Off-grid comprehensive energy hydrogen production system planning method and device oriented to hydrogen demand

Abstract

The invention relates to an off-grid comprehensive energy hydrogen production system planning method and device for a hydrogen demand, and the method comprises the steps: constructing a hydrogen production-storage-use full-process model which comprises an off-grid hydrogen production section model, a compression buffer section model and an industrial synthesis section model; the off-grid hydrogen production section model comprises a water electrolysis hydrogen production model, a biomass gasification hydrogen production model and a natural gas reforming hydrogen production model, the compression buffer section model comprises a compressor model and a hydrogen storage tank model, and the industrial synthesis section model comprises an industrial hydrogen load model; a hydrogen production system double-layer planning model comprising an upper layer planning model and a lower layer operation model is constructed, the upper layer planning model takes the minimum construction and operation cost, the minimum carbon emission and the maximum total hydrogen production amount as the target, and the lower layer operation model takes the minimum operation cost as the target; and solving the bilayer planning model of the hydrogen production system to obtain an optimal planning scheme. The carbon emission in the hydrogen production process is reduced while the industrial requirements for stability and reliability of hydrogen are met.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a planning method and device for an off-grid integrated energy hydrogen production system oriented to hydrogen demand. Background Art

[0002] Hydrogen is considered to be an ideal secondary energy source due to its abundant sources, high combustion calorific value, and clean and pollution-free use. The downstream industries of hydrogen include chemical synthesis, fuel cells, hydrogen transportation, etc. Limited by the maturity of technology, the main consumer terminals of hydrogen energy are chemical industries such as ammonia and methanol synthesis. Constrained by the process such as the thermal inertia of the synthesis tower, the load regulation capacity of chemical synthesis is limited, which puts high demands on the stability of hydrogen input. At present, the main source of industrial hydrogen is fossil energy represented by coal and natural gas reforming. The hydrogen production is stable and controllable, but it produces a large amount of carbon emissions. As the country promotes the transformation of synthetic ammonia, synthetic methanol, refining, coal-to-oil and gas and other industries from high-carbon processes to low-carbon processes, the use of renewable energy to replace fossil energy to produce hydrogen as an important means to reduce carbon emissions has received widespread attention.

[0003] Renewable energy hydrogen production can be divided into two types: grid-connected and off-grid. The grid-connected renewable energy hydrogen production system is supported by the external power grid, and the hydrogen output is relatively stable, but the grid connection cost is high, and in order to reduce the system regulation pressure of the power grid, its operation mode is strictly controlled. In addition, since the grid-connected system uses grid electricity to produce hydrogen, its green certification is difficult. The off-grid renewable energy hydrogen production system lacks the support of the external power grid. Due to the volatility of renewable energy, it is difficult to achieve stable hydrogen production. In order to ensure the safety and stability of chemical synthesis, a large number of hydrogen storage devices need to be configured between the hydrogen production section and the chemical synthesis section, which significantly increases the equipment investment cost of the system. At the same time, large-scale storage of flammable and explosive hydrogen also poses a threat to safety. Therefore, it is necessary to explore a low-carbon off-grid hydrogen production system that can achieve a balance between hydrogen production and use. The integration of multiple hydrogen production technologies has been proven to be a means to combine the advantages of different hydrogen production routes. By rationally planning the hydrogen production system and considering the complementary utilization relationship between different technologies, it is expected to reduce carbon emissions in the hydrogen production process while meeting the industrial demand for hydrogen stability and reliability. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects and problems existing in the prior art, and to provide a planning method and device for an off-grid integrated energy hydrogen production system for hydrogen demand, which reduces carbon emissions in the hydrogen production process while meeting the industrial demand for stability and reliability of hydrogen use.

[0005] To achieve the above objectives, the technical solution of the present invention is: a planning method for an off-grid integrated energy hydrogen production system oriented to hydrogen demand, comprising:

[0006] Constructing a full-process model of hydrogen production-storage-use of off-grid comprehensive energy, including an off-grid hydrogen production section model, a compression buffer section model and an industrial synthesis section model, wherein the off-grid hydrogen production section model includes a water electrolysis hydrogen production model, a biomass gasification hydrogen production model and a natural gas reforming hydrogen production model, the compression buffer section model includes a compressor model and a hydrogen storage tank model, and the industrial synthesis section model includes an industrial hydrogen load model;

[0007] Constructing a two-level planning model for a hydrogen production system including an upper-level planning model and a lower-level operation model, wherein the upper-level planning model aims to minimize the construction and operation costs of the hydrogen production system, minimize carbon emissions, and maximize the total hydrogen production, and the lower-level operation model aims to minimize the operation cost of the hydrogen production system;

[0008] Solve the two-level planning model of the hydrogen production system to obtain the optimal planning solution.

[0009] The natural gas reforming hydrogen production model is:

[0010]

[0011] ΔX s =X SR -X FR ;

[0012]

[0013] In the formula, is the biomass consumption at time t; is the relative molecular mass of Fe3O4 after complete oxidation; is the relative molecular mass of Fe3O4; is the output of FeO at time t; is the output of Fe at time t; X SR and X FR are the conversion rates of oxygen carriers at the outlets of the steam reactor and the fuel reactor, respectively; ΔX s is the difference in conversion rate of oxygen carriers at the outlet of the steam reactor and the fuel reactor; is the output of Fe3O4 at time t; is the output of hydrogen produced by natural gas reforming at time t; is the hydrogen production coefficient in the reaction; is the natural gas consumption at time t; is the oxygen production coefficient in the reaction; is the oxygen consumption at time t.

[0014] The compressor model is:

[0015]

[0016] Where P t comp is the power consumption of the compressor at time t; is the specific heat capacity constant of hydrogen; is the hydrogen input flow rate at time t; T in is the input hydrogen temperature; γ is the hydrogen isentropic index; η comp is the compressor working efficiency; k comp is the compression ratio; The maximum power consumption of the compressor.

[0017] The hydrogen storage tank model is:

[0018]

[0019] In the formula, is the hydrogen storage capacity of the hydrogen storage tank at time t; is the hydrogen storage capacity of the hydrogen storage tank at time t-1; is the hydrogen input flow rate at time t; is the industrial hydrogen load at time t; η in and η out efficiency of hydrogen injection and release; and is the hydrogen storage capacity of the hydrogen storage tank at the first and last moment of the day; m HS_max is the maximum hydrogen storage capacity of the hydrogen storage tank.

[0020] The industrial hydrogen load model is:

[0021]

[0022] Where n H_load_min and n H_load_max are the minimum and maximum values ​​of industrial hydrogen load; and is the maximum decreasing rate and the maximum increasing rate of industrial hydrogen load; d a (τ) is a binary variable. When the industrial hydrogen load changes, d a (τ) is 1, when the industrial hydrogen load remains unchanged, d a (τ) is 0; D is the minimum interval for adjusting the industrial hydrogen load; T is the entire scheduling cycle; M is a positive number; d a (t) is the industrial hydrogen load variable, indicating whether the industrial hydrogen load changes.

[0023] The upper-level planning model is:

[0024]

[0025]

[0026] The lower layer operation model is:

[0027]

[0028] In the formula, for construction and operation costs; is the annualized investment cost; For maintenance costs; The operating cost for the whole year; is the construction capacity of equipment i; is the construction cost of equipment i; r is the discount rate; τ i is the life cycle of device i; is the maintenance factor of equipment i; is the upper limit of the installation capacity of device i; I is the number of device types; C carbon is the carbon emission; T is the entire scheduling period; is the carbon emission factor of biomass transportation; is the biomass consumption at time t; is the carbon emission coefficient of natural gas; is the natural gas consumption at time t; is the total hydrogen production; is the output of hydrogen produced by electrolysis of water at time t; is the output of hydrogen produced by natural gas reforming at time t; is the output of hydrogen produced by biomass gasification at time t; is the unit cost of biomass; is the unit cost of natural gas.

[0029] The method of solving the hydrogen production system double-level programming model to obtain the optimal programming scheme includes:

[0030] First, the upper-level planning model is solved using the NSGA-2 algorithm, and the lower-level operation model is solved using a commercial solver. The solution of the upper-level planning model is passed to the lower-level operation model, and the solution of the lower-level operation model is passed to the upper-level planning model. The upper and lower layers are iterated back and forth to solve the optimal planning scheme set. The weights of the three objectives of construction and operation costs, carbon emissions, and total hydrogen production are calculated based on the hierarchical analysis method, and then the TOPSIS method is used to select the optimal planning scheme.

[0031] An off-grid integrated energy hydrogen production system planning device for hydrogen demand, the device is applied to the above-mentioned method, the device comprises:

[0032] A hydrogen production-storage-use full-process model construction module is used to construct a hydrogen production-storage-use full-process model of an off-grid comprehensive energy source including an off-grid hydrogen production section model, a compression buffer section model, and an industrial synthesis section model. The off-grid hydrogen production section model includes a water electrolysis hydrogen production model, a biomass gasification hydrogen production model, and a natural gas reforming hydrogen production model. The compression buffer section model includes a compressor model and a hydrogen storage tank model. The industrial synthesis section model includes an industrial hydrogen load model.

[0033] A two-layer planning model construction module for a hydrogen production system is used to construct a two-layer planning model for a hydrogen production system including an upper-layer planning model and a lower-layer operation model. The upper-layer planning model aims to minimize the construction and operation costs of the hydrogen production system, minimize carbon emissions, and maximize the total hydrogen production. The lower-layer operation model aims to minimize the operation cost of the hydrogen production system.

[0034] The optimal planning solution module is used to solve the double-layer planning model of the hydrogen production system to obtain the optimal planning solution.

[0035] An off-grid integrated energy hydrogen production system planning device for hydrogen demand, comprising a memory and a processor;

[0036] The memory is used to store computer program code and transmit the computer program code to the processor;

[0037] The processor is used to execute the method according to the instructions in the computer program code.

[0038] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] In the off-grid comprehensive energy hydrogen production system planning method and device for hydrogen demand of the present invention, the requirements for the stability of hydrogen production for industrial synthesis hydrogen are taken into account, and the cost increase and safety hazards caused by the construction of a large number of hydrogen storage tanks are avoided. The present invention combines three types of hydrogen production technologies: water electrolysis hydrogen production, biomass gasification hydrogen production, and natural gas reforming hydrogen production, realizes the complementary advantages of the three types of technologies, and improves the overall efficiency of the hydrogen production system. At the same time, the low carbon of water electrolysis hydrogen production and biomass gasification hydrogen production and the stable and controllable natural gas hydrogen production are utilized to achieve relatively green and stable controllable hydrogen production. In addition, the present invention combines intelligent algorithms with optimization solvers to achieve the solution of multi-objective mixed integer nonlinear programming problems, overcomes the problem that traditional solvers cannot directly solve, obtains the optimal planning scheme set, and selects the optimal planning scheme through the AHP+TOPSIS analysis method. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of a method for planning an off-grid integrated energy hydrogen production system oriented to hydrogen demand of the present invention.

[0042] Figure 2 It is a full-process model diagram of hydrogen production-storage-use of off-grid integrated energy in an embodiment of the present invention.

[0043] Figure 3 It is a structural block diagram of a planning device for an off-grid comprehensive energy hydrogen production system oriented to hydrogen demand of the present invention.

[0044] Figure 4 It is a structural block diagram of an off-grid comprehensive energy hydrogen production system planning device for hydrogen demand according to the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0046] See also Figure 1 , a planning method for an off-grid integrated energy hydrogen production system oriented to hydrogen demand, comprising:

[0047] S1. Constructing a full-process model of hydrogen production, storage and use of off-grid comprehensive energy, including an off-grid hydrogen production section model, a compression buffer section model and an industrial synthesis section model. The off-grid hydrogen production section model includes a water electrolysis hydrogen production model, a biomass gasification hydrogen production model and a natural gas reforming hydrogen production model. The compression buffer section model includes a compressor model and a hydrogen storage tank model. The industrial synthesis section model includes an industrial hydrogen load model.

[0048] S2. Construct a two-level planning model for a hydrogen production system including an upper-level planning model and a lower-level operation model, wherein the upper-level planning model aims to minimize the construction and operation costs of the hydrogen production system, minimize carbon emissions, and maximize the total hydrogen production, and the lower-level operation model aims to minimize the operation cost of the hydrogen production system;

[0049] S3. Solve the two-level planning model of the hydrogen production system to obtain the optimal planning solution.

[0050] As for the off-grid hydrogen production system, there are two issues that need further study: (1) how to ensure the stability of hydrogen production to meet actual industrial needs; (2) how to combine different hydrogen production technologies and improve the efficiency of hydrogen production through technical complementarity. Figure 2 The full process model of hydrogen production, storage and use of off-grid integrated energy is shown, and a planning method for an integrated energy hydrogen production system that takes into account the actual industrial hydrogen demand and combines multiple hydrogen production technologies is provided.

[0051] Furthermore, the off-grid hydrogen production section equipment includes new energy power generation equipment, proton exchange membrane electrolyzer, biomass gasifier, natural gas reforming equipment, energy storage power station, oxygen storage tank, and natural gas storage tank. The new energy power station, energy storage power station, oxygen storage tank, and natural gas storage tank are all conventional models and will not be repeated here. The present invention combines three types of hydrogen production technologies: water electrolysis hydrogen production, biomass gasification hydrogen production, and natural gas reforming hydrogen production, to achieve a relatively stable hydrogen output, and considers the coupling utilization of oxygen, a by-product of water electrolysis hydrogen production, and natural gas, a by-product of biomass gasification hydrogen production, to construct an off-grid hydrogen production section model, specifically:

[0052] A1. Proton exchange membrane water electrolysis hydrogen production model

[0053] The proton exchange membrane water electrolysis device has the advantages of fast start and stop, flexible power adjustment, and high energy utilization efficiency. It is suitable for combination with renewable energy such as wind and solar. The power consumption of water electrolysis can be expressed as:

[0054]

[0055] Where P t WE is the power consumed by electrolyzing water at time t; N cell is the number of electrolysis chambers; and is the voltage and current of the electrolytic cell at time t; E, and are the Nernst potential of the electrolytic cell, the Ohmic overpotential of the electrolytic cell at time t, and the activation overpotential of the electrolytic cell at time t; U rev is the reversible voltage; R is the ideal gas constant; T cell is the working temperature of the electrolytic cell; F is the Faraday coefficient; and is the partial pressure of hydrogen and oxygen; is the activity of water; α an and α cat are the charge transfer coefficients of the anode and cathode respectively; i an and i cat are the current densities at the anode and cathode; is the current density at time t.

[0056] The hydrogen and oxygen production from water electrolysis can be expressed as:

[0057]

[0058] In the formula, and is the production of hydrogen and oxygen from water electrolysis at time t; h F is the Faraday efficiency.

[0059] A2. Biomass gasification hydrogen production model

[0060] Biomass gasification hydrogen production is the process of converting biomass particles into hydrogen-containing combustible gas in a gasifying agent. Oxygen, a byproduct produced during the electrolysis of water to produce hydrogen, can be used as a gasifying agent to improve the concentration and energy efficiency of hydrogen produced from biomass. With the participation of oxygen as a gasifying agent, the overall gasification reaction formula is:

[0061]

[0062] In the formula, CH 1.44 O 0.66 is the chemical expression of biomass; is the oxygen consumption coefficient; c CO-BG , are the coefficients for the products of hydrogen, carbon monoxide, carbon dioxide, water, and methane.

[0063] According to the principles of element balance, equilibrium constant and heat balance equation, the equation describing the relationship between biomass, oxygen and generated gas is:

[0064]

[0065] In the formula, is the biomass consumption at time t; is the output of hydrogen produced by biomass gasification at time t; is the oxygen consumption at time t; is the natural gas production at time t; is the carbon dioxide production at time t.

[0066] A3. Natural gas reforming hydrogen production model

[0067] Compared with the first two technologies, natural gas reforming to produce hydrogen is more flexible, and the hydrogen output can vary with fluctuations in demand, but it will bring high carbon emissions. In a pure oxygen environment, the output of natural gas reforming to produce hydrogen is increased and impurities are reduced.

[0068] The natural gas reforming plant consists of two interconnected reactors, the fuel reactor and the steam reactor. The oxygen carriers in the fuel reactor are reduced to low-valent oxides (MeO n ) or simple substances (Me), generating H2O and CO2. In a steam reactor, MeO n Or Me is partially oxidized by H2O, and the generated gas is condensed to obtain high-purity H2. In addition, the reduced oxygen carrier is completely oxidized by oxygen. In the present invention, natural gas (CH4) is used as fuel and iron oxide is used as oxygen carrier. The reaction process is as follows:

[0069]

[0070] ΔX s =X SR -X FR ;

[0071]

[0072] In the formula, is the biomass consumption at time t; is the relative molecular mass of Fe3O4 after complete oxidation; is the relative molecular mass of Fe3O4; is the output of FeO at time t; is the output of Fe at time t; X SR and X FR are the conversion rates of oxygen carriers at the outlets of the steam reactor and the fuel reactor, respectively; ΔX S is the difference in conversion rate of oxygen carriers at the outlet of the steam reactor and the fuel reactor; is the output of Fe3O4 at time t; is the output of hydrogen produced by natural gas reforming at time t; is the hydrogen production coefficient in the reaction; is the natural gas consumption at time t; is the oxygen production coefficient in the reaction; is the oxygen consumption at time t.

[0073] A4. Coupling constraints between matter and energy

[0074] Oxygen, a byproduct of hydrogen production from water electrolysis, can be used for hydrogen production from biomass gasification and hydrogen production from natural gas reforming to increase hydrogen production and reaction efficiency. Natural gas, a byproduct of hydrogen production from biomass gasification, can be used as fuel for reforming hydrogen production.

[0075] Coupling constraints for oxygen:

[0076]

[0077] In the formula, is the amount of oxygen supplied to the oxygen storage tank by the water electrolysis hydrogen production equipment at time t; is the amount of oxygen supplied from the water electrolysis hydrogen production equipment to the biomass gasification hydrogen production equipment at time t; is the amount of oxygen supplied from the water electrolysis hydrogen production equipment to the natural gas reforming hydrogen production equipment at time t; is the amount of oxygen supplied from the oxygen storage tank to the biomass gasification hydrogen production equipment at time t; It is the amount of oxygen supplied from the oxygen storage tank to the natural gas reforming hydrogen production equipment at time t.

[0078] Natural gas coupling constraints:

[0079]

[0080] In the formula, is the amount of natural gas delivered from the biomass gasification hydrogen production equipment to the natural gas reforming hydrogen production equipment at time t; is the amount of natural gas delivered from the biomass gasification hydrogen production equipment to the natural gas storage tank at time t; It is the amount of natural gas delivered from the natural gas storage tank to the natural gas reforming hydrogen production equipment at time t.

[0081] Total hydrogen production:

[0082]

[0083] In the formula, is the total hydrogen production at time t.

[0084] The electricity required for water electrolysis and compressors all comes from wind and solar power generation or energy storage equipment:

[0085]

[0086] Where P t pv and P t wt is the actual output of photovoltaic and wind power at time t; P t es_ch and P t es_dis is the charging and discharging power of energy storage at time t; P t WE is the power consumed by electrolyzing water at time t; P t comp is the power of the compressor at time t.

[0087] The present invention combines three types of hydrogen production technologies, namely, water electrolysis hydrogen production, biomass gasification hydrogen production, and natural gas reforming hydrogen production, to achieve complementary advantages among the three types of technologies. It utilizes oxygen, a by-product of water electrolysis, and natural gas, a by-product of biogasification, to improve the overall efficiency of the hydrogen production system. It utilizes the low carbon nature of water electrolysis hydrogen production and biomass gasification hydrogen production and the stable and controllable nature of natural gas hydrogen production to achieve relatively green, stable and controllable hydrogen production.

[0088] Furthermore, since the industrial synthesis process requires a high pressure of raw gas, the pressure of hydrogen produced by the hydrogen production section is insufficient, and the two cannot be directly coupled. In addition, the load regulation speed of the industrial synthesis section is slow, and the hydrogen production of the off-grid hydrogen production system usually has a certain volatility. A buffer storage section is required between the two to meet the stability requirements of industrial hydrogen use.

[0089] In order to facilitate hydrogen storage and meet the pressure requirements of industrial hydrogen, a compressor is needed to compress hydrogen into high-pressure hydrogen. The compressor model is:

[0090]

[0091] The compressor needs to work below the maximum power:

[0092]

[0093] In the formula, R t comp is the power consumption of the compressor at time t; is the specific heat capacity constant of hydrogen; is the hydrogen input flow rate at time t; T in is the input hydrogen temperature; γ is the hydrogen isentropic index; η comp is the compressor working efficiency; k comp is the compression ratio; The maximum power consumption of the compressor.

[0094] Furthermore, the hydrogen storage tank model is:

[0095]

[0096] The amount of hydrogen in the hydrogen storage tank should be kept balanced within a day:

[0097]

[0098] The hydrogen storage tank must also meet capacity constraints:

[0099]

[0100] In the formula, is the hydrogen storage capacity of the hydrogen storage tank at time t; is the hydrogen storage capacity of the hydrogen storage tank at time t-1; is the hydrogen input flow rate at time t; is the industrial hydrogen load at time t; η in and η out efficiency of filling and releasing hydrogen storage tanks; and is the hydrogen storage capacity of the hydrogen storage tank at the first and last moment of the day; m HS_max is the maximum hydrogen storage capacity of the hydrogen storage tank.

[0101] Furthermore, the industrial hydrogen load model is:

[0102] Since the load regulation capacity of the industrial synthesis section is limited, hydrogen is used as the input raw material. The hydrogen input needs to be ensured to be within the load range allowed by industrial synthesis:

[0103]

[0104] Since the load adjustment rate of chemical synthesis is slow, it is necessary to constrain the rate change of hydrogen input:

[0105]

[0106] In order to ensure the safety and stability of industrial synthesis, the load can only be adjusted once within a certain period of time. Therefore, the hydrogen input can only be changed once within a certain period of time:

[0107]

[0108] Where n H_load_min and n H_load_max are the minimum and maximum values ​​of industrial hydrogen load; and is the maximum decreasing rate and the maximum increasing rate of industrial hydrogen load; d a (τ) is a binary variable. When the industrial hydrogen load changes, d a (τ) is 1, when the industrial hydrogen load remains unchanged, d a (τ) is 0; D is the minimum interval for adjusting the industrial hydrogen load; T is the entire scheduling cycle; M is a large positive number; d a (t) is the industrial hydrogen load variable, indicating whether the industrial hydrogen load changes.

[0109] Unlike traditional planning that only considers the cost of hydrogen production, the present invention constructs a full-process model of hydrogen production-storage-use with off-grid comprehensive energy that takes into account the hydrogen production section, compression buffer section, and industrial synthesis section. It also takes into account the requirement for stable hydrogen production for industrial synthesis of hydrogen, and avoids the cost increase and safety hazards caused by the construction of a large number of hydrogen storage tanks.

[0110] Furthermore, in the two-level planning model of the hydrogen production system, the upper-level planning model solves the capacity optimization configuration problem of the hydrogen production equipment, and the lower-level operation model solves the operation scheduling problem of the hydrogen production equipment.

[0111] The upper-level planning model is a multi-objective planning model, and its objective functions are the system construction and operation costs, carbon emissions, and total hydrogen production.

[0112] Objective 1: Construction and operation costs of hydrogen production systems

[0113] The construction and operation costs of the hydrogen production system include the annual investment cost, maintenance cost, and operation cost of the equipment, specifically:

[0114]

[0115] Due to the actual installation site size limitation, the installation capacity of the equipment has an upper limit, specifically:

[0116]

[0117] In the formula, for construction and operation costs; is the annualized investment cost; For maintenance costs; The operating cost for the whole year; is the construction capacity of equipment i; is the construction cost of equipment i; r is the discount rate; τ i is the life cycle of device i; is the maintenance factor of equipment i; is the upper limit of the installation capacity of device i, and I is the number of device types.

[0118] Target 2: Carbon Emissions

[0119] Carbon emissions are an important indicator of environmental benefits. Carbon emissions from hydrogen production systems mainly come from natural gas combustion and biomass transportation, specifically:

[0120]

[0121] In the formula, C carbon is the carbon emission; T is the entire scheduling period; is the carbon emission factor of biomass transportation; is the biomass consumption at time t; is the carbon emission coefficient of natural gas; is the natural gas consumption at time t.

[0122] Goal 3: Total hydrogen production

[0123] The hydrogen production system needs to produce as much hydrogen as possible to meet industrial needs in order to achieve higher economic benefits. Specifically:

[0124]

[0125] In the formula, is the total hydrogen production; is the output of hydrogen produced by electrolysis of water at time t; is the output of hydrogen produced by natural gas reforming at time t, is the hydrogen production from biomass gasification at time t.

[0126] The lower-level operation model mainly includes the biomass raw material cost and the natural gas raw material cost. The lower-level operation model is:

[0127]

[0128] In the formula, is the unit cost of biomass; is the unit cost of natural gas.

[0129] Furthermore, the optimal planning scheme is obtained by solving the two-level planning model of the hydrogen production system, including:

[0130] First, the upper-level planning model is solved using the NSGA-2 algorithm, and the lower-level operation model is solved using a commercial solver. The solution of the upper-level planning model is passed to the lower-level operation model, and the solution of the lower-level operation model is passed to the upper-level planning model. The upper and lower layers are iterated back and forth to solve the optimal planning scheme set. The weights of the three objectives of construction and operation costs, carbon emissions, and total hydrogen production are calculated based on the hierarchical analysis method, and then the TOPSIS method is used to select the optimal planning scheme.

[0131] The solution to the multi-objective optimization problem is a feasible solution set composed of the Pareto front. The multi-objective optimization problem to be solved by the present invention has the characteristics of nonlinearity and discreteness. It is a multi-objective mixed integer nonlinear programming problem and cannot be solved directly using a commercial solver. Therefore, the present invention combines an intelligent algorithm with a solver. The upper layer uses the NSGA-2 algorithm to make decisions on planning variables, and the lower layer uses the commercial solver gurobi / Cplex to solve. The upper and lower layers iterate to solve the multi-objective optimization problem.

[0132] The time scale of the upper-level planning model is one year, the time scale of the lower-level operation model is one day, and the scheduling interval is 1 hour. The upper layer passes the planned new energy installed capacity, hydrogen production equipment installed capacity, energy storage and other equipment installed capacity to the lower layer, and the lower layer uses the solver to quickly solve and return the results to the upper layer. The upper layer sorts the various planning schemes, generates new planning schemes through cross-mutation operations, and passes them to the lower layer for calculation again, iterating back and forth to obtain the optimal planning scheme set.

[0133] To ensure that the calculation results are representative for the whole year, the lower layer sets up multiple typical days for calculation based on the stochastic optimization theory for the wind and solar power output curves, and performs weighted summation of the operating results based on the probability of occurrence of typical days and passes them to the upper layer.

[0134] Generation and reduction method of typical wind and solar days: Based on the generative adversarial network scenario generation method, 3000 sets of 24-hour wind and solar output data are generated. The synchronous back-substitution elimination method is used to cluster the 3000 sets of generated wind and solar data. The number of clusters is selected as 4, and typical scenes and the probability of occurrence of each typical scene are obtained.

[0135] The optimal planning scheme selection strategy based on AHP+TOPSIS

[0136] Since the multi-objective optimization problem will eventually form an optimal Pareto solution set, each solution is a feasible planning scheme. In order to formulate the optimal planning scheme, it is necessary to select the Pareto solution set again.

[0137] The analytic hierarchy process (AHP) is a decision analysis method that combines quantitative and qualitative methods. It is often used in multi-attribute decision problems, such as enterprise selection of investment projects, product design, etc. The weights of the three objectives can be obtained with the help of the AHP method. The implementation method is as follows:

[0138] The AHP method requires that the various influencing factors that need to be compared be listed first, and then the influencing factors be compared and analyzed pairwise. The comparison results are used to form a relative importance matrix. After checking the consistency of the calculation results, the weight of each indicator is calculated.

[0139] 1) Compare the experts’ scores on each indicator and form a matrix to obtain the weight of each indicator evaluated by each expert.

[0140] 2) Repeat the previous step to form a matrix of all experts’ indicator weights:

[0141]

[0142] 3) Calculate the correlation coefficient matrix

[0143]

[0144] Correlation coefficient matrix:

[0145]

[0146] 4) Eliminate scores that differ greatly from those of other experts

[0147]

[0148] If d i The larger the value is, the more consistent the expert's opinions are with those of other experts; otherwise, the expert's opinions are inconsistent with those of other experts.

[0149] 5) Calculate the average value of the column vector of the weight matrix after screening is the weight value of the evaluation index, and

[0150] Through the above method, the weights of the three objectives of off-grid hydrogen production system construction and operation cost, carbon emissions, and total hydrogen production can be obtained.

[0151] The TOPSIS method is widely used to select the optimal solution according to the distance between the ideal solution and the negative ideal solution. In the present invention, the TOPSIS method is adopted, and the weight of each evaluation target is set according to the weight obtained by the AHP method, and the optimal ideal solution and negative ideal solution results based on the TOPSIS method are obtained by weighted calculation.

[0152] The present invention combines intelligent algorithms with optimization solvers to achieve the solution of multi-objective mixed integer nonlinear programming problems, overcomes the problem that traditional solvers cannot solve directly, obtains the optimal planning scheme set, and selects the optimal planning scheme through the AHP+TOPSIS analysis method.

[0153] See also Figure 3 The present invention also provides an off-grid comprehensive energy hydrogen production system planning device for hydrogen demand, which is applied to the above-mentioned off-grid comprehensive energy hydrogen production system planning method for hydrogen demand, and the device includes:

[0154] A hydrogen production-storage-use full-process model construction module is used to construct a hydrogen production-storage-use full-process model of an off-grid comprehensive energy source including an off-grid hydrogen production section model, a compression buffer section model, and an industrial synthesis section model. The off-grid hydrogen production section model includes a water electrolysis hydrogen production model, a biomass gasification hydrogen production model, and a natural gas reforming hydrogen production model. The compression buffer section model includes a compressor model and a hydrogen storage tank model. The industrial synthesis section model includes an industrial hydrogen load model.

[0155] A two-layer planning model construction module for a hydrogen production system is used to construct a two-layer planning model for a hydrogen production system including an upper-layer planning model and a lower-layer operation model. The upper-layer planning model aims to minimize the construction and operation costs of the hydrogen production system, minimize carbon emissions, and maximize the total hydrogen production. The lower-layer operation model aims to minimize the operation cost of the hydrogen production system.

[0156] The optimal planning solution module is used to solve the double-layer planning model of the hydrogen production system to obtain the optimal planning solution.

[0157] See also Figure 4 , the present invention also provides an off-grid comprehensive energy hydrogen production system planning device for hydrogen demand, including a memory and a processor;

[0158] The memory is used to store computer program code and transmit the computer program code to the processor;

[0159] The processor is used to execute the above-mentioned off-grid integrated energy hydrogen production system planning method for hydrogen demand according to the instructions in the computer program code.

[0160] The present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program implements the above-mentioned off-grid integrated energy hydrogen production system planning method for hydrogen demand.

[0161] Generally speaking, the computer instructions for implementing the method of the present invention may be carried in any combination of one or more computer-readable storage media. Non-transitory computer-readable storage media may include any computer-readable media, except for the signal itself that is temporarily propagating.

[0162] The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EKROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, device, or device.

[0163] Computer program code for performing the operation of the present invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages, in particular, Python suitable for neural network computing and platform frameworks based on TensorFlow, PyTorch, etc. can be used. The program code can be executed entirely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer or to an external computer (for example, using an Internet service provider to connect via the Internet) through any type of network, including a local area network (LAN) or a wide area network (WAN).

[0164] The above-mentioned devices and non-temporary computer-readable storage media can be found in the specific description of a planning method for an off-grid integrated energy hydrogen production system for hydrogen demand and its beneficial effects, which will not be repeated here.

[0165] Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A planning method for an off-grid integrated energy hydrogen production system for hydrogen demand, characterized in that: include: Constructing a full-process model of hydrogen production-storage-use of off-grid comprehensive energy, including an off-grid hydrogen production section model, a compression buffer section model and an industrial synthesis section model, wherein the off-grid hydrogen production section model includes a water electrolysis hydrogen production model, a biomass gasification hydrogen production model and a natural gas reforming hydrogen production model, the compression buffer section model includes a compressor model and a hydrogen storage tank model, and the industrial synthesis section model includes an industrial hydrogen load model; Constructing a two-level planning model for a hydrogen production system including an upper-level planning model and a lower-level operation model, wherein the upper-level planning model aims to minimize the construction and operation costs of the hydrogen production system, minimize carbon emissions, and maximize the total hydrogen production, and the lower-level operation model aims to minimize the operation cost of the hydrogen production system; Solve the two-level planning model of the hydrogen production system to obtain the optimal planning solution.

2. The off-grid comprehensive energy hydrogen production system planning method for hydrogen demand according to claim 1 is characterized in that: The natural gas reforming hydrogen production model is: In the formula, is the biomass consumption at time t; is the relative molecular mass of Fe3O4 after complete oxidation; is the relative molecular mass of Fe3O4; is the output of FeO at time t; is the output of Fe at time t; X SR and X FR are the conversion rates of oxygen carriers at the outlets of the steam reactor and the fuel reactor, respectively; ΔX S is the difference in conversion rate of oxygen carriers at the outlet of the steam reactor and the fuel reactor; is the output of Fe3O4 at time t; is the output of hydrogen produced by natural gas reforming at time t; is the hydrogen production coefficient in the reaction; is the natural gas consumption at time t; is the oxygen production coefficient in the reaction; is the oxygen consumption at time t.

3. The off-grid comprehensive energy hydrogen production system planning method for hydrogen demand according to claim 1 is characterized in that: The compressor model is: Where P t comp is the power consumption of the compressor at time t; is the specific heat capacity constant of hydrogen; is the hydrogen input flow rate at time t; T in is the input hydrogen temperature; γ is the hydrogen isentropic index; η comp is the compressor working efficiency; k comp is the compression ratio; The maximum power consumption of the compressor.

4. The off-grid comprehensive energy hydrogen production system planning method for hydrogen demand according to claim 1 is characterized in that: The hydrogen storage tank model is: In the formula, is the hydrogen storage capacity of the hydrogen storage tank at time t; is the hydrogen storage capacity of the hydrogen storage tank at time t-1; is the hydrogen input flow rate at time t; is the industrial hydrogen load at time t; η in and η out efficiency of filling and releasing hydrogen storage tanks; and is the hydrogen storage capacity of the hydrogen storage tank at the first and last moment of the day; m HS_max is the maximum hydrogen storage capacity of the hydrogen storage tank.

5. The off-grid comprehensive energy hydrogen production system planning method for hydrogen demand according to claim 1 is characterized in that: The industrial hydrogen load model is: Where n H_load_min and n H_load_max are the minimum and maximum values ​​of industrial hydrogen load; and is the maximum decreasing rate and the maximum increasing rate of industrial hydrogen load; d a (τ) is a binary variable. When the industrial hydrogen load changes, d a (τ) is 1, when the industrial hydrogen load remains unchanged, d a (τ) is 0; D is the minimum interval for adjusting the industrial hydrogen load; T is the entire scheduling cycle; M is a positive number; d a (t) is the industrial hydrogen load variable, indicating whether the industrial hydrogen load changes.

6. The off-grid comprehensive energy hydrogen production system planning method for hydrogen demand according to claim 1 is characterized in that: The upper-level planning model is: The lower layer operation model is: In the formula, for construction and operating costs; is the annualized investment cost; For maintenance costs; The operating cost for the whole year; is the construction capacity of equipment i; is the construction cost of equipment i; r is the discount rate; τ i is the life cycle of device i; is the maintenance factor of equipment i; is the upper limit of the installation capacity of device i; I is the number of device types; C carbon is the carbon emission; T is the entire scheduling period; is the carbon emission factor of biomass transportation; is the biomass consumption at time t; is the carbon emission coefficient of natural gas; is the natural gas consumption at time t; is the total hydrogen production; is the output of hydrogen produced by electrolysis of water at time t; is the output of hydrogen produced by natural gas reforming at time t; is the output of hydrogen produced by biomass gasification at time t; is the unit cost of biomass; is the unit cost of natural gas.

7. The off-grid comprehensive energy hydrogen production system planning method for hydrogen demand according to claim 1 is characterized in that: The method of solving the hydrogen production system double-level programming model to obtain the optimal programming scheme includes: First, the upper-level planning model is solved using the NSGA-2 algorithm, and the lower-level operation model is solved using a commercial solver. The solution of the upper-level planning model is passed to the lower-level operation model, and the solution of the lower-level operation model is passed to the upper-level planning model. The upper and lower layers are iterated back and forth to solve the optimal planning scheme set. The weights of the three objectives of construction and operation costs, carbon emissions, and total hydrogen production are calculated based on the hierarchical analysis method, and then the TOPSIS method is used to select the optimal planning scheme.

8. An off-grid integrated energy hydrogen production system planning device for hydrogen demand, characterized in that: The device is applied to the method described in any one of claims 1 to 7, and the device comprises: A hydrogen production-storage-use full-process model construction module is used to construct a hydrogen production-storage-use full-process model of an off-grid comprehensive energy source including an off-grid hydrogen production section model, a compression buffer section model, and an industrial synthesis section model. The off-grid hydrogen production section model includes a water electrolysis hydrogen production model, a biomass gasification hydrogen production model, and a natural gas reforming hydrogen production model. The compression buffer section model includes a compressor model and a hydrogen storage tank model. The industrial synthesis section model includes an industrial hydrogen load model. A two-layer planning model construction module for a hydrogen production system is used to construct a two-layer planning model for a hydrogen production system including an upper-layer planning model and a lower-layer operation model. The upper-layer planning model aims to minimize the construction and operation costs of the hydrogen production system, minimize carbon emissions, and maximize the total hydrogen production. The lower-layer operation model aims to minimize the operation cost of the hydrogen production system. The optimal planning solution module is used to solve the double-layer planning model of the hydrogen production system to obtain the optimal planning solution.

9. An off-grid integrated energy hydrogen production system planning device for hydrogen demand, characterized in that: including memory and processor; The memory is used to store computer program code and transmit the computer program code to the processor; The processor is configured to execute the method according to any one of claims 1 to 7 according to instructions in the computer program code.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

Images