System for treating coal-based solid waste through LOHC energy storage coupling coal-fired boiler

Abstract

The embodiment of the invention provides a system for treating coal-based solid waste by coupling LOHC energy storage with a coal-fired boiler. The system comprises a boiler, a water electrolyzer, a hydrogen storage reactor, a dehydrogenation reactor and a coal mill, the renewable resource supplies power to the electrolyzed water device, and an anode outlet of the electrolyzed water device is connected with an over fire air nozzle of the boiler; a cathode outlet of the water electrolyzer is connected with a first inlet of the hydrogen storage reactor; a first inlet and a first outlet of the dehydrogenation reactor are respectively connected with an outlet of the hydrogen storage reactor and a hydrogen nozzle of the boiler; a second outlet of the dehydrogenation reactor is connected with a second inlet of the hydrogen storage reactor; and an outlet of the coal mill is connected with a coal-based solid waste nozzle of the boiler. According to the system, an LOHC energy storage system and a coal-fired boiler system are innovatively coupled, flexible energy input needed by rapid frequency modulation and peak regulation is provided for a thermal power generating unit through the hydrogen energy two-way conversion capacity of LOHC energy storage, and meanwhile the requirement for electricity abandoning hydrogen production is met.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of coal-fired power generation, and particularly relate to a system for disposing coal-based solid waste by coupling an LOHC energy storage with a coal-fired boiler. Background Art

[0002] In the fields of coal chemical industry and coal-fired power generation, semicoke gasification residue, as a typical representative of coal-based solid waste, faces severe challenges in large-scale disposal. Semicoke gasification residue is produced from processes such as coal pyrolysis and gasification, and has characteristics such as high ash content, low volatile content, and difficult burnout. Traditional landfill or co-firing methods are prone to cause secondary pollution, boiler efficiency decline, slagging and other problems. At the same time, with the rapid increase in the proportion of new energy power, thermal power units need to frequently adjust their loads to smooth out grid fluctuations. However, the inherent thermal inertia of coal-fired boilers makes it difficult for their response rate to match the deep peak shaving requirements, and frequent load changes exacerbate the contradiction of unstable combustion of coal-based solid waste. On the other hand, the phenomenon of large-scale curtailment of wind power, photovoltaic and other new energy is still prominent. The lack of an economical and efficient energy storage technology to convert surplus power into a stable energy carrier restricts the clean energy consumption capacity.

[0003] The technology of liquid organic hydrogen carrier (LOHC) has become a potential solution to the above problems due to its high hydrogen storage density, long-cycle energy storage capacity, and compatibility with existing petrochemical facilities. LOHC realizes hydrogen energy storage and release through reversible hydrogenation and dehydrogenation reactions. Its energy storage density can reach more than 60 kWh / L, and it is in a liquid state at normal temperature and pressure, with significantly better safety than high-pressure hydrogen storage. During the period of new energy curtailment, hydrogen can be produced by electrolyzing water and stored in LOHC; during the peak grid load, high-purity hydrogen is released through the dehydrogenation reaction, which can not only assist the coal-fired boiler to quickly increase the load (the hydrogen combustion rate is 8-10 times that of pulverized coal), but also serve as a combustion improver for semicoke residue to improve its combustion characteristics. In particular, the exothermic characteristics (200°C - 300°C) of the LOHC dehydrogenation process can match the temperature of the flue gas in the boiler tail flue, improving the system energy efficiency.

[0004] Currently, there is no report on coupling an LOHC energy storage system with a coal-fired boiler for disposing coal-based solid waste. Summary of the Invention

[0005] The embodiments of the present disclosure aim to at least solve one of the technical problems existing in the prior art, and provide a system for disposing coal-based solid waste by coupling an LOHC energy storage with a coal-fired boiler.

[0006] The embodiments of the present disclosure provide a system for disposing coal-based solid waste by coupling an LOHC energy storage with a coal-fired boiler, including a boiler, an electrolyzer, a hydrogen storage reactor, a dehydrogenation reactor, and a coal mill;

[0007] Renewable resources supply power to the electrolyzer, and the anode outlet of the electrolyzer is connected to the burnout air nozzle of the boiler;

[0008] The cathode outlet of the electrolyzer is connected to the first inlet of the hydrogen storage reactor to react the hydrogen generated by electrolysis with an organic compound in the hydrogen storage reactor to form and store a liquid organic hydrogen carrier.

[0009] The first inlet and the first outlet of the dehydrogenation reactor are respectively connected to the outlet of the hydrogen storage reactor and the hydrogen injection nozzle of the boiler to transport the hydrogen generated by the dehydrogenation reaction of the liquid organic hydrogen carrier to the boiler.

[0010] The second outlet of the dehydrogenation reactor is connected to the second inlet of the hydrogen storage reactor to transport the organic compound generated by the dehydrogenation reaction of the liquid organic hydrogen carrier to the hydrogen storage reactor.

[0011] The outlet of the coal mill is connected to the coal-based solid waste injection nozzle of the boiler to transport the pulverized coal-based solid waste fuel to the boiler.

[0012] Optionally, the system further includes an oxygen storage tank and a first gas mixer.

[0013] The inlet and the outlet of the oxygen storage tank are respectively connected to the anode outlet of the electrolyzer and the inlet of the first gas mixer, and the outlet of the first gas mixer is connected to the overfire air injection nozzle of the boiler.

[0014] Optionally, the system further includes a second gas mixer.

[0015] The inlets of the second gas mixer are respectively connected to the bottom flue gas and the tail flue gas of the boiler, and the outlet of the second gas mixer is connected to the second inlet of the dehydrogenation reactor.

[0016] Optionally, the system further includes a first induced draft fan.

[0017] The first induced draft fan is arranged in the pipeline between the second gas mixer and the bottom of the boiler.

[0018] Optionally, the third outlet of the dehydrogenation reactor is connected to the tail flue before the air preheater in the boiler.

[0019] Optionally, the system further includes a second induced draft fan, and the second induced draft fan is arranged in the pipeline between the dehydrogenation reactor and the tail flue before the air preheater in the boiler.

[0020] Optionally, the system further includes a forced draft fan, and the forced draft fan is connected to the air preheater.

[0021] Optionally, the system further includes a steam turbine and a generator.

[0022] The steam turbine is respectively connected to the boiler and the generator, and the generator is connected to the electrolyzer to supply power to the electrolyzer.

[0023] Optionally, the system further includes a hydrogen storage tank, and the inlet and outlet of the hydrogen storage tank are respectively connected to the cathode outlet of the electrolyzer and the inlet of the hydrogen storage reactor.

[0024] Optionally, the system further includes a dust collector, a third induced draft fan and a chimney;

[0025] The inlet and outlet of the dust collector are respectively connected to the tail flue of the boiler and the inlet of the third induced draft fan, and the outlet of the third induced draft fan is connected to the inlet of the chimney.

[0026] The system for disposing coal-based solid waste by coupling LOHC energy storage with a coal-fired boiler according to the embodiments of the present disclosure innovatively couples the LOHC energy storage system with the coal-fired boiler system. Through the bidirectional hydrogen energy conversion ability of LOHC energy storage, it provides flexible energy input required for rapid frequency modulation and peak shaving of thermal power units, and at the same time consumes the hydrogen production demand from abandoned electricity; this system breaks through the single-dimensional optimization mode of traditional solid waste disposal and thermal power peak shaving, and forms a multi-objective collaborative solution among coal-based solid waste resource utilization, improvement of thermal power flexibility, and new energy consumption. Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of a system for disposing coal-based solid waste by coupling LOHC energy storage with a coal-fired boiler according to an embodiment of the present disclosure. Detailed Embodiments

[0028] To enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, the following further describes the embodiments of the present disclosure in detail with reference to the drawings and specific embodiments.

[0029] As Figure 1 shown, the embodiments of the present disclosure provide a system for disposing coal-based solid waste by coupling LOHC energy storage with a coal-fired boiler, including a boiler 1, an electrolyzer 2, a hydrogen storage reactor 3, a dehydrogenation reactor 4 and a coal mill 5.

[0030] Renewable resources supply power to the electrolyzer 2, and the anode outlet of the electrolyzer 2 is connected to the burnout air nozzle 6 of the boiler 1 to deliver the oxygen generated by electrolysis as a combustion aid to the furnace of the boiler 1 for combustion.

[0031] In this embodiment, the redundant power generation of renewable resources is used to supply power to the electrolyzer 2, reducing the power consumption of the system and the carbon emissions of the system. Among them, the renewable resources can be wind power or photovoltaic power generation. Using the oxygen generated by electrolysis as a combustion aid for furnace combustion further reduces the carbon emissions of the system.

[0032] The cathode outlet of the electrolyzer 2 is connected to the first inlet of the hydrogen storage reactor 3 to react the hydrogen generated by electrolysis with an organic compound in the hydrogen storage reactor 3 to form and store a liquid organic hydrogen carrier. Among them, the liquid organic hydrogen carrier can be stored in the hydrogen storage reactor 3 for a long time.

[0033] In this embodiment, the use of liquid organic hydrogen carrier technology for energy storage can achieve stable and efficient long-term energy storage, and can transport energy to other power plant boilers, optimizing China's energy structure.

[0034] The first inlet and the first outlet of the dehydrogenation reactor 4 are respectively connected to the outlet of the hydrogen storage reactor 3 and the hydrogen injection port 7 of the boiler 1 to transport the hydrogen generated by the dehydrogenation reaction of the liquid organic hydrogen carrier to the boiler 1.

[0035] Specifically, when the unit needs hydrogen for combustion, the liquid organic hydrogen carrier in the hydrogen storage reactor 3 is introduced into the dehydrogenation reactor 4 for dehydrogenation reaction, and the generated hydrogen enters the boiler 1 through the hydrogen injection port 7 as a combustion aid for combustion.

[0036] In this embodiment, when the unit needs to quickly increase the load, the energy release intensity of the dehydrogenation reactor 4 can be increased, the intensity of the dehydrogenation reaction can be increased, and the heat generated by hydrogen combustion can be used to quickly increase the furnace heat load, thereby increasing the power generation load.

[0037] The second outlet of the dehydrogenation reactor 4 is connected to the second inlet of the hydrogen storage reactor 3 to transport the organic compound generated by the dehydrogenation reaction of the liquid organic hydrogen carrier to the hydrogen storage reactor 3.

[0038] Specifically, the organic compound generated by the dehydrogenation reaction of the liquid organic hydrogen carrier introduced into the dehydrogenation reactor 4 is transported into the hydrogen storage reactor 3, where it can continue to react with hydrogen to generate a liquid organic hydrogen carrier for hydrogen storage.

[0039] The outlet of the coal mill 5 is connected to the coal-based solid waste injection port 8 of the boiler 1 to transport the pulverized coal-based solid waste fuel to the boiler. Specifically, the coal mill 5 pulverizes the coal-based solid waste fuel and sends it into the furnace of the boiler 1 through the coal-based solid waste injection port 8 for combustion.

[0040] As Figure 1 shown, the boiler 1 further includes a pulverized coal injection port 9, and the coal-based solid waste injection port 8 is arranged between the hydrogen injection port 7 and the pulverized coal injection port 9.

[0041] In this embodiment, the hydrogen released by the dehydrogenation reactor 4 is used to combust and assist in burning the coal-based solid waste fuel in the boiler, and the coal-based solid waste injection port 8 is arranged between the hydrogen injection port 7 and the pulverized coal injection port 9, and the heat released by the combustion of pulverized coal and hydrogen is used together to assist in burning the coal-based solid waste fuel.

[0042] The system for disposing coal-based solid waste by coupling LOHC energy storage with a coal-fired boiler according to an embodiment of the present disclosure innovatively couples an LOHC energy storage system with a coal-fired boiler system. Through the bidirectional hydrogen energy conversion ability of LOHC energy storage, it provides flexible energy input required for rapid frequency regulation and peak shaving of thermal power units, and at the same time accommodates the demand for hydrogen production from abandoned electricity. This system breaks through the single-dimensional optimization mode of traditional solid waste disposal and thermal power peak shaving, and forms a multi-objective collaborative solution among the resource utilization of coal-based solid waste, the improvement of thermal power flexibility, and the accommodation of new energy.

[0043] Exemplarily, as Figure 1 shown, the system further includes an oxygen storage tank 10 and a first gas mixer 11.

[0044] The inlet and outlet of the oxygen storage tank 10 are respectively connected to the anode outlet of the electrolyzer 2 and the inlet of the first gas mixer 11, and the outlet of the first gas mixer 11 is connected to the burnout air nozzle 6 of the boiler 1.

[0045] Specifically, the oxygen electrolyzed by the electrolyzer 2 is transported into the oxygen storage tank 10 for storage. The oxygen in the oxygen storage tank 10 is mixed with air in the first gas mixer 11 to obtain oxygen-enriched burnout air, which is sent into the furnace of the boiler 1 through the burnout air nozzle 6 for combustion.

[0046] In this embodiment, the oxygen-enriched burnout air with the ratio of oxygen generated by the electrolyzer to air is used to improve the burnout rate of the mixed fuel.

[0047] Exemplarily, the system further includes a second gas mixer 12. The inlets of the second gas mixer 12 are respectively connected to the bottom flue gas of the boiler 1 and the tail flue gas of the boiler, and the outlet of the second gas mixer 12 is connected to the second inlet of the dehydrogenation reactor 4.

[0048] Specifically, the system further includes a first induced draft fan 13, which is arranged in the pipeline between the second gas mixer 12 and the bottom of the boiler 1. The bottom flue gas is induced to the second gas mixer 12 by the first induced draft fan 13. The bottom flue gas and the tail flue gas of the boiler are mixed in the second gas mixer 12 to provide heat for the chemical reaction in the dehydrogenation reactor 4.

[0049] In this embodiment, the two-medium furnace flue gas mixing system composed of high-temperature bottom flue gas and low-temperature tail flue gas can provide the necessary reaction temperature for energy release of the dehydrogenation reactor and can be flexibly adjusted according to the reaction temperature.

[0050] Exemplarily, as Figure 1 shown, the third outlet of the dehydrogenation reactor 4 is connected to the tail flue before the air preheater 14 in the boiler 1.

[0051] Specifically, the system further includes a second induced draft fan 15, which is arranged in the pipeline between the dehydrogenation reactor 4 and the tail flue before the air preheater 14 in the boiler. After the mixed flue gas is used for heat exchange to supply heat to the dehydrogenation reactor 4, the heat-exchanged mixed flue gas is sent into the tail flue before the air preheater 14 through the second induced draft fan 15.

[0052] In this embodiment, for the mixed flue gas after supplying heat to the dehydrogenation reactor 4, the second induced draft fan 15 is used to introduce it into the tail flue before the air preheater 14 to increase the heat of the flue gas in the tail flue and improve the efficiency of the air preheater.

[0053] Exemplarily, as Figure 1 shown, the system further includes a forced draft fan 16, and the forced draft fan 16 is connected to the air preheater 14. The forced draft fan 16 sends primary air, secondary air, and burnout air into the air preheater 14 for preheating.

[0054] Exemplarily, as Figure 1 shown, the system further includes a steam turbine 17 and a generator 18. The steam turbine 17 is respectively connected to the boiler 1 and the generator 18, and the generator 18 is connected to the electrolyzer 2 to supply power to the electrolyzer 2.

[0055] Specifically, the heat generated by the combustion of the boiler 1 drives the steam turbine 17 to rotate, thereby driving the generator 18 to generate electricity. When the unit needs to quickly reduce the load, the excess electric energy generated by the generator 18 is used to supply power to the electrolyzer 2 to produce hydrogen, and then the hydrogen is stored through the hydrogen storage reactor 3. At this time, a large change in the boiler heat load is avoided.

[0056] Exemplarily, as Figure 1 shown, the system further includes a hydrogen storage tank 19. The inlet and outlet of the hydrogen storage tank 19 are respectively connected to the cathode outlet of the electrolyzer 3 and the inlet of the hydrogen storage reactor 3.

[0057] Specifically, the hydrogen generated by the electrolysis of the electrolyzer 3 is transported to the hydrogen storage tank 19 for storage. When long-term storage of hydrogen is required, the hydrogen in the hydrogen storage tank 19 is transported to the hydrogen storage reactor 3, and the hydrogen reacts with the organic compound in the hydrogen storage reactor 3 to form a liquid organic hydrogen carrier for storage.

[0058] Exemplarily, as Figure 1 shown, the system further includes a dust collector 20, a third induced draft fan 21, and a chimney 22. The inlet and outlet of the dust collector 20 are respectively connected to the tail flue of the boiler 1 and the inlet of the third induced draft fan 21, and the outlet of the third induced draft fan 21 is connected to the inlet of the chimney 22.

[0059] Specifically, the flue gas generated by the combustion of the boiler 1 can be discharged after dust removal in the dust collector 20, passing through the third induced draft fan 21 and the chimney 22.

[0060] As Figure 1 shown, the operation process of the system for disposing coal-based solid waste by coupling LOHC energy storage with a coal-fired boiler according to the embodiments of the present disclosure can be as follows:

[0061] 1) Use the redundant power generation of wind power generation and photovoltaic power generation to electrolyze water in the electrolyzer 2, and the generated O2(g) and H2(g) are stored in the oxygen storage tank 10 and the hydrogen storage tank 19 respectively.

[0062] 2) When the unit needs to quickly reduce the load, the redundant power that cannot be fed into the grid generated by the generator 18 is still used for the electrolysis reaction in the electrolyzer 2, and at the same time, the generated O2(g) and H2(g) are respectively introduced into the oxygen storage tank 10 and the hydrogen storage tank 19 for storage.

[0063] 3) The H2 in the hydrogen storage tank 19 combines with the organic compound in the hydrogen storage reactor 3 to form a liquid organic hydrogen carrier, which can be stored for a long time.

[0064] 4) When the unit needs H2(g) for combustion, the liquid organic hydrogen carrier is fed into the dehydrogenation reactor 4 for a chemical reaction.

[0065] 5) The first induced draft fan 13 mixes the bottom flue gas and the tail flue gas in the second gas mixer 12, and then provides heat for the chemical reaction in the dehydrogenation reactor 4. The mixed flue gas after heat exchange is sent into the tail flue before the air preheater 14 through the second induced draft fan 15.

[0066] 6) The H2(g) generated by the dehydrogenation reactor 4 is sent into the furnace for combustion through the hydrogen nozzle 7, while the coal-based solid waste fuel is pulverized in the coal mill 5 and sent into the furnace for combustion through the coal-based solid waste nozzle 8.

[0067] 7) The O2(g) in the oxygen storage tank 10 is mixed with air in the first gas mixer 11 to obtain oxygen-enriched burnout air, which is sent into the furnace for combustion through the burnout air nozzle 6.

[0068] 8) When the unit needs to quickly increase the load, the chemical reaction rate of the dehydrogenation reactor 4 can be increased, and the flow rate of the bottom flue gas can be increased by increasing the output of the first induced draft fan 13, so as to fully provide the heat required for the chemical reaction in the dehydrogenation reactor 4.

[0069] 9) The heat generated by the boiler combustion drives the steam turbine 17 to rotate, thereby driving the generator 18 to generate electricity.

[0070] 10) The flue gas generated by the combustion of the boiler 1 can be dust-removed in the dust collector 20 and then discharged through the third induced draft fan 21 and the chimney 22.

[0071] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the embodiments of the present disclosure. However, the embodiments of the present disclosure are not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the embodiments of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the embodiments of the present disclosure.

Claims

1. A system for treating coal-based solid waste by coupling LOHC energy storage with coal-fired boilers, characterized in that: It includes boiler, water electrolyzer, hydrogen storage reactor, dehydrogenation reactor and coal mill; The water electrolyzer is powered by renewable resources, and the anode outlet of the water electrolyzer is connected to the overburnt air nozzle of the boiler; The cathode outlet of the water electrolyzer is connected to the first inlet of the hydrogen storage reactor so that the hydrogen generated by electrolysis reacts with the organic compound in the hydrogen storage reactor to form a liquid organic hydrogen carrier and store it; The first inlet and the first outlet of the dehydrogenation reactor are respectively connected to the outlet of the hydrogen storage reactor and the hydrogen nozzle of the boiler, so as to transport the hydrogen generated by the dehydrogenation reaction of the liquid organic hydrogen carrier to the boiler; The second outlet of the dehydrogenation reactor is connected to the second inlet of the hydrogen storage reactor to transport the organic compound generated by the dehydrogenation reaction of the liquid organic hydrogen carrier to the hydrogen storage reactor; The outlet of the coal mill is connected to the coal-based solid waste outlet of the boiler so as to crush the coal-based solid waste fuel and then transport it to the boiler.

2. The system according to claim 1, characterized in that The system also includes an oxygen reservoir and a first gas mixer; The inlet and outlet of the oxygen storage are respectively connected to the anode outlet of the water electrolyzer and the inlet of the first gas mixer, and the outlet of the first gas mixer is connected to the overfire air nozzle of the boiler.

3. The system according to claim 1, characterized in that The system also includes a second gas mixer; The inlet of the second gas mixer is connected to the bottom flue gas of the boiler and the tail flue gas of the boiler respectively, and the outlet of the second gas mixer is connected to the second inlet of the dehydrogenation reactor.

4. The system according to claim 3, characterized in that The system also includes a first induced draft fan; The first induced draft fan is arranged in a pipeline between the second gas mixer and the furnace bottom of the boiler.

5. The system according to claim 3, characterized in that The third outlet of the dehydrogenation reactor is connected to the tail flue before the air preheater in the boiler.

6. The system according to claim 5, characterized in that The system further comprises a second induced draft fan, which is arranged in a pipeline between the dehydrogenation reactor and a tail flue in front of the air preheater in the boiler.

7. The system according to claim 6, characterized in that The system further comprises an air blower connected to the air preheater.

8. The system according to any one of claims 1 to 6, characterized in that: The system also includes a steam turbine and a generator; The steam turbine is connected to the boiler and the generator respectively, and the generator is connected to the water electrolyzer to supply power to the water electrolyzer.

9. The system according to any one of claims 1 to 6, characterized in that: The system further comprises a hydrogen storage device, wherein an inlet and an outlet of the hydrogen storage device are respectively connected to the cathode outlet of the water electrolyzer and the inlet of the hydrogen storage reactor.

10. The system according to any one of claims 1 to 6, characterized in that: The system also includes a dust collector, a third induced draft fan and a chimney; The inlet and outlet of the dust collector are respectively connected to the tail flue of the boiler and the inlet of the third induced draft fan, and the outlet of the third induced draft fan is connected to the inlet of the chimney.

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