Coal-electricity smoke exhaust methanol preparation and carbon dioxide energy storage integrated system and control method thereof

Abstract

The invention discloses an integrated system for methanol production and carbon dioxide energy storage through coal power exhaust smoke and a control method of the integrated system, and relates to the technical field of energy conservation, carbon reduction, energy storage and the like of coal power units, in particular to the integrated system for methanol production and carbon dioxide energy storage through coal power exhaust smoke and the control method of the integrated system. Comprising an adsorption separation tower module, a compressor, a methanol preparation device and a turbine in sequence, and the boiler smoke exhaust pipeline is connected between the turbine and the adsorption separation tower module; comprising a hydrogen production device, and a plurality of heat exchangers are respectively arranged between a boiler smoke exhaust pipeline and an adsorption separation tower module and between a methanol production device and a turbine. The method has the advantages that the flexibility and operation efficiency of a coal power unit are improved, the operation cost is reduced, economic benefits are increased, and novel coal power construction requirements are met; efficient carbon capture and green resource utilization are achieved, carbon emission is reduced, carbon neutralization target implementation is assisted, the technology is innovated, and energy transformation is promoted.

Description

Technical Field

[0001] The present invention relates to the technical fields of energy conservation, carbon reduction, energy storage and the like of coal-fired power units, and in particular to an integrated system for producing methanol from coal-fired power exhaust gas and storing carbon dioxide and a control method thereof. Background Art

[0002] As the construction of new power systems accelerates, coal-fired power units face many challenges: Requirements for new coal-fired power: With the increase in the amount of renewable energy such as wind power and solar power, which have intermittent and unstable characteristics, 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 shutdown. Due to the maximum evaporation capacity of the boiler, the peak capacity in summer is also relatively limited.

[0003] Carbon emission problem: Coal-fired power units are one of the main sources of carbon emissions, and there is an urgent need to develop effective carbon emission reduction technologies.

[0004] Carbon capture technology bottleneck: Although carbon capture and storage (CCUS) technology is considered one of the important means of carbon emission reduction, it has the following problems: Limited capture capacity: Traditional CCUS technology has limited scalability and cannot fully capture the carbon dioxide emitted by coal-fired power units.

[0005] High economic cost: The implementation and maintenance of CCUS technology requires high economic costs, which increases the operating burden of coal-fired power units.

[0006] Difficulty in resource utilization: The captured carbon dioxide usually needs to be cooled, liquefied and stored, making it difficult to achieve resource utilization.

[0007] Therefore, in order to solve the above problems, it is particularly urgent to develop a new technology that can improve the flexibility of coal-fired power units and realize carbon capture and resource utilization. This patent application proposes an integrated system of coal-fired power exhaust methanol production and carbon dioxide energy storage, which aims to effectively improve the deep peak regulation and peak output capacity of the unit through innovative technical means, realize the non-stop zero power supply operation of coal-fired power units, realize energy conservation, emission reduction and resource utilization of coal-fired power units, and improve the operating efficiency and economic benefits of the power system. Summary of the invention

[0008] The present invention aims to overcome the above-mentioned shortcomings of the prior art and provide an integrated system for producing methanol from coal-fired power plant exhaust gas and storing carbon dioxide and a control method thereof.

[0009] The technical solution adopted by the present invention is as follows: A coal-fired power plant exhaust gas methanol production and carbon dioxide energy storage integrated system, characterized in that it comprises: a boiler exhaust pipe, a plurality of heat exchangers and a circulation pipeline composed of an adsorption separation tower module, a compressor, a methanol production device and a turbine in sequence, wherein the boiler exhaust pipe is connected between the turbine and the adsorption separation tower module; The multiple heat exchangers are respectively arranged between the boiler exhaust pipe and the adsorption separation tower module, and between the compressor and the turbine; and the circulation pipeline is provided with multiple one-way valves.

[0010] Furthermore, it comprises a hydrogen production device, the methanol production device is provided with a hydrogen input pipe and an output pipe, the hydrogen production device is connected to the hydrogen input pipe, and the electricity consumed by the hydrogen production device is provided by green electricity such as abandoned wind and solar power (if there is no green electricity, it can also be provided by the system).

[0011] Furthermore, the adsorption separation tower module includes at least two adsorption separation towers, an inter-tower heat exchanger is provided between the adsorption separation towers, and the adsorption separation tower module is independently provided with a smoke inlet and a smoke outlet outside the circulation pipeline.

[0012] Furthermore, it also includes a high-pressure storage tank, which is arranged between the turbine and the methanol production device, and a heat exchanger is arranged at the air inlet end.

[0013] Furthermore, it also includes a bypass pipeline, which connects the heat exchanger at the compressor outlet and the turbine inlet, and the bypass pipeline is provided with a bypass valve.

[0014] Furthermore, a plurality of heat exchangers are separately provided with heat exchange pipelines outside the circulation pipeline.

[0015] Furthermore, it includes a control system, a boiler exhaust pipe, a heat exchanger, an adsorption separation tower module, a compressor, a bypass valve, a one-way valve, a hydrogen production device and a methanol production device, and the like are electrically connected to the control system.

[0016] Furthermore, a control method for an integrated system of coal-fired power plant exhaust gas methanol production and carbon dioxide energy storage comprises the following steps: S1: When the system is first started, the flue gas from the boiler is cooled by heat exchange with the heat exchanger and the condensate of the steam turbine and then flows into the adsorption separation tower module. The carbon dioxide in the flue gas is adsorbed and the remaining gas is discharged through the smoke outlet; S2: When one of the adsorption separation towers is saturated, the control system switches the flue gas to another adsorption separation tower to start adsorption separation; S3: A stream of flue gas / steam is introduced from the flue gas inlet into the adsorption separation tower with saturated adsorption to increase its temperature, during which carbon dioxide is desorbed and flows into the compressor for pressurization and temperature increase. Subsequently, the control system starts the hydrogen production device to introduce hydrogen and carbon dioxide into the methanol production device to prepare methanol; the carbon dioxide used for power generation is stored in a high-pressure storage tank after passing through a heat exchanger; S4: When desorption is completed in one of the adsorption separation towers, the other adsorption separation tower completes adsorption. The control system transfers the heat of the adsorption separation tower that has completed desorption to the adsorption separation tower to be desorbed through the inter-tower heat exchanger, so that the carbon dioxide therein starts to be desorbed and input into the compressor for pressure increase. At the same time, the adsorption separation tower that has completed desorption cools down and starts to adsorb carbon dioxide in the flue gas again, and the cycle repeats. S5: In the subsequent operation, due to the inevitable heat exchange loss in the inter-tower heat exchanger, the control system adds flue gas / steam through the smoke inlet to supplement the heat of the adsorption separation tower module after one heat exchange in the inter-tower heat exchanger.

[0017] Furthermore, when the coal-fired power generation unit is in zero-power operation, on the basis of carbon capture and methanol production operation, all the electricity of the coal-fired power generation unit after deducting the factory power consumption is used for the compressor (4) and the hydrogen production device (13), so as to achieve zero-power operation without stopping; the control system adjusts the hydrogen production rate of the hydrogen production device (13) and the power of the compressor (4), so that the flow rates of hydrogen and carbon dioxide flowing into the methanol production device (6) are matched, and at the same time adjusts the flue gas volume input to the system to ensure that the adsorption and desorption rates of the two towers in the system remain consistent.

[0018] Furthermore, when the coal-fired power unit is running at its peak, the control system controls the carbon dioxide stored in the high-pressure storage tank to flow into the turbine for expansion to generate power after absorbing heat through the heat exchanger; at the same time, the control system adjusts the valve to adjust the flow ratio of the compressor inlet gas to the methanol production device and the bypass pipeline. The carbon dioxide flowing into the bypass pipeline also flows into the turbine for expansion to generate power after absorbing heat through the heat exchanger. The maximum amount of compressor inlet gas can flow into the bypass pipeline, and the low-pressure carbon dioxide that has done work is circulated again in the pipeline. At this time, the input flue gas flow is adjusted to keep the adsorption rate and desorption rate of the two towers consistent.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. Efficient carbon capture and resource utilization: The system can achieve efficient adsorption, separation and compression of carbon dioxide (CO2) in boiler exhaust. By rationally utilizing the high-temperature carbon dioxide after compression and heating and green hydrogen produced by green electricity to produce methanol, it not only effectively reduces carbon emissions, but also converts carbon dioxide into high-value-added chemicals, realizing the green resource utilization of carbon dioxide. Compared with the traditional carbon dioxide cooling and liquefaction storage method, this method has higher economic and environmental benefits.

[0020] 2. Improve the flexibility and operating efficiency of coal-fired power units: The system allows coal-fired power units to operate under low load or even zero power supply conditions. By using all the output after deducting the factory power consumption to drive the compressor, it realizes non-stop zero power supply operation. This feature avoids a large amount of energy loss during the start-up and shutdown process of coal-fired power units, and improves the operating efficiency and economic benefits of the system. At the same time, the system can quickly adjust the operating mode when necessary to adapt to changes in demand in the power market, which improves the flexibility of coal-fired power units.

[0021] 3. Reduce operating costs and increase economic benefits: During the operation of the system, if the power plant can use low-cost wind power or photovoltaic power that cannot be connected to the grid as the power source for the compressor, it can further reduce operating costs and improve economic benefits. In addition, when it is necessary to increase peak output, the system can generate electricity through turbines to connect to the grid, converting low-cost wind power or photovoltaic power that cannot be connected to the grid into high-quality electricity to connect to the grid, bringing higher economic benefits to the power plant.

[0022] 4. Reduce carbon emissions: Through efficient carbon capture and resource utilization technology, the system significantly reduces carbon emissions from coal-fired power units, contributing to global climate change response.

[0023] 5. Technological innovation promotes energy transformation: The coal-fired power exhaust methanol production and carbon dioxide energy storage integrated system proposed in this invention is an innovative technology integration, which organically combines carbon capture, methanol production and energy storage. This technological innovation provides new ideas and methods for the transformation and upgrading of coal-fired power units, and promotes the optimization of energy structure and the sustainable development of power systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the present invention; Markings in the figure: 1-circulation pipeline, 2-adsorption separation tower module, 3-adsorption separation tower, 4-compressor, 5-heat exchanger, 6-methanol production unit, 7-turbine, 8-boiler exhaust pipe, 9-inter-tower heat exchanger, 10-smoke inlet, 11-smoke outlet, 12-heat exchange pipeline, 13-hydrogen production unit, 14-hydrogen input pipe, 15-output pipe, 16-high-pressure storage tank, 17-bypass pipeline. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] Embodiment 1 In this embodiment, if Figure 1 As shown, a coal-fired power exhaust methanol production and carbon dioxide energy storage integrated system includes: a boiler exhaust pipe 8, a plurality of heat exchangers 5 and a circulation pipeline 1 composed of an adsorption separation tower module 2, a compressor 4, a methanol production device 6 and a turbine 7 in sequence, and the boiler exhaust pipe 8 is connected between the turbine 7 and the adsorption separation tower module 2; The plurality of heat exchangers 5 are respectively arranged between the boiler exhaust pipe 8 and the adsorption separation tower module 2 , and between the methanol production device 6 and the turbine 7 .

[0028] Specifically, the circulation pipeline 1 is arranged as follows: the turbine 7 is connected to the first heat exchanger 5, the first heat exchanger 5 is introduced into the turbine condensate through the heat exchange pipeline 12, the first heat exchanger 5 is connected to the adsorption separation tower module 2, the adsorption separation tower module 2 is connected to the compressor 4, the compressor 4 is connected to the methanol production device 6, the methanol production device 6 is connected to the hydrogen production device 13 through the hydrogen input pipe 14, the hydrogen production device 13 uses the coal-fired power unit or the clean energy that cannot be connected to the grid as the energy to produce hydrogen, the compressor 4 is also connected to the second heat exchanger 5 through the bypass pipeline 17 and the high-pressure storage tank 16 respectively, the second heat exchanger 5 is introduced into the boiler high-temperature flue gas / turbine high-temperature steam through the heat exchange pipeline 12, and the second heat exchanger 5 is connected to the turbine 7 to form the circulation pipeline 1.

[0029] Furthermore, it includes a hydrogen production device 13 , and the methanol production device 6 is provided with a hydrogen input pipe 14 and an output pipe 15 , and the hydrogen production device 13 is connected to the hydrogen input pipe 14 .

[0030] The hydrogen production device 13 uses excess electricity generated by the power plant, or the power plant can use low-cost wind power and photovoltaic power that cannot be connected to the grid as a power source, and uses clean energy to produce hydrogen. The output hydrogen is connected to the methanol production device 6 to perform the methanol production step.

[0031] Furthermore, the adsorption separation tower module 2 includes at least two adsorption separation towers 3 , and an inter-tower heat exchanger 9 is disposed between the adsorption separation towers 3 .

[0032] In this embodiment, the adsorption separation tower module 2 includes two adsorption separation towers 3, and the two adsorption separation towers 3 are operated alternately. The carbon dioxide adsorption separation tower module 2 in the system includes two adsorption separation towers 3 arranged in parallel, and a heat exchanger 5 is arranged between the two towers to realize heat exchange between the two towers. The two towers alternately serve as the heat source for desorption of each other, and the module basically realizes internal heat self-sustaining, and completes the continuous carbon capture of the input exhaust gas. Among them, the adsorption separation tower module 2 realizes that the two towers alternately serve as cold / heat sources to each other by designing two towers in parallel and matching the inter-tower heat exchanger 9 and the corresponding pipeline connection of the valve, so as to realize the alternating operation of exhaust carbon dioxide adsorption separation and carbon dioxide desorption in the two groups of adsorption separation towers 3, thereby realizing the continuous and efficient carbon capture of the exhaust gas of the coal-fired power plant and producing methanol.

[0033] Furthermore, the adsorption separation tower module 2 is separately provided with a smoke inlet 10 and a smoke outlet 11 outside the circulation pipeline 1 .

[0034] The smoke inlet 10 is used to input high-temperature smoke / steam to supplement the heat of the adsorption separation tower module 2, and the smoke outlet 11 is used to discharge other gases after the adsorption of carbon dioxide, so as to fully utilize the hot steam of the steam turbine unit and improve the energy utilization efficiency.

[0035] Furthermore, the plurality of heat exchangers 5 are separately provided with a heat exchange pipeline 12 outside the circulation pipeline 1 .

[0036] Used to introduce boiler high-temperature flue gas / turbine high-temperature steam or turbine condensate, etc., to fully utilize the system heat and improve energy utilization efficiency.

[0037] Furthermore, including a control system, the boiler exhaust pipe 8, the heat exchanger 5, the adsorption separation tower module 2, the compressor 4, the hydrogen production device 13 and the methanol production device 6 turbine 7 are all electrically connected to the control system.

[0038] Used to control the overall system and perform different controls according to different power generation conditions.

[0039] Furthermore, the circulation pipeline 1 is provided with a plurality of one-way valves.

[0040] The flow direction of the circulation pipeline 1 is effectively controlled to improve the system operation efficiency.

[0041] Embodiment 2 A control method for an integrated system of methanol production from coal-fired power plant exhaust gas and carbon dioxide energy storage, comprising the following steps: S1: When the system is started for the first time, the flue gas from the boiler is cooled by heat exchange with the condensate of the steam turbine in the heat exchanger 5 and then flows into the adsorption separation tower module 2, the carbon dioxide in the flue gas is adsorbed, and the remaining gas is discharged through the smoke outlet 11; S2: When one of the adsorption separation towers 3 is saturated with adsorption, the control system switches the flue gas to another adsorption separation tower 3 to start adsorption separation; S3: A stream of high-temperature flue gas / steam is introduced from the smoke inlet 10 into the adsorption separation tower 3 which is saturated with adsorption to increase its temperature, wherein carbon dioxide is desorbed and flows into the compressor 4 for pressurization and temperature increase. Subsequently, the control system starts the hydrogen production device 13 to pass hydrogen and high-temperature carbon dioxide into the methanol production device 6 to prepare methanol; the high-pressure carbon dioxide used for power generation is stored in the high-pressure storage tank 16 after passing through the heat exchanger 5; S4: When the desorption of one of the adsorption separation towers 3 is completed, the other adsorption separation tower 3 is completed. The control system transfers the heat of the adsorption separation tower 3 that has completed desorption to the adsorption separation tower 3 to be desorbed through the inter-tower heat exchanger 9, so that the carbon dioxide therein starts to be desorbed and is input into the compressor 4 to complete liquefaction and storage. At the same time, the adsorption separation tower 3 that has completed desorption is cooled down and starts to adsorb carbon dioxide in the flue gas again, and the cycle repeats. S5: In the subsequent operation, due to the inevitable heat exchange loss in the inter-tower heat exchanger 9, the control system inputs high-temperature flue gas / steam through the smoke inlet 10 to supplement the heat of the adsorption separation tower module 2 after one heat exchange in the inter-tower heat exchanger 9.

[0042] Carbon capture to produce methanol: When the system is started for the first time, the flue gas from the boiler exhaust pipe 8 is cooled by heat exchange with the heat exchanger 5 and the turbine condensate, and then flows into the adsorption separation tower module 2. The carbon dioxide in the flue gas is adsorbed and the remaining gas is discharged. When the adsorption of the first adsorption separation tower 3 is completed, the control system switches the flue gas to flow into the second adsorption separation tower 3 to start adsorption separation; at the same time, a stream of high-temperature flue gas / steam is introduced into the first adsorption separation tower 3 to heat up the carbon dioxide in it and desorb it, and then flows into the compressor 4 for pressurization, and enters the methanol production device 6. The control system controls the hydrogen production device The device 13 starts to produce hydrogen, and after hydrogen is introduced, the methanol production device 6 starts to prepare methanol; when the first adsorption separation tower 3 is completely desorbed, the second adsorption separation tower 3 is also just adsorbed, and the flue gas is switched back to the first adsorption separation tower 3 again, and the heat in the first adsorption separation tower 3 is transported to the second adsorption separation tower 3 through the inter-tower heat exchanger 9, so that the carbon dioxide in the second adsorption separation tower 3 begins to desorb and enter the compressor 4, and at the same time, the first adsorption separation tower 3 starts to adsorb carbon dioxide in the flue gas after cooling, and the cycle is repeated to achieve continuous operation of flue gas carbon capture and methanol production. In the subsequent operation, due to the inevitable heat exchange loss of the inter-tower heat exchanger 9, high-temperature flue gas / steam is intermittently input to supplement the heat of the adsorption separation tower module 2.

[0043] This embodiment describes the technical details of the purification device used in the system. The purification device is used to purify the captured carbon dioxide and green hydrogen to remove impurities and pollutants. The purified raw gas can ensure the smooth progress of the methanol synthesis reaction and improve the purity and quality of the product.

[0044] The use of purification devices can improve the system's operational stability and product quality. At the same time, purification devices can also help reduce environmental pollution and equipment maintenance costs.

[0045] Embodiment 3 When the coal-fired power generation unit is in zero-power operation, on the basis of carbon capture and methanol production operation, all the electricity of the coal-fired power generation unit after deducting the factory power consumption is used for the compressor (4) and the hydrogen production device (13), so as to achieve zero-power operation without stopping; the control system adjusts the hydrogen production rate of the hydrogen production device (13) and the power of the compressor (4), so that the flow rates of hydrogen and carbon dioxide flowing into the methanol production device (6) are matched, and at the same time adjusts the flue gas volume input to the system to ensure that the adsorption and desorption rates of the two towers in the system remain consistent.

[0046] When the unit needs to be shut down due to the start-stop peak load regulation, the speed of compressor 4 is increased to increase the compression power. After the coal-fired power unit is reduced to the minimum load, the remaining output except for the factory power consumption is all used to drive the compressor 4 and the hydrogen production device 13, so that the coal-fired power unit can be operated without stopping and with zero power supply, thus avoiding the large amount of energy loss caused by the start-stop of the coal-fired power unit. The coal-fired power unit does not need to be shut down and only needs to operate at a 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 4, thereby improving the deep peak load regulation capability of the coal-fired power unit. The pressurized high-temperature carbon dioxide is made into methanol through the methanol production device 6.

[0047] Embodiment 4 During the peak operation of the coal-fired power unit: when the coal-fired power unit needs to increase the power generation, the energy release part of the system is put into operation, a stream of high-temperature flue gas / steam is introduced, and the control system controls the high-pressure carbon dioxide stored in the high-pressure storage tank 16 to flow into the turbine 7 for expansion and power generation after absorbing heat through the heat exchanger 5; at the same time, the control system adjusts the valve to adjust the flow ratio of the compressor 4 to the methanol production device 6 and the bypass pipeline 17, and the high-pressure carbon dioxide flowing into the bypass pipeline 17 also flows into the turbine 7 for expansion and power generation after absorbing heat through the heat exchanger 5, and the compressor 4 can flow into the bypass pipeline 17 at most. The low-pressure carbon dioxide that has done work is recycled again in the pipeline 1. According to the power plant ramp rate requirements, the turbine 7 can be in a shutdown or hot standby state when it is not generating electricity. By dynamically adjusting the flow distribution in different operating modes, the adsorption and desorption rates of the two adsorption separation towers 3 are kept consistent, thereby achieving continuous and stable operation of the system.

[0048] 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 4, the profit can be further improved. The power consumption of compressor 4 and hydrogen production device 13 is the 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.

[0049] The above description is only a preferred embodiment of the invention and is not intended to limit the invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the invention should be included in the protection scope of the invention.

Claims

1. A coal-fired power exhaust methanol production and carbon dioxide energy storage integrated system, characterized in that: include: A boiler exhaust pipe (8), a plurality of heat exchangers (5) and a circulation pipeline (1) which is sequentially composed of an adsorption separation tower module (2), a compressor (4), a methanol production device (6) and a turbine (7), wherein the boiler exhaust pipe (8) is connected between the turbine (7) and the adsorption separation tower module (2); The multiple heat exchangers (5) are respectively arranged between the boiler exhaust pipe (8) and the adsorption separation tower module (2), and between the compressor (4) and the turbine (7); and the circulation pipeline (1) is provided with multiple one-way valves.

2. According to the coal-fired power exhaust smoke methanol production and carbon dioxide energy storage integrated system as described in claim 1, it is characterized by: It comprises a hydrogen production device (13), the methanol production device (6) is provided with a hydrogen input pipe (14) and an output pipe (15), and the hydrogen production device (13) is connected to the hydrogen input pipe (14).

3. According to the coal-fired power exhaust smoke methanol production and carbon dioxide energy storage integrated system as described in claim 1, it is characterized by: The adsorption separation tower module (2) comprises at least two adsorption separation towers (3), an inter-tower heat exchanger (9) is arranged between the adsorption separation towers (3), and the adsorption separation tower module (2) is independently provided with a smoke inlet (10) and a smoke outlet (11) outside the circulation pipeline (1).

4. According to the coal-fired power exhaust smoke methanol production and carbon dioxide energy storage integrated system as described in claim 1, it is characterized by: It also includes a high-pressure storage tank (16), which is arranged between the turbine (7) and the compressor (4), and is provided with a heat exchanger (5) at the air inlet end.

5. According to the coal-fired power exhaust smoke methanol production and carbon dioxide energy storage integrated system as described in claim 1, it is characterized by: It also includes a bypass pipeline (17), wherein the bypass pipeline (17) connects the air outlet of the compressor (4) and the air inlet of the turbine (7), and the bypass pipeline (17) is provided with a bypass valve.

6. According to the coal-fired power exhaust smoke methanol production and carbon dioxide energy storage integrated system as described in claim 1, it is characterized by: The multiple heat exchangers (5) are independently provided with a heat exchange pipeline (12) outside the circulation pipeline (1).

7. According to the coal-fired power exhaust smoke methanol production and carbon dioxide energy storage integrated system as described in claim 2, it is characterized by: It comprises a control system, wherein the boiler smoke exhaust pipe (8), the heat exchanger (5), the adsorption separation tower module (2), the compressor (4), the one-way valve, the hydrogen production device (13), the methanol production device (6) and the turbine (7) are all electrically connected to the control system.

8. A control method for an integrated system of producing methanol from coal-fired power plant exhaust gas and storing carbon dioxide, applied to an integrated system of producing methanol from coal-fired power plant exhaust gas and storing carbon dioxide according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: When the system is started for the first time, the flue gas from the boiler is cooled by heat exchange with the condensate of the steam turbine in the heat exchanger (5) and then flows into the adsorption separation tower module (2). The carbon dioxide in the flue gas is adsorbed and the remaining gas is discharged through the smoke outlet (11); S2: When one of the adsorption separation towers (3) is saturated with adsorption, the control system switches the flue gas to another adsorption separation tower (3) to start adsorption separation; S3: A stream of flue gas / steam is introduced from the flue gas inlet (10) into the adsorption separation tower (3) which is saturated with adsorption, so that the temperature is increased, and the carbon dioxide is desorbed and flows into the compressor (4) to be pressurized and heated. Then the control system starts the hydrogen production device (13) to pass hydrogen and carbon dioxide into the methanol production device (6) to prepare methanol; the carbon dioxide used for power generation is stored in the high-pressure storage tank (16) after passing through the heat exchanger (5); S4: When desorption is completed in one of the adsorption separation towers (3), adsorption is completed in the other adsorption separation tower (3), and the control system transfers the heat of the adsorption separation tower (3) that has completed desorption to the adsorption separation tower (3) to be desorbed through the inter-tower heat exchanger (9), so that the carbon dioxide therein starts to be desorbed and is input into the compressor (4) for pressure increase. At the same time, the adsorption separation tower (3) that has completed desorption cools down and starts to adsorb carbon dioxide in the flue gas again, and the cycle repeats. S5: In subsequent operation, due to the inevitable heat exchange loss in the inter-tower heat exchanger (9), the control system inputs flue gas or steam through the smoke inlet (10) to supplement the heat of the adsorption separation tower module (2) after the inter-tower heat exchanger (9) performs a heat exchange.

9. The control method of the integrated system of methanol production and carbon dioxide energy storage by coal-fired power exhaust gas according to claim 8, characterized in that: When the coal-fired power generation unit is in zero-power operation, on the basis of carbon capture and methanol production operation, all the electricity of the coal-fired power generation unit after deducting the factory power consumption is used for the compressor (4) and the hydrogen production device (13), so as to achieve zero-power operation without stopping; the control system adjusts the hydrogen production rate of the hydrogen production device (13) and the power of the compressor (4), so that the flow rates of hydrogen and carbon dioxide flowing into the methanol production device (6) are matched, and at the same time adjusts the flue gas volume input to the system to ensure that the adsorption and desorption rates of the two towers in the system remain consistent.

10. The control method of the integrated system of methanol production and carbon dioxide energy storage based on coal-fired power exhaust gas according to claim 8, characterized in that: When the coal-fired power unit is in peak operation, the control system controls the carbon dioxide stored in the high-pressure storage tank (16) to flow into the turbine (7) to expand and generate power after absorbing heat through the heat exchanger (5); at the same time, the control system adjusts the valve to adjust the flow ratio of the incoming gas from the compressor (4) to the methanol production device (6) and the bypass pipeline (17), so that the carbon dioxide flowing into the bypass pipeline (17) also flows into the turbine (7) to expand and generate power after absorbing heat through the heat exchanger (5). At most, all the incoming gas from the compressor (4) can flow into the bypass pipeline (17), and the low-pressure carbon dioxide that has completed the work will be recycled to the circulation pipeline (1) again. At this time, the input flue gas flow is adjusted so that the adsorption rate and desorption rate of the two towers are consistent.

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