Coal power CCUS carbon capture coupling adsorption type carbon dioxide energy storage system and method

Abstract

The invention discloses a coal power CCUS carbon capture coupling adsorption type carbon dioxide energy storage system and method. The system comprises a CCUS carbon dioxide reduction device, a third heat exchanger, a compressor, a fourth heat exchanger and a high-pressure liquefaction storage tank which are sequentially connected in the flowing direction, and the input end of the CCUS carbon dioxide reduction device communicates with a boiler smoke exhaust line; the output end of the high-pressure liquefaction storage tank is communicated with a liquefied carbon dioxide output line; the compressor, the fourth heat exchanger and the high-pressure liquefaction storage tank are jointly connected with a carbon dioxide low-pressure adsorption type long-time energy storage system in parallel, and the carbon dioxide low-pressure adsorption type long-time energy storage system flows to the upstream of the compressor from the downstream of the high-pressure liquefaction storage tank. And a valve is arranged at the downstream of the high-pressure liquefaction storage tank. The peak output, the deep peak regulation capability and the rapid load change capability of the coal power unit can be improved, non-stop zero-power-supply operation of the coal power unit is realized, and considerable economic and social benefits are brought to a power plant.

Description

Technical Field

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

[0002] In the context of "dual carbon", with the increase in the generation of intermittent and unstable renewable energy such as wind power and solar power, and the high level of wind and solar power abandonment, the power grid has higher and higher requirements for the peak output and deep peak-shaving capabilities of coal-fired power units. At present, coal-fired power units cannot achieve long-term deep peak-shaving or zero power supply operation without stopping. Due to the maximum evaporation capacity of the boiler, the peak capacity in summer is also relatively limited; at the same time, the efficiency improvement of the unit cannot achieve a significant reduction in carbon emissions, and the CCUS carbon capture system is still one of the main means. Summary of the invention

[0003] The purpose of the present invention is to provide a system and method for coal-fired power CCUS carbon capture coupled adsorption carbon dioxide energy storage in response to the above-mentioned problems, which 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.

[0004] The technical solution adopted by the present invention is as follows: A system of coal-fired power CCUS carbon capture coupled adsorption-type carbon dioxide energy storage, comprising 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, 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-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 to the liquefied carbon dioxide output line and the carbon dioxide low-pressure adsorption-type long-term energy storage system.

[0005] Optionally, the carbon dioxide low-pressure adsorption 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 to the fifth heat exchanger and the first heat exchanger.

[0006] Optionally, the first heat exchanger is bidirectionally connected to a second heat exchanger.

[0007] Optionally, 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; and the first heat exchanger is bidirectionally connected to the turbine feed water line.

[0008] Optionally, the fifth heat exchanger and the sixth heat exchanger are bidirectionally connected to the same boiler high-temperature flue gas circuit or turbine high-temperature steam circuit.

[0009] The method of coupling coal-fired power generation CCUS carbon capture with adsorption carbon dioxide energy storage includes the following switchable modes: 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.

[0010] Alternatively, in Mode 1, the flue gas from the boiler exhaust enters the CCUS carbon dioxide reduction device for heat absorption and reduction to release carbon dioxide, which then exchanges heat with the turbine condensate through the third heat exchanger and flows into the compressor for pressurization. It is then cooled and liquefied through the fourth heat exchanger and stored in a high-pressure storage tank. The liquefied carbon dioxide product can be transported outward through a pipeline.

[0011] Alternatively, 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.

[0012] Alternatively, in Mode 2, based on Mode 1, 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 transported 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.

[0013] Alternatively, 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 cooled adsorption tower for adsorption and storage, awaiting the next energy storage use.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: The system and method of coal-fired power CCUS carbon capture coupled adsorption carbon dioxide energy storage provided by the present invention can greatly improve the deep peak regulation, peak output and rapid load change capabilities of the units on the original CCUS carbon capture system for the deep peak regulation, start-stop peak regulation, rapid load change, peak output and efficient carbon emission reduction needs of future advanced coal-fired power units. The units can operate without stopping and with zero power supply when participating in start-stop peak regulation. The deep coupling of each module and the effective utilization of energy ladder can bring considerable economic and social benefits to the power plant. The use of low-pressure adsorption technology to store low-pressure carbon dioxide instead of conventional gas storage can greatly reduce the floor space and investment cost, and realize the market application of large-scale energy storage matching large-power coal-fired power units. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 It is a structural schematic diagram of the coal-fired power CCUS carbon capture coupled adsorption carbon dioxide energy storage system.

[0016] Markings 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 DESCRIPTION

[0017] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0018] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0019] Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0020] Coal-fired power CCUS carbon capture coupled adsorption carbon dioxide energy storage system, such as Figure 1As shown, 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 which are connected in sequence along the flow direction, the input end of the CCUS carbon dioxide reduction device 5 is connected to the boiler exhaust flue gas line; the output end of the high-pressure liquefied storage tank 9 is connected to the liquefied carbon dioxide output line; the compressor 6, the fourth heat exchanger 8 and the high-pressure liquefied storage tank 9 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 9 to the upstream of the compressor 6; a valve is provided downstream of the high-pressure liquefied storage tank 9 to adjust the flow to the liquefied carbon dioxide output line and the carbon dioxide low-pressure adsorption long-term energy storage system respectively.

[0021] Specifically, the CCUS reduction device in the system uses the heat of the high-temperature carbon dioxide after compression to separate the carbon dioxide from the flue gas and send it to the compressor 6 for pressurized storage. The low-pressure adsorption long-term energy storage system of carbon dioxide uses low-pressure adsorption technology to store low-pressure and low-temperature carbon dioxide after the turbine 7 does work, which greatly reduces the floor space and investment costs, and realizes the market application of large-scale energy storage matching large-power coal-fired power units. The compressor 6 in the system is a shared compressor 6 for CCUS and carbon dioxide energy storage system, which receives carbon dioxide from the low-pressure adsorption long-term energy storage system of carbon dioxide and the CCUS reduction device. The compressor 6 supports variable speed operation to match the requirements of different operating modes; the outlet of compressor 6 is connected to the fourth heat exchanger 8. The high-pressure liquefied storage tank 9 in the system receives and stores pressurized and cooled carbon dioxide, and is provided with an interface for transmission to the low-pressure adsorption long-term energy storage system of carbon dioxide and outside the system, and is provided with a valve to dynamically adjust the flow of the two output ports.

[0022] The system has three main operating modes: 1) Carbon capture to produce liquid carbon dioxide, the CCUS part of the system captures carbon and cools and liquefies to prepare liquid carbon dioxide and stores it in the high-pressure liquefied storage tank 9, which is in a long-term operation state. 2) Carbon capture to produce liquid carbon dioxide + zero power supply operation: When the unit needs to shut down due to participation in start-stop peak regulation, by increasing the speed of compressor 6 and increasing the compression power, the coal-fired power unit is reduced to the minimum load, and the remaining output is all used to drive compressor 6 after deducting the plant power, so as to achieve zero power supply operation of the coal-fired power unit without stopping, avoiding a large amount of energy loss caused by the participation of the coal-fired power unit in the start-stop peak regulation. When the coal-fired power unit does not need to shut down and only needs to operate at low load, the minimum power supply load of the coal-fired power unit can also be further reduced by increasing the power consumption of compressor 6, thereby improving the deep peak regulation capacity 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, and is stored in the storage tank after cooling by the heat exchanger for subsequent energy release process or external transmission. 3) Carbon capture to produce liquid carbon dioxide + peak operation: When the coal-fired power unit needs to increase its power generation, the energy release part of the system is put into operation, and a stream of high-temperature flue gas / steam is introduced to heat the high-pressure carbon dioxide, which then enters turbine 7 to expand and drive the generator to generate electricity, thereby effectively improving the peak output capacity of the coal-fired power unit. According to the power plant's ramp rate requirements, turbine 7 can be shut down or in hot standby mode when it is not generating electricity. The expanded low-pressure carbon dioxide returns to the adsorption tower 3 after being cooled by the first heat exchanger and the second heat exchanger for adsorption and storage, awaiting use in the next energy storage stage.

[0023] In addition, if the power plant has the conditions to use low-priced wind power and photovoltaic power that cannot be connected to the grid as the power consumption of compressor 6, the profit can be further increased. The power consumption of compressor 6 is low-priced wind power and photovoltaic power that cannot be connected to the grid, and the coal consumption of coal-fired power units is reduced under the same power generation load; when it is necessary to increase the peak output, the energy release system is operated, and turbine 7 generates electricity and connects to the grid, converting the low-priced wind power and photovoltaic power that cannot be connected to the grid into high-quality electricity for the grid, which can bring higher economic and social benefits to the power plant.

[0024] As another specific implementation, the carbon dioxide low-pressure adsorption long-term 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 the fifth heat exchanger 10 and the 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 to the original CCUS system. The adsorption tower 3 in the system absorbs the heat of high-temperature flue gas / steam to desorb the carbon dioxide stored therein during the energy storage stage 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 the turbine 7 does work, 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 and power generation. The expanded low-pressure carbon dioxide returns to the adsorption tower 3 after being cooled by the first and second heat exchangers for adsorption and storage again. Among them, the compressor 6 and turbine 7 in the system can be designed as segmented compression / intermediate cooling and segmented expansion / intermediate heat absorption according to specific parameter requirements.

[0025] As another specific implementation, the first heat exchanger 1 is bidirectionally connected to the second heat exchanger 2. Setting an additional heat exchange step can achieve more sophisticated energy management, effectively utilize the energy of each link, make full use of waste heat or low-temperature energy in the system, and effectively improve system efficiency.

[0026] As another specific implementation, 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 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 turbine high-temperature steam line; the first heat exchanger 1 is bidirectionally connected to the 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, in the process of preheating the condensate, the heat discharged by the steam turbine can be recovered to reduce the waste of heat energy. By connecting with the high-temperature flue gas or steam line, the heat energy discharged by the boiler or steam turbine can be efficiently recovered for heating or reducing carbon dioxide, thereby 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 by the carbon dioxide energy storage process in the system is absorbed and utilized through the turbine feed water, condensate and CCUS reduction process, and the heat required for the storage / release process is provided by the boiler flue gas or turbine steam, the energy utilization efficiency is effectively improved; at the same time, compared with conventional carbon dioxide energy storage systems, the system heat does not require self-balancing of storage / release, and the system control is simpler and more reliable.

[0027] As another specific implementation, the fifth heat exchanger 10 and the sixth heat exchanger 11 are bidirectionally connected to the same boiler high-temperature flue gas line or turbine high-temperature steam line, allowing the two heat exchangers to use the same heat source in different process stages or conditions, thereby improving the utilization rate and flexibility of thermal energy, reducing the consumption of external energy, and reducing the overall operating cost.

[0028] The method of coupling coal-fired power generation CCUS carbon capture with adsorption carbon dioxide energy storage includes the following switchable modes: 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.

[0029] This solution can greatly improve the unit's deep peak regulation, peak output and rapid load change capabilities on the basis of the original CCUS carbon capture system. The unit can operate without stopping and with zero power supply when participating in start-stop peak regulation. The modules are deeply coupled and the energy cascade is effectively utilized, which can bring considerable economic and social benefits to the power plant.

[0030] As another specific implementation, in mode 1, the flue gas from the boiler exhaust enters the CCUS carbon dioxide reduction device 5 to absorb heat and reduce the released carbon dioxide, which then exchanges heat with the turbine condensate through the third heat exchanger 4 and flows into the compressor 6 for pressurization, and is cooled and liquefied through the fourth heat exchanger 8 and stored in the high-pressure liquefied storage tank 9, and the liquefied carbon dioxide product can be transported outward through a pipeline. In this mode, 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 are working in this device, and no additional electricity is consumed or generated.

[0031] As another specific implementation method, in mode 2, the rotation speed of compressor 6 is increased, the power consumption of compressor 6 is increased, and all the output of the coal-fired power unit after deducting the factory power is consumed, so that the coal-fired power unit can operate without stopping and zero power supply, and the adsorption tower 3 enters the energy storage mode.

[0032] As another specific implementation, 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 10 and transmitted 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 into the compressor 6 for pressurization, cooled and liquefied and stored in the high-pressure liquefied storage tank 9. In this way, the compressor 6 compresses the carbon dioxide in the adsorption tower 3 as additional power consumption, and the resulting product is stored in the high-pressure liquefied storage tank 9 without passing through the turbine 7, so no additional power is generated, and the high-pressure carbon dioxide in the high-pressure liquefied storage tank 9 provides a reserve for additional power generation.

[0033] As another specific implementation, 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 flows into the turbine 7 to expand and generate electricity. The low-pressure carbon dioxide that has completed the work returns to the adsorption tower 3 after being 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 is passed through the turbine 7 to generate additional electricity, and the original generator set of the original coal-fired power unit is used to achieve peak power generation. The resulting product is stored in the adsorption tower 3, does not pass through the compressor 6, and thus does not consume additional electricity. In addition, the low-pressure carbon dioxide in the adsorption tower 3 provides a reserve for additional electricity consumption.

[0034] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps 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 connected in sequence along 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, 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 to respectively adjust the flow to the liquefied carbon dioxide output line and the carbon dioxide low-pressure adsorption long-term energy storage system.

2. The coal-fired power generation CCUS carbon capture coupled adsorption carbon dioxide energy storage system according to claim 1, characterized in that: The carbon dioxide low-pressure adsorption long-term energy storage system comprises a sixth heat exchanger, a turbine and an adsorption tower which are sequentially connected along the flow direction; the adsorption tower is also bidirectionally connected to the fifth heat exchanger and the first 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 first heat exchanger is bidirectionally connected to the second heat exchanger.

4. The system of coal-fired power generation CCUS carbon capture coupled adsorption carbon dioxide energy storage according to claim 3, 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.

5. The system of coal-fired power generation CCUS carbon capture coupled adsorption carbon dioxide energy storage according to claim 4, 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.

6. A method for coupling carbon capture and adsorption carbon dioxide energy storage in coal-fired power generation CCUS, including 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.

7. The method for carbon capture coupled adsorption carbon dioxide energy storage by coal-fired power generation CCUS as claimed in claim 6, characterized in that: In mode 1, the flue gas from the boiler exhaust enters the CCUS carbon dioxide reduction device to absorb heat and reduce the released 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.

8. The method for carbon capture coupled adsorption carbon dioxide energy storage by coal-fired power generation CCUS as claimed in claim 6, 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.

9. The method for carbon capture coupled adsorption carbon dioxide energy storage by coal-fired power generation CCUS as claimed in claim 8, 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.

10. The method for carbon capture coupled adsorption carbon dioxide energy storage by coal-fired power generation CCUS according to claim 6, 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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