Search

CN-122014375-A - Supercritical carbon dioxide circulation self-adaptive system and adjusting method thereof

CN122014375ACN 122014375 ACN122014375 ACN 122014375ACN-122014375-A

Abstract

The invention discloses a supercritical carbon dioxide circulating self-adaptive system and an adjusting method thereof, and belongs to the technical field of power generation systems. The system comprises a supercritical CO 2 Brayton cycle subsystem, a working medium adjusting and switching subsystem and a monitoring control subsystem, wherein the working medium adjusting and switching subsystem is selectively communicated with the cycle subsystem through a switchable flow path control unit, the working medium adjusting and switching subsystem comprises a working medium separating and purifying module, a pure component storage tank group and a working medium preparing and injecting unit, the separating and purifying, the storing and the injecting according to the proportion of mixed working medium can be realized, the monitoring control subsystem collects the environmental temperature and the heat source parameters, the controller automatically determines the type and the proportion of target working medium according to the environmental temperature and the heat source parameters, the working medium switching is completed, and the flow of the working medium is dynamically adjusted. The invention solves the problem that the type and the proportion of working media cannot be rapidly switched according to the day and night and seasonal fluctuation of the ambient temperature in the prior art, realizes the separation and the recovery of the components of the mixed working media, and can rapidly respond to the change of the heat source parameters.

Inventors

  • DENG QINGHUA
  • LIU ANQI
  • LI JUN

Assignees

  • 西安交通大学

Dates

Publication Date
20260512
Application Date
20260306

Claims (10)

  1. 1. The supercritical carbon dioxide circulating self-adaptive system is characterized by comprising a supercritical CO 2 Brayton circulating subsystem, a working medium adjusting and switching subsystem and a monitoring control subsystem, wherein the working medium adjusting and switching subsystem is selectively communicated with the supercritical CO 2 Brayton circulating subsystem through a switchable flow path control unit; The working medium regulating and switching subsystem comprises a working medium separating and purifying module, a pure component storage tank group, a working medium preparing and injecting unit and a supercritical CO 2 Brayton cycle subsystem, wherein the working medium separating and purifying module is used for separating and purifying mixed working medium from the supercritical CO 2 Brayton cycle subsystem into single-component working mediums; The monitoring control subsystem comprises an ambient temperature sensor, a heat source parameter sensor and a controller, wherein the controller is respectively in signal connection with the ambient temperature sensor, the heat source parameter sensor, a switchable flow path control unit, a working medium separation and purification module, a pure component storage tank group and a working medium preparation and injection unit.
  2. 2. The supercritical carbon dioxide cycle adaptive system according to claim 1, wherein the supercritical CO 2 brayton cycle subsystem comprises a first cooler (1-1), a compressor (1-2), a regenerator (1-3), a first heater (1-4) and a turbine (1-5), wherein the switchable flow path control unit comprises a first three-way reversing valve (1-6) and a first shut-off valve (1-7); the system comprises a compressor (1-2), a heat regenerator (1-3), a heat absorbing side of a first heater (1-4), a turbine (1-5) and a heat releasing side of the heat regenerator (1-3), wherein an outlet of the first cooler (1-1) is connected to an inlet of a first three-way reversing valve (1-6) in sequence, a first outlet of the first three-way reversing valve (1-6) is communicated with the inlet of the first cooler (1-1), a second outlet of the first three-way reversing valve (1-6) is communicated with an inlet of a working medium adjusting and switching subsystem, and an outlet of the working medium adjusting and switching subsystem is connected with the inlet of the first cooler (1-1) through a first stop valve (1-7).
  3. 3. The supercritical carbon dioxide circulating self-adaptive system according to claim 2, wherein the working medium preparation and injection unit comprises a mixer (2-24), a first variable-frequency working medium pump (2-25) and a second heater (2-26), wherein an outlet of the mixer (2-24) is connected with an inlet of a heat absorption side of the second heater (2-26) through the first variable-frequency working medium pump (2-25) and used for pressurizing the mixed target working medium to supercritical pressure, an outlet of the heat absorption side of the second heater (2-26) is used as an outlet of a working medium regulating and switching subsystem and is connected with a first stop valve (1-7), an inlet of a heat emission side of the second heater (2-26) is connected with an outlet of a heat emission side of the first heater (1-4), an inlet of the heat emission side of the first heater (1-4) is communicated with a heat source, an outlet of the heat emission side of the second heater (2-26) is used for outputting smoke, and an inlet of the mixer (2-24) is connected with an outlet of a pure component storage tank group.
  4. 4. A supercritical carbon dioxide cycle self-adaptation system according to claim 3, characterized in that the switchable flow path control unit further comprises a second three-way reversing valve (1-8), the outlet of the heat release side of the first heater (1-4) being connected to the inlet of the second three-way reversing valve (1-8), the first outlet of the second three-way reversing valve (1-8) being connected to the inlet of the heat release side of the second heater (2-26), the second outlet of the second three-way reversing valve (1-8) being arranged for outputting flue gases.
  5. 5. The supercritical carbon dioxide cycle self-adaptive system according to claim 3, wherein the working medium separation and purification module comprises a third three-way reversing valve (2-2), a separator (2-3), a CO 2 purification device (2-4), a fourth three-way reversing valve (2-8), a fifth three-way reversing valve (2-9), a He purification device (2-10), a second stop valve (2-13), an H 2 S absorption tower (2-14), an H 2 S analysis tower (2-15), a second cooler (2-18) and a third stop valve (2-20); Wherein the inlet of the third three-way reversing valve (2-2) is used as the second outlet of the first three-way reversing valve (1-6) connected with the inlet of the separator (2-3) by the inlet of the working medium adjusting and switching subsystem, the first outlet of the third three-way reversing valve (2-2) is connected with the inlet of the fifth three-way reversing valve (2-9), the first outlet of the fifth three-way reversing valve (2-9) is connected with the first inlet of the H 2 S absorption tower (2-14), the first outlet of the absorption tower (2-14) is connected with the inlet of the separator (2-3) by the third stop valve (2-20), the second outlet of the separator (2-3) is connected with the inlet of the CO 2 purifying device (2-4), the first outlet of the CO 2 purifying device (2-4) is connected with the first inlet of the pure component tank set, the second outlet of the CO 2 purifying device (2-4) is connected with the first inlet of the fourth three-way reversing valve (2-8), the first outlet of the fourth three-way reversing valve (2-8) is connected with the inlet of the third three-way reversing valve (2-8) of the pure component tank set (2-4), the second outlet of the He purifying device (2-10) is connected with the inlet of the separator (2-3) through a second stop valve (2-13), the second outlet of the fifth three-way reversing valve (2-9) is connected with the inlet of the He purifying device (2-10), the second outlet of the absorption tower (2-14) is connected with the inlet of the H 2 S absorption tower (2-15), the first outlet of the H 2 S absorption tower (2-15) is connected with the third inlet of the pure component storage tank group, and the second outlet of the H 2 S absorption tower (2-15) is connected with the third inlet of the H 2 S absorption tower (2-14) through a second cooler (2-18).
  6. 6. The supercritical carbon dioxide circulation self-adaptation system according to claim 5, wherein the working medium separation and purification module further comprises a pressure reducing valve (2-1) and a second variable frequency working medium pump (2-19), the second cooler (2-18) is connected to a third inlet of the H 2 S absorption tower (2-14) through the second variable frequency working medium pump (2-19), and a second outlet of the first three-way reversing valve (1-6) is connected to an inlet of the third three-way reversing valve (2-2) through the pressure reducing valve (2-1).
  7. 7. The supercritical carbon dioxide cycle self-adaptive system according to claim 6, wherein the pure component tank group comprises a first regulating valve (2-21), a second regulating valve (2-22), a third regulating valve (2-23), a fourth stop valve (2-5), a fifth stop valve (2-6), a sixth stop valve (2-11), a seventh stop valve (2-16), a CO 2 tank (2-7), a He tank (2-12) and an H 2 S tank (2-17); The inlet of the CO 2 storage tank (2-7) is used as a first inlet of the pure component storage tank group and is connected with the outlet of the CO 2 purification device (2-4) through a fifth stop valve (2-6) and a fourth stop valve (2-5) in sequence, the inlet of the He storage tank (2-12) is used as a second inlet of the pure component storage tank group and is connected with the outlet of the He purification device (2-10) through a sixth stop valve (2-11), and the inlet of the H 2 S storage tank (2-17) is used as a third inlet of the pure component storage tank group and is connected with the outlet of the H 2 S analysis tower (2-15) through a seventh stop valve (2-16); The outlet of the H 2 S storage tank (2-17) is connected with the inlet of the mixer (2-24) through a first regulating valve (2-21), the outlet of the He storage tank (2-12) is connected with the inlet of the mixer (2-24) through a second regulating valve (2-22), and the outlet of the CO 2 storage tank (2-7) is connected with the inlet of the mixer (2-24) through a third regulating valve (2-23).
  8. 8. The method for adjusting the supercritical carbon dioxide circulation self-adaptive system is characterized by comprising the steps of adopting the supercritical carbon dioxide circulation self-adaptive system according to any one of claims 1-7, determining a target working medium type and a target proportion according to the ambient temperature detected by an ambient temperature sensor, controlling a switchable flow path control unit, a working medium separation and purification module, a pure component storage tank group and a working medium preparation and injection unit through a controller, switching the current working medium in a supercritical CO 2 Brayton cycle subsystem into a target working medium, and adjusting the working medium flow injected into the supercritical CO 2 Brayton cycle subsystem by the working medium preparation and injection unit according to the heat source temperature and flow detected by a heat source parameter sensor; when the ambient temperature is lower than a first temperature threshold value, a binary mixed working medium of CO 2 and He is selected as a target working medium type; When the ambient temperature is between the first temperature threshold and the second temperature threshold, selecting pure CO 2 working medium as a target working medium type; And when the ambient temperature is higher than a second temperature threshold, selecting the binary mixed working medium of CO 2 and H 2 S as the target working medium type.
  9. 9. The method for adjusting a supercritical carbon dioxide circulation self-adaptive system according to claim 8, wherein when the target working medium type is a binary mixed working medium of CO 2 and He or a binary mixed working medium of CO 2 and H 2 S, calculating a target critical temperature according to an ambient temperature and a preset heat exchange temperature difference, enabling the target critical temperature to be equal to the ambient temperature plus the preset heat exchange temperature difference, and determining a target proportion corresponding to the target critical temperature by querying a pre-stored working medium critical temperature and proportion relation database.
  10. 10. The method of claim 8, wherein the first temperature threshold is 288K and the second temperature threshold is 298K.

Description

Supercritical carbon dioxide circulation self-adaptive system and adjusting method thereof Technical Field The invention relates to the technical field of power generation systems, in particular to a supercritical carbon dioxide circulating self-adaptive system and an adjusting method thereof. Background Supercritical carbon dioxide recycling is a very potential high-efficiency energy conversion technology, and its advantages mainly result from the relatively low critical temperature (304K) and moderate critical pressure (7.38 MPa) of carbon dioxide (CO 2), which makes the system easier to implement and maintain in supercritical state operation. In this state, the physical properties of CO 2 are significantly changed, and the power consumption of the compressor is greatly reduced. However, the critical temperature of CO 2 also constitutes a major limitation in the application of the system, namely in the areas with hot drought and lack of water resources, the cooling process often depends on air cooling, the high-temperature environment easily causes the temperature of the working medium at the inlet of the compressor to be obviously higher than the critical temperature, so that the condition of the inlet of the compressor is far away from a near-critical area, the power consumption of the compressor is rapidly increased, and the circulation efficiency of the system is obviously reduced. In order to overcome these disadvantages, binary blendstocks based on CO 2, formed by blending inorganic or organic additives, have received considerable attention. By adjusting the components of the mixture, the critical temperature of the working medium can be changed, so that the working medium is matched with the local climate conditions, and the compressor is ensured to run in a near critical area at high efficiency all the time. The mixed working medium based on CO 2 becomes a research hot spot in a plurality of fields such as solar power stations, industrial waste heat recovery, geothermal power generation and the like. However, the existing research on the CO 2 mixed working medium still has obvious defects. First, in an actual operating environment employing air cooling for heat dissipation, a CO 2 mixture of a fixed formulation is not effective against diurnal or seasonal fluctuations in ambient temperature, which makes it difficult to maintain the inlet parameters of the compressor near the working medium critical point. The existing system does not have the capability of rapidly switching the type of working medium according to the change of the ambient temperature and separating and recovering the original mixed working medium in real time. Secondly, in the application scene that heat source parameters such as gas turbine waste heat recovery can obviously fluctuate, the adjustment capability of the existing system is insufficient. Besides the need of adjusting the critical characteristic of the working medium in response to the change of the environmental temperature, the system can dynamically adjust the flow of the circulating working medium according to the real-time change of heat source parameters such as the temperature and the flow of the heat source, so as to maximize the waste heat recovery efficiency and maintain the stable operation of the system. Therefore, the current technical scheme lacks a self-adaptive adjusting system capable of rapidly switching, separating and recycling mixed working medium components according to the ambient temperature and simultaneously adjusting the working medium flow in real time according to the fluctuation of a heat source. Disclosure of Invention The invention aims to provide a supercritical carbon dioxide circulation self-adaptive system and an adjusting method thereof, which overcome the defects of the prior art, and provide the self-adaptive system and the method which can rapidly switch the type and the proportion of working media according to the change of the ambient temperature, separate and recycle the mixed working media components and dynamically regulate and control the flow of the working media according to the heat source parameters. The invention solves the technical problems by the following technical proposal: The invention provides a supercritical carbon dioxide circulation self-adaptive system which comprises a supercritical CO 2 Brayton cycle subsystem, a working medium adjusting and switching subsystem and a monitoring control subsystem, wherein the working medium adjusting and switching subsystem is selectively communicated with the supercritical CO 2 Brayton cycle subsystem through a switchable flow path control unit, the working medium adjusting and switching subsystem comprises a working medium separating and purifying module, a pure component storage tank set, a working medium separating and purifying module, a working medium preparing and injecting unit and a pure component storage tank set, the working medium separating and purifying modul