A multi-stage gas turbine waste heat recovery system based on heat pump coupling

Abstract

The utility model discloses a kind of multistage gas turbine waste heat recovery systems based on heat pump coupling, belong to comprehensive energy system technical field, including gas turbine and user terminal, the exhaust end of the gas turbine is connected with three-stage waste heat recovery assembly, the output end of the three-stage waste heat recovery assembly is connected with the user terminal through steam pipeline, the output end of the gas turbine is connected with multi-energy complementary energy module, the multi-energy complementary energy module is connected with the three-stage waste heat recovery assembly, the user terminal respectively through power transmission line connection.The utility model effectively improves comprehensive thermal efficiency by flue gas full-temperature section cascade recovery, combined with solar energy preferential power supply and thermal decoupling design, solve the problem that traditional heat pump relies on power grid, unstable operation, significantly reduce energy consumption and pollution.

Description

Technical Field

[0001] This utility model relates to the field of integrated energy system technology, and in particular to a multi-stage gas turbine waste heat recovery system based on heat pump coupling. Background Technology

[0002] Gas turbines, with their high efficiency and flexibility, have become an indispensable core piece of equipment in the energy transition. However, during operation, a significant amount of waste heat is emitted as high-temperature flue gas, resulting in energy waste. Simultaneously, combined heat and power (CHP) or combined cooling, heating, and power (CCHP) systems frequently face thermoelectric coupling problems, leading to system instability. Heat pump technology can not only efficiently recover low- and medium-grade waste heat, converting it into energy for heating, cooling, or power generation, but also expand the system's feasible operating range and achieve thermoelectric decoupling. Therefore, gas turbine systems coupled with heat pump technology have become a research hotspot.

[0003] In the prior art, invention patent CN119737230A, entitled "A Gas Turbine System Coupled with a High-Temperature Heat Pump and Energy Storage and Its Operation Method," discloses a gas turbine system that coordinates a heat pump and energy storage. In this system, the waste heat of the gas turbine is transferred to the high-temperature heat pump, and waste heat loss is reduced through the cascade utilization of thermal energy. However, the compressor operation of the high-temperature heat pump system relies on the power grid or other external energy input. This system does not consider the energy consumption of the heat pump, resulting in insufficient system stability and increased operating costs during periods of high electricity prices.

[0004] To address the aforementioned shortcomings, a multi-energy complementary multi-stage gas turbine waste heat recovery system based on heat pump coupling is proposed. Utility Model Content

[0005] The purpose of this invention is to provide a multi-stage gas turbine waste heat recovery system based on heat pump coupling to solve the problems in the background art.

[0006] To achieve the above objectives, this utility model provides a multi-stage gas turbine waste heat recovery system based on heat pump coupling, including a gas turbine and a user terminal. The exhaust end of the gas turbine is connected to a three-stage waste heat recovery assembly. The output end of the three-stage waste heat recovery assembly is connected to the user terminal through a steam pipe. The output end of the gas turbine is connected to a multi-energy complementary energy module. The multi-energy complementary energy module is connected to the three-stage waste heat recovery assembly and the user terminal respectively through power transmission lines.

[0007] Preferably, the three-stage waste heat recovery assembly includes a flue connected to the exhaust end of the gas turbine and a waste heat boiler, a conventional high-temperature heat pump, and a cascade high-temperature heat pump sequentially arranged on the flue. The waste heat boiler, the conventional high-temperature heat pump, and the cascade high-temperature heat pump are all connected to the user terminal through the steam pipeline.

[0008] Preferably, the multi-energy complementary energy module includes a photovoltaic power generation unit, a power distribution unit, and an electrolysis hydrogen production unit. The output end of the photovoltaic power generation unit is connected to the power distribution unit and the electrolysis hydrogen production unit respectively through the power transmission line. The output end of the electrolysis hydrogen production unit is connected to the fuel inlet of the gas turbine through a hydrogen transmission pipeline and a hydrogen storage buffer unit.

[0009] Preferably, an energy storage unit is connected to the transmission line between the photovoltaic power generation unit and the power distribution unit.

[0010] Preferably, the power receiving end of the power distribution unit is connected to the output end of the gas turbine through the transmission line, and the power sending end of the power distribution unit is connected to the conventional high-temperature heat pump, the cascade high-temperature heat pump, and the user terminal through the transmission line respectively.

[0011] Preferably, the photovoltaic power generation unit is configured as a solar panel, the electrolysis hydrogen production unit is configured as an electrolyzer, the hydrogen storage buffer unit is configured as a high-pressure gas cylinder, the energy storage unit is configured as a battery energy storage system, and the power distribution unit is configured as a transformer.

[0012] Therefore, the multi-stage gas turbine waste heat recovery system based on heat pump coupling of the present invention, using the above-described structure, has the following beneficial effects:

[0013] (1) By implementing a three-stage waste heat recovery system covering the entire temperature range of the gas turbine flue gas, the overall thermal efficiency is significantly improved. The introduction of photovoltaic power generation, electrolysis hydrogen production, and energy storage units prioritizes solar energy to drive the heat pump compressor, and the energy storage unit regulates power supply and demand, completely resolving the high operating costs and insufficient stability issues caused by the reliance on grid power supply in traditional heat pumps. In industrial sectors (such as steel and chemical industries), high-temperature waste heat can be recovered for use in production processes; in the building sector, low-carbon heating / cooling can be achieved, comprehensively reducing energy costs and waste.

[0014] (2) Hydrogen is produced by electrolysis through photovoltaic power generation unit, and hydrogen is used to supplement gas turbine fuel through hydrogen storage buffer unit, forming a closed loop of solar energy-green electricity-green hydrogen-power generation; the power distribution unit integrates gas turbine power generation, photovoltaic power and energy storage power to supply power to waste heat recovery components and user terminals, directly embedding renewable energy into the core of the system, which not only reduces dependence on fossil energy, but also solves the problem of intermittency of renewable energy through multi-energy complementary architecture and improves the stability of energy supply; especially during periods of high electricity price, the energy storage unit realizes peak shifting and valley filling, ensuring the continuous operation of heat pump and avoiding the operation interruption of traditional system caused by external power fluctuations.

[0015] (3) The combination design of conventional and cascade high-temperature heat pumps breaks through the temperature limitation of a single heat pump. Its adjustable heat supply ratio can effectively broaden the output range of gas turbine power generation. When the heat demand is high and the power demand is low, the heat pump can absorb waste heat to produce steam, thus relieving the constraint of thermoelectric coupling on power generation. During peak power demand, the system prioritizes power supply to meet the grid peak shaving demand, adapting to the heat and power demand fluctuation scenarios of industrial parks, commercial buildings, etc. It not only supports peak shaving and valley filling when renewable energy is connected to the grid, but also improves the adaptability and reliability of the system under all operating conditions through thermoelectric decoupling optimization, solving the operational instability defects caused by thermoelectric coupling.

[0016] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model;

[0018] Figure 2 This is a schematic diagram of the three-stage waste heat recovery component according to an embodiment of the present invention;

[0019] Figure label:

[0020] 1. Gas turbine; 2. User terminal; 3. Three-stage waste heat recovery assembly; 31. Flue; 32. Waste heat boiler; 33. Conventional high-temperature heat pump; 34. Cascade high-temperature heat pump; 4. Steam pipeline; 5. Power transmission line; 6. Photovoltaic power generation unit; 7. Power distribution unit; 8. Electrolysis hydrogen production unit; 9. Hydrogen transmission pipeline; 10. Hydrogen storage buffer unit; 11. Energy storage unit. Detailed Implementation

[0021] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in this utility model shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] A gas turbine is an engine that uses the gas produced by the combustion of fuel to drive a turbine to generate mechanical work. Its conventional structure is as follows: Figure 2 As shown, first, air enters the compressor and is compressed. The compressed air then enters the combustion chamber, where the mixture of fuel (usually natural gas) and compressed air is ignited, producing high-temperature, high-pressure gas that enters the turbine. The turbine blades are thrust and rotate (exhaust gas is discharged). The rotation of the turbine drives the shaft connected to it to rotate, thereby transferring mechanical energy to the generator, and the generated electrical energy is transmitted to the power grid.

[0024] Example

[0025] like Figures 1-2 As shown, this utility model discloses a multi-stage gas turbine waste heat recovery system based on heat pump coupling, comprising a gas turbine 1, a three-stage waste heat recovery assembly 3, a multi-energy complementary energy module, and a user terminal 2. The flue gas discharged from the gas turbine 1 undergoes cascaded waste heat utilization through the three-stage waste heat recovery assembly 3, and the generated steam is transported to the user terminal 2 via a steam pipeline 4. The electrical energy generated by the gas turbine 1 is transported to the multi-energy complementary energy module via a transmission line 5. The multi-energy complementary energy module supplies power to the three-stage waste heat recovery assembly 3 and the user terminal 2, meeting their electricity needs.

[0026] The three-stage waste heat recovery assembly 3 includes a flue 31 connected to the exhaust end of the gas turbine 1 and a waste heat boiler 32, a conventional high-temperature heat pump 33, and a cascade high-temperature heat pump 34 arranged sequentially on the flue 31. The waste heat boiler 32, the conventional high-temperature heat pump 33, and the cascade high-temperature heat pump 34 are all connected to the user terminal 2 through a steam pipe 4. By combining the conventional and cascade heat pumps, the temperature limitation of a single heat pump can be overcome, and efficient utilization of low-temperature waste heat can be achieved.

[0027] In this embodiment, a small gas turbine regenerative cycle unit with a rated power of 865kW is selected as the power generation equipment of the energy station; a waste heat boiler 32 with a rated evaporation capacity of 1.6t / h is selected as the waste heat utilization equipment for the 275℃ high-temperature section of flue gas; a conventional high-temperature heat pump 33 with an energy efficiency ratio of 3.95 and a rated steam output of 0.55t / h is selected as the waste heat utilization equipment for the 120℃ medium-temperature section of flue gas; and a cascade high-temperature heat pump 34 with an energy efficiency ratio of 2.80 and a rated steam output of 0.75t / h is configured as the waste heat utilization equipment for the 80℃ low-temperature section of flue gas.

[0028] When the heat pump's heating ratio increases, the output range of the gas turbine 1's power generation becomes wider, its peak-shaving capability is enhanced, and thermoelectric decoupling is achieved. This is especially effective in scenarios with high heat demand and low electricity demand. This flexibility is of great significance for renewable energy grid connection on the power generation side, power peak shaving on the grid side, and peak shaving and valley filling on the user side.

[0029] like Figure 2As shown, in this embodiment, the heat exchange ends of the conventional high-temperature heat pump 33 and the cascade high-temperature heat pump 34 are both fixed inside the flue 31. Other structures, such as the evaporator, compressor, and condenser, are fixed outside the flue 31. The high-temperature flue gas discharged from the gas turbine 1 enters the waste heat boiler 32 through the flue 31 for primary waste heat recovery. The medium-temperature flue gas discharged from the waste heat boiler 32 after heat exchange re-enters the flue 31, first contacting the heat exchange end of the conventional high-temperature heat pump 33 for secondary waste heat recovery. After heat exchange, the low-temperature flue gas undergoes tertiary waste heat recovery through the cascade high-temperature heat pump 34 before being discharged as ultra-low-temperature flue gas. During this process, the steam generated by the waste heat boiler 32, the conventional high-temperature heat pump 33, and the cascade high-temperature heat pump 34 is supplied to the user terminal 2 through the steam pipe 4. This three-stage waste heat recovery path covers the entire temperature range of the flue gas, significantly improving overall thermal efficiency.

[0030] In this embodiment, the waste heat recovery principle of the conventional high-temperature heat pump 33 is as follows: the refrigerant in the evaporator absorbs heat and vaporizes in the waste heat environment; the compressor further compresses the refrigerant gas into a high-temperature and high-pressure gas, and the high-temperature refrigerant releases heat in the condenser (heating water to generate steam), and then the refrigerant condenses into a liquid; the refrigerant is depressurized and cooled by the throttling valve and re-enters the evaporator, and the cooled water is sent back to the condenser to complete the cycle.

[0031] The waste heat recovery principle of the cascade high-temperature heat pump 34 is as follows: it combines conventional compression heat pumps and conventional absorption heat pumps, such as compression-absorption composite high-temperature heat pump cycles, to construct large temperature rise cycle and high-temperature output cycle. After multiple heat exchange and temperature rise, the recovered low-temperature flue gas waste heat can be raised to a higher temperature and output to the outside, so as to realize the purpose of using waste heat to raise the feed water temperature and produce high-temperature steam. The remaining ultra-low temperature flue gas is discharged from the system.

[0032] The multi-energy complementary energy module includes a photovoltaic power generation unit 6, a power distribution unit 7, and an electrolysis hydrogen production unit 8. The electricity generated by the photovoltaic power generation unit 6 is transported to the power distribution unit 7 and the electrolysis hydrogen production unit 8 through the transmission line 5. The electrolysis hydrogen production unit 8 uses municipal water as raw material, and the produced hydrogen is connected to the fuel inlet of the gas turbine 1 (combustion chamber) through the hydrogen transmission pipeline 9 and the hydrogen storage buffer unit 10 (used to balance supply and demand fluctuations and ensure stable fuel supply). In this embodiment, in addition to hydrogen, natural gas is also provided to ensure stable combustion in the combustion chamber.

[0033] Multi-energy complementary energy modules utilize distributed energy technology, prioritizing solar energy and supplementing it with gas energy (natural gas, hydrogen) and energy storage to generate electricity, giving full play to the characteristics of various energy sources and achieving mutual promotion, mutual assistance between surplus and shortage, and balanced development of clean energy.

[0034] An energy storage unit 11 is connected to the transmission line 5 between the photovoltaic power generation unit 6 and the power distribution unit 7. This unit stores surplus photovoltaic power and serves multiple purposes, including peak shaving and valley filling, providing backup energy, and saving electricity costs, which helps optimize resource allocation.

[0035] The receiving end of the power distribution unit 7 is connected to the output end of the gas turbine 1 via the transmission line 5. In this embodiment, a municipal power supply is also provided to enhance the power dispatch capability. The sending end of the power distribution unit 7 is connected to the conventional high-temperature heat pump 33, the cascade high-temperature heat pump 34, and the user terminal 2 via the transmission line 5, respectively. That is, the power distribution unit 7 integrates the electrical energy of the gas turbine 1, the photovoltaic power generation unit 6, and the energy storage unit 11, converts the voltage, and distributes it to the conventional high-temperature heat pump 33, the cascade high-temperature heat pump 34, and the user terminal 2.

[0036] The overall operation mode is as follows:

[0037] ① Energy production and power generation: When there is sufficient sunlight, the photovoltaic power generation unit 6 generates electricity first. The electricity is divided into two paths: directly supplied to the power distribution unit 7 or sent to the electrolysis hydrogen production unit 8 to produce hydrogen. The surplus electricity is stored in the energy storage unit 11, and the surplus hydrogen is stored in the hydrogen storage buffer unit 10. The gas turbine 1 generates electricity by burning hydrogen or conventional fuel, and the electricity is sent to the power distribution unit 7 via the transmission line 5.

[0038] ② Waste heat recovery in stages: The exhaust gas from the gas turbine 1 is successively recovered through a waste heat boiler 32, a conventional high-temperature heat pump 33, and a cascade high-temperature heat pump 34. The steam generated by the three stages of equipment is delivered to the user terminal 2 for energy supply through steam pipeline 4.

[0039] ③ Multi-energy complementarity: The power distribution unit 7 integrates the electrical energy of the gas turbine 1, photovoltaic power generation unit 6, and energy storage unit 11, converts the voltage, and distributes it to the conventional / cascade high-temperature heat pump 34 (driving its operation) and supplies power to the user terminal 2.

[0040] ④ System optimization and peak shaving: Prioritize solar energy, supplemented by gas turbine 1 / hydrogen / energy storage, to achieve mutual support between surplus and shortage and pollution control.

[0041] Therefore, this utility model adopts a multi-stage gas turbine waste heat recovery system based on heat pump coupling, which deeply integrates three-stage waste heat recovery with multi-energy complementary power supply to construct a safe, stable, efficient, and low-pollution demonstration energy station. Among them, photovoltaic hydrogen production and energy storage units form a closed-loop buffer to avoid external power grid fluctuations; full-temperature range flue gas recovery effectively improves the overall thermal efficiency; combining solar-driven heat pumps, hydrogen power generation, and energy storage for peak shaving and valley filling achieves energy self-balancing; the cascade heat pump overcomes the low-temperature limitation, and the thermoelectric decoupling design broadens the unit's peak shaving range, completely solving the defects of insufficient waste heat recovery, unstable thermoelectric coupling, and heat pump dependence on the power grid in traditional systems.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solution of this utility model, and these modifications or equivalent substitutions cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of this utility model.

Claims

1. A multi-stage gas turbine waste heat recovery system based on heat pump coupling, characterized in that: The system includes a gas turbine and a user terminal. The exhaust end of the gas turbine is connected to a three-stage waste heat recovery assembly. The output end of the three-stage waste heat recovery assembly is connected to the user terminal via a steam pipe. The output end of the gas turbine is connected to a multi-energy complementary energy module. The multi-energy complementary energy module is connected to the three-stage waste heat recovery assembly and the user terminal via power transmission lines. The three-stage waste heat recovery assembly includes a flue connected to the exhaust end of the gas turbine and a waste heat boiler, a conventional high-temperature heat pump, and a cascade high-temperature heat pump arranged sequentially on the flue. The waste heat boiler, the conventional high-temperature heat pump, and the cascade high-temperature heat pump are all connected to the user terminal through the steam pipeline. The multi-energy complementary energy module includes a photovoltaic power generation unit, a power distribution unit, and an electrolysis hydrogen production unit. The output end of the photovoltaic power generation unit is connected to the power distribution unit and the electrolysis hydrogen production unit respectively through the power transmission line. The output end of the electrolysis hydrogen production unit is connected to the fuel inlet of the gas turbine through a hydrogen transmission pipeline and a hydrogen storage buffer unit.

2. The multi-stage gas turbine waste heat recovery system based on heat pump coupling according to claim 1, characterized in that: An energy storage unit is connected to the transmission line between the photovoltaic power generation unit and the power distribution unit.

3. The multi-stage gas turbine waste heat recovery system based on heat pump coupling according to claim 1, characterized in that: The power receiving end of the power distribution unit is connected to the output end of the gas turbine through the power transmission line, and the power sending end of the power distribution unit is connected to the conventional high-temperature heat pump, the cascade high-temperature heat pump, and the user terminal through the power transmission line respectively.

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