A deep peak regulation system and method for a thermal power plant assisted by photovoltaic hydrogen production

Abstract

The present invention relates to a deep peak regulation system and method for a thermal power plant assisted by photovoltaic hydrogen production, comprising a power supply unit, a PEM electrolysis unit, an ALK electrolysis unit, a hydrogen buffer tank and a hydrogen storage unit, wherein the power supply unit comprises a 10kV switch station, wherein the 10kV switch station is respectively connected to a thermal power plant, an inverter A and an inverter B through wires, wherein the inverter A is connected to a photovoltaic module of group A, and the inverter B is connected to a photovoltaic module of group B; the PEM electrolysis unit comprises a DC / DC converter, wherein the DC / DC converter is sequentially connected to a PEM electrolyzer; the ALK electrolysis unit comprises an AC / DC rectifier, wherein the AC / DC rectifier is sequentially connected to an ALK electrolyzer; the hydrogen storage unit comprises a diaphragm compressor and a hydrogen storage tank connected in sequence; and the 10kV switch station is connected to the AC / DC rectifier through wires. The solar energy is fully and efficiently converted into electric energy to the greatest extent, and then used in the hydrogen production process, thereby realizing full utilization of renewable energy.

Description

Technical Field

[0001] The present invention relates to the technical field of renewable energy hydrogen production system optimization, and in particular to a deep peak regulation system and method for a thermal power plant assisted by photovoltaic hydrogen production. Background Art

[0002] Hydrogen energy is a carbon-free green energy and a highly potential secondary energy source. It will occupy an important position in the future energy system. The "Medium- and Long-Term Plan for the Development of the Hydrogen Energy Industry" (2021-2035) points out that the hydrogen energy industry is a strategic emerging industry and a key development direction for future industries. It clarifies the energy attributes of hydrogen, puts forward the basic principles for the development of the hydrogen energy industry and the goals for each stage of development, and deploys important measures to promote the high-quality development of the hydrogen energy industry. Hydrogen energy is an important part of the future national energy system and an important carrier for energy users to achieve green and low-carbon transformation. The hydrogen energy industry is a strategic emerging industry and a key development direction for future industries.

[0003] In the electrolysis system of the hydrogen production station: according to the working environment of the water electrolysis hydrogen production system and the type of diaphragm used in the electrolyzer, the water electrolysis hydrogen production technology is mainly divided into four types: alkaline water electrolysis (ALK), proton exchange membrane (PEM) water electrolysis, solid polymer anion exchange membrane (AEM) water electrolysis, and solid oxide (SOEC) water electrolysis.

[0004] With the help of the peak-shaving capacity of thermal power units, the randomness and volatility of renewable energy power can be effectively smoothed out, and the reliability and safety of the power transmitted from the renewable energy base can be improved. However, the problems existing in the peak-shaving of thermal power plants are as follows: 1. The problem of limited self-regulation capacity; the lack of peak-shaving capacity cannot effectively handle the large amount of abandoned power generated by renewable energy power generation, and cannot fully solve the problem of excess power generated by renewable energy power during peak periods; it is difficult to fully adapt to the randomness and volatility of renewable energy power; although it has a certain effect in peak-shaving, it is difficult to ensure the reliability and safety of the power transmitted from the renewable energy base in the face of the unstable characteristics of renewable energy power generation; 2. Relying solely on peak-shaving of thermal power plants may lead to high operating costs; when thermal power plants frequently perform peak-shaving operations, it may affect the service life and operating efficiency of equipment, thereby increasing maintenance costs and energy consumption; energy waste may occur during peak-shaving; due to the limitations of its peak-shaving method, when responding to changes in renewable energy power, it may not be possible to achieve efficient use of energy, resulting in a certain degree of waste. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a deep peak-shaving system and method for thermal power plants assisted by photovoltaic hydrogen production, which utilizes photovoltaic hydrogen production combined with a flexible transformation method for deep peak-shaving of power plants, and utilizes photovoltaics, a clean and renewable energy source, to the greatest extent possible, fully and efficiently convert solar energy into electrical energy, which is then used in the hydrogen production process, thereby achieving full utilization of renewable energy. The thermal power plant increases its deep peak-shaving capacity below the minimum technical output by "hydrogen production".

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A deep peak-shaving system for a thermal power plant assisted by photovoltaic hydrogen production, comprising a power supply unit, a PEM electrolysis unit, an ALK electrolysis unit, a hydrogen buffer tank and a hydrogen storage unit, wherein the power supply unit comprises a 10kV switch station, wherein the 10kV switch station is respectively connected to a thermal power plant, an inverter A and an inverter B through wires, wherein the inverter A is connected to a group A of photovoltaic modules, and the inverter B is connected to a group B of photovoltaic modules;

[0008] The PEM electrolysis unit includes a DC / DC converter, which is sequentially connected to a PEM electrolytic cell, a PEM gas-liquid processor, and a PEM purification device;

[0009] The ALK electrolysis unit includes an AC / DC rectifier, which is sequentially connected to an ALK electrolytic cell, an ALK gas-liquid processor, and an ALK purification device;

[0010] The hydrogen storage unit comprises a diaphragm compressor and a hydrogen storage tank connected in sequence;

[0011] The 10kV switch station is connected to the AC / DC rectifier through a wire; the B group photovoltaic module is also connected to the DC / DC converter through a wire; the air inlet of the hydrogen buffer tank is connected to the PEM purification device and the ALK purification device respectively through an air pipe, and the air outlet is connected to the diaphragm compressor through an air pipe.

[0012] The PEM electrolysis unit also includes a PEM auxiliary system, and the PEM auxiliary system is connected to the PEM electrolysis tank and the PEM gas-liquid processor respectively through water pipes.

[0013] The ALK electrolysis unit also includes an ALK auxiliary system, which is connected to the ALK electrolysis tank and the ALK gas-liquid processor respectively through water pipes.

[0014] A peak-shaving method based on a photovoltaic hydrogen production-assisted thermal power plant deep peak-shaving system comprises the following steps:

[0015] S1, A group of photovoltaic modules generate direct current , direct current Converge to inverter A, DC Converted into AC power by inverter A , and then sent to the 10kV switch station through the conductive line;

[0016] S2. At the same time as step S1, the photovoltaic modules of group B generate direct current , direct current A portion of it is sent to the DC / DC converter, which converts the DC power The voltage is converted into the PEM electrolyzer working voltage for the operation of the PEM electrolyzer;

[0017] The hydrogen and oxygen generated by the operation of the PEM electrolyzer are transported to the PEM gas-liquid processor through pipelines. The hydrogen after separation is sent to the PEM purification device. The hydrogen purified by the PEM purification device is sent to the hydrogen buffer tank through pipelines.

[0018] S3. At the same time as step S2, the remaining DC Converge to inverter B, and then convert into AC power , and then sent to the 10kV switch station through conduction, and the 10kV switch station transmits AC To AC / DC rectifier, AC Converted into DC power by AC / DC rectifier , direct current Powering the ALK electrolyzer;

[0019] The hydrogen and oxygen generated by the operation of the ALK electrolyzer are transported to the ALK gas-liquid processor through pipelines, and the separated hydrogen is sent to the ALK purification device. The hydrogen purified by the ALK purification device is sent to the hydrogen buffer tank through pipelines;

[0020] S4. In step S3, when the photovoltaic power generation is greater than the power required for hydrogen production, the 10kV switch station transmits the excess electricity to the thermal power plant; when the photovoltaic power generation is less than the power required for hydrogen production, the power of the thermal power plant is transmitted to the 10kV switch station, and the 10kV switch station transmits the power to the AC / DC rectifier to power the ALK electrolyzer;

[0021] S5. When the thermal power plant needs deep peak regulation, the excess electricity is transmitted to the 10kV switch station of the hydrogen production station through the thermal power plant for hydrogen production;

[0022] S6. The hydrogen in the hydrogen buffer tank is stored in a hydrogen storage tank through a diaphragm compressor and transported out by a trailer.

[0023] The beneficial effects of the present invention are:

[0024] 1. Hydrogen production through PEM and ALK can effectively smooth out the randomness and volatility of new energy electricity, improve the reliability and safety of power transmission from new energy bases, and assist thermal power units in peak load regulation. By constructing a photovoltaic hydrogen-fired storage multi-energy complementary system and utilizing the long-term and flexible peak-shaving capability of the hydrogen production system, the problem of new energy consumption and deep peak load regulation of thermal power plants can be effectively solved. Moreover, if only abandoned electricity is used to produce hydrogen or only photovoltaic hydrogen is used, the operating hours of the hydrogen production system are usually low, and it is difficult to ensure the economy of the hydrogen production system. Therefore, the flexible adjustment capability of the hydrogen production system is utilized, and thermal power and energy storage units are coordinated to increase the effective utilization hours of the hydrogen production system. This can not only improve the utilization rate of new energy, but also improve the economy of the hydrogen production system. How to dispatch and optimize the photovoltaic, hydrogen production, and thermal power multi-energy complementary system to simultaneously meet the peak power supply, improve the utilization rate of new energy, and ensure the economy of hydrogen production.

[0025] 2. The flexible transformation method of combining photovoltaic hydrogen production with deep peak regulation of power plants, on the one hand, utilizes photovoltaics, a clean and renewable energy, to the greatest extent possible, fully and efficiently convert solar energy into electrical energy, which is then used in the hydrogen production process, thereby fully utilizing renewable energy; on the other hand, through reasonable allocation and control, it provides strong peak regulation support for the operation of thermal power plants, effectively balances electricity supply and demand, enhances the stability and flexibility of the power grid, and expands the peak regulation capacity of thermal power plants, enabling them to better adapt to changes in power load and ensure the safe and stable operation of the power system.

[0026] 3. The PEM electrolyzer is directly connected to the B group of photovoltaic modules through a DC / DC converter, avoiding the loss of power generation caused by AC / DC conversion. Since the DC power consumption, startup time, and dynamic response speed of the PEM electrolyzer are better than those of the ALK electrolyzer, it can better adapt to the unstable fluctuations of photovoltaic power generation. Compared with the DC / DC+AC / DC combined power supply, the AC / DC conversion steps are reduced, thereby reducing the energy loss caused by on-resistance and switching loss, and also reducing the use of cables and other wiring materials, thereby reducing transmission losses. The DC hydrogen supply method can reduce energy losses by 1%~5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of photovoltaic hydrogen production to assist thermal power plants in deep peak regulation. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0029] Example 1

[0030] like Figure 1As shown, a deep peak-shaving system for a thermal power plant assisted by photovoltaic hydrogen production includes a power supply unit, a PEM electrolysis unit, an ALK electrolysis unit, a hydrogen buffer tank and a hydrogen storage unit. The power supply unit includes a 10kV switch station, and the 10kV switch station is respectively connected to a thermal power plant, an inverter A and an inverter B through wires. The inverter A is connected to a group A of photovoltaic modules, and the inverter B is connected to a group B of photovoltaic modules.

[0031] The PEM electrolysis unit includes a DC / DC converter, which is sequentially connected to a PEM electrolytic cell, a PEM gas-liquid processor, and a PEM purification device;

[0032] The ALK electrolysis unit includes an AC / DC rectifier, which is sequentially connected to an ALK electrolytic cell, an ALK gas-liquid processor, and an ALK purification device;

[0033] The hydrogen storage unit comprises a diaphragm compressor and a hydrogen storage tank connected in sequence;

[0034] The 10kV switch station is connected to the AC / DC rectifier through a wire; the B group photovoltaic module is also connected to the DC / DC converter through a wire; the air inlet of the hydrogen buffer tank is connected to the PEM purification device and the ALK purification device respectively through an air pipe, and the air outlet is connected to the diaphragm compressor through an air pipe.

[0035] The PEM electrolysis unit also includes a PEM auxiliary system, and the PEM auxiliary system is connected to the PEM electrolysis tank and the PEM gas-liquid processor respectively through water pipes.

[0036] The ALK electrolysis unit also includes an ALK auxiliary system, which is connected to the ALK electrolysis tank and the ALK gas-liquid processor respectively through water pipes.

[0037] A peak-shaving method based on a photovoltaic hydrogen production-assisted thermal power plant deep peak-shaving system comprises the following steps:

[0038] S1, A group of photovoltaic modules generate direct current , direct current Converge to inverter A, DC Converted into AC power by inverter A , and then sent to the 10kV switch station of the hydrogen production station through the conductive line;

[0039] S2. At the same time as step S1, the photovoltaic modules of group B generate direct current , direct current A portion of it is sent to the DC / DC converter, which converts the DC power The voltage is converted into the PEM electrolyzer working voltage for the operation of the PEM electrolyzer;

[0040] The hydrogen and oxygen generated by the operation of the PEM electrolyzer are transported to the PEM gas-liquid processor through pipelines. The hydrogen after separation is sent to the PEM purification device. The hydrogen purified by the PEM purification device is sent to the hydrogen buffer tank through pipelines.

[0041] S3. At the same time as step S2, the remaining DC Converge to inverter B, and then convert into AC power , and then sent to the 10kV switch station of the hydrogen production station through conduction, and the 10kV switch station of the hydrogen production station transmits AC To AC / DC rectifier, AC Converted into DC power by AC / DC rectifier , direct current Powering the ALK electrolyzer;

[0042] The hydrogen and oxygen generated by the operation of the ALK electrolyzer are transported to the ALK gas-liquid processor through pipelines, and the separated hydrogen is sent to the ALK purification device. The hydrogen purified by the ALK purification device is sent to the hydrogen buffer tank through pipelines;

[0043] S4. In step S3, when the power generation of photovoltaic (PV modules of group A and PV modules of group B) is greater than the power consumption required for hydrogen production, the 10kV switch station of the hydrogen production station transmits the excess power to the thermal power plant; when the power generation of photovoltaic is less than the power consumption required for hydrogen production, the power consumption of the thermal power plant is transmitted to the 10kV switch station of the hydrogen production station, and the 10kV switch station of the hydrogen production station transmits the power consumption to the AC / DC rectifier to supply power to the ALK electrolyzer;

[0044] S5. When the thermal power plant needs deep peak regulation, the excess electricity is transmitted to the 10kV switch station of the hydrogen production station through the thermal power plant for hydrogen production;

[0045] S6. The hydrogen in the hydrogen buffer tank is stored in a hydrogen storage tank through a diaphragm compressor and transported out by a trailer.

[0046] The PEM auxiliary system includes: pure water replenishment device, refrigeration unit, circulating cooling water device, nitrogen generator module (shared with ALK electrolyzer auxiliary system), compressed air module (shared with ALK electrolyzer auxiliary system), etc.

[0047] The ALK auxiliary system includes a pure water replenishment device, an alkaline water device, a refrigeration unit and a circulating cooling water device.

[0048] Producing hydrogen through PEM and ALK can effectively smooth out the randomness and volatility of new energy electricity, improve the reliability and safety of power transmission from new energy bases, and assist thermal power units in peak load regulation. By constructing a photovoltaic hydrogen-fired storage multi-energy complementary system and utilizing the long-term and flexible peak-shaving capability of the hydrogen production system, the problem of new energy consumption and deep peak load regulation of thermal power plants can be effectively solved. Moreover, if only abandoned electricity is used to produce hydrogen or only photovoltaic hydrogen is used, the operating hours of the hydrogen production system are usually low, making it difficult to ensure the economy of the hydrogen production system. Therefore, the flexible adjustment capability of the hydrogen production system is utilized, in conjunction with thermal power and energy storage units, to increase the effective utilization hours of the hydrogen production system. This can not only improve the utilization rate of new energy, but also improve the economy of the hydrogen production system. It is important to optimize the scheduling of photovoltaic, hydrogen production, and thermal power multi-energy complementary systems to simultaneously meet the peak power supply, improve the utilization rate of new energy, and ensure the economy of hydrogen production.

[0049] The flexible transformation method of combining photovoltaic hydrogen production with deep peak regulation of power plants, on the one hand, utilizes photovoltaics, a clean and renewable energy, to the greatest extent possible, fully and efficiently convert solar energy into electrical energy, which is then used in the hydrogen production process, thereby fully utilizing renewable energy; on the other hand, through reasonable allocation and control, it provides strong peak regulation support for the operation of thermal power plants, effectively balances electricity supply and demand, enhances the stability and flexibility of the power grid, and expands the peak regulation capacity of thermal power plants, enabling them to better adapt to changes in power load and ensure the safe and stable operation of the power system.

[0050] The PEM electrolyzer uses a DC / DC converter to directly connect the B group of photovoltaic modules, avoiding the loss of power generation caused by AC / DC conversion. Since the DC power consumption, startup time, and dynamic response speed of the PEM electrolyzer are better than those of the ALK electrolyzer, it can better adapt to the unstable fluctuations of photovoltaic power generation. Compared with the DC / DC+AC / DC combined power supply, it reduces the AC / DC conversion steps, thereby reducing the energy loss caused by on-resistance and switching loss, and also reduces the use of cables and other wiring materials, thereby reducing transmission losses. The DC hydrogen supply method can reduce energy loss by 1%~5%.

[0051] Since the dynamic response speed of the ALK electrolyzer is slightly inferior to that of the PEM electrolyzer, there will be problems with safe and stable operation if photovoltaic modules are directly connected to the ALK electrolyzer; the electrolyzer auxiliary system also needs to use AC power supply. When the thermal power plant has a photovoltaic reverse power supply demand, the photovoltaic DC power needs to be inverted into AC power supply; therefore, the B photovoltaic module is connected to the AC / DC rectifier through the inverter and the 10kV switch station, and part of the DC power generated is converted into AC power, which is uniformly allocated by the 10kV switch station of the hydrogen production station according to the power allocation needs of the plant area. The ALK electrolyzer uses AC / DC power supply, which is more conducive to the safe and stable operation of the ALK electrolyzer.

[0052] The coordinated use of AC / DC power supply for ALK electrolyzers and DC / DC power supply for PEM electrolyzers can fully and efficiently utilize photovoltaic power generation resources to form a resistant hybrid system solution that can take into account both photovoltaic power generation utilization and deep peak regulation needs of thermal power plants.

[0053] Example 2

[0054] Depending on the working environment of the water electrolysis hydrogen production system and the type of diaphragm used in the electrolyzer, the water electrolysis hydrogen production technology is mainly divided into four types: alkaline water electrolysis (ALK), proton exchange membrane (PEM) water electrolysis, solid polymer anion exchange membrane (AEM) water electrolysis, and solid oxide (SOEC) water electrolysis.

[0055] Among the above four water electrolysis hydrogen production technologies, ALK is the earliest industrialized water electrolysis technology with more than 70 years of application experience and is the most mature. From the initial aerospace to the later hydrogen cooling of thermal power plants, to the current large-scale renewable energy coupled hydrogen production projects, most of them have adopted ALK technology; its main application advantages are:

[0056] 1) The technical route is mature.

[0057] 2) Low manufacturing and application costs. The cost of an ALK electrolyzer of the same unit size is only about 25% of that of a PEM electrolyzer. The disadvantages are low electrolysis efficiency, slow cold start speed, and unsuitability for frequent start and stop scenarios, which also makes it difficult to directly couple with new energy power systems with rapidly fluctuating characteristics.

[0058] Compared with ALK electrolyzers, PEM electrolyzers have a more compact equipment structure and higher electrolysis efficiency; the working mode is more flexible and has better adaptability to "green electricity"; the hydrogen produced is of higher purity and only requires the removal of a small amount of water vapor; it has greater resistance to differential pressure and a wider pressure control range; based on these advantages, PEM technology has rapidly emerged and been promoted in recent years; however, it should be noted that the bottleneck of PEM water electrolysis to produce hydrogen lies in its cost and lifespan; in terms of cost, it is currently about four times that of ALK electrolyzers of the same single-unit scale.

[0059] By analyzing the annual output curve of photovoltaic power generation, the annual output curve of thermal power plant generators and the plant power load curve, a power generation output model operation model is constructed, the deep peak regulation demand of the thermal power plant is analyzed, the scale of the hydrogen production system is calculated, and the ratio of PEM electrolyzers and ALK electrolyzers is optimized, that is, the demand for group A photovoltaic modules and group B photovoltaic modules is determined.

[0060] The purity of the produced hydrogen can reach 99.999%. Different storage and transportation methods are considered according to the hydrogen usage scenario and the distance between the user end and the hydrogen station, such as gas storage, low-temperature liquid storage, organic liquid storage, and solid material storage. The hydrogen exported and sold can be used in chemical synthesis of ammonia and methanol, steel smelting, heavy oil refining and other scenarios. It can also be used for hydrogen cooling of generators in thermal power plants.

[0061] (1) AC / DC rectifier

[0062] Convert AC power to DC power through AC / DC rectifier Output, used to electrolyze water to produce hydrogen, the ALK electrolysis unit uses an AC / DC rectifier (as shown in Table 1), an ALK electrolyzer (as shown in Table 2), an ALK gas-liquid processor (as shown in Table 3) and an ALK hydrogen purification device (as shown in Table 4).

[0063] Table 1 is the AC / DC rectifier technical parameters

[0064]

[0065] Table 2 is the technical parameters of 1000Nm³ / h alkaline electrolyzer

[0066]

[0067] Table 3 is the technical parameters of the 1000Nm³ / h gas-liquid processor

[0068]

[0069] Table 4 is the technical parameters of the 1000Nm³ / h hydrogen purification device

[0070]

[0071] (2) DC / DC converter

[0072] The DC / DC converter converts part of the DC The voltage is converted into the working voltage of the PEM electrolyzer so that the power supply is adapted to the voltage requirement of the PEM electrolyzer. The PEM electrolysis unit adopts a DC / DC converter (as shown in Table 5), a PEM electrolyzer (as shown in Table 6), a PEM gas-liquid processor (as shown in Table 7) and a PEM purification device (as shown in Table 8).

[0073] Table 5 is the technical parameter table of DC / DC converter

[0074]

[0075] Table 6 is the technical parameters of 500Nm³ / h PEM electrolyzer

[0076]

[0077] Table 7 is the technical parameters of 500Nm³ / h gas-liquid processor

[0078]

[0079] Table 8 is the technical parameters of 500Nm³ / h hydrogen purification device

[0080]

[0081] If the user is far away from the hydrogen production station, the hydrogen in the hydrogen buffer tank is compressed into a high-pressure hydrogen storage tank through a diaphragm compressor. The high-pressure hydrogen is then used to inflate the hydrogen long-tube trailer through the hydrogen pipeline bus. The hydrogen is then delivered to the user by car in the form of tubes or bottles.

[0082] If it is used directly in a thermal power plant or the user is close to the hydrogen production station, the hydrogen in the hydrogen buffer tank is compressed into the hydrogen storage tank through a diaphragm compressor, the hydrogen is stored in the hydrogen storage tank, and the hydrogen pipeline is directly delivered to the user end.

[0083] The 10kV switch station of the hydrogen production station provides stable power supply for the PEM electrolyzer auxiliary system and the ALK electrolyzer auxiliary system to avoid the instability of photovoltaic power generation and ensure the safe and stable operation of the PEM electrolysis system and the ALK electrolysis system.

[0084] The PEM electrolyzer auxiliary system is connected to the PEM electrolyzer to provide pure water circulation for the PEM electrolyzer. The PEM electrolyzer auxiliary system also includes auxiliary systems such as a desalted water replenishment system, a chilled water system, and a compressed air system to provide pure water circulation for the PEM electrolyzer.

[0085] The ALK electrolyzer auxiliary system is connected to the ALK electrolyzer to provide alkali solution circulation for the ALK electrolyzer. The ALK electrolyzer auxiliary system also includes auxiliary systems such as a desalted water replenishment system, an alkali solution preparation system, a chilled water system, and a compressed air system.

[0086] The oxygen purity produced by the PEM electrolysis unit and the ALK electrolysis unit is 99.5%. The oxygen can be used in the fields of materials, oxygen-enriched combustion, chemical production, etc. According to the user's demand for oxygen quality, the oxygen can be further purified to increase the purity of the oxygen.

[0087] When the thermal power plant is a supercritical unit or above, the produced oxygen can be used in the unit's condensate and feed water oxygenation treatment system after purification.

[0088] The water supply oxygenation system includes: an oxygen buffer tank, an oxygen compressor, a high-pressure oxygen storage tank, an oxygenation bus and connecting pipes.

[0089] By-product oxygen utilization system: The electrolyzer produces oxygen, which passes through the hydrogen purification device to remove hydrogen from the oxygen, and is then transported to the oxygen buffer tank by pipeline. The oxygen is pressurized by the oxygen compressor and stored in a high-pressure oxygen tank. The outlet of the high-pressure oxygen tank is connected to the busbar of the original oxygenation system of the thermal power plant, and finally the oxygen is transported to the condensate jellyfish pipe and the deaerator feed pump downcomer through a pipeline.

[0090] Using electrolysis to produce hydrogen can provide thermal power plants with sufficient oxygen and promote oxygen-rich combustion, which can further achieve the goal of low-load operation of power plants, improve power generation efficiency, reduce coal consumption, reduce the emission of polluting waste, and achieve the effect of energy conservation and emission reduction.

[0091] In order to monitor the system and control operation, an integrated intelligent control system is adopted. The system is equipped with necessary online instruments, such as pressure gauges, thermometers, flow meters, gas analysis instruments, etc., to control the working temperature, working pressure and hydrogen-oxygen separator liquid level of the electrolyzer; sound and light alarms are given for excessive working temperature of the electrolyzer, excessive working pressure, upper / lower limit of the hydrogen-oxygen separator liquid level, lower limit of the alkali liquid circulation volume on the hydrogen and oxygen side, lower limit of the hydrogen and oxygen gas purity, lower limit of the gas source pressure, and rectifier system failure; interlocking is performed for excessive working temperature of the electrolyzer, excessive working pressure, upper / lower limit of the hydrogen-oxygen separator liquid level, lower limit of the alkali liquid circulation volume, and rectifier system failure. Different instruments are used to send signals for the alarm and interlocking of important parameters of the hydrogen production equipment operation. For example, in the pressure regulation system, the alarm is sent by the pressure transmitter, and the interlocking is sent by the on-site electric contact pressure gauge.

[0092] The integrated intelligent control system enables the entire hydrogen production system to operate in a fully automatic mode. By acquiring photovoltaic power generation and plant power consumption, it builds a power balance among thermal power plants, photovoltaic and hydrogen energy facilities, solves the problems of large volatility of renewable energy and deep peak regulation of thermal power plants, and improves energy utilization efficiency. Ultimately, the power generation system and controllable hydrogen load are reasonably coordinated to ensure the quality of electricity and improve the economy of power generation. At the same time, data transmission and regulation are required. Therefore, sensors and smart meters and other equipment need to be installed in the system to collect energy equipment data in real time and transmit it to the centralized control center. Through the data analysis and control technology of the control system, the collected data is analyzed and processed to optimize the control and scheduling of energy equipment. Finally, through communication and network technology, information coordination and transmission of each link are ensured, thereby achieving efficient system operation.

[0093] Combining the dynamic operation response characteristics of ALK electrolyzers and PEM electrolyzers, the flexible consumption of fluctuating photovoltaic power generation output and the problems of new energy storage, deep peak regulation and efficient frequency regulation faced by thermal power plants can be realized. ALK electrolyzers and PEM electrolyzers are jointly operated and regulated in stages to make full use of the characteristics of electrolyzer start-up time and response speed, broaden the system operating range, and the minimum load operating range can reach 0.5%, thereby improving the system's dynamic response capability and energy utilization rate.

[0094] This is achieved by dynamically adjusting the operating status of the hydrogen production equipment, quickly responding to and deeply peaking, combining the working requirements of the hydrogen production end, hydrogen storage end and energy input end, realizing the energy management function and coordinated control among the three, so as to optimize the energy of the entire system. According to the production target required by the user, the photovoltaic output of the site, the grid electricity price and the operating time period, the system operation strategy is comprehensively determined, and dynamically adjusted according to the daily forecast data; by collecting and analyzing seasonal and weather data, the model prediction is used to estimate the hydrogen production output, and the expected hydrogen production output is notified to downstream users in advance; using accurate meteorological forecasts and energy management systems, the operating time and power of the hydrogen production equipment are reasonably arranged to maximize the use of renewable energy output, realize the monitoring and data storage of the overall hydrogen production system operation, ensure the full visualization of the site, and facilitate real-time monitoring and historical data analysis.

[0095] The PEM electrolyzer is directly connected to the photovoltaic power plant through a DC / DC converter, avoiding the loss of power generation caused by AC / DC conversion. At the same time, the coordinated use of the PEM electrolyzer and the ALK electrolyzer can fully adapt to the unstable fluctuations of photovoltaic power generation.

[0096] Thermal power plants require deep peak load shifting periods at night, and power abandonment during this period can be avoided by running ALK electrolysis units.

[0097] As a new type of energy storage, hydrogen energy can be leased and used within the region after being approved by the power technical supervision agency, creating economic benefits for hydrogen production stations.

[0098] The oxygen byproduct of hydrogen production by electrolysis of water is fully utilized and used in the condensate and feed water oxygenation systems of supercritical and above thermal power plant units, which solves the current problem of direct discharge and waste of oxygen byproduct of hydrogen production by electrolysis of water, and saves the oxygenation costs of thermal power plant operation.

[0099] Combining abandoned electricity and photovoltaic green electricity to produce hydrogen not only improves energy utilization and reduces investment in hydrogen production equipment, but also increases the annual utilization hours of hydrogen production equipment. It has good economic benefits and a certain carbon reduction effect.

[0100] The function of the 10kV switch station of the hydrogen production station is to collect electricity and uniformly allocate it according to electricity demand through an integrated intelligent control system. In addition to the DC / DC converter using direct DC power supply from group B photovoltaic modules, the PEM electrolyzer auxiliary system, AC / DC rectifier, ALK auxiliary system, diaphragm compressor, oxygen compressor and integrated intelligent control system are all provided with AC power by the 10kV switch station of the hydrogen production station.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A deep peak-shaving system for a thermal power plant assisted by photovoltaic hydrogen production, comprising a power supply unit, a PEM electrolysis unit, an ALK electrolysis unit, a hydrogen buffer tank and a hydrogen storage unit, characterized in that: The power supply unit includes a 10kV switch station, the 10kV switch station is respectively connected to a thermal power plant, an inverter A and an inverter B through wires, the inverter A is connected to a group A of photovoltaic modules, and the inverter B is connected to a group B of photovoltaic modules; The PEM electrolysis unit includes a DC / DC converter, which is sequentially connected to a PEM electrolytic cell, a PEM gas-liquid processor, and a PEM purification device; The ALK electrolysis unit includes an AC / DC rectifier, which is sequentially connected to an ALK electrolytic cell, an ALK gas-liquid processor, and an ALK purification device; The hydrogen storage unit comprises a diaphragm compressor and a hydrogen storage tank connected in sequence; The 10kV switch station is connected to the AC / DC rectifier through a wire; the B group photovoltaic assembly is also connected to the DC / DC converter through a wire; the air inlet of the hydrogen buffer tank is connected to the PEM purification device and the ALK purification device through an air pipe, and the air outlet is connected to the diaphragm compressor through an air pipe; The peak-shaving steps of the deep peak-shaving system of photovoltaic hydrogen production assisted thermal power plants are as follows: S1, A group of photovoltaic modules generate direct current IDC1, which is converged to inverter A, converted into alternating current IAC1 by inverter A, and then sent to the 10kV switch station through the conductive line; S2, at the same time as step S1, the photovoltaic modules of group B generate direct current IDC2, a part of which is transmitted to the DC / DC converter, and the voltage of the direct current IDC2 is converted into the working voltage of the PEM electrolyzer by the DC / DC converter, which is used for the operation of the PEM electrolyzer; The hydrogen and oxygen generated by the operation of the PEM electrolyzer are transported to the PEM gas-liquid processor through pipelines. The hydrogen after separation is sent to the PEM purification device. The hydrogen purified by the PEM purification device is sent to the hydrogen buffer tank through pipelines. S3. At the same time as step S2, the remaining DC power IDC2 is converged to the inverter B, converted into AC power IAC2 by the inverter B, and then sent to the 10kV switch station through conduction. The 10kV switch station transmits the AC power IAC2 to the AC / DC rectifier. The AC power IAC2 is converted into DC power IDC3 by the AC / DC rectifier. The DC power IDC3 supplies power to the ALK electrolyzer; The hydrogen and oxygen generated by the operation of the ALK electrolyzer are transported to the ALK gas-liquid processor through pipelines, and the separated hydrogen is sent to the ALK purification device. The hydrogen purified by the ALK purification device is sent to the hydrogen buffer tank through pipelines; S4. In step S3, when the photovoltaic power generation is greater than the power required for hydrogen production, the 10kV switch station transmits the excess electricity to the thermal power plant; when the photovoltaic power generation is less than the power required for hydrogen production, the power of the thermal power plant is transmitted to the 10kV switch station, and the 10kV switch station transmits the power to the AC / DC rectifier to power the ALK electrolyzer; S5. When the thermal power plant needs deep peak regulation, the excess electricity is transmitted to the 10kV switch station of the hydrogen production station through the thermal power plant for hydrogen production; S6. The hydrogen in the hydrogen buffer tank is stored in a hydrogen storage tank through a diaphragm compressor and transported out by a trailer.

2. A deep peak regulation system for a thermal power plant assisted by photovoltaic hydrogen production as claimed in claim 1, characterized in that: The PEM electrolysis unit also includes a PEM auxiliary system, and the PEM auxiliary system is connected to the PEM electrolysis tank and the PEM gas-liquid processor respectively through water pipes.

3. A deep peak regulation system for a thermal power plant assisted by photovoltaic hydrogen production as claimed in claim 1, characterized in that: The ALK electrolysis unit also includes an ALK auxiliary system, which is connected to the ALK electrolytic tank and the ALK gas-liquid processor respectively through water pipes.

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