Electricity-hydrogen coupling system low-carbon scheduling method considering low-carbon regulation and control capability of virtual energy pool in green hydrogen chemical industry

Abstract

The invention discloses an electricity-hydrogen coupling system low-carbon scheduling method considering the low-carbon regulation and control capability of a green-hydrogen chemical virtual energy pool, and the method comprises the following steps: 1) constructing a fixed-carbon emission operation domain of the green-hydrogen chemical virtual energy pool, and carrying out the quantification of the low-carbon regulation and control capability of the green-hydrogen chemical virtual energy pool; 2) constructing a green hydrogen chemical industry virtual energy pool carbon emission determination operation domain boundary analytical expression; 3) constructing an electricity-hydrogen coupling system low-carbon scheduling model considering the low-carbon regulation and control capability of the virtual energy pool in the green hydrogen chemical industry based on a carbon emission operation domain boundary analytical expression in the virtual energy pool in the green hydrogen chemical industry; and 4) realizing scheduling of the electricity-hydrogen coupling system by using the electricity-hydrogen coupling system low-carbon scheduling model. According to the invention, the new energy consumption level of the electricity-hydrogen coupling system can be effectively improved, and the operation economy of the system is improved.

Description

Technical Field

[0001] The present invention relates to the field of optimal operation of the electricity-hydrogen coupling system, and specifically to a low-carbon scheduling method for the electricity-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool. Background Art

[0002] Using excess new energy sources such as wind and light to produce green hydrogen and further synthesize chemical products such as ammonia, methanol, and methane is an important path to achieve large-scale consumption of new energy and promote the low-carbon transformation of the entire industry. As an emerging power flexibility resource, green hydrogen chemical industry's flexible regulation ability and low-carbon scheduling potential can contribute to the deep decarbonization of the power industry.

[0003] However, the research on the green hydrogen chemical industry is currently in its infancy, and this industry involves information intersection of multiple industries such as power and chemical industries. The coupled operation problems of power, green hydrogen, and its downstream chemical industries need to be further studied. When the green hydrogen chemical virtual energy pool at the distribution network or microgrid level operates in coordination with the large-scale electricity-hydrogen coupling system, the traditional method is to treat it as a fixed load, and the large-scale electricity-hydrogen coupling system formulates a scheduling plan based on the determined information provided by the green hydrogen chemical virtual energy pool; and conventional system operators avoid submitting internal system information to protect the privacy information of users, which brings certain difficulties to the coordinated operation. Moreover, the green hydrogen chemical virtual energy pool has diverse and flexible regulation capabilities such as production, storage, and transportation, and contains distributed resources with spatio-temporal coupling and time-varying resources such as energy storage and long tube trailers, making it difficult to directly determine its operating state. Therefore, the traditional research method has certain drawbacks, and there is an urgent need for a new coordinated scheduling method to solve problems such as information asymmetry between the large-scale electricity-hydrogen coupling system and the green hydrogen chemical virtual energy pool.

[0004] In summary, there is currently a lack of a low-carbon scheduling method for the electricity-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool. Summary of the Invention

[0005] The purpose of the present invention is to provide a low-carbon scheduling method for the electricity-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool, including the following steps:

[0006] 1) Construct a carbon emission fixed operation domain for the green hydrogen chemical virtual energy pool to quantify the low-carbon regulation ability of the green hydrogen chemical virtual energy pool;

[0007] 2) Construct an analytical expression for the boundary of the carbon emission fixed operation domain of the green hydrogen chemical virtual energy pool;

[0008] 3) Based on the analytical expression for the boundary of the carbon emission fixed operation domain of the green hydrogen chemical virtual energy pool, construct a low-carbon scheduling model for the electricity-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool;

[0009] 4) The dispatching of the electricity - hydrogen coupling system is realized by using the low - carbon dispatching model of the electricity - hydrogen coupling system.

[0010] Furthermore, the carbon - emission - fixed operation domain of the green hydrogen chemical virtual energy pool is used to reflect the operation space of the green hydrogen chemical virtual energy pool under the low - carbon and safe operation constraints, that is:

[0011]

[0012] In the formula, is the carbon - emission - fixed operation domain of the q - th green hydrogen chemical virtual energy pool; Q is the total number of green hydrogen chemical virtual energy pools; is the power of the x - th type of load of the q - th green hydrogen chemical virtual energy pool that the power system needs to meet, N q is the total number of loads of the q - th green hydrogen chemical virtual energy pool; h(y q ) = 0 is the equality constraint that the green hydrogen chemical virtual energy pool needs to meet; s(y q ) ≤ 0 is the inequality constraint that the green hydrogen chemical virtual energy pool needs to meet.

[0013] Furthermore, the equality constraints that the green hydrogen chemical virtual energy pool needs to meet include power balance constraints, electricity - hydrogen - chemical coupling operation constraints;

[0014] The inequality constraints that the green hydrogen chemical virtual energy pool needs to meet include the safe operation constraints and carbon - emission constraints of thermal power, new energy, and gas turbine units.

[0015] Furthermore, the green hydrogen chemical virtual energy pool includes an electric - energy subsystem model and a green hydrogen chemical subsystem model;

[0016] Among them, the constraint conditions of the electric - energy subsystem model include thermal power unit output constraints, thermal power unit ramp - up constraints, wind and light output constraints, wind / solar ramp - up constraints, gas turbine operation constraints, system carbon - emission constraints, and power flow constraints;

[0017] The green hydrogen chemical subsystem model includes operation models for hydrogen production, storage, transportation, and utilization links, and the constraint conditions include equipment operation constraints of electrolyzers, hydrogen storage tanks, tube trailers, and fuel cells, and chemical production operation constraints.

[0018] Furthermore, the constraint conditions of the electric - energy subsystem model are shown as follows:

[0019] The thermal power unit output constraints are shown as follows:

[0020]

[0021] In the formula, P k,t is the output of the k - th thermal power unit at time t, and are the lower limit and upper limit of the output of thermal power unit k, respectively.

[0022] The ramp constraints of thermal power units are as follows:

[0023]

[0024] In the formula, RU k and RD k respectively represent the maximum upward and downward ramps of thermal power units. P k,t-1 is the output of the k-th thermal power unit at time t-1;

[0025] The output constraints of new energy units are as follows:

[0026]

[0027] In the formula, and are respectively the lower and upper limits of the output P w,t of wind turbine w; and are respectively the lower and upper limits of the output P s,t of photovoltaic unit s.

[0028] The ramp constraints of new energy units are as follows:

[0029]

[0030] In the formula, P w,t-1 is the output of wind turbine w at time t-1; and are respectively the upper and lower limits of the ramp rate of wind turbine w; P s,t-1 is the output of photovoltaic unit s at time t-1; and are respectively the upper and lower limits of the ramp rate of photovoltaic unit s;

[0031] The operation constraints of gas turbines are as follows:

[0032]

[0033] In the formula, P x,t is the output of the x-th gas turbine at time t, and are respectively the lower and upper limits of the output of the gas turbine; and are respectively the maximum upward ramp rate and the maximum downward ramp rate of the gas turbine. P x,t-1 is the output of the x-th gas turbine at time t-1;

[0034] The system carbon emission constraints are as follows:

[0035]

[0036] In the formula, N k is the total number of thermal power units; T is the scheduling period; e k is the carbon emission intensity of the thermal power unit; N x is the total number of thermal power units; e x is the carbon emission intensity of the gas turbine; Q carbon_emi is the carbon emission limit of the system.

[0037] The electric power balance constraint is as follows:

[0038]

[0039] In the formula, is the total output of the thermal power unit at time t, and are the total outputs of distributed wind and light at time t, is the total output of the gas turbine at time t, is the total output of the hydrogen fuel cell at time t, is the electrical load at time t, is the power consumption of the electrolyzer at time t, is the electrical power consumed by chemical synthesis at time t;

[0040] The power flow constraint is as follows:

[0041]

[0042] In the formula, N is the set of nodes in the system, P i,t and Q i,t are the active injection power and reactive injection power of node i at time t, respectively; G ij and B ij are the real part and imaginary part of the i-th row and j-th column of the node admittance matrix, respectively; U i,t is the voltage amplitude of node i at time t; θ ij,t is the phase angle difference of branch ij at time t; U i,min and U i,max are the lower and upper limits of the node voltage amplitude, respectively. U j,t is the voltage amplitude of node j at time t;

[0043] Furthermore, in the green hydrogen chemical subsystem model, the operation model of the hydrogen production link is as follows:

[0044]

[0045] In the formula, is the electrical power input to hydrogen production station g at time t, is the power consumed by the auxiliary equipment of the hydrogen production station g at time t, α EC is the conversion coefficient between the power consumption and the hydrogen production flow rate, with the unit of MWh / Nm 3 , that is, the power consumption for producing each standard cubic meter of hydrogen is the hydrogen production flow rate of the hydrogen production station g at time t, P EC,min and P EC,max are respectively the lower limit and the upper limit of the input power of the electrolyzer

[0046] The operation model of the hydrogen storage link is as follows

[0047]

[0048] In the formula, C HST is the capacity of the hydrogen storage tank is the energy stored in the hydrogen storage tank of the hydrogen production station g at time t; m and respectively represent the hydrogen storage and hydrogen release flow rates of the hydrogen storage tank in the hydrogen production station g at time t; η HST+ and η HST- respectively represent the hydrogen storage and hydrogen release efficiencies of the hydrogen storage tank is the maximum capacity coefficient of the hydrogen storage tank and respectively represent the upper limits of the hydrogen storage and hydrogen release flow rates of the hydrogen storage tank is the energy stored in the hydrogen storage tank of the hydrogen production station g at time t-1; E HST,0 、 are the initial time, T D the energy stored in the hydrogen storage tank of the hydrogen production station g; Δt is the time step

[0049] The operation model of the hydrogen transportation link is as follows

[0050]

[0051] u c,g,0 =u c,g,T g∈Ω HGS (19)

[0052]

[0053] Q c,min ≤Q c,t ≤Q c,max (22)

[0054]

[0055] In the formula, Ω HT is the set of tube trailers, Ω HGS ={HGS P2A ,HGS P2MeOH ,HGSP2G} is the set of hydrogen production stations, where HGS P2A , HGS P2MeOH , HGS P2G respectively represent the hydrogen production stations of the ammonia synthesis system, the methanol synthesis system, and the methane synthesis system; represents the hydrogen filling flow rate of the tube trailer c at the hydrogen production station g at time t. Q c,t represents the hydrogen storage capacity of the tube trailer c at time t, Q c,t-1 represents the hydrogen storage capacity of the tube trailer c at time t - 1, represents the hydrogen release flow rate of the tube trailer c at the hydrogen production station g at time t; Q c,min and Q c,max respectively represent the lower and upper limits of the hydrogen storage capacity of the tube trailer c; is the state variable of hydrogen filling of the tube trailer c at the hydrogen production station g at time t, 1 represents hydrogen filling, otherwise 0; is the state variable of hydrogen release of the tube trailer c at the hydrogen production station g at time t, 1 represents hydrogen filling, otherwise 0. U c is the position state matrix of the tube trailer c; u c,g,t is a 0 - 1 variable representing the position state of the tube trailer c. When the tube trailer c is at the hydrogen production station g at time t, it is 1, otherwise 0; T D is the scheduling period; G is the total number of hydrogen production stations; is the hydrogen production flow rate of the hydrogen production station; is the upper limit of the hydrogen release flow rate and hydrogen filling flow rate of the tube trailer;

[0056] The operation models of the hydrogen - using links include the P2A system operation model, the methanol synthesis system operation model, the methane synthesis system operation model, and the hydrogen fuel cell model;

[0057] The P2A system operation model is as follows:

[0058]

[0059] N2 + 3H2 2NH3, ΔH=-92.4kJ / mol (27)

[0060]

[0061] t=τ h +8(h - 1) (29)

[0062]

[0063]

[0064] In the formula, is the power consumption of the compressor at time t, is the molar mass of nitrogen, R is the ideal gas constant, T is the compressor temperature, p3 and p1 are the pressures of nitrogen before and after compression respectively, and η is the efficiency of the compressor; h represents the adjustment period of the ammonia synthesis reactor, and the values are 1, 2, 3, is the initial ammonia production flow rate of the ammonia synthesis reactor in the h-th adjustment period, is the adjustment amount in the h-th adjustment period, is τ h the ammonia production flow rate at time, represents the upper limit of the adjustment amount; is the ammonia synthesis rate at time t, and are the lower and upper limits of the ramp rate respectively; and are the lower and upper limits of the ammonia production rate respectively; Equation (27) is the chemical formula of the ammonia synthesis reaction; Equations (28)-(30) are the operation models of the ammonia synthesis reactor adjustment period; Equation (31) is the load ramp rate constraint; Equation (32) is the ammonia synthesis rate constraint; Equations (33)-(34) are the relationship equations between the ammonia production rate and the hydrogen injection flow rate and nitrogen injection flow rate in the ammonia synthesis process; is the ammonia synthesis rate at time t + 1; is the ammonia synthesis rate at time t + 1; ΔT AS is the scheduling period of the ammonia synthesis reactor, is the nitrogen flow rate at time t, λ P2A is the conversion rate of the ammonia synthesis process, is the hydrogen flow rate used for chemical synthesis in hydrogen production station g at time t.

[0065] The operation model of the methanol synthesis system includes the operation models of the electrolytic water hydrogen production, carbon capture section, compression and buffer section, methanol synthesis and rectification section of the methanol synthesis system;

[0066] The operation model of the carbon capture section is as follows:

[0067]

[0068] In the formula, is the energy consumption of the carbon capture device at time t, is the carbon dioxide emitted by the coal-fired power plant used for methanol synthesis at time t, η CCS,t is the carbon capture rate at time t, λ CCS is the energy consumption per unit of CO2 captured, is the carbon capture amount at time t.

[0069] The carbon emission Q of the thermal power unit at time t thermal,t is as follows:

[0070]

[0071] In the formula, N M is the number of thermal power units, and γ n is the carbon emission factor of the nth thermal power unit, with the unit of kgCO2 / kWh. is the power generation of thermal power unit n for methanol synthesis at time t.

[0072] The operation model of the compression and buffering section is as follows:

[0073]

[0074] In the formula, is the electric power consumed by the P2MeOH system for CO2 compression at time t, p4 and p1 are the pressures before and after CO2 compression respectively, is the efficiency of CO2 compression.

[0075] The operation model of the methanol synthesis and rectification section

[0076] CO2 + 3H2 → CH3OH + H2O (39)

[0077]

[0078]

[0079] In the formula, is the methanol production at time t, m MeOH,min and m MeOH,max are the lower and upper limits of the methanol yield respectively. λ P2MeOH is the conversion rate in the methanol synthesis process.

[0080] The operation model of the synthetic methane system includes the operation models of the electrolytic water hydrogen production, carbon capture, compression and buffering, and methanation sections of the synthetic methane system;

[0081] The operation model of the carbon capture section of the synthetic methane system is as follows:

[0082]

[0083] In the formula, is the energy consumption of the carbon capture device of the P2G system at time t, is the carbon dioxide emitted by the coal-fired power plant for synthetic methane at time t, η CCS,t is the carbon capture rate at time t, λ CCS is the energy consumption for capturing unit CO2, is the carbon capture amount for synthetic methane at time t.

[0084] The carbon emission Q of the thermal power unit at time tthermal,t As shown below:

[0085]

[0086] Wherein, N G is the number of thermal power units for carbon capture in the P2G system, and γ z is the carbon emission factor of the z-th thermal power unit, with the unit of kgCO2 / kWh. is the power generation of the z-th thermal power unit for synthesizing methane at time t.

[0087] The operation model of the compression buffer of the methane synthesis system is as follows:

[0088]

[0089] Wherein, is the electric power consumed by the P2G system for compressing CO2 at time t. is the molar mass of CO2;

[0090] The operation model of the methane chemical section is as follows:

[0091] CO2 + 4H2 → CH4 + 2H2O (47)

[0092]

[0093] Wherein, and are respectively the lower limit and the upper limit of the methane production rate . λ P2G is the conversion efficiency of the methanation process.

[0094] The hydrogen fuel cell model is as follows:

[0095]

[0096] Wherein: is the output power of the fuel cell at time t; is the input power of the fuel cell at time t; η EC is the efficiency of the fuel cell. and are respectively the minimum value and the maximum value of the fuel cell power.

[0097] Furthermore, the green hydrogen chemical virtual energy pool needs to satisfy the hydrogen energy balance constraint, that is:

[0098]

[0099] Wherein, is the hydrogen production flow rate at time t, and The hydrogen storage amount and hydrogen release amount at time t, respectively, is the conventional hydrogen load at time t, is the amount of hydrogen used for transportation at time t, is the amount of hydrogen used for chemical synthesis at time t. is the amount of hydrogen consumed by the hydrogen fuel cell.

[0100] Furthermore, the steps to construct the analytical expression for the boundary of the carbon emission fixed operation region of the green hydrogen chemical virtual energy pool include:

[0101] 1) Piecewise linearly fit the two-dimensional carbon emission fixed operation region space of the green hydrogen chemical virtual energy pool to obtain:

[0102]

[0103] In the formula, n is the number of equivalent linear constraints after piecewise linear fitting, P i and P j respectively represent the two-dimensional observation variables of the green hydrogen chemical virtual energy pool, a n , b n and c n are the coefficients of the linear constraint n, respectively.

[0104] 2) Solve the analytical expression for the boundary of the carbon emission fixed operation region, where the coefficients a n , b n and c n are respectively as follows:

[0105]

[0106] In the formula, and are the coordinates of the two endpoints of the linear constraint n, respectively.

[0107] Furthermore, the low-carbon scheduling model of the power-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool includes the power-hydrogen coupling system scheduling model and the green hydrogen chemical virtual energy pool scheduling model;

[0108] The objective function of the power-hydrogen coupling system scheduling model is as follows:

[0109]

[0110] In the formula, C3 is the total cost of optimal operation. C thermal is the thermal power generation cost, C HST is the operation and maintenance cost of the hydrogen storage tank, C EC is the hydrogen production cost, C FC is the operation cost of the hydrogen fuel cell, C dis is the new energy abandonment cost, C CO2 is the carbon emission cost, CE_buy The electricity purchase cost for the electricity - hydrogen coupling system is C H_buy The hydrogen purchase cost for the electricity - hydrogen coupling system.

[0111] Among them, C HST , C FC , C E_buy and C H_buy are respectively as follows:

[0112]

[0113] In the formula, c HST , c FC are respectively the unit operation and maintenance cost of the hydrogen storage tank and the unit power generation cost of the hydrogen fuel cell, c E_buy and c E_sale are respectively the unit electricity purchase cost and the unit electricity selling cost of the electricity - hydrogen coupling system to the green hydrogen chemical virtual energy pool, c H_buy and c H_sale are respectively the unit electricity purchase cost and the unit electricity selling cost of the electricity - hydrogen coupling system to the green hydrogen chemical virtual energy pool; and are respectively the hydrogen injection volume and the hydrogen release volume of the hydrogen storage tank at time t, is the power generation power of the hydrogen fuel cell at time t, and are respectively the electricity purchase volume and the electricity selling volume of the electricity - hydrogen coupling system to the q - th green hydrogen chemical virtual energy pool at time t, and are respectively the hydrogen purchase volume and the hydrogen selling volume of the electricity - hydrogen coupling system to the q - th green hydrogen chemical virtual energy pool at time t.

[0114] The objective function of the green hydrogen chemical virtual energy pool scheduling model is as follows:

[0115]

[0116] In the formula, C4 is the total daily revenue of the green hydrogen chemical virtual energy pool, C che_sale is the selling revenue of methanol, ammonia and methane of the green hydrogen chemical virtual energy pool, C ec is the production and compression cost of hydrogen, C hst is the operation and maintenance cost of the hydrogen storage tank, C trans is the transportation cost of hydrogen, C GT is the operation cost of the gas turbine, C CO2 is the carbon emission cost of the thermal power unit, C new is the new energy power generation cost, C dis_new is the new energy curtailment penalty cost, C P_buy is the electricity purchase cost of the green hydrogen chemical virtual energy pool from the upper - layer electricity - hydrogen coupling system, C H_buyis the hydrogen purchase cost of the green hydrogen chemical virtual energy pool from the upper-level power-to-hydrogen coupling system.

[0117] Furthermore, the constraint conditions of the power-to-hydrogen coupling system scheduling model include thermal power unit output constraint, thermal power unit ramp rate constraint, new energy unit output constraint, new energy unit ramp rate constraint, system carbon emission constraint, power flow constraint, hydrogen production link constraint, hydrogen energy storage and transportation constraint, and fuel cell operation constraint.

[0118] The constraint conditions of the green hydrogen chemical virtual energy pool scheduling model include gas turbine operation constraint, electrolytic water hydrogen production operation constraint, compression storage constraint, hydrogen storage tank operation constraint, hydrogen energy transportation constraint, chemical synthesis operation constraint, electric power balance constraint, carbon emission constraint, and power flow constraint.

[0119] The technical effect of the present invention is beyond doubt. The present invention can effectively improve the new energy consumption level of the power-to-hydrogen coupling system and enhance the economic efficiency of system operation. Description of the Drawings

[0120] Figure 1 is the comparison of the scheduling results of the case1-2 power-to-hydrogen coupling system;

[0121] Figure 2 is the operation mode of the power-to-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool;

[0122] Figure 3 is the low-carbon scheduling mode of the power-to-hydrogen coupling system considering the green hydrogen chemical virtual energy pool. Detailed Embodiments

[0123] The present invention will be further described below in conjunction with embodiments, but it should not be understood that the above-mentioned subject matter scope of the present invention is limited to the following embodiments. Without departing from the above-mentioned technical idea of the present invention, various substitutions and changes made according to ordinary technical knowledge and customary means in the art shall be included within the protection scope of the present invention.

[0124] Embodiment 1:

[0125] Refer to Figures 1 to 3 , a low-carbon scheduling method for a power-to-hydrogen coupling system considering the low-carbon regulation ability of a green hydrogen chemical virtual energy pool, comprising the following steps:

[0126] 1) Construct a carbon emission-fixed operation domain of the green hydrogen chemical virtual energy pool to quantify the low-carbon regulation ability of the green hydrogen chemical virtual energy pool;

[0127] 2) Construct an analytical expression for the boundary of the carbon emission-fixed operation domain of the green hydrogen chemical virtual energy pool;

[0128] 3) Based on the analytical expression of the carbon emission operation domain boundary of the green hydrogen chemical virtual energy pool, a low-carbon scheduling model for the electric-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool is constructed;

[0129] 4) Use the low-carbon scheduling model of the electric-hydrogen coupling system to realize the scheduling of the electric-hydrogen coupling system.

[0130] Example 2:

[0131] The low-carbon scheduling method for the electric-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool has the same technical content as Example 1. Further, the carbon emission operation domain of the green hydrogen chemical virtual energy pool is used to reflect the operation space of the green hydrogen chemical virtual energy pool under the low-carbon safe operation constraints, that is:

[0132]

[0133] In the formula, is the carbon emission operation domain of the q-th green hydrogen chemical virtual energy pool; Q is the total number of green hydrogen chemical virtual energy pools; is the x-th type of load power of the q-th green hydrogen chemical virtual energy pool that the power system needs to satisfy, N q is the total number of loads of the q-th green hydrogen chemical virtual energy pool; h(y q ) = 0 is the equality constraint that the green hydrogen chemical virtual energy pool needs to satisfy; s(y q ) ≤ 0 is the inequality constraint that the green hydrogen chemical virtual energy pool needs to satisfy.

[0134] Example 3:

[0135] The low-carbon scheduling method for the electric-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool has the same technical content as any one of Examples 1-2. Further, the equality constraints that the green hydrogen chemical virtual energy pool needs to satisfy include power balance constraints and electric-hydrogen-chemical coupling operation constraints;

[0136] The inequality constraints that the green hydrogen chemical virtual energy pool needs to satisfy include the safe operation constraints and carbon emission constraints of thermal power, new energy, and gas turbine units.

[0137] Example 4:

[0138] The low-carbon scheduling method for the electric-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool has the same technical content as any one of Examples 1-3. Further, the green hydrogen chemical virtual energy pool includes an electric energy subsystem model and a green hydrogen chemical subsystem model;

[0139] Among them, the constraint conditions of the electric energy subsystem model include the output constraint of thermal power units, the ramp constraint of thermal power units, the output constraint of wind and light, the ramp constraint of wind / solar, the operation constraint of gas turbines, the system carbon emission constraint, and the power flow constraint;

[0140] The green hydrogen chemical industry subsystem model includes the operation models of the hydrogen production, storage, transportation, and utilization links. The constraint conditions include the equipment operation constraints of electrolyzers, hydrogen storage tanks, tube trailers, and fuel cells, as well as the chemical production operation constraints.

[0141] Example 5:

[0142] A low-carbon scheduling method for an electricity-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool. The technical content is the same as any one of Examples 1-4. Further, the constraint conditions of the power subsystem model are as follows:

[0143] The output constraint of the thermal power unit is as follows:

[0144]

[0145] In the formula, P k,t is the output of the k-th thermal power unit at time t, and are the lower and upper limits of the output of the thermal power unit k, respectively.

[0146] The ramp constraint of the thermal power unit is as follows:

[0147]

[0148] In the formula, RU k and RD k represent the maximum upward and downward ramps of the thermal power unit, respectively. P k,t-1 is the output of the k-th thermal power unit at time t-1;

[0149] The output constraint of the new energy unit is as follows:

[0150]

[0151] In the formula, and are the lower and upper limits of the output P w,t of the wind turbine w, respectively; and are the lower and upper limits of the output P s,t of the photovoltaic unit s, respectively.

[0152] The ramp constraint of the new energy unit is as follows:

[0153]

[0154] In the formula, P w,t-1 is the output of the wind turbine w at time t-1; and are the upper and lower limits of the ramp rate of the wind turbine w, respectively; Ps,t-1 is the output of the photovoltaic unit s at time t-1; and are the upper and lower limits of the ramp rate of the photovoltaic unit s, respectively;

[0155] The operating constraints of the gas turbine are as follows:

[0156]

[0157] In the formula, P x,t is the output of the x-th gas turbine at time t, and are the lower and upper limits of the gas turbine output, respectively; and are the maximum upward ramp rate and the maximum downward ramp rate of the gas turbine, respectively. P x,t-1 is the output of the x-th gas turbine at time t-1;

[0158] The system carbon emission constraint is as follows:

[0159]

[0160] In the formula, N k is the total number of thermal power units; T is the scheduling period; e k is the carbon emission intensity of the thermal power unit; N x is the total number of thermal power units; e x is the carbon emission intensity of the gas turbine; Q carbon_emi is the carbon emission limit of the system.

[0161] The electric power balance constraint is as follows:

[0162]

[0163] In the formula, is the total output of the thermal power unit at time t, and are the total outputs of distributed wind and light at time t, is the total output of the gas turbine at time t, is the total output of the hydrogen fuel cell at time t, is the electric load at time t, is the power consumption of the electrolyzer at time t, is the electric power consumed by chemical synthesis at time t;

[0164] The power flow constraint is as follows:

[0165]

[0166] In the formula, N is the set of nodes of the system, Pi,t and Q i,t are the active power injection and reactive power injection of node i at time t, respectively; G ij and B ij are the real part and imaginary part of the element in the i-th row and j-th column of the nodal admittance matrix, respectively; U i,t is the voltage magnitude of node i at time t; θ ij,t is the phase angle difference of branch ij at time t; U i,min and U i,max are the lower and upper limits of the voltage magnitude of the node, respectively. U j,t is the voltage magnitude of node j at time t;

[0167] Example 6:

[0168] A low-carbon scheduling method for an electric-hydrogen coupling system considering the low-carbon regulation ability of a green hydrogen chemical virtual energy pool. The technical content is the same as any one of Examples 1-5. Further, in the green hydrogen chemical subsystem model, the operation model of the hydrogen production link is as follows:

[0169]

[0170] In the formula, is the electric power input to hydrogen production station g at time t, is the power consumed by the auxiliary equipment of hydrogen production station g at time t, α EC is the conversion coefficient of power consumption to hydrogen production flow, with the unit of MWh / Nm 3 , that is, the power consumption for producing each standard cubic meter of hydrogen, is the hydrogen production flow of hydrogen production station g at time t, P EC,min and P EC,max are the lower and upper limits of the electrolyzer input power, respectively.

[0171] The operation model of the hydrogen storage link is as follows:

[0172]

[0173] In the formula, C HST is the capacity of the hydrogen storage tank; is the energy stored in the hydrogen storage tank of hydrogen production station g at time t; m and respectively represent the hydrogen storage and hydrogen release flows in the hydrogen storage tank of hydrogen production station g at time t; η HST+ and η HST- respectively represent the hydrogen storage and hydrogen release efficiencies of the hydrogen storage tank; is the maximum capacity coefficient of the hydrogen storage tank; and respectively represent the upper limits of the hydrogen storage and hydrogen release flows of the hydrogen storage tank. is the energy stored in the hydrogen storage tank of hydrogen production station g at time t-1; is the initial moment, T D is the energy stored in the hydrogen storage tank of the hydrogen production station g; Δt is the time step;

[0174] The operation model of the hydrogen transportation link is as follows:

[0175]

[0176] u c,g,0 = u c,g,T g ∈ Ω HGS (19)

[0177]

[0178] Q c,min ≤ Q c,t ≤ Q c,max (22)

[0179]

[0180] In the formula, Ω HT is the set of tube trailers, Ω HGS = {HGS P2A , HGS P2MeOH , HGS P2G} is the set of hydrogen production stations, where, HGS P2A , HGS P2MeOH , HGS P2G respectively represent the hydrogen production stations of the ammonia synthesis system, methanol synthesis system and methane synthesis system; represents the hydrogen filling flow rate of tube trailer c at hydrogen production station g at time t. Q c,t represents the hydrogen storage capacity of tube trailer c at time t, Q c,t-1 represents the hydrogen storage capacity of tube trailer c at time t - 1, represents the hydrogen release flow rate of tube trailer c at hydrogen production station g at time t; Q c,min and Q c,max respectively represent the lower and upper limits of the hydrogen storage capacity of tube trailer c; is the state variable of hydrogen filling of tube trailer c at hydrogen production station g at time t, 1 represents hydrogen filling, otherwise 0; is the state variable of hydrogen release of tube trailer c at hydrogen production station g at time t, 1 represents hydrogen filling, otherwise 0. U c is the position state matrix of tube trailer c; u c,g,t is a 0-1 variable representing the position state of tube trailer c. When tube trailer c is at hydrogen production station g at time t, it is 1, otherwise 0; T D is the scheduling period; G is the total number of hydrogen production stations; is the hydrogen production flow rate of the hydrogen production station; is the upper limit of the hydrogen release flow rate and hydrogen filling flow rate of the tube trailer;

[0181] The operation models for the hydrogen utilization link include the P2A system operation model, the methanol synthesis system operation model, the methane synthesis system operation model, and the hydrogen fuel cell model;

[0182] The P2A system operation model is as follows:

[0183]

[0184] N2 + 3H2 ⇌ 2NH3, ΔH=-92.4kJ / mol (27)

[0185]

[0186] t = τ h +8(h - 1) (29)

[0187]

[0188] In the formula, is the power consumption of the compressor at time t, M N2 is the molar mass of nitrogen, R is the ideal gas constant, T is the temperature of the compressor, p3 and p1 are the pressures before and after nitrogen compression respectively, is the efficiency of the compressor; h represents the adjustment period of the ammonia synthesis reactor, and the value is 1, 2, 3, is the initial ammonia production flow rate of the ammonia synthesis reactor in the hth adjustment period, is the adjustment amount in the hth adjustment period, is τ h The ammonia production flow rate at time, represents the upper limit of the adjustment amount; is the ammonia synthesis rate at time t, and are the lower and upper limits of the ramp rate respectively; and are the lower and upper limits of the ammonia production rate respectively; Formula (27) is the chemical formula of the ammonia synthesis reaction; Formulas (28)-(30) are the operation models of the ammonia synthesis reactor adjustment period; Formula (31) is the load ramp rate constraint; Formula (32) is the ammonia synthesis rate constraint; Formulas (33)-(34) are the relationship equations between the ammonia production rate and the hydrogen injection flow rate and nitrogen injection flow rate in the ammonia synthesis process; is the ammonia synthesis rate at time t + 1; is the ammonia synthesis rate at time t + 1; ΔT AS is the scheduling period of the ammonia synthesis reactor, is the nitrogen flow rate at time t, λ P2A is the conversion rate of the ammonia synthesis process, is the hydrogen flow rate for chemical synthesis in the hydrogen production plant g at time t.

[0189] The operating model of the methanol synthesis system includes the operating models of the electrolytic water hydrogen production, carbon capture section, compression and buffering section, methanol synthesis and rectification sections of the methanol synthesis system;

[0190] The operating model of the carbon capture section is as follows:

[0191]

[0192] Wherein, is the energy consumption of the carbon capture device at time t, is the carbon dioxide emitted by the coal-fired power plant used for methanol synthesis at time t, η CCS,t is the carbon capture rate at time t, λ CCS is the energy consumption per unit of CO2 captured, is the carbon capture amount at time t.

[0193] The carbon emission Q of the thermal power unit at time t thermal,t is as follows:

[0194]

[0195] Wherein, N M is the number of thermal power units, γ n is the carbon emission factor of the nth thermal power unit; is the power generation of the thermal power unit n used for methanol synthesis at time t.

[0196] The operating model of the compression and buffering section is as follows:

[0197]

[0198] Wherein, is the electric power consumed by the P2MeOH system for compressing CO2 at time t, p4 and p1 are the pressures before and after CO2 compression respectively, is the efficiency of compressing CO2.

[0199] The operating model of the methanol synthesis and rectification sections

[0200] CO2 + 3H2 → CH3OH + H2O (39)

[0201]

[0202] Wherein, is the methanol production at time t, m MeOH,min and m MeOH,max are the lower and upper limits of the methanol yield respectively. λ P2MeOHIt is the conversion rate of the methanol synthesis process.

[0203] The operation model of the synthetic methane system includes the operation models of the electrolytic water hydrogen production, carbon capture, compression buffering, and methanation sections of the synthetic methane system;

[0204] The operation model of the carbon capture section of the synthetic methane system is as follows:

[0205]

[0206] In the formula, is the energy consumption of the carbon capture device of the P2G system at time t, is the carbon dioxide emitted by the coal-fired power plant used for synthetic methane at time t, and η CCS,t is the carbon capture rate at time t, and λ CCS is the energy consumption for capturing a unit of CO2, is the amount of carbon captured for synthetic methane at time t.

[0207] The carbon emission Q of the thermal power unit at time t thermal,t is as follows:

[0208]

[0209] In the formula, N G is the number of thermal power units used for carbon capture in the P2G system, and γ z is the carbon emission factor of the z-th thermal power unit; is the power generation of the z-th thermal power unit used for synthetic methane at time t.

[0210] The operation model of the compression buffering of the synthetic methane system is as follows:

[0211]

[0212] In the formula, is the electric power consumed for compressing CO2 in the P2G system at time t. is the molar mass of CO2;

[0213] The operation model of the methanation section is as follows:

[0214] CO2 + 4H2 → CH4 + 2H2O (47)

[0215]

[0216] In the formula, and are the lower and upper limits of the methane production rate respectively. λ P2G is the conversion efficiency of the methanation process.

[0217] The hydrogen fuel cell model is as follows:

[0218]

[0219] Where: is the output power of the fuel cell at time t; is the input power of the fuel cell at time t; η EC is the efficiency of the fuel cell. and are the minimum and maximum values of the fuel cell power, respectively.

[0220] Example 7:

[0221] A low-carbon scheduling method for an electricity-hydrogen coupling system considering the low-carbon regulation ability of a green hydrogen chemical virtual energy pool, the technical content is the same as any one of Examples 1-6. Further, the green hydrogen chemical virtual energy pool needs to satisfy the hydrogen energy balance constraint, that is:

[0222]

[0223] Where, is the hydrogen production flow rate at time t, and are the hydrogen storage amount and hydrogen release amount at time t, respectively, is the conventional hydrogen load at time t, is the amount of hydrogen used for transportation at time t, is the amount of hydrogen used for chemical synthesis at time t. is the amount of hydrogen consumed by the hydrogen fuel cell.

[0224] Example 8:

[0225] A low-carbon scheduling method for an electricity-hydrogen coupling system considering the low-carbon regulation ability of a green hydrogen chemical virtual energy pool, the technical content is the same as any one of Examples 1-7. Further, the steps for constructing the analytical expression of the boundary of the fixed carbon emission operation domain of the green hydrogen chemical virtual energy pool include:

[0226] 1) Piecewise linearly fit the two-dimensional fixed carbon emission operation domain space of the green hydrogen chemical virtual energy pool to obtain:

[0227]

[0228] Where, n is the number of equivalent linear constraints after piecewise linear fitting, P i and P j respectively represent the two-dimensional observation variables of the green hydrogen chemical virtual energy pool, a n , b n and c n are the coefficients of the linear constraint n, respectively.

[0229] 2) Solve the analytical expression for the boundary of the carbon emission reduction operation region, where the coefficients a n , b n and c n are respectively as follows:

[0230]

[0231] In the formula, and are respectively the two endpoint coordinates of the linear constraint n.

[0232] Embodiment 9:

[0233] A low-carbon scheduling method for an electricity-hydrogen coupling system considering the low-carbon regulation ability of a green hydrogen chemical virtual energy pool. The technical content is the same as any one of Embodiments 1-8. Further, it includes an electricity-hydrogen coupling system scheduling model and a green hydrogen chemical virtual energy pool scheduling model;

[0234] The objective function of the electricity-hydrogen coupling system scheduling model is as follows:

[0235] min C3 = C thermal + C HST + C EC + C FC + C dis + C CO2 + C E_buy + C H_buy (56)

[0236] In the formula, C3 is the total cost of optimized operation. C thermal is the thermal power generation cost, C HST is the operation and maintenance cost of the hydrogen storage tank, C EC is the hydrogen production cost, C FC is the operation cost of the hydrogen fuel cell, C dis is the cost of new energy abandonment, C CO2 is the carbon emission cost, C E_buy is the electricity purchase cost of the electricity-hydrogen coupling system, C H_buy is the hydrogen purchase cost of the electricity-hydrogen coupling system.

[0237] Among them, C HST , C FC , C E_buy and C H_buy are respectively as follows:

[0238]

[0239] In the formula, c HST , c FC are respectively the unit operation and maintenance cost of the hydrogen storage tank and the unit power generation cost of the hydrogen fuel cell, c E_buy and c E_saleare the unit power purchase cost and power selling cost of the power - hydrogen coupling system to the green hydrogen chemical virtual energy pool, respectively, c H_buy and c H_sale are the unit power purchase cost and power selling cost of the power - hydrogen coupling system to the green hydrogen chemical virtual energy pool, respectively; and are the hydrogen injection volume and hydrogen release volume of the hydrogen storage tank at time t, respectively, is the power generation power of the hydrogen fuel cell at time t, and are the power purchase volume and power selling volume of the power - hydrogen coupling system to the q - th green hydrogen chemical virtual energy pool at time t, respectively, and are the hydrogen purchase volume and hydrogen selling volume of the power - hydrogen coupling system to the q - th green hydrogen chemical virtual energy pool at time t, respectively.

[0240] The objective function of the green hydrogen chemical virtual energy pool scheduling model is as follows:

[0241]

[0242] In the formula, C4 is the total day - ahead revenue of the green hydrogen chemical virtual energy pool, C che_sale is the selling revenue of methanol, ammonia and methane of the green hydrogen chemical virtual energy pool, C ec is the production and compression cost of hydrogen, C hst is the operation and maintenance cost of the hydrogen storage tank, C trans is the transportation cost of hydrogen, C GT is the operation cost of the gas turbine, is the carbon emission cost of the thermal power unit, C new is the new - energy power generation cost, C dis_new is the new - energy curtailment penalty cost, C P_buy is the power purchase cost of the green hydrogen chemical virtual energy pool from the upper - layer power - hydrogen coupling system, C H_buy is the hydrogen purchase cost of the green hydrogen chemical virtual energy pool from the upper - layer power - hydrogen coupling system.

[0243] Example 10:

[0244] A low - carbon scheduling method for a power - hydrogen coupling system considering the low - carbon regulation ability of a green hydrogen chemical virtual energy pool, the technical content is the same as any one of Examples 1 - 9. Further, the constraint conditions of the power - hydrogen coupling system scheduling model include thermal power unit output constraint, thermal power unit ramp - rate constraint, new - energy unit output constraint, new - energy unit ramp - rate constraint, system carbon emission constraint, power flow constraint, hydrogen production link constraint, hydrogen energy storage and transportation constraint, and fuel cell operation constraint.

[0245] The constraint conditions of the green hydrogen chemical virtual energy pool scheduling model include gas turbine operation constraints, electrolytic water hydrogen production operation constraints, compression storage constraints, hydrogen storage tank operation constraints, hydrogen energy transportation constraints, chemical synthesis operation constraints, electric power balance constraints, carbon emission constraints, and power flow constraints.

[0246] Example 11:

[0247] A low-carbon scheduling method for an electric-hydrogen coupling system considering the low-carbon regulation ability of a green hydrogen chemical virtual energy pool, the steps include:

[0248] 1) Propose a quantification method for the low-carbon regulation ability of the green hydrogen chemical virtual energy pool based on the carbon emission operation domain;

[0249] 1.1) Construct the basic concept of the carbon emission operation domain of the green hydrogen chemical virtual energy pool;

[0250] The definition of the carbon emission operation domain of the green hydrogen chemical virtual energy pool is: considering the flexibility of hydrogen energy and chemical production in the green hydrogen chemical virtual energy pool, the set of operating points that satisfy the operation constraints, safety constraints, and carbon emission constraints of the power-green hydrogen-chemical coupling system. It can reflect the operating space of the green hydrogen chemical virtual energy pool and can be expressed as:

[0251]

[0252] In the formula, is the carbon emission operation domain of the qth green hydrogen chemical virtual energy pool; Q is the total number of green hydrogen chemical virtual energy pools; is the xth type of load power of the qth green hydrogen chemical virtual energy pool that the power system needs to satisfy, N q is the total number of loads of the qth green hydrogen chemical virtual energy pool; h(y q ) = 0 is the equality constraint that the green hydrogen chemical virtual energy pool needs to satisfy, including power balance constraints, electric-hydrogen-chemical coupling operation constraints, etc.; s(y q ) ≤ 0 is the inequality constraint that the green hydrogen chemical virtual energy pool needs to satisfy, including the safe operation constraints of thermal power, new energy, and gas turbine units, carbon emission constraints, etc.

[0253] 1.2) Construct the mathematical model of the carbon emission operation domain of the green hydrogen chemical virtual energy pool;

[0254] CCEOR-H2CVEP describes the maximum feasible space of the green hydrogen chemical virtual energy pool under low-carbon and safe operation constraints, which includes an electric energy subsystem model, a green hydrogen chemical subsystem model, etc. Its model specifically includes electric / hydrogen energy balance constraints, wind and solar distributed energy output constraints, electrolytic hydrogen production operation constraints, hydrogen energy storage and transportation constraints, chemical production constraints, gas turbine operation constraints, hydrogen fuel cell operation constraints, and carbon emission constraints. Its specific representation is as follows:

[0255] (1) Power electronics subsystem model

[0256] The operating constraints of the power electronics subsystem include the output constraints of thermal power units, the ramping constraints of thermal power units, the output constraints of wind and solar power, the ramping constraints of wind / solar power, the operating constraints of gas turbines, the system carbon emission constraints, and the power flow constraints.

[0257] ① Output constraints of thermal power units

[0258]

[0259] Wherein, P k,t is the output of the kth thermal power unit at time t, and are the lower and upper limits of the output of thermal power unit k, respectively.

[0260] ② Ramping constraints of thermal power units

[0261]

[0262] Wherein, RU k and RD k represent the maximum values of the upward and downward ramping of thermal power units, respectively.

[0263] ③ Output constraints of new energy units

[0264]

[0265] Wherein, and are the lower and upper limits of the output of wind turbine w, respectively; and are the lower and upper limits of the output of photovoltaic unit s, respectively.

[0266] ④ Ramping constraints of new energy units

[0267]

[0268] Wherein, P w,t-1 is the output of wind turbine w at time t-1; and are the upper and lower limits of the ramping rate of wind turbine w, respectively; P s,t-1 is the output of photovoltaic unit s at time t-1; and are the upper and lower limits of the ramping rate of photovoltaic unit s, respectively;

[0269] ⑤ Operating constraints of gas turbines

[0270]

[0271] Wherein, Px,t is the output of the x-th gas turbine at time t, and are the lower and upper limits of the gas turbine output respectively; and are the maximum upward ramp rate and the maximum downward ramp rate of the gas turbine respectively.

[0272] ⑥ System carbon emission constraint

[0273]

[0274] In the formula, N k is the total number of thermal power units; T is the scheduling period; e k is the carbon emission intensity of the thermal power unit; N x is the total number of thermal power units; e x is the carbon emission intensity of the gas turbine; Q carbon_emi is the carbon emission limit of the system.

[0275] ⑦ Electric power balance constraint

[0276]

[0277] In the formula, is the total output of the thermal power unit at time t, and are the total outputs of distributed wind and light at time t, is the total output of the gas turbine at time t, is the total output of the hydrogen fuel cell at time t, is the electrical load at time t, is the power consumption of the electrolyzer at time t, is the electrical power consumed by chemical synthesis at time t;

[0278] ⑧ Power flow constraint

[0279]

[0280] In the formula, N is the set of nodes in the system, P i,t and Q i,t are the active injection power and the reactive injection power of node i at time t respectively; G ij and B ij are the real part and the imaginary part of the i-th row and j-th column in the nodal admittance matrix respectively; U i,t is the voltage amplitude of node i at time t; θ ij,t is the phase angle difference of branch ij at time t; U i,min and U i,max are the lower and upper limits of the voltage amplitude of the node respectively.

[0281] (2) Green Hydrogen Chemical Subsystem Model

[0282] The green hydrogen chemical subsystem model includes the operation models of hydrogen production, storage, transportation, and utilization. The hydrogen produced by the electrolyzer is supplied to the fuel cell and for chemical use. The green hydrogen chemical subsystem model includes the equipment operation constraints of the electrolyzer, hydrogen storage tank, tube trailer, fuel cell, and the operation constraints of chemical production.

[0283] ① Hydrogen Production Link Model

[0284] The object of this paper is a large-scale industrial hydrogen production station. The power consumed in the hydrogen production section is mainly supplied to the supporting auxiliary equipment and electrolysis. In the hydrogen production project, multiple single electrolyzers are generally connected in parallel to meet the large-scale hydrogen demand. Through the cooperation of multiple electrolyzers, the load of the electrolyzer can vary continuously in the range of 5% - 100%, and the energy conversion efficiency is approximately linear. Therefore, the model of the electrolyzer constructed in this paper is as follows:

[0285]

[0286] In the formula, is the electrical power input to the hydrogen production station g at time t, is the power consumed by the auxiliary equipment of the hydrogen production station g at time t, and α EC is the conversion coefficient of power consumption to hydrogen production flow rate, with the unit of MWh / Nm 3 , that is, the power consumption for producing each standard cubic meter of hydrogen, is the hydrogen production flow rate of the hydrogen production station g at time t, and P EC,min and P EC,max are the lower and upper limits of the input power of the electrolyzer, respectively.

[0287] ② Hydrogen Energy Storage and Transportation Model

[0288] The model of the hydrogen storage tank is as follows:

[0289]

[0290] In the formula, C HST is the capacity of the hydrogen storage tank; is the energy stored in the hydrogen storage tank of the hydrogen production station g at time t; m and respectively represent the hydrogen storage and hydrogen release flow rates of the hydrogen storage tank in the hydrogen production station g at time t; η HST+ and η HST- respectively represent the hydrogen storage and hydrogen release efficiencies of the hydrogen storage tank; is the maximum capacity coefficient of the hydrogen storage tank; and respectively represent the upper limits of the hydrogen storage and hydrogen release flow rates of the hydrogen storage tank.

[0291] Each chemical production plant is relatively close in location. Therefore, long-tube trailers suitable for short-distance transportation are used as the main hydrogen transportation method. Assume that the hydrogen production section and the chemical synthesis section in each chemical production park are in the same location, and only consider the transportation of hydrogen between hydrogen production stations. In this paper, the position status matrix is used to describe the transportation status of long-tube trailers, as shown in the following formula:

[0292]

[0293] In the formula, U c is the position status matrix of long-tube trailer c; u c,g,t is a 0-1 variable representing the position status of long-tube trailer c. When long-tube trailer c is at hydrogen production station g at time t, it is 1, otherwise it is 0; in this paper, only hydrogen production stations in three chemical industrial parks are considered, so the value of g is 1, 2, 3; T D is the scheduling period; G is the total number of hydrogen production stations.

[0294] Considering the limitations of long-tube trailers in terms of transportation time and transportation capacity, the hydrogen transportation model constructed in this paper is as follows:

[0295]

[0296] u c,g,0 = u c,g,T g∈Ω HGS

[0297] In the formula, Ω HT is the set of long-tube trailers, Ω HGS ={HGS P2A ,HGS P2MeOH ,HGS P2G} is the set of hydrogen production stations, where HGS P2A ,HGS P2MeOH ,HGS P2G represent the hydrogen production stations of the synthetic ammonia system, the synthetic methanol system, and the synthetic methane system respectively; Equation (2.9) means that at a certain moment, long-tube trailer c can only be located at one hydrogen production station; Equation (2.10) means that the initial and final position statuses of long-tube trailer c are the same within the scheduling period for scheduling in the next period.

[0298] The relationship between the hydrogen production flow rate of the hydrogen production station and the hydrogen injection flow rate of the long-tube trailer is as follows:

[0299]

[0300] In the formula, represents the hydrogen filling flow rate of long-tube trailer c at hydrogen production station g at time t.

[0301] The amount of hydrogen stored in the long-tube trailer is as follows:

[0302]

[0303] Q c,min ≤Q c,t ≤Q c,max

[0304]

[0305] wherein, Q c,t represents the hydrogen storage capacity of the tube trailer c at time t, represents the hydrogen release flow rate of the tube trailer c at the hydrogen production station g at time t; Q c,min and Q c,max respectively represent the lower limit and the upper limit of the hydrogen storage capacity of the tube trailer c; is the state variable of hydrogen filling of the tube trailer c at the hydrogen production station g at time t, 1 represents hydrogen filling, otherwise it is 0; is the state variable of hydrogen release of the tube trailer c at the hydrogen production station g at time t, 1 represents hydrogen filling, otherwise it is 0. Equations (21)-(22) are the constraints on the hydrogen carrying capacity of the tube trailer; Equations (23)-(24) are the constraints on the hydrogen filling and release amounts of the tube trailer; Equation (25) restricts that the tube trailer cannot fill and release hydrogen simultaneously.

[0306] ③ Chemical synthesis model

[0307] a) (Power to ammonia, P2A) system operation model

[0308] The P2A process mainly includes air separation, compression buffering and ammonia synthesis links.

[0309] Air separation, compression buffering

[0310] The nitrogen required for ammonia synthesis is obtained from the air separation section and needs to be pressurized step by step by a multi-stage compressor. The electric energy consumed is:

[0311]

[0312] wherein, is the power consumption of the compressor at time t, is the molar mass of nitrogen, R is the ideal gas constant, T is the temperature of the compressor, p3 and p1 are the pressures of nitrogen before and after compression respectively, is the efficiency of the compressor.

[0313] Ammonia synthesis

[0314] Currently, the ammonia synthesis technology is mainly based on the Haber-Bosch process, in which hydrogen and nitrogen react exothermically to synthesize ammonia. The chemical formula of the reaction is as follows:

[0315] N2 + 3H2 ⇌ 2NH3, ΔH=-92.4 kJ / mol

[0316] Since the load regulation process in the ammonia synthesis process is relatively slow, and this change process is approximately a unit step response process with a time constant of about 2 h, and the time to reach stability for the unit step response is about 4 times the time constant, the scheduling period of the ammonia synthesis reactor is taken as ΔT AS = 8 h, that is, there are 3 adjustment cycles for the ammonia synthesis reactor on the day-ahead time scale, and it will not be adjusted again until its state reaches stability again. Its model is as follows:

[0317]

[0318] τ h The correlation relationship with t is:

[0319] t = τ h + 8(h - 1)

[0320]

[0321] In the formula, h represents the adjustment cycle of the ammonia synthesis reactor, and the value is 1, 2, 3, is the initial ammonia production flow rate of the ammonia synthesis reactor in the hth adjustment cycle, is the adjustment amount in the hth adjustment cycle, is τ h The ammonia production flow rate at the moment, represents the upper limit of the adjustment amount.

[0322] Due to the large inertia and time delay in process units such as synthesis towers, circulation pipelines, and ammonia separation in the ammonia synthesis section, it is necessary to limit the ramp rate of the load:

[0323]

[0324] In the formula, is the ammonia synthesis rate at time t, and are the lower and upper limits of the ramp rate respectively.

[0325] The ammonia synthesis yield needs to be maintained within a given range:

[0326]

[0327] In the formula, and are the lower and upper limits of the ammonia yield respectively.

[0328] Considering the material conservation relationship and conversion rate in the ammonia synthesis process, the relationship between the ammonia synthesis yield and the hydrogen injection flow rate and nitrogen injection flow rate in the ammonia synthesis process is:

[0329]

[0330] b) Power-to-methanol (P2MeOH) system operation model

[0331] The P2MeOH process mainly includes hydrogen production by electrolyzing water, carbon capture section, compression and buffering section, methanol synthesis and rectification section. Since the model of hydrogen production by electrolyzing water has been described in Section 2.2, it will not be elaborated here too much.

[0332] Carbon capture section

[0333] In this paper, the CO2 captured by carbon capture technology (CCS) is used as the raw material gas for synthesizing methanol. The CCS technology is to separate CO2 from the flue gas generated by coal-fired power plants and obtain high-purity CO2 after treatment. Its operation model is as follows:

[0334]

[0335] In the formula, is the energy consumption of the carbon capture device at time t, is the carbon dioxide emitted from the coal-fired power plant used for synthesizing methanol at time t, η CCS,t is the carbon capture rate at time t, λ CCS is the energy consumption for capturing a unit of CO2, is the carbon capture amount at time t.

[0336] Among them, Q thermal,t is the carbon emission of the thermal power unit at time t, and its calculation formula is as follows:

[0337]

[0338] In the formula, N M is the number of thermal power units, γ n is the carbon emission factor of the nth thermal power unit, with the unit of kgCO2 / kWh. is the power generation power of the thermal power unit n used for synthesizing methanol at time t.

[0339] Compression and buffering

[0340] The carbon dioxide obtained from the carbon capture section needs to pass through an intermediate condenser and be multi-stage compressed and finally enter the mixer. The electric energy consumed in the compression link is:

[0341]

[0342] In the formula, is the electric power consumed by the P2MeOH system for compressing CO2 at time t, p4 and p1 are the pressures before and after CO2 compression respectively, For the efficiency of compressing CO2.

[0343] Methanol synthesis and rectification

[0344] The carbon dioxide captured by carbon capture is condensed and compressed, and then enters the methanol synthesis reactor through a mixer together with the green hydrogen obtained from the electrolysis of alkaline water to react. The chemical reaction formula in the methanol synthesis process is as follows:

[0345] CO2 + 3H2 → CH3OH + H2O

[0346] The yield in the methanol synthesis process needs to be maintained within a given range:

[0347]

[0348] In the formula, is the methanol production at time t, m MeOH,min and m MeOH,max are the lower and upper limits of the methanol yield, respectively.

[0349] Since the adjustment time of the methanol synthesis process is fast, when the composition of the gas mixture at the inlet of the synthesis reactor changes, the synthesis process can reach a new steady state within dozens of seconds, and the ramp rate is 5%-13% / min or even higher. Therefore, the ramp constraint and adjustment time constraint of the methanol synthesis process are not considered in this paper.

[0350] Considering the material conservation relationship and conversion rate in the methanol synthesis process, the relationship between the methanol yield and the hydrogen injection flow rate and nitrogen injection flow rate in the methanol synthesis process is:

[0351]

[0352] In the formula, λ P2MeOH is the conversion rate in the methanol synthesis process.

[0353] c) Operation model of the power-to-gas (P2G) system

[0354] The P2G process includes electrolysis of water to produce hydrogen, carbon capture, compression buffering, and methanation sections. The models of the electrolysis of water to produce hydrogen, carbon capture, and compression buffering sections are similar to those of P2MeOH and will not be elaborated here.

[0355] Carbon capture section

[0356] The operation model of the carbon capture section is as follows:

[0357]

[0358] In the formula, is the energy consumption of the carbon capture device of the P2G system at time t, The CO2 emitted by a coal-fired power plant for synthesizing methane at time t, η CCS,t is the carbon capture rate at time t, and λCCS is the energy consumption for capturing a unit of CO2. is the amount of carbon captured for synthesizing methane at time t.

[0359] Among them, Q thermal,t is the carbon emission of the thermal power unit at time t, and its calculation formula is as follows:

[0360]

[0361] In the formula, N G is the number of thermal power units for carbon capture in the P2G system, and γ z is the carbon emission factor of the z-th thermal power unit, with the unit of kgCO2 / kWh. is the power generation of the z-th thermal power unit for synthesizing methane at time t.

[0362] Compression buffer

[0363] The CO2 obtained in the carbon capture section needs to pass through an intermediate condenser and be multi-stage compressed and finally enter the mixer. The electric energy consumed in the compression link is:

[0364]

[0365] In the formula, is the electric power consumed by the P2G system for compressing CO2 at time t. is the molar mass of CO2;

[0366] Methanation section

[0367] The reaction formula of the methanation process is as follows:

[0368] CO2 + 4H2 → CH4 + 2H2O

[0369] Since the adjustment time of the methane synthesis process is fast, usually at the minute level, and the ramp rate is 4% / min, the ramp constraint and adjustment time constraint of the methane synthesis process are not considered in this paper.

[0370] The yield in the methane synthesis process needs to be maintained within a given range:

[0371]

[0372] In the formula, and are the lower and upper limits of the methane yield, respectively.

[0373] Considering the material conservation relationship and conversion rate in the methane synthesis process, the relationship between the methane yield and the hydrogen injection flow rate and nitrogen injection flow rate in the methane synthesis process is:

[0374]

[0375] where λ P2G is the conversion efficiency of the methanation process.

[0376] ④ Hydrogen fuel cell model

[0377] The model of the fuel cell is:

[0378]

[0379] where: is the output power of the fuel cell at time t; is the input power of the fuel cell at time t; η EC is the efficiency of the fuel cell.

[0380] The operating constraints of the fuel cell are:

[0381]

[0382] where: and are the minimum and maximum values of the fuel cell power, respectively.

[0383] ⑤ Hydrogen energy balance constraint

[0384]

[0385] where, is the hydrogen production flow rate at time t, and are the hydrogen storage amount and hydrogen release amount at time t, respectively, is the conventional hydrogen load at time t, is the amount of hydrogen used for transportation at time t, is the amount of hydrogen used for chemical synthesis at time t.

[0386] 2) Propose an analytical expression method for the boundary of the carbon emission fixed operation region of the green hydrogen chemical virtual energy pool;

[0387] 2.1) Piecewise linear fitting of the two-dimensional carbon emission fixed operation region space of the green hydrogen chemical virtual energy pool;

[0388] After piecewise linear fitting, the two-dimensional carbon emission fixed operation region space of the green hydrogen chemical virtual energy pool can be expressed as follows:

[0389]

[0390] where n is the number of equivalent linear constraints after piecewise linear fitting, P i and P jRespectively represent the two-dimensional observation variables of the green hydrogen chemical virtual energy pool, a n , b n and c n Are the coefficients of the linear constraint n respectively.

[0391] 2.2) Solve the analytical expression of the boundary of the carbon emission fixed operation region.

[0392] The coefficient solution formula is as follows:

[0393]

[0394] In the formula, and Are the coordinates of the two endpoints of the linear constraint n respectively.

[0395] 3) Propose a low-carbon scheduling model for the electricity-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool;

[0396] 3.1) Construct a scheduling model for the electricity-hydrogen coupling system;

[0397] Therefore, with the maximum benefit of the electricity-hydrogen coupling system as the goal, and taking the adjustable space of power supply and hydrogen supply of the green hydrogen chemical virtual energy pool as the upper-layer constraint condition, a low-carbon scheduling model of the electricity-hydrogen coupling system based on the carbon emission fixed operation region is constructed to determine the scheduling strategy of the system, and the electricity and hydrogen interaction quantities of the optimized electricity-hydrogen coupling system are transmitted to the decision-making center of the green hydrogen chemical virtual energy pool. Among them, the mathematical model of the optimized scheduling of the electricity-hydrogen coupling system is as follows:

[0398]

[0399] In the formula, C3 is the total cost of optimized operation. C thermal Is the thermal power generation cost, C HST Is the operation and maintenance cost of the hydrogen storage tank, C EC Is the hydrogen production cost, C FC Is the operation cost of the hydrogen fuel cell, C dis Is the cost of new energy abandonment, C CO2 Is the carbon emission cost, C E_buy Is the electricity purchase cost of the electricity-hydrogen coupling system, C H_buy Is the hydrogen purchase cost of the electricity-hydrogen coupling system. Among them, C HST , C FC , C E_buy and C H_buy The specific calculation formulas are as follows:

[0400]

[0401] In the formula, c HST , c FCare the unit operation and maintenance costs of the hydrogen storage tank and the unit power generation cost of the hydrogen fuel cell, respectively, c E_buy and c E_sale are the unit power purchase cost and the unit power selling cost of the power-hydrogen coupling system to the green hydrogen chemical virtual energy pool, respectively, c H_buy and c H_sale are the unit power purchase cost and the unit power selling cost of the power-hydrogen coupling system to the green hydrogen chemical virtual energy pool; and are the hydrogen injection volume and the hydrogen release volume of the hydrogen storage tank at time t, respectively, is the power generation power of the hydrogen fuel cell at time t, and are the power purchase volume and the power selling volume of the power-hydrogen coupling system to the qth green hydrogen chemical virtual energy pool at time t, respectively, and are the hydrogen purchase volume and the hydrogen selling volume of the power-hydrogen coupling system to the qth green hydrogen chemical virtual energy pool at time t, respectively.

[0402] The constraint conditions include the output constraint of thermal power units, the ramping constraint of thermal power units, the output constraint of new energy units, the ramping constraint of new energy units, the system carbon emission constraint, the power flow constraint, the hydrogen production link constraint, the hydrogen energy storage and transportation constraint, and the fuel cell operation constraint.

[0403] 3.2) Construct the scheduling model of the green hydrogen chemical virtual energy pool;

[0404] The lower-layer green hydrogen chemical virtual energy pool takes the maximum day-ahead revenue as the objective function, and at the same time takes the operating point of the upper-layer optimized green hydrogen chemical virtual energy pool as a condition to construct the scheduling model of the green hydrogen chemical virtual energy pool, so as to obtain the scheduling strategy of the lower-layer green hydrogen chemical virtual energy pool. The specific expression of the objective function is as follows:

[0405]

[0406] In the formula, C4 is the total day-ahead revenue of the green hydrogen chemical virtual energy pool, C che_sale is the selling revenue of methanol, ammonia and methane of the green hydrogen chemical virtual energy pool, C ec is the production and compression cost of hydrogen, C hst is the operation and maintenance cost of the hydrogen storage tank, C trans is the transportation cost of hydrogen, C GT is the operation cost of the gas turbine, C CO2 is the carbon emission cost of the thermal power unit, C new is the new energy power generation cost, C dis_new is the new energy curtailment penalty cost, C P_buy is the power purchase cost of the green hydrogen chemical virtual energy pool from the upper-layer power-hydrogen coupling system, C H_buyIt is the hydrogen purchase cost of the green hydrogen chemical virtual energy pool for the upper-level power-to-hydrogen coupling system.

[0407] The constraint conditions include gas turbine operation constraints, electrolytic water hydrogen production operation constraints, compression storage constraints, hydrogen storage tank operation constraints, hydrogen energy transportation constraints, chemical synthesis operation constraints, electric power balance constraints, carbon emission constraints, and power flow constraints.

[0408] 4) Through comparative case studies, it is verified that the proposed method can effectively improve the new energy consumption level of the power-to-hydrogen coupling system and enhance the economic efficiency of system operation.

[0409] Example 12:

[0410] To verify the effectiveness of the low-carbon scheduling method for the power-to-hydrogen coupling system considering the green hydrogen chemical virtual energy pool described in any one of Examples 1-11, this example conducts a comparative analysis through the following two case studies.

[0411] Case 1: The green hydrogen chemical virtual energy pool and the power-to-hydrogen coupling system operate separately. That is, the green hydrogen chemical virtual energy pool determines its operating conditions and transmits power to the upper-level power-to-hydrogen coupling system, and the upper-level power-to-hydrogen coupling system determines its operating strategy based on this condition.

[0412] Case 2: The method in this paper, a low-carbon scheduling method for the power-to-hydrogen coupling system considering the low-carbon regulation ability of the green hydrogen chemical virtual energy pool, that is, using the carbon emission fixed operation domain to equivalently replace the operating boundary of the green hydrogen chemical virtual energy pool.

[0413] The economic cost comparison between Case 1 and Case 2 is shown in Table 1. Among them, the hydrogen energy operation cost includes the electrolyzer operation cost, hydrogen storage tank operation and maintenance cost, and fuel cell operation cost. The operation cost of the green hydrogen chemical virtual energy pool includes the electrolyzer operation cost, buffer section operation and maintenance cost, and long tube trailer transportation cost.

[0414] Table 1 Economic cost comparison between Case 1 and Case 2

[0415]

[0416]

[0417] The economic cost comparison between Case 1 and Case 2 is shown in Table 1. Among them, the hydrogen energy operation cost includes the electrolyzer operation cost, hydrogen storage tank operation and maintenance cost, and fuel cell operation cost. The operation cost of the green hydrogen chemical virtual energy pool includes the electrolyzer operation cost, buffer section operation and maintenance cost, and long tube trailer transportation cost.

[0418] As can be seen from Table 1, the total cost of the power-to-hydrogen coupling system in Case 1 is 1.583×10 9yuan. The total cost of the power-to-hydrogen coupling system in Case 2 is 1.344×10 9 yuan, which is 15% lower than that in Case 1; the power purchase cost of the power-to-hydrogen coupling system in Case 1 is 2.79×10 7 yuan, and the power purchase cost of the power-to-hydrogen coupling system in Case 2 is 7.37×10 7 yuan, indicating that the power purchase volume of the power-to-hydrogen coupling system in Case 2 for the downstream green hydrogen chemical virtual energy has increased significantly; the hydrogen sales revenue in Case 1 is 6.35×10 6 yuan, and the power purchase cost in Case 2 is 2.76×10 6 yuan, indicating that the power-to-hydrogen coupling system in Case 2 purchases hydrogen from the downstream green hydrogen chemical virtual energy pool. It can be seen that in the optimal operation of the power-to-hydrogen coupling system, considering the operation boundary of the downstream green hydrogen chemical virtual energy pool can effectively reduce the carbon emission cost and the abandoned energy cost of the power-to-hydrogen coupling system, and improve the low-carbon operation level of the system.

[0419] In the optimal dispatching of the downstream green hydrogen chemical virtual energy, the total revenue of H2CVEP1 in Case 1 is 2.309×10 6 yuan, and the total revenue of H2CVEP1 in Case 2 is 0.506×10 6 yuan, which is 78.08% lower than that in Case 1; the total revenue of H2CVEP2 in Case 1 is 3.22×10 6 yuan, and the total revenue of H2CVEP1 in Case 2 is 1.58×10 6 yuan, which is 50.9% lower than that in Case 1. The chemical product sales revenues of H2CVEP1-2 in Case 1 are 3.765×10 6 yuan and 3.838×10 6 yuan respectively, and the chemical product sales revenues of H2CVEP1-2 in Case 2 are 1.077×10 6 yuan and 1.458×10 6 yuan respectively, which are 71% and 62% lower than those in Case 1 respectively. It can be seen that considering the feasible space of the green hydrogen chemical virtual energy pool leads to a decrease in the chemical product sales revenue and a reduction in the overall profit margin of the system.

[0420] Generally speaking, the total operating cost of Case 1 is 1.577×10 8 yuan, and the total operating cost of Case 2 is 1.342×10 8 yuan, which is 14.9% lower than that in Case 1; the total carbon emission cost of Case 1 is 2.4×10 8 yuan, and the total carbon emission cost of Case 2 is 1.22×10 8Yuan, a 49.1% reduction compared to Case 1. It can be seen that considering the feasible space of the green hydrogen chemical virtual energy pool can effectively reduce the operating cost of the entire system and promote the low-carbon operation of the system.

[0421] The specific reason analysis is as follows. The scheduling results of the power-to-hydrogen coupling system in Case 1-2 are as Figure 1 shown. From Figure 1 (a)-(d), it can be seen that during the periods of 0:00-8:00 and 16:00-24:00, the thermal power output in Case 2 is much smaller than that in Case 1. At the same time, the electricity purchased by Case 2 from the lower-layer green hydrogen chemical virtual energy pool is relatively large. This is because in Case 1, in order to maximize its own benefits, the green hydrogen chemical virtual energy pool purchases a large amount of electricity and hydrogen from the upper-layer power-to-hydrogen coupling system. For the upper-layer power-to-hydrogen coupling system, the supply pressure of electricity and hydrogen loads increases. To ensure the power supply and hydrogen supply balance of the system, the utilization rate of thermal power is increased, which not only increases the power generation cost, but also significantly increases the carbon emissions. Therefore, considering the operating domain of the green hydrogen chemical virtual energy pool can avoid the dependence of the lower-layer green hydrogen chemical virtual energy pool on the upper-layer power-to-hydrogen coupling system, and instead provide a certain low-carbon support capacity for the upper layer.

Claims

1. A low-carbon dispatching method for an electricity-hydrogen coupling system considering the low-carbon regulation capability of a virtual energy pool for green hydrogen chemical industry, characterized in that: The following steps are involved: 1) Construct a green hydrogen chemical virtual energy pool to determine the carbon emission operation domain, and quantify the low-carbon regulation capability of the green hydrogen chemical virtual energy pool. 2) Construct an analytical expression for the boundary of the carbon emission operation domain of the virtual energy pool of green hydrogen chemical industry; 3) Based on the analytical expression of the carbon emission operation domain boundary of the green hydrogen chemical virtual energy pool, a low-carbon scheduling model of the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool is constructed; 4) Use the low-carbon scheduling model of the electricity-hydrogen coupling system to realize the scheduling of the electricity-hydrogen coupling system.

2. The low-carbon dispatching method for the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool according to claim 1 is characterized in that: The carbon emission operation domain of the green hydrogen chemical virtual energy pool is used to reflect the operation space of the green hydrogen chemical virtual energy pool under the constraints of low-carbon and safe operation, namely: In the formula, is the fixed carbon emission operation domain of the qth green hydrogen chemical virtual energy pool; Q is the total number of green hydrogen chemical virtual energy pools; is the x-th load power of the q-th green hydrogen chemical virtual energy pool that the power system needs to meet, N q is the total load of the qth green hydrogen chemical virtual energy pool; h(y q )=0 is the equality constraint that the virtual energy pool of green hydrogen chemical industry needs to satisfy; s(y q )≤0 is the inequality constraint that the green hydrogen chemical virtual energy pool must satisfy.

3. The low-carbon dispatching method for the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool according to claim 2 is characterized in that: The equation constraints that the green hydrogen chemical virtual energy pool needs to satisfy include power balance constraints and electricity-hydrogen-chemical coupled operation constraints; The inequality constraints that the green hydrogen chemical virtual energy pool needs to meet include safe operation constraints of thermal power, new energy, and gas turbine units, and carbon emission constraints.

4. The low-carbon dispatching method for the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool according to claim 2 is characterized in that: The green hydrogen chemical virtual energy pool includes the electric energy subsystem model and the green hydrogen chemical subsystem model; Among them, the constraints of the power subsystem model include thermal power unit output constraints, thermal power unit ramp constraints, wind and solar output constraints, wind / solar ramp constraints, gas turbine operation constraints, system carbon emission constraints, and power flow constraints; The green hydrogen chemical subsystem model includes the operation models of hydrogen production, storage, transportation and use. The constraints include the equipment operation constraints of electrolyzers, hydrogen storage tanks, long-tube trailers, fuel cells, and chemical production operation constraints.

5. The low-carbon dispatching method for the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool according to claim 4 is characterized in that: The constraints of the power subsystem model are as follows: The output constraints of thermal power units are as follows: Where P k,t is the output of the kth thermal power unit at time t, and are the lower and upper limits of the output of thermal power unit k respectively. The climbing constraints of thermal power units are as follows: In the formula, RU k and RD k Respectively represent the maximum value of the upward and downward climbing of the thermal power unit. k,t-1 is the output of the kth thermal power unit at time t-1; The output constraints of new energy units are as follows: P s min ≤P s,t ≤P s max (5) In the formula, and are the output P of wind turbine w respectively w,t The lower and upper limits of and are the output P of photovoltaic unit s respectively s,t lower and upper limits. The climbing constraints of new energy units are as follows: Where P w,t-1 is the output of wind turbine w at time t-1; and are the upper and lower limits of the climbing rate of wind turbine w respectively; P s,t-1 is the output of photovoltaic unit s at time t-1; and are the upper and lower limits of the ramp rate of the photovoltaic unit s respectively; The gas turbine operating constraints are as follows: Where P x,t is the output of the x-th gas turbine at time t, and are the lower and upper limits of gas turbine output respectively; and are the maximum upward ramp rate and maximum downward ramp rate of the gas turbine respectively. x,t-1 is the output of the xth gas turbine at time t-1; The system carbon emission constraints are as follows: Where N k is the total number of thermal power units; T is the dispatching period; e k is the carbon emission intensity of thermal power units; N x is the total number of thermal power units; e x is the carbon emission intensity of the gas turbine; Q carbon_emi is the carbon emission limit of the system. The electrical power balance constraints are as follows: In the formula, is the total output of the thermal power unit at time t, and is the total output of distributed wind and solar power at time t, is the total output of the gas turbine at time t, is the total output of the hydrogen fuel cell at time t, is the electrical load at time t, is the power consumption of the electrolytic cell at time t, is the electrical power consumed by chemical synthesis at time t; The power flow constraints are as follows: Where N is the set of nodes in the system, P i,t and Q i,t are the active injection power and reactive injection power of node i at time t respectively; G ij and B ij are the real and imaginary parts of the i-th row and j-th column in the node admittance matrix; U i,t is the voltage amplitude of node i at time t; U j,t is the voltage amplitude of node j at time t; θ ij,t is the phase difference of branch ij at time t; U i,min and U i,max are the lower and upper limits of the node voltage amplitude respectively.

6. The low-carbon dispatching method for the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool according to claim 4 is characterized in that: In the green hydrogen chemical subsystem model, the operation model of the hydrogen production link is as follows: In the formula, is the electric power input to the hydrogen production station g at time t, is the power consumed by the auxiliary equipment of the hydrogen production station g at time t, α EC is the conversion coefficient between power consumption and hydrogen production flow rate, is the hydrogen production flow rate of hydrogen production station g at time t, P EC,min and P EC,max are the lower and upper limits of the electrolytic cell input power respectively. The operation model of the hydrogen storage link is as follows: In the formula, C HST is the capacity of the hydrogen storage tank; The energy stored in the hydrogen storage tank of hydrogen production station g at time t; and They represent the hydrogen storage and release flow rates of the hydrogen storage tank g in the hydrogen production station at time t respectively; is the maximum capacity factor of the hydrogen storage tank; and They respectively represent the upper limits of the hydrogen storage and release flow rates of the hydrogen storage tank. E is the energy stored in the hydrogen storage tank of hydrogen production station g at time t-1; HST,0 , is the initial time, T D The energy stored in the hydrogen storage tank of the hydrogen production station g; Δt is the time step; The operation model of the hydrogen transmission link is as follows: in c,g,0 =in c,g,T g∈Ω HGS (19) Q c,min ≤Q c,t ≤Q c,max (22) In the formula, Ω HT For long tube trailer assembly, Ω HGS ={HGS P2A ,HGS P2MeOH ,HGS P2G } is a collection of hydrogen production stations, among which HGS P2A ,HGS P2MeOH ,HGS P2G They represent hydrogen production stations for synthetic ammonia system, synthetic methanol system and synthetic methane system respectively; Q represents the hydrogen filling flow of the long tube trailer c at the hydrogen production station g at time t. c,t represents the hydrogen storage capacity of the long tube trailer c at time t, Q c,t-1 represents the hydrogen storage capacity of the long tube trailer c at time t-1, represents the hydrogen discharge flow rate of the long-tube trailer c at the hydrogen production station g at time t; Q c,min and Q c,max They represent the lower limit and upper limit of the hydrogen storage capacity of the long tube trailer c respectively; is the state variable of the long tube trailer c filling hydrogen at the hydrogen production station g at time t, 1 means filling hydrogen, otherwise it is 0; is the state variable of the long tube trailer c releasing hydrogen at the hydrogen production station g at time t, 1 means hydrogen is charged, otherwise it is 0. c is the position state matrix of the long tube trailer c; u c,g,t is a 0-1 variable representing the position state of the long tube trailer c. When the long tube trailer c is located at the hydrogen production station g at time t, it is 1, otherwise it is 0; T D is the scheduling period; G is the total number of hydrogen production stations; is the hydrogen production flow rate of the hydrogen production station; It is the upper limit of hydrogen discharge flow rate and hydrogen filling flow rate of long tube trailer; The operation models of the hydrogen use link include the P2A system operation model, the synthetic methanol system operation model, the synthetic methane system operation model, and the hydrogen fuel cell model; The P2A system operation model is as follows: N2+3H22NH3,ΔH=-92.4kJ / mol (27) t=τ h +8(h-1) (29) In the formula, is the power consumption of the compressor at time t, is the molar mass of nitrogen, R is the ideal gas constant, T is the compressor temperature, p3 and p1 are the pressures of nitrogen before and after compression, respectively. is the efficiency of the compressor; h represents the adjustment period of the synthetic ammonia reactor, and its value is 1, 2, 3. is the initial ammonia production flow rate of the synthetic ammonia reactor in the hth adjustment cycle, is the adjustment amount of the hth adjustment cycle, is τ h The ammonia production flow rate at the time, Indicates the upper limit of the adjustment amount; is the rate of ammonia synthesis at time t, and are the lower and upper limits of the climbing rate respectively; and are the lower and upper limits of ammonia yield respectively; formula (27) is the chemical formula of ammonia synthesis reaction; formulas (28)-(30) are the adjustment cycle operation model of ammonia synthesis reactor; formula (31) is the load ramp rate constraint; formula (32) is the ammonia synthesis yield constraint; formulas (33)-(34) are the relationship equations between ammonia yield and the injection flow rate of hydrogen and nitrogen in the ammonia synthesis process; is the rate of ammonia synthesis at time t+1; ΔT AS is the scheduling cycle of the synthetic ammonia reactor, is the nitrogen flow rate at time t, λ P2A is the conversion rate of the synthetic ammonia process, is the hydrogen flow rate used for chemical product synthesis in hydrogen production station g at time t. The operation model of the synthetic methanol system includes the operation models of the electrolysis of water to produce hydrogen, the carbon capture section, the compression buffer section, the methanol synthesis and distillation section of the synthetic methanol system; The operation model of the carbon capture section is as follows: In the formula, is the energy consumption of the carbon capture device at time t, is the carbon dioxide emitted by the coal-fired power plant used to synthesize methanol at time t, η CCS,t is the carbon capture rate at time t, λ CCS is the energy consumption per unit CO2 captured, is the carbon capture amount at time t. Carbon emissions of thermal power units at time t Q thermal,t As shown below: Where N M is the number of thermal power units, γ n is the carbon emission factor of the nth thermal power unit, in kgCO2 / kWh. is the power generation capacity of thermal power unit n used to synthesize methanol at time t. The operation model of the compression buffer section is as follows: In the formula, is the electrical power consumed by the P2MeOH system to compress CO2 at time t, p4 and p1 are the pressures before and after CO2 compression, respectively. The efficiency of compressing CO2. Operation model of methanol synthesis and distillation section CO2+3H2→CH3OH+H2O(39) In the formula, is the methanol production at time t, m MeOH,min and m MeOH,max are the lower and upper limits of methanol yield respectively. P2MeOH is the conversion rate of the methanol synthesis process. The operation model of the synthetic methane system includes the operation models of the electrolysis of water to produce hydrogen, carbon capture, compression buffer and methane chemical industry sections of the synthetic methane system; The operation model of the carbon capture section of the synthetic methane system is as follows: In the formula, is the energy consumption of the carbon capture device of the P2G system at time t, is the carbon dioxide emitted by coal-fired power plants used to synthesize methane at time t, η CCS,t is the carbon capture rate at time t, λ CCS is the energy consumption per unit CO2 captured, is the amount of carbon captured for methane synthesis at time t. Carbon emissions of thermal power units at time t Q thermal,t As shown below: Where N G is the number of thermal power units used for carbon capture in the P2G system, γ z is the carbon emission factor of the zth thermal power unit, in kgCO2 / kWh. is the power generation capacity of thermal power unit z used to synthesize methane at time t. The operation model of the synthetic methane system compression buffer is as follows: In the formula, is the electrical power consumed by the P2G system to compress CO2 at time t. The operation model of the methanogenization section is as follows: CO2+4H2→CH4+2H2O(47) In the formula, and The methane yield The lower and upper limits of λ P2G is the conversion efficiency of the methanogenesis process. The hydrogen fuel cell model is shown below: Where: is the output power of the fuel cell at time t; is the input power of the fuel cell at time t; η EC The efficiency of the fuel cell. and are the minimum and maximum values ​​of the fuel cell power, respectively.

7. The low-carbon dispatching method for the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool according to claim 4 is characterized in that: The virtual energy pool of green hydrogen chemical industry needs to meet the hydrogen energy balance constraints, namely: In the formula, is the hydrogen production flow rate at time t, and are the amount of hydrogen stored and released at time t, is the normal hydrogen load at time t, is the amount of hydrogen used for transportation at time t, is the amount of hydrogen used for chemical synthesis at time t; The amount of hydrogen consumed by a hydrogen fuel cell.

8. The low-carbon dispatching method for the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool according to claim 1 is characterized in that: The steps of constructing the analytical expression of the carbon emission operation domain boundary of the green hydrogen chemical virtual energy pool include: 1) Piecewise linear fitting of the two-dimensional fixed carbon emission operation domain space of the virtual energy pool of green hydrogen chemical industry yields: Where n is the number of equivalent linear constraints after piecewise linear fitting, P i and P j They represent the two-dimensional observation variables of the virtual energy pool of green hydrogen chemical industry, a n 、b n and c n are the coefficients of the linear constraint n respectively. 2) Solve the analytical expression for the boundary of the fixed carbon emission operation domain, where the coefficient a n 、b n and c n They are as follows: In the formula, and are the coordinates of the two endpoints of the linear constraint n.

9. The low-carbon dispatching method for the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool according to claim 1 is characterized in that: The low-carbon dispatch model of the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool includes the electricity-hydrogen coupling system dispatch model and the green hydrogen chemical virtual energy pool dispatch model; The objective function of the electricity-hydrogen coupling system scheduling model is as follows: Where C3 is the total cost of the optimized operation. thermal is the cost of thermal power generation, C HST is the operation and maintenance cost of the hydrogen storage tank, C EC is the cost of hydrogen production, C FC is the operating cost of hydrogen fuel cells, C dis is the cost of abandoned energy from new energy sources, C CO2 is the carbon emission cost, C E_buy is the electricity purchase cost of the electricity-hydrogen coupling system, C H_buy The cost of purchasing hydrogen for the electricity-hydrogen coupling system. Among them, C HST , C FC , C E_buy and C H_buy They are as follows: In the formula, c HST 、c FC are the unit operation and maintenance cost of hydrogen storage tanks and the unit power generation cost of hydrogen fuel cells, respectively. E_buy and c E_sale are the unit electricity purchase cost and electricity sales cost of the electricity-hydrogen coupling system to the green hydrogen chemical virtual energy pool, c H_buy and c H_sale They are the unit electricity purchase cost and electricity sales cost of the electricity-hydrogen coupling system to the green hydrogen chemical virtual energy pool; and are the hydrogen injection and release amounts of the hydrogen storage tank at time t, is the power generated by the hydrogen fuel cell at time t, and are the electricity purchase and sales of the electricity-hydrogen coupling system to the qth green hydrogen chemical virtual energy pool at time t, and They are respectively the amount of hydrogen purchased and sold by the electricity-hydrogen coupling system to the qth green hydrogen chemical virtual energy pool at time t. The objective function of the green hydrogen chemical virtual energy pool scheduling model is as follows: maxC4 Where C4 is the total revenue of the virtual energy pool of green hydrogen chemical industry, C che_sale is the sales revenue of methanol, ammonia and methane in the virtual energy pool of green hydrogen chemical industry, C ec is the cost of hydrogen production and compression, C hst is the operation and maintenance cost of the hydrogen storage tank, C trans is the transportation cost of hydrogen, C GT is the gas turbine operating cost, is the carbon emission cost of thermal power units, C new is the cost of renewable energy power generation, C dis_new The penalty cost for abandoning new energy, C P_buy The cost of electricity purchased from the virtual energy pool of green hydrogen chemical industry to the upper-level electricity-hydrogen coupling system, C H_buy The cost of purchasing hydrogen from the virtual energy pool of green hydrogen chemical industry to the upper-level electricity-hydrogen coupling system.

10. The low-carbon dispatching method for the electricity-hydrogen coupling system considering the low-carbon regulation capability of the green hydrogen chemical virtual energy pool according to claim 9 is characterized in that: The constraints of the electricity-hydrogen coupling system scheduling model include thermal power unit output constraints, thermal power unit ramping constraints, new energy unit output constraints, new energy unit ramping constraints, system carbon emission constraints, flow constraints, hydrogen production constraints, hydrogen energy storage and transportation constraints, and fuel cell operation constraints. The constraints of the green hydrogen chemical virtual energy pool scheduling model include gas turbine operation constraints, water electrolysis hydrogen production operation constraints, compression storage constraints, hydrogen storage tank operation constraints, hydrogen energy transportation constraints, chemical synthesis operation constraints, electric power balance constraints, carbon emission constraints and flow constraints.

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