Integrated supercritical and transcritical compression carbon dioxide energy storage power unit

Abstract

The application discloses a thermal power generating unit integrating supercritical and transcritical compression carbon dioxide energy storage, wherein the outlet of a low-pressure cylinder is connected with the primary side of a first heat exchanger through a condenser; the outlet of a first compressor is connected with the inlet of a first expander in sequence through the secondary side of the first heat exchanger, a first high-pressure storage tank, the primary side of a second heat exchanger and the secondary side of a third heat exchanger; the outlet of the first expander is connected with the inlet of a chemical absorption carbon dioxide low-pressure storage tank through the secondary side of the second heat exchanger; the gas outlet of the chemical absorption carbon dioxide low-pressure storage tank is connected with the inlet of the first compressor; the outlet of a second compressor is connected with the inlet of a second expander in sequence through a first heat exchange pipe, a second high-pressure storage tank, a second heat exchange pipe and the secondary side of a fourth heat exchanger; and the energy storage density of the unit can be improved under the premise of ensuring the stability of the energy storage system of the thermal power generating unit, and energy efficient utilization is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of comprehensive utilization of thermal energy, and relates to a thermal power generating unit integrating supercritical and transcritical compression of carbon dioxide energy storage. BACKGROUND

[0002] With the rapid development of new energy and the change of power grid structure, in order to effectively ensure the comprehensive utilization of energy and the ultra-high voltage power transmission capacity, the peak shaving capacity of the thermal power generating unit is put forward to a severe test. The waste heat of the thermal power generating unit is used to provide energy for the energy storage system, realize the comprehensive utilization of thermal energy, and the introduction of the energy storage system can also enhance the peak shaving flexibility of the thermal power generating unit. Therefore, the compressed carbon dioxide energy storage system established by means of the thermal power generating unit is the best choice.

[0003] Compared with compressed air energy storage, carbon dioxide has the characteristics of high density, low viscosity and mild critical point, high cycle efficiency and large energy storage density, and is the current research focus. Carbon dioxide is a greenhouse gas, and the process of capturing carbon dioxide is complex, so a closed cycle is required. In order to meet the demand of large-scale energy storage construction, liquefied storage is proposed to improve the energy storage density, but the energy consumption level of the liquefaction equipment is high, and the storage tank has cold brittleness. Therefore, the energy storage density and stability of the energy storage system are crucial. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a thermal power generating unit integrating supercritical and transcritical compression of carbon dioxide energy storage, which can improve the energy storage density under the premise of ensuring the stability of the energy storage system of the thermal power generating unit, and realize efficient energy utilization.

[0005] In order to achieve the above purpose, the present application discloses a thermal power generating unit integrating supercritical and transcritical compression of carbon dioxide energy storage, which comprises a low-pressure cylinder, a condenser, a first heat exchanger, a first compressor, a first high-pressure storage tank, a second heat exchanger, a third heat exchanger, a first expander, a chemical absorption carbon dioxide low-pressure storage tank, a second compressor, a second high-pressure storage tank, a fourth heat exchanger and a second expander.

[0006] The outlet of the low-pressure cylinder is connected to the condenser and the primary side of the first heat exchanger, the outlet of the first compressor is connected to the secondary side of the first heat exchanger, the first high-pressure storage tank, the primary side of the second heat exchanger and the secondary side of the third heat exchanger in sequence, and the inlet of the first expander, the outlet of the first expander is connected to the secondary side of the second heat exchanger and the inlet of the chemical absorption carbon dioxide low-pressure storage tank, and the gas outlet of the chemical absorption carbon dioxide low-pressure storage tank is connected to the inlet of the first compressor.

[0007] The chemical absorption carbon dioxide low-pressure storage tank is provided with a first heat exchange pipe and a second heat exchange pipe; the outlet of the second compressor is connected in sequence with the first heat exchange pipe, the second high-pressure storage tank, the second heat exchange pipe, the secondary side of the fourth heat exchanger, and the inlet of the second expander; and the outlet of the second expander is connected with the inlet of the second compressor.

[0008] The boiler feed water pipeline, the boiler, the back pressure turbine, the high-pressure cylinder, the medium-pressure cylinder, and the low-pressure cylinder are further included.

[0009] The outlet of the boiler feed water pipeline is connected with the inlet of the boiler; the main steam outlet of the boiler is connected with the inlet of the back pressure turbine and the inlet of the high-pressure cylinder; the outlet of the high-pressure cylinder is connected with the reheated side inlet of the boiler; the reheated side outlet of the boiler is connected with the inlet of the medium-pressure cylinder, the primary side inlet of the third heat exchanger, and the primary side inlet of the fourth heat exchanger; the outlet of the medium-pressure cylinder is connected with the inlet of the low-pressure cylinder; and the outlet of the low-pressure cylinder is connected with the primary side of the first heat exchanger through the condenser and the condensate pump.

[0010] The output shaft of the back pressure turbine is connected with the driving shaft of the first compressor.

[0011] The gas-liquid separator is further included.

[0012] The gas outlet of the chemical absorption carbon dioxide low-pressure storage tank is connected with the inlet of the gas-liquid separator; the gas outlet of the gas-liquid separator is connected with the inlet of the first compressor; and the liquid outlet of the gas-liquid separator is connected with the inlet of the chemical absorption carbon dioxide low-pressure storage tank.

[0013] The chemical absorption carbon dioxide low-pressure storage tank is further provided with a spraying layer; the chemical absorption carbon dioxide low-pressure storage tank is filled with a carbon dioxide chemical absorbent; the first heat exchange pipe and the second heat exchange pipe are located in the carbon dioxide chemical absorbent; and the circulating liquid outlet of the chemical absorption carbon dioxide low-pressure storage tank is connected with the inlet of the spraying layer.

[0014] The first expander is further included, and the first expander is connected with the second generator.

[0015] The second expander is further included, and the second expander is connected with the third generator.

[0016] The first generator and the clutch-gear box are further included, and the high-pressure cylinder, the medium-pressure cylinder, the low-pressure cylinder, the first generator, the clutch-gear box, and the second compressor are connected in sequence.

[0017] The outlet of the second high-pressure storage tank is connected with the inlet of the second expander through the second heat exchange pipe, the primary side of the fifth heat exchanger, and the secondary side of the fourth heat exchanger.

[0018] The outlet of the second expander is connected with the inlet of the second compressor through the secondary side of the fifth heat exchanger and the low-pressure gas storage tank.

[0019] The present application has the following beneficial effects:

[0020] The integrated supercritical and transcritical carbon dioxide compression energy storage thermal power generating unit in the present application combines transcritical and supercritical carbon dioxide compression energy storage to improve the energy storage density and peak shaving capacity of the thermal power generating unit, fully comprehensively utilizes the heat in the energy storage and energy release processes to improve the operation efficiency and flexibility of the unit, meanwhile, the first heat exchanger is used to collect the compression heat and heat the condensate water to improve the condensate water temperature, reduce the heat exchange irreversible loss, improve the energy efficiency of the unit, in addition, the chemical absorption low-pressure storage is used to replace the liquefied carbon dioxide storage tank, the energy storage density is considerable, the stability is higher than that of the liquefied carbon dioxide energy storage system, the energy consumption is low, the cost is reduced, and the compression heat in the supercritical carbon dioxide compression energy storage system and the supercritical carbon dioxide in the energy release stage are used as the heat source and cold source of the chemical absorption carbon dioxide low-pressure storage tank in the energy storage and energy release stages respectively, the comprehensive utilization of energy is realized, and the overall operation efficiency of the energy storage system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present application.

[0022] 1 is a boiler, 2 is a high-pressure cylinder, 3 is a medium-pressure cylinder, 4 is a low-pressure cylinder, 5 is a first generator, 6 is a condenser, 7 is a condensate pump, 8 is a first heat exchanger, 9 is a first compressor, 10 is a first high-pressure storage tank, 11 is a second heat exchanger, 12 is a third heat exchanger, 13 is a first expander, 14 is a second generator, 15 is a chemical absorption carbon dioxide low-pressure storage tank, 16 is a gas-liquid separator, 17 is a back-pressure steam turbine, 18 is a clutch-gearbox, 19 is a second compressor, 20 is a low-pressure gas storage tank, 21 is a fourth heat exchanger, 22 is a second expander, 23 is a third generator, 24 is a fifth heat exchanger, and 25 is a second high-pressure storage tank. DETAILED DESCRIPTION

[0023] In order to enable personnel in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments, and are not intended to limit the scope of the present application. In addition, in the following description, the description of the known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should belong to the scope of protection of the present application.

[0024] The structural schematic diagram according to the disclosed embodiment of the present application is shown in the accompanying drawings. The drawings are not drawn to scale, in which some details are exaggerated for the purpose of clear expression, and some details can be omitted. The shapes of various regions, layers and the relative size and position relationship therebetween shown in the drawings are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and a person skilled in the art can additionally design regions / layers with different shapes, sizes and relative positions according to actual needs.

[0025] Reference Figure 1 The integrated supercritical and transcritical carbon dioxide compression power generating unit for energy storage according to the present application comprises a boiler 1, a high-pressure cylinder 2, a medium-pressure cylinder 3, a low-pressure cylinder 4, a first generator 5, a condenser 6, a condensate pump 7, a first heat exchanger 8, a first compressor 9, a first high-pressure storage tank 10, a second heat exchanger 11, a third heat exchanger 12, a first expander 13, a second generator 14, a chemical absorption carbon dioxide low-pressure storage tank 15, a gas-liquid separator 16, a back-pressure steam turbine 17, a clutch-gearbox 18, a second compressor 19, a low-pressure gas storage tank 20, a fourth heat exchanger 21, a second expander 22, a third generator 23, a fifth heat exchanger 24 and a second high-pressure storage tank 25.

[0026] The outlet of a boiler feedwater pipe is connected to the inlet of the boiler 1, the main steam outlet of the boiler 1 is connected to the inlet of the back-pressure steam turbine 17 and the inlet of the high-pressure cylinder 2, the outlet of the high-pressure cylinder 2 is connected to the reheated side inlet of the boiler 1, the reheated side outlet of the boiler 1 is connected to the inlet of the medium-pressure cylinder 3, the primary side inlet of the third heat exchanger 12 and the primary side inlet of the fourth heat exchanger 21, the outlet of the medium-pressure cylinder 3 is connected to the inlet of the low-pressure cylinder 4, and the outlet of the low-pressure cylinder 4 is connected to the primary side of the first heat exchanger 8 through the condenser 6 and the condensate pump 7.

[0027] The output shaft of the back-pressure steam turbine 17 is connected to the driving shaft of the first compressor 9, the outlet of the first compressor 9 is connected to the inlet of the first expander 13 in sequence through the secondary side of the first heat exchanger 8, the first high-pressure storage tank 10, the primary side of the second heat exchanger 11 and the secondary side of the third heat exchanger 12, the outlet of the first expander 13 is connected to the inlet of the chemical absorption carbon dioxide low-pressure storage tank 15 through the secondary side of the second heat exchanger 11, the gas outlet of the chemical absorption carbon dioxide low-pressure storage tank 15 is connected to the inlet of the gas-liquid separator 16, the gas outlet of the gas-liquid separator 16 is connected to the inlet of the first compressor 9, and the liquid outlet of the gas-liquid separator 16 is connected to the inlet of the chemical absorption carbon dioxide low-pressure storage tank 15.

[0028] The chemical absorption carbon dioxide low-pressure storage tank 15 is provided with a first heat exchange pipe, a second heat exchange pipe and a spraying layer, the chemical absorption carbon dioxide low-pressure storage tank 15 is provided with a carbon dioxide chemical absorption agent, the carbon dioxide chemical absorption agent can be ethanol amine, the first heat exchange pipe and the second heat exchange pipe are located in the carbon dioxide chemical absorption agent, and the circulation liquid outlet of the chemical absorption carbon dioxide low-pressure storage tank 15 is communicated with the inlet of the spraying layer.

[0029] The outlet of the second compressor 19 is communicated with the inlet of the second high-pressure storage tank 25 through the first heat exchange pipe, the outlet of the second high-pressure storage tank 25 is communicated with the inlet of the second expander 22 through the second heat exchange pipe, the primary side of the fifth heat exchanger 24 and the secondary side of the fourth heat exchanger 21, and the outlet of the second expander 22 is communicated with the inlet of the second compressor 19 through the secondary side of the fifth heat exchanger 24 and the low-pressure gas storage tank 20.

[0030] The first expander 13 is connected with the second generator 14, the second expander 22 is connected with the third generator 23, the high-pressure cylinder 2, the medium-pressure cylinder 3, the low-pressure cylinder 4, the first generator 5, the clutch-gear box 18 and the second compressor 19 are sequentially connected.

[0031] The number of the third heat exchanger 12 and the first expander 13 is the same, the number of the first heat exchanger 8 and the first compressor 9 is the same, the chemical absorption carbon dioxide low-pressure storage tank 15 can be one or multiple, the number of the second compressor 19 and the chemical absorption carbon dioxide low-pressure storage tank 15 is the same, and the number of the fourth heat exchanger 21 and the second expander 22 is the same.

[0032] The working principle of the application is as follows:

[0033] The energy storage process is as follows: the coal-fired generator set is normally operated, the transcritical and supercritical carbon dioxide compression energy storage system is simultaneously operated, the first generator 5 drives the second compressor 19 through the clutch-gear box 18, the carbon dioxide output from the low-pressure gas storage tank 20 is compressed, the compression heat is absorbed by the chemical absorption carbon dioxide low-pressure storage tank 15, and the cooled carbon dioxide is stored in the second high-pressure storage tank 25; the chemical absorption carbon dioxide low-pressure storage tank 15 releases carbon dioxide after absorbing the compression heat of the second compressor 19, the carbon dioxide is separated by the gas-liquid separator 16 and then enters the first compressor 9, part of the main steam of the boiler 1 drives the back pressure turbine 17, the back pressure turbine 17 drives the first compressor 9 to compress the carbon dioxide to supercritical, so as to form supercritical carbon dioxide, and the supercritical carbon dioxide is cooled by the condensed water of the first heat exchanger 8 and then stored in the first high-pressure storage tank 10.

[0034] The energy releasing process is as follows: the coal-fired generator set is in normal operation, the supercritical carbon dioxide output from the first high-pressure storage tank 10 is heated by the exhaust steam of the first expander 13 in the second heat exchanger 11, the heated supercritical carbon dioxide is heated by the partial reheat steam output from the boiler 1 in the third heat exchanger 12, and then enters the first expander 13 to do work to drive the second generator 14 to generate electricity; the carbon dioxide after work passes through the second heat exchanger 11 to be cooled, and is stored in the chemical absorption carbon dioxide low-pressure storage tank 15, the chemical absorption storage process generates heat, the heat is absorbed by the carbon dioxide released from the second high-pressure storage tank 25, the carbon dioxide is preheated by the fifth heat exchanger 24 and reheated by the fourth heat exchanger 21, and then enters the second expander 22 to do work to drive the third generator 23 to generate electricity, and the exhaust steam of the second expander 22 is cooled by the fifth heat exchanger 24 and stored in the low-pressure storage tank 20.

[0035] The present application has the following characteristics:

[0036] 1) The present application combines transcritical and supercritical compressed carbon dioxide energy storage to improve the energy storage density and peak shaving capacity of the thermal power generating unit, fully utilizes the heat of the energy storage and energy releasing process to improve the operation efficiency and flexibility of the unit.

[0037] 2) The energy releasing stage adopts the exhaust steam of the expander to heat the reheat steam to heat the carbon dioxide, which avoids increasing the equipment to collect the compression heat to heat the carbon dioxide in the energy releasing stage, and improves the economy of the unit.

[0038] 3) The energy storage stage utilizes the main steam to drive the back pressure turbine 17 to drive the first compressor 9 to operate, and utilizes the first generator 5 to drive the second compressor 19 to improve the compression capacity and effectively reduce the power consumption of the energy storage system.

[0039] 4) The first heat exchanger 8 is used to collect the compression heat, and the collected compression heat is used to heat the condensed water to improve the condensed water temperature, reduce the irreversible loss of heat exchange, and improve the energy efficiency of the unit; the reheat steam is used to heat the high-pressure and low-temperature carbon dioxide in the transcritical compressed carbon dioxide energy storage system in the energy releasing stage to improve the work capacity of the carbon dioxide and increase the energy storage power generation capacity of the unit.

[0040] 5) The chemical absorption low-pressure storage is used to replace the liquefied carbon dioxide storage tank, the energy storage density is considerable, the stability of the transcritical compressed carbon dioxide energy storage system is high, the energy consumption is low, and the cost is reduced.

[0041] 6) The compression heat of the supercritical compressed carbon dioxide energy storage system in the energy storage stage and the supercritical carbon dioxide in the energy releasing stage are used as the heat source and cold source of the chemical absorption carbon dioxide low-pressure storage tank 15 in the energy storage and energy releasing stages respectively, the energy is comprehensively utilized, and the overall operation efficiency of the energy storage system is improved.

[0042] 7) The application realizes the reasonable cascade utilization of energy by integrating the supercritical and transcritical compressed carbon dioxide energy storage system with the thermal power unit, compared with the conventional compressed carbon dioxide energy storage and liquid compressed carbon dioxide energy storage system, the overall operation efficiency and peak shaving flexibility of the thermal power unit are improved.

[0043] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific embodiments of the present application can still be modified or replaced by the equivalent, without departing from the spirit and scope of the present application, any modification or equivalent replacement, which should be covered within the protection scope of the claims of the present application.

Claims

1. A thermal power generating unit integrating supercritical and transcritical compression of carbon dioxide for energy storage, characterized in that, The system comprises a low-pressure cylinder (4), a condenser (6), a first heat exchanger (8), a first compressor (9), a first high-pressure storage tank (10), a second heat exchanger (11), a third heat exchanger (12), a first expander (13), a chemical absorption carbon dioxide low-pressure storage tank (15), a second compressor (19), a second high-pressure storage tank (25), a fourth heat exchanger (21) and a second expander (22); An outlet of the low-pressure cylinder (4) is connected to a primary side of the first heat exchanger (8) through the condenser (6), an outlet of the first compressor (9) is connected to an inlet of the first expander (13) through a secondary side of the first heat exchanger (8), the first high-pressure storage tank (10), a primary side of the second heat exchanger (11) and a secondary side of the third heat exchanger (12) in sequence, an outlet of the first expander (13) is connected to an inlet of the chemical absorption carbon dioxide low-pressure storage tank (15) through a secondary side of the second heat exchanger (11), and a gas outlet of the chemical absorption carbon dioxide low-pressure storage tank (15) is connected to an inlet of the first compressor (9). The chemical absorption carbon dioxide low-pressure storage tank (15) is provided with a first heat exchange pipe and a second heat exchange pipe, an outlet of the second compressor (19) is connected to an inlet of the second expander (22) through the first heat exchange pipe, the second high-pressure storage tank (25), the second heat exchange pipe and a secondary side of the fourth heat exchanger (21) in sequence, and an outlet of the second expander (22) is connected to an inlet of the second compressor (19).

2. The integrated supercritical and transcritical carbon dioxide compressed energy storage fossil power plant of claim 1, wherein, The system further comprises a boiler feedwater pipeline, a boiler (1), a back pressure turbine (17), a high-pressure cylinder (2), a medium-pressure cylinder (3) and the low-pressure cylinder (4). An outlet of the boiler feedwater pipeline is connected to an inlet of the boiler (1), a main steam outlet of the boiler (1) is connected to an inlet of the back pressure turbine (17) and an inlet of the high-pressure cylinder (2), an outlet of the high-pressure cylinder (2) is connected to an inlet of a reheating side of the boiler (1), an outlet of the reheating side of the boiler (1) is connected to an inlet of the medium-pressure cylinder (3), a primary side inlet of the third heat exchanger (12) and a primary side inlet of the fourth heat exchanger (21), an outlet of the medium-pressure cylinder (3) is connected to an inlet of the low-pressure cylinder (4), and an outlet of the low-pressure cylinder (4) is connected to a primary side of the first heat exchanger (8) through the condenser (6) and a condensate pump (7).

3. The integrated supercritical and transcritical carbon dioxide compressed energy storage fossil power plant of claim 2, wherein, An output shaft of the back pressure turbine (17) is connected to a driving shaft of the first compressor (9).

4. The integrated supercritical and transcritical carbon dioxide compressed energy storage fossil power plant of claim 1, wherein, The system further comprises a gas-liquid separator (16). A gas outlet of the chemical absorption carbon dioxide low-pressure storage tank (15) is connected to an inlet of the gas-liquid separator (16), a gas outlet of the gas-liquid separator (16) is connected to an inlet of the first compressor (9), and a liquid outlet of the gas-liquid separator (16) is connected to an inlet of the chemical absorption carbon dioxide low-pressure storage tank (15).

5. The integrated supercritical and transcritical carbon dioxide compressed energy storage fossil power plant of claim 1, wherein, The chemical absorption carbon dioxide low-pressure storage tank (15) is further provided with a spraying layer, the chemical absorption carbon dioxide low-pressure storage tank (15) contains a carbon dioxide chemical absorbent, the first heat exchange pipe and the second heat exchange pipe are located in the carbon dioxide chemical absorbent, and a circulating liquid outlet of the chemical absorption carbon dioxide low-pressure storage tank (15) is connected to an inlet of the spraying layer.

6. The integrated supercritical and transcritical carbon dioxide compressed energy storage fossil power plant of claim 2, wherein, A first expander (13) is further included, which is connected with a second generator (14).

7. The integrated supercritical and transcritical carbon dioxide compressed energy storage fossil power plant of claim 2, wherein, A second expander (22) is further included, which is connected with a third generator (23).

8. The integrated supercritical and transcritical carbon dioxide compressed energy storage fossil power plant of claim 2, wherein, A first generator (5) and a clutch-gear box (18) are further included, and the high-pressure cylinder (2), the medium-pressure cylinder (3), the low-pressure cylinder (4), the first generator (5), the clutch-gear box (18) and the second compressor (19) are sequentially connected.

9. The integrated supercritical and transcritical carbon dioxide compressed energy storage fossil power plant of claim 2, wherein, The outlet of the second high-pressure storage tank (25) is connected with the inlet of the second expander (22) through the second heat exchange pipe, the primary side of the fifth heat exchanger (24) and the secondary side of the fourth heat exchanger (21).

10. The integrated supercritical and transcritical carbon dioxide compressed energy storage fossil power plant of claim 9, wherein, The outlet of the second expander (22) is connected with the inlet of the second compressor (19) through the secondary side of the fifth heat exchanger (24) and the low-pressure gas storage tank (20).

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