Comprehensive energy system optimization scheduling method considering methane reforming hydrogen production and fuel gas hydrogen doping

Abstract

The invention provides a comprehensive energy system optimization scheduling method considering biogas reforming hydrogen production and fuel gas hydrogen doping. The method comprises the steps that S1, a comprehensive energy system structure containing biogas reforming hydrogen production and fuel gas hydrogen doping is established; s2, establishing a methane reforming hydrogen production, hydrogen-doped gas turbine and stepped carbon transaction model; s3, establishing an optimal scheduling model of the comprehensive energy system containing methane reforming hydrogen production; s4, wind and light output, load and time-sharing electricity price data of the system are obtained; and S5, solving the scheduling model in the step S3, verifying the economical efficiency and low-carbon property of the methane reforming hydrogen production method, and analyzing the benefits of hydrogen-doped combustion. And multi-element production of hydrogen energy is realized. A green route for converting biomass energy into hydrogen energy is provided, and through comparative analysis of a hydrogen production energy source and a hydrogen production scheme, external gas purchase is reduced, and the carbon emission of converting biomass into heat energy is reduced. And multi-element utilization of hydrogen energy is realized. And absorption of wind and light new energy is promoted. And a stepped carbon transaction mechanism is introduced.

Description

Technical Field

[0001] The present invention relates to the technical field of energy management, and specifically to an optimization scheduling method for an integrated energy system taking into account biogas reforming to produce hydrogen and fuel gas blending with hydrogen. Background Art

[0002] At present, the mainstream hydrogen production method in my country is natural gas production, which has the advantages of good economy and low carbon emissions, but the shortage of natural gas supply has limited the further development of this method. At the same time, a large number of biomass waste resources such as straw have not been developed and utilized. Existing studies mostly use biomass gas turbines directly. For example, "Two-stage Optimal Operation of Township Biomass Energy Integrated Energy System Considering Heat Network Loss" analyzes the application benefits of biomass gas turbines in township integrated energy systems, but the problems of high carbon emissions and low energy utilization efficiency of direct combustion of biomass fuels still need to be improved.

[0003] In terms of the multiple utilization of hydrogen energy, the existing technology focuses on hydrogen fuel cells as a single hydrogen user. For example, Chinese patent document CN113098036B records the scheduling method of hydrogen fuel cells participating in the integrated energy system. However, hydrogen fuel cells have the problem of waste heat waste in actual use, and it is necessary to consider the expensive waste heat recovery technology to achieve higher efficiency. Therefore, studying the optimization scheduling method of the integrated energy system of biogas reforming hydrogen production and gas blending hydrogen is of great significance to improve the utilization rate of biomass energy and hydrogen energy, realize the conversion of biomass energy to green hydrogen energy, and accelerate the realization of the dual carbon goals. Summary of the invention

[0004] The present invention provides an optimization scheduling method for an integrated energy system taking into account biogas reforming hydrogen production and fuel gas hydrogen blending, constructs a biogas reforming hydrogen production model and a water electrolysis hydrogen production model for joint hydrogen supply, ensures a reliable supply of natural gas and realizes gas-electricity joint hydrogen production; the generated hydrogen is blended into a gas turbine in a fixed proportion to achieve economical and low-carbon combustion; introduces a step-by-step carbon trading mechanism to analyze the impact of changes in carbon trading parameters on the total cost and carbon emissions of the model; takes the lowest daily operating total cost as the objective function, establishes a low-carbon economic scheduling model for the integrated energy system, and verifies the economic and low-carbon benefits of the proposed model through example simulation.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] The optimization scheduling method of the integrated energy system considering biogas reforming hydrogen production and fuel gas hydrogen blending includes the following steps:

[0007] S1. According to the process flow of biogas reforming hydrogen production, establish a comprehensive energy system structure including biogas reforming hydrogen production and fuel gas hydrogen blending;

[0008] S2. Establish biogas reforming hydrogen production, hydrogen-blended gas turbines, and tiered carbon trading models;

[0009] S3. Under the premise of meeting power balance and equipment constraints, establish an optimization scheduling model for the comprehensive energy system including biogas reforming and hydrogen production;

[0010] S4. Obtain system wind and solar power output, load, and time-of-use electricity price data;

[0011] S5. Solve the scheduling model in S3, verify the economy and low carbon nature of the biogas reforming hydrogen production method, and analyze the benefits of hydrogen-blended combustion.

[0012] The above-mentioned S1 has a comprehensive energy system structure that includes biogas reforming hydrogen production and fuel gas blending with hydrogen. The energy sources of the system include wind power, photovoltaics, biomass biogas, purchased electricity, and purchased gas; the conversion equipment includes electrolyzers, gas turbines, hydrogen fuel cells, and electric boilers; the energy storage equipment includes electricity storage, heat storage, and hydrogen storage; the biogas reforming hydrogen production equipment includes biogas pressure swing adsorption purification equipment and steam methane reforming hydrogen production equipment.

[0013] The establishment process of the biogas reforming hydrogen production model in S2 is as follows:

[0014] The biogas produced by PSA is supplied together with the purchased natural gas, and the separated and purified carbon dioxide is stored on site; the biogas PSA purification model is as follows:

[0015]

[0016] Where: is the biogas production in period t, η MG is the straw utilization rate, E MG is the gas-producing factor, is the mass of biomass straw used in period t; is the biogas production in period t, is the CH4 production coefficient, is the percentage content of CH4 in biogas; is the amount of CO2 stored in period t, is the CO2 emission in period t, is the ratio of CO2 to CH4 content in biogas, is the carbon dioxide loss coefficient, δ is the CO2 volume conversion coefficient; is the power consumption during period t, is the power consumption coefficient of the pressure swing adsorption equipment; The upper limit of biogas production; It is the upper and lower limits of the ramp of the pressure swing adsorption equipment;

[0017] The natural gas required for steam methane reforming hydrogen production is met by biogas and purchased natural gas; the steam methane reforming hydrogen production model is as follows:

[0018]

[0019] Where: is the hydrogen production in period t, is the gas-to-hydrogen efficiency of the steam methane reforming equipment, q G The low calorific value of natural gas. The low calorific value of hydrogen. is the gas consumption during period t; is the power consumption during period t, is the power consumption coefficient of the steam methane reforming equipment; is the CO2 emission in period t; is the carbon emission coefficient of the steam methane reforming equipment; It is the upper limit of hydrogen production of steam methane reforming equipment.

[0020] The process of establishing the hydrogen-blended gas turbine model in the above S2 is as follows:

[0021] The hydrogen-blended gas turbine model is as follows:

[0022]

[0023] Where: is the electrical and thermal power output of the gas turbine during period t, is the volume of natural gas and hydrogen consumed by the gas turbine during period t, Output electrical and thermal efficiency for gas turbines; is the hydrogen blending ratio of the gas turbine; Provides an upper limit on the electrical power output of the gas turbine; The upper and lower limits of the gas turbine climbing power.

[0024] The process of establishing the above-mentioned S2 mid-tier carbon trading model is as follows:

[0025] The ladder carbon trading includes two parts: carbon trading quota and carbon emissions. The calculation formula of carbon trading quota and carbon emissions is as follows:

[0026]

[0027] Where: is the carbon trading quota and carbon emissions in period t, is the actual carbon emissions participating in carbon trading during period t, The carbon emission quota and carbon emission per unit of electricity purchased. The carbon emission quota and carbon emission per unit of power generated by hydrogen-blended gas turbines are: The carbon emission quota and carbon emission per unit heat output of hydrogen-blended gas turbine;

[0028] The calculation formula of the ladder carbon trading mechanism is as follows:

[0029]

[0030] Where: is the step carbon trading cost in period t, χ is the benchmark value, l is the interval length, and θ is the price growth rate.

[0031] The establishment process of the optimization scheduling model of the integrated energy system containing biogas reforming hydrogen production in the above S3 is as follows:

[0032] Objective Function

[0033] The comprehensive energy system model of biogas reforming hydrogen production and gas blending hydrogen has the lowest total cost under the premise of meeting power balance and equipment constraints; the objective function is as follows:

[0034] minC=C WA +C BUY +C JG +C CT +C C +C O ;

[0035] Where: C is the total daily operating cost of the integrated energy system including biogas reforming hydrogen production; C WA Cost of abandoned wind and solar power; C BUY C is the energy purchase cost; JG is the cost of straw; C CT is the carbon trading cost; C C is the carbon storage cost of the pressure swing adsorption equipment; C O is the operation and maintenance cost of each unit; the expressions of each item are:

[0036]

[0037] Where: is the abandoned wind power and photovoltaic power in period t, p WA 、p VA The unit price for abandoned wind power and photovoltaic power; is the power of electricity and gas purchased during period t, is the time-of-use electricity and gas price; JG is the price of straw, 350 yuan / t; p C is the unit price of carbon storage, which is 30 yuan / t; i∈{CHP,EB,SMR,ET,HFC,PSA,ES,TS,HS,W,V}, is the output power of device i in period t, p i The unit price of operation and maintenance of equipment i.

[0038] The constraints of the optimization scheduling model of the integrated energy system containing biogas reforming hydrogen production in S3 are as follows:

[0039] Electricity, heat, hydrogen and gas power balance:

[0040]

[0041] Where: is the online power of wind power and photovoltaic units during period t; is the electricity, heat and natural gas load of the system during period t; is the electricity and heat power generated by the hydrogen fuel cell equipment during period t, is the volume of hydrogen consumed by the hydrogen fuel cell device during period t; The power consumption and heat generation of the electric boiler equipment in time period t; is the power consumption of the water electrolysis equipment during period t, is the hydrogen production of the water electrolysis equipment in period t; is the charging and discharging power of the electricity and heat storage equipment in period t, is the charging and discharging power of the heat storage device in period t, The hydrogen storage device is the volume of hydrogen absorbed and released during period t; energy storage model constraints:

[0042]

[0043] Where: is the capacity of the energy storage device in period t, The upper and lower limits of the energy storage device capacity; The upper and lower limits of charging and discharging power for electricity and heat storage equipment, and the upper and lower limits of absorbing and releasing hydrogen volume for hydrogen storage equipment; The capacity of the energy storage device at the beginning and end of the period;

[0044] Wind and solar power unit output constraints:

[0045]

[0046] Where: is the electrical output power of wind turbines and photovoltaic units during period t.

[0047] The present invention provides an optimization scheduling method for an integrated energy system that takes into account biogas reforming hydrogen production and fuel gas hydrogen blending. First, a biogas reforming hydrogen production model is constructed to achieve biogas hydrogen production while meeting the natural gas load. Secondly, the hydrogen produced by water electrolysis and biogas reforming is combined to explore the impact of biogas reforming hydrogen production on the economy and low carbon of the system. Then, the generated hydrogen is supplied to hydrogen fuel cells and hydrogen-blended gas turbines, and a step-by-step carbon trading mechanism is introduced to limit the carbon emissions of the system. Finally, with the lowest total daily operating cost as the objective function, four different scenarios are set for simulation analysis. It has the following beneficial effects:

[0048] 1) Realize the diversified production of hydrogen energy. A green route for the conversion of biomass energy to hydrogen energy is proposed. By comparing and analyzing the energy source and hydrogen production scheme of hydrogen production, the external gas purchase is reduced and the carbon emissions from the conversion of biomass to thermal energy are reduced. The biogas reforming hydrogen production scheme is applied to the integrated energy system, which can further realize the system optimization and scheduling.

[0049] 2) Realize the diversified utilization of hydrogen energy. The hydrogen produced by water electrolysis is supplied to hydrogen fuel cells and gas turbines to realize the conversion of hydrogen energy into electricity and heat energy. The addition of hydrogen to gas turbines in a certain proportion can further reduce the use of natural gas. At the same time, the use of hydrogen can promote the system to absorb more wind and solar energy.

[0050] 3) It promotes the consumption of wind and solar energy. With the increase of hydrogen blending ratio in gas turbines, the use of hydrogen is promoted. The increase of hydrogen production by water electrolysis reduces the amount of wind and solar power abandoned. Compared with a single hydrogen source, the application of biogas reforming hydrogen production method improves the flexibility of system scheduling.

[0051] 4) The introduction of a step-by-step carbon trading mechanism further limits the carbon emissions generated during the biomass utilization process. Step-by-step carbon trading includes two parts: carbon trading quotas and carbon emissions. The carbon emissions generated during the entire biomass utilization process are considered to form actual carbon emissions. Different carbon emissions are in different ranges, resulting in different carbon trading costs, limiting actual carbon emissions and achieving green and low-carbon use of biomass. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0053] Figure 1 This is a schematic diagram of the process of producing hydrogen from biogas reforming according to the present invention;

[0054] Figure 2 It is a schematic diagram of the structure of the comprehensive energy system for producing hydrogen by reforming biogas according to the present invention;

[0055] Figure 3 It is a schematic diagram of wind power and photovoltaic output;

[0056] Figure 4 It is a schematic diagram of the power of electricity, heat and gas loads;

[0057] Figure 5 It is a schematic diagram of electric power dispatch;

[0058] Figure 6 is a schematic diagram of thermal power scheduling;

[0059] Figure 7 It is a schematic diagram of hydrogen dispatch;

[0060] Figure 8 It is a schematic diagram of natural gas scheduling;

[0061] Fig. 9 This is a schematic diagram of total cost and carbon emissions under different hydrogen blending ratios. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following content will systematically and completely describe the specific technical solutions of the present invention in combination with the drawings provided according to the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0063] Embodiment 1:

[0064] The optimization scheduling method of the integrated energy system considering biogas reforming hydrogen production and fuel gas hydrogen blending includes the following steps:

[0065] S1. According to the process flow of biogas reforming hydrogen production, establish a comprehensive energy system structure including biogas reforming hydrogen production and fuel gas hydrogen blending;

[0066] S2. Establish biogas reforming hydrogen production, hydrogen-blended gas turbines, and tiered carbon trading models;

[0067] S3. Under the premise of meeting power balance and equipment constraints, establish an optimization scheduling model for the comprehensive energy system including biogas reforming and hydrogen production;

[0068] S4. Obtain system wind and solar power output, load, and time-of-use electricity price data;

[0069] S5. Solve the scheduling model in S3, verify the economy and low carbon nature of the biogas reforming hydrogen production method, and analyze the benefits of hydrogen-blended combustion.

[0070] Biogas reforming hydrogen production process

[0071] Biogas reforming hydrogen production process includes three steps: anaerobic fermentation to produce biogas, biogas pressure swing adsorption purification and steam methane reforming to produce hydrogen. The process flow is as follows: Figure 1 As shown:

[0072] Anaerobic fermentation is a common method for biogas production. The generated syngas usually contains 55% methane and 45% carbon dioxide. Pressure swing adsorption is an important way to purify biogas. Compared with ordinary pressure swing adsorption devices, second-order pressure swing adsorption can increase the purity of carbon dioxide and methane produced to more than 99%. High-purity methane is purified by steam methane reforming to produce hydrogen with a purity of up to 99%.

[0073] Integrated energy system structure including biogas reforming to produce hydrogen

[0074] The comprehensive energy system structure includes biogas reforming to produce hydrogen and gas blending with hydrogen. The energy sources of the system include wind power, photovoltaics, biomass biogas, electricity purchase, and gas purchase; the conversion equipment includes electrolyzers, gas turbines, hydrogen fuel cells, and electric boilers; the energy storage equipment includes electricity storage, heat storage, and hydrogen storage; the biogas reforming hydrogen production equipment includes biogas pressure swing adsorption purification equipment and steam methane reforming hydrogen production equipment.

[0075] How it works

[0076] Biogas reforming hydrogen production model

[0077] The biogas produced by PSA is supplied together with the purchased natural gas, and the separated and purified carbon dioxide is stored on site; the biogas PSA purification model is as follows:

[0078]

[0079] Where: is the biogas production in period t, η MG is the straw utilization rate, E MG is the gas-producing factor, is the mass of biomass straw used in period t; is the biogas production in period t, is the CH4 production coefficient, is the percentage content of CH4 in biogas; is the amount of CO2 stored in period t, is the CO2 emission in period t, is the ratio of CO2 to CH4 content in biogas, is the carbon dioxide loss coefficient, δ is the CO2 volume conversion coefficient; is the power consumption during period t, is the power consumption coefficient of the pressure swing adsorption equipment; The upper limit of biogas production; It is the upper and lower limits of the ramp of the pressure swing adsorption equipment;

[0080] The natural gas required for steam methane reforming hydrogen production is met by biogas and purchased natural gas; the steam methane reforming hydrogen production model is as follows:

[0081]

[0082] Where: is the hydrogen production in period t, is the gas-to-hydrogen efficiency of the steam methane reforming equipment, q G The low calorific value of natural gas. The low calorific value of hydrogen. is the gas consumption during period t; is the power consumption during period t, is the power consumption coefficient of the steam methane reforming equipment; is the CO2 emission in period t; is the carbon emission coefficient of the steam methane reforming equipment; It is the upper limit of hydrogen production of steam methane reforming equipment.

[0083] Gas Turbine Hydrogen Blending Model

[0084] In order to further reduce the carbon emissions of the system, this paper adopts a hydrogen-blended gas turbine to achieve low-carbon combustion of natural gas; research shows that the gas turbine can operate safely and stably when the hydrogen blending ratio is within 20%; the hydrogen-blended gas turbine model is as follows:

[0085]

[0086] Where: is the electrical and thermal power output of the gas turbine during period t, is the volume of natural gas and hydrogen consumed by the gas turbine during period t, Output electrical and thermal efficiency for gas turbines; is the hydrogen blending ratio of the gas turbine; Provides an upper limit on the electrical power output of the gas turbine; The upper and lower limits of the gas turbine climbing power.

[0087] Ladder Carbon Trading Model

[0088] The ladder carbon trading includes two parts: carbon trading quota and carbon emissions. The calculation formula of carbon trading quota and carbon emissions is as follows:

[0089]

[0090] Where: is the carbon trading quota and carbon emissions in period t, Q t b is the actual carbon emissions participating in carbon trading during period t, The carbon emission quota and carbon emission per unit of electricity purchased. The carbon emission quota and carbon emission per unit of power generated by hydrogen-blended gas turbines are: The carbon emission quota and carbon emission per unit heat output of hydrogen-blended gas turbine;

[0091] The ladder carbon trading mechanism divides the difference between actual carbon emissions and carbon trading quotas into multiple price ranges. Compared with ordinary carbon trading, it has a more obvious effect on limiting carbon emissions. The calculation formula is as follows:

[0092]

[0093] Where: is the step carbon trading cost in period t, χ is the benchmark value, l is the interval length, and θ is the price growth rate.

[0094] Optimal scheduling model for integrated energy system including biogas reforming for hydrogen production

[0095] Objective Function

[0096] The proposed integrated energy system model of biogas reforming hydrogen production and gas blending hydrogen has the lowest total cost under the premise of meeting power balance and equipment constraints; the objective function is as follows:

[0097] minC=C WA +C BUY +C JG +C CT +C C +C O ;

[0098] Where: C is the total daily operating cost of the integrated energy system including biogas reforming hydrogen production; C WA Cost of abandoned wind and solar power; C BUY C is the energy purchase cost; JG is the cost of straw; C CT is the carbon trading cost; C C is the carbon storage cost of the pressure swing adsorption equipment; C O is the operation and maintenance cost of each unit; the expressions of each item are:

[0099]

[0100] Where: is the abandoned wind power and photovoltaic power in period t, p WA 、p VA The unit price for abandoned wind power and photovoltaic power; is the power of electricity and gas purchased during period t, is the time-of-use electricity and gas price; JG is the price of straw, 350 yuan / t; p C is the unit price of carbon storage, which is 30 yuan / t; i∈{CHP,EB,SMR,ET,HFC,PSA,ES,TS,HS,W,V}, is the output power of device i in period t, p i The unit price of operation and maintenance of equipment i.

[0101] The constraints are:

[0102] Electricity, heat, hydrogen and gas power balance:

[0103]

[0104] Where: is the online power of wind power and photovoltaic units during period t; is the electricity, heat and natural gas load of the system during period t; is the electricity and heat power generated by the hydrogen fuel cell equipment during period t, is the volume of hydrogen consumed by the hydrogen fuel cell device during period t; The power consumption and heat generation of the electric boiler equipment in time period t; is the power consumption of the water electrolysis equipment during period t, is the hydrogen production of the water electrolysis equipment in period t; is the charging and discharging power of the electricity and heat storage equipment in period t, is the charging and discharging power of the heat storage device in period t, The hydrogen storage device is the volume of hydrogen absorbed and released during period t; energy storage model constraints:

[0105]

[0106] Where: is the capacity of the energy storage device in period t, The upper and lower limits of the energy storage device capacity; The upper and lower limits of charging and discharging power for electricity and heat storage equipment, and the upper and lower limits of absorbing and releasing hydrogen volume for hydrogen storage equipment; The capacity of the energy storage device at the beginning and end of the period;

[0107] Wind and solar power unit output constraints:

[0108]

[0109] Where: is the electrical output power of wind turbines and photovoltaic units during period t.

[0110] Model solving and simulation analysis

[0111] The low-carbon economic dispatch model of the integrated energy system of biogas reforming hydrogen production and gas blending hydrogen is a mixed integer linear programming problem, which is solved by calling the GUROBI solver of the MATLAB platform. Figure 3 , electricity, heat and gas loads see Figure 4 The time-of-use electricity price and gas price are shown in Table 1. The parameters of the biogas PSA purification and SMR hydrogen production model are shown in Table 2. The unit price of wind and solar power abandonment is 400 yuan / MWh; the benchmark value in the ladder carbon trading model is 200 yuan / t, the interval length is 10t, and the price growth rate is 0.3; the operation and maintenance of SMR hydrogen production is 0.623 yuan / m 3 .

[0112] Simulation Results Analysis

[0113] In order to verify the economy and low carbon nature of the biogas reforming hydrogen production model, four sets of operation scenarios were constructed.

[0114] Scenario 1: All natural gas is supplied by purchased gas, and hydrogen is produced only by electrolysis of water.

[0115] Scenario 2: All natural gas is supplied by purchased gas, and hydrogen is produced by a combination of water electrolysis and steam methane reforming.

[0116] Scenario 3: Natural gas is supplied by a combination of biomass supply and purchased gas, and hydrogen is produced only through water electrolysis.

[0117] Scenario 4: Natural gas is supplied by a combination of biomass supply and purchased gas, and hydrogen is produced by a combination of water electrolysis and steam methane reforming.

[0118] The scheduling results of the four scenarios are shown in Table 3. As can be seen from the table, the total cost of scenario 2 is 2.53% lower than that of scenario 1, and the carbon emissions are reduced by 12.09%. Compared with scenario 1, which only produces hydrogen through water electrolysis, steam methane reforming can broaden the source of hydrogen for the system and realize the combined production of hydrogen by gas and electricity, but the amount of natural gas required increases and the cost of purchasing gas increases. The diversity of hydrogen production methods reduces the amount of electricity purchased from outside, reduces the cost of purchasing electricity, reduces the carbon emissions caused by purchasing electricity, and reduces the cost of carbon trading.

[0119] Scenario 3 reduces the total cost by 3.21% and increases carbon emissions by 1.76% compared to Scenario 1. Scenario 3 uses biogas produced by biomass biogas purification as another source of natural gas. Compared with purchasing natural gas separately, it can reduce the cost of purchasing gas and promote the utilization of biomass energy. However, the biogas purification process will increase power consumption, increase the cost of purchasing electricity and the output of gas turbine units, and increase carbon emissions.

[0120] Scenario 4 reduces the total cost by 5.33% and the carbon emissions by 5.17% compared with Scenario 1. Scenario 4 reduces the cost of electricity and gas purchases through biogas reforming hydrogen production, but increases the operation and maintenance costs and biomass raw material costs. At the same time, the biogas reforming hydrogen production process will produce a certain amount of carbon emissions. Since its carbon emission quota is not currently defined, the carbon trading cost of Scenario 4 is higher than that of Scenario 1. From the above analysis, it can be seen that compared with hydrogen production by electrolysis of water alone, biogas reforming hydrogen production can improve the flexibility of energy purchase scheduling and achieve a reduction in total cost and carbon emissions.

[0121] Scheduling results analysis

[0122] Figure 5-8 The following are the dispatch results of electricity, thermal power, hydrogen and natural gas for scenario 4. Figure 5It can be seen that during the high-output period of wind and solar power (1:00-5:00, 10:00-15:00, 22:00-24:00), the wind and solar energy are consumed through the process of hydrogen production by electrolysis of water, biogas pressure swing adsorption purification and steam methane reforming hydrogen production, and the excess electricity is stored by power storage equipment and converted by electric boilers to meet the system power balance. During the low output period of wind and solar power (6:00-9:00, 17:00-21:00), the power is discharged by power storage equipment and the shortfall is directly purchased. During the period of low electricity price (6:00), the cost of hydrogen production by electrolysis of water is lower than that of hydrogen production by steam methane reforming, so electricity purchase is chosen to produce hydrogen. During the period of high electricity price (19:00-21:00), the cost of producing biogas is low, so biogas reforming is chosen to produce hydrogen. The above analysis shows that the biogas reforming hydrogen production model has good economic efficiency in hydrogen production.

[0123] Depend on Figure 6 It can be seen that the heat load is supplied by the gas turbine, electric boiler equipment and hydrogen fuel cell equipment, and the shortfall or surplus is met by the heat storage equipment. The electric boiler equipment decouples the gas turbine from heat and electricity, and the use of hydrogen fuel cell equipment realizes the conversion of hydrogen energy into heat energy.

[0124] Depend on Figure 7 It can be seen that during the period of high electricity prices (7:00-9:00, 16:00-21:00), when water electrolysis cannot meet the hydrogen demand, it is cheaper to choose steam methane reforming to produce hydrogen. The supplied hydrogen will first meet the needs of gas turbines, and the surplus will be consumed by hydrogen fuel cell equipment and hydrogen storage equipment.

[0125] Depend on Figure 8 It can be seen that during the period of high wind and solar output, biogas production is chosen to consume wind and solar power. When the biogas output reaches the upper limit, natural gas is purchased to make up for the shortfall. During the periods (6:00, 9:00, 16:00, and 19:00), in order to meet the pressure swing adsorption ramp power constraint, a certain amount of biogas is chosen to be prepared. During the period of high natural gas prices (20:00-21:00), biogas is chosen to achieve economical gas use, and the shortfall is met by purchasing gas. During the period of low natural gas prices (7:00-8:00, 17:00-18:00), it is more economical to purchase natural gas directly.

[0126] 6.4 Hydrogen-blended combustion analysis

[0127] The combustion of hydrogen in gas turbines can reduce natural gas consumption and achieve multiple uses of hydrogen, but excessive hydrogen demand will increase the burden of hydrogen production in the system. Therefore, it is necessary to conduct a sensitivity analysis on the hydrogen blending ratio of gas turbines to obtain the changes in total cost, carbon emissions, and hydrogen production from steam methane reforming, such as Fig. 9 shown.

[0128] Depend on Fig. 9It can be seen that with the increase of the hydrogen blending ratio of the gas turbine, the total cost and carbon emissions first decrease and then increase, and the amount of hydrogen produced by natural gas continues to increase. Compared with the case of no hydrogen blending, the moderate hydrogen blending combustion of the gas turbine can promote the increase of hydrogen production by water electrolysis and steam methane reforming, while reducing the amount of natural gas required by the gas turbine in each period, and realizing economic and low-carbon operation. The increase in hydrogen production by water electrolysis can promote the consumption of wind and solar power, thereby reducing the cost of abandoning wind and solar power; the increase in hydrogen production by steam methane reforming can reduce carbon emissions and energy purchase costs caused by excessive power purchase in the system; the reduction in natural gas demand reduces the use of biogas, carbon emissions and straw costs. When the hydrogen blending ratio exceeds 0.1, the demand for hydrogen exceeds the maximum supply. At this time, the energy source required for hydrogen production is met by purchasing electricity and gas, so the total cost and carbon emissions increase. From the above analysis, it can be seen that moderate hydrogen blending of gas turbines can promote the consumption of wind and solar power and reduce energy purchase costs; but excessive hydrogen blending will increase energy purchase costs and carbon emissions, which is not conducive to economic and low-carbon operation of the system.

Claims

1. An optimization scheduling method for an integrated energy system considering biogas reforming to produce hydrogen and fuel gas blending with hydrogen, characterized in that: The following steps are involved: S1. According to the process flow of biogas reforming hydrogen production, establish a comprehensive energy system structure including biogas reforming hydrogen production and fuel gas hydrogen blending; S2. Establish biogas reforming hydrogen production, hydrogen-blended gas turbines, and tiered carbon trading models; S3. Under the premise of meeting power balance and equipment constraints, establish an optimization scheduling model for the comprehensive energy system including biogas reforming and hydrogen production; S4. Obtain system wind and solar power output, load, and time-of-use electricity price data; S5. Solve the scheduling model in S3, verify the economy and low carbon nature of the biogas reforming hydrogen production method, and analyze the benefits of hydrogen-blended combustion.

2. The method for optimizing the scheduling of an integrated energy system considering biogas reforming hydrogen production and fuel gas hydrogen blending according to claim 1, characterized in that: The S1 contains a comprehensive energy system structure of biogas reforming hydrogen production and fuel gas blending hydrogen. The energy sources of the system include wind power, photovoltaics, biomass biogas, purchased electricity, and purchased gas; the conversion equipment includes electrolyzers, gas turbines, hydrogen fuel cells, and electric boilers; the energy storage equipment includes electricity storage, heat storage, and hydrogen storage; the biogas reforming hydrogen production equipment includes biogas pressure swing adsorption purification equipment and steam methane reforming hydrogen production equipment.

3. The method for optimizing the scheduling of an integrated energy system considering biogas reforming hydrogen production and fuel gas hydrogen blending according to claim 1, characterized in that: The process of establishing the biogas reforming hydrogen production model in S2 is as follows: The biogas produced by PSA is supplied together with the purchased natural gas, and the separated and purified carbon dioxide is stored on site; the biogas PSA purification model is as follows: Where: is the biogas production in period t, η MG is the straw utilization rate, E MG is the gas-producing factor, is the mass of biomass straw used in period t; is the biogas production in period t, is the CH4 production coefficient, is the percentage content of CH4 in biogas; is the amount of CO2 stored in period t, is the CO2 emission in period t, is the ratio of CO2 to CH4 content in biogas, is the carbon dioxide loss coefficient, δ is the CO2 volume conversion coefficient; P t PSA is the power consumption during period t, is the power consumption coefficient of the pressure swing adsorption equipment; The upper limit of biogas production; It is the upper and lower limits of the ramp of the pressure swing adsorption equipment; The natural gas required for steam methane reforming hydrogen production is met by biogas and purchased natural gas; the steam methane reforming hydrogen production model is as follows: Where: V t SMR is the hydrogen production in period t, is the gas-to-hydrogen efficiency of the steam methane reforming unit, q G The low calorific value of natural gas. The low calorific value of hydrogen. is the gas consumption during period t; P t SMR is the power consumption during period t, is the power consumption coefficient of the steam methane reforming equipment; is the CO2 emission in period t; is the carbon emission coefficient of the steam methane reforming equipment; It is the upper limit of hydrogen production of steam methane reforming equipment.

4. The method for optimizing the scheduling of an integrated energy system considering biogas reforming hydrogen production and fuel gas hydrogen blending according to claim 2, characterized in that: The process of establishing the hydrogen-blended gas turbine model in S2 is as follows: The hydrogen-blended gas turbine model is as follows: Where: P t CHP , is the electrical and thermal power output of the gas turbine during period t, is the volume of natural gas and hydrogen consumed by the gas turbine during period t, Y is the electrical and thermal efficiency of the gas turbine output; t CHP is the hydrogen blending ratio of the gas turbine; Provides an upper limit on the electrical power output of the gas turbine; The upper and lower limits of the gas turbine climbing power.

5. The method for optimizing the scheduling of an integrated energy system considering biogas reforming hydrogen production and fuel gas hydrogen blending according to claim 4, characterized in that: The process of establishing the S2 medium-tier carbon trading model is as follows: The ladder carbon trading includes two parts: carbon trading quota and carbon emissions. The calculation formula of carbon trading quota and carbon emissions is as follows: Where: is the carbon trading quota and carbon emissions in period t, is the actual carbon emissions participating in carbon trading during period t, The carbon emission quota and carbon emission per unit of electricity purchased. The carbon emission quota and carbon emission per unit of power generated by hydrogen-blended gas turbines are: The carbon emission quota and carbon emission per unit heat output of hydrogen-blended gas turbine; The calculation formula of the ladder carbon trading mechanism is as follows: Where: is the step carbon trading cost in period t, χ is the benchmark value, l is the interval length, and θ is the price growth rate.

6. The method for optimizing the scheduling of an integrated energy system considering biogas reforming hydrogen production and fuel gas hydrogen blending according to claim 5, characterized in that: The process of establishing the optimization scheduling model of the comprehensive energy system containing biogas reforming hydrogen production in S3 is as follows: Objective Function The comprehensive energy system model of biogas reforming hydrogen production and gas blending hydrogen has the lowest total cost under the premise of meeting power balance and equipment constraints; the objective function is as follows: minC=C WA +C BUY +C JG +C CT +C C +C O ; Where: C is the total daily operating cost of the integrated energy system including biogas reforming hydrogen production; C WA Cost of abandoned wind and solar power; C BUY C is the energy purchase cost; JG is the cost of straw; C CT is the carbon trading cost; C C is the carbon storage cost of the pressure swing adsorption equipment; C O is the operation and maintenance cost of each unit; the expressions of each item are: Where: P t WA , P t VA is the abandoned wind power and photovoltaic power in period t, p WA 、p VA is the unit price of abandoned wind power and photovoltaic power; P t BUY , G t BUY is the power of electricity and gas purchased during period t, is the time-of-use electricity and gas price; JG is the price of straw, 350 yuan / t; p C is the unit price of carbon storage, which is 30 yuan / t; i∈{CHP,EB,SMR,ET,HFC,PSA,ES,TS,HS,W,V}, P t i is the output power of device i in period t, p i The unit price of operation and maintenance of equipment i.

7. The method for optimizing the scheduling of an integrated energy system considering biogas reforming hydrogen production and fuel gas hydrogen blending according to claim 6, characterized in that: The constraints of the optimization scheduling model of the comprehensive energy system containing biogas reforming hydrogen production in S3 are: Electricity, heat, hydrogen and gas power balance: Where: P t WN , P t VN P is the on-grid power of wind power and photovoltaic units in period t; t E , P is the electricity, heat and natural gas load of the system during period t; t HFC , is the electricity and heat power generated by the hydrogen fuel cell equipment during period t, V t HFC P is the volume of hydrogen consumed by the hydrogen fuel cell device during period t; t EB , P is the power consumption and heat generation of the electric boiler equipment in period t; t ET is the power consumption of the water electrolysis equipment during period t, V t ET is the hydrogen production of the water electrolysis equipment in period t; P t ES,cha , P t ES,dis is the charging and discharging power of the electricity and heat storage equipment in period t, P t TS,cha , P t TS,dis is the charging and discharging power of the heat storage device in period t, P t HS,cha , P t HS ,dis The hydrogen storage equipment is the volume of hydrogen absorbed and released during period t; Energy storage model constraints: Where: is the capacity of the energy storage device in period t, The upper and lower limits of the energy storage device capacity; The upper and lower limits of charging and discharging power for electricity and heat storage equipment, and the upper and lower limits of absorbing and releasing hydrogen volume for hydrogen storage equipment; The capacity of the energy storage device at the beginning and end of the period; Wind and solar power unit output constraints: Where: P t W , P t V is the electrical output power of wind turbines and photovoltaic units during period t.

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