System and method for coupling coal-fired power CCUS carbon capture with adsorption-based carbon dioxide energy storage

Abstract

The present invention discloses a system and method for coal-fired power CCUS carbon capture coupled adsorption carbon dioxide energy storage. The system includes a CCUS carbon dioxide reduction device, a third heat exchanger, a compressor, a fourth heat exchanger and a high-pressure liquefied storage tank connected in sequence along the flow direction, the input end of the CCUS carbon dioxide reduction device is connected to the boiler exhaust flue gas line; the output end of the high-pressure liquefied storage tank is connected to the liquefied carbon dioxide output line; the compressor, the fourth heat exchanger and the high-pressure liquefied storage tank are connected in parallel with a carbon dioxide low-pressure adsorption long-term energy storage system, and the carbon dioxide low-pressure adsorption long-term energy storage system flows from the downstream of the high-pressure liquefied storage tank to the upstream of the compressor; a valve is provided downstream of the high-pressure liquefied storage tank. It can improve the peak output, deep peak regulation capability and rapid load change capability of coal-fired power units, realize the non-stop zero power supply operation of coal-fired power units, and bring considerable economic and social benefits to power plants.

Description

Technical Field

[0001] The present invention relates to the technical field of energy utilization of coal-fired power units, in particular to a system and method for coal-fired power CCUS carbon capture coupled with adsorption-type carbon dioxide energy storage. Background Art

[0002] Under the background of "dual carbon", with the increase in the power generation of renewable energy sources such as wind power and solar energy, which are intermittent and unstable, and the phenomenon of wind curtailment and light curtailment still remaining high, the power grid has higher and higher requirements for the peak load output and deep peak shaving ability of coal-fired power units. At present, coal-fired power units cannot achieve long-term deep peak shaving or zero-power supply operation without shutting down. Limited by the maximum evaporation capacity of the boiler, the peak load capacity in summer is also relatively limited; at the same time, significant carbon emission reduction cannot be achieved by improving the efficiency of the unit, and the CCUS carbon capture system is still one of the main means. Summary of the Invention

[0003] The object of the present invention is to provide a system and method for coal-fired power CCUS carbon capture coupled with adsorption-type carbon dioxide energy storage to solve the above problems, which can improve the peak load output, deep peak shaving ability and rapid load change ability of coal-fired power units, realize zero-power supply operation of coal-fired power units without shutting down, and bring considerable economic and social benefits to the power plant.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A system for coal-fired power CCUS carbon capture coupled with adsorption-type carbon dioxide energy storage includes a CCUS carbon dioxide reduction device, a third heat exchanger, a compressor, a fourth heat exchanger and a high-pressure liquefied storage tank connected in sequence along the flow direction. The input end of the CCUS carbon dioxide reduction device is connected to the boiler flue gas line; the output end of the high-pressure liquefied storage tank is connected to the liquefied carbon dioxide output line; the compressor, the fourth heat exchanger and the high-pressure liquefied storage tank are jointly connected in parallel with a carbon dioxide low-pressure adsorption-type long-term energy storage system, and the carbon dioxide low-pressure adsorption-type long-term energy storage system flows from the downstream of the high-pressure liquefied storage tank to the upstream of the compressor; a valve is provided downstream of the high-pressure liquefied storage tank to respectively adjust the flow rates to the liquefied carbon dioxide output line and the carbon dioxide low-pressure adsorption-type long-term energy storage system.

[0006] Optionally, the carbon dioxide low-pressure adsorption-type long-term energy storage system includes a sixth heat exchanger, a turbine and an adsorption tower connected in sequence along the flow direction; the adsorption tower is also bidirectionally connected with a fifth heat exchanger and a first heat exchanger.

[0007] Optionally, the first heat exchanger is bidirectionally connected with a second heat exchanger.

[0008] Optionally, the fourth heat exchanger and the CCUS carbon dioxide reduction device are in two-way communication; the third heat exchanger and the second heat exchanger are in two-way communication with the steam turbine condensate line; the fifth heat exchanger and the sixth heat exchanger are in two-way communication with the boiler high-temperature flue gas line or the steam turbine high-temperature steam line; the first heat exchanger is in two-way communication with the steam turbine feed water line.

[0009] Optionally, the fifth heat exchanger and the sixth heat exchanger are in two-way communication with the same boiler high-temperature flue gas line or the steam turbine high-temperature steam line.

[0010] The method for coupling coal-fired power CCUS carbon capture with adsorption-type carbon dioxide energy storage includes the following switchable modes:

[0011] Mode 1, carbon capture to produce liquefied carbon dioxide mode;

[0012] Mode 2, carbon capture to produce liquefied carbon dioxide coupled with the zero-power supply mode without shutting down the machine;

[0013] Mode 3, carbon capture to produce liquefied carbon dioxide coupled with the peak power generation mode.

[0014] Optionally, in Mode 1, the flue gas from the boiler exhaust enters the CCUS carbon dioxide reduction device to absorb heat and release carbon dioxide. After heat exchange with the steam turbine condensate through the third heat exchanger, it flows into the compressor for pressurization, and after cooling and liquefaction through the fourth heat exchanger, it is stored in the high-pressure storage tank and can be transported out through pipelines as liquefied carbon dioxide products.

[0015] Optionally, in Mode 2, the compressor speed is increased, the compressor power consumption is increased, and all the output of the coal-fired power unit after deducting the plant electricity consumption is consumed to achieve zero-power supply operation of the coal-fired power unit without shutting down the machine, and the adsorption tower enters the energy storage mode.

[0016] Optionally, in Mode 2, on the basis of Mode 1, the fifth heat exchanger receives heat from the boiler high-temperature flue gas or the steam turbine high-temperature steam and transports it to the adsorption tower to heat the adsorption tower, so that the carbon dioxide therein is desorbed and released, and together with the carbon dioxide from the CCUS carbon dioxide reduction device, it is fed into the compressor for pressurization, cooled and liquefied, and stored in the high-pressure liquefied storage tank.

[0017] Optionally, in Mode 3, on the basis of Mode 1, part of the high-pressure carbon dioxide in the high-pressure liquefied storage tank flows into the turbine through the sixth heat exchanger to absorb heat and expand to do work and generate electricity. The low-pressure carbon dioxide after doing work returns to the cooled adsorption tower for adsorption and storage for the next energy storage use.

[0018] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0019] The system and method for coupling coal-fired power CCUS carbon capture with adsorption-type carbon dioxide energy storage provided by the present invention can significantly improve the deep peak shaving, peak load output, and rapid load change capabilities of the unit on the basis of the original CCUS carbon capture system for the future advanced coal-fired power unit's deep peak shaving, start-stop peak shaving, rapid load change, peak load output, and high-efficiency carbon emission reduction requirements. When the unit participates in start-stop peak shaving, it can operate without shutdown and zero power supply. Each module is deeply coupled, and the energy is effectively utilized in a cascaded manner, which can bring considerable economic and social benefits to the power plant. The low-pressure adsorption technology is used to store low-pressure carbon dioxide instead of the conventional gas storage tank, which greatly reduces the floor area and investment cost, and realizes the market application of large-scale energy storage matching high-power coal-fired power units. Brief Description of the Drawings

[0020] The present invention will be described by way of examples with reference to the accompanying drawings, where:

[0021] Figure 1 is a schematic structural diagram of the system for coupling coal-fired power CCUS carbon capture with adsorption-type carbon dioxide energy storage.

[0022] Reference numerals in the figure: 1 - first heat exchanger, 2 - second heat exchanger, 3 - adsorption tower, 4 - third heat exchanger, 5 - CCUS carbon dioxide reduction device, 6 - compressor, 7 - turbine, 8 - fourth heat exchanger, 9 - high-pressure liquefied storage tank, 10 - fifth heat exchanger, 11 - sixth heat exchanger. Detailed Embodiments

[0023] The present invention will be described in detail below with reference to the accompanying drawings.

[0024] All features disclosed in this specification, or all steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

[0025] Any feature disclosed in this specification, unless specifically described, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically described, each feature is only an example in a series of equivalent or similar features.

[0026] The system for coupling coal-fired power CCUS carbon capture with adsorption-type carbon dioxide energy storage, as Figure 1As shown in the figure, it includes a CCUS carbon dioxide reduction device 5, a third heat exchanger 4, a compressor 6, a fourth heat exchanger 8, and a high-pressure liquefied storage tank 9 connected in sequence along the flow direction. The input end of the CCUS carbon dioxide reduction device 5 is connected to the boiler flue gas line; the output end of the high-pressure liquefied storage tank 9 is connected to the liquefied carbon dioxide output line; a carbon dioxide low-pressure adsorption long-term energy storage system is connected in parallel with the compressor 6, the fourth heat exchanger 8, and the high-pressure liquefied storage tank 9. The carbon dioxide low-pressure adsorption long-term energy storage system flows from the downstream of the high-pressure liquefied storage tank 9 to the upstream of the compressor 6; a valve is provided downstream of the high-pressure liquefied storage tank 9 to respectively adjust the flow rates to the liquefied carbon dioxide output line and the carbon dioxide low-pressure adsorption long-term energy storage system.

[0027] Specifically, the CCUS reduction device in the system uses the heat of compressed high-temperature carbon dioxide to separate carbon dioxide from the flue gas and send it to the compressor 6 for pressurized storage. The carbon dioxide low-pressure adsorption long-term energy storage system uses low-pressure adsorption technology to store the low-pressure and low-temperature carbon dioxide after the turbine 7 does work, greatly reducing the floor area and investment cost, and realizing the market application of large-scale energy storage for matching high-power coal-fired power units. The compressor 6 in the system is a common compressor 6 for CCUS and the carbon dioxide energy storage system, receiving carbon dioxide from the carbon dioxide low-pressure adsorption long-term energy storage system and the CCUS reduction device. The compressor 6 supports variable-speed operation to match different operation mode requirements; the outlet of the compressor 6 is connected to the fourth heat exchanger 8. The high-pressure liquefied storage tank 9 in the system receives and stores the pressurized and cooled carbon dioxide, is provided with interfaces for transporting to the carbon dioxide low-pressure adsorption long-term energy storage system and outside the system, and is provided with valves to dynamically adjust the flow rates of the two outlets.

[0028] The system mainly has three operating modes: 1) Carbon capture to produce liquid carbon dioxide. The CCUS part in the system captures and cools carbon dioxide to liquefy it, and the liquid carbon dioxide is stored in the high-pressure liquefied storage tank 9. This part is in a long-term operating state. 2) Carbon capture to produce liquid carbon dioxide + zero power supply operation: When the unit needs to stop due to participating in start-stop peak regulation, by increasing the speed of the compressor 6 and the compression power, after the coal-fired power unit drops to the minimum load, all the output except the auxiliary power consumption is used to drive the compressor 6, realizing zero power supply operation of the coal-fired power unit without stopping, avoiding a large amount of energy loss caused by the coal-fired power unit participating in start-stop peak regulation. When the coal-fired power unit only needs to operate at a low load without stopping, the minimum power supply load of the coal-fired power unit can also be further reduced by increasing the power consumption of the compressor 6, improving the deep peak regulation ability of the coal-fired power unit. The heat of the pressurized high-temperature carbon dioxide returns to the carbon dioxide reduction module of CCUS through the heat exchanger for carbon dioxide reduction. After being cooled by the heat exchanger, it is stored in the storage tank and can be used for subsequent energy release processes or external transportation. 3) Carbon capture to produce liquid carbon dioxide + peak operation: When the coal-fired power unit needs to increase power generation, the energy release part of the system is put into operation. A stream of high-temperature flue gas / steam is introduced to heat the high-pressure carbon dioxide and then enters the turbine 7 to expand and do work to drive the generator to generate electricity, effectively improving the peak output capacity of the coal-fired power unit. According to the ramp rate requirement of the power plant, the turbine 7 can be in a stopped or hot standby state when it is not generating electricity. The expanded low-pressure carbon dioxide then returns to the adsorption tower 3 that has been cooled by the first heat exchanger and the second heat exchanger for adsorption and storage, waiting to be used in the next energy storage stage.

[0029] In addition, if the power plant has the condition to use low-cost wind power and photovoltaic power that cannot be connected to the grid as the power consumption of the compressor 6, the revenue can be further increased. The power consumption of the compressor 6 is low-cost wind power and photovoltaic power that cannot be connected to the grid, and the coal consumption of the coal-fired power unit decreases under the same power generation load. When peak output needs to be increased, the energy release system operates, and the turbine 7 generates electricity and is connected to the grid, converting low-cost wind power and photovoltaic power that cannot be connected to the grid into high-quality electricity for grid connection, which can bring higher economic and social benefits to the power plant.

[0030] As another specific embodiment, the low-pressure carbon dioxide adsorption long-duration energy storage system includes a sixth heat exchanger 11, a turbine 7, and an adsorption tower 3 connected in sequence along the flow direction; the adsorption tower 3 is also bidirectionally connected to a fifth heat exchanger 10 and a first heat exchanger 1. The system is composed of a carbon dioxide adsorption tower 3, multiple heat exchangers, a turbine 7, valves, and pipelines added on the basis of the original CCUS system. In the energy storage stage, the adsorption tower 3 in the system absorbs the heat of high-temperature flue gas / steam to desorb the carbon dioxide stored therein and sends it to the compressor 6 for pressurization; in the energy release stage, the adsorption tower 3 receives the low-pressure and low-temperature carbon dioxide after doing work through the turbine 7 and adsorbs and stores it. The turbine 7 in the system is connected to a generator to receive high-pressure and high-temperature carbon dioxide for expansion power generation, and the expanded low-pressure carbon dioxide returns to the adsorption tower 3 cooled by the first heat exchanger and the second heat exchanger for re-adsorption and storage. Among them, the compressor 6 and the turbine 7 in the system can be designed as staged compression / intermediate cooling and staged expansion / intermediate heat absorption according to specific parameter requirements.

[0031] As another specific embodiment, the first heat exchanger 1 is bidirectionally connected to the second heat exchanger 2. By setting an additional heat exchange step, more refined energy management can be achieved, the cascade effective utilization of energy in each link can be realized, the waste heat or low-temperature energy in the system can be fully utilized, and the system efficiency can be effectively improved.

[0032] As another specific embodiment, the fourth heat exchanger 8 and the CCUS carbon dioxide reduction device 5 are bidirectionally connected; the third heat exchanger 4 and the second heat exchanger 2 are bidirectionally connected to the steam turbine condensate line; the fifth heat exchanger 10 and the sixth heat exchanger 11 are bidirectionally connected to the boiler high-temperature flue gas line or the steam turbine high-temperature steam line; the first heat exchanger 1 is bidirectionally connected to the steam turbine feed water line. By connecting the condensate line of the steam turbine, it can be used to preheat the carbon dioxide gas entering the system or cool the gas leaving the system. At the same time, during the process of preheating the condensate, the heat discharged by the steam turbine can be recovered, reducing heat energy waste. By being connected to the high-temperature flue gas or steam line, the heat energy discharged by the boiler or steam turbine can be efficiently recovered and used to heat or reduce carbon dioxide, improving the thermal efficiency of the entire system. By connecting the feed water line of the steam turbine, it can be used to preheat the feed water, thereby reducing the energy required for the steam turbine to heat the feed water and improving the thermal efficiency of the entire system. Since the heat generated during the carbon dioxide energy storage process in the system is absorbed and utilized respectively through the steam turbine feed water, condensate, and the reduction process of CCUS, and the heat absorption required for the energy storage / release process is provided by the boiler flue gas or steam turbine steam, the energy utilization efficiency is effectively improved; at the same time, compared with the conventional carbon dioxide energy storage system, the system heat does not require energy storage / release self-balancing, and the system control is simpler and more reliable.

[0033] As another specific embodiment, the fifth heat exchanger 10 and the sixth heat exchanger 11 are bidirectionally connected to the same high-temperature flue gas line of the boiler or the high-temperature steam line of the steam turbine. Allowing the two heat exchangers to use the same heat source under different process stages or conditions improves the utilization rate and flexibility of thermal energy, reduces the consumption of external energy, and lowers the overall operating cost.

[0034] A method for coal-fired power CCUS carbon capture coupled with adsorption-type carbon dioxide energy storage includes the following switchable modes:

[0035] Mode 1, carbon capture to produce liquefied carbon dioxide mode;

[0036] Mode 2, carbon capture to produce liquefied carbon dioxide coupled with the zero-power supply mode without shutting down;

[0037] Mode 3, carbon capture to produce liquefied carbon dioxide coupled with peak power generation mode.

[0038] This solution can greatly improve the unit's deep peak shaving, peak output, and rapid load-changing capabilities on the original CCUS carbon capture system. When the unit participates in start-stop peak shaving, it can operate with zero power supply without shutting down. Each module is deeply coupled, and the energy is effectively utilized in a cascaded manner, bringing considerable economic and social benefits to the power plant.

[0039] As another specific embodiment, in Mode 1, the flue gas from the boiler exhaust enters the CCUS carbon dioxide reduction device 5 to absorb heat and release carbon dioxide. After exchanging heat with the condensate of the steam turbine through the third heat exchanger 4, it flows into the compressor 6 for pressurization. After being cooled and liquefied by the fourth heat exchanger 8, it is stored in the high-pressure liquefied storage tank 9 and can be transported outwards through pipelines as liquefied carbon dioxide products. In this way, only the CCUS carbon dioxide reduction device 5, the third heat exchanger 4, the compressor 6, the fourth heat exchanger 8, and the high-pressure liquefied storage tank 9 of this device are working, without consuming additional electricity or generating additional electricity.

[0040] As another specific embodiment, in Mode 2, the rotational speed of the compressor 6 is increased, the power consumption of the compressor 6 is increased, and all the output of the coal-fired power unit after deducting the auxiliary power consumption is consumed, realizing the zero-power supply operation of the coal-fired power unit without shutting down, and the adsorption tower 3 enters the energy storage mode.

[0041] As another specific embodiment, in Mode 2, based on Mode 1, the fifth heat exchanger 10 receives heat from the high-temperature flue gas of the boiler or the high-temperature steam of the steam turbine and transports it to the adsorption tower 3 to heat the adsorption tower 3, so that the carbon dioxide therein is desorbed and released, and is combined with the carbon dioxide from the CCUS carbon dioxide reduction device 5 and then flows into the compressor 6 for pressurization. After cooling and liquefaction, it is stored in the high-pressure liquefied storage tank 9. In this way, the compressor 6 compresses the carbon dioxide in the adsorption tower 3, which is an additional power consumption. The resulting product is stored in the high-pressure liquefied storage tank 9 and does not pass through the turbine 7, so no additional electricity is generated. Moreover, the high-pressure carbon dioxide in the high-pressure liquefied storage tank 9 provides a reserve for additional power generation.

[0042] As another specific embodiment, in Mode 3, based on Mode 1, part of the high-pressure carbon dioxide in the high-pressure liquefied storage tank 9 absorbs heat through the sixth heat exchanger 11 and then flows into the turbine 7 to expand and do work for power generation. The low-pressure carbon dioxide after doing work returns to the adsorption tower 3 that has been cooled by the first heat exchanger 1 and the second heat exchanger 2 for adsorption and storage, waiting for the next energy storage use. In this way, the high-pressure carbon dioxide in the high-pressure liquefied storage tank 9 generates additional electricity through the turbine 7, and cooperates with the original generator set of the original coal-fired power unit to achieve peak power generation. The resulting product is stored in the adsorption tower 3 and does not pass through the compressor 6, so no additional power consumption is incurred. Moreover, the low-pressure carbon dioxide in the adsorption tower 3 provides a reserve for additional power consumption.

[0043] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, as well as any new method or process step or any new combination disclosed.

Claims

1. A coal-fired power generation CCUS carbon capture coupled adsorption carbon dioxide energy storage system, characterized by: It includes a CCUS carbon dioxide reduction device, a third heat exchanger, a compressor, a fourth heat exchanger and a high-pressure liquefied storage tank which are sequentially connected in the flow direction, wherein the input end of the CCUS carbon dioxide reduction device is connected to the boiler exhaust flue gas line; the output end of the high-pressure liquefied storage tank is connected to the liquefied carbon dioxide output line; the compressor, the fourth heat exchanger and the high-pressure liquefied storage tank are connected in parallel with a carbon dioxide low-pressure adsorption long-term energy storage system, which flows from the downstream of the high-pressure liquefied storage tank to the upstream of the compressor; a valve is provided downstream of the high-pressure liquefied storage tank to adjust the flow to the liquefied carbon dioxide output line and the carbon dioxide low-pressure adsorption long-term energy storage system respectively; the carbon dioxide low-pressure adsorption long-term energy storage system includes a sixth heat exchanger, a turbine and an adsorption tower which are sequentially connected in the flow direction; the adsorption tower is also bidirectionally connected to a fifth heat exchanger and a first heat exchanger.

2. The system of coal-fired power generation CCUS carbon capture coupled adsorption carbon dioxide energy storage according to claim 1, characterized in that: The first heat exchanger is bidirectionally connected to the second heat exchanger.

3. The coal-fired power generation CCUS carbon capture coupled adsorption carbon dioxide energy storage system according to claim 2, characterized in that: The fourth heat exchanger and the CCUS carbon dioxide reduction device are bidirectionally connected; the third heat exchanger and the second heat exchanger are bidirectionally connected to the turbine condensate line; the fifth heat exchanger and the sixth heat exchanger are bidirectionally connected to the boiler high-temperature flue gas line or the turbine high-temperature steam line; the first heat exchanger is bidirectionally connected to the turbine feed water line.

4. The coal-fired power generation CCUS carbon capture coupled adsorption carbon dioxide energy storage system according to claim 3, characterized in that: The fifth heat exchanger and the sixth heat exchanger are bidirectionally connected to the same boiler high-temperature flue gas line or turbine high-temperature steam line.

5. A method for carbon capture and coupled adsorption carbon dioxide energy storage in coal-fired power generation CCUS, the method being based on the system for carbon capture and coupled adsorption carbon dioxide energy storage in coal-fired power generation CCUS according to any one of claims 1 to 4, characterized in that: Includes the following modes that can be switched: Mode 1: Carbon capture to produce liquefied carbon dioxide mode; Mode 2: Carbon capture to produce liquefied carbon dioxide coupled with non-stop zero power supply mode; Mode 3: Carbon capture to produce liquefied carbon dioxide coupled with peak power generation mode.

6. The method for carbon capture coupled adsorption carbon dioxide energy storage by coal-fired power generation CCUS as claimed in claim 5, characterized in that: In mode 1, the flue gas from the boiler exhaust enters the CCUS carbon dioxide reduction device, absorbs heat and is reduced to release carbon dioxide, which then exchanges heat with the turbine condensate through the third heat exchanger and flows into the compressor for pressurization. After being cooled and liquefied through the fourth heat exchanger, it is stored in a high-pressure liquefied storage tank and can be transported to the outside as a liquefied carbon dioxide product through a pipeline.

7. The method for carbon capture coupled adsorption carbon dioxide energy storage by coal-fired power generation CCUS as claimed in claim 5, characterized in that: In mode 2, the compressor speed is increased, the compressor power consumption is increased, and all the output of the coal-fired power unit after deducting the factory power consumption is consumed, so that the coal-fired power unit can operate without stopping and zero power supply, and the adsorption tower enters the energy storage mode.

8. The method for carbon capture coupled adsorption carbon dioxide energy storage by coal-fired power generation CCUS as claimed in claim 7, characterized in that: In mode 2, based on mode 1, the heat from the high-temperature flue gas of the boiler or the high-temperature steam of the turbine is received through the fifth heat exchanger and transmitted to the adsorption tower to heat the adsorption tower, so that the carbon dioxide therein is desorbed and released, and then combined with the carbon dioxide from the CCUS carbon dioxide reduction device, it is pressurized by the compressor, cooled, liquefied and stored in a high-pressure liquefied storage tank.

9. The method for carbon capture coupled adsorption carbon dioxide energy storage by coal-fired power generation CCUS as claimed in claim 5, characterized in that: In mode 3, based on mode 1, part of the high-pressure carbon dioxide in the high-pressure liquefied storage tank absorbs heat through the sixth heat exchanger and then flows into the turbine to expand and generate electricity. The low-pressure carbon dioxide that has completed the work returns to the adsorption tower after being cooled by the first and second heat exchangers for adsorption and storage, waiting for the next energy storage use.

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