature regenerator (6); The outlet of the reactor (11) is connected to the hot side inlet of the high-temperature helium-supercritical carbon dioxide heat exchanger (8), the hot side outlet of the high-temperature helium-supercritical carbon dioxide heat exchanger (8) is connected to the hot side inlet of the low-temperature helium-supercritical carbon dioxide heat exchanger (9), and the hot side outlet of the low-temperature helium-supercritical carbon dioxide heat exchanger (9) is connected to the inlet of the reactor (11); A low-temperature flow regulating valve (12) is provided between the hot side outlet of the low-temperature regenerator (6) and the recompressor (3); A high-temperature flow regulating valve (13) is provided between the cold-side outlet of the low-temperature regenerator (6) and the cold-side inlet of the low-temperature helium-supercritical carbon dioxide (9).

2. The high-efficiency supercritical carbon dioxide high-temperature gas-cooled reactor system according to claim 1, characterized in that: The operating pressure and temperature of the main compressor (2) are near the critical point of carbon dioxide.

3. The high-efficiency supercritical carbon dioxide high-temperature gas-cooled reactor system according to claim 1, characterized in that: The main compressor (2), the recompressor (3), the low-temperature turbine (4) and the high-temperature turbine (5) are coaxially arranged and jointly drive the motor (10).

4. The high-efficiency supercritical carbon dioxide high-temperature gas-cooled reactor system according to claim 1, characterized in that: The low-temperature regenerator (6), the high-temperature regenerator (7), the high-temperature helium-supercritical carbon dioxide heat exchanger (8), and the low-temperature helium-supercritical carbon dioxide heat exchanger (9) are all printed circuit board type heat exchangers.

5. A method for operating a high-efficiency supercritical carbon dioxide high-temperature gas-cooled reactor system according to claim 1, characterized in that: The high-temperature helium output from the reactor (11) passes through the high-temperature helium-supercritical carbon dioxide heat exchanger (8) and the low-temperature helium-supercritical carbon dioxide heat exchanger (9) in sequence to release heat, and then returns to the reactor (11); The supercritical carbon dioxide output from the high-temperature helium-supercritical carbon dioxide heat exchanger (8) is output to the high-temperature turbine (5) for expansion and work, and then enters the high-temperature regenerator (7) as the hot side to release heat. The supercritical carbon dioxide output from the hot side of the high-temperature regenerator (7) enters the low-temperature regenerator (6) as the hot side to cool down. After cooling down in the low-temperature regenerator (6), the supercritical carbon dioxide is divided into two paths. One path enters the main compressor (2) for pressure boosting after cooling down in the precooler (1), and the other path directly enters the recompressor (3) for pressure boosting. The supercritical carbon dioxide outputted from the machine (2) enters the low-temperature regenerator (6) for heating on the cold side, and then merges with the supercritical carbon dioxide outputted from the recompressor (3) and is divided into two parts. One part enters the high-temperature regenerator (7) for heating on the cold side, and the other part enters the cold side of the low-temperature helium-supercritical carbon dioxide (9) for heating. The supercritical carbon dioxide outputted from the high-temperature regenerator (7) enters the cold side of the high-temperature helium-supercritical carbon dioxide heat exchanger (8) for heating, and the heated supercritical carbon dioxide enters the high-temperature turbine (5). The supercritical carbon dioxide output by the low-temperature helium-supercritical carbon dioxide (9) enters the low-temperature turbine (4), and after the supercritical carbon dioxide expands and performs work in the low-temperature turbine (4), it is collected into the hot side inlet of the low-temperature regenerator (6).

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