Multi-source synergistic hydrogen energy and coal chemical coupling method based on carbon-based solid waste

Abstract

The invention discloses a multi-source synergistic hydrogen energy and coal chemical industry coupling method based on carbon-based solid waste, and belongs to the cross technical field of hydrogen energy and coal chemical industry, the scheme is as follows: coal chemical industry carbon-based solid waste is combusted to generate power, coal chemical industry waste heat is utilized to generate power, and coal chemical industry secondary energy is formed; new energy power generation and coal chemical secondary energy power generation are coordinated to form an island micro-grid, so that the power demand of hydrogen production by electrolysis of water is met; when the new energy is insufficient in power supply, the coal chemical secondary energy is used for maintaining 20% low-load operation of the electrolytic bath; hydrogen generated in the hydrogen production electrolytic cell is sent to the coal chemical industry; and oxygen generated in the hydrogen production electrolytic cell is sent to oxygen-enriched combustion. The coal chemical secondary energy is used as the bottom energy, the defect that attenuation of an electrolytic cell is accelerated due to frequent starting and stopping of the electrolytic cell caused by the fact that new energy is used as intermittent energy is overcome, the problem that hydrogen production cost is high due to hydrogen production, energy storage or hydrogen power generation through water electrolysis of primary energy is solved, and meanwhile a new absorption path is provided for carbon-based solid waste discharged by the coal chemical industry.

Description

Technical Field

[0001] This invention relates to the field of interdisciplinary technology of hydrogen energy and coal chemical industry, and more specifically to a multi-source synergistic coupling method of hydrogen energy and coal chemical industry based on carbon-based solid waste. Background Technology

[0002] The coal chemical industry has long faced development challenges such as high carbon emissions, high dependence on fossil fuels, and the accumulation of carbon-based solid waste. Hydrogen energy, as a clean and efficient secondary energy source, offers a key path to overcoming development bottlenecks and promoting the industry's low-carbon transformation through deep integration with the coal chemical industry. The Ningdong Energy and Chemical Base possesses natural advantages for the coupled development of hydrogen energy and coal chemicals. However, in the process of promoting their deep integration, the intermittent and fluctuating nature of new energy sources (wind and solar) and the significantly higher cost of hydrogen production compared to ash hydrogen have hindered the slow progress of the coupling between the hydrogen energy industry and the coal chemical industry.

[0003] Waste heat power generation technology from coal chemical systems is mature, and many projects have been launched in China. Hydrogen production through water electrolysis is also relatively common domestically. Although some hydrogen energy coupled with coal chemical projects have been put into operation, due to the volatility and indirectness of new energy sources, these projects almost always operate during the day and shut down at night, resulting in frequent start-ups and shutdowns of the electrolyzers and severe lifespan reduction. Alternatively, electricity can be downloaded from the grid, or energy storage and hydrogen storage power generation devices can be added, leading to high hydrogen production costs and operating losses.

[0004] Therefore, providing a hydrogen energy and coal chemical coupling technology based on carbon-based solid waste, which integrates new energy sources with secondary energy sources in coal chemical industry, can truly solve the long-term, economically stable operation problems encountered in the coupling process of hydrogen energy and coal chemical industry, and significantly promote energy conservation and emission reduction (coal and water conservation, CO2 and NOx emission reduction) in the coal chemical industry and the large-scale utilization of carbon-based solid waste. Summary of the Invention

[0005] In view of this, the present invention provides a method for the synergistic coupling of hydrogen energy and coal chemical industry, which integrates new energy sources (wind and solar power generation) and secondary energy sources from coal chemical industry (low-carbon combustion power generation from carbon-based solid waste and waste heat power generation). This method can further promote the release of coal chemical industry capacity, achieve a leapfrog improvement in energy conservation and carbon reduction effects, elevate the level of resource utilization of carbon-based solid waste to a new stage, and significantly increase the utilization rate of new energy sources, thereby comprehensively enhancing the green transformation and development level of the coal chemical industry and providing a new, scalable, and replicable model for the coupled development of hydrogen energy and the coal chemical industry.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A multi-source synergistic coupling method for hydrogen energy and coal chemical industry based on carbon-based solid waste includes the following steps: (1) Carbon-rich products are obtained by separating carbon ash and dehydrating coal chemical carbon-based solid waste; (2) Further dehydrate and dry the carbon-rich product to make the moisture content ≤10% (the received basic calorific value is 2300kcal / kg) and then send it to the pump-back generator set for low-carbon combustion power generation. (3) Waste heat that cannot be directly utilized in coal chemical industry is recovered through heat exchange system and converted into high-quality steam with the ability to perform work, and then used to drive generator set to realize waste heat power generation. (4) Connect the new energy power generation and the power generation in steps (2) and (3) in parallel to form a multi-source coordinated island microgrid. Through intelligent regulation and scheduling, meet the power demand of the hydrogen electrolyzer, realize the coordination and control of multiple power sources in the island microgrid, and thus ensure the overall safe, stable and economical operation of the system. (5) The hydrogen produced in the hydrogen electrolyzer in step (4) is sent to the coal chemical system, thereby reducing the depth and load of CO conversion and significantly reducing CO2 emissions; (6) The oxygen generated in the hydrogen electrolyzer in step (4) is sent to a boiler or pulverized coal drying equipment for oxygen-enriched combustion to improve combustion efficiency and reduce NOx emissions.

[0007] The deep integration of hydrogen energy and the coal chemical industry is a key path to overcome the bottlenecks in the development of the coal chemical industry and promote its low-carbon transformation. Electricity price is a crucial factor affecting hydrogen production costs. This invention proposes using waste heat from coal chemical production and carbon-based solid waste combustion to maintain electrolyzers at a low load of 20%, avoiding frequent start-ups and shutdowns that could affect their lifespan. Further integration with new energy sources (wind and solar) creates an islanded microgrid, expanding hydrogen production capacity while keeping electricity prices low, producing hydrogen at costs close to those of ash hydrogen, and further integrating it with the coal chemical system. This invention coordinates multiple sources—new energy (wind and solar), secondary energy from coal chemical production (low-carbon combustion of carbon-based solid waste, waste heat utilization)—to form an islanded microgrid. Through intelligent regulation and scheduling, it achieves deep integration of the three major systems—microgrid, water electrolysis for hydrogen production, and dynamic control of coal chemical processes—solving a series of technical and economic issues related to the coupling of hydrogen energy and coal chemical industries, and integrating the development of modern coal chemical industry with green and low-carbon development.

[0008] Furthermore, the coal chemical carbon-based solid waste is fine slag from pulverized coal furnaces or coarse and fine slag from coal-water slurry furnaces.

[0009] Furthermore, the carbon-rich product has a dry basis carbon content of ≥28%, a moisture content of ≤35%, and an received basis calorific value of >1600 kcal / kg. Furthermore, the new energy source is wind power and / or solar power.

[0010] Furthermore, the scheme described in step (4) is as follows: when there is sufficient new energy power generation, the new energy power generation and the secondary energy power generation of coal chemical industry jointly maintain the electrolyzer at a wide load of 20% to 130%; when there is insufficient new energy power generation, the secondary energy power generation of coal chemical industry serves as a backup energy source to maintain the electrolyzer at a low load of 20%. Furthermore, it also includes step (7): utilizing the fly ash obtained after carbon ash separation and low-carbon combustion in steps (1) and (2) in a resource-based and ecological manner. Furthermore, the methods for resource and ecological utilization include: developing mine reinforcement materials, mine filling materials, functional soil remediation materials, or ecological restoration materials, which not only reduces the environmental pressure on enterprises to handle bulk solid waste, but also promotes the green and low-carbon development of the coal chemical industry.

[0011] The beneficial effects of this invention are as follows: This invention forms a multi-source collaborative islanded microgrid by combining new energy sources (wind and solar) with secondary energy from coal chemical industry (waste heat, carbon-based solid waste), thereby generating hydrogen from electricity. Currently, due to the intermittency and volatility of new energy sources, electrolyzers suffer severe degradation due to frequent start-ups and shutdowns. This necessitates either downloading electricity from the grid or adding energy storage or hydrogen storage power generation devices, resulting in high costs for hydrogen production through water electrolysis, severely limiting the large-scale commercial application of the water electrolysis hydrogen production industry. In this model, secondary energy from coal chemical industry serves as a backup energy source, maintaining the electrolyzer at a low load of 20%, thus avoiding the drawbacks of frequent start-ups and shutdowns that accelerate electrolyzer degradation when using new energy sources as intermittent energy sources, as well as the high costs associated with hydrogen production through primary energy sources such as water electrolysis, energy storage, or hydrogen power generation. By coupling hydrogen energy with coal chemical industry through this method, the phenomenon of "wind and solar curtailment" can be effectively alleviated, and the pain points of high carbon dioxide emissions and difficulty in resource utilization of carbon-based solid waste in the coal chemical industry can be addressed. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the multi-source synergistic coupling method of hydrogen energy and coal chemical industry based on carbon-based solid waste in Embodiment 1 of the present invention. Detailed Implementation

[0013] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] Example 1 A multi-source synergistic coupling method for hydrogen energy and coal chemical industry based on carbon-based solid waste includes the following steps: (1) Carbon-based solid wastes from coal chemical industry (fine slag from pulverized coal furnace, coarse and fine slag from coal-water slurry furnace, etc.) are separated by carbon ash and dehydrated to obtain carbon-rich products, so that the dry basis carbon content is ≥28% and the moisture (as received basis) is ≤35%, and the calorific value on the as received basis is >1600kcal / kg. (2) Further dehydrate and dry the carbon-rich product to make the moisture content (as received) ≤10% and the calorific value as received to about 2300 kcal / kg, and then send it to the pump-back generator set for low-carbon combustion power generation. (3) Waste heat that cannot be directly utilized in the coal chemical process is recovered through a heat exchange system and converted into steam to drive the generator set to realize waste heat power generation; (4) The wind and solar power generation and the power generation in steps (2) and (3) are connected in parallel to form a multi-source coordinated island microgrid. The power demand of the hydrogen electrolyzer is met through intelligent regulation and scheduling, realizing the coordination and control of multiple power sources in the island microgrid, thereby ensuring the overall safe, stable and economical operation of the system. When the new energy power generation is sufficient, the new energy power generation and the secondary energy power generation of coal chemical industry jointly maintain the electrolyzer at a wide load of 20% to 130%. When the new energy power generation is insufficient, the secondary energy power generation of coal chemical industry serves as a backup energy source to maintain the electrolyzer at a low load of 20%. (5) The hydrogen produced in the hydrogen electrolyzer in step (4) is sent to the coal chemical system, thereby reducing the depth and load of CO conversion; (6) The oxygen generated in the hydrogen electrolyzer in step (4) is sent to a boiler or pulverized coal drying equipment for oxygen-enriched combustion to improve combustion efficiency.

[0015] Based on the scheme of Example 1, the capacity of new energy configuration and the power generation capacity of isolated power plants are calculated using the waste heat resources and carbon-based solid waste resources of the Ningdong Energy Base. Coal chemical enterprises can use this method to match corresponding new energy sources, power plants, and electrolyzer capacities to implement a hydrogen energy and coal chemical coupling model. The specific calculation process is as follows: 1. Calculate the annual power generation potential of the enterprise's waste heat resources and carbon-based solid waste resources. Based on the scale of the coal chemical plant, the amount of waste heat resources can be calculated, the required generator set capacity can be determined, and the annual power generation A from the waste heat resources can be further calculated. Based on the amount of carbon-based solid waste resources (fine slag from pulverized coal furnaces, coarse slag from gasifiers, etc.) produced annually by coal chemical enterprises, and combined with the carbon content and moisture content of the carbon-based solid waste, the calorific value of the carbon-based solid waste can be calculated, and the required generator set and annual power generation B can be further calculated.

[0016] 2. Calculate the number of electrolytic cells required. The current comprehensive power consumption for producing hydrogen in an alkaline electrolyzer is 4.77 kWh / Nm³. 3 To measure this, the amount of hydrogen C that can be produced by the company's waste heat power generation and low-carbon combustion power generation was calculated.

[0017] With the current mainstream single-tank capacity of 1000Nm 3 Taking an electrolyzer with a capacity of 10 ...

[0018] According to the method of this invention, waste heat power generation and low-carbon combustion power generation maintain the electrolyzer at a low load of 20%. Under this mode, the annual hydrogen production of a single electrolyzer is 714 × 0.2 = 142.8 tons, so the number of electrolyzers required is N = C / 142.8.

[0019] 3. Calculate the installed capacity of new energy sources The maximum hydrogen production D when N electrolyzers are running at full capacity (8000 hours) can be calculated from the above. However, the annual comprehensive utilization time of wind and solar power in Ningdong area is about 2000 hours. Therefore, the amount of hydrogen that can be produced during the wind-solar coupling period is E=D×2000÷8000.

[0020] The known power consumption per unit of hydrogen is 4.77 kWh / Nm³. 3 By combining E, the required power generation of new energy sources can be calculated, and the installed capacity of new energy sources can be further calculated.

[0021] 4. Calculate the energy conservation and emission reduction benefits of coupling hydrogen energy with coal chemical industry. Under this model, the annual hydrogen production is C+E. With the original coal consumption remaining unchanged, each ton of hydrogen added to the coal chemical system can release 8 tons of methanol production capacity (this example uses methanol production from coal chemical syngas for calibration calculation, but it can also be calculated by replacing it with corresponding coal chemical products according to the actual situation of the enterprise), reduce CO2 emissions by 22 tons (if CO2 emissions from the low-carbon combustion of carbon-based solid waste are considered, then 8 tons of CO2 are emitted for every ton of hydrogen produced, so the project produces 1 ton of hydrogen and reduces CO2 emissions by 14 tons), and save 13.5 tons of water (currently, due to the high CO content and low H2 content in coal chemical syngas, the hydrogen-carbon ratio needs to be adjusted. If coal-to-hydrogen is used to supplement the H2 content, the water consumption per ton of hydrogen produced by coal is about 31 tons, and the water consumption per ton of hydrogen produced by electrolysis is about 17.5 tons). The generated oxygen is sent to a boiler or pulverized coal drying equipment for oxygen-enriched combustion, which improves combustion efficiency, reduces NOx emissions, and saves coal consumption. Combined with the standard coal consumption equivalent to the calorific value of carbon-based solid waste and the standard coal consumption equivalent to the methanol production capacity released, the total amount of coal saved can be calculated.

[0022] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A multi-source collaborative hydrogen energy and coal chemical coupling method based on carbon-based solid waste, characterized in that, It comprises the following steps: (1) Carbon ash separation and dehydration of coal chemical carbon-based solid waste to obtain carbon-rich products; (2) Further dehydration and drying of the carbon-rich products to obtain a product with a water content of ≤10%, and then sent to the back-pumping generator set for low-carbon combustion power generation; (3) The waste heat in the coal chemical industry that cannot be directly utilized is recovered through a heat exchange system, converted into steam, and used to drive the generator set to realize waste heat power generation; (4) The new energy power generation and the power generation of steps (2) and (3) are connected in parallel to form a multi-source collaborative island microgrid, which meets the electricity demand of the hydrogen production electrolyzer through intelligent control and scheduling, realizes the coordination and control of the island microgrid multi-power source, and realizes the coordination and control of the island microgrid multi-power source; (5) The hydrogen produced in the hydrogen production electrolyzer in step (4) is sent to the coal chemical system; (6) The oxygen produced in the hydrogen production electrolyzer in step (4) is sent to the boiler or coal powder drying equipment for oxygen-enriched combustion.

2. The method according to claim 1, wherein the method is characterized in that, The coal chemical carbon-based solid waste is fine slag of a pulverized coal furnace or coarse and fine slag of a coal water slurry furnace.

3. The method according to claim 1 or 2, characterized in that, The carbon-rich product has a dry basis carbon content of ≥28%, a moisture content of ≤35%, and a received basis calorific value of >1600kcal / kg.

4. The method according to claim 1, wherein the method is characterized in that, The new energy is wind power generation and / or light power generation.

5. The method according to claim 1, wherein the method is characterized in that, In step (4), the scheme is that when the new energy power generation is sufficient, the new energy power generation and the coal chemical secondary energy power generation jointly maintain the 20%-130% wide load operation of the electrolyzer; when the new energy power generation is insufficient, the coal chemical secondary energy power generation serves as the bottom-up energy to maintain the 20% low load operation of the electrolyzer.

6. The method according to claim 1, wherein the method is characterized in that, It also comprises step (7): resource and ecological utilization of fly ash obtained after carbon ash separation and low-carbon combustion in steps (1) and (2).

7. The method according to claim 6, wherein the method is characterized in that, The resource and ecological utilization method comprises developing mine reinforcement materials, mine filling materials, functional soil remediation materials, or ecological remediation materials.

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