Electricity-hydrogen-garbage multi-energy system collaborative scheduling method based on phase change material heat storage

Abstract

The invention belongs to the technical field of energy scheduling, and particularly relates to an electricity-hydrogen-garbage multi-energy system collaborative scheduling method based on phase change material heat storage. Comprising the steps that firstly, a phase change material heat storage coupling alkaline electrolytic cell waste heat recovery and heat pump synergistic multi-stage heat management system is constructed to achieve space-time translation storage of hydrogen production waste heat, and a heat pump is combined to establish a multi-heat-source complementary garbage drying system; secondly, by providing a flue gas treatment method which comprises a flue gas storage device and is firstly purified and then separated, space-time decoupling of waste incineration power generation and flue gas treatment is achieved; and finally, on the basis of a model prediction control theory, constructing a two-stage optimization scheduling strategy combining day-ahead economic scheduling and intra-day rolling, and verifying the feasibility and superiority of the proposed system architecture and scheduling strategy through a simulation example. According to the system provided by the invention, the economy and flexibility of the system are remarkably improved through multi-dimensional cooperation of waste heat recovery, garbage drying and a flexible scheduling mechanism.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy scheduling, and in particular relates to a coordinated scheduling method for an electricity-hydrogen-waste multi-energy system based on phase change material heat storage. Background Art

[0002] As an efficient method for treating municipal solid waste, waste incineration power generation not only reduces waste and renders it harmless, but also enables the effective recycling of resources. In the context of global low-carbon development, the traditional fossil fuel-dominated energy system is facing multiple challenges, including resource shortages, environmental pollution, and excessive carbon emissions. The large-scale deployment of renewable energy sources such as wind power and photovoltaics injects clean power into the energy system, but their inherent randomness and volatility lead to prominent problems of wind and solar power curtailment, which seriously restricts the absorption of new energy. Therefore, studying the coordinated operation of waste incineration power plants and renewable energy is of great significance to the low-carbon and clean energy transformation of cities.

[0003] The characteristics of municipal solid waste (MSW) are significantly influenced by the geographical environment, economic development, and the living standards of residents. There are systematic differences between MSW and developed countries in terms of composition and thermodynamic properties. In my country, food waste generally accounts for 50%-60% of MSW. This high organic matter content results in a moisture content generally ranging from 40% to 60%. This high moisture content not only increases the difficulty and cost of waste disposal but also reduces the calorific value of the waste, limiting the energy recovery efficiency of waste incineration. While existing research focuses on improving the efficiency of waste incineration power plants by recovering waste heat from flue gas, it does not effectively store the recovered heat energy. Furthermore, flue gas temperature fluctuates significantly, and using waste heat recovery for drying presents problems such as unstable heat supply, a single heat source, and poor system flexibility.

[0004] In fact, a variety of heat sources can be used for garbage drying, among which alkaline electrolyzers have shown good application prospects. Alkaline electrolyzers generate a large amount of waste heat during operation, accounting for about 20-30% of the input energy. Alkaline electrolyzers use renewable energy to produce hydrogen and recover waste heat, which greatly improves energy utilization efficiency while promoting wind and solar power consumption. In addition, alkaline electrolyzers have the advantages of mature technology and low equipment cost. They are currently suitable for large-scale engineering applications. However, although existing research has made significant progress in the recovery of waste heat from alkaline electrolyzers, none of them involve the storage of recovered heat energy, which to a certain extent limits the further improvement of energy utilization efficiency.

[0005] In the field of thermal energy storage research, phase change materials (PCMs) have attracted widespread attention as a new type of heat storage medium. Phase change materials achieve efficient thermal energy storage and release by absorbing or releasing a large amount of phase change latent heat, and exhibit quasi-isothermal characteristics during the phase change process. Their high energy storage density and small size enable efficient and stable thermal energy regulation in thermal management systems. However, phase change materials are currently mainly used in building structures, electronic devices, and solar thermal systems. Research on their application in alkaline electrolyzer waste heat recovery and garbage drying is still relatively scarce and urgently needs further in-depth exploration.

[0006] Therefore, in order to solve the problem of coordinated optimization of energy efficiency improvement of waste incineration power plants and renewable energy consumption, this paper proposes an optimization scheduling method for an electricity-hydrogen-heat-waste multi-energy coordinated system based on phase change material heat storage. Summary of the Invention

[0007] The purpose of the present invention is to provide a coordinated scheduling method for an electricity-hydrogen-heat-garbage multi-energy system based on phase change material heat storage. The present invention significantly improves the economy and flexibility of the system through the multi-dimensional coordination of waste heat recovery, garbage drying and flexible scheduling mechanism, and at the same time has the ability to reduce peaks and fill valleys, providing an innovative technical path for the resource utilization of urban domestic waste and the low-carbon transformation of energy systems.

[0008] To solve the above technical problems, the present invention provides a coordinated scheduling method for an electricity-hydrogen-waste multi-energy system based on phase change material heat storage, comprising:

[0009] First, a multi-stage thermal management system is constructed, combining phase change material heat storage with waste heat recovery from alkaline electrolyzers and heat pumps to achieve spatiotemporal storage of waste heat from hydrogen production. This is then combined with heat pumps to establish a waste drying system with multiple heat sources complementing each other.

[0010] Secondly, a flue gas treatment method with a flue gas storage device, which involves purification followed by separation, is proposed to achieve spatiotemporal decoupling of waste incineration power generation and flue gas treatment.

[0011] Finally, based on model predictive control theory, a two-stage optimization scheduling strategy combining day-ahead economic scheduling and intraday rolling scheduling is constructed, and the feasibility and superiority of the proposed system architecture and scheduling strategy are verified through simulation examples.

[0012] Preferably, the system architecture includes: a system power generation unit and a power consumption unit; the system power generation unit includes a wind power plant, a photovoltaic power plant and a waste incineration power plant; the power consumption unit includes an alkaline electrolyzer, a heat pump, a flue gas purification device and a flue gas separation device; the excess electricity of the system is supplied to the upper power grid through electricity sales, and the alkaline electrolyzer supplies hydrogen load by electrolyzing water to produce hydrogen; in the waste incineration power plant, waste treatment adopts a process flow of drying first and then incineration to generate electricity, wherein the heat required for drying is provided by phase change materials, and the heat energy of the phase change materials comes from the alkaline electrolyzer and the heat pump.

[0013] It also includes a flue gas storage device, which is arranged between the waste incineration power plant and the flue gas purification device to achieve the separation of flue gas treatment and waste incineration power generation.

[0014] Preferably, an alkaline electrolyzer model is constructed to ensure that the power consumption of the alkaline electrolyzer is always in dynamic balance with the power of hydrogen production and heat generation; and to ensure that the daily hydrogen production of the alkaline electrolyzer is constant to meet the hydrogen load demand of the user;

[0015] The alkaline electrolytic cell model is shown in the following formulas (1)-(6):

[0016]

[0017]

[0018] Where: P t H 、 is the hydrogen production, heat generation and power consumption of the electrolyzer at time t, η EL is the electrolytic cell heat conversion efficiency, is the hydrogen production quality at time t, T is the final state, is the 0-1 state variable of the electrolytic cell, 1 represents the open state, 0 represents the closed state, is the daily hydrogen mass, H H is the calorific value of hydrogen, The upper and lower limits of the electrolytic cell power consumption, ΔP EL is the electrolytic cell climbing constraint, is the power consumption of the electrolytic cell at time t-1.

[0019] Preferably, a phase change material heat storage model is constructed, wherein the heat storage source of the phase change material includes the waste heat provided by the alkaline electrolytic cell heat recovery system and the heat energy generated by the heat pump through electrical energy conversion. When the phase change material releases the phase change latent heat, the output heat energy is used for garbage drying;

[0020] The phase change material heat storage model is shown in the following formulas (7)-(15):

[0021]

[0022] Where: is the heat pump power consumption at time t and time t-1, are the heat storage and heat release powers of the phase change material at time t, is the heat generation power of the electrolytic cell at time t, and are the heat storage of phase change material at time t and time t-1 respectively, and are the heat storage of phase change materials in the initial and final states, is the upper limit of heat pump output, are the upper limit of heat storage power and heat release power of phase change materials, are the upper and lower limits of heat storage of phase change materials, ΔP HP is the heat pump ramp constraint, η Abs ,η Exo are heat storage and heat release efficiency, η HP is the heat conversion efficiency of the heat pump, are the 0-1 state variables of the phase change material at time t, 1 indicates heat storage state, 1 indicates the exothermic state, δ PCM is the self-loss coefficient of the phase change material.

[0023] Preferably, a waste incineration power plant model is constructed to dynamically adjust the processing load of the waste incineration power plant according to actual needs;

[0024] The waste incineration power plant model is shown in the following formulas (16)-(22):

[0025]

[0026] Where: P is the heat release power of the phase change material at time t, t WI 、 are the power generation capacity of the waste incineration power plant at time t and time t-1 respectively, is the mass of the garbage incinerated at time t, is the moisture content of the incinerated garbage at time t, m All The daily garbage processing volume. are the upper and lower limits of garbage mass, γ W is the garbage drying coefficient, a and b are the garbage power generation coefficients, is the initial moisture content of garbage, are the upper and lower limits of garbage moisture content, are the upper and lower limits of the waste incineration power plant output, ΔP WIis the ramp constraint of the waste incineration power plant, and T is the state at the final moment.

[0027] Preferably, a flue gas treatment model is constructed, wherein the flue gas first passes through a flue gas purification device to remove pollutants, and then passes through a flue gas separation device to effectively separate CO2 gas, and a flue gas storage device is introduced to achieve decoupled operation of the flue gas treatment system and the waste incineration power generation system;

[0028] The flue gas treatment model is shown in the following formulas (23)-(34):

[0029] P t F =ω F ·V t F (twenty three)

[0030] e F ·P t WI =V t RT +V t GI (twenty four)

[0031] V t F =V t RT +V t GO (25)

[0032]

[0033] P t C =ω C ·V t C (27)

[0034] V t C =α·β·V t F (28)

[0035]

[0036]

[0037] u GI +u GO ≤1 (34)

[0038] Where: P t F is the flue gas purification power at time t, P t Cis the CO2 separation power of flue gas at time t, V t G is the gas storage capacity of the flue gas storage device at time t, V0 G 、 The gas storage capacity of the smoke storage device at the initial state, t-1 moment and final moment, V t F is the amount of flue gas purified at time t, P t WI is the power generation capacity of the waste incineration power plant at time t, V t RT 、V t GO are the flue gas volumes flowing into the flue gas treatment device from the waste incineration power plant and the flue gas storage device at time t, V t GI is the amount of flue gas flowing into the flue gas storage device from the waste incineration power plant at time t, V t C is the amount of CO2 separated from flue gas at time t, is the upper limit of the gas storage device capacity, is the upper limit of the flue gas duct flow rate, u GI 、u GO are the 0-1 state variables of the smoke storage device, 1 means flue gas flows in, 1 means flue gas outflow, ω F is the flue gas purification power consumption coefficient, ω C is the flue gas separation power consumption coefficient, e F is the flue gas emission coefficient, α is the proportion of CO2 in the flue gas, and β is the CO2 separation rate.

[0039] Preferably, the two-stage optimization scheduling strategy includes: the electricity-hydrogen-heat-waste coupling system adopts a two-stage optimization scheduling strategy of the day before and within the day. In the day-ahead scheduling stage, with 1 hour as the time scale and 24 hours as the scheduling cycle, the optimal operation plan of each subsystem within the scheduling cycle is obtained; the day-ahead scheduling takes minimizing the net cost within the scheduling cycle as the optimization goal, the system cost includes the flue gas treatment cost and the carbon trading cost, and the income is the system's grid-connected income; in the intraday scheduling stage, a rolling optimization method is adopted, with 15 minutes as the optimization step and 4 hours as the rolling window, to make fine adjustments to the day-ahead scheduling plan and respond to real-time changes in system operation in a timely manner; the intraday scheduling is based on the optimization results of the day-ahead scheduling, and performs rolling optimization based on the model predictive control theory, and corrects the prediction deviation of the day-ahead scheduling plan in real time to adjust the output of each device, the heat storage capacity of the phase change material and the gas storage capacity of the flue gas storage device to ensure that the system meets the real-time balance of electricity, heat and flue gas.

[0040] Preferably, the objective function of the day-ahead scheduling is as shown in the following formulas (35)-(38), and the constraint conditions include, in addition to the constraints related to each device, a system power balance constraint, as shown in the following formula (39);

[0041]

[0042] Where: F ah is the minimum net cost of the system's day-ahead scheduling, is the flue gas treatment cost at time t, is the carbon trading cost at time t, is the income from Internet access at time t, k F is the unit cost of flue gas treatment, V t C is the amount of CO2 separated from flue gas at time t, k C is the unit price of carbon trading, α is the proportion of CO2 in flue gas, β is the CO2 separation rate, V t F is the amount of flue gas purified at time t, e C is the carbon emission allocation coefficient, is the on-grid electricity price at time t, k H is the unit price of hydrogen, T is the final state, P t WT is the power generated by the wind power plant at time t, P t PV is the power generated by the photovoltaic power plant at time t, P t WI is the power generation capacity of the waste incineration power plant at time t, P t EL is the power consumption of the electrolytic cell at time t, P t F is the flue gas purification power at time t, P t C is the CO2 separation power of flue gas at time t, P t HP P is the power consumption of the heat pump at time t, t E is the Internet power at time t.

[0043] Preferably, the objective function of the intraday scheduling is shown in the following formula (40). The constraints are similar to those of the day-ahead scheduling. However, due to the change in the time dimension, the time scale changes from 1 hour to 15 minutes, and the constraints of the corresponding devices need to be adjusted, as shown in the following formulas (41)-(45):

[0044]

[0045] Where: F inis the minimum net cost of system daily scheduling, and M is defined as the prediction interval of MPC.

[0046] Preferably, the feasibility and superiority of the proposed system architecture and scheduling strategy are verified through simulation examples, including: based on the mixed integer linear programming method, using the Yalmip toolbox in Matlab for modeling, and calling the Gurobi solver for optimization and solution.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. By incorporating heat recovery from alkaline electrolyzers and phase-change material energy storage technology, this system can utilize wind power to drive the electrolyzer to produce hydrogen through water electrolysis during periods of low electricity prices. This system also uses a heat pump to achieve electrical-to-heat conversion, while simultaneously storing the heat in the phase-change material. During periods of high electricity prices, the system releases the heat stored in the phase-change material to dry the waste, which is then incinerated in an incinerator to generate electricity, thus achieving peak load shifting and valley filling.

[0049] 2. The two-stage optimization scheduling strategy proposed in this invention can reduce the negative impact of prediction errors on the balance of electricity, heat and flue gas, optimize the output and operating status of each device in the system, thereby maximizing the net profit of the system and improving the economy and reliability of the system operation.

[0050] 3. The strategy proposed in this invention not only optimizes the spatiotemporal distribution of energy, but also significantly improves the energy utilization efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a flow chart of the collaborative scheduling method of the electricity-hydrogen-waste multi-energy system based on phase change material heat storage provided by the present invention.

[0052] Figure 2 This is a composition diagram of the electricity-hydrogen-heat-waste multi-energy system architecture provided by the present invention.

[0053] Figure 3 This is a flow chart of the two-stage day-ahead and day-intraday optimization scheduling strategy provided by the present invention.

[0054] Figure 4 This is the electricity price curve provided by the present invention.

[0055] Figure 5 This is a diagram of the power balance simulation results of Scheme 1 provided by the present invention.

[0056] Figure 6 This is a diagram of the thermodynamic balance simulation results of Scheme 1 provided by the present invention.

[0057] Figure 7 This is a diagram of the flue gas balance simulation results of Scheme 1 provided by the present invention.

[0058] Figure 8 This is a diagram of the power balance simulation results of Scheme 2 provided by the present invention.

[0059] Figure 9 This is a diagram of the thermodynamic balance simulation results of Scheme 2 provided by the present invention.

[0060] Figure 10 This is a diagram of the flue gas balance simulation results of Scheme 2 provided by the present invention.

[0061] Figure 11 This is a diagram of the power balance simulation results of Solution 3 provided by the present invention.

[0062] Figure 12 This is a diagram of the thermodynamic balance simulation results of Scheme 3 provided by the present invention.

[0063] Figure 13 This is a diagram of the flue gas balance simulation results of Scheme 3 provided by the present invention. DETAILED DESCRIPTION

[0064] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are greatly simplified and not to exact scale, and are only used to facilitate and clearly illustrate the embodiments of the present invention.

[0065] like Figure 1 As shown, an embodiment of the present invention specifically provides an electric-hydrogen-garbage multi-energy system based on phase change material heat storage. First, an alkaline electrolyzer is used to electrolyze water to produce hydrogen to meet the hydrogen load demand, and a phase change material is used to store the waste heat generated during the hydrogen production process. At the same time, a heat pump is introduced to heat the phase change material, thereby realizing multi-stage energy utilization. Furthermore, a phase change material is used as a heat source to pre-dry the garbage, effectively reducing the moisture content of the garbage and increasing the calorific value of the garbage entering the furnace, thereby improving the efficiency of the garbage incineration power plant. Then, a process route of first purifying and then separating CO2 is adopted, and by introducing a flue gas storage device, the independent operation of garbage incineration power generation and flue gas treatment processes is realized. Finally, based on the model predictive control theory, a two-stage scheduling strategy combining day-ahead and day-intraday is proposed, and the feasibility and superiority of the proposed system architecture and scheduling strategy are verified through simulation examples.

[0066] like Figure 2The figure shows the architecture of the electric-hydrogen-heat-waste multi-energy system of an embodiment of the present invention. The system's power generation unit consists of a wind power plant (WT), a photovoltaic power plant (PV) and a waste incineration power plant (WIP). The power consumption unit includes an alkaline electrolyzer (EL), a heat pump (HP), a flue gas purification device (FPF) and a flue gas separation device (FSP). The system's excess electricity is supplied to the upper grid (Grid) through electricity sales. The alkaline electrolyzer produces hydrogen by electrolyzing water to supply the hydrogen load (Hydrogen Load). In the waste incineration power plant, waste treatment adopts a process of drying first and then incineration to generate electricity. The heat required for drying is provided by a phase change material (PCM), and the heat energy of the phase change material comes from the electrolyzer and the heat pump. In addition, a flue gas storage device (FST) is added to achieve the separation of flue gas treatment and waste incineration power generation. Through multi-energy collaborative optimization, the system achieves efficient integration of renewable energy, hydrogen energy, heat energy and waste treatment.

[0067] Preferably, the alkaline electrolyzer model provided in an embodiment of the present invention is as follows: the alkaline electrolyzer decomposes water into hydrogen and oxygen through an electrochemical reaction, accompanied by significant heat release. Without considering energy losses during the electrolysis reaction, the electrolyzer's power consumption always maintains a dynamic balance with the power of hydrogen production and heat generation. The electrolyzer's daily hydrogen production is constant, used to meet the user's hydrogen load demand. The alkaline electrolyzer model is shown in formulas (1)-(6).

[0068] P t H =η EL ·P t EL (1)

[0069]

[0070] Where: P t H 、 P t EL For the electrolyzer to produce hydrogen, heat and power, is the hydrogen production mass at time t, is the 0-1 state variable of the electrolytic cell, 1 represents the open state, 0 represents the closed state, is the daily hydrogen mass, H H is the calorific value of hydrogen, The upper and lower limits of the electrolytic cell power consumption, ΔP EL It is the climbing constraint of the electrolytic cell.

[0071] Preferably, the phase change material heat storage model provided in the embodiments of the present invention is as follows: The phase change material energy storage source includes two components: waste heat provided by the alkaline electrolyzer heat recovery system, and heat energy generated by the heat pump through electrical energy conversion. When the phase change material releases its latent heat, the output heat energy is used for waste drying. The phase change material energy storage model is shown in equations (7)-(15).

[0072]

[0073]

[0074] Where: P t HP is the power consumption of the heat pump, are the heat storage and heat release power of phase change materials, Heat storage for phase change materials, is the upper limit of heat pump output, are the upper limit of heat storage power and heat release power of phase change materials, are the upper and lower limits of heat storage of phase change materials, ΔP HP is the heat pump ramp constraint, η Abs ,η Exo are heat storage and heat release efficiency, η HP is the heat conversion efficiency of the heat pump, are the 0-1 state variables of the phase change material, 1 indicates heat storage state, 1 indicates the exothermic state, δ PCM is the self-loss coefficient of the phase change material.

[0075] Preferably, the waste incineration power plant model provided by the embodiment of the present invention is as follows: the heat required for the waste drying process and the amount of power generated by waste incineration are closely related to the moisture content of the waste and the treatment quality. The total daily waste treatment volume of the waste incineration power plant remains constant, but its treatment load can be dynamically adjusted according to actual needs. The waste incineration power plant model is shown in formulas (16)-(22):

[0076]

[0077] Where: P t WI Generates power for waste incineration power plants. For the quality of garbage incinerated in the furnace, is the moisture content of the garbage entering the incineration furnace, m All The daily garbage processing volume. are the upper and lower limits of garbage mass, γ W is the garbage drying coefficient, a and b are the garbage power generation coefficients, is the initial moisture content of garbage, are the upper and lower limits of garbage moisture content, are the upper and lower limits of the waste incineration power plant output, ΔP WI Ramping constraints for waste incineration power plants.

[0078] Preferably, the flue gas treatment model provided in the embodiment of the present invention is as follows: During the incineration process, a waste incineration power plant generates a large amount of flue gas, which contains a variety of pollutants and greenhouse gases such as CO2. The flue gas first passes through a purification system to remove pollutants, and then passes through a CO2 separation device to effectively separate greenhouse gases. To further optimize system operation, a flue gas storage device is introduced to achieve decoupled operation of the flue gas treatment system and the waste incineration power generation system. The flue gas treatment model is shown in formulas (23)-(34):

[0079] P t F =ω F ·V t F (twenty three)

[0080] e F ·P t WI =V t RT +V t GI (twenty four)

[0081] V t F =V t RT +V t GO (25)

[0082]

[0083] P t C =ω C ·V t C (27)

[0084] V t C =α·β·V t F (28)

[0085]

[0086]

[0087] u GI +u GO ≤1 (34)

[0088] Where: P t F is the flue gas purification power, P t C is the CO2 separation power of flue gas, V t G is the gas storage capacity of the flue gas storage device, V t F is the amount of flue gas to be purified, V t RT 、V t GO are the flue gas volumes flowing from the waste incineration power plant and the flue gas storage device into the flue gas treatment device, V t GI is the amount of flue gas flowing into the flue gas storage device from the waste incineration power plant, V t C is the amount of CO2 separated from flue gas, is the upper limit of the gas storage device capacity, is the upper limit of the flue gas duct flow rate, u GI 、u GO are the 0-1 state variables of the smoke storage device, 1 means flue gas flows in, 1 means flue gas outflow, ω F is the flue gas purification power consumption coefficient, ω C is the flue gas separation power consumption coefficient, e F is the flue gas emission coefficient, α is the proportion of CO2 in the flue gas, and β is the CO2 separation rate.

[0089] As a preference, the two-stage optimization scheduling strategy provided by the embodiment of the present invention is as follows: Figure 3 As shown in the figure, the electricity-hydrogen-heat-waste coupled system adopts a two-stage optimization scheduling strategy, day-ahead and intraday. In the day-ahead scheduling stage, the optimal operation plan for each subsystem within the scheduling cycle is obtained using a 1-hour time scale and a 24-hour scheduling cycle. In the intraday scheduling stage, a rolling optimization method is used with a 15-minute optimization step and a 4-hour rolling window to fine-tune the day-ahead scheduling plan and promptly respond to real-time changes in system operation.

[0090] Preferably, the day-ahead scheduling provided by the embodiments of the present invention optimizes the minimization of net costs within the scheduling cycle, taking into account the economic efficiency of system operation. System costs include flue gas treatment costs and carbon trading costs, and the revenue is the system's grid-connected revenue. The objective functions of day-ahead scheduling are shown in equations (35)-(38). In addition to the constraints related to each device, the constraints also include system power balance constraints, as shown in equation (39).

[0091]

[0092] P tWT +P t PV +P t WI =P t EL +P t F +P t C +P t HP +P t E (39)

[0093] Where: F ah is the minimum net cost of the system's day-ahead scheduling, is the flue gas treatment cost, is the carbon trading cost, For Internet access income. F is the unit cost of flue gas treatment, k C is the unit price of carbon trading, e C is the carbon emission distribution coefficient, P t E For Internet access power, is the on-grid electricity price, k H is the unit price of hydrogen.

[0094] Preferably, the intraday scheduling provided by the embodiment of the present invention is based on the optimization results of the day-ahead scheduling, and performs rolling optimization based on Model Predictive Control (MPC), and corrects the prediction deviation of the day-ahead scheduling plan in real time. The output of each device, the heat storage capacity of the phase change material and the gas storage capacity of the flue gas storage device are adjusted to ensure that the system meets the power, heat and flue gas balance in real time. The objective function of the intraday scheduling is shown in formula (40). The constraints are similar to those of the day-ahead scheduling, but due to the change in the time dimension, the time scale changes from 1 hour to 15 minutes, and the constraints of the corresponding devices need to be adjusted, as shown in formulas (41)-(45).

[0095]

[0096] Where: F in is the minimum net cost of system daily scheduling, and M is defined as the prediction interval of MPC.

[0097] As a preferred option, three operation schemes of the electricity-hydrogen-heat-waste coupling system are also included:

[0098] Option 1: Consider the comprehensive utilization of phase change material heat storage and alkaline electrolyzer heat recovery.

[0099] Option 2: Considering only the alkaline electrolyzer heat recovery system, without considering phase change material heat storage. The heat required for garbage drying is directly supplied by the electrolyzer heat recovery system and heat pump.

[0100] Option 3: Phase change material heat storage and alkaline electrolyzer heat recovery are not considered. The heat required for garbage drying is completely provided by the heat pump.

[0101] The simulation parameters used are: Taking a waste incineration power plant as an example, the flue gas purification, separation and storage devices are configured. The installed capacity of the waste incineration power plant is 150MW, and the daily waste processing capacity is m All =2000t, initial moisture content of garbage Garbage drying coefficient γ W =0.6782, waste power generation coefficient a=-1.405, b=0.946, phase change material heat storage and heat release efficiency η Abs =η Exo =0.98, self-loss coefficient δ PCM =0.01, rated power of electrolyzer 25MW, hydrogen production efficiency η EL =0.65, daily hydrogen mass The heat pump has a rated power of 20MW and a heat conversion efficiency of η HP =2.5, smoke emission coefficient e F =0.96, flue gas purification power consumption coefficient ω F =0.513, flue gas separation power consumption coefficient ω C =0.23, carbon emission allocation coefficient e C =0.472, carbon trading unit price k C =90￥ / t, unit cost of flue gas treatment k C = 149.52￥ / t, 24h on-grid electricity price Figure 4 shown.

[0102] Simulation results analysis: To verify the correctness and effectiveness of the proposed model, the Yalmip toolbox in Matlab was used to build the model based on the Mixed-Integer Linear Programming (MILP) method, and the Gurobi solver was called for optimization and solution. The simulation results of the electric-hydrogen-heat-waste coupling system under various operation schemes are shown in the figure below. Figures 5 to 13 shown.

[0103] Depend on Figure 4As can be seen, wind power output exhibits a relatively even distribution over time, with peak wind power generation occurring between 21:00 and 5:00 the following day. However, the on-grid electricity price during this period is relatively low, so wind power is primarily used to power the alkaline electrolyzer for water electrolysis and hydrogen production, as well as the heat pump for electrical-to-heat conversion, to meet the system's daily hydrogen load and phase change material heat storage needs. Photovoltaic power output is limited by sunlight intensity and only occurs between 7:00 and 19:00, peaking between 12:00 and 15:00. On-grid electricity prices are higher between 8:00 and 21:00. Since waste incineration plants process a fixed amount of waste daily, their power generation is primarily concentrated between 9:00 and 21:00, while the system's on-grid connection is concentrated between 7:00 and 21:00. The flue gas treatment process consists of two stages: purification and CO2 separation. There is a significant coupling relationship between the power consumption of flue gas purification and CO2 separation.

[0104] Depend on Figure 5 As can be seen, the system's daily hydrogen load demand is fixed, the electrolyzer recovers relatively little heat, and the phase change material's heat primarily comes from the heat pump's electrical heat conversion. The waste treatment process involves drying followed by incineration for power generation, creating a strong coupling between waste drying and incineration power generation. The quality and degree of waste treatment directly impact system operation: the greater the amount of waste processed per unit time, the more thorough the drying, the greater the heat required, and the correspondingly increased incineration power generation. Between 2:00 PM and 3:00 PM, the heat absorbed by waste drying is zero, and during this period, electricity prices are lower, so waste is incinerated without drying for power generation. Between 8:00 PM and 9:00 PM, the phase change material's heat storage capacity is low, so the drying process ceases. The phase change material's heat storage and discharge processes are completely decoupled. When the electrolyzer and heat pump are operating, the phase change material's heat storage capacity increases; when the waste drying process absorbs heat, its heat storage capacity decreases. The system concentrates waste drying and incineration during peak electricity price periods.

[0105] Depend on Figure 6 As can be seen, the introduction of flue gas storage devices decouples waste incineration power generation from flue gas treatment. During periods of high electricity prices, the flue gas storage devices can temporarily store flue gas generated by waste incineration, allowing flue gas treatment to proceed when electricity prices are lower. However, due to the capacity constraints of the flue gas storage devices, a certain connection between flue gas treatment and waste incineration power generation still exists.

[0106] Depend on Figures 7 to 9As can be seen, in Scheme 2, after removing the phase change material heat storage, the heat released by the electrolyzer and heat pump cannot be stored and must be used in real time for waste drying. This results in a strong coupling between the heat released by the electrolyzer and heat pump and the heat absorbed by the waste drying process. Compared to Scheme 1, the electrolyzer power consumption in Scheme 2 is essentially the same, but waste incineration power generation continues throughout the 24-hour period, and the flue gas inflow to the flue gas storage device is more dispersed. Between 8:00 and 22:00, the electrolyzer and heat pump are shut down, and the waste is incinerated directly to generate electricity without drying. Because electricity prices are higher during this period and the electrolyzer's hydrogen production during other hours already meets the system's daily hydrogen load, direct incineration power generation and the use of this electricity for grid connection and flue gas treatment are more rational. Although Scheme 2 and Scheme 1 process the same total daily waste, Scheme 2's overall power generation is reduced due to the lower heat absorption and drying degree of the waste in Scheme 2.

[0107] Depend on Figures 10 to 13 As can be seen, in Scheme 3, without considering phase change material heat storage and electrolyzer heat recovery, the heat required for waste drying is entirely supplied by the heat pump, resulting in a strong coupling between the heat released by the heat pump and the heat absorbed by the waste drying process. In Scheme 3, waste drying occurs only between 10:00 PM and 8:00 AM the following day. During this period, waste incineration power generation and wind power are primarily used to power the electrolyzer for hydrogen production and flue gas treatment. The power supplied to the heat pump is only half that of Scheme 1, and the heat released by the electrolyzer is not utilized. Therefore, Scheme 3 achieves a lower degree of waste drying and reduces waste incineration power generation. Although Scheme 3's electrical power, thermal power, and flue gas balance are similar to those of Scheme 2, the heat pump consumes more power because it does not utilize the heat released by the electrolyzer.

[0108] Table 1: Comparison of benefits and costs of different solutions (unit: yuan)

[0109] plan Flue gas treatment costs Carbon trading costs Internet access income Net profit Solution 1 89928.835 -33934.764 671836.704 615842.633 Option 2 76048.775 -28697.105 630674.291 583322.621 Option 3 75762.178 -28588.958 625560.308 578387.088

[0110] Table 1 shows the operating costs and benefits of each system scheme. Scheme 1 has the highest waste incineration power plant output and produces the most flue gas, resulting in the highest flue gas treatment costs. Since carbon emission quotas are proportional to output, Scheme 1 has the highest carbon emission quotas, the lowest carbon trading costs, and the highest on-grid revenue and net profit. Scheme 2 significantly reduces flue gas treatment costs, significantly reducing the system's on-grid revenue, leading to a significant decrease in net profit. Scheme 2's carbon trading costs are lower than those of Scheme 1, but the change is small, indicating that phase change material heat storage has a limited impact on carbon trading. Scheme 3's on-grid revenue further decreases, and net profit further declines. Overall, Scheme 1's net profit increases by approximately 5.28% compared to Scheme 2 and by approximately 6.08% compared to Scheme 3, indicating that phase change material heat storage and electrolyzer heat recovery significantly improve the system's economic benefits.

[0111] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A coordinated scheduling method for an electricity-hydrogen-waste multi-energy system based on phase change material heat storage, characterized in that: include: First, a multi-stage thermal management system is constructed, combining phase change material heat storage with waste heat recovery from alkaline electrolyzers and heat pumps to achieve spatiotemporal storage of waste heat from hydrogen production. This is then combined with heat pumps to establish a waste drying system with multiple heat sources complementing each other. Secondly, a flue gas treatment method with a flue gas storage device, which involves purification followed by separation, is proposed to achieve spatiotemporal decoupling of waste incineration power generation and flue gas treatment. Finally, based on model predictive control theory, a two-stage optimization scheduling strategy combining day-ahead economic scheduling and intraday rolling scheduling is constructed, and the feasibility and superiority of the proposed system architecture and scheduling strategy are verified through simulation examples.

2. The coordinated scheduling method for the electricity-hydrogen-waste multi-energy system based on phase change material heat storage according to claim 1, characterized in that: The system architecture includes: a system power generation unit and a power consumption unit; the system power generation unit includes a wind power plant, a photovoltaic power plant, and a waste incineration power plant; the power consumption unit includes an alkaline electrolyzer, a heat pump, a flue gas purification device, and a flue gas separation device; the system's excess electricity is supplied to the upper power grid through electricity sales, and the alkaline electrolyzer produces hydrogen by electrolyzing water to supply hydrogen load; in the waste incineration power plant, waste is treated using a process flow of drying followed by incineration to generate power, wherein the heat required for drying is provided by a phase change material, the heat energy of which is derived from the alkaline electrolyzer and the heat pump; It also includes a flue gas storage device, which is arranged between the waste incineration power plant and the flue gas purification device to achieve the separation of flue gas treatment and waste incineration power generation.

3. The coordinated scheduling method for the electricity-hydrogen-waste multi-energy system based on phase change material heat storage according to claim 1, characterized in that: It also includes an alkaline electrolyzer model that is constructed to maintain a dynamic balance between the power consumption of the alkaline electrolyzer and the power of hydrogen production and heat generation; and to ensure that the daily hydrogen production of the alkaline electrolyzer is constant to meet the hydrogen load demand of users; The alkaline electrolytic cell model is shown in the following formulas (1)-(6): P.S t H Hη EL ·P t EL (1) Where: P t H 、 P t EL is the hydrogen production, heat generation and power consumption of the electrolyzer at time t, η EL is the electrolytic cell heat conversion efficiency, is the hydrogen production quality at time t, T is the final state, is the 0-1 state variable of the electrolytic cell, 1 represents the open state, 0 represents the closed state, is the daily hydrogen mass, H H is the calorific value of hydrogen, The upper and lower limits of the electrolytic cell power consumption, ΔP EL is the electrolytic cell climbing constraint, is the power consumption of the electrolytic cell at time t-1.

4. The coordinated scheduling method for the electricity-hydrogen-waste multi-energy system based on phase change material heat storage according to claim 1, characterized in that: The invention also includes a phase change material heat storage model, wherein the heat storage source of the phase change material includes waste heat provided by the alkaline electrolyzer heat recovery system and heat energy generated by the heat pump through electrical energy conversion. When the phase change material releases the phase change latent heat, the output heat energy is used for garbage drying; The phase change material heat storage model is shown in the following formulas (7)-(15): Where: P t HP 、 is the heat pump power consumption at time t and time t-1, are the heat storage and heat release powers of the phase change material at time t, is the heat generation power of the electrolytic cell at time t, and are the heat storage of phase change material at time t and time t-1 respectively, and are the heat storage of phase change materials in the initial and final states, is the upper limit of heat pump output, are the upper limit of heat storage power and heat release power of phase change materials, are the upper and lower limits of heat storage of phase change materials, ΔP HP is the heat pump ramp constraint, η Abs ,η Exo are heat storage and heat release efficiency, η HP is the heat conversion efficiency of the heat pump, are the 0-1 state variables of the phase change material at time t, 1 indicates heat storage state, 1 indicates the exothermic state, δ PCM is the self-loss coefficient of the phase change material.

5. The coordinated scheduling method for the electricity-hydrogen-waste multi-energy system based on phase change material heat storage according to claim 1, characterized in that: Also included is a constructed waste incineration power plant model to dynamically adjust the processing load of the waste incineration power plant according to actual demand; The waste incineration power plant model is shown in the following formulas (16)-(22): Where: P is the heat release power of the phase change material at time t, t WI 、 are the power generation capacity of the waste incineration power plant at time t and time t-1 respectively, is the mass of the garbage incinerated at time t, is the moisture content of the incinerated garbage at time t, m All The daily garbage processing volume. are the upper and lower limits of garbage mass, γ W is the garbage drying coefficient, a and b are the garbage power generation coefficients, is the initial moisture content of garbage, are the upper and lower limits of garbage moisture content, are the upper and lower limits of the waste incineration power plant output, ΔP WI is the ramp constraint of the waste incineration power plant, and T is the state at the final moment.

6. The coordinated scheduling method for the electricity-hydrogen-waste multi-energy system based on phase change material heat storage according to claim 1, characterized in that: The system also includes a flue gas treatment model. The flue gas first passes through a flue gas purification device to remove pollutants, and then passes through a flue gas separation device to effectively separate CO2 gas. A flue gas storage device is introduced to achieve decoupled operation of the flue gas treatment system and the waste incineration power generation system. The flue gas treatment model is shown in the following formulas (23)-(34): P t F =ω F ·V t F (23) yes F ·P t WI =V t RT +V t GI (24) V t F =V t RT +V t GO (25) P t C =ω C ·V t C (27) V t C =α·β·V t F (28) in GI +in GO ≤1 (34) Where: P t F is the flue gas purification power at time t, P t C is the CO2 separation power of flue gas at time t, V t G is the gas storage capacity of the flue gas storage device at time t, The gas storage capacity of the smoke storage device at the initial state, t-1 moment and final moment, V t F is the amount of flue gas purified at time t, P t WI is the power generation capacity of the waste incineration power plant at time t, V t RT 、V t GO are the flue gas volumes flowing into the flue gas treatment device from the waste incineration power plant and the flue gas storage device at time t, V t GI is the amount of flue gas flowing into the flue gas storage device from the waste incineration power plant at time t, V t C is the amount of CO2 separated from flue gas at time t, is the upper limit of the gas storage device capacity, is the upper limit of the flue gas duct flow rate, u GI 、u GO are the 0-1 state variables of the smoke storage device, 1 means flue gas flows in, 1 means flue gas outflow, ω F is the flue gas purification power consumption coefficient, ω C is the flue gas separation power consumption coefficient, e F is the flue gas emission coefficient, α is the proportion of CO2 in the flue gas, and β is the CO2 separation rate.

7. The coordinated scheduling method for the electricity-hydrogen-waste multi-energy system based on phase change material heat storage according to claim 1, characterized in that: The two-stage optimization scheduling strategy includes: the electricity-hydrogen-heat-waste coupling system adopts a two-stage optimization scheduling strategy for the day before and within the day. In the day-after scheduling stage, with a time scale of 1 hour and a scheduling cycle of 24 hours, the optimal operation plan of each subsystem within the scheduling cycle is obtained; the day-after scheduling takes minimizing the net cost within the scheduling cycle as the optimization goal, the system cost includes the flue gas treatment cost and the carbon trading cost, and the income is the system's grid-connected income; in the intraday scheduling stage, a rolling optimization method is adopted with an optimization step of 15 minutes and a rolling window of 4 hours to make fine adjustments to the day-after scheduling plan and respond to real-time changes in system operation in a timely manner; the intraday scheduling is based on the optimization results of the day-after scheduling, and performs rolling optimization based on the model predictive control theory, and corrects the prediction deviation of the day-after scheduling plan in real time to adjust the output of each device, the heat storage capacity of the phase change material and the gas storage capacity of the flue gas storage device to ensure that the system meets the real-time balance of electricity, heat and flue gas.

8. The coordinated scheduling method for the electricity-hydrogen-waste multi-energy system based on phase change material heat storage according to claim 7, characterized in that: The objective function of the day-ahead scheduling is shown in the following formulas (35)-(38). In addition to the constraints related to each device, the constraints also include the system power balance constraint, as shown in the following formula (39): P t WT +P t PV +P t WI =P t EL +P t F +P t C +P t HP +P t E (39) Where: F ah is the minimum net cost of the system's day-ahead scheduling, is the flue gas treatment cost at time t, is the carbon trading cost at time t, is the income from Internet access at time t, k F is the unit cost of flue gas treatment, V t C is the amount of CO2 separated from flue gas at time t, k C is the unit price of carbon trading, α is the proportion of CO2 in flue gas, β is the CO2 separation rate, V t F is the amount of flue gas purified at time t, e C is the carbon emission allocation coefficient, is the on-grid electricity price at time t, k H is the unit price of hydrogen, T is the final state, P t WT is the power generated by the wind power plant at time t, P t PV is the power generated by the photovoltaic power plant at time t, P t WI is the power generation capacity of the waste incineration power plant at time t, P t EL is the power consumption of the electrolytic cell at time t, P t F is the flue gas purification power at time t, P t C is the CO2 separation power of flue gas at time t, P t HP P is the power consumption of the heat pump at time t, t E is the Internet power at time t.

9. The coordinated scheduling method for the electricity-hydrogen-waste multi-energy system based on phase change material heat storage according to claim 8, characterized in that: The objective function of intraday scheduling is shown in the following formula (40). The constraints are similar to those of day-ahead scheduling. However, due to the change in the time dimension, the time scale changes from 1 hour to 15 minutes. The constraints of the corresponding devices need to be adjusted as shown in the following formulas (41)-(45): Where: F in is the minimum net cost of system daily scheduling, and M is defined as the prediction interval of MPC.

10. The coordinated scheduling method for the electricity-hydrogen-waste multi-energy system based on phase change material heat storage according to claim 1, characterized in that: The feasibility and superiority of the proposed system architecture and scheduling strategy are verified through simulation examples, including: based on the mixed integer linear programming method, using the Yalmip toolbox in Matlab for modeling, and calling the Gurobi solver for optimization solution.

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