Compressed air energy storage and carbon capture coupling system

Abstract

The present invention relates to a compressed air energy storage and carbon capture coupling system, comprising a first heat exchanger, a first gas-liquid separator, an engine, a low-pressure compressor, a high-pressure compressor, a second heat exchanger, a third heat exchanger, a first absorption tower, a gas storage tank, a first turbine, a second gas-liquid separator, a first water pump, a second absorption tower, a second turbine, a third gas-liquid separator, a second water pump, a gas recovery compressor, a fourth heat exchanger, a throttle valve, a fifth heat exchanger, a high-pressure turbine, a sixth heat exchanger, a low-pressure turbine, a generator, a first cold storage device, a first oil pump, a first heat storage device, a second heat storage device, a second oil pump, a second heat storage device and a third oil pump. The present invention can reduce water resource consumption and is more environmentally friendly.

Description

Technical Field

[0001] The invention relates to a compressed air energy storage and carbon capture coupling system. Background Art

[0002] The amine-based solvent absorption method has a wide range of applications and good absorption capacity and reaction performance, but it has the disadvantages of equipment corrosion, high regeneration energy consumption, and the solvent being affected by SO 2 and O 2 The adsorption separation method has low regeneration energy consumption and is reversible, which is suitable for low concentration CO 2 Capture, but CO 2 The capture performance needs to be improved, and different adsorbent materials need to be considered in different scenarios. The membrane separation method is simple in technology, has low energy consumption and high separation purity, but there are problems such as the mutual restriction of polymer membrane permeability and selectivity, and the performance is affected by temperature and pressure conditions. Low-temperature separation can capture and recover liquid CO 2 , which is beneficial to CO 2 However, it has high energy consumption and is only suitable for CO under high concentration and high pressure conditions. 2 The traditional water-based capture method is simple and environmentally friendly, but it 2 When the concentration is low, it requires a lot of water, consumes a lot of energy, and is relatively less competitive.

[0003] In view of this, the inventor of this case conducted in-depth research on the above-mentioned issues, which led to the emergence of this case. Summary of the invention

[0004] The object of the present invention is to provide an environmentally friendly compressed air energy storage and carbon capture coupling system that can reduce water resource consumption.

[0005] In order to achieve the above object, the present invention adopts such technical solution:

[0006] A compressed air energy storage and carbon capture coupling system comprises a first heat exchanger, a first gas-liquid separator, an engine, a low-pressure compressor, a high-pressure compressor, a second heat exchanger, a third heat exchanger, a first absorption tower, a gas storage tank, a first turbine, a second gas-liquid separator, a first water pump, a second absorption tower, a second turbine, a third gas-liquid separator, a second water pump, a gas recovery compressor, a fourth heat exchanger, a throttle valve, a fifth heat exchanger, a high-pressure turbine, a sixth heat exchanger, a low-pressure turbine, a generator, a first cold storage device, a first oil pump, a first heat storage device, a second heat storage device, a second oil pump, a second heat storage device and a third oil pump, wherein an air inlet of the first heat exchanger is connected to a flue gas outlet of a power plant, and the first heat exchanger The air outlet of the first gas-liquid separator is connected to the air inlet of the first gas-liquid separator, the air outlet of the first gas-liquid separator is connected to the air inlet of the low-pressure compressor, the air outlet of the low-pressure compressor is connected to the air inlet of the second heat exchanger, the air outlet of the second heat exchanger is connected to the air inlet of the high-pressure compressor, the air outlet of the high-pressure compressor is connected to the air inlet of the third heat exchanger, the air outlet of the third heat exchanger is connected to the air inlet of the first absorption tower, the air outlet of the first absorption tower is connected to the gas storage tank, the liquid outlet of the first absorption tower is connected to the liquid inlet of the second gas-liquid separator through the first turbine, the air outlet of the second gas-liquid separator is connected to the air inlet of the second absorption tower, and the liquid outlet of the second gas-liquid separator is connected to the liquid inlet of the first absorption tower through the first water pump. The gas outlet of the second absorption tower is connected to the gas inlet of the gas recovery compressor, the liquid outlet of the second absorption tower is connected to the liquid inlet of the third gas-liquid separator through the second turbine, the liquid outlet of the third gas-liquid separator is connected to the liquid inlet of the second absorption tower through the second water pump, the gas outlet of the gas recovery compressor is connected to the gas inlet of the fourth heat exchanger, the gas outlet of the fourth heat exchanger is connected to the gas storage tank, the liquid inlet of the fourth heat exchanger is connected to the liquid outlet of the second cold storage device, the liquid outlet of the fourth heat exchanger is connected to the liquid inlet of the second heat storage device, the gas storage tank is connected to the gas inlet of the fifth heat exchanger through the throttle valve, the gas outlet of the fifth heat exchanger is connected to the gas inlet of the high-pressure turbine, the gas outlet of the high-pressure turbine is connected to the gas storage tank, the liquid inlet of the fourth heat exchanger is connected to the liquid outlet of the second cold storage device, the liquid outlet of the fourth heat exchanger is connected to the liquid inlet of the second heat storage device, the gas storage tank is connected to the gas inlet of the fifth heat exchanger through the throttle valve, the gas outlet of the fifth heat exchanger is connected to the gas inlet of the high-pressure turbine, and the gas outlet of the high-pressure turbine is connected to the gas storage tank. The air inlets of the six heat exchangers are connected, the air outlet of the sixth heat exchanger is connected to the air inlet of the low-pressure turbine, the generator, the low-pressure turbine and the high-pressure turbine are transmission-connected, the engine, the low-pressure compressor and the high-pressure compressor are transmission-connected, the generator, the low-pressure turbine and the high-pressure turbine are transmission-connected, the liquid inlet of the second heat exchanger and the liquid inlet of the third heat exchanger are both connected to the liquid outlet of the first cold storage device, the liquid outlet of the second heat exchanger and the liquid outlet of the third heat exchanger are both connected to the liquid inlet of the first heat storage device, the liquid inlet of the fifth heat exchanger and the liquid inlet of the sixth heat exchanger are both connected to the liquid outlet of the first heat storage device, and the liquid outlet of the fifth heat exchanger and the liquid outlet of the sixth heat exchanger are both connected to the liquid inlet of the first cold storage device.

[0007] As a preferred embodiment of the present invention, the first cold storage device is connected to both the liquid inlet of the second heat exchanger and the liquid inlet of the third heat exchanger through a first oil pump.

[0008] As a preferred embodiment of the present invention, the liquid outlet of the first heat storage device is connected to the liquid inlet of the fifth heat exchanger and the liquid inlet of the sixth heat exchanger through a third oil pump.

[0009] As a preferred embodiment of the present invention, the liquid inlet of the fourth heat exchanger is connected to the liquid inlet of the second cold storage device through a second oil pump.

[0010] The technical solution of the present invention has the following beneficial effects:

[0011] 1. The amine-based solvent carbon capture method commonly used in industry has high energy consumption and can cause problems such as equipment corrosion and solvent degradation. This patent uses a water-based carbon capture method, which is simple in technology and environmentally friendly.

[0012] 2. Traditional water-based carbon capture method directly captures CO at normal pressure. 2 , which places great demands on water resources. This patent uses pressurized circulating water to absorb CO 2 , and then reduce the pressure to CO 2 It evaporates and is recycled through water pumps and turbines, greatly reducing the consumption of water resources.

[0013] 3. The compression heat in the traditional compressed air energy storage charging process is absorbed by the heat transfer oil and used to preheat the gas during the discharge process to improve the cycle efficiency. 2 When the volume of the gas storage tank is constant, more compression heat will be absorbed by the heat transfer oil during the charging process. In addition to being supplied to the discharge process to preheat the gas, the heat of the heat storage device can also be used to heat the domestic water for residents, achieving cogeneration of heat and power and multiple benefits.

[0014] 4. Traditional compressed air energy storage can only achieve the purpose of energy storage and has only a single benefit. This patent couples compressed air energy storage with carbon capture, and can not only store energy for peak load regulation of the power plant's surplus power, but also capture the CO2 emitted by the power plant. 2 , reduce environmental impact and make the system more valuable. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a system flow chart of the present invention.

[0016] In the figure:

[0017] 1-first heat exchanger; 2-first gas-liquid separator; 3-engine; 4-low-pressure compressor; 5-second heat exchanger; 6-high-pressure compressor; 7-third heat exchanger; 8-first absorption tower; 9-gas storage tank; 10-first turbine; 11-second gas-liquid separator; 12-first water pump; 13-second absorption tower; 14-second turbine; 15-third gas-liquid separator; 16-second water pump; 17-gas recovery compressor; 18-fourth heat exchanger; 19-throttle valve; 20-fifth heat exchanger; 21-high-pressure turbine; 22-sixth heat exchanger; 23-low-pressure turbine; 24-generator; 25-first cold storage device; 26-first oil pump; 27-first heat storage device, 28-second cold storage device, 29-second oil pump; 30-second heat storage device; 31-third oil pump DETAILED DESCRIPTION

[0018] In order to further explain the technical solution of the present invention, it is described in detail below in conjunction with embodiments.

[0019] Reference Figure 1 , compressed air energy storage and carbon capture coupling system, through the compressor unit to assist the pressurization of flue gas emitted by the power plant, improve the CO 2 The solubility in water can effectively reduce the energy consumption of water-based carbon capture and improve economic benefits. The system uses the surplus electricity of the power plant to drive the compressor, and can also store electricity while capturing carbon, improving the power generation flexibility of the power plant.

[0020] The flue gas discharged from the power plant is mainly composed of H 2 O、CO 2 、N 2 , O 2 When high-temperature and high-humidity flue gas is directly introduced into the compressor unit, it will cause greater energy consumption. Therefore, it is necessary to pre-treat the flue gas before it enters the compressor unit. The power plant flue gas (322.15K, 100kPa) is first cooled to a temperature close to the ambient temperature in the first heat exchanger 1. Then, the saturated water in the flue gas is converted into a liquid phase and discharged from the first separator 2, leaving a CO-rich 2 The air is sent to the compressor unit for compression.

[0021] During the flue gas compression process (charging process), the surplus electricity generated by the power plant is used to power the engine 3 to drive the 2-stage compressor unit (low-pressure compressor 4 and high-pressure compressor 6). After each compression, thermal oil is used to absorb the compressed CO2-rich gas from the second heat exchanger 5 and the third heat exchanger 7. 2 The heat transfer oil is sent from the first cold storage device 25 to each heat exchanger by the first oil pump 26, and is stored in the first heat storage device 27 after heat exchange. 2The air is cooled to near ambient temperature in the third heat exchanger 7 and then enters the first absorption tower 8 for CO 2 Absorption capture process.

[0022] CO 2 The absorption process is divided into two stages. In the first stage, the CO2-rich 2 The high-pressure air is fully in contact with the circulating water in the first absorption tower 8. 2 Most of the CO in the air 2 and a small amount of N 2 , O 2 Dissolved in the circulating water, so CO 2 The mass fraction of dissolved N is higher than that of other gases. The undissolved high-pressure gas is sent to the gas storage tank 9 for storage, and is released at the appropriate time to expand in the turbine to generate electricity. 2 , O 2 , CO 2 The circulating water mixed with the gas flows into the first turbine 10 to expand and reduce the pressure and generate electricity to recover part of the electricity. The pressure drop causes the solubility of the gas to decrease, which will cause part of the gas to be released from the circulating water. Volatile gas (N 2 , O 2 , CO 2 ) and circulating water are separated in the second gas-liquid separator 11, and then the circulating water is pressurized by the first water pump 12 and flows into the first absorption tower 8 to repeat the absorption process. 2 The mass fraction is higher than that of the CO-rich 2 In order to further enrich the CO 2 , the same operation is adopted to introduce the second stage. In this stage, the undissolved gas in the second absorption tower 13 is compressed by the gas recovery compressor 17 and cooled by the fourth heat exchanger 18 and then sent to the gas storage tank 9 for storage, and the heat is stored in the second heat storage device 30. High-purity CO 2 It is discharged from the third gas-liquid separator 15 and stored through existing mineral carbonization or other carbon storage technologies.

[0023] The high-pressure gas stored in the gas storage tank 9 is released during the peak period of electricity demand (discharge process), converting pressure energy into electrical energy to assist the power plant in power supply and balance the load of the power grid. The pressure in the gas storage tank 9 will decrease as the gas is discharged, so a throttle valve 19 is required to keep the pressure of the gas entering the turbine constant. The throttled gas will pass through the fifth heat exchanger 20 and the sixth heat exchanger 22 for heat exchange before entering the high-pressure turbine 21 and the low-pressure turbine 23 for expansion, absorbing the heat from the heat transfer oil in the first heat storage device 27, increasing the turbine inlet gas temperature, and increasing the turbine output power. The heat transfer oil after heat exchange flows into the first cold storage device 25 for storage and recycling. The two-stage turbine unit drives the generator 24 to generate electricity and output electricity to the power grid.

[0024] In order to solve the existing industrial CO 2 In order to solve the problem of high energy consumption in the capture process of capture and storage technology, we propose a method of combining water-based capture and compressed air energy storage to reduce the CO in the flue gas emitted by coal-fired power plants. 2 Capture and storage. The energy consumption of water-based capture depends on CO 2 By introducing compressed air energy storage technology, the surplus electricity of the power plant is used to drive the compressor unit to raise the flue gas to a high pressure of 7.5MPa. 2 The partial pressure of CO also increases accordingly. Under the restriction of flue gas concentration in power plants, 2 The increase in partial pressure will also increase its solubility in water, reducing the capture of CO 2 The unabsorbed gas is stored in the gas storage tank 9 and released during the peak period of power grid consumption to drive the turbine unit to generate electricity to balance the grid load. In addition, the traditional water-based capture method requires a lot of water. This patent captures CO based on the solubility difference formed by the gas pressure difference. 2 , dissolving CO under high pressure 2 , and then reduce the pressure to CO 2 The water pumps and turbines are used to increase and reduce the pressure of the circulating water, which greatly reduces the demand for water resources and improves the economic benefits of the system.

[0025] The product form of the present invention is not limited to the embodiments of this case. Any appropriate changes or modifications made by anyone with similar ideas should be deemed to be within the patent scope of the present invention.

Claims

1. Compressed air energy storage and carbon capture coupling system, characterized by: The invention comprises a first heat exchanger, a first gas-liquid separator, an engine, a low-pressure compressor, a high-pressure compressor, a second heat exchanger, a third heat exchanger, a first absorption tower, a gas storage tank, a first turbine, a second gas-liquid separator, a first water pump, a second absorption tower, a second turbine, a third gas-liquid separator, a second water pump, a gas recovery compressor, a fourth heat exchanger, a throttle valve, a fifth heat exchanger, a high-pressure turbine, a sixth heat exchanger, a low-pressure turbine, a generator, a first cold storage device, a first oil pump, a first heat storage device, a second heat storage device, a second oil pump, a second heat storage device and a third oil pump, wherein the air inlet of the first heat exchanger is connected to the flue gas exhaust port of the power plant, and the air outlet of the first heat exchanger is connected to the flue gas exhaust port of the power plant. to the air inlet of the first gas-liquid separator, the air outlet of the first gas-liquid separator is connected to the air inlet of the low-pressure compressor, the air outlet of the low-pressure compressor is connected to the air inlet of the second heat exchanger, the air outlet of the second heat exchanger is connected to the air inlet of the high-pressure compressor, the air outlet of the high-pressure compressor is connected to the air inlet of the third heat exchanger, the air outlet of the third heat exchanger is connected to the air inlet of the first absorption tower, the air outlet of the first absorption tower is connected to the gas storage tank, the liquid outlet of the first absorption tower is connected to the liquid inlet of the second gas-liquid separator through the first turbine, the air outlet of the second gas-liquid separator is connected to the air inlet of the second absorption tower, and the liquid outlet of the second gas-liquid separator is connected to the first absorption tower through the first water pump The gas outlet of the second absorption tower is connected to the gas inlet of the gas recovery compressor, the liquid outlet of the second absorption tower is connected to the liquid inlet of the third gas-liquid separator through the second turbine, the liquid outlet of the third gas-liquid separator is connected to the liquid inlet of the second absorption tower through the second water pump, the gas outlet of the gas recovery compressor is connected to the gas inlet of the fourth heat exchanger, the gas outlet of the fourth heat exchanger is connected to the gas storage tank, the liquid inlet of the fourth heat exchanger is connected to the liquid outlet of the second cold storage device, the liquid outlet of the fourth heat exchanger is connected to the liquid inlet of the second heat storage device, the gas storage tank is connected to the gas inlet of the fifth heat exchanger through the throttle valve, and the gas outlet of the fifth heat exchanger is connected to the gas inlet of the high-pressure turbine , the air outlet of the high-pressure turbine is connected to the air inlet of the sixth heat exchanger, the air outlet of the sixth heat exchanger is connected to the air inlet of the low-pressure turbine, the generator, the low-pressure turbine and the high-pressure turbine are transmission-connected, the engine, the low-pressure compressor and the high-pressure compressor are transmission-connected, the liquid inlet of the second heat exchanger and the liquid inlet of the third heat exchanger are both connected to the liquid outlet of the first cold storage device, the liquid outlet of the second heat exchanger and the liquid outlet of the third heat exchanger are both connected to the liquid inlet of the first heat storage device, the liquid inlet of the fifth heat exchanger and the liquid inlet of the sixth heat exchanger are both connected to the liquid outlet of the first heat storage device, and the liquid outlet of the fifth heat exchanger and the liquid outlet of the sixth heat exchanger are both connected to the liquid inlet of the first cold storage device.

2. The compressed air energy storage and carbon capture coupling system according to claim 1, characterized in that: The first cold storage device is connected to both the liquid inlet of the second heat exchanger and the liquid inlet of the third heat exchanger through a first oil pump.

3. The compressed air energy storage and carbon capture coupling system according to claim 2, characterized in that: The liquid outlet of the first heat storage device is connected to the liquid inlet of the fifth heat exchanger and the liquid inlet of the sixth heat exchanger through a third oil pump.

4. The compressed air energy storage and carbon capture coupling system according to claim 3, characterized in that: The liquid inlet of the fourth heat exchanger is connected to the liquid inlet of the second cold storage device through a second oil pump.

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