Coal-electricity CCUS methanol preparation coupling adsorption type carbon dioxide energy storage system and method

Abstract

The invention discloses a coal power CCUS methanol preparation 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 and a methanol preparation device 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 input end of the methanol preparation device is communicated with the compressor and a hydrogen input line, and the output end of the methanol preparation device is communicated with a methanol output line; the compressor is connected with a carbon dioxide low-pressure adsorption type long-time energy storage system in parallel, the carbon dioxide low-pressure adsorption type long-time energy storage system flows to the upstream of the compressor from the downstream of the compressor, and a valve is arranged on the downstream of the compressor. According to the method, the peak output, the deep peak regulation capacity and the rapid load change capacity of the coal power unit can be improved, non-stop zero-power-supply operation of the coal power unit is realized, green resource utilization of carbon dioxide is realized by preparing methanol through carbon capture, 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, in particular to a system and method for coupling coal-fired power generation CCUS with methanol production to adsorption-type carbon dioxide energy storage. Background Art

[0002] With the increase in the amount of renewable energy such as wind power and solar power, which are intermittent and unstable, 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 to produce methanol coupled with adsorption-type carbon dioxide energy storage in response to the above-mentioned problems, which can improve the peak output, deep peak-shaving capability and rapid load-changing capability of coal-fired power units, realize non-stop zero-power operation of coal-fired power units, and realize green resource utilization of carbon dioxide by producing methanol through carbon capture, thereby bringing considerable economic and social benefits to power plants.

[0004] The technical solution adopted by the present invention is as follows: A system for producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage, comprising a CCUS carbon dioxide reduction device, a third heat exchanger, a compressor and a methanol production device 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 input end of the methanol production device is connected to the compressor and the hydrogen input line, and the output end of the methanol production device is connected to the methanol output line; the compressor is connected in parallel with a carbon dioxide low-pressure adsorption long-term energy storage system, the carbon dioxide low-pressure adsorption long-term energy storage system flows from the downstream of the compressor to the upstream of the compressor, and a valve is provided downstream of the compressor to respectively adjust the flow to the methanol production device and the carbon dioxide low-pressure adsorption long-term energy storage system.

[0005] Optionally, the carbon dioxide low-pressure adsorption long-term energy storage system includes a fourth heat exchanger, a high-pressure liquefied storage tank, a seventh heat exchanger, a turbine and an adsorption tower connected in sequence along the flow direction; the adsorption tower is also bidirectionally connected to the sixth heat exchanger and the first heat exchanger.

[0006] Optionally, a fifth heat exchanger is provided between the fourth heat exchanger and the high-pressure liquefied storage tank; and the first heat exchanger is bidirectionally connected to the second heat exchanger.

[0007] Optionally, the third heat exchanger, the fifth heat exchanger and the second heat exchanger are bidirectionally connected to the turbine condensate line; the CCUS carbon dioxide reduction device, the sixth heat exchanger and the seventh heat exchanger are bidirectionally connected to the boiler high-temperature flue gas line or the turbine high-temperature steam line; the first heat exchanger and the fourth heat exchanger are bidirectionally connected to the turbine feed water line.

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

[0009] The method of producing methanol from coal-fired power CCUS coupled with adsorption carbon dioxide energy storage includes the following switchable modes: Mode 1: Carbon capture to methanol mode; Mode 2: Carbon capture to methanol coupled with non-stop zero power supply mode; Mode 3: Carbon capture to produce methanol coupled with peak power generation mode.

[0010] Alternatively, in Mode 1, the flue gas from the boiler exhaust enters the CCUS carbon dioxide reduction unit to absorb heat and reduce to release carbon dioxide, then passes through the third heat exchanger and the turbine condensate to flow into the compressor for pressurization, and then passes into the methanol production unit together with green hydrogen to prepare methanol.

[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 sixth heat exchanger and transported to the adsorption tower to heat the adsorption tower, so that the carbon dioxide therein is desorbed and released, and is then fed into the compressor for pressurization together with the carbon dioxide from the CCUS carbon dioxide reduction device. Part of the pressurized carbon dioxide is reacted with green hydrogen to prepare methanol, and the other part is cooled and liquefied through the fourth heat exchanger and the fifth heat exchanger in turn, and then stored in a high-pressure liquefied storage tank to be used in the energy release stage.

[0013] Alternatively, in Mode 3, based on Mode 1, the high-pressure carbon dioxide in the high-pressure liquefied storage tank absorbs heat through the seventh 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 heat exchanger and the second heat exchanger 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 for the coal-fired CCUS methanol production coupled with adsorption-type carbon dioxide energy storage provided by the present invention can greatly improve the deep peak regulation, peak output and rapid load variation capabilities of the units on the original CCUS carbon capture system for the deep peak regulation, start-stop peak regulation, rapid load variation, peak output and efficient carbon emission reduction requirements of future advanced coal-fired power units. The units can operate without stopping and with zero power supply when participating in the start-stop peak regulation. The high-temperature carbon dioxide and green hydrogen after capture and compression can also be used to produce methanol to replace the traditional carbon dioxide cooling and liquefaction storage, realizing the green resource utilization of carbon dioxide, which can bring considerable economic and social benefits to power plants. 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 This is a system diagram of coal-fired power CCUS to produce methanol coupled with adsorption-type carbon dioxide energy storage.

[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 unit, 6-compressor, 7-methanol production unit, 8-fourth heat exchanger, 9-fifth heat exchanger, 10-high-pressure liquefied storage tank, 11-sixth heat exchanger, 12-seventh heat exchanger, 13-turbine. 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 methanol production coupled with 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 and a methanol production device 7 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 input end of the methanol production device 7 is connected to the hydrogen input line and the compressor 6, and the output end of the methanol production device 7 is connected to the methanol output line; the compressor 6 is connected in parallel with a carbon dioxide low-pressure adsorption long-term energy storage system, the carbon dioxide low-pressure adsorption long-term energy storage system flows from the downstream of the compressor 6 to the upstream of the compressor 6, and a valve is provided downstream of the compressor 6 to adjust the flow to the methanol production device 7 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 sends it to the compressor 6 for pressurized storage, so as to realize the continuous and stable carbon adsorption, separation and compression of carbon dioxide in the boiler exhaust, and reasonably use the high-temperature carbon dioxide after compression and temperature increase and the green hydrogen prepared by green electricity to prepare methanol, replacing the traditional carbon dioxide cooling and liquefaction storage, and realizing the green resource utilization of carbon dioxide. The carbon dioxide low-pressure adsorption long-term energy storage system uses low-pressure adsorption technology to store low-pressure and low-temperature carbon dioxide after the turbine 13 works, greatly reducing the floor space and investment cost, and realizing the market application of large-scale energy storage matching large-power coal-fired power units. The compressor 6 in the system is a common compressor 6 for CCUS and carbon dioxide energy storage system, which receives carbon dioxide from the low-pressure adsorption long-term energy storage system and CCUS reduction device. The compressor 6 supports variable speed operation to match the requirements of different operation modes, and the output is connected to the low-pressure adsorption long-term energy storage system and the methanol production device 7, and a valve is provided to dynamically adjust the flow of the two output ports.

[0022] The system has three main operating modes: 1) Carbon capture to methanol: When the coal-fired power plant is in normal high load operation and no energy storage / release is required, the system only operates CCUS carbon capture, pressurization and methanol production. 2) Carbon capture to methanol + 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 start-stop of the coal-fired power unit. 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 pressurized high-temperature carbon dioxide is partially cooled by the heat exchanger according to the subsequent energy release demand (power generation power and duration) and stored in the energy storage system for subsequent energy release process, and the remaining high-temperature carbon dioxide is still produced with green hydrogen to produce methanol. 3) Carbon capture to produce methanol + peak operation: When the coal-fired power unit needs to increase its power generation, the energy storage system releases part of the energy into operation, and introduces a stream of high-temperature flue gas / steam to heat the high-pressure carbon dioxide and then enter the turbine 13 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 13 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 for adsorption and storage, pending use in the next energy storage stage. If the power plant has a high demand for the upward ramp rate, a small flow of high-temperature and high-pressure carbon dioxide can be continuously introduced into turbine 13, so that turbine 13 is in hot standby mode, and when the load needs to be increased, it can quickly increase to full load, effectively improving the upward ramp rate of the coal-fired power unit and creating economic benefits.

[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 13 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 embodiment, the carbon dioxide low-pressure adsorption long-term energy storage system includes a fourth heat exchanger 8, a high-pressure liquefied storage tank 10, a seventh heat exchanger 12, a turbine 13 and an adsorption tower 3 connected in sequence along the flow direction; the adsorption tower 3 is also bidirectionally connected to the sixth heat exchanger 11 and the first heat exchanger 1. The system is composed of a carbon dioxide adsorption tower 3, multiple heat exchangers, a turbine 13, a methanol production device 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 in the energy storage stage to desorb the carbon dioxide stored therein and send 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 13 does work, and adsorbs and stores it. The high-pressure liquefied storage tank 10 receives and stores the pressurized and cooled carbon dioxide for use in the energy release stage. The turbine 13 is connected to a generator to receive the high-pressure and high-temperature carbon dioxide for expansion and power generation, and the expanded low-pressure carbon dioxide returns to the adsorption tower 3 for adsorption and storage again. The compressor 6 and turbine 13 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, a fifth heat exchanger 9 is provided between the fourth heat exchanger 8 and the high-pressure liquefied storage tank 10; the first heat exchanger 1 is bidirectionally connected to the second heat exchanger 2. The additional heat exchange step can achieve more sophisticated energy management, effective cascade utilization of energy in each link, and full utilization of waste heat or low-temperature energy in the system, effectively improving system efficiency.

[0026] As another specific implementation, the third heat exchanger 4, the fifth heat exchanger 9 and the second heat exchanger 2 are bidirectionally connected to the turbine condensate line; the CCUS carbon dioxide reduction device 5, the sixth heat exchanger 11 and the seventh heat exchanger 12 are bidirectionally connected to the boiler high-temperature flue gas line or the turbine high-temperature steam line; the first heat exchanger 1 and the fourth heat exchanger 8 are 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.

[0027] As another specific implementation, the sixth heat exchanger 11 and the seventh heat exchanger 12 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 producing methanol from coal-fired power CCUS coupled with adsorption carbon dioxide energy storage includes the following switchable modes: Mode 1: Carbon capture to methanol mode; Mode 2: Carbon capture to methanol coupled with non-stop zero power supply mode; Mode 3: Carbon capture to produce methanol 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. It can also use the captured and compressed high-temperature carbon dioxide and green hydrogen to produce methanol to replace the traditional carbon dioxide cooling and liquefaction storage, thus realizing the green resource utilization of carbon dioxide and bringing 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 to release carbon dioxide, and then flows into the compressor 6 for pressurization after heat exchange with the turbine condensate through the third heat exchanger 4, and then enters the methanol production device 7 together with green hydrogen to prepare methanol. In this mode, only the CCUS carbon dioxide reduction device 5, the third heat exchanger 4, the compressor 6 and the methanol production device 7 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 sixth heat exchanger 11 and transported 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 to be pressurized by the compressor 6. A part of the pressurized carbon dioxide is used to prepare methanol with green hydrogen, and the other part is cooled and liquefied through the fourth heat exchanger 8 and the fifth heat exchanger 9 in sequence and stored in the high-pressure liquefied storage tank 10 to be used in the energy release stage. 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 10 without passing through the turbine 13, so no additional power is generated, and the high-pressure carbon dioxide in the high-pressure liquefied storage tank 10 provides a reserve for additional power generation.

[0033] As another specific implementation, in mode 3, based on mode 1, the high-pressure carbon dioxide in the high-pressure liquefied storage tank 10 absorbs heat through the seventh heat exchanger 12 and flows into the turbine 13 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 10 is passed through the turbine 13 to generate additional electricity, and the original generator set of the original coal-fired power unit is cooperated 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 system for producing methanol from coal-fired power CCUS coupled with adsorption-based carbon dioxide energy storage, characterized by: It includes a CCUS carbon dioxide reduction device, a third heat exchanger, a compressor and a methanol production device which are sequentially connected along the flow direction, and the input end of the CCUS carbon dioxide reduction device is connected to the boiler exhaust gas line; The input end of the methanol production device is connected to the compressor and the hydrogen input line, and the output end of the methanol production device is connected to the methanol output line; the compressor is 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 compressor to the upstream of the compressor. A valve is provided downstream of the compressor to respectively adjust the flow to the methanol production device and the carbon dioxide low-pressure adsorption long-term energy storage system.

2. The system for producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage according to claim 1, characterized in that: The carbon dioxide low-pressure adsorption long-term energy storage system includes a fourth heat exchanger, a high-pressure liquefied storage tank, a seventh 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 sixth heat exchanger and the first heat exchanger.

3. The system for producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage as claimed in claim 2, characterized in that: A fifth heat exchanger is provided between the fourth heat exchanger and the high-pressure liquefied storage tank; and the first heat exchanger is bidirectionally connected to the second heat exchanger.

4. The system for producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage as claimed in claim 3, characterized in that: The third heat exchanger, the fifth heat exchanger and the second heat exchanger are bidirectionally connected to the turbine condensate line; the CCUS carbon dioxide reduction device, the sixth heat exchanger and the seventh heat exchanger are bidirectionally connected to the boiler high-temperature flue gas line or the turbine high-temperature steam line; the first heat exchanger and the fourth heat exchanger are bidirectionally connected to the turbine feed water line.

5. The system for producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage as claimed in claim 4, characterized in that: The sixth heat exchanger and the seventh heat exchanger are bidirectionally connected to the same boiler high-temperature flue gas line or turbine high-temperature steam line.

6. A method for producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage, characterized in that: Includes the following modes that can be switched: Mode 1: Carbon capture to methanol mode; Mode 2: Carbon capture to methanol coupled with non-stop zero power supply mode; Mode 3: Carbon capture to produce methanol coupled with peak power generation mode.

7. The method for producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage according to 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 to release carbon dioxide. After passing through the third heat exchanger and the turbine condensate, it flows into the compressor for pressurization and then passes into the methanol production device together with green hydrogen to prepare methanol.

8. The method for producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage 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 producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage 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 sixth heat exchanger and transported to the adsorption tower to heat the adsorption tower, so that the carbon dioxide therein is desorbed and released, and is then fed into the compressor for pressurization together with the carbon dioxide from the CCUS carbon dioxide reduction device. Part of the pressurized carbon dioxide is reacted with green hydrogen to produce methanol, and the other part is cooled and liquefied through the fourth heat exchanger and the fifth heat exchanger in turn, and then stored in a high-pressure liquefied storage tank to be used in the energy release stage.

10. The method for producing methanol from coal-fired power CCUS coupled with adsorption-type carbon dioxide energy storage according to claim 6, characterized in that: In mode 3, based on mode 1, the high-pressure carbon dioxide in the high-pressure liquefied storage tank absorbs heat through the seventh 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, awaiting the next energy storage use.

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