CN117167105A - Supercritical carbon dioxide cyclic power generation peak regulation system and peak regulation method - Google Patents

Abstract

The invention belongs to the technical field related to advanced power cycle power generation. It discloses a supercritical carbon dioxide cycle power generation peak-shaving system and a peak-shaving method. The turbine mechanical equipment of the supercritical carbon dioxide cycle power generation peak-shaving system mainly includes a turbine and a compressor. and a heat exchanger, in which the main compressor or re-compressor is arranged in connection with the turbine and driven by the turbine, and the remaining compressors are connected with independent drive structures. The present invention arranges the main compressor or re-compressor and the turbine with a connecting shaft. Through the connecting shaft arrangement of the turbine and the compressor, the turbine can directly drive the compressor, thereby reducing the additional energy loss caused by the motor driving the compressor, which is beneficial to Improve efficiency; other compressors are arranged independently on separate shafts, so that the shaft speeds of other compressors can be flexibly adjusted under peak load, and can flexibly adapt to changes in peak load, which is conducive to optimizing and obtaining optimal operating parameters under peak load. This ensures that the power generation efficiency of the system will not be significantly reduced in peak load-shaving scenarios.

Description

A supercritical carbon dioxide cycle power generation peak-shaving system and peak-shaving method

Technical field

The invention belongs to the technical field related to advanced power cycle power generation, and more specifically, relates to a supercritical carbon dioxide cycle power generation peak-shaving system and peak-shaving method.

Background technique

Concentrated Solar Power (CSP) systems equipped with heat storage devices can achieve flexible regulation of output power. They can not only provide stable power as a baseload power station, but are also expected to become a clean and reliable peaking power station. , used to absorb excess photovoltaic power and wind power in future high-proportion renewable energy systems, thereby promoting large-scale grid integration of renewable energy power.

Among the many CSP technologies, tower solar thermal power generation technology combines high-temperature heat absorption, heat storage devices and supercritical CO ₂ (supercritical CO ₂ , S-CO ₂ for short) Brayton cycle, which can further improve power generation efficiency and reduce power generation costs. has great potential and has received widespread attention in recent years. As an important thermal power conversion equipment of the CSP system, the S-CO ₂ cycle has a significant impact on the operating performance of the CSP system. Research on S-CO ₂ cycle design optimization and operating parameter regulation is very important.

Although the existing supercritical CO ₂ cycle system has great potential in improving power generation efficiency and reducing power generation costs when used for power generation, it can only ensure high power generation efficiency under rated load, and there are problems when it is used in peaking scenarios. This solves the problem that power generation efficiency will be significantly reduced due to changes in peak load. Therefore, in the face of the urgent peak load regulation demand of high-proportion renewable energy systems in the future, how to determine the optimal design of cycle equipment so that the cycle can operate flexibly, efficiently, and safely under complex changing load conditions requires in-depth discussion.

Contents of the invention

In view of the above defects or improvement needs of the existing technology, the present invention provides a supercritical carbon dioxide cycle power generation peak shaving system and a peak shaving method, which solves the problems that arise when the existing supercritical CO ₂ cycle system is used in peak shaving scenarios. The problem that the power generation efficiency will be greatly reduced when the peak load changes can meet the requirements of flexible operation of the cycle under partial load, and takes into account the high efficiency of the cycle, making it suitable for peak load-shaving scenarios.

In order to achieve the above object, according to one aspect of the present invention, a supercritical carbon dioxide cycle power generation peak shaving system is provided. The turbine mechanical equipment of the supercritical carbon dioxide cycle power generation peak shaving system includes a turbine, a pre-compressor, a main compressor and a Re-compressor, wherein the main compressor or the re-compressor is arranged in connection with the turbine and is driven by the turbine, and the remaining compressors are connected with independent driving structures.

According to the supercritical carbon dioxide cycle power generation peak-shaving system provided by the present invention, when the required peak-shaving load is 30%-55% of the rated load, the main compressor and the turbine are connected to the shaft, and the pre-compressor An independent drive structure is connected to the re-compressor respectively;

When the required peak load is 55%-100% of the rated load, the re-compressor is connected to the turbine shaft, and the pre-compressor and the main compressor are respectively connected with independent driving structures.

According to the supercritical carbon dioxide cycle power generation peak-shaving system provided by the present invention, the supercritical carbon dioxide cycle power generation peak-shaving system also includes: a high-temperature regenerator, a low-temperature regenerator, a precooler, a diverter valve, an intercooler and a heater. ;

The outlet of the turbine is connected to the first inlet of the high-temperature regenerator, the first outlet of the high-temperature regenerator is connected to the first inlet of the low-temperature regenerator, and the third inlet of the high-temperature regenerator is connected to the first inlet of the high-temperature regenerator. The two outlets are connected to the inlet of the heater, the outlet of the heater is connected to the inlet of the turbine, the first outlet of the low temperature regenerator is connected to the inlet of the precooler, and the precooling The outlet of the compressor is connected to the inlet of the pre-compressor, and the outlet of the pre-compressor is connected to the inlet of the intercooler and the inlet of the re-compressor respectively through the diverter valve. The outlet is connected to the inlet of the main compressor, the outlet of the main compressor is connected to the second inlet of the low-temperature regenerator, and the second outlet of the low-temperature regenerator is connected to the third outlet of the high-temperature regenerator. The two inlets are connected, and the outlet of the recompressor is connected to the second inlet of the high-temperature regenerator.

According to the supercritical carbon dioxide cycle power generation and peak shaving system provided by the present invention, the heating medium in the heater is molten salt; the diverting ratio of the diverting valve is 0.5-0.6.

According to the supercritical carbon dioxide cycle power generation peak-shaving system provided by the present invention, the inlet medium temperature of the turbine is greater than or equal to 600°C; the inlet medium temperatures of the pre-compressor, the main compressor and the re-compressor are respectively greater than 30.98℃.

According to another aspect of the present invention, a supercritical carbon dioxide cycle power generation peak-shaving method is provided. Based on the supercritical carbon dioxide cycle power generation peak-shaving system described in any one of the above, the method includes:

The main compressor or the re-compressor is connected to the turbine and driven by the turbine, and the remaining compressors are connected to an independent drive structure, so that the required peak load is 30% of the rated load. - Peak shaving within 100% range.

According to the supercritical carbon dioxide cycle power generation peak-shaving method provided by the present invention, when the required peak-shaving load is 30%-55% of the rated load, the main compressor and the turbine are arranged in a connecting shaft, and the pre-compression The machine and the re-compressor are respectively connected to independent drive structures;

When the required peak load is 55%-100% of the rated load, the re-compressor and the turbine coupling shaft are arranged, and the pre-compressor and the main compressor are respectively connected to independent driving structures.

According to the supercritical carbon dioxide cycle power generation peak shaving method provided by the present invention, when the main compressor and the turbine connecting shaft arrangement are adopted, as the required peak shaving load decreases, the main compressor and the The shaft speed of the recompressor gradually decreases, and the shaft speed of the pre-compressor gradually increases.

According to the supercritical carbon dioxide cycle power generation peak-shaving method provided by the present invention, when the re-compressor and the turbine connecting shaft arrangement are adopted, as the required peak-shaving load decreases, the shaft speed of the re-compressor decreases. Gradually decrease, the shaft speed of the main compressor first decreases and then increases, and the shaft speed of the pre-compressor gradually increases.

According to the supercritical carbon dioxide cycle power generation peak-shaving method provided by the present invention, during the required peak-shaving load change process, the split ratio of the system is kept unchanged; wherein the split ratio is the working fluid flow rate of the main compressor and the The ratio of the total flow rate of the working fluid between the main compressor and the re-compressor.

Generally speaking, compared with the existing technology through the above technical solutions conceived by the present invention, the supercritical carbon dioxide cycle power generation peak-shaving system and peak-shaving method provided by the present invention:

1. Arrange the main compressor or re-compressor and the turbine with a connecting shaft, and arrange the other compressors independently on separate shafts. Through the connecting shaft arrangement of the turbine and the compressor, the turbine can directly drive the compressor, thereby reducing the time required for the motor to drive the compressor. The additional energy loss caused by this is conducive to improving efficiency; and other compressors are arranged with independent shafts, so that the shaft speeds of other compressors can be flexibly adjusted, and the shaft speeds of the main compressor or re-compressor can also be adjusted through the turbine. When used in peaking scenarios, the three compressors can independently adjust the shaft speed as the peaking load changes, so that they can flexibly adapt to changes in the peaking load, which is conducive to optimizing and obtaining the optimal operating parameters under the peaking load. This ensures that the system power generation efficiency will not be significantly reduced in peak load-shaving scenarios;

2. This system can not only meet the requirements for flexible operation of the cycle under partial load, but also take into account the efficient performance of the cycle and is suitable for peak load-shaving scenarios;

3. In-depth consideration is given to the operating characteristics of the three types of compressors under different loads, including the power consumption characteristics of the three types of compressors and the performance change characteristics with load changes, and then based on different peak regulation depth requirements, different cycle setting schemes are proposed. It is conducive to maximizing the power generation efficiency of the cycle in peak shaving scenarios.

Description of drawings

Figure 1 is a schematic diagram of a supercritical carbon dioxide cycle power generation and peak shaving system when the main compressor and turbine coupling shaft are arranged according to the present invention;

Figure 2 is a schematic diagram of the supercritical carbon dioxide cycle power generation and peak shaving system provided by the present invention when the compressor and turbine are arranged in a connecting shaft;

Figure 3 is a system schematic diagram of Comparative Example 1 and Comparative Example 2 provided by the present invention;

Figure 4 is a system schematic diagram of Comparative Example 3 and Comparative Example 4 provided by the present invention.

Throughout the drawings, the same reference numbers refer to the same elements or structures, wherein:

1. Turbine; 2. High temperature regenerator; 3. Low temperature regenerator; 4. Precooler; 5. Precompressor; 6. Diverter valve; 7. Intercooler; 8. Main compressor; 9. Then compressor; 10. Heater.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

Please refer to Figures 1 and 2. The present invention provides a supercritical carbon dioxide cycle power generation peak-shaving system. The peak-shaving system includes a supercritical carbon dioxide cycle system. The turbine mechanical equipment of the supercritical carbon dioxide cycle system includes turbine 1, Pre-compressor 5, main compressor 8 and re-compressor 9, wherein the main compressor 8 or the re-compressor 9 is connected to the turbine 1 and driven by the turbine 1, and the remaining compression The machine is connected with an independent drive structure.

The peak shaving system is formed by a supercritical carbon dioxide cycle system. The supercritical carbon dioxide cycle system can be a Brayton cycle system, which is a power generation system using supercritical carbon dioxide as a working medium. The supercritical carbon dioxide cycle system usually includes a compressor and a turbine 1, as well as other related structures for realizing the power generation cycle. The implementation of the cycle system is well known to those skilled in the art and will not be described in detail. In this embodiment, the circulation system is provided with three compressors, namely pre-compressor 5, main compressor 8 and re-compressor 9.

Furthermore, this embodiment proposes that the main compressor 8 or the re-compressor 9 is connected to the turbine 1, that is, driven by the turbine 1, and the other compressors are set to independent drive form, that is, an independent split-axis arrangement. , can be driven by an independent motor, making the circulation system suitable for peak load-shaving scenarios. Specifically, first of all, this embodiment considers that the thermal performance analysis of the S-CO ₂ cycle shows that the total power consumption of the compressor can account for 25%-30% of the output power of turbine 1, so the compression power consumption is huge. The coupling arrangement between the turbine 1 and the compressor allows the turbine 1 to directly drive the compressor, thus reducing the additional energy loss caused by the electric motor driving the compressor, thereby improving efficiency.

Secondly, this embodiment also takes into account that the operating pressure ratios and working fluid flow rates of multiple compressors in the circulation system are significantly different, and the rotational speeds of multiple compressors are different, which requires relatively independent control under changing working conditions, that is, In the variable load peak shaving operation scenario, each compressor needs to adjust the pressure ratio and flow rate by adjusting the shaft speed. Therefore, in this embodiment, one compressor is selected to be connected to the turbine 1, and the other compressors are independently driven. The other compressors can be connected to an electric motor for driving.

Specifically, for the connecting shaft arrangement scheme of turbine 1 and main compressor 8, the shaft speed of turbine 1 remains consistent with the shaft speed of main compressor 8, while the shaft speeds of pre-compressor 5 and re-compressor 9 can be flexibly adjusted. ; For the connecting shaft arrangement scheme of turbine 1 and re-compressor 9, the shaft speed of turbine 1 remains consistent with the shaft speed of re-compressor 9, while the shaft speeds of pre-compressor 5 and main compressor 8 can be flexibly adjusted. Therefore, the solution of this embodiment can not only meet the requirements for flexible operation of the cycle under partial load, but also take into account the efficient performance of the cycle.

The supercritical carbon dioxide cycle power generation and peak shaving system provided by the present invention proposes to arrange the main compressor 8 or the re-compressor 9 in conjunction with the turbine 1, and other compressors to be arranged independently in separate shafts, and the turbine 1 is coupled to the compressor. Turbine 1 can directly drive the compressor, thereby reducing the additional energy loss caused by the motor driving the compressor, thereby improving efficiency; and other compressors are arranged independently on separate shafts, so that the shaft speeds of other compressors can be flexibly adjusted. The shaft speed of the compressor or re-compressor can also be adjusted through the turbine. When used in peak shaving scenarios, the three compressors can independently adjust the shaft speed as the peak load changes, thus being able to flexibly adapt to the peak load. The change is conducive to optimizing and obtaining the optimal operating parameters under peak load, thereby ensuring that the system power generation efficiency will not be significantly reduced under peak load scenarios; the system can not only meet the requirements for flexible cyclic operation under partial load, but also take into account The efficient performance of the cycle is suitable for peak load shaving scenarios.

Further, research shows that the supercritical carbon dioxide cycle power generation peak shaving system can be used to load the rated peak shaving load by selecting the main compressor 8 or the re-compressor 9 to be connected to the turbine 1, while the other compressors are independently driven. Peak shaving within the load range of 30%-100% can achieve efficient and flexible operation of dozens to hundreds of MW installed capacity cycles under 30%-100% load demand.

The supercritical carbon dioxide cycle peak-shaving system selected in this embodiment is equipped with three compressors: a pre-compressor, a main compressor and a re-compressor. Through the introduction of the pre-compressor, an intermediate cooling process is introduced on the basis of the re-compression cycle, thus forming a partial Cooling cycle. Compared with the recompression cycle, this cycle can further reduce compressor power consumption, thereby improving cycle efficiency.

Further, when the required peak load is 30%-55% of the rated load, the main compressor 8 is connected to the turbine 1, and the pre-compressor 5 and the re-compressor 9 are connected to each other respectively. It is connected with an independent drive structure; when the required peak load is 55%-100% of the rated load, the re-compressor 9 is connected to the turbine 1, and the pre-compressor 5 and the main compressor Machines 8 are respectively connected with independent driving structures.

This embodiment considers that under high load, the power consumption of the re-compressor is significantly the highest among the three types of compressors. Arranging the re-compressor and the turbine connecting shaft can minimize the additional power consumption caused by the motor driving the compressor. Therefore, in The thermal efficiency of this arrangement is higher under high load; as the load decreases, the performance of the main compressor among the three types of compressors attenuates most obviously. In the cycle of the main compressor and turbine coupling arrangement, the main compressor pressure ratio under partial load The change is minimal, so the main compressor cycle efficiency is higher, and the turbine operating capacity is also minimally attenuated. Therefore, the thermal efficiency of the main compressor and turbine coupling shaft arrangement is higher when dealing with deep load adjustment.

That is, according to different peak shaving depth requirements, there are two mechanical layout forms of turbine 1, so that the supercritical carbon dioxide cycle system can show higher operating efficiency in different variable load intervals. One is that most of the peak shaving loads are cyclic. When the rated power is 30%-55%, the main compressor 8 and turbine 1 are connected with each other. Secondly, when the peak load is mostly 55%-100% of the rated power of the cycle, the re-compressor 9 and turbine 1 are used. In the coupling arrangement, the mechanical power consumed by the compressor coupled to turbine 1 is provided by turbine 1, and the remaining compressors are driven by independent electric motors.

Specifically, the turbine 1 and the main compressor 8 can be arranged in a connected shaft arrangement or the turbine 1 and the re-compressor 9 can be arranged in a connected shaft arrangement according to actual peak shaving requirements. When the actual required peak load is concentrated at 30%-55% of the rated load, the scheme of connecting the main compressor 8 and the turbine 1 can be adopted; when the actual required peak load is concentrated at 55% of the rated load %-100%, adopt the scheme of arranging the compressor 9 and the turbine 1 in connection with each other. The specific actual required peak load can be judged based on the user's actual operating load within a year. When the user's actual operating load within a year is mostly concentrated at 30%-55% of the rated load, the main compressor 8 and 8 can be used for this user. The scheme of arranging the connecting shaft of turbine 1; when the actual operating load of the user within a year is mostly concentrated at 55%-100% of the rated load, the scheme of arranging the connecting shaft of compressor 9 and turbine 1 can be used for this user.

Further, specifically, the present invention selects the supercritical CO ₂ partial cooling cycle as the research object. The supercritical carbon dioxide cycle system also includes: high-temperature regenerator 2, low-temperature regenerator 3, pre-cooler 4, split flow Valve 6, intercooler 7 and heater 10; that is, the main compressor 8 or re-compressor 9 in the partial cooling cycle is connected to the turbine 1, and the remaining compressors are independently arranged in separate shafts; the supercritical CO ₂ part The cooling cycle includes: turbine 1, high temperature regenerator 2, low temperature regenerator 3, precooler 4, precompressor 5, diverter valve 6, intercooler 7, main compressor 8, recompressor 9, heating Device 10. The main compressor 8 or re-compressor 9 is connected to the turbine 1, and the mechanical power consumed is provided by the turbine 1, and the remaining compressors are driven by independent electric motors.

Specifically, the outlet of the turbine 1 is connected to the first inlet of the high-temperature regenerator 2, and the first outlet of the high-temperature regenerator 2 is connected to the first inlet of the low-temperature regenerator 3, so The second outlet of the high-temperature regenerator 2 is connected to the inlet of the heater 10, the outlet of the heater 10 is connected to the inlet of the turbine 1, and the first outlet of the low-temperature regenerator 3 is connected to the inlet of the heater 10. The inlet of the pre-compressor 5 is connected, and the outlet of the pre-compressor 5 is connected to the inlet of the main compressor 8 and the inlet of the re-compressor 9 respectively through the diverter valve 6. The main compressor 8 The outlet of is connected to the second inlet of the low-temperature regenerator 3, the second outlet of the low-temperature regenerator 3 is connected to the second inlet of the high-temperature regenerator 2, and the outlet of the recompressor 9 is connected to The second inlet of the high-temperature regenerator 2 is connected, the precooler 4 is provided at the inlet of the pre-compressor 5 , and the intercooler 7 is provided at the inlet of the main compressor 8 .

Further, the heating medium in the heater 10 is molten salt; the molten salt can be formed by solar heating. The split ratio of the diverter valve 6 is 0.5-0.6; the split ratio of the diverter valve 6 is the ratio of the flow rate of the working fluid flowing into the main compressor 8 from the diverter valve 6 to the total flow rate of the working fluid at the inlet of the diverter valve 6. Research has shown that this range The split ratio within the range can achieve better power generation efficiency under different peak loads.

Further, the inlet medium temperature of the turbine 1 is greater than or equal to 600°C; the inlet medium temperatures of the pre-compressor 5, the main compressor 8 and the re-compressor 9 are respectively greater than 30.98°C. When the turbine 1 inlet temperature is higher than 600°C, the supercritical CO ₂ cycle has a thermal efficiency advantage over the traditional water vapor Rankine cycle, and as the temperature increases, the thermal efficiency advantage becomes more obvious. The compressor inlet temperature needs to be maintained above the critical temperature of 30.98°C, and lowering the compressor inlet temperature is conducive to improving cycle thermal efficiency.

Further, the present invention also provides a supercritical carbon dioxide cycle power generation peak shaving method. Based on the supercritical carbon dioxide cycle power generation peak shaving system described in any of the above embodiments, the method includes: converting the main compressor 8 or The recompressor 9 is connected to the turbine 1 and is driven by the turbine 1. The remaining compressors are connected to an independent drive structure, so that the required peak load is in the range of 30%-100% of the rated load. Peak shaving within.

Further, when the required peak load is 30%-55% of the rated load, the main compressor 8 and the turbine 1 are arranged in a connecting shaft, and the pre-compressor 5 and the re-compressor 9 Independent driving structures are connected respectively; when the required peak load is 55%-100% of the rated load, the re-compressor 9 and the turbine 1 are arranged in a connecting shaft, and the pre-compressor 5 and the main The compressors 8 are respectively connected to independent drive structures.

Specifically, according to tests, when high-temperature molten salt is used as the heat transfer medium to increase the inlet temperature of circulating turbine 1 to 750°C and the inlet temperatures of the three compressors are all 35°C, turbine 1 and main compressor 8 are connected The operating efficiency of the partial cooling cycle under 30%-100% load is 43.01%-49.85%. The operating efficiency of the partial cooling cycle between turbine 1 and re-compressor 9 is 41.58% under 30%-100% load. -50.38%.

Comparing the operating efficiency of the two circulation systems with turbine 1 mechanical arrangement under variable load conditions, it can be seen that the circulation system with turbine 1 and main compressor 8 connected shafts has an efficiency advantage when dealing with deep peak shaving (30%-55% load) Obviously, the cycle in which the turbine 1 and the compressor 9 are connected to each other is more efficient under higher load (55%-100% load). This is mainly due to the fact that in a cycle where turbine 1 and main compressor 8 are connected with each other, under low load conditions with deep peak shaving, the output power of turbine 1 hardly decreases when absorbing unit heat, and the power consumption of the compressor is lower. Therefore, Cycle efficiency is higher at low loads.

Furthermore, the present invention provides a specific control strategy for the supercritical carbon dioxide cycle peak-shaving system when used for peak-shaving, and the optimal operating parameters under different loads can be optimized and obtained according to the control strategy. Specifically, when the main compressor 8 and the turbine 1 are connected with each other, as the required peak load decreases, the shaft speeds of the main compressor 8 and the re-compressor 9 gradually increase. decreases, the shaft speed of the pre-compressor 5 gradually increases.

Further, when the re-compressor 9 and the turbine 1 are connected with each other, as the required peak load decreases, the shaft speed of the re-compressor 9 gradually decreases, and the main compressor The shaft speed of 8 first decreases and then increases, and the shaft speed of the pre-compressor 5 gradually increases.

Further, during the change of the required peak load, the split ratio of the system is kept unchanged; wherein the split ratio is the ratio of the working fluid flow of the main compressor 8 to the main compressor 8 and the re-compressor. 9 ratio of the total flow rate of working fluid.

Specifically, when actually running, the cycle is heated by high-temperature ternary chloride salt and cooled by air. The inlet temperature of turbine 1 is 750°C, and the inlet temperature of the three compressors is 35°C. Under the design working conditions, it is the rated load. The power generation efficiency of the circulating system where turbine 1 and main compressor 8 are connected, that is, the system shown in Figure 1, is 49.85%. The power generation efficiency of the circulating system where turbine 1 and re-compressor 9 are connected, that is, the system shown in Figure 2 is 50.38%. Under non-design conditions, the maximum pressure, minimum pressure, intercooling pressure and split ratio of the circulation system can be adjusted by flexibly adjusting the shaft speed of each compressor and the split valve 6. The shaft speed of turbine 1 and the main compressor 8 or the compressor 9 remains consistent.

For the cycle where turbine 1 and main compressor 8 are connected, the main compressor 8 and re-compressor 9 shaft speeds decrease as the load decreases, but the pre-compressor 5 shaft speed increases as the load decreases. , the opening of diverter valve 6 is almost unchanged. For the cycle where the turbine 1 and the re-compressor 9 are connected with each other, as the load decreases, the shaft speed of the re-compressor 9 decreases, and the shaft speed of the main compressor 8 first decreases and then when the required peak load is lower than 50% of the rated When the load increases, the rotation speed of the 5th axis of the pre-compressor increases, and the opening of the diverter valve 6 almost remains unchanged.

The reason why the compressor shaft speed increases as the load decreases is mainly to cope with the increasing compressor specific enthalpy. As a result, the maximum pressure, minimum pressure and intercooling pressure of the cycle gradually decrease, and the split ratio remains almost unchanged at about 0.56. That is, the split ratio can be 0.56.

Further, when the required peak load is 30%-55% of the rated load, the turbine 1 and the main compressor 8 are arranged in a connecting shaft, and within this load variation range, as the required peak load decreases , the shaft speeds of the main compressor 8 and the re-compressor 9 gradually decrease, and the shaft speed of the pre-compressor 5 gradually increases.

Further, when the required peak load is 55%-100% of the rated load, the turbine 1 and the re-compressor 9 are arranged in a connecting shaft, and within this load variation range, as the required peak load decreases , the shaft speeds of the main compressor 8 and the re-compressor 9 gradually decrease, and the shaft speed of the pre-compressor 5 gradually increases.

Further, the purpose of the present invention is to provide an efficient and flexible mechanical optimization layout scheme for the supercritical CO ₂ cycle turbine 1 suitable for peak-shaving scenarios. This scheme is based on the design parameter optimization and operation of the supercritical carbon dioxide cycle system. Relevant research on parameter control, determine the layout plan of circulation equipment and operating parameter control strategy, and optimize to obtain the best operating parameters and operating efficiency of the cycle under partial load.

Specifically, the present invention discloses a mechanical optimization layout scheme for supercritical CO ₂ cycle turbine 1 in a peak-shaving scenario. This scheme is proposed for a partially cooled supercritical CO ₂ cycle. The cycle consists of 1 turbine 1 and 3 turbines. It consists of a compressor, 2 regenerators, 1 heater and 2 air coolers. By optimizing the arrangement of turbine 1 and compressor, the cycle can be operated safely and efficiently under peak load conditions. The specific layout plan is that when frequently responding to deep peak shaving demands (load <55%), a plan is adopted in which turbine 1 is connected to the main compressor 8 and the main compressor 8 is driven by turbine 1; and when dealing with changes in When the load demand is relatively high (load > 55%), a solution is adopted in which turbine 1 and re-compressor 9 are connected and re-compressor 9 is driven by turbine 1; at the same time, the remaining compressors are arranged in separate shafts. , driven by an independent electric motor; under variable load conditions, the shaft speed of turbine 1 is adjusted according to the shaft speed of the connected compressor, and the other compressors independently adjust the shaft speed according to the actual pressure ratio and flow rate; the adjustment can be obtained through optimization Variable load operating parameters and efficiency of the cycle under peak scenarios. This solution takes into account the flexibility and efficiency of supercritical CO ₂ cycle regulation and operation under variable load conditions, and helps to improve the power supply economy and reliability of high-temperature solar thermal power peaking power stations based on supercritical CO ₂ cycle .

Compared with the scheme in which the turbine 1, the main compressor 8, the re-compressor 9 and the pre-compressor 5 are all connected with each other, the present invention makes it easier to flexibly regulate the compressor shaft speed in the peak shaving scenario to achieve deep peak shaving of the cycle; Compared with the scheme in which the turbine 1, the main compressor 8, the re-compressor 9 and the pre-compressor 5 are arranged separately on separate axes, the scheme proposed by the present invention has higher thermal efficiency under all working conditions, and can still meet the requirements of various conditions under variable working conditions. Flexible regulation of the shaft speed of the turbine 1 mechanical equipment; this invention responds to different types of peak shaving requirements and optimizes a more efficient mechanical layout scheme of the circulating turbine 1. When the load demand is mostly between 30% and 55%, it is recommended to adopt a transparent When the load demand is mostly between 55% and 100%, it is recommended to use a cycle with turbine 1 and 9 re-compressors connected with each other. The following is further explained through specific examples and comparative examples:

Specific example 1:

As shown in Figure 1, the mechanical arrangement of the supercritical CO ₂ cycle turbine 1 in Example 1 of the present invention is that the turbine 1 is connected to the main compressor 8, and the main compressor 8 is directly driven by the turbine 1 and then compressed The compressor 9 and the pre-compressor 5 are respectively arranged on separate shafts and driven by independent electric motors. The rated power of the cycle is 100MW. The maximum, minimum, intermediate cooling pressure and split ratio of the cycle obtained through optimization at 100% rated load are 25MPa, 5.75MPa, 8.38MPa and 0.561 respectively. The shaft speeds of turbine 1 and main compressor 8 are 15500rpm, the shaft speed of re-compressor 9 is 18700rpm, the shaft speed of pre-compressor 5 is 4100rpm, and the cycle rated power generation efficiency is 49.85%.

Specific example 2:

As shown in Figure 1, Example 2 of the present invention uses the same cycle as Example 1. In the peak load-shaving scenario, the cycle output power needs to be adjusted according to the changing load demand. The shaft speed of turbine 1 and the shaft speed of main compressor 8 are adjusted in real time, and the shaft speeds of compressor 9 and pre-compressor 5 are adjusted independently. When the load demand is reduced to 30% of the rated value, the maximum, minimum, intermediate cooling pressure and split ratio of the cycle are adjusted to 10.44MPa, 4.04MPa, 7.49MPa and 0.560 respectively, and the power generation efficiency of the cycle is reduced to 43.01%.

Specific example 3:

As shown in Figure 2, the layout scheme of the supercritical CO ₂ cycle turbine 1 in Example 3 of the present invention is that the re-compressor 9 is connected to the turbine 1, and the re-compressor 9 is directly driven by the turbine 1 and pre-compressed. The compressor 5 and the main compressor 8 are arranged on separate shafts and are driven by independent electric motors respectively. The rated power of the cycle is 100MW. The highest, lowest, intermediate cooling pressure and split ratio of the cycle obtained through optimization at 100% rated load are 25MPa, 5.56MPa, 8.40MPa and 0.561 respectively. The shaft speeds of turbine 1 and recompressor 9 are 19000rpm, the shaft speed of main compressor 8 is 15600rpm, the shaft speed of pre-compressor 5 is 4400rpm, and the cycle rated power generation efficiency is 50.38%.

Specific example 4:

As shown in Figure 2, Example 4 of the present invention uses the same cycle as Example 3. In the peak shaving scenario, the shaft speed of turbine 1 and the shaft speed of re-compressor 9 are adjusted in real time, and the shaft speeds of main compressor 8 and pre-compressor 5 are adjusted independently. When the load demand is reduced to 30% of the rated value, the maximum, minimum, intermediate cooling pressure and split ratio of the cycle are adjusted to 11.03MPa, 4.16MPa, 7.23MPa and 0.557 respectively, and the power generation efficiency of the cycle is reduced to 41.58%.

Comparative example 1:

As shown in Figure 3, Comparative Example 1 of the present invention is a scheme in which the supercritical CO ₂ cycle turbine 1 is mechanically arranged in all parts of the axis. In this scheme, the turbine 1 is directly connected to the generator to generate electricity, and then the compressor 9 and the pre-compressor 5 and main compressor 8 are driven by independent electric motors respectively. The rated power of the cycle is still 100MW. The highest, lowest, intermediate cooling pressure and split ratio of the cycle obtained through optimization at 100% rated load are 25MPa, 5.73MPa, 8.51MPa and 0.561 respectively. The rated power generation efficiency of the cycle is 49.21%.

Comparative example 2:

As shown in Figure 3, Comparative Example 2 of the present invention uses the same cycle as Comparative Example 1. In the peak load-shaving scenario, the shaft speed of each turbine 1 machine is independently controlled. When the load demand is reduced to 30% of the rated value, the maximum, minimum, intermediate cooling pressure and split ratio of the cycle are adjusted to 11.05MPa, 3.81MPa, 7.28MPa and 0.558 respectively, and the power generation efficiency of the cycle is reduced to 40.69%.

Comparative example 3:

As shown in Figure 4, the mechanical arrangement scheme of the supercritical CO ₂ cycle turbine 1 in Comparative Example 3 of the present invention is that the turbine 1 and the pre-compressor 5 are connected with each other. The pre-compressor 5 is directly driven by the turbine 1, and the main The compressor 8 and the re-compressor 9 are respectively arranged on separate shafts and driven by independent electric motors. The rated power of the cycle is still 100MW. The highest, lowest, intermediate cooling pressure and split ratio of the cycle obtained through optimization at 100% rated load are 25MPa, 5.12MPa, 8.57MPa and 0.561 respectively. The rated power generation efficiency of the cycle is 50.10%.

Comparative example 4:

As shown in Figure 4, Comparative Example 4 of the present invention uses the same cycle as Comparative Example 3. In the peak shaving scenario, the shaft speed of turbine 1 and the shaft speed of pre-compressor 5 are adjusted in real time, and the shaft speeds of main compressor 8 and re-compressor 9 are adjusted independently. When the load demand is reduced to 30% of the rated value, the maximum, minimum, intermediate cooling pressure and split ratio of the cycle are adjusted to 11.36MPa, 4.46MPa, 6.76MPa and 0.562 respectively, and the power generation efficiency of the cycle is reduced to 39.63%.

Through the analysis and comparison of specific examples and comparative examples, it can be found that the two mechanical optimization layout schemes of the supercritical CO ₂ cycle turbine 1 proposed by the present invention can better balance the flexibility and efficiency of the cycle in peak-shaving operation scenarios. sex. Compared with the scheme of the complete shaft arrangement of the turbine 1 and the continuous arrangement of the turbine 1 and the pre-compressor 5, the scheme of the continuous arrangement of the turbine 1 and the re-compressor 9 proposed by the present invention can further improve the power generation efficiency and the rated load. The absolute values of power generation efficiency can be increased by 1.17% and 0.28% respectively. When dealing with the demand for deep peak shaving, the scheme of connecting the turbine 1 and the main compressor 8 proposed by the present invention has obvious efficiency advantages. For example, when the load is 30% of the rated value, the cycle power generation efficiency can still reach 43.01%, which is relatively high. Compared with the scheme of all-shaft arrangement of turbine 1, 5-shaft arrangement of turbine 1 and pre-compressor, and 9-shaft arrangement of turbine 1 and re-compressor, the absolute value of cycle efficiency can be increased by 2.32%, 3.38% and 1.43%.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements, etc., made within the spirit and principles of the present invention, All should be included in the protection scope of the present invention.

Claims (10)

1. A supercritical carbon dioxide cycle power generation peak shaving system, characterized in that the turbine mechanical equipment of the supercritical carbon dioxide cycle power generation peak shaving system includes a turbine, a pre-compressor, a main compressor and a re-compressor, wherein the main compressor The compressor or the re-compressor is connected to the turbine and driven by the turbine, and the remaining compressors are connected with independent drive structures. 2. The supercritical carbon dioxide cycle power generation peak-shaving system according to claim 1, characterized in that when the required peak-shaving load is 30%-55% of the rated load, the main compressor is connected to the turbine. Shaft arrangement, the pre-compressor and the re-compressor are respectively connected with independent driving structures; When the required peak load is 55%-100% of the rated load, the re-compressor is connected to the turbine shaft, and the pre-compressor and the main compressor are respectively connected with independent driving structures. 3. The supercritical carbon dioxide cycle power generation peak-shaving system according to claim 1, characterized in that the supercritical carbon dioxide cycle power generation peak-shaving system further includes: a high-temperature regenerator, a low-temperature regenerator, a precooler, and a shunt. Valves, intercoolers and heaters; The outlet of the turbine is connected to the first inlet of the high-temperature regenerator, the first outlet of the high-temperature regenerator is connected to the first inlet of the low-temperature regenerator, and the third inlet of the high-temperature regenerator is connected to the first inlet of the high-temperature regenerator. The two outlets are connected to the inlet of the heater, the outlet of the heater is connected to the inlet of the turbine, the first outlet of the low temperature regenerator is connected to the inlet of the precooler, and the precooling The outlet of the compressor is connected to the inlet of the pre-compressor, and the outlet of the pre-compressor is connected to the inlet of the intercooler and the inlet of the re-compressor respectively through the diverter valve. The outlet is connected to the inlet of the main compressor, the outlet of the main compressor is connected to the second inlet of the low-temperature regenerator, and the second outlet of the low-temperature regenerator is connected to the third outlet of the high-temperature regenerator. The two inlets are connected, and the outlet of the recompressor is connected to the second inlet of the high-temperature regenerator. 4. The supercritical carbon dioxide cycle power generation peak-shaving system according to claim 3, characterized in that the heating medium in the heater is molten salt; the diverting ratio of the diverting valve is 0.5-0.6. 5. The supercritical carbon dioxide cycle power generation peak-shaving system according to claim 1, characterized in that the inlet medium temperature of the turbine is greater than or equal to 600°C; the pre-compressor, the main compressor and the re-compressor are The inlet medium temperature of the compressor is greater than 30.98℃ respectively. 6. A supercritical carbon dioxide cycle power generation peak-shaving method, characterized in that, based on the supercritical carbon dioxide cycle power generation peak-shaving system according to any one of the above claims 1-5, the method includes: The main compressor or the re-compressor is connected to the turbine and driven by the turbine, and the remaining compressors are connected to an independent drive structure, so that the required peak load is 30% of the rated load. - Peak shaving within 100% range. 7. The supercritical carbon dioxide cycle power generation peak-shaving method as claimed in claim 6, characterized in that when the required peak-shaving load is 30%-55% of the rated load, the main compressor and the turbine are set. Coupling shaft arrangement, the pre-compressor and the re-compressor are respectively connected to independent driving structures; When the required peak load is 55%-100% of the rated load, the re-compressor and the turbine coupling shaft are arranged, and the pre-compressor and the main compressor are respectively connected to independent driving structures. 8. The supercritical carbon dioxide cycle power generation peak-shaving method according to claim 6, characterized in that when the main compressor and the turbine coupling arrangement are adopted, as the required peak-shaving load decreases, The shaft speed of the main compressor and the re-compressor gradually decreases, and the shaft speed of the pre-compressor gradually increases. 9. The supercritical carbon dioxide cycle power generation peak-shaving method as claimed in claim 6, characterized in that when the arrangement of the re-compressor and the turbine coupling is adopted, as the required peak-shaving load decreases, The shaft speed of the recompressor gradually decreases, the shaft speed of the main compressor first decreases and then increases, and the shaft speed of the pre-compressor gradually increases. 10. The supercritical carbon dioxide cycle power generation peak-shaving method as claimed in claim 6, characterized in that during the required peak-shaving load change process, the split ratio of the system is kept unchanged; wherein the split ratio is the main compression ratio. The ratio of the working fluid flow of the machine to the total working fluid flow of the main compressor and the re-compressor.