Energy efficiency evaluation method of water electrolysis hydrogen production system

Abstract

The invention relates to an energy efficiency evaluation method of a water electrolysis hydrogen production system, and belongs to the technical field of energy efficiency calculation of hydrogen production systems. The method comprises the following steps: 1) dividing core equipment and auxiliary equipment according to a system production process flow and functions of all equipment in the system; 2) constructing an energy consumption mechanism model of each device and a simplified energy consumption model of each auxiliary device; 3) combining the energy consumption mechanism model of each core device and the simplified energy consumption model of each auxiliary device to establish an energy consumption equation set; (4) solving the energy consumption equation set by taking the minimum energy consumption of the system as an optimization target, and obtaining the optimal energy consumption operation parameters of each piece of equipment; and 5) realizing energy efficiency evaluation of the system according to the optimal energy consumption operation parameters of each device, the corresponding optimal energy consumption value of the system, the actual operation parameters of each device and the corresponding actual energy consumption value. According to the method, the optimal energy consumption operation parameters of all the devices can be calculated more accurately and rapidly, and then system energy efficiency evaluation is completed accurately and rapidly.

Description

Technical Field

[0001] The invention belongs to the technical field of energy efficiency calculation of hydrogen production systems, and specifically relates to an energy efficiency evaluation method for a water electrolysis hydrogen production system. Background Art

[0002] As a clean, low-carbon, and widely used secondary energy, hydrogen energy has the characteristics of high calorific value, abundant reserves, wide sources, and various forms of utilization. It has gradually become one of the important carriers of global energy transformation and development. With the rapid development of the new energy industry, the simple water electrolysis hydrogen production technology has been accelerated. According to the different materials of the electrolyzer diaphragm, water electrolysis hydrogen production technology is mainly divided into three types: alkaline electrolysis (AWE), proton exchange membrane (PEM) electrolysis, and solid oxide (SOEC) electrolysis.

[0003] The electrolysis water hydrogen production system involves many equipments and complex process flow in industrial production. The rational formulation of operation plan is the basis for improving the quality and efficiency of the system, and the system energy efficiency evaluation is the key to the formulation of operation plan. The energy efficiency benchmark is the basic quantitative value for comparing energy efficiency levels, so it is necessary to conduct system energy efficiency evaluation, and the determination of the energy efficiency benchmark for energy efficiency evaluation is the key.

[0004] Common methods for determining energy efficiency benchmarks include mechanism modeling, mathematical analysis, and empirical methods. The mechanism modeling method constructs an energy efficiency function relationship based on the laws of thermodynamics, chemical reaction principles, physical changes, etc. The mathematical analysis method determines the energy efficiency baseline through data fitting or statistical analysis methods. The empirical method uses industry-determined standards or excellent enterprises or the optimal energy efficiency results in the production process of the enterprise as the energy efficiency benchmark. For example: the invention patent "Energy efficiency evaluation and improvement method of integrated energy system based on data drive" (CN 111724045 B) uses local energy efficiency standards as energy efficiency benchmarks. Mathematical analysis and empirical methods require a large amount of data, which is not friendly to new projects and cannot be dynamically analyzed.

[0005] In the industrial production process, each energy-consuming equipment can establish a relevant energy consumption mechanism model. The energy consumption mechanism models of each equipment in the system are combined to form an energy consumption mechanism model equation group, which can calculate the optimal energy consumption of the production process, that is, the simultaneous equation method. However, this method has high initial value requirements, is not suitable for diagnosis after calculation failure, and is difficult to form a general program. For example, the Chinese invention patent "Hierarchical Divide and Conquer Solution Method for the Overall Mathematical Model of the Thermal System" with announcement number CN109783860 B presets an initial value before the overall mathematical model of the thermal system is calculated. For this reason, the Chinese invention patent "An Optimization Method for Low-Temperature Thermal System" with announcement number CN 109636034 B adopts the simultaneous module method. The simultaneous module method replaces the mechanism model of the equipment production process with an approximate linear model, making the system model a linear equation group, which can be solved by a simpler method, but there is controversy as to whether the solution of the simplified model is consistent with the solution of the mechanism model.

[0006] Therefore, the existing method for solving the optimal energy consumption using the mechanism modeling method has the drawbacks of difficult solution or unreliable obtained results. Therefore, it is urgent to develop a method for determining the energy efficiency benchmark of the mechanism model applicable to the industrial production process to accurately and quickly determine the optimal energy consumption operation parameters, reasonably evaluate the energy utilization rate, and improve the energy efficiency of the device operation. Summary of the Invention

[0007] The purpose of the present invention is to provide an energy efficiency evaluation method for an electrolytic water hydrogen production system to solve the problem that the existing energy efficiency evaluation methods cannot take into account both evaluation efficiency and accuracy.

[0008] The present invention provides an energy efficiency evaluation method for an electrolytic water hydrogen production system to solve the above technical problems, including the following steps:

[0009] 1) According to the system production process flow and the functions of each device in the system, divide each device in the system into core devices and auxiliary devices;

[0010] 2) Construct the energy consumption mechanism models of each device and the simplified energy consumption models of the auxiliary devices;

[0011] 3) Combine the energy consumption mechanism models of each core device and the simplified energy consumption models of each auxiliary device to establish an energy consumption equation set of the system;

[0012] 4) Taking the lowest system energy consumption as the optimization goal, solve the energy consumption equation set to obtain the optimal energy consumption operation parameters of each device in the system.

[0013] 5) Realize the energy efficiency evaluation of the system according to the optimal energy consumption operation parameters of each device and the corresponding system optimal energy consumption value, as well as the actual operation parameters of each device and the corresponding actual energy consumption value.

[0014] Further, according to the optimal energy consumption operation parameters of the auxiliary devices obtained in step 4), solve the energy consumption mechanism models of each auxiliary device, and use the obtained energy consumption operation parameters of the auxiliary devices as the optimal energy consumption operation parameters of the auxiliary devices.

[0015] Further, the division method of the core devices and the auxiliary devices is as follows: Identify the key devices that realize chemical reactions, material conversion, and / or separation and purification in the production process flow as core devices; the devices that ensure the operation of the core devices are auxiliary devices.

[0016] Further, in step 2), according to the relationship between the energy consumption and the efficacy of the auxiliary devices, establish an energy consumption-efficacy mathematical model as the simplified energy consumption model of the auxiliary devices.

[0017] Further, use numerical algorithms or machine learning algorithms to solve the energy consumption equation set and the energy consumption mechanism models of the auxiliary devices.

[0018] Furthermore, the operation of each device of the system is controlled according to the optimal energy consumption operation parameters of each device.

[0019] Furthermore, in step 5), based on the optimal energy consumption operating parameters of each device and the corresponding optimal energy consumption value of the system, combined with the energy efficiency evaluation system of the water electrolysis hydrogen production system, the optimal energy efficiency index of the water electrolysis hydrogen production system is calculated; based on the actual operating parameters and actual energy consumption of each device of the water electrolysis hydrogen production system, combined with the energy efficiency evaluation system, the actual energy efficiency index of the water electrolysis hydrogen production system is calculated, and the energy efficiency evaluation of the system is realized based on the actual energy efficiency index and the optimal energy efficiency index.

[0020] Furthermore, the ratio of the actual energy efficiency index to the optimal energy efficiency index is solved as the device energy efficiency, and the energy efficiency of the water electrolysis hydrogen production system is evaluated based on the device energy efficiency.

[0021] Furthermore, the energy efficiency indicators of the energy efficiency evaluation system include economic energy efficiency indicators, and the economic energy efficiency indicators include by-products, by-product capacity benefits and output value indicators.

[0022] Furthermore, the energy efficiency indicators of the energy efficiency evaluation system include environmental energy efficiency indicators, and the environmental energy efficiency indicators include pollutant emission indicators and carbon emission reduction indicators.

[0023] The beneficial effect of the energy efficiency evaluation method of the present invention is: when optimizing the production process of a production system containing multiple sets of equipment, the commonly used methods are the simultaneous equation method and the simultaneous module method. The simultaneous equation method is to solve the energy consumption mechanism model of each device in the production system simultaneously. This method is intuitive, but it has a large amount of calculation and is not easy to converge when faced with a large-scale set of equations; and the simultaneous module method uses a simplified linear equation group to replace the mechanism equation, and there is a problem of inaccurate calculation results. The present invention is based on the production process flow, identifies the core equipment and auxiliary equipment, establishes the energy consumption mechanism model of each device and the simplified energy consumption model of each auxiliary equipment; and solves the optimal energy consumption operating parameters of each device. The optimal energy consumption operating parameter determination method of the water electrolysis hydrogen production system is used to determine the optimal energy consumption operating parameters of each device. This process does not solve the energy consumption mechanism models of all devices in the system simultaneously, but identifies the core equipment and auxiliary equipment, constructs a simplified energy consumption model of the auxiliary equipment, and replaces the energy consumption mechanism model of the auxiliary equipment with the simplified energy consumption model of the auxiliary equipment, and then solves them simultaneously. This avoids the problems of large amount of calculation and difficulty in convergence of the simultaneous equation method in the prior art and low calculation accuracy of the simultaneous module method, so that the optimal energy consumption operating parameters and optimal energy consumption of each device can be calculated more accurately and quickly, providing an accurate energy efficiency benchmark for energy efficiency evaluation, thereby improving the accuracy and efficiency of energy efficiency evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1Flow chart of the energy efficiency evaluation and online control method for the electrolytic water hydrogen production system according to the embodiment of the present invention;

[0025] Figure 2 Process flow chart of the PEM electrolytic water hydrogen production system according to the embodiment of the present invention;

[0026] Figure 3 Energy consumption flow chart of the PEM electrolytic water hydrogen production system according to the embodiment of the present invention;

[0027] Figure 4 Block diagram of the energy efficiency evaluation index system for the PEM electrolytic water hydrogen production system according to the embodiment of the present invention;

[0028] Figure 5 Calculation flow chart of the hybrid - connection module method according to the embodiment of the present invention;

[0029] Figure 6 Optimal energy consumption iterative calculation process diagram of the PEM electrolytic water hydrogen production system according to the embodiment of the present invention;

[0030] Figure 7 Schematic diagram of the online control platform for the PEM electrolytic water hydrogen production system according to the embodiment of the present invention. Specific embodiments

[0031] The following further explains the specific embodiments of the present invention in conjunction with the accompanying drawings.

[0032] In the prior art, when using the mechanism modeling method to solve the optimal energy consumption, if the simultaneous equation method is used to solve, the equations formed by the large - scale mechanism energy consumption model have a large amount of calculation and are not easy to converge, so it is difficult to solve; if the simultaneous module method is used, because a simplified linear equation system is used to replace the mechanism equation, the calculation result is unreliable. Therefore, the core of the method of the present invention lies in dividing the core equipment and auxiliary equipment, constructing an energy consumption mechanism model for each core equipment, and constructing a simplified energy consumption model for the auxiliary equipment, and then solving them simultaneously. This method combines the above two solution methods, and finally completes the solution of the optimal energy consumption operation parameters of each equipment in the system, and then is used in the energy efficiency evaluation to realize the energy efficiency evaluation of the system.

[0033] Based on the above idea, the energy efficiency evaluation method of the electrolytic water hydrogen production system in this embodiment includes the following steps:

[0034] 1) Divide each device in the system into core devices and auxiliary devices according to the system production process flow and the functions of each device in the system.

[0035] The division method of the core devices and auxiliary devices in this embodiment is: identify the key devices that realize chemical reactions, material conversion, and / or separation and purification in the production process flow as core devices; the devices that ensure the operation of the core devices are auxiliary devices.

[0036] 2) Construct the energy consumption mechanism model of each device and construct a simplified energy consumption model of each auxiliary equipment.

[0037] The energy consumption mechanism model of each device in this embodiment is established based on the laws of thermodynamics, chemical reaction principles, physical changes, etc. The simplified energy consumption model of the auxiliary equipment is an energy consumption-efficiency mathematical model established based on the relationship between the energy consumption and efficacy of the auxiliary equipment.

[0038] 3) Combine the energy consumption mechanism model of each core device and the simplified energy consumption model of each auxiliary device to establish the system's energy consumption equation group.

[0039] According to the production process of the water electrolysis hydrogen production system, the system can be divided into different process units based on the core equipment, including core equipment modules with auxiliary equipment and core equipment modules without auxiliary equipment. For the core equipment modules with auxiliary equipment, the energy consumption mechanism model of the core equipment and the simplified energy consumption model of the auxiliary equipment are combined to form a hybrid module equation group. For the core equipment modules without auxiliary equipment, the energy consumption mechanism model of the core equipment constitutes a connection module equation group. The combination of all the hybrid module equation groups and the connection module equation groups in the system constitutes the energy consumption equation group of the system. In fact, the energy consumption equation group of the system here is obtained by combining the energy consumption mechanism modules of each core equipment in the system with the simplified energy consumption models of each auxiliary equipment.

[0040] 4) Taking the minimum energy consumption of the system as the optimization goal, the energy consumption equation group is solved to obtain the optimal energy consumption operating parameters of each device in the system.

[0041] The energy consumption equation group obtained in step 3) actually includes the energy consumption mechanism model of the core equipment and the simplified energy consumption model of the auxiliary equipment. Therefore, compared with the existing method of directly combining the energy consumption mechanism models of all equipment to obtain the equation group, the equation group can be simplified, which will greatly reduce the workload of the solution process. Moreover, the core equipment still solves the optimal energy consumption operation parameters through the constructed energy consumption mechanism model, so the accuracy of the solution result to a certain extent is also guaranteed. However, since the simplified energy consumption model of the auxiliary equipment is solved in the energy consumption equation, the result obtained is not optimal compared to the equation group of the energy consumption mechanism model. Therefore, in order to ensure that the energy consumption operation parameters of the auxiliary equipment are optimal, as an implementation method, the energy consumption mechanism model of the auxiliary equipment can be constructed, and the energy consumption mechanism model of each auxiliary equipment is solved according to the energy consumption operation parameters of the auxiliary equipment obtained in step 4), and the energy consumption operation parameters of the auxiliary equipment obtained by the solution are used as the final optimal energy consumption operation parameters of the auxiliary equipment.

[0042] Therefore, this implementation method actually divides the entire solution process into two steps. The first step is to construct a set of equations by combining the energy consumption mechanism model of the core equipment and the simplified energy consumption model of the auxiliary equipment, solve the set of equations, and obtain the optimal operating parameters of the core equipment and the initial energy consumption operating parameters of the auxiliary equipment; the second step is to solve the energy consumption mechanism model of the auxiliary equipment again according to the initial energy consumption operating parameters of the auxiliary equipment solved in the first step, and obtain the optimal operating parameters of the auxiliary equipment, thereby completing the solution of the energy efficiency optimization operating parameters of the core equipment and the auxiliary equipment. In this way, the accuracy of solving the optimal operating parameters of the energy consumption of the auxiliary equipment is improved, and the accuracy of the optimal energy consumption calculation of the system is further improved, providing a more accurate energy efficiency benchmark for subsequent energy efficiency evaluation. As an optimal implementation method, numerical methods or machine learning algorithms can be used in this embodiment to solve the energy consumption equations and / or solve the energy consumption mechanism model of the auxiliary equipment. Numerical methods generally include Newton's method, Jacobi iteration method, conjugate gradient method, etc., while machine learning algorithms generally include heuristic algorithms, meta-heuristic algorithms, super-heuristic algorithms, etc.

[0043] 5) The energy efficiency evaluation of the system is realized according to the optimal energy consumption operation parameters of each device and the corresponding optimal energy consumption value of the system, as well as the actual operation parameters of each device and the corresponding actual energy consumption value.

[0044] After obtaining the optimal energy consumption operating parameters and optimal energy consumption of each device in the system, the optimal energy efficiency index is calculated based on the optimal energy consumption operating parameters and optimal energy consumption of each device, combined with the system's energy efficiency evaluation system; based on the actual operating parameters and actual energy consumption of each device, combined with the system's energy efficiency evaluation system, the system's actual energy efficiency index is obtained, and then the system energy efficiency is evaluated based on the actual energy efficiency index and the optimal energy efficiency index.

[0045] In order to improve the speed and accuracy of the optimal energy consumption operating parameters and the optimal energy consumption calculation, and thus improve the accuracy of the energy efficiency evaluation, this embodiment adopts the optimal energy consumption operating parameter determination method of the water electrolysis hydrogen production system in the above embodiment to solve the optimal energy consumption operating parameters and optimal energy consumption of each device in the system.

[0046] Furthermore, the ratio of the actual energy efficiency index to the optimal energy efficiency index is solved as the device energy efficiency, and the energy efficiency of the water electrolysis hydrogen production system is evaluated based on the device energy efficiency.

[0047] Furthermore, this embodiment takes the optimization of system energy efficiency as the goal, considers the impact of by-products, by-production capacity and environmental impact, and establishes a set of energy efficiency evaluation index system.

[0048] The energy efficiency evaluation index system contains a four-level structure. The first-level index is the overall energy efficiency index, the second-level index is the sub-item energy efficiency index, the third-level index is the sub-indicator of the second-level sub-item index, and the fourth-level index is the root index.

[0049] The overall target index is the energy efficiency of the electrolytic water hydrogen production system; the sub - performance indexes are the economic energy efficiency index, the management energy efficiency index, the production energy efficiency index, and the environmental energy efficiency index.

[0050] The economic energy efficiency index is the income per unit energy consumption and the output value per unit energy consumption; the income per unit energy consumption index includes the income of the target product per unit energy consumption, the income of by - products per unit energy consumption, and the income of by - production capacity per unit energy consumption; the output value per unit energy consumption index includes the output value of the target product per unit energy consumption, the output value of by - products per unit energy consumption, and the output value of by - production capacity per unit energy consumption.

[0051] The management energy efficiency index is the equipment failure rate, including the failure rate of equipment 1, the failure rate of equipment 2, the failure rate of equipment 3, …, the failure rate of equipment n, where n is the total number of equipment in the system.

[0052] The production energy efficiency index includes the energy consumption per unit production capacity and the energy conversion efficiency; the energy consumption per unit production capacity index is the energy consumption per unit production capacity of the target product; the energy conversion efficiency is the ratio of the theoretical energy consumption of the target product to the actual energy consumption of the equipment, including the energy conversion efficiency of equipment 1, the energy conversion efficiency of equipment 2, the energy conversion efficiency of equipment 3, …, the energy conversion efficiency of equipment n.

[0053] The environmental energy efficiency index includes the pollutant emission index and the carbon emission reduction index; the environmental energy efficiency index is the pollutant emission per unit production capacity; the carbon emission reduction index is the carbon emission reduction per unit energy consumption of the target product.

[0054] This embodiment comprehensively evaluates the system energy efficiency from four aspects of the economy, management, energy consumption, and environment of the system production operation; in the economic index, considering the income and output value of by - products and by - production capacity, it more comprehensively reflects the input - output relationship of energy and the recycling and benefit creation of by - product resources, providing basic evaluation data support for better exploring the energy utilization efficiency. This embodiment also considers the environmental energy efficiency index, fully considering the impact of the system on the environment, thus making the energy efficiency evaluation of the system more comprehensive.

[0055] Furthermore, after obtaining the optimal energy consumption operation parameters of each device in the system, the operation parameters of each device can be adjusted to the optimal parameters based on the online control platform, reducing the operation energy consumption of the device and improving the overall energy efficiency of the device.

[0056] In the current electrolytic water hydrogen production technology, the PEM electrolytic water hydrogen production technology has fast dynamic response, high hydrogen purity, high gas production pressure, and high hydrogen production efficiency, and can adapt to the volatility of renewable energy power generation. It is considered an electrolytic water hydrogen production technology with great development prospects. The PEM hydrogen production system mainly includes a water treatment unit, an electrolytic cell hydrogen production unit, a hydrogen - water separation unit, an oxygen - water separation unit, a hydrogen dehydration unit, a hydrogen purification unit, a cooling and heat exchange unit, etc., as Figure 2The following is the process flow of a PEM electrolytic water hydrogen production system. Taking the PEM electrolytic water hydrogen production system as an example, the technical solution of the present invention will be further described in detail below.

[0057] The main energy-consuming equipment of the PEM electrolytic water hydrogen production system includes a power pump, a PEM electrolytic cell, an air cooler, a chiller, a deoxidation tower, and a dehydration tower. In the process of PEM electrolytic water hydrogen production, the water treatment device, the PEM electrolytic cell, the gas-liquid separation device, the deoxidation tower, and the dehydration tower are the core equipment; the air cooler and the chiller are auxiliary equipment. According to the laws of thermodynamics, the principles of chemical reactions, physical changes, etc., an energy consumption mechanism model of each of the above equipment is established. According to the relationship between the energy consumption and the efficiency of the air cooler and the chiller, an energy consumption-efficiency mathematical model (also known as a simplified energy consumption model) of the air cooler and the chiller is established. The following are the energy consumption mechanism models of each equipment.

[0058] ① Energy consumption mechanism model of the power pump.

[0059] y 泵 = w·t

[0060] Where y 泵 is the energy consumption of the power pump, in kW·h; w is the power of the feed water pump motor, in kW; t is the operating duration, in h.

[0061] ② Energy consumption mechanism model of the electrolytic cell.

[0062] y 电解槽 = i·u·t

[0063] Where y 电解槽 is the energy consumption of the electrolytic cell, in kW·h; i is the operating current of the electrolytic cell, in A; u is the operating voltage of the electrolytic cell, in V.

[0064] ③ Energy consumption mechanism model of the air cooler.

[0065] y 空冷器 = w 风扇电机 ·t + w 循环水泵 ·t

[0066] In the formula, y 空冷器 is the energy consumption of the air cooler, in kW·h; w 风扇电机 is the power of the air cooler fan motor, in W; w 循环水泵 is the power of the circulating water pump, in W.

[0067] ④ Energy consumption mechanism model of the chiller.

[0068] y 冷冻机 = w 风扇电机 ·t + w 压缩机 ·t

[0069] In the formula, y冷冻机 is the energy consumption of the chiller, in kW·h; w 风扇电机 is the power of the chiller fan motor, in W; w 压缩机 is the power of the expansion compressor, in W.

[0070] ⑤ Deoxygenation tower energy consumption mechanism model.

[0071] y 脱氧塔 = w 加热器 ·t

[0072] In the formula, y 脱氧塔 is the energy consumption of the deoxygenation tower, in kW·h; w 加热器 is the power of the deoxygenation tower heater, in W.

[0073] ⑥ Dewatering tower energy consumption mechanism model.

[0074] y 脱水塔 = w 再生 ·t

[0075] In the formula, y 脱水塔 is the energy consumption of the dewatering tower, in kW·h; w 再生 is the regeneration heating power of the dewatering tower, in W.

[0076] The following are the simplified energy consumption models of each auxiliary equipment:

[0077] ⑦ Air cooler energy consumption - efficiency model.

[0078] g ac = c ac ·h ac

[0079] In the formula, g ac is the energy consumption of the air cooler, in kW·h; c ac is the energy efficiency coefficient of the air cooler; h ac is the heat transfer quantity of the air cooler, in kW·h.

[0080] ⑧ Chiller energy consumption - efficiency model.

[0081] g rc = c rc ·h rc

[0082] In the formula, g rc is the energy consumption of the chiller, in kW·h; c rc is the energy efficiency coefficient of the chiller; h rc is the heat transfer quantity of the chiller, in kW·h.

[0083] Such as Figure 5As shown in the figure, the energy consumption mechanism model of the water treatment device, PEM electrolyzer, gas-liquid separation device, deoxygenation tower, and dehydration tower in the hydrogen production system is combined with the simplified energy consumption model of the air cooler and refrigerator to obtain the energy consumption equation group of the hydrogen production system. The energy consumption equation group is solved by the optimization algorithm to obtain the optimal energy consumption operating parameters of the water treatment device, PEM electrolyzer, gas-liquid separation device, deoxygenation tower, and dehydration tower, as shown in Figure 6 The figure shows the iterative calculation process of the optimal energy consumption of the PEM water electrolysis hydrogen production system. The energy consumption mechanism model of the air cooler and refrigerator is solved according to the results obtained by solving the energy consumption equation group to obtain the optimal energy consumption operating parameters of the air cooler and refrigerator. According to the equipment operating parameters at the optimal energy consumption of each device, based on the online control platform, the operating parameters of each device are adjusted to the optimal parameters, the equipment operating energy consumption is reduced, and the overall energy efficiency of the device is improved.

[0084] According to the factors affecting the energy efficiency of the PEM water electrolysis hydrogen production system, an energy efficiency evaluation index system of the PEM water electrolysis hydrogen production system was established, an energy consumption mechanism model of the equipment contained in the hydrogen production system was established, and the optimal energy consumption operating parameter determination method of the industrial production system of the above embodiment was used to determine the operating parameters of the system at the optimal energy consumption. Figure 1 As shown, it specifically includes the following contents:

[0085] 1. Obtain basic information about the PEM water electrolysis hydrogen production system, including the process flow, operating rated parameters, and system environment data of the PEM water electrolysis hydrogen production system.

[0086] 2. According to the process flow of the PEM water electrolysis hydrogen production system, the evaluation objects mainly include soft water treatment tanks, reverse osmosis membrane tanks, ion exchange resin tanks, etc. involved in water treatment; PEM electrolyzers, liquid heat exchangers, gas heat exchangers, oxygen-water separators, hydrogen-water separators for water electrolysis hydrogen production; deoxygenation towers and dehydration towers used for hydrogen purification, such as Figure 3 Shown is the energy consumption flow chart of the PEM water electrolysis hydrogen production system.

[0087] 3. With the goal of optimizing the energy efficiency of the PEM water electrolysis hydrogen production system, establish an energy efficiency evaluation index system, such as Figure 4As shown in the figure; the energy efficiency evaluation system includes a four-level structure; the first-level indicator is the overall target indicator; the second-level indicator is the sub-performance indicator; the third-level indicator is the sub-indicator of the sub-performance indicator; the fourth-level indicator is the root indicator. The overall target indicator is the energy efficiency of the PEM electrolytic water hydrogen production system; the sub-performance indicators are the economic energy efficiency indicator, the management energy efficiency indicator, the production energy efficiency indicator, and the environmental energy efficiency indicator. The economic energy efficiency indicator is the unit energy consumption revenue indicator and the unit energy consumption output value; the sub-indicators of the unit energy consumption revenue indicator include the unit energy consumption target product revenue, the unit energy consumption by-product revenue, and the unit energy consumption by-product energy revenue; the sub-indicators of the unit energy consumption output value include the unit energy consumption target product output value, the unit energy consumption by-product output value, and the unit energy consumption by-product energy output value. The management energy efficiency indicator includes the failure rate of equipment 1, the failure rate of equipment 2, the failure rate of equipment 3,..., the failure rate of equipment n. The production energy efficiency indicator includes the unit production energy consumption and the energy conversion efficiency; the unit production energy consumption is the unit production energy consumption of the target product; the energy conversion efficiency indicator includes the energy conversion efficiency of equipment 1, the energy conversion efficiency of equipment 2, the energy conversion efficiency of equipment 3,..., the energy conversion efficiency of equipment n. The environmental energy efficiency indicator includes the pollutant emission indicator and the carbon emission reduction indicator; the pollutant emission indicator is the unit production pollutant emission; the carbon emission reduction indicator is the unit energy consumption carbon emission reduction of the target product.

[0088] The specific calculation methods of the economic energy efficiency indicator, the management energy efficiency indicator, the production energy efficiency indicator, and the environmental energy efficiency indicator of the electrolytic water hydrogen production system are further described below.

[0089] (1) The unit energy consumption revenue is the sum of the unit energy consumption target product revenue, the unit energy consumption by-product revenue, and the unit energy consumption by-product energy revenue. The unit energy consumption target product revenue is the ratio of the sales revenue of the target product of the PEM electrolytic water hydrogen production system to the energy consumption in a certain statistical period. The unit energy consumption by-product revenue is the ratio of the by-product revenue of the PEM electrolytic water hydrogen production system to the energy consumption in a certain statistical period. The unit energy consumption by-product energy revenue is the ratio of the by-product energy revenue of the PEM electrolytic water hydrogen production system to the energy consumption in a certain statistical period.

[0090] ① The unit energy consumption target product revenue is calculated by the following formula:

[0091] e H =F H / E

[0092] In the formula, e H is the unit energy consumption target product (the target product of PEM hydrogen production is hydrogen) revenue, with the unit of yuan / kgce; F H is the target product revenue in a certain statistical period, with the unit of yuan; E is the system energy consumption in a certain statistical period, with the unit of kgce. e iThe standard coal equivalent of the energy consumed by the device can be calculated according to the General Principles for Calculation of Comprehensive Energy Consumption (GBT 2589-2020), and m is the number of types of energy consumed. The energy consumed in PEM hydrogen production is electricity and water.

[0093] ② The by-product income per unit energy consumption is calculated by the following formula:

[0094] e O =F O / E

[0095] In the formula, e O is the by-product income per unit energy consumption (the by-product of PEM hydrogen production is oxygen), and the unit is yuan / kgce; F O is the by-product income during a certain statistical period, and the unit is yuan.

[0096] ③ The by-product production income per unit energy consumption is calculated by the following formula:

[0097] e t =F t / E

[0098] In the formula, e t is the by-product production income per unit energy consumption (the by-product production of PEM hydrogen production is waste heat), and the unit is yuan / kgce; F t is the by-product production income during a certain statistical period, and the unit is yuan.

[0099] (2) The output value per unit energy consumption is the sum of the output value of the target product per unit energy consumption, the output value of the by-product per unit energy consumption, and the output value of the by-product production per unit energy consumption. The output value of the target product per unit energy consumption is the ratio of the output value of the target product of the PEM electrolytic water hydrogen production system to the energy consumption during a certain statistical period. The output value of the by-product per unit energy consumption is the ratio of the output value of the by-product of the PEM electrolytic water hydrogen production device to the energy consumption. The output value of the by-product production per unit energy consumption is the ratio of the output value of the by-product production of the PEM electrolytic water hydrogen production system to the energy consumption.

[0100] ① The output value of the target product per unit energy consumption is calculated by the following formula:

[0101] s H =V H / E

[0102] In the formula, s H is the output value of the target product per unit energy consumption, and the unit is yuan / kgce; V H is the output value of the target product during a certain statistical period, and the unit is yuan. V H =C p ·C H2C ·P H , C p is the price of standard coal, and the unit is yuan / kg; C H2Cis the coefficient for converting hydrogen into standard coal, with the unit of 0.3329 kgce / Nm 3 ; P H is the hydrogen volume, with the unit of Nm 3 .

[0103] ② The by-product output value per unit energy consumption is calculated by the following formula:

[0104] s O = V O / E

[0105] In the formula, s O is the by-product output value per unit energy consumption, with the unit of yuan / kgce; V O is the by-product output value during a certain statistical period, with the unit of yuan. V O = C p ·C O2C ·P O , C O2C is the coefficient for converting oxygen into standard coal, with the unit of 0.400 kgce / Nm 3 ; P O is the oxygen volume, with the unit of Nm 3 .

[0106] ③ The by-product output value per unit energy consumption is calculated by the following formula:

[0107] s t = V t / E

[0108] In the formula, s t is the by-product output value per unit energy production capacity, with the unit of yuan / kgce; V t is the by-product output value during a certain statistical period, with the unit of yuan. V t = C p ·C t2C ·P t , C t2C is the coefficient for converting waste heat into standard coal, with the unit of 0.0341 kgce / MJ; P t is the waste heat volume, with the unit of MJ.

[0109] (3) The management energy efficiency indicators are mainly the equipment downtime rate, including the equipment 1 downtime rate, equipment 2 downtime rate, equipment 3 downtime rate, etc., which are determined according to the production statistical data;

[0110] The equipment failure rate is calculated by the following formula:

[0111] η d = t f / t r × 100%

[0112] In the formula, η dis the equipment failure rate, %; t f is the equipment downtime duration within a certain statistical period, with the unit of h; t r is the equipment operation duration within a certain statistical period, with the unit of h.

[0113] (4) Production energy efficiency indicators include unit production energy consumption and energy conversion efficiency. The unit production energy consumption is the unit production energy consumption of the target product, that is, the unit production energy consumption of the target product is the ratio of the energy consumption E of the system within a certain statistical period to the production capacity of the target product. The hydrogen production efficiency of the electrolyzer is the ratio of the theoretical power consumption for hydrogen production to the actual power consumption of the equipment.

[0114] ① The unit production energy consumption is calculated by the following formula:

[0115] y H = E / P H

[0116] In the formula, y H is the energy consumption per unit quantity of the target product, with the unit of kgce / Nm 3 ; E is the energy consumption of the system within a certain statistical period, with the unit of kgce; P H is the hydrogen production, with the unit of Nm 3 .

[0117] ② The hydrogen production efficiency of the electrolyzer is calculated by the following formula:

[0118] η c = E ct / E ca × 100%

[0119] In the formula, η c is the hydrogen production efficiency of the electrolyzer, %; E ct is the theoretical power consumption per unit production of hydrogen production by electrolyzing water, with the unit of kgce / Nm 3 ; E ca is the actual power consumption per unit production of hydrogen production by electrolyzing water, with the unit of kgce / Nm 3 .

[0120] (5) Environmental energy efficiency indicators include pollutant emission indicators and carbon emission reduction indicators. The pollutant emission indicator is the pollutant emission per unit production; the pollutant emission per unit production is the ratio of the pollutant emission within a certain statistical period to the production capacity of the target product; the carbon emission reduction indicator is the carbon emission reduction per unit production, which is the ratio of the carbon emission reduction within a certain statistical period to the production of the target product.

[0121] ① The pollutant emission per unit production of hydrogen is calculated by the following formula:

[0122] s wo = S wo / P H

[0123] where s wo is the pollutant emission per unit output of hydrogen, with the unit of kg / Nm 3 ; S wo is the pollutant emission during hydrogen production by electrolyzing water, with the unit of kg.

[0124] ② The carbon emission reduction per unit energy consumption of hydrogen is calculated by the following formula:

[0125]

[0126] where CER s is the carbon emission reduction per unit output of PEM electrolytic hydrogen production, with the unit of kg / Nm 3 ; C gr is the carbon emission per unit output of hydrogen production by electrolyzing water, with the unit of kg / Nm 3 ; C ga is the carbon emission per unit output of gray hydrogen production, with the unit of kg / Nm 3 , about 10.0 - 16.0 kg CO 2 e / kg.

[0127] According to the actual operation data of the hydrogen production system and combined with the above energy efficiency evaluation system, calculate the actual energy efficiency index of the hydrogen production system; use the Newton iteration method to solve the optimal operation parameters of the core equipment and auxiliary equipment of the hydrogen production system, obtain the optimal energy consumption value, and calculate the optimal energy efficiency index based on the above index calculation method. The calculation results are shown in Table 1.

[0128] Table 1 Energy Efficiency Index of PEM Electrolytic Hydrogen Production Device

[0129]

[0130] When calculating the total evaluation index, assign weights to each level of index by combining the expert scoring method. Then calculate the total evaluation index according to the assigned weight values and the calculation results of each level of index. As an implementation method, the weights of the first-level index and the second-level index can be set as equal weights.

[0131] Compare the calculated actual energy efficiency index with the energy efficiency index under the optimal working condition, and the system energy efficiency can be calculated to be 92.1%.

[0132] The energy efficiency evaluation method of the present invention evaluates the comprehensive energy efficiency of target products, by-products, and by-product energy from four aspects: economic energy efficiency, management energy efficiency, energy consumption efficiency, and environmental energy efficiency, which better reflects the relationship between energy input and output; when calculating the optimal operation parameters of system energy consumption, the hybrid-simultaneous module method is proposed, which avoids the problems of large calculation and difficult convergence of the simultaneous equation method and the low accuracy of the simultaneous module method, and can calculate the optimal energy consumption operation parameters of equipment faster and more accurately, providing technical support for the energy-saving and consumption-reducing optimal operation of the system and equipment.

[0133] The present invention also provides an online optimization platform for PEM electrolytic water hydrogen production, as Figure 7 shown; the platform includes an environment, sensors for working condition parameters, a processor, a memory, an actuator and a communication bus; data is transmitted between the sensors, the processor, the memory and the actuator by using the communication bus;

[0134] The sensors are relevant sensors such as temperature sensors, pressure sensors, gas / liquid flow sensors, liquid level sensors, current sensors, voltage sensors, etc.

[0135] The processor is an MCU microprocessor or a processor such as an FPGA or a CPLD programmable chip.

[0136] The memory is various types of memories such as RAM, ROM, USB flash drives, etc. that store data based on electrical energy; hard disks, floppy disks, magnetic tapes, etc. that store data based on magnetic energy; CDs, DVDs, etc. that store information based on light energy.

[0137] The actuator is a process controller and an electrical controller. The process controller is mainly an actuator based on pneumatic or electric power, and the electrical controller is mainly a logic circuit actuator based on relays, contactors, etc.

[0138] The control process is that the sensors transmit the collected data to the processor, the processor calls the control instructions in the memory, calculates the optimal operating parameters of the system under the current operating conditions, analyzes the difference between the device operating parameters and the optimal operating parameters, and adjusts the device operating parameters through the actuator.

Claims

1. An energy efficiency evaluation method for an electrolytic water hydrogen production system, characterized in that, the method comprises the following steps: 1) Divide each device in the system into a core device and an auxiliary device according to the system production process flow and the functions of each device in the system; 2) Construct an energy consumption mechanism model for each device and a simplified energy consumption model for the auxiliary device; 3) Combine the energy consumption mechanism models of each core device and the simplified energy consumption models of each auxiliary device to establish an energy consumption equation set for the system; 4) With the lowest system energy consumption as the optimization goal, solve the energy consumption equation set to obtain the optimal energy consumption operation parameters of each device in the system; 5) Realize the energy efficiency evaluation of the system according to the optimal energy consumption operation parameters of each device and the corresponding optimal system energy consumption value, as well as the actual operation parameters of each device and the corresponding actual energy consumption value.

2. The energy efficiency evaluation method for an electrolytic water hydrogen production system according to claim 1, characterized in that, According to the optimal energy consumption operation parameters of the auxiliary device obtained in step 4), solve the energy consumption mechanism model of each auxiliary device, and use the obtained energy consumption operation parameters of the auxiliary device as the optimal energy consumption operation parameters of the auxiliary device.

3. The energy efficiency evaluation method for an electrolytic water hydrogen production system according to claim 1 or 2, characterized in that, The division method of the core device and the auxiliary device is: identify the key devices that realize chemical reactions, material conversion and / or separation and purification in the production process flow as core devices; the devices that ensure the operation of the core devices are auxiliary devices.

4. The energy efficiency evaluation method for an electrolytic water hydrogen production system according to claim 1 or 2, characterized in that, In step 2), establish an energy consumption-power mathematical model as the simplified energy consumption model of the auxiliary device according to the relationship between the energy consumption and power of the auxiliary device.

5. The energy efficiency evaluation method for an electrolytic water hydrogen production system according to claim 1 or 2, characterized in that, Use a numerical algorithm or a machine learning algorithm to solve the energy consumption equation set and the energy consumption mechanism model of the auxiliary device.

6. The energy efficiency evaluation method for an electrolytic water hydrogen production system according to claim 1 or 2, characterized in that, Control the operation of each device in the system according to the optimal energy consumption operation parameters of each device.

7. The energy efficiency evaluation method for an electrolytic water hydrogen production system according to claim 1 or 2, characterized in that, In step 5), according to the optimal energy consumption operation parameters of each device and the corresponding optimal system energy consumption value, combined with the energy efficiency evaluation system of the electrolytic water hydrogen production system, calculate the optimal energy efficiency index of the electrolytic water hydrogen production system; according to the actual operation parameters and actual energy consumption of each device of the electrolytic water hydrogen production system, combined with the energy efficiency evaluation system, calculate the actual energy efficiency index of the electrolytic water hydrogen production system, and realize the energy efficiency evaluation of the system according to the actual energy efficiency index and the optimal energy efficiency index.

8. The energy efficiency evaluation method for an electrolytic water hydrogen production system according to claim 7, characterized in that, Solve the ratio of the actual energy efficiency index and the optimal energy efficiency index as the device energy efficiency, and evaluate the energy efficiency of the electrolytic water hydrogen production system with the device energy efficiency.

9. The energy efficiency evaluation method for an electrolytic water hydrogen production system according to claim 7, characterized in that, The energy efficiency indicators of the energy efficiency evaluation system include economic energy efficiency indicators, and the economic energy efficiency indicators include by-products, by-product energy production benefits, and output value indicators.

10. The energy efficiency evaluation method of the electrolytic water hydrogen production system according to claim 7, characterized in that, the energy efficiency indicators of the energy efficiency evaluation system include environmental energy efficiency indicators, and the environmental energy efficiency indicators include pollutant emission indicators and carbon emission reduction indicators.

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