Method for optimizing comprehensive energy system of thermal power generating unit

Abstract

The invention discloses a thermal power generating unit comprehensive energy system optimization method, which comprises the following steps: constructing a thermal power generating unit coal ammonia co-combustion model, and analyzing the ammonia-doped combustion low-carbon emission characteristic of a thermal power generating unit; mechanism analysis and model construction are carried out on the hydrogen energy utilization unit, and a comprehensive energy system optimization scheduling strategy considering multi-energy flow is analyzed; based on the coal ammonia co-combustion model and the hydrogen energy utilization unit model, a stepped carbon transaction cost model is constructed according to a datum line method, and system low-carbon economic constraints are formed; the coal consumption cost, the gas purchasing and wind and light abandoning cost and the carbon transaction cost are integrated, operation constraints of all the units are combined, and a low-carbon economic dispatching model of the comprehensive energy system is established; solving the scheduling model in the step 4 through Gurobi, and outputting the optimal operation parameters of each unit; and establishing a low-carbon economic dispatching model of the comprehensive energy system, and analyzing and verifying the effectiveness of improving the running economy and the energy consumption cleanliness of the comprehensive energy system by the provided optimal dispatching method through setting a plurality of running schemes.

Description

Technical Field

[0001] This invention relates to the field of energy technology, and in particular to a method for optimizing the integrated energy system of a thermal power unit. Background Technology

[0002] To achieve the goals of "carbon peaking and carbon neutrality," my country's energy structure urgently needs to transform towards a clean, low-carbon, and sustainable direction. As of 2024, new energy installed capacity accounted for 39.12% of my country's total installed capacity and 21.41% of its electricity generation. However, the growth of large-scale wind and solar power units is accompanied by strong uncertainties and randomness, resulting in the system still heavily relying on fossil fuels and low efficiency in the utilization of clean energy. Therefore, how to efficiently utilize new energy sources to promote the low-carbon transformation of the energy structure and facilitate a high proportion of wind and solar power consumption is of great significance.

[0003] The multi-energy flow and multi-energy coupling characteristics of integrated energy systems can adapt to the large-scale integration of new energy sources, thereby enhancing the absorption capacity of wind and solar power. Hydrogen energy, as a clean secondary energy source, has diverse applications and the advantage of zero carbon emissions. Ammonia-blended combustion in thermal power units can effectively reduce coal consumption and support low-carbon emissions. Therefore, it is urgent to conduct research on the optimized scheduling of integrated energy systems combining ammonia-blended combustion in thermal power units and hydrogen energy utilization, and to rationally utilize low-carbon resources to guide the system towards a cleaner and lower-carbon transformation.

[0004] Domestic and international scholars have conducted extensive research on the optimal scheduling of integrated energy systems utilizing hydrogen energy. However, the following issues still need to be addressed: 1. While the focus is primarily on improving the system's renewable energy absorption rate using hydrogen energy, the potential value of multi-mode coordinated operation in hybrid combustion, such as hydrogen-to-ammonia production, hydrogen participation in gas turbine units, and ammonia-blended combustion in thermal power units, remains to be explored, and the resulting carbon emission reduction impact has received relatively little attention; 2. The support of carbon trading mechanisms for ammonia-blended combustion in thermal power units has not been thoroughly explored, and the impact of carbon trading mechanisms has not been fully quantified. Therefore, it is essential to design an integrated energy system optimization method that considers both ammonia-blended combustion in thermal power units and hydrogen energy utilization. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this invention is: the potential value of multi-mode coordinated operation of thermal power units, such as ammonia-blended combustion, has not been explored.

[0006] The above-mentioned technical problems are solved by the following technical solution: This invention proposes an optimization method for the integrated energy system of thermal power units, including constructing a coal-ammonia co-combustion model of thermal power units and analyzing the low-carbon emission characteristics of ammonia-blended combustion in thermal power units; Mechanism analysis and model building of hydrogen energy utilization units were carried out, and optimization scheduling strategies for integrated energy systems that take into account multi-energy flow were analyzed. Based on the coal-ammonia co-combustion model and the hydrogen energy utilization unit model, a tiered carbon trading cost model is constructed using the baseline method to form a systemic low-carbon economic constraint. By integrating coal consumption costs, gas purchase and wind / solar curtailment costs, and carbon trading costs, and taking into account the operational constraints of each unit, a low-carbon economic dispatch model for the integrated energy system is established. The scheduling model in step 4 is solved using Gurobi, and the optimal operating parameters for each unit are output.

[0007] In a preferred embodiment of the integrated energy system optimization method for thermal power units described in this invention: the construction of a coal-ammonia co-combustion model for thermal power units and the analysis of the low-carbon emission characteristics of ammonia-blended combustion in thermal power units specifically involves: Co-combustion of ammonia and coal in thermal power units can effectively achieve clean energy utilization of the units; In the formula, , , These are the coal consumption coefficients for thermal power units; This refers to the output power of the thermal power unit. This refers to the coal consumption of thermal power units after ammonia blending. This refers to the ammonia consumption of thermal power units. and These are the net calorific values ​​of ammonia and coal, respectively. Carbon emissions are absorbed by installing carbon capture devices. The energy consumption of carbon capture devices includes stationary energy consumption and operational energy consumption. The operational energy consumption mainly depends on the amount of carbon emissions absorbed by the carbon capture device, as shown in the model below: In the formula, and These are the carbon emissions and carbon emission coefficient of thermal power units, respectively. This refers to the flue gas split ratio of the thermal power unit. For carbon capture efficiency; The amount of carbon dioxide to be captured supplied to the solution storage device; To capture the total amount of carbon dioxide; Energy consumption to capture a unit mass of carbon dioxide; and These are the operating and stationary energy consumption of the carbon capture device, respectively. This refers to the net output power of the thermal power unit.

[0008] In a preferred embodiment of the integrated energy system optimization method for thermal power units described in this invention: the hydrogen energy utilization unit includes an electrolyzer, a hydrogen storage tank, a hydrogen fuel cell, a methane reactor, and an ammonia production device.

[0009] In a preferred embodiment of the integrated energy system optimization method for thermal power units according to the present invention: the integrated energy system optimization scheduling strategy considering multi-energy flow includes constructing an electrolyzer model; the electrolyzer model is specifically: The specific model of the electrolytic cell is as follows: In the formula, and These are the electrical energy input and hydrogen energy output of the electrolyzer, respectively. and These are the upper and lower limits of the electrical energy input to the electrolytic cell, respectively. and These represent the upper and lower limits of the electrolytic cell's power input ramp-up.

[0010] The analysis of integrated energy system optimization scheduling strategies that take into account multi-energy flow includes constructing an ammonia production unit model; the ammonia production unit model is specifically as follows: In the formula, and These are the hydrogen input and ammonia output of the ammonia production equipment, respectively. For ammonia production efficiency; The heat release ratio for ammonia production equipment; The mass of ammonia produced by the ammonia production equipment; The heat power released to produce a unit mass of ammonia gas; The thermal power provided to the ammonia production equipment; and The upper and lower limits for hydrogen input to the ammonia production equipment; and The upper and lower limits for hydrogen input ramp-up in the ammonia production equipment.

[0011] In a preferred embodiment of the integrated energy system optimization method for thermal power units described in this invention: the analysis of integrated energy system optimization scheduling strategies considering multi-energy flow includes constructing a hydrogen storage tank model; the hydrogen storage tank model is specifically: In the formula, This refers to the remaining hydrogen quantity in the hydrogen storage tank. This is the loss coefficient for the hydrogen storage tank; and These are the hydrogen filling power and hydrogen discharging power of the hydrogen storage tank, respectively. and Hydrogen storage tank filling and discharging efficiency; and These are binary variables, representing the hydrogen charging and discharging states of the hydrogen storage tank, respectively. and These are the maximum operating power for charging and discharging hydrogen from the hydrogen storage tank; and These represent the hydrogen storage capacity of the hydrogen storage tank at the beginning and end of the respective periods. and These represent the upper and lower limits of hydrogen storage capacity in the hydrogen storage tank.

[0012] In a preferred embodiment of the integrated energy system optimization method for thermal power units described in this invention: the analysis and consideration of multi-energy flow integrated energy system optimization scheduling strategy includes constructing an ammonia production unit model; the ammonia production unit model specifically comprises: In the formula, and These are the hydrogen input and ammonia output of the ammonia production equipment, respectively. For ammonia production efficiency; The heat release ratio for ammonia production equipment; The mass of ammonia produced by the ammonia production equipment; The heat power released to produce a unit mass of ammonia gas; The thermal power provided to the ammonia production equipment; and The upper and lower limits for hydrogen input to the ammonia production equipment; and The upper and lower limits for hydrogen input ramp-up in the ammonia production equipment.

[0013] In a preferred embodiment of the integrated energy system optimization method for thermal power units according to the present invention: the analysis of the integrated energy system optimization scheduling strategy considering multi-energy flow includes constructing a gas turbine unit model; the gas turbine unit model is specifically: In the formula, The energy input power of the gas turbine unit; and The inputs for the gas turbine unit are hydrogen and natural gas, respectively. and For the electrical and thermal energy output of the gas turbine; and These refer to the energy conversion efficiency of gas turbines and gas turbine units, respectively. and These are the upper and lower limits of the z-input power of the gas turbine unit, respectively. and These are the upper and lower limits of the input power ramp-up for the gas turbine unit; and These are the upper and lower limits of the gas turbine's thermoelectric output ratio.

[0014] In a preferred embodiment of the integrated energy system optimization method for thermal power units described in this invention: the integrated energy system optimization scheduling strategy considering multi-energy flow includes a methane reactor model; the methane reactor model is specifically: In the formula, and These are the hydrogen input and natural gas output of the methane reactor, respectively. To improve the efficiency of natural gas production; The proportion of heat released by the methane reactor; The heat output is generated per unit of natural gas; The thermal power provided to the methane reactor; The amount of carbon dioxide consumed by the methane reactor; and The upper and lower limits for hydrogen input to the ammonia production equipment; and The upper and lower limits for hydrogen input ramp-up in the ammonia production equipment.

[0015] In a preferred embodiment of the integrated energy system optimization method for thermal power units described in this invention: in the step-based carbon trading cost model constructed using the baseline method, the carbon trading cost is calculated as follows: In the formula, The base price for carbon trading. The quota for participating in carbon market trading; the percentage increase in carbon trading prices. This represents the range for carbon trading price increases.

[0016] In a preferred embodiment of the integrated energy system optimization method for thermal power units described in this invention: the integration of coal consumption costs, gas purchase and wind / solar curtailment costs, and carbon trading costs, combined with the operational constraints of each unit, to establish a low-carbon economic dispatch model for the integrated energy system specifically involves: using the unit coal consumption cost... Gas purchase cost Equipment operation and maintenance costs Cost of curtailed renewable energy Carbon trading costs And carbon capture integration cost sum The target is the minimum, and the specific calculation method is as follows: In the formula, T represents the total scheduling period; Price per unit weight of coal; For wind power unit operation and maintenance costs; The unit operation and maintenance cost of photovoltaic power generation; The unit operation and maintenance cost of the electrolytic cell; The unit operation and maintenance cost of a methane reactor; The unit operation and maintenance cost of the ammonia production unit; The unit operation and maintenance cost of the gas turbine; Unit operation and maintenance cost of gas-fired boilers; Unit operation and maintenance cost of hydrogen storage tanks; For natural gas, the time-of-use price is [price]. Cost per unit power of wind and solar power curtailment; Cost of solution loss; This refers to the daily depreciation cost of the carbon capture device. Costs associated with carbon dioxide storage and transportation; This represents the cost coefficient for amine solutions. This is the solution running loss coefficient; This refers to the volume of alkanolamine solution required for the solution storage within the carbon capture device. The unit cost coefficient for transporting and storing carbon dioxide; The discount rate for carbon capture projects; The total cost per unit volume of solution storage; and These represent the total cost of the solution storage device.

[0017] The beneficial effects of this invention are: establishing a low-carbon economic dispatch model for integrated energy systems, and analyzing and verifying the effectiveness of the proposed optimization dispatch method in improving the economic efficiency and clean energy use of integrated energy systems by setting multiple operating schemes. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 A schematic diagram of the integrated energy system operation framework is shown; Figure 2 A schematic diagram of the multi-energy load demand of the integrated energy system is shown; Figure 3 A schematic diagram showing the wind power and photovoltaic output forecast information of the integrated energy system is provided. Figure 4 The diagram illustrates the results of multi-energy dispatching of the integrated energy system under different schemes. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0021] This embodiment provides a method for optimizing the integrated energy system of a thermal power unit, including: Step 1: Construct a coal-ammonia co-combustion model for thermal power units and analyze the low-carbon emission characteristics of ammonia-infused combustion in thermal power units; considering ammonia-infused combustion in thermal power units, construct a coal-ammonia co-combustion model for thermal power units and analyze the low-carbon emission characteristics of ammonia-infused combustion in thermal power units.

[0022] Specifically, considering ammonia-blended combustion in thermal power units, a coal-ammonia co-combustion model for thermal power units is constructed to analyze the low-carbon emission characteristics of ammonia-blended combustion in thermal power units. Traditional thermal power units are heavily polluting, making it difficult to guarantee clean energy utilization and low-carbon operation. Ammonia has clean and low-carbon operating characteristics; by co-combusting ammonia with coal in thermal power units, clean energy utilization can be effectively achieved.

[0023] (1) In the formula, , , These are the coal consumption coefficients for thermal power units; This refers to the output power of the thermal power unit. This refers to the coal consumption of thermal power units after ammonia blending. This refers to the ammonia consumption of thermal power units. and These are the net calorific values ​​of ammonia and coal, respectively.

[0024] In addition to reducing carbon emissions through coal-ammonia co-firing, thermal power units can also absorb carbon emissions by installing carbon capture devices. The energy consumption of carbon capture devices includes stationary energy consumption and operational energy consumption. Operational energy consumption mainly depends on the amount of carbon emissions absorbed by the carbon capture device, as shown in the model below. (2) In the formula, and These are the carbon emissions and carbon emission coefficient of thermal power units, respectively. This refers to the flue gas split ratio of the thermal power unit. For carbon capture efficiency; The amount of carbon dioxide to be captured supplied to the solution storage device; To capture the total amount of carbon dioxide; Energy consumption to capture a unit mass of carbon dioxide; and These are the operating and stationary energy consumption of the carbon capture device, respectively. This refers to the net output power of the thermal power unit.

[0025] Step 2: Conduct mechanism analysis and model building for hydrogen energy utilization units, and analyze the comprehensive energy system optimization scheduling strategy that takes into account multi-energy flow; Mechanism analysis and model building are conducted for hydrogen energy utilization units consisting of electrolyzers, hydrogen storage tanks, hydrogen fuel cells, methane reactors, and ammonia production units. Optimization scheduling strategies for integrated energy systems considering multi-energy flows are analyzed, specifically: The electrolyzer utilizes water resources and surplus electricity from the source side, and the hydrogen produced from water electrolysis sustains the operation of the hydrogen-consuming units. The specific model of the electrolyzer is shown below: (3) In the formula, and These are the electrical energy input and hydrogen energy output of the electrolyzer, respectively. and These are the upper and lower limits of the electrical energy input to the electrolytic cell, respectively. and These are the upper and lower limits of the electrolytic cell's power input ramp-up. The hydrogen storage tank serves as a bridge between hydrogen production and consumption in the system, and its model is shown below: (4) In the formula, This refers to the remaining hydrogen quantity in the hydrogen storage tank. This is the loss coefficient for the hydrogen storage tank; and These are the hydrogen filling power and hydrogen discharging power of the hydrogen storage tank, respectively. and Hydrogen storage tank filling and discharging efficiency; and These are binary variables, representing the hydrogen charging and discharging states of the hydrogen storage tank, respectively. and These are the maximum operating power for charging and discharging hydrogen from the hydrogen storage tank; and These represent the hydrogen storage capacity of the hydrogen storage tank at the beginning and end of the respective periods. and These represent the upper and lower limits of hydrogen storage capacity in the hydrogen storage tank.

[0026] The ammonia production unit mainly consists of a pressure swing adsorption (PSA) unit and an ammonia synthesis unit. The PSA unit uses air as feedstock to generate nitrogen. The ammonia synthesis unit uses hydrogen and nitrogen as feedstock to synthesize ammonia through the Harper reaction. Since ammonia production is an exothermic chemical reaction, considering energy cascade utilization, the model is as follows: (5) In the formula, and These are the hydrogen input and ammonia output of the ammonia production equipment, respectively. For ammonia production efficiency; The heat release ratio for ammonia production equipment; The mass of ammonia produced by the ammonia production equipment; The heat power released to produce a unit mass of ammonia gas; The thermal power provided to the ammonia production equipment; and The upper and lower limits for hydrogen input to the ammonia production equipment; and The upper and lower limits for hydrogen input ramp-up in the ammonia production equipment.

[0027] Gas turbine units mainly consist of a gas turbine and a gas boiler. Traditional gas turbine units primarily use natural gas as fuel, resulting in significant carbon dioxide emissions during operation. Related research indicates that gas turbine units can co-fire some hydrogen with natural gas, limiting the hydrogen co-firing ratio to within 20%, thereby improving the unit's clean energy utilization while reducing carbon emissions.

[0028] (6) In the formula, The energy input power of the gas turbine unit; and The inputs for the gas turbine unit are hydrogen and natural gas, respectively. and For the electrical and thermal energy output of the gas turbine; and These refer to the energy conversion efficiency of gas turbines and gas turbine units, respectively. and These are the upper and lower limits of the z-input power of the gas turbine unit, respectively. and These are the upper and lower limits of the input power ramp-up for the gas turbine unit; and These represent the upper and lower limits of the hot spot output ratio of the gas turbine.

[0029] The methane reactor uses hydrogen and carbon dioxide as feedstock to produce natural gas, similar to an ammonia production reaction. The production of natural gas in the methane reactor releases a certain amount of heat energy. A specific model is shown below: (7) In the formula, and These are the hydrogen input and natural gas output of the methane reactor, respectively. To improve the efficiency of natural gas production; The proportion of heat released by the methane reactor; The heat output is generated per unit of natural gas; The thermal power provided to the methane reactor; The amount of carbon dioxide consumed by the methane reactor; and The upper and lower limits for hydrogen input to the ammonia production equipment; and The upper and lower limits for hydrogen input ramp-up in the ammonia production equipment.

[0030] In summary, integrated energy systems that aggregate multiple energy flows can better leverage the clean characteristics of new energy sources and constrain carbon emissions. On one hand, regarding the balance of supply and demand for multiple energy sources, electrolyzers respond to large-scale new energy power generation on the source side, producing hydrogen to supply ammonia production units and gas turbine units, realizing the conversion of heterogeneous energy sources such as electricity-hydrogen-gas-heat-ammonia, ensuring the consumption of surplus electricity and supplying the demand of multiple energy loads. At the same time, excess hydrogen is stored in hydrogen storage tanks, achieving smooth regulation of hydrogen production and consumption and expanding the space for new energy consumption. On the other hand, hydrogen-using equipment, mainly methane reactors and ammonia production units, absorbs hydrogen for the production of natural gas and ammonia. Ammonia can replace part of the coal in the combustion of thermal power units, reducing the coal consumption of the units. Gas turbine units can adopt hydrogen-blended combustion, reducing the use of natural gas, achieving cleaner fuel for the units, and reducing the carbon emissions of the units.

[0031] Step 3: Based on the coal-ammonia co-combustion model and the hydrogen energy utilization unit model, construct a tiered carbon trading cost model using the baseline method to form a systemic low-carbon economic constraint. Construct a carbon trading cost model under a tiered carbon trading mechanism, specifically as follows: Regarding market trading mechanisms, to reduce the excessive use of fossil fuels, my country has established legal carbon emission rights, allowing systems to participate in carbon emission trading in the market, using economic incentives to promote energy conservation and emission reduction. Firstly, the government allocates free carbon emission allowances to carbon emission sources. Systems can trade surplus allowances in the market based on their actual carbon emissions to obtain some revenue. However, for fossil fuel units whose actual carbon emissions exceed their carbon emission allowances, the system must purchase corresponding carbon emission allowances from the market to meet its carbon emission needs. The tiered carbon trading mechanism model mainly includes a carbon emission allowance model, an actual carbon emission model, and the tiered carbon trading mechanism itself.

[0032] The actual carbon emission sources of integrated energy systems utilizing hydrogen energy and thermal power units mainly include thermal power units, gas turbines, and gas turbine units. Currently, my country primarily uses the baseline method to allocate carbon emission quotas, considering only carbon emissions during the unit operation phase. The carbon emission quotas for each unit are shown below: (8) In the formula, , and These are carbon emission quotas for thermal power units, gas turbines, and gas-fired boilers, respectively. and These are carbon emission quotas for power supply and heating units, respectively; This is the electro-thermal conversion factor.

[0033] Since most of the carbon dioxide emissions from thermal power units are captured by carbon capture devices, the actual carbon emissions from thermal power units are as follows: (9) Carbon emissions from gas turbines and gas-fired boilers can be expressed as: (10) In the formula, and These are the actual carbon emissions from gas turbines and gas-fired boilers, respectively. To absorb the carbon dioxide released per unit of natural gas.

[0034] In summary, the difference between the actual carbon emissions of the integrated energy system and the carbon emission allowance yields the allowance for participating in carbon market trading. As shown below: (11) Accordingly, the carbon trading costs are as follows: (12) In the formula, This is the base price for carbon trading.

[0035] However, due to the insufficient capacity of traditional carbon trading mechanisms to restrict high-carbon-emission units, a tiered carbon trading mechanism is introduced. This mechanism uses progressively increasing carbon trading prices to constrain units to use cleaner fuels instead of fossil fuels, thereby reducing carbon emissions. Therefore, equation (12) is modified as follows: (13) In the formula, represents the percentage increase in carbon trading prices; This represents the range for carbon trading price increases.

[0036] Step 4: Integrate coal consumption costs, gas purchase and wind / solar curtailment costs, and carbon trading costs, and combine these with the operational constraints of each unit to establish a comprehensive low-carbon economic dispatch model for the energy system. A low-carbon economic dispatch model for the integrated energy system is established with the goal of minimizing the sum of operating costs, including coal consumption, gas purchase, and wind and solar curtailment, in order to optimize the economic efficiency of the integrated energy system. Specifically: The optimization goal of the integrated energy system takes into account both economic benefits and environmental protection, with the unit's coal consumption cost as the primary consideration. Gas purchase cost Equipment operation and maintenance costs Cost of curtailed renewable energy Carbon trading costs And carbon capture integration cost sum Minimum is the target.

[0037] (14) (15) (16) (17) (18) (19) (20) (twenty one) (twenty two) In the formula, T represents the total scheduling period; Price per unit weight of coal; For wind power unit operation and maintenance costs; The unit operation and maintenance cost of photovoltaic power generation; The unit operation and maintenance cost of the electrolytic cell; The unit operation and maintenance cost of a methane reactor; The unit operation and maintenance cost of the ammonia production unit; The unit operation and maintenance cost of the gas turbine; Unit operation and maintenance cost of gas-fired boilers; Unit operation and maintenance cost of hydrogen storage tanks; For natural gas, the time-of-use price is [price]. Cost per unit power of wind and solar power curtailment; Cost of solution loss; This refers to the daily depreciation cost of the carbon capture device. Costs associated with carbon dioxide storage and transportation; This represents the cost coefficient for amine solutions. This is the solution running loss coefficient; This refers to the volume of alkanolamine solution required for the solution storage within the carbon capture device. The unit cost coefficient for transporting and storing carbon dioxide; The discount rate for carbon capture projects; The total cost per unit volume of solution storage; and These represent the total cost of the solution storage device.

[0038] The constraints of the integrated energy system mainly include power balance constraints, operating constraints of thermal power units with ammonia-blended combustion, equipment operating constraints, wind power and photovoltaic power output constraints, and gas supply constraints. Among them, the power balance constraints are: (twenty three) (twenty four) (25) (26) In the formula, , These are the day-ahead dispatch power for wind power and solar power, respectively. The amount of gas purchased from gas sources for the integrated energy system; , , These are the electrical load, heat load, and gas load of the integrated energy system.

[0039] Operating constraints of thermal power units with ammonia-blended combustion: (27) In the formula, and These are the upper and lower limits of the electrical energy output power of thermal power units. and These are the upper and lower limits for the ramp-up of the electrical output power of thermal power units.

[0040] When ammonia is added to the combustion chamber of a thermal power unit, it has a certain impact on the combustion conditions. To ensure stable operation of the unit, the ammonia addition ratio needs to be adjusted. Restrictions should be imposed.

[0041] (28) In addition to limiting the ammonia blending ratio in the unit, carbon capture devices equipped with solution storage units must also meet the following constraints: (29) (30) In the formula, This refers to the volume of alkanolamine solution required for the solution storage within the carbon capture device. and These are the molar masses of alkanolamine and carbon dioxide, respectively. This refers to the output of the regeneration tower within the carbon capture device. and These represent the concentration and density of the alkanolamine solution, respectively. and These are the maximum capacities of the rich and lean electrolyte storage devices, respectively. and These are the capacities of the rich and lean solution storage containers, respectively. and The capacity of the flooded storage tank at the beginning and end of the period; and This represents the initial and final capacity of the depleted fluid storage device.

[0042] The equipment operating constraints are: Operating constraints for equipment such as electrolyzers, gas turbines, gas boilers, methane reactors, and ammonia production units (see formulas (1)-(5) for details).

[0043] Wind power and solar power output constraints: (31) In the formula, , Forecast power output for wind and solar power; , The power output of wind and solar power has been reduced recently.

[0044] Gas supply constraints: Because the natural gas production method in an integrated energy system is singular, it needs to be linked to a gas source to meet the internal gas energy supply and demand balance. However, considering the pressure of the gas pipeline, the gas source supply model needs to be restricted, as shown below: (32) In the formula, and These are the upper and lower limits of the gas supply volume; and These are limits on fluctuations in the gas supply volume.

[0045] Step 5: Solve the scheduling model from Step 4 using Gurobi and output the optimal operating parameters for each unit.

[0046] The low-carbon economic dispatch model of the integrated energy system is solved using the commercially efficient solver Gurobi, specifically as follows: This invention provides an embodiment to verify the economic, clean, and low-carbon benefits of the optimized scheduling method described herein, in order to Figure 1 The integrated energy system operation framework shown is used as the test object, with a 24-hour scheduling cycle. A case study is conducted based on an improved IEEE 39-node system. Multi-energy load demand and predicted wind and solar power output are as follows: Figure 2-3 As shown. Carbon emission quota per unit of electricity supplied by the generating unit. 0.728 kg / kW·h, unit heating carbon emission quota 0.3 kg / kW·h; carbon dioxide released per unit of coal consumed 2.57 kg / t, carbon dioxide released per unit of methane consumed 0.324 kg / kW·h, natural gas unit price is taken as 3.0 yuan / m³, unit reduction of new energy penalty cost =150 yuan / MW·h.

[0047] To verify the effectiveness of the optimized scheduling method proposed in this invention, the following five scheduling schemes were compared and analyzed. Option 1 does not consider the hydrogen production-storage-diversified utilization process and carbon market trading in the integrated energy system; Option 2 introduces a hydrogen energy utilization model based on Option 1, incorporating an electrolyzer, hydrogen storage tank, and methane reactor. Option 3 introduces ammonia production unit and unit co-firing technology based on Option 2; Option 4, based on Option 3, considers the recovery of waste heat from the ammonia production-gas process to participate in the heat energy supply. Option 5, based on Option 4, introduces a tiered transaction mechanism, which is the optimized scheduling scheme proposed in this invention. The costs and results under different optimization schemes are shown in Table 1.

[0048] Table 1. Optimization results of integrated energy system under different schemes

[0049] As shown in Table 1, compared to Scheme 1, Scheme 2 reduces the cost of renewable energy curtailment and coal consumption by RMB 516,000 and RMB 284,000, respectively. Although the introduction of hydrogen energy utilization in Scheme 2 increases equipment operation and maintenance costs by RMB 134,000, the total operating cost of the integrated energy system still decreases by 8.43%. This demonstrates that the introduction of hydrogen production-storage-methanation processes balances renewable energy consumption and low-carbon benefits in the integrated energy system. Compared to Scheme 2, Scheme 3 introduces an ammonia production unit and unit co-combustion technology. Zero-carbon energy sources hydrogen and ammonia participate in the co-combustion of gas turbines and thermal power units, respectively, replacing some fossil fuels. The gas purchase cost and coal consumption cost of the integrated energy system decrease by 10.47% and 4.72%, respectively, with a corresponding reduction in carbon emissions of 9.24%. Furthermore, the increased use of hydrogen energy further expands the space for renewable energy consumption, reducing the cost of curtailment by RMB 33,000. Compared to Option 3, Option 4, targeting the methane and ammonia production stages, recovers waste heat from the reactions to supply heat load, improving energy efficiency and increasing the heating flexibility of the integrated energy system. This alleviates the heating pressure on gas turbines and gas boilers, and reduces gas purchase costs by 55,000 yuan. In contrast to Option 4, Option 5 adopts a tiered carbon trading mechanism, making carbon-emitting units more inclined to use carbon-free hydrogen and ammonia for co-combustion, reducing carbon emissions. This reduces the cost of renewable energy curtailment in the integrated energy system by 8,000 yuan, resulting in a total cost reduction of 189,000 yuan.

[0050] In summary, with the improvement of the operation plan, all operating costs except equipment maintenance costs have been significantly reduced, the level of new energy consumption has increased, and carbon emissions have decreased, proving that the proposed scheduling plan has good economic and environmental benefits.

[0051] To further clarify the role of expanding hydrogen energy utilization and waste heat absorption in Scheme 5, the scheduling results of Schemes 1 and 5 are analyzed as examples. The scheduling results of electricity-heat-gas energy in Schemes 1 and 5 are as follows: Figure 3 As shown.

[0052] Depend on Figure 3 It is evident that Scheme 5, compared to Scheme 1, further considers multiple hydrogen energy utilization methods, combining electrolyzers and hydrogen storage tanks to form a comprehensive hydrogen energy scheduling system encompassing water electrolysis for hydrogen production, hydrogen storage in hydrogen storage tanks, and hydrogen consumption via ammonia production, methane production, and co-firing. During peak wind power periods at night (1:00-5:00 and 20:00-24:00), surplus renewable energy from the source side is utilized through water electrolysis for hydrogen production, increasing the renewable energy grid connection capacity by 3849.68MW, approximately 29.67%. Hydrogen production has multiple applications, including methanation, ammonia production, and co-firing with generating units, all of which reduce fossil fuel consumption in the integrated energy system, resulting in lower coal consumption and gas purchase costs, thus achieving economical dispatch.

[0053] To address the balance of heat supply and demand in the integrated energy system across different time periods, Scheme 5 introduces a waste heat recovery device to recover the heat released by the ammonia production unit and methane reactor during the ammonia and methane synthesis processes. This recovers some of the heat load demand, reduces the heating pressure on the gas turbine units, and improves the heating flexibility of the integrated energy system. Furthermore, the heat absorption period coincides primarily with peak wind power generation times, further demonstrating the effectiveness of broadening hydrogen energy utilization methods to promote the consumption of new energy sources.

[0054] To address the balance of gas supply and demand in the integrated energy system across different time periods, Scheme 5 introduces co-firing technology for gas turbine units. This allows gas turbine units to partially replace natural gas combustion with hydrogen, reducing the utilization of fossil fuels. Taking a gas-fired boiler as an example, compared to Scheme 1, the heat output of the gas-fired boiler in Scheme 5 changes from 7622.28MW to 6392.02MW, a decrease of approximately 16.14%. However, the gas consumption of the unit abruptly changes from 975.34m³ to 687.04m³, a decrease of approximately 29.55%, effectively demonstrating the effectiveness of introducing co-firing technology in reducing the integrated energy system's dependence on gas sources.

[0055] To verify the effectiveness of the proposed tiered carbon trading mechanism for clean energy utilization and low carbon emissions in integrated energy systems, three operational schemes were compared and analyzed. Scheme 6 is a conventional economic dispatch scheme under the tiered carbon trading mechanism, which does not consider carbon trading costs but only the costs of coal consumption, gas purchase, and abandoned electricity. Scheme 7 is an economic dispatch scheme for integrated energy systems under a fixed carbon price trading mechanism. Scheme 8 is an economic dispatch scheme for integrated energy systems under the tiered carbon price trading mechanism (i.e., Scheme 5). Table 2 shows the dispatch results for different carbon trading mechanisms.

[0056] Table 2. Scheduling Results of Different Carbon Trading Mechanisms

[0057] As shown in the table, the carbon emissions of the scheduling schemes that include carbon trading are significantly lower than those that do not. Specifically, Scheme 7 reduces carbon emissions by 2.17% compared to Scheme 6, and Scheme 8 reduces carbon emissions by 2.76%. Furthermore, Scheme 8 reduces carbon emissions by 23 tons compared to Scheme 7. This demonstrates that tiered carbon trading can maximize carbon emission control and achieve energy conservation and emission reduction in the integrated energy system. The main reason is that the integrated energy system aims to minimize total operating costs. Scheme 6, which does not include carbon trading costs, does not require trading carbon emission allowances in the carbon market, thus failing to constrain carbon-emitting units and resulting in the highest coal consumption and natural gas demand, leading to the highest carbon emissions under Scheme 6. Although Scheme 7's optimization objective includes carbon trading costs, under the constraint of a fixed carbon price trading mechanism, the impact of carbon trading costs on carbon-emitting units is minimal; coal consumption costs and natural gas purchase costs only decrease by 0.24% and 0.02%, respectively. Option 8, on the other hand, sees carbon prices rise as the number of tradable carbon emission allowances increases. At the same time, with the help of co-firing technology, the fossil energy required by carbon emission units is reduced, and the number of sellable carbon emission allowances increases while the output remains the same, which can bring better economic benefits to the integrated energy system.

[0058] The present invention provides an integrated energy system optimization method that considers ammonia-blended combustion and hydrogen energy utilization in thermal power units. First, it considers ammonia participation in the combustion of thermal power units and constructs a coal-ammonia co-combustion model. Second, it conducts mechanism analysis and model construction for hydrogen energy utilization units composed of electrolyzers, hydrogen storage tanks, hydrogen fuel cells, methane reactors, and ammonia production devices, and analyzes the integrated energy system scheduling strategy considering multi-energy flow. Then, it constructs a carbon trading cost model under a tiered carbon trading mechanism to guide energy conservation and emission reduction in the integrated energy system. Finally, with the goal of minimizing the sum of operating costs such as coal consumption, gas purchase, and wind and solar curtailment, it establishes a low-carbon economic scheduling model for the integrated energy system. By setting multiple operating schemes, it analyzes and verifies the effectiveness of the proposed optimization scheduling method in improving the economic efficiency and clean energy use of the integrated energy system.

[0059] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A method for optimizing the integrated energy system of a thermal power unit, characterized in that: The application relates to a low-carbon economic dispatching method for a comprehensive energy system. A coal-ammonia mixed combustion model of a thermal power unit is constructed to analyze low-carbon emission characteristics of the thermal power unit in ammonia mixed combustion; A mechanism analysis and model construction are performed on a hydrogen energy utilization unit, and an optimal dispatching strategy of a comprehensive energy system considering multi-energy flow is analyzed; Based on the coal-ammonia mixed combustion model and the hydrogen energy utilization unit model, a step-by-step carbon trading cost model is constructed according to the baseline method to form a system low-carbon economic constraint; The coal consumption cost, the gas purchase and abandoned wind and light cost and the carbon trading cost are integrated, and a low-carbon economic dispatching model of the comprehensive energy system is established in combination with operation constraints of each unit; The optimal operation parameters of each unit are output by solving the dispatching model in step 4 through Gurobi.

2. The method of claim 1, wherein: The coal-ammonia mixed combustion model of the thermal power unit is constructed to analyze the low-carbon emission characteristics of the thermal power unit in ammonia mixed combustion, and the model is as follows: The ammonia and coal mixed combustion in the thermal power unit can effectively realize clean energy utilization of the unit; wherein, , , are the coal consumption coefficients of the thermal power unit, respectively; is the output power of the thermal power unit; is the coal consumption of the thermal power unit after ammonia doping; is the ammonia consumption of the thermal power unit; and are the low calorific values of ammonia and coal, respectively; A carbon capture device is installed to absorb carbon emissions, wherein the energy consumption of the carbon capture device includes fixed energy consumption and operation energy consumption, and the operation energy consumption mainly depends on the carbon capture amount of the carbon capture device, and the model is as follows: In the formula, and respectively are carbon emission and carbon emission coefficient of the thermal power generating unit; is the flue gas split ratio of the thermal power generating unit; is the carbon capture efficiency; is the amount of carbon dioxide to be captured supplied by the solution storage; is the total amount of captured carbon dioxide; is the energy consumption per unit mass of captured carbon dioxide; and respectively are the operating and fixed energy consumption of the carbon capture device; is the net output power of the thermal power generating unit.

3. The method of claim 2, wherein: The hydrogen energy utilization unit includes an electrolytic tank, a hydrogen storage tank, a hydrogen fuel cell, a methane reactor and an ammonia production device.

4. The method of claim 3, wherein: The optimal dispatching strategy of the comprehensive energy system considering multi-energy flow includes an electrolytic tank model, and the electrolytic tank model is as follows: The electrolytic tank model is as follows: wherein, and are the electrolyzer electrical energy input and hydrogen energy output, respectively; and are the upper and lower limits of the electrolyzer electrical energy input, respectively; and are the upper and lower limits of the electrolyzer electrical energy input ramp, respectively.

5. The method of claim 3, wherein: The optimal dispatching strategy of the comprehensive energy system considering multi-energy flow includes a hydrogen storage tank model, and the hydrogen storage tank model is as follows: wherein, is the remaining hydrogen amount of the hydrogen storage tank; is the loss coefficient of the hydrogen storage tank; and are the hydrogen charging power and hydrogen discharging power of the hydrogen storage tank, respectively; and is the hydrogen charging and discharging efficiency of the hydrogen storage tank; and are binary variables, respectively representing the hydrogen charging and discharging state of the hydrogen storage tank; and are the maximum operating powers of the hydrogen charging and discharging of the hydrogen storage tank, respectively; and are the initial period and final period hydrogen storage amounts of the hydrogen storage tank, respectively; and are the upper and lower limits of the hydrogen storage amount of the hydrogen storage tank, respectively.

6. The method of claim 3, wherein: The optimal dispatching strategy of the comprehensive energy system considering multi-energy flow includes an ammonia production device model, and the ammonia production device model is as follows: wherein, and are the hydrogen input and ammonia output of the ammonia production plant, respectively; is the ammonia production efficiency; is the heat release ratio of the ammonia production plant; is the ammonia mass produced by the ammonia production plant; is the heat power released per unit mass of ammonia produced; is the heat power provided to the ammonia production plant; and are the upper and lower limits of the hydrogen input of the ammonia production plant; and are the upper and lower limits of the hydrogen input ramp of the ammonia production plant.

7. The method of claim 3, wherein: The optimal dispatching strategy of the comprehensive energy system considering multi-energy flow includes a gas turbine unit model, and the gas turbine unit model is as follows: wherein, Pz is the energy input power of the gas turbine unit z; and PzH and PzN are the hydrogen energy and natural gas input of the gas turbine unit z, respectively; and PzE and PzH are the electrical and thermal energy output of the gas turbine, respectively; and ηz and ηz are the energy conversion efficiency of the gas turbine and the gas turbine unit, respectively; and Pzmin and Pzmax are the lower and upper limits of the input power of the gas turbine unit z, respectively; and Pzmin and Pzmax are the lower and upper limits of the input power ramp of the gas turbine unit z, respectively; and Pzmin and Pzmax are the lower and upper limits of the hot spot output ratio of the gas turbine, respectively.

8. The method of claim 3, wherein: The optimal dispatching strategy of the comprehensive energy system considering multi-energy flow includes a methane reactor model, and the methane reactor model is as follows: wherein and are the methane reactor hydrogen input and natural gas output, respectively; is the natural gas production efficiency; is the methane reactor heat supply release ratio; is the heat power released per unit of natural gas produced; is the heat power supplied by the methane reactor; is the amount of carbon dioxide consumed by the methane reactor; and are the upper and lower limits of the hydrogen input to the ammonia production plant; and are the upper and lower limits of the hydrogen input ramp to the ammonia production plant.

9. The method of claim 2, wherein: In the step-by-step carbon trading cost model constructed according to the baseline method, the transaction cost calculation mode of the carbon trading cost is as follows: In the formula, is the carbon trading base price, is the quota for participating in carbon market transactions, and is the carbon trading price growth rate; is the carbon trading price growth interval.

10. The method of claim 2, wherein: The integrated coal consumption cost, gas purchase and wind / solar curtailment costs, and carbon trading costs, combined with the operational constraints of each unit, establish a comprehensive energy system low-carbon economic dispatch model. Specifically, this model uses the unit coal consumption cost as the basis for the low-carbon economic dispatch. Gas purchase cost Equipment operation and maintenance costs Cost of curtailed renewable energy Carbon trading costs And carbon capture integration cost sum The target is the minimum, and the specific calculation method is as follows: T is the total scheduling period; is the unit mass coal price; is the unit operation and maintenance cost of wind power; is the unit operation and maintenance cost of photovoltaic power; is the unit operation and maintenance cost of electrolytic cell; is the unit operation and maintenance cost of methane reactor; is the unit operation and maintenance cost of ammonia production device; is the unit operation and maintenance cost of gas turbine; is the unit operation and maintenance cost of gas boiler; is the unit operation and maintenance cost of hydrogen storage tank; is the time-of-use gas price of natural gas; is the unit power wind power and photovoltaic power curtailment cost; is the solution loss cost; is the daily depreciation cost of carbon capture device; is the carbon dioxide sequestration and transportation cost; is the alcohol amine solution cost coefficient; is the solution operation loss coefficient; is the alcohol amine solution volume required by the solution storage in the carbon capture device; is the unit carbon dioxide cost coefficient of transportation and sequestration; is the discount rate of carbon capture project; is the total cost of unit volume solution storage; and are the total costs of solution storage, respectively.

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