Clean energy electrolysis hydrogen production system

Abstract

A clean energy electrolysis hydrogen production system comprises a power supply system and an electrolysis system, the power supply system comprises a nuclear energy power generation device and a new energy power supply device comprising one or more sets of photovoltaic power generation devices and / or wind power generation devices, and the power supply power of the nuclear energy power generation device to the electrolysis system is not lower than 30% of the rated power of the electrolysis system. The power supply system supplies power to the electrolysis system through the power transmission system, is connected with the nuclear energy power generation device and the new energy power generation device through a plurality of independent alternating current buses, converts alternating current into direct current through the rectifying device, and outputs the direct current to the electrolysis device through a direct current bus. The system can perform electrolytic hydrogen production by using clean energy, consumes fluctuation of wind power and photovoltaic power generation, and improves the stability and safety of electrolytic hydrogen production at the same time.

Description

Technical Field

[0001] The utility model belongs to the field of electrolytic hydrogen production, and specifically relates to a clean energy electrolytic hydrogen production system. Background Art

[0002] As the climate challenges brought by global warming become increasingly severe, the need to replace traditional fossil energy with clean energy is becoming more urgent. At present, mainstream renewable energy sources such as wind power and photovoltaics are generally intermittent, random, and volatile. When connected to the power system, they are easy to challenge the safety and stability of the power grid operation. At the same time, the power grid has limited peak-shaving capacity and insufficient transmission capacity, making it difficult to effectively absorb wind power and photovoltaics. Therefore, using wind power and photovoltaics for electrolytic hydrogen production is considered to be an effective technical route to improve the utilization efficiency of wind power and photovoltaics. However, relying solely on wind power and photovoltaics to produce hydrogen still has the problem of power fluctuations. Especially when the rated power of the electrolytic cell is relatively low, the concentration of hydrogen produced by hydrogen production may fall within the explosion limit and cause danger. If traditional energy is used to provide a stable basic power supply, carbon emissions will still be generated, which is contrary to the purpose of clean energy hydrogen production. In contrast, nuclear power has a stable power supply and does not produce carbon emissions during operation, which is very suitable for maintaining the power stability of electrolytic hydrogen production. Therefore, providing a clean energy electrolytic hydrogen production system that cooperates with nuclear power and new energy has positive significance for improving the efficiency and safety of electrolytic hydrogen production. Utility Model Content

[0003] The purpose of the utility model is to provide a clean energy electrolytic hydrogen production system to improve the efficiency and safety of electrolytic hydrogen production.

[0004] According to an embodiment of the utility model, a clean energy electrolysis hydrogen production system is provided, which includes a power supply system and an electrolysis system. The power supply system includes a nuclear power generation device and a new energy power supply device, and the new energy power supply device includes one or more photovoltaic power generation devices and / or wind power generation devices. The power supply power of the nuclear power generation device to the electrolysis system is not less than 30% of the rated power of the electrolysis system. The electrolysis system includes a water supply device, a mixing device, an electrolytic cell and an oxygen separation device. The water supply device supplies water to the mixing device. The mixing device, the electrolytic cell and the oxygen separation device are connected in a closed loop and contain a circulating electrolyte. The mixing device is used to mix the electrolyte with the water input by the water supply device. The electrolytic cell is used for electrolysis hydrogen production, and the oxygen separation device is used to separate the oxygen produced by electrolysis. The power supply system is connected to the electrolysis system through a power transmission system to allow the power supply system to supply power to the electrolysis system; wherein the power transmission system includes a plurality of independent AC bus bars, a rectifier and a DC bus bar, the plurality of independent AC bus bars are connected to the rectifier device to allow the rectifier device to convert AC power into DC power, the rectifier device is connected to the DC bus bar, and the DC bus bar is connected to the electrolysis system; the nuclear power generation device and each set of the wind power generation device are respectively connected to the independent AC bus bars, and the photovoltaic power generation device is connected to the independent AC bus bar through an inverter, and the inverter is used to convert the DC power generated by the photovoltaic power generation device into AC power.

[0005] The system combines nuclear power with renewable energy power generation, using the stable nuclear power system to smooth out the volatility of renewable energy power generation, thereby improving the stability of hydrogen production by electrolysis; nuclear power is used to ensure the rated power ratio of the electrolysis device, preventing the concentration of hydrogen produced by electrolysis from falling within the explosion limit range, thereby improving the safety of hydrogen production by electrolysis.

[0006] Furthermore, in some embodiments, the independent AC busbars are set in parallel. The parallel design makes the system more expandable. When additional wind power generation or photovoltaic power generation devices need to be added, new parallel lines can be added to the original independent AC busbars. A single line failure will not affect the overall power supply, and the system is easy to maintain.

[0007] Furthermore, in some embodiments, the new energy power supply device also includes an energy storage battery.

[0008] Furthermore, in some embodiments, the energy storage battery includes an active zero control system and a state of charge SOC recovery control system. Active zero control can prevent the energy storage battery from receiving active power in a steady state, ensuring that all the electricity generated by photovoltaic power generation and / or wind power generation is used by the electrolysis system load. The state of charge SOC recovery control system is used to keep the energy storage battery within a reasonable charge and discharge range to extend the battery life.

[0009] Furthermore, in some embodiments, when the wind power generation device exists in the clean energy electrolysis hydrogen production system, the wind power generation device is configured as a doubly-fed induction generator.

[0010] Furthermore, in some embodiments, in the doubly-fed induction generator, in the dq rotating coordinate system, the rotor-side converter adopts dual closed-loop control of active power outer loop and current inner loop for the q-axis, and adopts zero reference current single-loop control for the d-axis.

[0011] Furthermore, in some embodiments, in the dq rotating coordinate system, the grid-connected side converter d-axis double closed-loop control adopts a DC bus voltage outer loop and a current inner loop; the q-axis adopts a reactive outer loop and a current inner loop control.

[0012] Furthermore, in some embodiments, the electrolytic cell is configured as a monopolar alkaline water electrolysis hydrogen production cell stack or a bipolar alkaline water electrolysis hydrogen production cell stack.

[0013] Furthermore, in some embodiments, the water supply device also includes a water treatment device, and the water treatment device is used to treat the water input into the mixing device into pure water.

[0014] Furthermore, in some embodiments, the electrolysis system further includes a dehumidifier and a drying heat exchanger, and the dehumidifier and the drying heat exchanger are connected to the electrolysis cell for drying and cooling the produced hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of a clean energy electrolysis hydrogen production device in one embodiment;

[0016] Figure 2 It is a schematic structural diagram of a clean energy electrolysis hydrogen production device in another embodiment;

[0017] Figure 3 This is a schematic structural diagram of a clean energy electrolysis hydrogen production device in another embodiment;

[0018] Figure 4 This is a schematic diagram of the structure of a power regulation control system in one embodiment;

[0019] Figure 5 This is a schematic structural diagram of a wind power generation device in one embodiment;

[0020] Figure 6 This is a schematic diagram of the structure of a photovoltaic power generation device in one embodiment;

[0021] Figure 7 This is a schematic diagram of the charge and discharge control structure of an energy storage battery in one embodiment;

[0022] Figure 8 This is a schematic diagram of the structure of an electrolysis system in one embodiment;

[0023] Fig. 9 This is a schematic diagram of the structure of a monopolar alkaline water electrolysis hydrogen production cell stack in one embodiment;

[0024] Fig.10 Schematic diagram of the structure of a bipolar alkaline water electrolysis hydrogen production cell stack in one embodiment.

[0025] The purpose of the above drawings is to provide a detailed description of the present invention so that those skilled in the art can understand the technical concept of the present invention, but it is not intended to limit the present invention. For the sake of simplicity, the above drawings only schematically depict structures related to the technical features of the present invention, and do not strictly depict the complete structure and all details in accordance with the actual proportion. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0027] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The phrase appearing in various locations in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive independent or alternative embodiments. Those skilled in the art should be able to understand that the embodiments herein may be combined with other embodiments without causing structural conflicts.

[0028] In the description of this article, unless otherwise clearly specified and limited, the technical terms "installed", "connected", "connected" and the like should be understood in a broad sense, which can be a movable connection, a fixed connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0029] In the description of this document, terms indicating orientation or positional relationships, such as "up", "down", "left", "right", "horizontal", "vertical", "height", "length", and "width", are intended to accurately describe the embodiments and simplify the description, but are not intended to limit the parts or structures involved to have a specific orientation, be installed or operate in a specific orientation, and should not be construed as a limitation on the embodiments in this document.

[0030] In the description of this article, the terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating relative importance or limiting the quantity, specific order or primary and secondary relationship of the described technical features. In the description of this article, the meaning of "plurality" is at least two.

[0031] At present, fossil fuels such as coal, oil, and natural gas still account for about 85% of the energy supply, but the air pollution and greenhouse effect caused by the combustion of fossil fuels have brought increasingly severe challenges to economic and social development. At the same time, in the process of thermoelectric conversion, the conversion rate is less than 40% due to the efficiency limitation of the Rankine cycle, which is a serious waste. Among non-fossil energy sources, hydrogen energy, as a clean, efficient and carbon-free energy, has received widespread attention. However, as a secondary energy source, hydrogen energy needs to be produced from primary energy. If fossil energy is used to generate electricity and produce hydrogen, it is essentially contrary to the purpose of developing hydrogen energy. Renewable energy represented by wind power and photovoltaic power, due to its inherent intermittent, random, volatile and low reliability characteristics, direct access to the power grid in large quantities will make it difficult for the power grid to peak, resulting in operational safety risks. Wind power and photovoltaic power will also lead to difficulties in consumption and waste of abandoned electricity. Therefore, converting wind power and photovoltaic power, which are difficult to store, into hydrogen energy, which is relatively easy to store and transport, is an effective way to improve the utilization efficiency of renewable energy. However, considering the volatility of wind power and photovoltaic power, when the rated power of the electrolytic hydrogen production device is relatively low, it is still not conducive to the continuous and stable production of electrolytic hydrogen production. Nuclear energy, as a clean and stable form of energy, combines nuclear power with wind power and photovoltaics, and can maintain stable and continuous production of hydrogen by electrolysis in windless and sunless weather.

[0032] An embodiment of the utility model provides a clean energy electrolysis hydrogen production system, which utilizes a nuclear power generation device combined with a new energy power supply device including a wind power generation device and / or a photovoltaic power generation device to electrolyze water to produce hydrogen, thereby improving the utilization efficiency of wind power and photovoltaic power while providing a stable supply of hydrogen energy.

[0033] In one embodiment, the system structure is as follows Figure 3As shown, it includes a power supply system and an electrolysis system, wherein the power supply system includes a nuclear power generation device 1, and the power supply power provided by the nuclear power generation device 1 to the electrolysis system is not less than 30% of the rated power of the electrolysis system; the power supply system also includes a new energy power supply device, and the new energy power supply device includes one or more photovoltaic power generation devices 9 and / or wind power generation devices 8. The electric energy generated by the power supply system is transported to the electrolysis system 5 through the power regulation and control device 4 to electrolyze water to produce hydrogen. After the produced hydrogen is stored in the storage device 6, it is transported to the downstream of the application chain as energy or chemical raw materials by the transportation system 7 through pipeline transportation or mobile storage tank transportation. Among them, the power supply system and the electrolysis system are connected through the power transmission system, and the power transmission system includes multiple independent AC busbars. The nuclear power generation device 1, each set of photovoltaic power generation devices 9 and each set of wind power generation devices 8 are connected and powered by an independent AC busbar respectively. Among them, the photovoltaic power generation device 9 is first connected to the inverter to convert the direct current generated by the photovoltaic power generation device 9 into alternating current, and then transmitted to the independent AC busbar. After the independent AC bus is connected to the power regulation and control device 4, the AC power is converted into DC power by the rectifier, and the electric energy is transmitted to the electrolysis system by the medium voltage DC bus. The independent AC busbars are connected in parallel. When expansion is required, a newly connected independent AC busbar can be directly added to increase the wind power generation device 8 or photovoltaic power generation device 9. In different embodiments, according to the environmental conditions of the construction location of the clean energy electrolysis hydrogen production system, the new energy power supply device can adopt different configurations: it can be as follows: Figure 1 The figure only includes a wind power generation device 8, and it can also be as shown in FIG. Figure 2 The photovoltaic power generation device 9 is shown as an example. Figure 3 The diagram shows both a wind power generation device 8 and a photovoltaic power generation device 9 .

[0034] In such Figure 3 In the clean energy electrolysis hydrogen production system shown in FIG. 1 , the structure of the power regulation and control device 4 is as follows: Figure 4 As shown. The wind power generation device 8 adopts a doubly fed induction motor (DFIG), and the photovoltaic power generation device adopts a photovoltaic array. In addition, batteries 8' and batteries 9' are provided. In addition to being able to store the electric energy output by the wind power generation device 8 and the photovoltaic power generation device 9 that exceeds the hydrogen production demand, they can also provide voltage and frequency support for the wind power generation device 8 and the photovoltaic power generation device 9 respectively, and support the black start process of the wind power generation device 8 and the photovoltaic power generation device 9. The AC power on each independent AC bus is converted and transmitted to the medium voltage DC bus by an AC-to-DC rectifier device as a power source for electrolyzing water to produce hydrogen. The power regulation and control device 4 can manage the power output and minimize the use of battery 8' and battery 9' for energy storage to extend their life.

[0035] In a preferred embodiment, the structure of the wind power generation device 8 is as follows: Figure 5As shown, based on double-fed induction control, when the wind speed exceeds the rated wind speed, the wind power generation device can maintain the output power at the rated power; when the wind speed is greater than the tripping speed, the device stops running to protect the components. In the dq rotating coordinate system, the wind turbine rotor side converter RSC adopts dual closed-loop control of the active power outer loop and the current inner loop for the q axis to ensure current tracking. In order to achieve rapid response to the converter, the d axis adopts single-loop control with zero reference current. Wind turbine grid-connected side converter GSC control requirements U dc The d-axis double closed-loop control uses the DC bus voltage outer loop and current inner loop, and the q-axis uses the reactive outer loop and current inner loop control. convref = 0. The system does not output reactive power, reducing the capacity configuration of the converter. The mechanical power of the wind turbine blade of the doubly fed induction generator can be calculated by the following method: P wind =0.5ρAv 3 C p (λ,θ), where ρ is the air density, A is the area swept by the fan rotor blades, v is the wind speed, and C p is the power coefficient (rotor efficiency), which is a function of the tip speed ratio λ and the pitch angle θ.

[0036] In a preferred embodiment, the structure of the photovoltaic power generation device 9 is as follows: Figure 6 As shown, it includes photovoltaic panels, maximum power tracking boost converters, inverters and their filter circuits and transformers. The photovoltaic converter is controlled in maximum power tracking mode. The photovoltaic power generation power can be determined by the short-circuit current, open-circuit voltage, maximum operating current and voltage of the photovoltaic array: P v =(Y v (R T / R STC )(1+η(T c -T STG )))(1-γ). Among them, P v is the actual power of the photovoltaic unit, Y v is the rated power of the photovoltaic unit, R T is the actual intensity of solar radiation, R STG is the light intensity under standard test conditions, η is the temperature coefficient of the photovoltaic module, T c is the actual temperature of the PV module, T STG is the temperature under standard test conditions (25°C), and γ is the shading coefficient of the photovoltaic array.

[0037] In a preferred embodiment, the battery charge and discharge control structure is as follows Figure 7As shown, an energy storage battery is set on the basis of the voltage and current dual closed-loop control of the grid-connected inverter. The outer loop of the battery has two functions: active zero control and state of charge SOC recovery control. Through the AC bus voltage floating, the q-axis voltage reference value of the voltage outer loop floats between 0.9-1.1. The function of active zero control is to prevent the energy storage battery from receiving active power in a steady state, and all the electricity from renewable energy wind power or photovoltaic power generation is used by the load of the water electrolysis hydrogen production facility. When it is detected that the energy storage battery outputs active power, the AC bus voltage increases. The function of the state of charge SOC recovery is to keep the energy storage state of charge SOC within a reasonable charging and discharging range. When the state of charge SOC is lower than the set value of 0.8, the AC bus voltage decreases. The charging capacity Q of the battery c It can be expressed as Among them I c is the charging current, t c is the charging time. Discharge capacity Q d It can be expressed as: Among them I d is the discharge current, t d is the discharge time. The state of charge SOC can be expressed as SOC = Q(t) / Q b , where Q(t) is the actual capacity of the battery, Q b is the rated capacity of the battery.

[0038] In a preferred embodiment, the electrolysis system structure is as follows Figure 8 As shown, it includes a water supply device 10, a mixing device 11, an electrolytic cell 12 and an oxygen separation device 13. Among them, the mixing device 11, the electrolytic cell 12 and the oxygen separation device 13 constitute a circulation loop, in which electrolyte flows. The electrolyte is electrolyzed into hydrogen and oxygen in the electrolytic cell 12, and the hydrogen is output. The oxygen enters the oxygen separation device 13 together with the remaining electrolyte and is finally separated. The electrolyte flows back to the mixing device 11 after passing through the electrolyte heater 14 and the electrolyte booster pump 15, and then mixes with the supplementary water input by the water supply device 10 to continue to circulate. Among them, the water supply device 10 is also used to remove impurities and dissolved substances in the water, and purify the water input into the mixing device 11 into pure water. After being separated in the oxygen separation device 13, the oxygen is discharged from the system through the dehumidification cooler 16, the dry heat exchanger 17 and the pressure regulating valve 18 for separate collection. The hydrogen produced by electrolysis is collected through the dehumidification cooler 19, the dry heat exchanger 20 and the pressure regulating valve 21.

[0039] In some embodiments, the electrolytic cell 12 is formed by Fig. 9 The monopolar alkaline water electrolysis hydrogen production cell stack shown is formed by connecting multiple electrolytic cells in series in sequence. The electrodes are connected in parallel. The total voltage of the electrolytic cell stack is the same as that of the electrodes of one electrolytic cell, but the total current is very large. The advantages are simple structure, small leakage current, low current density, and easy maintenance.

[0040] In other embodiments, the electrolytic cell 12 may be used as follows Fig.10 The bipolar alkaline water electrolysis hydrogen production cell stack shown has an anode on one side and a cathode on the other side of the same electrode. The electrons generated by the cathode of the electrolytic cell unit are transferred to the anode of the adjacent unit. The entire electrolytic cell stack is equivalent to a series connection of many electrolytic cells, with a large total voltage, small current, and relatively complex maintenance.

[0041] For alkaline water electrolysis hydrogen production cell stack, due to its structural and principle limitations, the operating power of the electrolysis cell stack cannot be less than 30% of the rated power, otherwise, the hydrogen and oxygen concentrations produced by electrolysis hydrogen production are within the explosion limit, which is easy to cause danger. Therefore, in order to ensure the normal operation of the hydrogen production cell stack, nuclear power must bear at least 30% of the rated power of the electrolysis system, and the remaining load can be provided by wind power and photovoltaic power generation.

[0042] In the electrolysis process of alkaline water, a KOH solution with a mass fraction of 25% to 30% is used to avoid corrosion of the electrode material of the electrolytic cell. The electrode material can be made of nickel-based metal. The theoretical electrolysis voltage of the alkaline water electrolysis hydrogen production cell is:

[0043]

[0044] In order for the electrolytic cell reaction to proceed at a practical rate, the cell voltage needs to exceed the theoretical voltage. The actual water electrolysis voltage E cell =E+E ov.pot.A +E ov.pot.C +E ohm , where E ov.pot.A is the anode overvoltage, E ov.pot.C is the cathode overvoltage, E ohm is the ohmic resistance voltage.

[0045] The clean energy electrolysis hydrogen production system provided in the above embodiment combines renewable energy generation with nuclear power based on the volatility of renewable energy, combines the drastically changing electric energy from renewable energy and the surplus electric energy from nuclear power, produces hydrogen through the method of water electrolysis hydrogen production, and converts it into hydrogen energy, which can play the role of storage, average and stable utilization, and peak-shaving and valley-filling of power load. In isolated islands and remote areas, distributed renewable energy generation is used to consume hydrogen locally, without the need for long-distance power output. Water electrolysis hydrogen production can easily produce hydrogen regardless of the scale, and the byproduct oxygen can also be used in industrial production, with the advantages of easy maintenance.

[0046] The purpose of the above embodiments is to further explain the present invention in detail in conjunction with the accompanying drawings so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, the optimization or equivalent replacement of the structure of the parts involved, and the combination of the implementation methods in different embodiments without conflict of structure and principle, all fall within the protection scope of the present invention.

Claims

1. A clean energy electrolysis hydrogen production system, comprising a power supply system and an electrolysis system, characterized in that: The power supply system includes a nuclear power generation device and a new energy power supply device, wherein the new energy power supply device includes one or more photovoltaic power generation devices and / or wind power generation devices, and the power supply of the nuclear power generation device to the electrolysis system is not less than 30% of the rated power of the electrolysis system; The electrolysis system comprises a water supply device, a mixing device, an electrolytic cell and an oxygen separation device, wherein the water supply device supplies water to the mixing device, the mixing device, the electrolytic cell and the oxygen separation device are connected in a closed loop and contain a circulating electrolyte, the mixing device is used to mix the electrolyte with the water input by the water supply device, the electrolytic cell is used to produce hydrogen by electrolysis, and the oxygen separation device is used to separate the oxygen generated by electrolysis; The power supply system is connected to the electrolysis system through a power transmission system to allow the power supply system to supply power to the electrolysis system; wherein the power transmission system includes a plurality of independent AC bus bars, a rectifier and a DC bus bar, the plurality of independent AC bus bars are connected to the rectifier device to allow the rectifier device to convert AC power into DC power, the rectifier device is connected to the DC bus bar, and the DC bus bar is connected to the electrolysis system; the nuclear power generation device and each set of the wind power generation device are respectively connected to the independent AC bus bars, and the photovoltaic power generation device is connected to the independent AC bus bar through an inverter, and the inverter is used to convert the DC power generated by the photovoltaic power generation device into AC power.

2. The clean energy electrolysis hydrogen production system according to claim 1, characterized in that: The independent AC busbars are arranged in parallel.

3. The clean energy electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The new energy power supply device also includes an energy storage battery.

4. The clean energy electrolysis hydrogen production system according to claim 3 is characterized in that: The energy storage battery includes an active power zero control system and a state of charge (SOC) recovery control system.

5. The clean energy electrolysis hydrogen production system according to claim 1 or 2, characterized in that: When the wind power generation device exists in the clean energy electrolysis hydrogen production system, the wind power generation device is configured as a double-fed induction generator.

6. The clean energy electrolysis hydrogen production system according to claim 5, characterized in that: In the dq rotating coordinate system, the rotor-side converter of the doubly-fed induction generator adopts double closed-loop control of an active power outer loop and a current inner loop for the q axis, and adopts single-loop control of a zero reference current for the d axis.

7. The clean energy electrolysis hydrogen production system according to claim 5, characterized in that: In the dq rotating coordinate system, the grid-connected side converter d-axis double closed-loop control adopts a DC bus voltage outer loop and a current inner loop; the q-axis adopts a reactive outer loop and a current inner loop control.

8. The clean energy electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The electrolytic cell is configured as a monopolar alkaline water electrolysis hydrogen production cell stack or a bipolar alkaline water electrolysis hydrogen production cell stack.

9. The clean energy electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The water supply device further comprises a water treatment device, and the water treatment device is used to treat the water input into the mixing device into pure water.

10. The clean energy electrolysis hydrogen production system according to claim 1 or 2, characterized in that: The electrolysis system further includes a dehumidifier and a drying heat exchanger, wherein the dehumidifier and the drying heat exchanger are connected to the electrolysis cell and are used to dry and cool the produced hydrogen.

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