Cogeneration systems with integrated steam ejectors and peak-shaving operation methods

Abstract

This invention belongs to the field of combined heat and power (CHP) technology, and specifically relates to a CHP system with an integrated steam ejector and a peak-shaving operation method. The system includes a coal-fired boiler, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a steam cooler, a high-pressure regenerative heater, a low-pressure regenerative heater, a deaerator, a steam ejector, a main heat heater, and an auxiliary heat network heater. This system utilizes the coupling of the steam ejector, auxiliary heat network heater, and steam cooler to achieve efficient and flexible functions, possessing high electrical load regulation capability and resource utilization rate, maximizing its economic efficiency while meeting electrical and thermal load requirements.

Description

Technical Field

[0001] This invention belongs to the field of combined heat and power (CHP) technology, and specifically relates to a CHP system with an integrated steam ejector and a peak-shaving operation method. Background Technology

[0002] Cogeneration is an effective energy utilization method that can significantly improve fuel utilization. It is a globally recognized important measure for saving energy, improving the environment, and enhancing urban infrastructure functions. It has good economic and social benefits and is an important technical means to achieve a circular economy. However, under the pressure of climate change caused by carbon emissions, the world has begun the process of transitioning to low-carbon energy. With the advancement of my country's energy supply structure transformation, the proportion of coal-fired units has gradually decreased, while the proportion of renewable energy sources such as wind and solar power has gradually increased. This has put forward new requirements for the technological innovation of coal-fired units. At present, the challenges for coal-fired cogeneration units mainly come from the following two aspects. (1) The heating load remains high during the heating season. With the urbanization process and people's pursuit of a better life, the demand for regional heating is constantly expanding. (2) The heat and electricity load is unbalanced. The strong coupling of heat and electricity loads of cogeneration units and the "heat-determined power" operation mode have led to a significant decrease in their power generation load regulation capacity during the heating season, occupying a large amount of electricity market space, which is not conducive to the development of regional renewable energy and other low-carbon energy sources.

[0003] Currently, combined heat and power (CHP) units with integrated steam ejectors can improve heating capacity and achieve a certain degree of heat and electricity decoupling. However, there is still significant room for improvement in the electrical load regulation capability of existing systems. During the heating season, coal-fired units are required to maintain high energy efficiency while operating at the lowest possible load, placing new demands on both the system and its operation. Therefore, providing a CHP system with high economic efficiency, high energy utilization, and high electrical load regulation capability is a key technical problem that this invention aims to solve.

[0004] For example, the invention disclosed in patent application CN112855293B is an integrated thermal storage industrial steam supply cogeneration frequency regulation system. The system's heating steam includes steam extracted from the cold and hot sections of the heater and steam generated in the steam generator; these three components work together to meet the demands of the steam heating network. By adjusting the opening of the steam extraction regulating valves in the cold and hot sections of the heater and the speed of the feedwater pump in the water tank, molten salt thermal storage is used to assist the coal-fired power generation system in rapidly increasing and decreasing load, improving the unit's operational flexibility. However, in the frequency regulation system described in this application, the thermal and power regulation range is limited, and the peak-shaving and frequency regulation capabilities between coal-fired power generation and heating supply are limited. It is difficult to ensure economic efficiency while simultaneously regulating the load's thermal and power output, and the system's operational flexibility is relatively low. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings in the prior art and to provide a combined heat and power system and peak-shaving operation method with an integrated steam ejector that utilizes the mutual coupling of a steam ejector, an auxiliary heating network heater and a steam cooler to achieve efficient and flexible functions, has a high electrical load regulation capability and resource utilization rate, and maximizes its economy while meeting the electrical and thermal load requirements.

[0006] This invention discloses a combined heat and power (CHP) system with an integrated steam ejector and a peak-shaving operation method. The CHP system with the integrated steam ejector includes a coal-fired boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a steam cooler, a high-pressure regenerative heater, and further includes a low-pressure regenerative heater, a deaerator, a steam ejector, a main heat heater, and an auxiliary heat network heater, wherein:

[0007] The main steam outlet of the coal-fired boiler is connected to the inlet of the high-pressure cylinder and the inlet of the second control valve via control valve one; the steam extraction port of the high-pressure cylinder is connected to the hot end of the high-pressure regenerative heater, and the outlet of the high-pressure cylinder is connected to the reheat steam inlet of the coal-fired boiler and the inlet of the second control valve via control valve three.

[0008] The reheat steam outlet of the coal-fired boiler is connected to the inlet of the control valve two and the inlet of the intermediate pressure cylinder via control valve four; the steam extraction port of the intermediate pressure cylinder is connected to the hot end inlet of the deaerator; and the outlet of the intermediate pressure cylinder is connected to the main heating network heater and the low-pressure cylinder via control valve five.

[0009] The steam extraction port of the low-pressure cylinder is connected to the hot end inlet of the low-pressure regenerative heater, and the outlet of the low-pressure cylinder is connected to the low-pressure steam inlet of the steam ejector and the cold end inlet of the low-pressure regenerative heater respectively through control valve six.

[0010] The cold end outlet of the low-pressure regenerative heater is connected to the deaerator, the deaerator is connected to the cold end inlet of the high-pressure regenerative heater, the cold end outlet of the high-pressure regenerative heater is connected to the inlet of the coal-fired boiler and the cold end inlet of the steam cooler respectively through control valve seven, and the cold end outlet of the steam cooler is connected to the inlet of the coal-fired boiler.

[0011] The second outlet of the control valve is connected to the hot end inlet of the steam cooler and the high-pressure steam inlet of the steam ejector, respectively.

[0012] The mixed steam outlet of the steam ejector is connected to the hot end inlet of the main heating network heater and the hot end inlet of the auxiliary heating network heater via the control valve eight; the heating network water supply pipeline connects the heating network return water to the cold end inlet of the auxiliary heating network heater and the cold end inlet of the main heating network heater via the control valve nine; the cold end outlet of the auxiliary heating network heater is connected to the cold end inlet of the main heating network heater.

[0013] The cold end outlet of the main heating network heater is connected to the heating network water supply pipeline.

[0014] The optimized configuration also includes a condenser and a condensate pump, which are sequentially installed between the control valve six and the cold end inlet of the low-pressure regenerative heater.

[0015] The optimization also includes a feedwater pump, which is installed between the deaerator and the cold end inlet of the high-pressure regenerative heater.

[0016] A method for peak-shaving operation of a cogeneration system with an integrated steam ejector, comprising the following steps:

[0017] S1. After obtaining the heat and power load demand, determine in sequence whether it is within the heat and power regulation range of operating mode 1, operating mode 2, operating mode 3, operating mode 4, and operating mode 5, and prioritize the operation of the operating mode with the smaller serial number to ensure its economy while meeting the heat and power load demand.

[0018] S2. When the demand for heat supply and power generation is within the range of operating mode one, operating mode one shall be given priority: by the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam cooler, the steam ejector and the auxiliary heating network heater shall not be put into operation, and the heat source of the main heating network heater shall be the exhaust steam of the intermediate pressure cylinder. At this time, the economy is the highest while meeting the demand for heat and power load.

[0019] S3. When the power supply and heat demand are not within the range of operating mode one, operating mode two shall be adopted first: through the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam cooler, the steam ejector and the auxiliary heating network heater shall all be put into operation. The heat source of the auxiliary heating network heater is the mixed steam at the outlet of the steam ejector, and the heat source of the main heating network heater is the exhaust steam of the intermediate pressure cylinder.

[0020] S4. When the power supply and heat demand are not within the range of operating mode two, operating mode three shall be adopted first: through the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam ejector and the auxiliary heating network heater shall be put into operation, while the steam cooler shall not be put into operation. The heat source of the auxiliary heating network heater is the mixed steam at the outlet of the steam ejector, and the heat source of the main heating network heater is the exhaust steam of the intermediate pressure cylinder.

[0021] S5. When the power supply and heat demand are not within the range of operating mode three, operating mode four shall be adopted first: through the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam cooler and the steam ejector shall be put into operation, the auxiliary heating network heater shall not be put into operation, and the heat source of the main heating network heater shall be the exhaust steam of the intermediate pressure cylinder and the mixed steam of the outlet of the steam ejector;

[0022] S6. When the power supply and heat demand are not within the range of operating mode four, operating mode five is adopted: through the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam ejector is put into operation, the steam cooler and the auxiliary heating network heater are not put into operation, and the heat source of the main heating network heater is the exhaust steam of the intermediate pressure cylinder and the mixed steam of the outlet of the steam ejector.

[0023] In the optimized configuration, the high-pressure steam source of the steam ejector and the hot-end steam source of the steam cooler are either a single extraction steam source or an arbitrary mixture of steam from three extraction points: the main steam of the coal-fired boiler controlled by control valve one, the high-pressure steam of the high-pressure cylinder controlled by control valve three, and the reheat steam of the coal-fired boiler controlled by control valve four.

[0024] In the optimized mode of operation of the auxiliary heating network heater, the heating network water can be connected in parallel with the pipeline and the auxiliary heating network heater or all the heating network water can be operated through the auxiliary heating network heater by adjusting the two outlets of the control valve.

[0025] Optimized, the outlet pressure of the steam ejector can be higher than, equal to, or lower than the outlet pressure of control valve five; when the outlet pressure of the steam ejector is higher than or equal to the outlet pressure of control valve five, the flow rate of mixed steam entering the main heating network heater and the auxiliary heating network heater can be adjusted by adjusting the outlet of control valve eight; when the outlet pressure of the steam ejector is lower than the outlet pressure of control valve five, the mixed steam from the steam ejector can be fully introduced into the auxiliary heating network heater by adjusting the outlet of control valve eight.

[0026] In an optimized configuration, when the steam cooler is in operation, the feedwater from the coal-fired boiler can be connected in parallel with the steam cooler via the adjustment of the two outlets of the control valve, or all feedwater can pass through the steam cooler.

[0027] In optimized operation mode one, control valve two is in a closed state, the connection interface between control valve seven and the cold end inlet of the steam cooler is in a closed state, the connection interface between control valve six and the low-pressure steam inlet of the steam ejector is in a closed state, control valve eight is in a closed state, and the connection interface between control valve nine and the cold end inlet of the auxiliary heating network heater is in a closed state. In operation mode two, the connection interface between control valve eight and the hot end inlet of the main heating network heater is in a closed state. In operation mode three, the connection interface between control valve eight and the hot end of the main heating network heater is in a closed state, and the connection interfaces between control valve two and control valve seven and the hot end inlet and cold end inlet of the steam cooler, respectively, are in a closed state.

[0028] To optimize and achieve operating mode four, the connection between control valve nine and the cold inlet of the auxiliary heating network heater is closed, and the connection between control valve eight and the hot inlet of the auxiliary heating network heater is closed. To achieve operating mode five, the connection between control valve two and the high-pressure steam inlet of the steam cooler is closed, the connection between control valve seven and the cold inlet of the steam cooler is closed, the connection between control valve eight and the hot inlet of the auxiliary heating network heater is closed, and the connection between control valve nine and the cold inlet of the auxiliary heating network heater is closed.

[0029] In a combined heat and power (CHP) system with integrated steam ejectors, the heat and power load demand refers to the system's demand for both heat and electricity. Heat load demand refers to the system's need for heat energy, including heating and hot water supply; electricity load demand refers to the system's need for electricity, including lighting, power equipment operation, and production process requirements. A coal-fired CHP system is a coal-fired energy utilization system that simultaneously provides heating and power generation. Existing coal-fired CHP units are mainly derived from existing CHP unit designs and heating retrofits of pure condensing units. Currently, their heating methods primarily include extraction steam heating and high back pressure heating. In a CHP system, the heat and power load demand is dynamic and influenced by various factors such as weather, season, and lifestyle habits. Therefore, the system needs to be adjusted in real time according to changes in load demand to ensure the system's economic efficiency and stability. However, current understanding of the structural and functional shortcomings of coal-fired CHP systems reveals several areas for improvement.

[0030] Low efficiency of steam ejectors: In cogeneration systems with integrated steam ejectors, the efficiency of the steam ejectors is usually low, which leads to a reduction in the efficiency of the entire system.

[0031] Steam ejectors are prone to clogging and wear: Steam ejectors operate in a high-temperature and high-pressure environment, making them susceptible to clogging and wear, which affects the stability and lifespan of the system.

[0032] Low system power: Currently available integrated steam ejector cogeneration systems have low power, which cannot meet the application scenarios with high power requirements;

[0033] Low system efficiency: Due to structural and functional limitations, the cogeneration systems with integrated steam ejectors currently on the market have relatively low efficiency and cannot meet the requirements for high-efficiency operation.

[0034] Poor system stability: Cogeneration systems with integrated steam ejectors are prone to fluctuations and instability during operation, which affects the system's performance and lifespan.

[0035] The beneficial effects of the integrated steam ejector cogeneration system described in this invention are as follows:

[0036] Improved efficiency of the steam ejector: The high-pressure steam source of the steam ejector in this system includes the main steam of the coal-fired boiler, the high-pressure steam of the high-pressure cylinder, and the reheat steam of the coal-fired boiler, or a mixture of steam from a single extraction point or three extraction points. The mixed steam at the outlet of the steam ejector includes a single source or a mixture of both the auxiliary heating network heater hot end inlet and the main heating network heater hot end inlet. In different operating modes, the application state of the steam ejector under different thermoelectric regulation range requirements can be changed by adjusting the control valve, thereby improving the efficiency of the steam ejector.

[0037] To address the common issues of clogging and wear in steam ejectors, the system offers five operating modes. Except for the first mode, the other four modes all involve the operation of the steam ejector. To prevent the steam ejector from operating under high temperature and high pressure conditions for extended periods, the system effectively mitigates potential clogging and wear issues by switching between different operating modes under the same thermoelectric regulation range.

[0038] To improve system efficiency and stability: The five operating modes each have their own load adjustment range. After obtaining the heat and power load demand, it is determined in sequence whether it falls within the heat and power adjustment range of operating mode one, operating mode two, operating mode three, operating mode four, and operating mode five. The operating mode with the smaller serial number is given priority to operate, ensuring its economy while meeting the heat and power load demand.

[0039] Compared with existing technologies, this system utilizes the coupling of steam ejectors, auxiliary heating network heaters, and steam coolers, along with corresponding operational adjustment techniques, to achieve efficient and flexible energy supply. Five operating modes each have their own load adjustment range. Operating mode one is the original unit operating mode, where the steam ejector, auxiliary heating network heater, and steam ejector are not in operation. Operating mode two utilizes the steam ejector to recover waste steam for heating; the pressure of the mixed steam is lower than the original heating extraction steam, and it is used as a heat source for the auxiliary heating network heaters to heat the heating network water. Operating mode three, compared to operating mode two, mainly eliminates the process of the main steam entering the steam cooler before entering the ejector, thus reducing power generation but achieving greater heating capacity. Operating mode four, compared to operating mode two, has the same mixed steam pressure as the original heating extraction steam, but the ejector ratio is lower than in operating mode two. Under the same thermal and power load, the waste steam recovery rate is lower than in operating mode two, but the lower power generation limit of operating mode four is more favorable for low-load operation of the unit. Compared to other operating modes, operating mode five primarily eliminates the need for the main steam to enter the steam cooler before reaching the ejector, thus achieving greater heating capacity and a lower power generation threshold. Furthermore, if several modes can meet the demands of a given thermal power load, the operating mode with the lower serial number will have the lowest energy consumption. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a combined heat and power system with an integrated steam ejector and a peak-shaving operation method according to the present invention.

[0041] Figure 2 This is a schematic diagram of the peak-shaving operation method of a cogeneration system with an integrated steam ejector according to the present invention.

[0042] Figure 3 This invention relates to the adjustment range of a combined heat and power system with an integrated steam ejector in different modes.

[0043] The attached diagram shows: 1: Coal-fired boiler, 2: Control valve 4, 3: Control valve 1, 4: Control valve 3, 5: High-pressure cylinder, 6: Medium-pressure cylinder, 7: Control valve 5, 8: Low-pressure cylinder, 9: Generator, 10: Steam cooler, 11: Control valve 2, 12: Deaerator, 13: Control valve 6, 14: Condenser, 15: Control valve 7, 16: High-pressure regenerative heater, 17: Feedwater pump, 18: Low-pressure regenerative heater, 19: Condensate pump, 20: Steam ejector, 21: Control valve 8, 22: Main heating network heater, 23: Auxiliary heating network heater, 24: Control valve 9. Implementation

[0044] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other. Example

[0047] The embodiments of the present invention relate to a combined heat and power system with an integrated steam ejector and a peak-shaving operation method. The combined heat and power system with the integrated steam ejector is as follows: Figure 1 As shown, it includes a coal-fired boiler 1, a high-pressure cylinder 5, a medium-pressure cylinder 6, a low-pressure cylinder 8, a steam cooler 10, a high-pressure regenerative heater 16, and also includes a low-pressure regenerative heater 18, a deaerator 12, a steam ejector 20, a main heat heater, and an auxiliary heat network heater 23.

[0048] The main steam outlet of the coal-fired boiler 1 is connected to the inlet of the high-pressure cylinder 5 and the inlet of the control valve 11 via control valve 3. The extraction port of the high-pressure cylinder 5 is connected to the hot end of the high-pressure regenerative heater 16, and the outlet of the high-pressure cylinder 5 is connected to the reheat steam inlet of the coal-fired boiler 1 and the inlet of the control valve 11 via control valve 4. During this process, the main steam of the coal-fired boiler 1 is released and recovered into the reheat steam inlet of the coal-fired boiler 1 via the high-pressure cylinder 5. This further increases the steam temperature and pressure, improves steam quality and thermal efficiency, reduces moisture and impurities in the steam, reduces corrosion and scaling on the equipment, and makes the steam output more stable and reliable. The main steam of the coal-fired boiler 1 enters the steam ejector 20 and the steam cooler 10 through the regulation of control valve 11. The main steam entering the steam ejector 20 helps reduce the consumption of main steam and improves the thermal efficiency of the coal-fired boiler 1; the main steam entering the steam cooler 10 reduces moisture and impurities in the steam, improving the purity and dryness of the steam.

[0049] The reheat steam outlet of the coal-fired boiler 1 is connected to the inlet of the control valve 11 and the inlet of the intermediate pressure cylinder 6 via control valve 4 2 respectively; the steam extraction port of the intermediate pressure cylinder 6 is connected to the hot end inlet of the deaerator 12, and the outlet of the intermediate pressure cylinder 6 is connected to the main heating network heater 22 and the low pressure cylinder 8 via control valve 5 7 respectively.

[0050] The steam extraction port of the low-pressure cylinder 8 is connected to the hot end inlet of the low-pressure regenerative heater 18. The outlet of the low-pressure cylinder 8 is connected to the low-pressure steam inlet of the steam ejector 20 and the cold end inlet of the low-pressure regenerative heater 18 via control valve 13. A condenser 14 and a condensate pump 19 are installed sequentially between control valve 13 and the cold end inlet of the low-pressure regenerative heater 18. The steam discharged from the low-pressure cylinder 8 is recovered by the condenser 14 and the condensate pump 19, condensed into water, and the condensate is transported back to the inlet of the coal-fired boiler 1, reducing the soft water supply to the coal-fired boiler 1. At the same time, because the temperature of the recovered condensate is relatively high, the feedwater temperature of the coal-fired boiler is increased, thereby reducing fuel consumption and production costs.

[0051] The cold end outlet of the low-pressure regenerative heater 18 is connected to the deaerator 12, the deaerator 12 is connected to the cold end inlet of the high-pressure regenerative heater 16, a feed water pump 17 is installed between the deaerator 12 and the cold end inlet of the high-pressure regenerative heater 16, the cold end outlet of the high-pressure regenerative heater 16 is connected to the inlet of the coal-fired boiler 1 and the cold end inlet of the steam cooler 10 respectively through control valve 7 15, and the cold end outlet of the steam cooler 10 is connected to the inlet of the coal-fired boiler 1.

[0052] The outlet of the control valve 11 is connected to the hot end inlet of the steam cooler 10 and the high-pressure steam inlet of the steam ejector 20, respectively.

[0053] The mixed steam outlet of the steam ejector 20 is connected to the hot end inlet of the main heating network heater 22 and the hot end inlet of the auxiliary heating network heater 23 via the control valve 8 21; the heating network water supply pipeline connects the heating network return water to the cold end inlet of the auxiliary heating network heater 23 and the cold end inlet of the main heating network heater 22 via the control valve 9 24; the cold end outlet of the auxiliary heating network heater 23 is connected to the cold end inlet of the main heating network heater 22; and the cold end outlet of the main heating network heater 22 is connected to the heating network water supply pipeline.

[0054] In the aforementioned connection, the extracted steam from the low-pressure cylinder 8, intermediate-pressure cylinder 6, and high-pressure cylinder 5 ultimately returns to the coal-fired boiler 1. This primarily utilizes the energy of this steam to improve the overall thermal efficiency of the system. Specifically, the extracted steam from the low-pressure cylinder 8 returns to the heater, participating in the heating process and increasing the temperature and pressure of the steam entering the high-pressure cylinder 5; the extracted steam from the intermediate-pressure cylinder 6 returns to the heater, further participating in the heating process and further increasing the temperature and pressure of the steam entering the high-pressure cylinder 5; and the extracted steam from the high-pressure cylinder 5 returns to the main steam pipe of the coal-fired boiler 1, participating in the energy conversion process and improving its thermal efficiency. Furthermore, the return of extracted steam to the coal-fired boiler 1 achieves tiered energy utilization, utilizing steam at different pressure levels to perform work and maximizing energy utilization. Simultaneously, the return of extracted steam to the coal-fired boiler 1 also reduces other energy consumption, such as electricity consumption, further improving the economy and environmental friendliness of the entire thermal system.

[0055] An auxiliary heating network heater 23 is installed in front of the main heating network heater 22. The operation of the auxiliary heating network heater 23 provides preheating for the main heating network heater 22, enabling it to reach its optimal working state more quickly. This effectively improves the thermal efficiency of the entire thermal system, reduces energy consumption and operating costs, and is more economical. At the same time, it shares some of the burden, reduces wear and tear on the main heating network heater 22, extends its service life, and reduces operating costs.

[0056] At the inlet of the coal-fired boiler 1, the operation of the steam cooler 10 can recover the heat of the steam, improve energy utilization efficiency, improve the thermal efficiency of the thermal system, and reduce the temperature at the boiler inlet, protecting the safety of the boiler and the entire thermal system, extending the service life of the boiler and related equipment, and reducing maintenance costs. However, if the steam cooler 10 is not in operation, the heat of the steam may not be recovered, the thermal efficiency will be relatively low, the temperature at the boiler inlet may be too high, posing potential safety risks to the equipment and system, and the wear and tear of related equipment may increase, and maintenance costs may increase accordingly.

[0057] The peak-shaving operation method in this embodiment includes the following steps:

[0058] S1. After obtaining the heat and power load demand, determine in sequence whether it is within the heat and power regulation range of operating mode 1, operating mode 2, operating mode 3, operating mode 4, and operating mode 5, and prioritize the operation of the operating mode with the smaller serial number to ensure its economy while meeting the heat and power load demand.

[0059] S2. When the demand for heat supply and power generation is within the range of operating mode one, operating mode one shall be given priority: by the joint adjustment of control valve 1 3, control valve 2 11, control valve 3 4, control valve 4 2, control valve 5 7, control valve 6 13, control valve 7 15, control valve 8 21, and control valve 9 24, the steam cooler 10, the steam ejector 20, and the auxiliary heat network heater 23 shall not be put into operation, and the heat source of the main heat network heater 22 shall be the exhaust steam of the intermediate pressure cylinder 6. At this time, the economy is the highest while meeting the demand for heat and power load.

[0060] S3. When the power supply and heat generation requirements are not within the range of operating mode one, operating mode two shall be adopted first: through the joint adjustment of control valve 1 3, control valve 2 11, control valve 3 4, control valve 4 2, control valve 5 7, control valve 6 13, control valve 7 15, control valve 8 21, and control valve 9 24, the steam cooler 10, the steam ejector 20, and the auxiliary heating network heater 23 shall all be put into operation. The heat source of the auxiliary heating network heater 23 is the mixed steam at the outlet of the steam ejector 20, and the heat source of the main heating network heater 22 is the exhaust steam from the intermediate pressure cylinder 6.

[0061] S4. When the power supply and heat generation requirements are not within the range of operating mode two, operating mode three shall be adopted first: through the joint adjustment of control valve 1 3, control valve 2 11, control valve 3 4, control valve 4 2, control valve 5 7, control valve 6 13, control valve 7 15, control valve 8 21, and control valve 9 24, the steam ejector 20 and the auxiliary heating network heater 23 shall be put into operation, while the steam cooler 10 shall not be put into operation. The heat source of the auxiliary heating network heater 23 is the mixed steam at the outlet of the steam ejector 20, and the heat source of the main heating network heater 22 is the exhaust steam from the intermediate pressure cylinder 6.

[0062] S5. When the power supply and heat generation requirements are not within the range of operating mode three, operating mode four shall be adopted first: through the joint adjustment of control valve 1 3, control valve 2 11, control valve 3 4, control valve 4 2, control valve 5 7, control valve 6 13, control valve 7 15, control valve 8 21, and control valve 9 24, the steam cooler 10 and the steam ejector 20 shall be put into operation, the auxiliary heating network heater 23 shall be put into operation, and the heat source of the main heating network heater 22 shall be the exhaust steam of the intermediate pressure cylinder 6 and the outlet steam of the steam ejector 20.

[0063] S6. When the power supply and heat demand are not within the range of operating mode four, operating mode five is adopted: through the joint adjustment of control valve 1 3, control valve 2 11, control valve 3 4, control valve 4 2, control valve 5 7, control valve 6 13, control valve 7 15, control valve 8 21, and control valve 9 24, the steam ejector 20 is put into operation, the steam cooler 10 and the auxiliary heating network heater 23 are not put into operation, and the heat source of the main heating network heater 22 is the exhaust steam of the intermediate pressure cylinder 6 and the mixed steam at the outlet of the steam ejector 20.

[0064] The high-pressure steam source of the steam ejector 20 and the hot-end steam source of the steam cooler 10 are either the main steam of the coal-fired boiler 1 controlled by the control valve 3, the high-pressure steam of the high-pressure cylinder 5 controlled by the control valve 4, or the reheat steam of the coal-fired boiler 1 controlled by the control valve 2, or a mixture of steam from a single extraction point or steam from three extraction points.

[0065] In the mode where the auxiliary heating network heater 23 is in operation, the heating network water can be connected in parallel with the pipeline and the auxiliary heating network heater 23 or all the heating network water can be run through the auxiliary heating network heater 23 by adjusting the two outlets of the control valve 24.

[0066] The outlet pressure of the steam ejector 20 can be higher than, equal to or lower than the outlet pressure of the control valve 7. When the outlet pressure of the steam ejector 20 is higher than or equal to the outlet pressure of the control valve 7, the flow rate of the mixed steam entering the main heating network heater 22 and the auxiliary heating network heater 23 can be adjusted by adjusting the outlet of the control valve 21. When the outlet pressure of the steam ejector 20 is lower than the outlet pressure of the control valve 7, the mixed steam of the steam ejector 20 can be completely introduced into the auxiliary heating network heater 23 by adjusting the outlet of the control valve 21.

[0067] When the steam cooler 10 is in operation, the feedwater of the coal-fired boiler 1 can be connected in parallel with the steam cooler 10 through the adjustment of the two outlets of the control valve 15, or all the feedwater can be supplied through the steam cooler 10.

[0068] To achieve operating mode one, control valve two 11 is in the closed state, the connection interface between control valve seven 15 and the cold end inlet of the steam cooler 10 is in the closed state, the connection interface between control valve six 13 and the low-pressure steam inlet of the steam ejector 20 is in the closed state, control valve eight 21 is in the closed state, the connection interface between control valve nine 24 and the cold end inlet of the auxiliary heating network heater 23 is in the closed state, and the others are in the connected state.

[0069] To achieve operating mode two, the connection interface between control valve 8 21 and the hot end inlet of the main heating network heater 22 is in the closed state, while the others are in the connected state.

[0070] To achieve operating mode three, the connection interface between control valve eight 21 and the hot end inlet of the main heating network heater 22 is in the closed state, the connection interfaces between control valve two 11 and control valve seven 15 and the hot end inlet and cold end inlet of the steam cooler 10 are in the closed state, and the others are in the connected state.

[0071] To achieve operating mode four, the connection interface between control valve nine 24 and the cold end inlet of the auxiliary heating network heater 23 is closed, the connection interface between control valve eight 21 and the hot end inlet of the auxiliary heating network heater 23 is closed, and the others are in a connected state.

[0072] To achieve operating mode five, the connection interface between control valve 2 11 and the high-pressure steam inlet of the steam cooler 10 is in a closed state; the connection interface between control valve 7 15 and the cold end inlet of the steam cooler 10 is in a closed state; the connection interface between control valve 8 21 and the hot end inlet of the auxiliary heating network heater 23 is in a closed state; the connection interface between control valve 9 24 and the cold end inlet of the auxiliary heating network heater 23 is in a closed state; and all others are in a connected state.

[0073] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A combined heat and power system with an integrated steam ejector, comprising a coal-fired boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a steam cooler, and a high-pressure regenerative heater, characterized in that, It also includes a low-pressure regenerative heater, a deaerator, a steam ejector, a main heat heater, and an auxiliary heat network heater, wherein: The main steam outlet of the coal-fired boiler is connected to the inlet of the high-pressure cylinder and the inlet of the second control valve via control valve one; the steam extraction port of the high-pressure cylinder is connected to the hot end of the high-pressure regenerative heater, and the outlet of the high-pressure cylinder is connected to the reheat steam inlet of the coal-fired boiler and the inlet of the second control valve via control valve three. The reheat steam outlet of the coal-fired boiler is connected to the inlet of the control valve two and the inlet of the intermediate pressure cylinder via control valve four; the steam extraction port of the intermediate pressure cylinder is connected to the hot end inlet of the deaerator; and the outlet of the intermediate pressure cylinder is connected to the main heating network heater and the low-pressure cylinder via control valve five. The steam extraction port of the low-pressure cylinder is connected to the hot end inlet of the low-pressure regenerative heater, and the outlet of the low-pressure cylinder is connected to the low-pressure steam inlet of the steam ejector and the cold end inlet of the low-pressure regenerative heater respectively through control valve six. The cold end outlet of the low-pressure regenerative heater is connected to the deaerator, the deaerator is connected to the cold end inlet of the high-pressure regenerative heater, the cold end outlet of the high-pressure regenerative heater is connected to the inlet of the coal-fired boiler and the cold end inlet of the steam cooler respectively through control valve seven, and the cold end outlet of the steam cooler is connected to the inlet of the coal-fired boiler. The second outlet of the control valve is connected to the hot end inlet of the steam cooler and the high-pressure steam inlet of the steam ejector, respectively. The mixed steam outlet of the steam ejector is connected to the hot end inlet of the main heating network heater and the hot end inlet of the auxiliary heating network heater via control valve eight; the heating network water supply pipeline connects the heating network return water to the cold end inlet of the auxiliary heating network heater and the cold end inlet of the main heating network heater via control valve nine; the cold end outlet of the auxiliary heating network heater is connected to the cold end inlet of the main heating network heater. The cold end outlet of the main heating network heater is connected to the heating network water supply pipeline.

2. A cogeneration system with an integrated steam ejector according to claim 1, characterized in that, It also includes a condenser and a condensate pump, wherein the condenser and the condensate pump are sequentially installed between the control valve and the cold end inlet of the low-pressure regenerative heater.

3. A combined heat and power system with an integrated steam ejector according to claim 1, characterized in that, It also includes a water pump, which is installed between the deaerator and the cold end inlet of the high-pressure regenerative heater.

4. A peak-shaving operation method for a cogeneration system with an integrated steam ejector according to any one of claims 1-3, characterized in that, The steps of the peak-shaving operation method are as follows: S1. After obtaining the heat and power load demand, determine in sequence whether it is within the heat and power regulation range of operating mode 1, operating mode 2, operating mode 3, operating mode 4, and operating mode 5, and prioritize the operation of the operating mode with the smaller serial number to ensure its economy while meeting the heat and power load demand. S2. When the demand for heat supply and power generation is within the range of operating mode one, operating mode one shall be given priority: by the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam cooler, the steam ejector and the auxiliary heating network heater shall not be put into operation, and the heat source of the main heating network heater shall be the exhaust steam of the intermediate pressure cylinder. At this time, the economy is the highest while meeting the demand for heat and power load. S3. When the power supply and heat demand are not within the range of operating mode one, operating mode two shall be adopted first: through the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam cooler, the steam ejector and the auxiliary heating network heater shall all be put into operation. The heat source of the auxiliary heating network heater is the mixed steam at the outlet of the steam ejector, and the heat source of the main heating network heater is the exhaust steam of the intermediate pressure cylinder. S4. When the power supply and heat demand are not within the range of operating mode two, operating mode three shall be adopted first: through the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam ejector and the auxiliary heating network heater shall be put into operation, while the steam cooler shall not be put into operation. The heat source of the auxiliary heating network heater is the mixed steam at the outlet of the steam ejector, and the heat source of the main heating network heater is the exhaust steam of the intermediate pressure cylinder. S5. When the power supply and heat demand are not within the range of operating mode three, operating mode four shall be adopted first: through the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam cooler and the steam ejector shall be put into operation, the auxiliary heating network heater shall not be put into operation, and the heat source of the main heating network heater shall be the exhaust steam of the intermediate pressure cylinder and the mixed steam of the outlet of the steam ejector; S6. When the power supply and heat demand are not within the range of operating mode four, operating mode five is adopted: through the joint adjustment of control valve one, control valve two, control valve three, control valve four, control valve five, control valve six, control valve seven, control valve eight and control valve nine, the steam ejector is put into operation, the steam cooler and the auxiliary heating network heater are not put into operation, and the heat source of the main heating network heater is the exhaust steam of the intermediate pressure cylinder and the mixed steam of the outlet of the steam ejector.

5. A peak-shaving operation method for a cogeneration system with an integrated steam ejector as described in claim 4, characterized in that, The high-pressure steam source of the steam ejector and the hot-end steam source of the steam cooler are both the main steam of the coal-fired boiler controlled by control valve one, the high-pressure steam of the high-pressure cylinder controlled by control valve three, and the reheat steam of the coal-fired boiler controlled by control valve four, or a mixture of steam from a single extraction point or steam from three extraction points.

6. A peak-shaving operation method for a cogeneration system with an integrated steam ejector according to claim 4, characterized in that, In the operation mode of the auxiliary heating network heater, the heating network water can be connected in parallel with the pipeline and the auxiliary heating network heater or all the heating network water can be run through the auxiliary heating network heater by adjusting the two outlets of the control valve.

7. A peak-shaving operation method for a cogeneration system with an integrated steam ejector according to claim 4, characterized in that, The outlet pressure of the steam ejector can be higher than, equal to or lower than the outlet pressure of control valve five; when the outlet pressure of the steam ejector is higher than or equal to the outlet pressure of control valve five, the flow rate of mixed steam entering the main heating network heater and the auxiliary heating network heater is adjusted by adjusting the outlet of control valve eight; when the outlet pressure of the steam ejector is lower than the outlet pressure of control valve five, the outlet of control valve eight is adjusted so that all the mixed steam from the steam ejector enters the auxiliary heating network heater.

8. A peak-shaving operation method for a cogeneration system with an integrated steam ejector as described in claim 7, characterized in that, When the steam cooler is in operation, the feedwater from the coal-fired boiler can be connected in parallel with the steam cooler through the adjustment of the two outlets of the control valve, or all the feedwater can pass through the steam cooler.

9. A peak-shaving operation method for a cogeneration system with an integrated steam ejector as described in claim 4, characterized in that: To achieve operating mode one, control valve two is in the off state, the connection interface between control valve seven and the cold end inlet of the steam cooler is in the off state, the connection interface between control valve six and the low-pressure steam inlet of the steam ejector is in the off state, control valve eight is in the off state, and the connection interface between control valve nine and the cold end inlet of the auxiliary heating network heater is in the off state. To achieve operating mode two, the connection interface between control valve eight and the hot end inlet of the main heating network heater is in the off state. To achieve operating mode three, the connection interface between control valve eight and the hot end inlet of the main heating network heater is in the off state, and the connection interfaces between control valve two and control valve seven and the hot end inlet and cold end inlet of the steam cooler, respectively, are in the off state.

10. A peak-shaving operation method for a cogeneration system with an integrated steam ejector according to claim 4, characterized in that: To achieve operating mode four, the connection between control valve nine and the cold end inlet of the auxiliary heating network heater is closed, and the connection between control valve eight and the hot end inlet of the auxiliary heating network heater is closed. To achieve operating mode five, the connection between control valve two and the high-pressure steam inlet of the steam cooler is closed, the connection between control valve seven and the cold end of the steam cooler is closed, the connection between control valve eight and the hot end of the auxiliary heating network heater is closed, and the connection between control valve nine and the cold end inlet of the auxiliary heating network heater is closed.

Images