Virtual power plant low-carbon flexible operation method considering chemical production

Abstract

The invention relates to a virtual power plant low-carbon flexible operation method considering chemical production. The method comprises the following steps: 1) constructing an objective function of a virtual power plant low-carbon flexible operation model considering chemical production; 2) constructing balance constraints of energy substances of electricity, hydrogen, heat, carbon dioxide, nitrogen, methane, methanol and urea of the virtual power plant low-carbon flexible operation model considering chemical production; 3) constructing constraints of pressure swing adsorption nitrogen generation equipment, methane preparation equipment, methanol preparation equipment, ammonia gas preparation equipment and urea preparation equipment, and constraints of a carbon capture unit, carbon sequestration equipment, an electrolytic bath, a hydrogen fuel cell, a cogeneration unit and a gas-fired boiler of the virtual power plant low-carbon flexible operation model considering chemical production; and 4) solving the virtual power plant low-carbon flexible operation model considering chemical production to obtain an operation decision of the virtual power plant.

Description

Technical Field

[0001] The present application relates to the technical field of virtual power plant operation, and particularly to a method for low-carbon flexible operation of a virtual power plant. Background Art

[0002] From the perspective of the current global carbon emission structure, the carbon emissions in the production processes of electric power and heat energy are at a high level. Moreover, in the short term, it is difficult to fundamentally change the coal-based power generation mode in China. Therefore, reducing carbon emissions in the production processes of electric power and heat energy has become a key link in achieving low-carbon transformation. The emergence of virtual power plants provides a new direction for solving this problem. At the same time, the emergence and application of low-carbon technologies such as carbon capture and power-to-gas inject new vitality into the green and low-carbon transformation of virtual power plants.

[0003] Introduce carbon capture and power-to-gas equipment in the virtual power plant modeling. By coupling the two, the carbon capture equipment can capture the carbon dioxide emitted in the production processes of electric power and heat energy, and transport it as a raw material to the power-to-gas equipment for the methanation and methanolization treatment of hydrogen. This method not only reduces the overall carbon emissions of the system operation, realizes the recycling of carbon dioxide, but also effectively improves the economic efficiency of the virtual power plant operation. In the chemical industry, the related reactions of producing methane and methanol from carbon dioxide and hydrogen, producing ammonia from nitrogen and hydrogen, and producing urea from carbon dioxide and ammonia are all important ways to effectively utilize carbon, nitrogen, and hydrogen elements. If these chemical reactions can be integrated into the operation system of the virtual power plant to achieve cross-field coordination between energy and chemicals, it can not only further expand the utilization ways of carbon, nitrogen, and hydrogen resources by the virtual power plant, improve the resource utilization efficiency, but also create more economic and environmental benefits. Summary of the Invention

[0004] Based on this, in view of the above problems, the present invention provides a method for low-carbon flexible operation of a virtual power plant considering chemical production, and the method includes the following steps:

[0005] Step (1), construct the objective function of the low-carbon flexible operation model of the virtual power plant considering chemical production;

[0006] Step (2), construct the energy and material balance constraints of electricity, hydrogen, heat, carbon dioxide, nitrogen, methane, methanol, and urea for the low-carbon flexible operation model of the virtual power plant considering chemical production;

[0007] Step (3), construct the constraints of pressure swing adsorption nitrogen production equipment, methane production equipment, methanol production equipment, ammonia production equipment, urea production equipment, carbon capture unit, carbon sequestration equipment, electrolyzer, hydrogen fuel cell, combined heat and power unit, and gas boiler for the low-carbon flexible operation model of the virtual power plant considering chemical production;

[0008] Step (4): According to the objective function in step (1), and combining the constraints in steps (2) and (3), solve the low-carbon flexible operation model of the virtual power plant considering chemical production to obtain the operation decision of the virtual power plant.

[0009] Further, in step (1), the objective function for constructing the low-carbon flexible operation model of the virtual power plant considering chemical production is expressed as follows:

[0010]

[0011] In the formula, s is the renewable energy output scenario, hereinafter referred to as scenario s, t is the operation period, and t - 1 is the previous operation period of operation period t; T is the total number of operation periods, and S is the total number of renewable energy output scenarios. represents the occurrence probability of scenario s. represents the hydrogen selling price in the t-th period. represents the hydrogen sales volume of the virtual power plant in the t-th period under scenario s. represents the methane selling price in the t-th period. represents the mass of methane sold by the virtual power plant in the t-th period under scenario s. represents the methanol selling price in the t-th period. represents the mass of methanol sold by the virtual power plant in the t-th period under scenario s. represents the urea selling price in the t-th period. represents the mass of urea sold by the virtual power plant in the t-th period under scenario s. represents the carbon dioxide sequestration price in the t-th period. represents the carbon dioxide sequestration volume of the virtual power plant in the t-th period under scenario s, ω GB is the unit operation and maintenance cost of the gas boiler of the virtual power plant, ω GT is the unit operation and maintenance cost of the combined heat and power unit of the virtual power plant, ω WP is the unit operation and maintenance cost of the wind turbine of the virtual power plant, ω PV is the unit operation and maintenance cost of the photovoltaic unit of the virtual power plant, ω ET is the unit operation and maintenance cost of the electrolyzer of the virtual power plant, ω FC is the unit operation and maintenance cost of the hydrogen fuel cell of the virtual power plant. is the unit operation and maintenance cost of the pressure swing adsorption nitrogen production device of the virtual power plant. is the unit operation and maintenance cost of the methane production equipment of the virtual power plant. is the unit operation and maintenance cost of the methanol production equipment of the virtual power plant. is the unit operation and maintenance cost of the urea production equipment of the virtual power plant. represents the heat production power of the gas boiler of the virtual power plant in the t-th period under scenario s. Represents the power generation power of the combined heat and power unit of the virtual power plant in the t-th time period under scenario s. Respectively represent the power generation power of the wind power and photovoltaic power generation units of the virtual power plant in the t-th time period under scenario s. Represents the electric power consumed by the electrolyzer of the virtual power plant in the t-th time period under scenario s. Represents the power generation power of the hydrogen fuel cell of the virtual power plant in the t-th time period under scenario s. Represents the electric power consumed by the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th time period under scenario s. Represents the electric power consumed by the methane production equipment of the virtual power plant in the t-th time period under scenario s. Represents the electric power consumed by the methanol production equipment of the virtual power plant in the t-th time period under scenario s. Represents the electric power consumed by the urea production equipment of the virtual power plant in the t-th time period under scenario s. Respectively represent the amount of natural gas purchased by the gas boiler and combined heat and power supply machine of the virtual power plant in the t-th time period under scenario s, μ GAS Represents the purchase price of unit natural gas, ω AWP Is the unit penalty cost for abandoned wind of the virtual power plant, ω APV Is the unit penalty cost for abandoned light of the virtual power plant. Represents the abandoned wind power of the virtual power plant in the t-th time period under scenario s. Represents the abandoned light power of the virtual power plant in the t-th time period under scenario s. Represents the electricity purchase price from the power grid at time t. Represents the electricity selling price to the power grid at time t. Represents the electricity purchase power of the virtual power plant in the t-th time period under scenario s, μ C Represents the unit carbon price in the t-th time period under scenario s. Represents the excess carbon emissions of the virtual power plant in the t-th time period under scenario s.

[0012] Furthermore, the specific process of step (2) is as follows:

[0013] (201) Establish the power, hydrogen, and heat energy balance constraints of the virtual power plant:

[0014]

[0015] In the formula, Represents the electric power consumed by the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th time period under scenario s. Represents the electric power consumed by the methane production equipment of the virtual power plant in the t-th time period under scenario s. Denotes the electric power consumed by the methanol production equipment of the virtual power plant in the t-th period under scenario s. Denotes the electric power consumed by the urea production equipment of the virtual power plant in the t-th period under scenario s. Denotes the electric power consumed by the carbon capture unit of the virtual power plant for carbon dioxide capture in the t-th period under scenario s. Denotes the electric power consumed by the virtual power plant for carbon dioxide sequestration in the t-th period under scenario s. Denotes the basic electric load power of the virtual power plant in the t-th period under scenario s. Denotes the electric power consumed by the electrolyzer of the virtual power plant in the t-th period under scenario s. Respectively denote the wind / solar power curtailment of the virtual power plant in the t-th period under scenario s. Respectively denote the power generation of the wind and photovoltaic power generation units of the virtual power plant in the t-th period under scenario s. Denotes the purchased electric power of the virtual power plant in the t-th period under scenario s. Denotes the power generation of the combined heat and power unit of the virtual power plant in the t-th period under scenario s. Denotes the power generation of the hydrogen fuel cell of the virtual power plant in the t-th period under scenario s. Denotes the amount of hydrogen produced by the electrolyzer of the virtual power plant in the t-th period under scenario s. Denotes the amount of hydrogen consumed by the virtual power plant for methane synthesis in the t-th period under scenario s. Denotes the amount of hydrogen consumed by the virtual power plant for methanol synthesis in the t-th period under scenario s. [[ID=3​0]]Denotes the amount of hydrogen consumed by the virtual power plant for ammonia synthesis in the t-th period under scenario s. Denotes the amount of hydrogen consumed by the hydrogen fuel cell of the virtual power plant in the t-th period under scenario s. Denotes the hydrogen sales volume of the virtual power plant in the t-th period under scenario s. Denotes the hydrogen storage volume of the virtual power plant in the t-th period under scenario s. Denotes the hydrogen storage volume of the virtual power plant in the (t - 1)-th period under scenario s. Denotes the basic heat load power of the virtual power plant in the t-th period under scenario s. Denotes the heat production power of the gas boiler of the virtual power plant in the t-th period under scenario s. Denotes the heat production power of the combined heat and power unit of the virtual power plant in the t-th period under scenario s. [[ID=​46]]Denotes the heat production power of the combined heat and power unit of the virtual power plant in the t-th period under scenario s. Denotes the heat production power of the ammonia production equipment of the virtual power plant in the t-th period under scenario s;

[0016] (202) Establish the material balance constraints of carbon dioxide, nitrogen, methane, methanol, and urea in a virtual power plant

[0017]

[0018] Wherein, represents the mass of carbon dioxide generated by the combined heat and power unit of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide generated by the gas-fired boiler of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide captured by the carbon capture unit of the virtual power plant in the t-th period under scenario s, represents the initial carbon quota of the virtual power plant under scenario s, represents the excess carbon emissions of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide consumed for synthesizing methane by the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide consumed for synthesizing methanol by the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide consumed for synthesizing urea by the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide sequestration of the virtual power plant in the t-th period under scenario s, represents the carbon dioxide storage volume of the carbon storage equipment of the virtual power plant in the t-th period under scenario s, represents the carbon dioxide storage volume of the carbon storage equipment of the virtual power plant in the (t - 1)-th period under scenario s, represents the mass of nitrogen produced by the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th period under scenario s, represents the mass of nitrogen consumed for synthesizing ammonia by the ammonia manufacturing equipment of the virtual power plant in the t-th period under scenario s, represents the mass of methane generated by the methane production equipment of the virtual power plant in the t-th period under scenario s, represents the mass of methane consumed by the combined heat and power unit of the virtual power plant in the t-th period under scenario s, represents the mass of methane consumed by the gas-fired boiler of the virtual power plant in the t-th period under scenario s, represents the mass of methane sold by the virtual power plant in the t-th period under scenario s, represents the mass of methanol produced by the methanol production equipment of the virtual power plant in the t-th period under scenario s, represents the mass of methanol sold by the virtual power plant in the t-th period under scenario s, represents the mass of urea produced by the urea production equipment of the virtual power plant in the t-th period under scenario s, represents the mass of urea sold by the virtual power plant in the t-th period under scenario s.

[0019] Furthermore, the specific process of step (3) is as follows:

[0020] (301) Establish the constraints of the pressure swing adsorption nitrogen production, methane production, methanol production, ammonia production, and urea production equipment

[0021]

[0022]

[0023] wherein, represents the mass of nitrogen produced by the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th period under the scenario s, represents the power-to-gas efficiency of the pressure swing adsorption nitrogen production equipment of the virtual power plant, represents the air mass flow rate entering the pressure swing adsorption system in the t-th period under the scenario s, T PSA represents the thermodynamic temperature of the pressure swing adsorption system, Rg AIR represents the gas constant of air, P OUT and P IN represent the outlet pressure and inlet pressure of the pressure swing adsorption system respectively, η m represents the mechanical efficiency of the pressure swing adsorption nitrogen production equipment, represents the isentropic efficiency of the pressure swing adsorption process of the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th period under the scenario s, Δt represents the time interval, represents the maximum nitrogen production of the pressure swing adsorption nitrogen production equipment of the virtual power plant, represents the ratio of the relative molecular mass of methane to carbon dioxide, represents the ratio of the relative molecular mass of methane to hydrogen, represents the power-to-gas efficiency of the methane production equipment of the virtual power plant, represents the maximum methane production of the methane production equipment of the virtual power plant, represents the ratio of the relative molecular mass of methanol to carbon dioxide, represents the ratio of the relative molecular mass of methanol to hydrogen, represents the power-to-gas efficiency of the methanol production equipment of the virtual power plant, represents the maximum methanol production of the methanol production equipment of the virtual power plant, represents the ratio of the relative molecular mass of ammonia to carbon dioxide, represents the ratio of the relative molecular mass of ammonia to hydrogen, represents the power-to-gas efficiency of the ammonia production equipment of the virtual power plant, represents the maximum ammonia production of the ammonia production equipment of the virtual power plant, represents the ratio of the relative molecular mass of urea to carbon dioxide, represents the ratio of the relative molecular masses of urea and hydrogen, represents the urea production efficiency of the urea production equipment of the virtual power plant, represents the maximum urea production of the urea production equipment of the power plant;

[0024] (302) Establish constraints for the carbon capture unit, carbon sequestration equipment, electrolyzer, hydrogen fuel cell, cogeneration unit, and gas boiler

[0025]

[0026] In the formula, represents the power consumption rate of the carbon capture unit of the virtual power plant, represents the carbon capture rate of the carbon capture unit of the virtual power plant at the t-th time period under scenario s, represents the maximum carbon sequestration capacity of the carbon sequestration equipment of the virtual power plant, α ET represents the electricity-to-hydrogen efficiency of the electrolyzer of the virtual power plant, represents the maximum hydrogen production of the electrolyzer of the virtual power plant, α FC represents the power generation efficiency of the hydrogen fuel cell of the virtual power plant, η FCH represents the heat conversion efficiency of the hydrogen fuel cell, P FC,MAX represents the maximum power generation of the hydrogen fuel cell of the virtual power plant, η GTE represents the power generation efficiency of the cogeneration unit of the virtual power plant, Lmt represents the lower heating value of natural gas, P GT,MAX represents the maximum power generation of the cogeneration unit of the virtual power plant, η GB represents the thermal efficiency of the gas boiler of the virtual power plant, H GB,MAX represents the maximum heating power of the gas boiler of the virtual power plant, α GT is the carbon emission coefficient of the cogeneration unit, α GB is the carbon emission coefficient of the gas boiler.

[0027] Furthermore, in step (4), a low-carbon flexible operation model of the virtual power plant considering chemical production is written in GAMS software, and the compiled model is solved to obtain a low-carbon flexible operation plan for the virtual power plant.

[0028] Beneficial effects. Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0029] A low-carbon flexible operation method for a virtual power plant considering chemical production proposed by the present invention takes into account carbon dioxide capture, hydrogen production, carbon dioxide utilization in the virtual power plant, as well as the production of methane, methanol, and urea from nitrogen and hydrogen. By scheduling the virtual power plant considering chemical production, the carbon emissions of the virtual power plant are reduced, and the consumption capacity of the virtual power plant for new energy is improved. Moreover, by supplying the waste heat from chemical production to the heat load to meet part of the heat load demand, the flexibility of the virtual power plant operation is improved. The present invention takes into account the chemical production in the virtual power plant, increases the utilization ways of carbon dioxide and hydrogen energy in the virtual power plant, promotes the consumption of new energy in the virtual power plant, and reduces the carbon emissions of the virtual power plant. Moreover, by supplying the waste heat from chemical production to the heat load to meet part of the heat load demand, the flexibility of the virtual power plant operation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic flow chart of the operation method for a virtual power plant considering chemical production;

[0031] Figure 2 It is a graph of the operation results of the virtual power plant. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] In one embodiment, as Figure 1 shown, the present invention provides a low-carbon flexible operation method for a virtual power plant considering chemical production, and the method includes the following steps:

[0034] Step (1), constructing the objective function of the low-carbon flexible operation model of the virtual power plant considering chemical production;

[0035] Step (2), constructing the power, hydrogen, heat, carbon dioxide, nitrogen, methane, methanol, and urea energy substance balance constraints of the low-carbon flexible operation model of the virtual power plant considering chemical production;

[0036] Step (3), constructing the constraints of the pressure swing adsorption nitrogen production equipment, methane production equipment, methanol production equipment, ammonia production equipment, urea production equipment, carbon capture unit, carbon storage equipment, electrolyzer, hydrogen fuel cell, cogeneration unit, and gas boiler in the low-carbon flexible operation model of the virtual power plant considering chemical production;

[0037] Step (4), according to the objective function in step (1), and combining the constraints in steps (2) and (3), solving the low-carbon flexible operation model of the virtual power plant considering chemical production to obtain the operation decision of the virtual power plant.

[0038] Further, in step (1), the objective function for constructing a low-carbon flexible operation model of a virtual power plant considering chemical production is expressed as follows:

[0039]

[0040] In the formula, s is the renewable energy output scenario, hereinafter referred to as scenario s, t is the operation period, and t - 1 is the previous operation period of operation period t; T is the total number of operation periods, and S is the total number of renewable energy output scenarios, represents the occurrence probability of scenario s, represents the hydrogen selling price in the t-th period, represents the hydrogen sales volume of the virtual power plant in the t-th period under scenario s, represents the methane selling price in the t-th period, represents the mass of methane sold by the virtual power plant in the t-th period under scenario s, represents the methanol selling price in the t-th period, represents the mass of methanol sold by the virtual power plant in the t-th period under scenario s, represents the urea selling price in the t-th period, represents the mass of urea sold by the virtual power plant in the t-th period under scenario s, represents the carbon dioxide sequestration price in the t-th period, represents the carbon dioxide sequestration volume of the virtual power plant in the t-th period under scenario s, ω GB is the unit operation and maintenance cost of the gas boiler of the virtual power plant, ω GT is the unit operation and maintenance cost of the combined heat and power unit of the virtual power plant, ω WP is the unit operation and maintenance cost of the wind turbine of the virtual power plant, ω PV is the unit operation and maintenance cost of the photovoltaic unit of the virtual power plant, ω ET is the unit operation and maintenance cost of the electrolyzer of the virtual power plant, ω FC is the unit operation and maintenance cost of the hydrogen fuel cell of the virtual power plant, is the unit operation and maintenance cost of the pressure swing adsorption nitrogen production device of the virtual power plant, is the unit operation and maintenance cost of the methane production equipment of the virtual power plant, is the unit operation and maintenance cost of the methanol production equipment of the virtual power plant, is the unit operation and maintenance cost of the urea production equipment of the virtual power plant, represents the heat production power of the gas boiler of the virtual power plant in the t-th period under scenario s, represents the power generation power of the combined heat and power unit of the virtual power plant in the t-th period under scenario s, respectively represent the power generation of the wind power and photovoltaic power generation units of the virtual power plant at the t-th time period under scenario s, represents the electric power consumed by the electrolyzer of the virtual power plant at the t-th time period under scenario s, represents the power generation of the hydrogen fuel cell of the virtual power plant at the t-th time period under scenario s, represents the electric power consumed by the pressure swing adsorption nitrogen production equipment of the virtual power plant at the t-th time period under scenario s, represents the electric power consumed by the methane production equipment of the virtual power plant at the t-th time period under scenario s, represents the electric power consumed by the methanol production equipment of the virtual power plant at the t-th time period under scenario s, represents the electric power consumed by the urea production equipment of the virtual power plant at the t-th time period under scenario s, respectively represent the amount of natural gas purchased by the gas boiler and combined heat and power unit of the virtual power plant at the t-th time period under scenario s, μ GAS represents the purchase price per unit of natural gas, ω AWP is the unit penalty cost for wind curtailment of the virtual power plant, ω APV is the unit penalty cost for light curtailment of the virtual power plant, represents the wind curtailment power of the virtual power plant at the t-th time period under scenario s, represents the light curtailment power of the virtual power plant at the t-th time period under scenario s, represents the electricity purchase price from the power grid at time t, represents the electricity selling price to the power grid at time t, represents the electricity purchase power of the virtual power plant at the t-th time period under scenario s, μ C represents the unit carbon price at the t-th time period under scenario s, represents the excess carbon emissions of the virtual power plant at the t-th time period under scenario s.

[0041] Furthermore, the specific process of step (2) is as follows:

[0042] (201) Establish the power, hydrogen, and heat energy balance constraints of the virtual power plant:

[0043]

[0044] In the formula, represents the electric power consumed by the pressure swing adsorption nitrogen production equipment of the virtual power plant at the t-th time period under scenario s, represents the electric power consumed by the methane production equipment of the virtual power plant at the t-th time period under scenario s, represents the electric power consumed by the methanol production equipment of the virtual power plant at the t-th time period under scenario s, Denotes the electric power consumed by the urea production equipment of the virtual power plant in the t-th period under scenario s. Denotes the electric power consumed by the carbon capture unit of the virtual power plant for carbon dioxide capture in the t-th period under scenario s. Denotes the electric power consumed by the virtual power plant for carbon dioxide sequestration in the t-th period under scenario s. Denotes the basic electric load power of the virtual power plant in the t-th period under scenario s. Denotes the electric power consumed by the electrolyzer of the virtual power plant in the t-th period under scenario s. Respectively denote the wind curtailment / power curtailment power of the virtual power plant in the t-th period under scenario s. Respectively denote the power generation powers of the wind power and photovoltaic power generation units of the virtual power plant in the t-th period under scenario s. Denotes the power purchase power of the virtual power plant in the t-th period under scenario s. Denotes the power generation power of the combined heat and power unit of the virtual power plant in the t-th period under scenario s. Denotes the power generation power of the hydrogen fuel cell of the virtual power plant in the t-th period under scenario s. Denotes the amount of hydrogen produced by the electrolyzer of the virtual power plant in the t-th period under scenario s. Denotes the amount of hydrogen consumed by the virtual power plant for methane synthesis in the t-th period under scenario s. Denotes the amount of hydrogen consumed by the virtual power plant for methanol synthesis in the t-th period under scenario s. Denotes the amount of hydrogen consumed by the virtual power plant for ammonia synthesis in the t-th period under scenario s. Denotes the amount of hydrogen consumed by the hydrogen fuel cell of the virtual power plant in the t-th period under scenario s. Denotes the hydrogen sales volume of the virtual power plant in the t-th period under scenario s. Denotes the hydrogen storage volume of the virtual power plant in the t-th period under scenario s. Denotes the hydrogen storage volume of the virtual power plant in the (t - 1)-th period under scenario s. Denotes the basic heat load power of the virtual power plant in the t-th period under scenario s. Denotes the heat production power of the gas boiler of the virtual power plant in the t-th period under scenario s. Denotes the heat production power of the combined heat and power unit of the virtual power plant in the t-th period under scenario s. Denotes the heat production power of the combined heat and power unit of the virtual power plant in the t-th period under scenario s. Denotes the heat production power of the ammonia production equipment of the virtual power plant in the t-th period under scenario s;

[0045] (202) Establish the material balance constraints of carbon dioxide, nitrogen, methane, methanol, and urea for the virtual power plant

[0046]

[0047] In the formula, represents the mass of carbon dioxide generated by the combined heat and power unit of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide generated by the gas boiler of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide captured by the carbon capture unit of the virtual power plant in the t-th period under scenario s, represents the initial carbon quota of the virtual power plant under scenario s, represents the excess carbon emissions of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide consumed by the synthetic methane of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide consumed by the synthetic methanol of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide consumed by the synthetic urea of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide sequestration of the virtual power plant in the t-th period under scenario s, represents the carbon dioxide storage capacity of the carbon storage device of the virtual power plant in the t-th period under scenario s, represents the carbon dioxide storage capacity of the carbon storage device of the virtual power plant in the (t - 1)-th period under scenario s, represents the mass of nitrogen produced by the pressure swing adsorption nitrogen production device of the virtual power plant in the t-th period under scenario s, represents the mass of nitrogen consumed by the ammonia synthesis of the ammonia manufacturing device of the virtual power plant in the t-th period under scenario s, represents the mass of methane generated by the methane production device of the virtual power plant in the t-th period under scenario s, represents the mass of methane consumed by the combined heat and power unit of the virtual power plant in the t-th period under scenario s, represents the mass of methane consumed by the gas boiler of the virtual power plant in the t-th period under scenario s, represents the mass of methane sold by the virtual power plant in the t-th period under scenario s, represents the mass of methanol produced by the methanol production device of the virtual power plant in the t-th period under scenario s, represents the mass of methanol sold by the virtual power plant in the t-th period under scenario s, represents the mass of urea produced by the urea production device of the virtual power plant in the t-th period under scenario s, represents the mass of urea sold by the virtual power plant in the t-th period under scenario s.

[0048] Furthermore, the specific process of step (3) is as follows:

[0049] (301) Establish the constraints for pressure swing adsorption nitrogen production, methane production, methanol production, ammonia production, and urea production equipment

[0050]

[0051]

[0052] In the formula, represents the mass of nitrogen produced by the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th time period under the scenario s, represents the power-to-gas efficiency of the pressure swing adsorption nitrogen production equipment of the virtual power plant, represents the mass flow rate of air entering the pressure swing adsorption system in the t-th time period under the scenario s, T PSA represents the thermodynamic temperature of the pressure swing adsorption system, Rg AIR represents the gas constant of air, P OUT and P IN represent the outlet pressure and inlet pressure of the pressure swing adsorption system respectively, η m represents the mechanical efficiency of the pressure swing adsorption nitrogen production equipment, represents the isentropic efficiency of the pressure swing adsorption process of the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th time period under the scenario s, Δt represents the time interval, represents the maximum nitrogen production of the pressure swing adsorption nitrogen production equipment of the virtual power plant, represents the ratio of the relative molecular masses of methane and carbon dioxide, represents the ratio of the relative molecular masses of methane and hydrogen, represents the power-to-gas efficiency of the methane production equipment of the virtual power plant, represents the maximum methane production of the methane production equipment of the virtual power plant, represents the ratio of the relative molecular masses of methanol and carbon dioxide, represents the ratio of the relative molecular masses of methanol and hydrogen, represents the power-to-gas efficiency of the methanol production equipment of the virtual power plant, represents the maximum methanol production of the methanol production equipment of the virtual power plant, represents the ratio of the relative molecular masses of ammonia and carbon dioxide, represents the ratio of the relative molecular masses of ammonia and hydrogen, represents the power-to-gas efficiency of the ammonia production equipment of the virtual power plant, represents the maximum ammonia production of the ammonia production equipment of the virtual power plant, represents the ratio of the relative molecular masses of urea and carbon dioxide, represents the ratio of the relative molecular masses of urea and hydrogen, Indicates the urea production efficiency of the urea production equipment of the virtual power plant, Indicates the maximum urea production of the urea production equipment of the power plant;

[0053] (302) Establish constraints for the carbon capture unit, carbon sequestration equipment, electrolyzer, hydrogen fuel cell, combined heat and power unit, and gas boiler

[0054]

[0055] Wherein, Indicates the power consumption rate of the carbon capture unit of the virtual power plant, Indicates the carbon capture rate of the carbon capture unit of the virtual power plant at the t-th time period under scenario s, Indicates the maximum carbon sequestration capacity of the carbon sequestration equipment of the virtual power plant, α ET Indicates the electricity-to-hydrogen conversion efficiency of the electrolyzer of the virtual power plant, Indicates the maximum hydrogen production of the electrolyzer of the virtual power plant, α FC Indicates the power generation efficiency of the hydrogen fuel cell of the virtual power plant, η FCH Indicates the heat conversion efficiency of the hydrogen fuel cell, P FC,MAX Indicates the maximum power generation of the hydrogen fuel cell of the virtual power plant, η GTE Indicates the power generation efficiency of the combined heat and power unit of the virtual power plant, Lmt represents the lower heating value of natural gas, P GT,MAX Indicates the maximum power generation of the combined heat and power unit of the virtual power plant, η GB Indicates the thermal efficiency of the gas boiler of the virtual power plant, H GB,MAX Indicates the maximum heating power of the gas boiler of the virtual power plant, α GT Is the carbon emission coefficient of the combined heat and power unit, α GB Is the carbon emission coefficient of the gas boiler.

[0056] Furthermore, in step (4), a low-carbon flexible operation model of the virtual power plant considering chemical production is written in GAMS software, and the written model is solved to obtain a low-carbon flexible operation plan of the virtual power plant.

[0057] In one embodiment, virtual power plants with 3 different operation modes are used for testing. Virtual power plant 1 is used as a control group. Carbon capture units are installed on virtual power plant 2 based on virtual power plant 1. Carbon capture units are installed on virtual power plant 3 based on virtual power plant 1 and chemical production is considered to produce methane, methanol, and urea. The MIQCP solver on the GAMS platform is used to solve the low-carbon flexible operation model of the virtual power plant considering chemical production to obtain the operation strategy of the virtual power plant.

[0058] Figure 2The operating results of virtual power plant 3 are presented. Between time 8 and time 18, as the power generation of photovoltaic and wind turbine units increases, the electrical power consumed for generating methanol, methane, ammonia, and urea also continuously increases, indicating that virtual power plant 3 has good accommodation capacity for new energy power generation.

[0059] Table 1 compares the impacts of carbon capture and considering chemical production on the operating costs and carbon emissions of each virtual power plant. The operating costs of virtual power plants 2 and 3 are respectively reduced by 364,000 yuan and 457,000 yuan compared with the control group, and the carbon emissions of virtual power plants 2 and 3 are respectively decreased by 30.1% and 33.5% compared with the control group, indicating that the proposed operating method can effectively reduce the operating costs and carbon emissions of virtual power plants.

[0060] Table 1 Comparison of Operating Costs and Carbon Emissions of Virtual Power Plants

[0061]

[0062] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for low-carbon flexible operation of a virtual power plant considering chemical production, characterized in that, The method includes the following steps: Step (1), constructing the objective function of the low-carbon flexible operation model of the virtual power plant considering chemical production; Step (2), constructing the energy and material balance constraints of electricity, hydrogen, heat, carbon dioxide, nitrogen, methane, methanol, and urea for the low-carbon flexible operation model of the virtual power plant considering chemical production; Step (3), constructing the constraints of pressure swing adsorption nitrogen production equipment, methane production equipment, methanol production equipment, ammonia production equipment, urea production equipment, carbon capture unit, carbon sequestration equipment, electrolyzer, hydrogen fuel cell, combined heat and power unit, and gas boiler for the low-carbon flexible operation model of the virtual power plant considering chemical production; Step (4), according to the objective function in Step (1), and combining the constraints in Step (2) and Step (3), solving the low-carbon flexible operation model of the virtual power plant considering chemical production to obtain the operation decision of the virtual power plant.

2. The operation method of a virtual power plant considering chemical production according to claim 1, characterized in that, In Step (1), the objective function of the low-carbon flexible operation model of the virtual power plant considering chemical production is constructed as follows: In the formula, s is the renewable energy output scenario, hereinafter referred to as scenario s, t is the operation period, and t - 1 is the previous operation period of operation period t; Let \(T\) be the total number of operating periods and \(S\) be the total number of renewable energy output scenarios. denotes the occurrence probability of scenario \(s\). denotes the hydrogen selling price in the \(t\)-th period. denotes the hydrogen sales volume of the virtual power plant in the \(t\)-th period under scenario \(s\). denotes the methane selling price in the \(t\)-th period. denotes the mass of methane sold by the virtual power plant in the \(t\)-th period under scenario \(s\). denotes the methanol selling price in the \(t\)-th period. denotes the mass of methanol sold by the virtual power plant in the \(t\)-th period under scenario \(s\). denotes the urea selling price in the \(t\)-th period. denotes the mass of urea sold by the virtual power plant in the \(t\)-th period under scenario \(s\). denotes the carbon dioxide sequestration price in the \(t\)-th period. denotes the carbon dioxide sequestration volume of the virtual power plant in the \(t\)-th period under scenario \(s\), \(\omega\) , FC , , , PV , , , GT , , , , , , ET , , WP , , GB , , , , , , is the unit operation and maintenance cost of the gas boiler of the virtual power plant, \(\omega\) GT is the unit operation and maintenance cost of the combined heat and power unit of the virtual power plant, \(\omega\) WP is the unit operation and maintenance cost of the wind turbine of the virtual power plant, \(\omega\) PV is the unit operation and maintenance cost of the photovoltaic unit of the virtual power plant, \(\omega\) ET is the unit operation and maintenance cost of the electrolyzer of the virtual power plant, \(\omega\) FC is the unit operation and maintenance cost of the hydrogen fuel cell of the virtual power plant. is the unit operation and maintenance cost of the pressure swing adsorption nitrogen production device of the virtual power plant. is the unit operation and maintenance cost of the methane production equipment of the virtual power plant. is the unit operation and maintenance cost of the methanol production equipment of the virtual power plant. is the unit operation and maintenance cost of the urea production equipment of the virtual power plant. denotes the heat production power of the gas boiler of the virtual power plant in the \(t\)-th period under scenario \(s\). denotes the power generation power of the combined heat and power unit of the virtual power plant in the \(t\)-th period under scenario \(s\). <00000​​​​​​​​​​Denote the electric power consumed by the methanol production equipment of the virtual power plant in the t-th period under scenario s. Denote the electric power consumed by the urea production equipment of the virtual power plant in the t-th period under scenario s. Denote the amounts of natural gas purchased by the gas boiler and the combined heat and power unit of the virtual power plant in the t-th period under scenario s, respectively. GAS Denote the purchase price per unit of natural gas. AWP Denote the unit penalty cost for wind curtailment of the virtual power plant. APV Denote the unit penalty cost for PV curtailment of the virtual power plant. Denote the wind curtailment power of the virtual power plant in the t-th period under scenario s. Denote the PV curtailment power of the virtual power plant in the t-th period under scenario s. Denote the electricity purchase price from the power grid at time t. Denote the electricity selling price to the power grid at time t. Denote the electricity purchase power of the virtual power plant in the t-th period under scenario s. C Denote the unit carbon price in the t-th period under scenario s. Denote the excess carbon emissions of the virtual power plant in the t-th period under scenario s.

3. The operation method of a virtual power plant considering chemical production according to claim 2, wherein, The specific process of Step (2) is as follows: (201) Establish the energy balance constraints of electricity, hydrogen, and heat for the virtual power plant; Wherein, represents the electric power consumed by the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th period under scenario s, represents the electric power consumed by the methane production equipment of the virtual power plant in the t-th period under scenario s, represents the electric power consumed by the methanol production equipment of the virtual power plant in the t-th period under scenario s, represents the electric power consumed by the urea production equipment of the virtual power plant in the t-th period under scenario s, represents the electric power consumed by the carbon capture unit of the virtual power plant for carbon dioxide capture in the t-th period under scenario s, represents the electric power consumed by the virtual power plant for carbon dioxide sequestration in the t-th period under scenario s, represents the basic electric load power of the virtual power plant in the t-th period under scenario s, represents the electric power consumed by the electrolyzer of the virtual power plant in the t-th period under scenario s, respectively represent the wind / solar power curtailment of the virtual power plant in the t-th period under scenario s, respectively represent the power generation of the wind and photovoltaic power generation units of the virtual power plant in the t-th period under scenario s, represents the power purchase of the virtual power plant in the t-th period under scenario s, represents the power generation of the cogeneration unit of the virtual power plant in the t-th period under scenario s, represents the power generation of the hydrogen fuel cell of the virtual power plant in the t-th period under scenario s, represents the hydrogen output of the electrolyzer of the virtual power plant in the t-th period under scenario s, represents the hydrogen consumption for methane synthesis of the virtual power plant in the t-th period under scenario s, represents the hydrogen consumption for methanol synthesis of the virtual power plant in the t-th period under scenario s, represents the hydrogen consumption for ammonia synthesis of the virtual power plant in the t-th period under scenario s, represents the hydrogen consumption of the hydrogen fuel cell of the virtual power plant in the t-th period under scenario s, represents the hydrogen sales volume of the virtual power plant in the t-th period under scenario s, represents the hydrogen storage of the virtual power plant in the t-th period under scenario s, represents the hydrogen storage of the virtual power plant in the (t - 1)-th period under scenario s, represents the basic heat load power of the virtual power plant in the t-th period under scenario s, represents the heat production power of the gas boiler of the virtual power plant in the t-th period under scenario s, represents the heat production power of the cogeneration unit of the virtual power plant in the t-th period under scenario s, Denote the heat production power of the combined heat and power unit of the virtual power plant in the t-th period under scenario s. Denote the heat production power of the ammonia production equipment of the virtual power plant in the t-th period under scenario s. (202) Establish the material balance constraints of carbon dioxide, nitrogen, methane, methanol, and urea for the virtual power plant Wherein, represents the mass of carbon dioxide generated by the combined heat and power unit of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide generated by the gas boiler of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide captured by the carbon capture unit of the virtual power plant in the t-th period under scenario s, represents the initial carbon quota of the virtual power plant under scenario s, represents the excess carbon emissions of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide consumed by the synthetic methane of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide consumed by the synthetic methanol of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide consumed by the synthetic urea of the virtual power plant in the t-th period under scenario s, represents the mass of carbon dioxide sequestration of the virtual power plant in the t-th period under scenario s, represents the carbon dioxide storage volume of the carbon storage device of the virtual power plant in the t-th period under scenario s, represents the carbon dioxide storage volume of the carbon storage device of the virtual power plant in the (t - 1)-th period under scenario s, represents the mass of nitrogen produced by the pressure swing adsorption nitrogen production device of the virtual power plant in the t-th period under scenario s, represents the mass of nitrogen consumed by the ammonia synthesis of the ammonia manufacturing device of the virtual power plant in the t-th period under scenario s, represents the mass of methane generated by the methane production device of the virtual power plant in the t-th period under scenario s, represents the mass of methane consumed by the combined heat and power unit of the virtual power plant in the t-th period under scenario s, represents the mass of methane consumed by the gas boiler of the virtual power plant in the t-th period under scenario s, represents the mass of methane sold by the virtual power plant in the t-th period under scenario s, represents the mass of methanol produced by the methanol production device of the virtual power plant in the t-th period under scenario s, represents the mass of methanol sold by the virtual power plant in the t-th period under scenario s, represents the mass of urea produced by the urea production device of the virtual power plant in the t-th period under scenario s, represents the mass of urea sold by the virtual power plant in the t-th period under scenario s.

4. The operation method of a virtual power plant considering chemical production according to claim 1, characterized in that The specific process of Step (3) is as follows: (301) Establish the constraints of pressure swing adsorption nitrogen production, methane production, methanol production, ammonia production, and urea production equipment Wherein, represents the mass of nitrogen produced by the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th period under the scenario s, represents the power-to-gas efficiency of the pressure swing adsorption nitrogen production equipment of the virtual power plant, represents the air mass flow rate entering the pressure swing adsorption system in the t-th period under the scenario s, T PSA represents the thermodynamic temperature of the pressure swing adsorption system, Rg AIR represents the gas constant of air, P OUT and P IN represent the outlet pressure and inlet pressure of the pressure swing adsorption system respectively, η m represents the mechanical efficiency of the pressure swing adsorption nitrogen production equipment, represents the isentropic efficiency of the pressure swing adsorption process of the pressure swing adsorption nitrogen production equipment of the virtual power plant in the t-th period under the scenario s, Δt represents the time interval, represents the maximum nitrogen production of the pressure swing adsorption nitrogen production equipment of the virtual power plant, represents the ratio of the relative molecular masses of methane and carbon dioxide, represents the ratio of the relative molecular masses of methane and hydrogen, represents the power-to-gas efficiency of the methane production equipment of the virtual power plant, represents the maximum methane production of the methane production equipment of the virtual power plant, represents the ratio of the relative molecular masses of methanol and carbon dioxide, represents the ratio of the relative molecular masses of methanol and hydrogen, represents the power-to-gas efficiency of the methanol production equipment of the virtual power plant, represents the maximum methanol production of the methanol production equipment of the virtual power plant, represents the ratio of the relative molecular masses of ammonia and carbon dioxide, represents the ratio of the relative molecular masses of ammonia and hydrogen, represents the power-to-gas efficiency of the ammonia production equipment of the virtual power plant, represents the maximum ammonia production of the ammonia production equipment of the virtual power plant, represents the ratio of the relative molecular masses of urea and carbon dioxide, represents the ratio of the relative molecular masses of urea and hydrogen, represents the urea production efficiency of the urea production equipment of the virtual power plant, represents the maximum urea production of the urea production equipment of the power plant; (302) Establish the constraints of carbon capture unit, carbon sequestration equipment, electrolyzer, hydrogen fuel cell, combined heat and power unit, and gas boiler Where, represents the electricity consumption rate of the carbon capture unit of the virtual power plant, represents the carbon capture rate of the carbon capture unit of the virtual power plant in the tth period under scenario s, represents the maximum carbon storage capacity of the carbon storage equipment of the virtual power plant, α ET represents the power-to-hydrogen efficiency of the electrolyzer in the virtual power plant, represents the maximum hydrogen production of the electrolyzer of the virtual power plant, α FC represents the power generation efficiency of the hydrogen fuel cell in the virtual power plant, η FCH Represents the thermal conversion efficiency of hydrogen fuel cells, P FC,MAX represents the maximum power generation of hydrogen fuel cells in the virtual power plant, η GTE represents the power generation efficiency of the combined heat and power unit of the virtual power plant, Lmt represents the lower calorific value of natural gas, P GT,MAX represents the maximum power generation capacity of the combined heat and power unit of the virtual power plant, η GB represents the thermal efficiency of the gas boiler in the virtual power plant, H GB,MAX represents the maximum heating power of the gas boiler of the virtual power plant, α GT is the carbon emission coefficient of the cogeneration unit, α GB is the carbon emission coefficient of the gas boiler.

5. The operating method of a virtual power plant considering chemical production according to claim 1, characterized in that, In Step (4), write the low-carbon flexible operation model of the virtual power plant considering chemical production in GAMS software, and solve the compiled model to obtain the low-carbon flexible operation plan of the virtual power plant.

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