Integrated energy storage large scale carbon capture coal-fired power plant and method of operation thereof

Abstract

The present disclosure provides a large-scale carbon capture coal-fired power plant integrated with energy storage and a method for operating the same, wherein the carbon capture coal-fired power plant comprises a coal-fired power generation system, a carbon capture system and an energy storage system; a molten salt passage between a low-temperature tank and a first medium-temperature molten salt tank is used to absorb heat from a lean liquid circulation passage of the carbon capture system; a molten salt passage between the first medium-temperature molten salt tank and a high-temperature molten salt tank is used to absorb heat from a reheated steam passage of the coal-fired power generation system; a molten salt passage between the high-temperature molten salt tank and a second medium-temperature molten salt tank is used to release heat to a steam heating passage of the carbon capture system, and then absorb heat from a low-pressure cylinder steam input passage of the coal-fired power generation system; and a molten salt passage between the second medium-temperature molten salt tank and the low-temperature tank is used to release heat to a rich liquid circulation passage of the carbon capture system. In the large-scale carbon capture coal-fired power plant integrated with energy storage and the method for operating the same, the safe and flexible operation of the carbon capture coal-fired power plant is facilitated.

Description

Technical Field

[0001] This disclosure relates to the field of coal-fired power plant technology, and in particular to a large-scale carbon capture coal-fired power plant with integrated energy storage and its operation method. Background Technology

[0002] Energy systems are gradually moving towards higher renewable energy rates, higher energy efficiency, lower emissions, and lower pollution. Therefore, for the power industry, which relies heavily on coal, developing carbon capture technology can help address the current problem of excessive carbon emissions caused by over-reliance on coal.

[0003] With the energy transition to clean energy and the large-scale grid connection of new energy sources, it is urgent to improve the peak-shaving and valley-filling capabilities of existing coal-fired power plants in order to make full use of renewable energy. Meanwhile, coal-fired power plants equipped with carbon capture systems are also researching methods to improve their peak-shaving and frequency regulation capabilities in order to adapt to the existing energy structure.

[0004] Compared to conventional coal-fired power plants, peak shaving and frequency regulation are more difficult and challenging for carbon capture coal-fired power plants. There is a strong interaction between the carbon capture system and the coal-fired power generation system in carbon capture coal-fired power plants. Combined with the influence of various factors, carbon capture coal-fired power plants find it difficult to quickly adapt to load changes and ensure the safe and stable operation of the units. Summary of the Invention

[0005] This disclosure aims to at least partially address one of the technical problems in the related art.

[0006] Therefore, the purpose of this disclosure is to provide a large-scale carbon capture coal-fired power plant with integrated energy storage and its operation method.

[0007] To achieve the above objectives, the first aspect of this disclosure provides a large-scale carbon capture coal-fired power plant with integrated energy storage, comprising: a coal-fired power generation system, a carbon capture system, and an energy storage system; the energy storage system includes: a cryogenic tank, a first intermediate-temperature molten salt tank, a high-temperature molten salt tank, and a second intermediate-temperature molten salt tank; wherein the molten salt output end of the cryogenic tank is connected to the molten salt input end of the first intermediate-temperature molten salt tank, and the molten salt passage between the cryogenic tank and the first intermediate-temperature molten salt tank is used to absorb heat from the lean liquid circulation passage of the carbon capture system; the molten salt output end of the first intermediate-temperature molten salt tank is connected to the molten salt input end of the high-temperature molten salt tank, and the first intermediate-temperature molten salt tank and the high-temperature molten salt tank are connected to the first intermediate-temperature molten salt tank. The molten salt passage between the high-temperature molten salt tanks is used to absorb heat from the reheat steam passage of the coal-fired power generation system; the molten salt output end of the high-temperature molten salt tank is connected to the molten salt input end of the second medium-temperature molten salt tank, and the molten salt passage between the high-temperature molten salt tank and the second medium-temperature molten salt tank is used to release heat to the steam heating passage of the carbon capture system, and then absorb heat from the low-pressure cylinder steam input passage of the coal-fired power generation system; the molten salt output end of the second medium-temperature molten salt tank is connected to the molten salt input end of the low-temperature tank, and the molten salt passage between the second medium-temperature molten salt tank and the low-temperature tank is used to release heat to the rich liquid circulation passage of the carbon capture system.

[0008] Optionally, the energy storage system further includes: a first heat exchanger; wherein, a first channel of the first heat exchanger is disposed between the molten salt output end of the low-temperature tank and the molten salt input end of the first medium-temperature molten salt tank, and the molten salt input end of the first channel of the first heat exchanger is connected to the molten salt output end of the low-temperature tank, and the molten salt output end of the first channel of the first heat exchanger is connected to the molten salt input end of the first medium-temperature molten salt tank; a second channel of the first heat exchanger is connected to the lean liquid output end of the desorption tower in the carbon capture system, and the lean liquid output end of the second channel of the first heat exchanger is connected to the lean liquid input end of the absorption tower in the carbon capture system; the first channel and the second channel of the first heat exchanger exchange heat, so that the molten salt between the low-temperature tank and the first medium-temperature molten salt tank absorbs heat from the lean liquid of the carbon capture system.

[0009] Optionally, the energy storage system further includes: a second heat exchanger; wherein, a first channel of the second heat exchanger is disposed between the molten salt output end of the first medium-temperature molten salt tank and the molten salt input end of the first high-temperature molten salt tank, and the molten salt input end of the first channel of the second heat exchanger is connected to the molten salt output end of the first medium-temperature molten salt tank, and the molten salt output end of the first channel of the second heat exchanger is connected to the molten salt input end of the high-temperature molten salt tank; a second channel steam input end of the second heat exchanger is connected to the reheat steam output end of the boiler in the coal-fired power generation system, and the second channel steam output end of the second heat exchanger is connected to the steam input end of the low-pressure cylinder in the coal-fired power generation system; the first channel and the second channel of the second heat exchanger exchange heat, so that the molten salt between the first medium-temperature molten salt tank and the high-temperature molten salt tank absorbs heat from the reheat steam of the coal-fired power generation system.

[0010] Optionally, the energy storage system further includes: a first regulating valve, which is disposed at the second channel steam input end of the second heat exchanger, and the first regulating valve is used to regulate the heat absorbed by the molten salt between the first medium-temperature molten salt tank and the high-temperature molten salt tank from the reheat steam of the coal-fired power generation system.

[0011] Optionally, the energy storage system further includes: a third heat exchanger; wherein, the first channel of the third heat exchanger is disposed between the molten salt output end of the high-temperature molten salt tank and the molten salt input end of the second medium-temperature molten salt tank, and the molten salt input end of the first channel of the third heat exchanger is connected to the molten salt output end of the high-temperature molten salt tank, and the molten salt output end of the first channel of the third heat exchanger is connected to the molten salt input end of the second medium-temperature molten salt tank; the condensate input end of the second channel of the third heat exchanger is connected to the condensate output end of the desorption tower in the carbon capture system, and the steam output end of the second channel of the third heat exchanger is connected to the steam input end of the desorption tower in the carbon capture system; the first channel and the second channel of the third heat exchanger exchange heat to release heat from the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank to the condensate of the carbon capture system before the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank absorbs heat from the low-pressure cylinder inlet steam of the coal-fired power generation system.

[0012] Optionally, the energy storage system further includes: a fourth heat exchanger; wherein, the first channel of the fourth heat exchanger is disposed between the molten salt output end of the high-temperature molten salt tank and the molten salt input end of the second medium-temperature molten salt tank, and the molten salt input end of the first channel of the fourth heat exchanger is connected to the molten salt output end of the high-temperature molten salt tank, and the molten salt output end of the first channel of the fourth heat exchanger is connected to the molten salt input end of the second medium-temperature molten salt tank; the steam input end of the second channel of the fourth heat exchanger is connected to the steam input end of the low-pressure cylinder of the coal-fired power generation system, and the condensate output end of the second channel of the fourth heat exchanger is connected to the condensate input end of the deaerator in the coal-fired power generation system; the first channel and the second channel of the fourth heat exchanger exchange heat so that after the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank releases heat to the condensate of the carbon capture system, the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank absorbs heat from the inlet steam of the low-pressure cylinder of the coal-fired power generation system.

[0013] Optionally, the energy storage system further includes a second regulating valve, which is disposed at the steam input end of the second channel of the fourth heat exchanger, and is used to regulate the heat absorbed by the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank from the low-pressure cylinder inlet steam of the coal-fired power generation system.

[0014] Optionally, the energy storage system further includes: a fifth heat exchanger; wherein, the first channel of the fifth heat exchanger is disposed between the molten salt output end of the second medium-temperature molten salt tank and the molten salt input end of the low-temperature tank, and the molten salt input end of the first channel of the fifth heat exchanger is connected to the molten salt output end of the second medium-temperature molten salt tank, and the molten salt output end of the first channel of the fifth heat exchanger is connected to the molten salt input end of the low-temperature tank; the rich liquid input end of the second channel of the fifth heat exchanger is connected to the rich liquid output end of the absorption tower in the carbon capture system, and the rich liquid output end of the second channel of the fifth heat exchanger is connected to the rich liquid input end of the desorption tower in the carbon capture system; the first channel and the second channel of the fifth heat exchanger exchange heat to release heat from the molten salt between the second medium-temperature molten salt tank and the low-temperature tank to the rich liquid of the carbon capture system.

[0015] Optionally, the molten salt output terminal of the first medium-temperature molten salt tank is connected to the molten salt input terminal of the second medium-temperature molten salt tank, and the molten salt input terminal of the first medium-temperature molten salt tank is connected to the molten salt output terminal of the second medium-temperature molten salt tank.

[0016] A second aspect of this disclosure provides an operation method for a large-scale carbon capture coal-fired power plant with integrated energy storage as provided in the first aspect of this disclosure, comprising: obtaining the rated load and actual load of the coal-fired power generation system in the power plant; when the actual load of the coal-fired power generation system is greater than a first proportion of the rated load, increasing the heat absorbed by the molten salt passage between the high-temperature molten salt tank and the second medium-temperature molten salt tank in the power plant from the low-pressure cylinder steam input passage of the coal-fired power generation system, and decreasing the heat absorbed by the molten salt passage between the first medium-temperature molten salt tank and the high-temperature molten salt tank in the power plant from the reheat steam passage of the coal-fired power generation system; when the actual load of the coal-fired power generation system is less than a second proportion of the rated load, decreasing the heat absorbed by the molten salt passage between the high-temperature molten salt tank and the second medium-temperature molten salt tank in the power plant from the low-pressure cylinder steam input passage of the coal-fired power generation system, and increasing the heat absorbed by the molten salt passage between the first medium-temperature molten salt tank and the high-temperature molten salt tank in the power plant from the reheat steam passage of the coal-fired power generation system; wherein the second proportion is less than the first proportion.

[0017] The technical solution provided in this disclosure may include the following beneficial effects:

[0018] Based on the molten salt circulation in the low-temperature tank, the first medium-temperature molten salt tank, the high-temperature molten salt tank, and the second medium-temperature molten salt tank in the energy storage system, as well as the heat exchange between the molten salt and the reheat steam and low-pressure cylinder inlet steam in the coal-fired power generation system, and the heat exchange between the molten salt and the lean liquid, rich liquid, and condensate in the carbon capture system, an effective buffer can be formed between the coal-fired power generation system and the carbon capture system when the load changes, thereby facilitating the safe and flexible operation of the capture coal-fired power plant.

[0019] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0020] The above and / or additional aspects and advantages of this disclosure will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram of the structure of a large-scale carbon capture coal-fired power plant with integrated energy storage proposed in one embodiment of this disclosure; As shown in the figure: 1. Low temperature tank, 2. First medium temperature molten salt tank, 3. Second medium temperature molten salt tank, 4. High temperature molten salt tank, 5. First heat exchanger, 6. Second heat exchanger, 7. Third heat exchanger, 8. Fourth heat exchanger, 9. Fifth heat exchanger, 10. First regulating valve, 11. Second regulating valve. 100. Absorption tower; 200. Desorption tower; 300. Rich liquid pump. Detailed Implementation

[0021] Embodiments of this disclosure are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are used only to explain this disclosure, and should not be construed as limiting this disclosure. Rather, embodiments of this disclosure include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0022] like Figure 1 As shown in the present disclosure, an embodiment of a large-scale carbon capture coal-fired power plant with integrated energy storage is proposed, including: a coal-fired power generation system, a carbon capture system and an energy storage system. The energy storage system includes: a cryogenic tank 1, a first medium-temperature molten salt tank 2, a high-temperature molten salt tank 4 and a second medium-temperature molten salt tank 3. The molten salt output end of the cryogenic tank 1 is connected to the molten salt input end of the first intermediate-temperature molten salt tank 2, and the molten salt passage between the cryogenic tank 1 and the first intermediate-temperature molten salt tank 2 is used to absorb heat from the lean liquid circulation passage of the carbon capture system; the molten salt output end of the first intermediate-temperature molten salt tank 2 is connected to the molten salt input end of the high-temperature molten salt tank 4, and the molten salt passage between the first intermediate-temperature molten salt tank 2 and the high-temperature molten salt tank 4 is used to absorb heat from the reheat steam passage of the coal-fired power generation system; the molten salt output end of the high-temperature molten salt tank 4 is connected to the molten salt input end of the second intermediate-temperature molten salt tank 3, and the molten salt passage between the high-temperature molten salt tank 4 and the second intermediate-temperature molten salt tank 3 is used to release heat to the steam heating passage of the carbon capture system, and then absorb heat from the low-pressure cylinder steam input passage of the coal-fired power generation system; the molten salt output end of the second intermediate-temperature molten salt tank 3 is connected to the molten salt input end of the cryogenic tank 1, and the molten salt passage between the second intermediate-temperature molten salt tank 3 and the cryogenic tank 1 is used to release heat to the rich liquid circulation passage of the carbon capture system.

[0023] It is understandable that, since the molten salt output end of the low-temperature tank 1 is connected to the molten salt input end of the first medium-temperature molten salt tank 2, and the molten salt passage between the low-temperature tank 1 and the first medium-temperature molten salt tank 2 absorbs heat from the lean liquid circulation passage of the carbon capture system, the low-temperature molten salt in the low-temperature tank 1 can be heated by the lean liquid of the carbon capture system into medium-temperature molten salt and stored in the first medium-temperature molten salt tank 2.

[0024] Since the molten salt output end of the first medium-temperature molten salt tank 2 is connected to the molten salt input end of the high-temperature molten salt tank 4, and the molten salt passage between the first medium-temperature molten salt tank 2 and the high-temperature molten salt tank 4 absorbs heat from the reheat steam passage of the coal-fired power generation system, the medium-temperature molten salt in the first medium-temperature molten salt tank 2 can be heated into high-temperature molten salt by the reheat steam of the coal-fired power generation system and stored in the high-temperature molten salt tank 4.

[0025] Since the molten salt output end of the high-temperature molten salt tank 4 is connected to the molten salt input end of the second medium-temperature molten salt tank 3, and the molten salt passage between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 releases heat to the steam heating passage of the carbon capture system and absorbs heat from the steam input passage of the low-pressure cylinder of the coal-fired power generation system, the condensate of the carbon capture system can be heated into high-temperature steam by the high-temperature molten salt in the high-temperature molten salt tank 4, thereby ensuring efficient heating and desorption of the rich liquid. In addition, the high-temperature molten salt after heat release can be heated into medium-temperature molten salt by the steam at the inlet of the low-pressure cylinder of the coal-fired power generation system and stored in the second medium-temperature molten salt tank 3.

[0026] Since the molten salt output end of the second intermediate-temperature molten salt tank 3 is connected to the molten salt input end of the low-temperature tank 1, and the molten salt passage between the second intermediate-temperature molten salt tank 3 and the low-temperature tank 1 releases heat to the rich liquid circulation passage of the carbon capture system, the rich liquid of the carbon capture system can be heated by the intermediate-temperature molten salt in the second intermediate-temperature molten salt tank 3, thereby ensuring efficient heating and desorption of the rich liquid.

[0027] Based on the molten salt circulation in the energy storage system, including the low-temperature tank 1, the first medium-temperature molten salt tank 2, the high-temperature molten salt tank 4, and the second medium-temperature molten salt tank 3, and the heat exchange between the molten salt and the reheat steam and low-pressure cylinder inlet steam in the coal-fired power generation system, as well as the heat exchange between the molten salt and the lean liquid, rich liquid, and condensate in the carbon capture system, an effective buffer can be formed between the coal-fired power generation system and the carbon capture system when the load changes, thereby facilitating the safe and flexible operation of the capture coal-fired power plant.

[0028] It should be noted that the carbon capture coal-fired power plant in this embodiment establishes an energy storage system between the coal-fired power generation system and the carbon capture system, forming a buffer zone during load changes, which facilitates the commercial application of the carbon capture coal-fired power plant. Furthermore, molten salt thermal energy storage technology reduces the requirements on the boiler side, achieving decoupling of the boiler and turbine, and significantly improving the safety and flexibility of the carbon capture coal-fired power plant.

[0029] In summary, the carbon capture coal-fired power plant of this embodiment can quickly adapt to load changes while ensuring the safe and stable operation of the unit.

[0030] The coal-fired power generation system includes: a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a generator, a condenser, a deaerator, etc. Specifically, the boiler provides main steam to the high-pressure cylinder and reheat steam to the intermediate-pressure cylinder through coal combustion. The steam performs work in the high-pressure cylinder, intermediate-pressure cylinder and low-pressure cylinder in sequence, and then drives the generator to generate electricity. At the same time, the steam after performing work is condensed in the condenser and deaerated in the deaerator before returning to the boiler to be recirculated and reheated into steam.

[0031] In addition, such as Figure 1As shown, the carbon capture system includes an absorption tower 100, a desorption tower 200, a rich liquor pump 300, etc. Specifically, the absorption tower 100 uses lean liquor to absorb carbon dioxide in the boiler flue gas and discharges purified flue gas. The lean liquor after absorbing carbon dioxide is converted into rich liquor and transported to the desorption tower 200 through the rich liquor pump 300. The desorption tower 200 uses high-temperature steam to heat the rich liquor and convert it into lean liquor and carbon dioxide. The lean liquor is returned to the absorption tower 100 for the circulation and purification of flue gas.

[0032] The carbon dioxide absorption tower 100 is an important industrial piece of equipment widely used in gas purification and waste gas treatment, especially in applications requiring the removal of carbon dioxide from gases. The following is a detailed introduction to the carbon dioxide absorption tower 100: The working principle of the carbon dioxide absorption tower 100 is primarily to effectively remove carbon dioxide from gases through physical and chemical methods. When gas enters the absorption tower 100, it passes through the packing layer inside the tower and interacts with the absorbent coated on the surface of the packing. This absorbent is generally a mixture of water and some specific chemical agents, possessing excellent absorption performance. As the gas rises within the tower, carbon dioxide molecules are gradually adsorbed by the absorbent, thereby reducing the concentration of carbon dioxide in the gas. To improve absorption efficiency, the packing inside the tower is usually designed with a specific shape to increase the contact area between the gas and the absorbent, promoting the reaction.

[0033] Cryogenic tank 1 is used to store cryogenic molten salt, first intermediate-temperature molten salt tank 2 and second intermediate-temperature molten salt tank 3 are used to store intermediate-temperature molten salt, and high-temperature molten salt tank 4 is used to store high-temperature molten salt. The specific types of cryogenic tank 1, first intermediate-temperature molten salt tank 2, second intermediate-temperature molten salt tank 3, and high-temperature molten salt tank 4 can be set according to actual needs and are not limited thereto. Molten salt transfer pumps can be installed on the passages between the tanks to achieve stable molten salt circulation.

[0034] like Figure 1 As shown, in some embodiments, the energy storage system further includes a first heat exchanger 5. The first channel of the first heat exchanger 5 is disposed between the molten salt output end of the cryogenic tank 1 and the molten salt input end of the first intermediate-temperature molten salt tank 2, and the molten salt input end of the first channel of the first heat exchanger 5 is connected to the molten salt output end of the cryogenic tank 1, and the molten salt output end of the first channel of the first heat exchanger 5 is connected to the molten salt input end of the first intermediate-temperature molten salt tank 2; the lean liquid input end of the second channel of the first heat exchanger 5 is connected to the lean liquid output end of the desorption tower 200 in the carbon capture system, and the lean liquid output end of the second channel of the first heat exchanger 5 is connected to the lean liquid input end of the absorption tower 100 in the carbon capture system; the first channel and the second channel of the first heat exchanger 5 exchange heat, so that the molten salt between the cryogenic tank 1 and the first intermediate-temperature molten salt tank 2 absorbs heat from the lean liquid of the carbon capture system.

[0035] Understandably, since the first channel molten salt inlet of the first heat exchanger 5 is connected to the molten salt outlet of the low-temperature tank 1, and the first channel molten salt outlet of the first heat exchanger 5 is connected to the molten salt inlet of the first medium-temperature molten salt tank 2, the low-temperature molten salt in the low-temperature tank 1 can enter the first medium-temperature molten salt tank 2 through the first channel of the first heat exchanger 5. Furthermore, since the second channel lean liquid inlet of the first heat exchanger 5 is connected to the lean liquid outlet of the desorption tower 200 in the carbon capture system, and the second channel lean liquid outlet of the first heat exchanger 5 is connected to the lean liquid inlet of the absorption tower 100 in the carbon capture system, the lean liquid of the desorption tower 200 can enter the absorption tower 100 through the second channel of the first heat exchanger 5.

[0036] Therefore, by utilizing the heat exchange between the first and second channels in the first heat exchanger 5, the molten salt between the low-temperature tank 1 and the first medium-temperature molten salt tank 2 can absorb heat from the lean liquid of the carbon capture system, thereby realizing the storage and utilization of the waste heat of the lean liquid, thereby improving the efficiency of the carbon capture coal-fired power plant and reducing the cost of the carbon capture coal-fired power plant.

[0037] The first heat exchanger 5 has a first channel and a second channel for direct or indirect heat exchange. The specific type of the first heat exchanger 5 can be set according to actual needs and is not restricted.

[0038] like Figure 1 As shown, in some embodiments, the energy storage system further includes a second heat exchanger 6. The first channel of the second heat exchanger 6 is disposed between the molten salt output end of the first intermediate-temperature molten salt tank 2 and the molten salt input end of the high-temperature molten salt tank 4, and the molten salt input end of the first channel of the second heat exchanger 6 is connected to the molten salt output end of the first intermediate-temperature molten salt tank 2, and the molten salt output end of the first channel of the second heat exchanger 6 is connected to the molten salt input end of the high-temperature molten salt tank 4; the steam input end of the second channel of the second heat exchanger 6 is connected to the reheat steam output end of the boiler in the coal-fired power generation system, and the steam output end of the second channel of the second heat exchanger 6 is connected to the steam input end of the low-pressure cylinder in the coal-fired power generation system; the first channel and the second channel of the second heat exchanger 6 exchange heat, so that the molten salt between the first intermediate-temperature molten salt tank 2 and the high-temperature molten salt tank 4 absorbs heat from the reheat steam of the coal-fired power generation system.

[0039] Understandably, since the first channel molten salt inlet of the second heat exchanger 6 is connected to the molten salt outlet of the first medium-temperature molten salt tank 2, and the first channel molten salt outlet of the second heat exchanger 6 is connected to the molten salt inlet of the high-temperature molten salt tank 4, the medium-temperature molten salt in the first medium-temperature molten salt tank 2 can enter the high-temperature molten salt tank 4 through the first channel of the second heat exchanger 6. Furthermore, since the second channel steam inlet of the second heat exchanger 6 is connected to the reheat steam outlet of the boiler in the coal-fired power generation system, and the second channel steam outlet of the second heat exchanger 6 is connected to the steam inlet of the low-pressure cylinder in the coal-fired power generation system, the reheat steam of the boiler can enter the low-pressure cylinder through the second channel of the second heat exchanger 6.

[0040] Therefore, by utilizing the heat exchange between the first and second channels in the second heat exchanger 6, the molten salt between the first medium-temperature molten salt tank 2 and the high-temperature molten salt tank 4 can absorb heat from the reheat steam of the coal-fired power generation system, thereby using the reheat steam to heat the molten salt, thereby improving the efficiency of the carbon capture coal-fired power plant and reducing the cost of the carbon capture coal-fired power plant.

[0041] The second heat exchanger 6 has a first channel and a second channel for direct or indirect heat exchange. The specific type of the second heat exchanger 6 can be set according to actual needs and is not restricted.

[0042] like Figure 1 As shown, in some embodiments, the energy storage system further includes a first regulating valve 10, which is disposed at the steam input end of the second channel of the second heat exchanger 6, and is used to regulate the heat absorbed by the molten salt between the first medium-temperature molten salt tank 2 and the high-temperature molten salt tank 4 from the reheat steam of the coal-fired power generation system.

[0043] It is understandable that, since the first regulating valve 10 is located at the steam input end of the second channel of the second heat exchanger 6, the first regulating valve 10 can adjust the opening of the second channel in the second heat exchanger 6, thereby adjusting the heat absorbed by the molten salt between the first medium-temperature molten salt tank 2 and the high-temperature molten salt tank 4 from the reheat steam of the coal-fired power generation system, thereby achieving safe and flexible operation of the power plant.

[0044] The specific type of the first regulating valve 10 can be set according to actual needs, and there are no restrictions on it.

[0045] like Figure 1As shown, in some embodiments, the energy storage system further includes a third heat exchanger 7. The first channel of the third heat exchanger 7 is disposed between the molten salt output end of the high-temperature molten salt tank 4 and the molten salt input end of the second medium-temperature molten salt tank 3, and the molten salt input end of the first channel of the third heat exchanger 7 is connected to the molten salt output end of the high-temperature molten salt tank 4, and the molten salt input end of the first channel of the third heat exchanger 7 is connected to the molten salt input end of the second medium-temperature molten salt tank 3; the condensate input end of the second channel of the third heat exchanger 7 is connected to the condensate output end of the desorption tower 200 in the carbon capture system, and the steam output end of the second channel of the third heat exchanger 7 is connected to the steam input end of the desorption tower 200 in the carbon capture system; the first channel and the second channel of the third heat exchanger 7 exchange heat to release heat from the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 to the condensate of the carbon capture system before the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 absorbs heat from the low-pressure cylinder inlet steam of the coal-fired power generation system.

[0046] Understandably, since the first channel molten salt inlet of the third heat exchanger 7 is connected to the molten salt outlet of the high-temperature molten salt tank 4, and the first channel molten salt outlet of the third heat exchanger 7 is connected to the molten salt inlet of the second medium-temperature molten salt tank 3, the high-temperature molten salt in the high-temperature molten salt tank 4 can enter the second medium-temperature molten salt tank 3 through the first channel of the third heat exchanger 7. Furthermore, since the second channel condensate inlet of the third heat exchanger 7 is connected to the condensate outlet of the desorption tower 200 in the carbon capture system, and the second channel steam outlet of the third heat exchanger 7 is connected to the steam inlet of the desorption tower 200 in the carbon capture system, the condensate of the desorption tower 200 can return to the desorption tower 200 through the second channel of the third heat exchanger 7.

[0047] Therefore, by utilizing the heat exchange between the first and second channels in the third heat exchanger 7, before the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 absorbs heat from the low-pressure cylinder inlet steam of the coal-fired power generation system, the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 releases heat to the condensate of the carbon capture system. This allows the molten salt to store heat and provide high-temperature steam to the absorption tower 100, thereby improving the efficiency of the carbon capture coal-fired power plant and reducing its cost.

[0048] The third heat exchanger 7 has a first channel and a second channel for direct or indirect heat exchange. The specific type of the third heat exchanger 7 can be set according to actual needs and there are no restrictions on it.

[0049] like Figure 1As shown, in some embodiments, the energy storage system further includes a fourth heat exchanger 8. The first channel of the fourth heat exchanger 8 is disposed between the molten salt output end of the high-temperature molten salt tank 4 and the molten salt input end of the second medium-temperature molten salt tank 3, and the molten salt input end of the first channel of the fourth heat exchanger 8 is connected to the molten salt output end of the high-temperature molten salt tank 4, and the molten salt input end of the first channel of the fourth heat exchanger 8 is connected to the molten salt input end of the second medium-temperature molten salt tank 3; the steam input end of the second channel of the fourth heat exchanger 8 is connected to the steam input end of the low-pressure cylinder in the coal-fired power generation system, and the condensate output end of the second channel of the fourth heat exchanger 8 is connected to the condensate input end of the deaerator in the coal-fired power generation system; the first and second channels of the fourth heat exchanger 8 exchange heat so that after the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 releases heat to the condensate of the carbon capture system, the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 absorbs heat from the inlet steam of the low-pressure cylinder of the coal-fired power generation system.

[0050] It is understandable that, since the first channel molten salt inlet of the fourth heat exchanger 8 is connected to the molten salt outlet of the high-temperature molten salt tank 4, and the first channel molten salt outlet of the fourth heat exchanger 8 is connected to the molten salt inlet of the second medium-temperature molten salt tank 3, the high-temperature molten salt in the high-temperature molten salt tank 4 can enter the second medium-temperature molten salt tank 3 through the first channel of the fourth heat exchanger 8. Furthermore, since the second channel steam inlet of the fourth heat exchanger 8 is connected to the steam inlet of the low-pressure cylinder in the coal-fired power generation system, and the second channel condensate outlet of the fourth heat exchanger 8 is connected to the condensate inlet of the deaerator in the coal-fired power generation system, the inlet steam of the low-pressure cylinder can enter the deaerator through the second channel of the fourth heat exchanger 8.

[0051] Therefore, by utilizing the heat exchange in the first and second channels of the fourth heat exchanger 8, after the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 releases heat to the condensate of the carbon capture system, the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 absorbs heat from the low-pressure cylinder inlet steam of the coal-fired power generation system. This allows the low-pressure cylinder inlet steam to heat the released high-temperature molten salt, thereby improving the efficiency of the carbon capture coal-fired power plant and reducing its cost.

[0052] The fourth heat exchanger 8 has a first channel and a second channel for direct or indirect heat exchange. The specific type of the fourth heat exchanger 8 can be set according to actual needs and is not restricted.

[0053] It should be noted that the first channel of the third heat exchanger 7 and the first channel of the fourth heat exchanger 8 are connected sequentially.

[0054] like Figure 1As shown, in some embodiments, the energy storage system further includes a second regulating valve 11, which is disposed at the steam input end of the second channel of the fourth heat exchanger 8, and is used to regulate the heat absorbed by the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 from the low-pressure cylinder inlet steam of the coal-fired power generation system.

[0055] It is understandable that, since the second regulating valve 11 is located at the steam input end of the second channel of the fourth heat exchanger 8, the second regulating valve 11 can adjust the opening of the second channel in the fourth heat exchanger 8, thereby adjusting the heat absorbed by the molten salt between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 from the low-pressure cylinder inlet steam of the coal-fired power generation system, thereby achieving safe and flexible operation of the power plant.

[0056] The specific type of the second regulating valve 11 can be set according to actual needs, and there are no restrictions on it.

[0057] like Figure 1 As shown, in some embodiments, the energy storage system further includes a fifth heat exchanger 9. The first channel of the fifth heat exchanger 9 is disposed between the molten salt output end of the second intermediate-temperature molten salt tank 3 and the molten salt input end of the cryogenic tank 1, and the molten salt input end of the first channel of the fifth heat exchanger 9 is connected to the molten salt output end of the second intermediate-temperature molten salt tank 3, and the molten salt output end of the first channel of the fifth heat exchanger 9 is connected to the molten salt input end of the cryogenic tank 1; the rich liquid input end of the second channel of the fifth heat exchanger 9 is connected to the rich liquid output end of the absorption tower 100 in the carbon capture system, and the rich liquid output end of the second channel of the fifth heat exchanger 9 is connected to the rich liquid input end of the desorption tower 200 in the carbon capture system; the first channel and the second channel of the fifth heat exchanger 9 exchange heat, so that the molten salt between the second intermediate-temperature molten salt tank 3 and the cryogenic tank 1 releases heat to the rich liquid of the carbon capture system.

[0058] Understandably, since the first channel molten salt inlet of the fifth heat exchanger 9 is connected to the molten salt outlet of the second medium-temperature molten salt tank 3, and the first channel molten salt outlet of the fifth heat exchanger 9 is connected to the molten salt inlet of the low-temperature tank 1, the medium-temperature molten salt in the second medium-temperature molten salt tank 3 can enter the low-temperature molten salt tank through the first channel of the fifth heat exchanger 9. Furthermore, since the second channel rich liquid inlet of the fifth heat exchanger 9 is connected to the rich liquid outlet of the absorption tower 100 in the carbon capture system, and the second channel rich liquid outlet of the fifth heat exchanger 9 is connected to the rich liquid inlet of the desorption tower 200 in the carbon capture system, the rich liquid of the absorption tower 100 can enter the desorption tower 200 through the second channel of the fifth heat exchanger 9.

[0059] Therefore, by utilizing the heat exchange between the first and second channels in the fifth heat exchanger 9, the molten salt between the second medium-temperature molten salt tank 3 and the low-temperature tank 1 releases heat to the rich liquid of the carbon capture system, thereby utilizing the heat storage of molten salt to achieve preheating of the rich liquid, thereby improving the efficiency of the carbon capture coal-fired power plant and reducing the cost of the carbon capture coal-fired power plant.

[0060] The fifth heat exchanger 9 has a first channel and a second channel for direct or indirect heat exchange. The specific type of the fifth heat exchanger 9 can be set according to actual needs and is not restricted.

[0061] like Figure 1 As shown, in some embodiments, the molten salt output terminal of the first medium-temperature molten salt tank 2 is connected to the molten salt input terminal of the second medium-temperature molten salt tank 3, and the molten salt input terminal of the first medium-temperature molten salt tank 2 is connected to the molten salt output terminal of the second medium-temperature molten salt tank 3.

[0062] It is understandable that, since the molten salt output end of the first medium-temperature molten salt tank 2 is connected to the molten salt input end of the second medium-temperature molten salt tank 3, and the molten salt input end of the first medium-temperature molten salt tank 2 is connected to the molten salt output end of the second medium-temperature molten salt tank 3, the first medium-temperature molten salt tank 2 and the second medium-temperature molten salt tank 3 can be connected to each other, thereby increasing the heat storage capacity and reducing the problem of insufficient heating capacity.

[0063] This disclosure also proposes an operation method for a large-scale carbon capture coal-fired power plant with integrated energy storage as described in this disclosure, including: Obtain the rated load (THA) and actual load of the coal-fired power generation system in the power plant; When the actual load of the coal-fired power generation system is greater than the rated load of the first proportion, the heat absorbed by the molten salt passage between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 in the power plant from the low-pressure cylinder steam input passage of the coal-fired power generation system is increased, and the heat absorbed by the molten salt passage between the first medium-temperature molten salt tank 2 and the high-temperature molten salt tank 4 in the power plant from the reheat steam passage of the coal-fired power generation system is decreased. When the actual load of the coal-fired power generation system is less than the rated load of the second proportion, the heat absorbed by the molten salt passage between the high-temperature molten salt tank 4 and the second medium-temperature molten salt tank 3 in the power plant from the low-pressure cylinder steam input passage of the coal-fired power generation system is reduced, and the heat absorbed by the molten salt passage between the first medium-temperature molten salt tank 2 and the high-temperature molten salt tank 4 in the power plant from the reheat steam passage of the coal-fired power generation system is increased. The second proportion is smaller than the first proportion.

[0064] For example, the first ratio could be 75%, and the second ratio could be 50%.

[0065] Specifically, the reheat steam and low-pressure cylinder inlet steam volume are controlled by controlling the first regulating valve 10 and the second regulating valve 11. The specific operating procedure is as follows: When the load of the coal-fired power plant is greater than 75% THA, the inlet pressure of the unit's low-pressure cylinder is between 0.4MPa and 0.55MPa. By increasing the opening of the second regulating valve 11 and decreasing the opening of the first regulating valve 10, the large-scale carbon capture system can operate while meeting various capture rates and improving the unit's efficiency. When the load of the coal-fired power plant is less than 50% THA, the inlet pressure of the unit's low-pressure cylinder is between 0.3MPa and 0.35MPa, which is insufficient to meet the needs of the carbon capture system. Therefore, by reducing or shutting down the second regulating valve 11 and increasing the opening of the first regulating valve 10, the large-scale carbon capture system can operate while meeting various capture rates and improving the unit's efficiency.

[0066] The carbon capture coal-fired power plant of this embodiment has at least the following advantages: The desorption tower 200 in the carbon capture system requires steam with high flow rate (approximately 120 kJ / s) and low quality (temperature range of 120℃-140℃). By installing a third heat exchanger 7, the characteristics of molten salt can be utilized to provide the required steam and reduce the steam consumption of the unit.

[0067] A three-stage molten salt tank is adopted. The high-temperature molten salt provides the steam required by the desorption tower 200, the medium-temperature molten salt storage tank provides the heat required by the rich liquid, and the heat in the lean liquid is transferred to the medium-temperature molten salt, realizing the cascade utilization of energy.

[0068] By controlling the amount of reheat steam and low-pressure cylinder inlet steam, a rapid response to load changes can be achieved. At low loads, the reheat steam flow rate can be increased to achieve carbon-electric decoupling.

[0069] It should be noted that in the description of this disclosure, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0070] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of preferred embodiments of this disclosure includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this disclosure pertain.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] Although embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A large-scale carbon capture coal-fired power plant with integrated energy storage, characterized in that, include: Coal-fired power generation systems, carbon capture systems, and energy storage systems; The energy storage system includes: a cryogenic tank, a first intermediate-temperature molten salt tank, a high-temperature molten salt tank, and a second intermediate-temperature molten salt tank; The molten salt output end of the cryogenic tank is connected to the molten salt input end of the first medium-temperature molten salt tank, and the molten salt passage between the cryogenic tank and the first medium-temperature molten salt tank is used to absorb heat from the lean liquid circulation passage of the carbon capture system. The molten salt output end of the first medium-temperature molten salt tank is connected to the molten salt input end of the high-temperature molten salt tank, and the molten salt passage between the first medium-temperature molten salt tank and the high-temperature molten salt tank is used to absorb heat from the reheat steam passage of the coal-fired power generation system. The molten salt output end of the high-temperature molten salt tank is connected to the molten salt input end of the second medium-temperature molten salt tank, and the molten salt passage between the high-temperature molten salt tank and the second medium-temperature molten salt tank is used to release heat to the steam heating passage of the carbon capture system, and then absorb heat from the low-pressure cylinder steam input passage of the coal-fired power generation system. The molten salt output end of the second medium-temperature molten salt tank is connected to the molten salt input end of the low-temperature tank, and the molten salt passage between the second medium-temperature molten salt tank and the low-temperature tank is used to release heat to the rich liquid circulation passage of the carbon capture system.

2. The large-scale carbon capture coal-fired power plant with integrated energy storage according to claim 1, characterized in that, The energy storage system also includes: First heat exchanger; The first channel of the first heat exchanger is located between the molten salt output end of the low-temperature tank and the molten salt input end of the first medium-temperature molten salt tank, and the molten salt input end of the first channel of the first heat exchanger is connected to the molten salt output end of the low-temperature tank, and the molten salt output end of the first channel of the first heat exchanger is connected to the molten salt input end of the first medium-temperature molten salt tank. The second channel of the first heat exchanger is connected to the lean liquid input end of the desorption tower in the carbon capture system, and the second channel of the first heat exchanger is connected to the lean liquid input end of the absorption tower in the carbon capture system. The first and second channels of the first heat exchanger exchange heat so that the molten salt between the cryogenic tank and the first intermediate-temperature molten salt tank absorbs heat from the lean solution of the carbon capture system.

3. The large-scale carbon capture coal-fired power plant with integrated energy storage according to claim 1, characterized in that, The energy storage system also includes: Second heat exchanger; The first channel of the second heat exchanger is located between the molten salt output end of the first medium-temperature molten salt tank and the molten salt input end of the high-temperature molten salt tank, and the molten salt input end of the first channel of the second heat exchanger is connected to the molten salt output end of the first medium-temperature molten salt tank, and the molten salt output end of the first channel of the second heat exchanger is connected to the molten salt input end of the high-temperature molten salt tank. The second heat exchanger's second channel steam inlet is connected to the reheat steam outlet of the boiler in the coal-fired power generation system, and the second heat exchanger's second channel steam outlet is connected to the steam inlet of the low-pressure cylinder in the coal-fired power generation system. The first and second channels of the second heat exchanger exchange heat so that the molten salt between the first medium-temperature molten salt tank and the high-temperature molten salt tank absorbs heat from the reheat steam of the coal-fired power generation system.

4. The large-scale carbon capture coal-fired power plant with integrated energy storage according to claim 3, characterized in that, The energy storage system also includes: A first regulating valve is disposed at the steam inlet of the second channel of the second heat exchanger, and the first regulating valve is used to regulate the heat absorbed by the molten salt between the first medium-temperature molten salt tank and the high-temperature molten salt tank from the reheat steam of the coal-fired power generation system.

5. The large-scale carbon capture coal-fired power plant with integrated energy storage according to claim 1, characterized in that, The energy storage system also includes: Third heat exchanger; The first channel of the third heat exchanger is located between the molten salt output end of the high-temperature molten salt tank and the molten salt input end of the second medium-temperature molten salt tank, and the molten salt input end of the first channel of the third heat exchanger is connected to the molten salt output end of the high-temperature molten salt tank, and the molten salt output end of the first channel of the third heat exchanger is connected to the molten salt input end of the second medium-temperature molten salt tank. The second channel condensate inlet of the third heat exchanger is connected to the condensate outlet of the desorption tower in the carbon capture system, and the second channel steam outlet of the third heat exchanger is connected to the steam inlet of the desorption tower in the carbon capture system. The first and second channels of the third heat exchanger exchange heat to release heat from the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank to the condensate of the carbon capture system before the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank absorbs heat from the low-pressure cylinder inlet steam of the coal-fired power generation system.

6. The large-scale carbon capture coal-fired power plant with integrated energy storage according to claim 1, characterized in that, The energy storage system also includes: Fourth heat exchanger; The first channel of the fourth heat exchanger is located between the molten salt output end of the high-temperature molten salt tank and the molten salt input end of the second medium-temperature molten salt tank, and the molten salt input end of the first channel of the fourth heat exchanger is connected to the molten salt output end of the high-temperature molten salt tank, and the molten salt output end of the first channel of the fourth heat exchanger is connected to the molten salt input end of the second medium-temperature molten salt tank. The second channel steam inlet of the fourth heat exchanger is connected to the steam inlet of the low-pressure cylinder in the coal-fired power generation system, and the second channel condensate outlet of the fourth heat exchanger is connected to the condensate inlet of the deaerator in the coal-fired power generation system. The first and second channels of the fourth heat exchanger exchange heat so that after the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank releases heat to the condensate of the carbon capture system, the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank absorbs heat from the low-pressure cylinder inlet steam of the coal-fired power generation system.

7. The large-scale carbon capture coal-fired power plant with integrated energy storage according to claim 6, characterized in that, The energy storage system also includes: The second regulating valve is located at the steam inlet of the second channel of the fourth heat exchanger, and is used to regulate the heat absorbed by the molten salt between the high-temperature molten salt tank and the second medium-temperature molten salt tank from the low-pressure cylinder inlet steam of the coal-fired power generation system.

8. The large-scale carbon capture coal-fired power plant with integrated energy storage according to claim 1, characterized in that, The energy storage system also includes: Fifth heat exchanger; The first channel of the fifth heat exchanger is located between the molten salt output end of the second medium-temperature molten salt tank and the molten salt input end of the low-temperature tank, and the molten salt input end of the first channel of the fifth heat exchanger is connected to the molten salt output end of the second medium-temperature molten salt tank, and the molten salt output end of the first channel of the fifth heat exchanger is connected to the molten salt input end of the low-temperature tank. The second channel of the fifth heat exchanger is connected to the rich liquid input end of the absorption tower in the carbon capture system, and the second channel of the fifth heat exchanger is connected to the rich liquid input end of the desorption tower in the carbon capture system. The first and second channels of the fifth heat exchanger exchange heat so that the molten salt between the second medium-temperature molten salt tank and the low-temperature tank releases heat to the rich liquid of the carbon capture system.

9. The large-scale carbon capture coal-fired power plant with integrated energy storage according to claim 1, characterized in that, The molten salt output terminal of the first medium-temperature molten salt tank is connected to the molten salt input terminal of the second medium-temperature molten salt tank, and the molten salt input terminal of the first medium-temperature molten salt tank is connected to the molten salt output terminal of the second medium-temperature molten salt tank.

10. An operation method for a large-scale carbon capture coal-fired power plant with integrated energy storage as described in any one of claims 1-9, characterized in that, include: Obtain the rated load and actual load of the coal-fired power generation system in the power plant; When the actual load of the coal-fired power generation system is greater than the rated load of the first proportion, the heat absorbed by the molten salt passage between the high-temperature molten salt tank and the second medium-temperature molten salt tank in the power plant from the low-pressure cylinder steam input passage of the coal-fired power generation system is increased, and the heat absorbed by the molten salt passage between the first medium-temperature molten salt tank and the high-temperature molten salt tank in the power plant from the reheat steam passage of the coal-fired power generation system is decreased. When the actual load of the coal-fired power generation system is less than the rated load of the second proportion, the heat absorbed by the molten salt passage between the high-temperature molten salt tank and the second medium-temperature molten salt tank in the power plant from the low-pressure cylinder steam input passage of the coal-fired power generation system is reduced, and the heat absorbed by the molten salt passage between the first medium-temperature molten salt tank and the high-temperature molten salt tank in the power plant from the reheat steam passage of the coal-fired power generation system is increased. The second ratio is smaller than the first ratio.

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