Stable and continuous photovoltaic green ammonia synthesis system

Abstract

The invention relates to a stable and continuous photovoltaic green ammonia synthesis system which comprises a photovoltaic power generation device, a water electrolysis hydrogen production device, a green ammonia synthesis device, an electrochemical energy storage device, a green hydrogen storage tank and a nitrogen production air separation device, the photovoltaic power generation device is simultaneously connected with the power supply ends of the water electrolysis hydrogen production device, the green ammonia synthesis device and the nitrogen production air separation device and the input end of the electrochemical energy storage device through power transmission lines; the electrochemical energy storage device is simultaneously connected with the power supply ends of the green ammonia synthesis device and the nitrogen-making air separation device through power transmission lines; the output end of the water electrolysis hydrogen production device is respectively connected with the input ends of the green hydrogen storage tank and the green ammonia synthesis device through material conveying pipelines; and the input end of the green ammonia synthesis device is also respectively connected with the output ends of the green hydrogen storage tank and the nitrogen-making air separation device through material conveying pipelines. According to the invention, stable and continuous operation of the green ammonia production system under different weather conditions can be ensured, no electricity needs to be purchased, and energy conservation and environmental protection are truly realized.

Description

Technical Field

[0001] The present invention relates to a chemical production system, in particular to a system for producing green ammonia using photovoltaic power supply, specifically to a stable and continuous photovoltaic green ammonia synthesis system. Background Art

[0002] At present, my country's ammonia market is still dominated by fossil fuel synthetic ammonia. In recent years, the country has introduced a series of policies to encourage the development of the green ammonia industry, and proposed to optimize the raw material structure of synthetic ammonia technology to develop green ammonia. Green ammonia blending uses surplus electricity generated by renewable energy to produce hydrogen and synthesize green ammonia through water electrolysis, and implements coal-fired units to blend green ammonia for power generation, replacing part of the coal. The transition of the ammonia market from traditional fossil energy synthetic ammonia to green ammonia has become a general trend, which is also the main driving force for the development of the synthetic ammonia industry.

[0003] my country has initially implemented the production of green hydrogen from water by photovoltaic electrolysis and the synthesis of green ammonia from green hydrogen. However, the conventional structure of the current photovoltaic green ammonia synthesis system mainly includes: power supply unit, water electrolysis hydrogen production unit, nitrogen production unit, storage tank unit, ammonia synthesis unit, etc. Photovoltaic power generation can only be used to meet the power demand of the production equipment under sunny conditions, while at night and in rainy weather, photovoltaic power generation cannot meet the production demand, and external power must be purchased to maintain uninterrupted production operation, which affects the production efficiency of the green ammonia production system and greatly limits the promotion of the system. Summary of the invention

[0004] The purpose of the present invention is to provide a stable and continuous photovoltaic green ammonia synthesis system to address the deficiencies of the prior art, which can ensure that the production system can operate stably and continuously under different weather conditions without the need to purchase electricity, thereby truly achieving energy conservation and environmental protection.

[0005] The technical solution of the present invention is: A stable and continuous photovoltaic green ammonia synthesis system, comprising a photovoltaic power generation device, a water electrolysis hydrogen production device, a green ammonia synthesis device, an electrochemical energy storage device, a green hydrogen storage tank and a nitrogen production air separation device; The photovoltaic power generation device is connected to the power supply end of the water electrolysis hydrogen production device, the green ammonia synthesis device and the nitrogen production air separation device and the electrochemical energy storage device through a power transmission line; The electrochemical energy storage device is connected to the power supply terminals of the green ammonia synthesis device and the nitrogen production air separation device through a power transmission line; The output end of the water electrolysis hydrogen production device is connected to the input ends of the green hydrogen storage tank and the green ammonia synthesis device through a feed pipeline respectively; The input end of the green ammonia synthesis device is also connected to the output ends of the green hydrogen storage tank and the nitrogen production air separation device through feed pipelines.

[0006] Furthermore, it also includes a hydrogen fuel cell device, whose input end is connected to the output end of the green hydrogen storage tank through a feed pipeline, and whose output end is connected to the power supply end of the green ammonia synthesis device through a power transmission line.

[0007] Furthermore, the electrochemical energy storage device is a lithium iron phosphate battery.

[0008] Furthermore, the electrochemical energy storage device comprises two sets, which are arranged in parallel.

[0009] Furthermore, the water electrolysis hydrogen production device is an alkaline water electrolysis hydrogen production device, and its operation flexibility is 30%~110%.

[0010] Furthermore, the water electrolysis hydrogen production device comprises multiple sets, which are arranged in parallel.

[0011] Furthermore, it also includes a heat exchanger, one heat exchange pipeline of which is a hot water pipeline connected to a hot water station or a hot water storage tank, and the other heat exchange pipeline is a circulating water pipeline connected to the water electrolysis hydrogen production device.

[0012] Beneficial effects of the present invention: The present invention has reasonable design, simple structure and convenient control, and can ensure that the green ammonia production system can operate stably and continuously under different weather conditions such as sunny days, rainy days and nights, without the need to purchase electricity, thus ensuring stable production and truly achieving energy conservation and environmental protection, which is conducive to promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0014] Among them, 1-photovoltaic power generation device, 2-water electrolysis hydrogen production device, 3-green ammonia synthesis device, 4-electrochemical energy storage device, 5-green hydrogen storage tank, 6-hydrogen fuel cell device, 7-heat exchanger, 8-nitrogen production air separation device. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0016] like Figure 1 shown.

[0017] A stable and continuous photovoltaic green ammonia synthesis system includes a photovoltaic power generation device 1, a water electrolysis hydrogen production device 2, a green ammonia synthesis device 3, an electrochemical energy storage device 4, a green hydrogen storage tank 7, a nitrogen production air separation device 8, a hydrogen fuel cell device 6 and a heat exchanger 7, etc.

[0018] The photovoltaic power generation device 1 is connected to the power supply terminals of the water electrolysis hydrogen production device 2, the green ammonia synthesis device 3 and the nitrogen production air separation device 8 through a power transmission line, and can provide power to the water electrolysis hydrogen production device 2, the green ammonia synthesis device 3 and the nitrogen production air separation device 8 to maintain their normal operation. At the same time, the photovoltaic power generation device 1 is connected to the electrochemical energy storage device 4 through a power transmission line so as to transmit excess power to the electrochemical energy storage device for storage.

[0019] The electrochemical energy storage device 4 is a lithium iron phosphate battery and an inverter-boost integrated device, which can meet the "charging" and "discharging" requirements according to actual conditions, is easy to use, and has high safety. The electrochemical energy storage device 4 is connected to the power supply end of the green ammonia synthesis device 3 and the nitrogen-making air separation device 8 through a power transmission line at the same time, and can provide power to the green ammonia synthesis device 3 and the nitrogen-making air separation device 8 when the photovoltaic power generation device 1 stops working, ensuring the continuous production.

[0020] Preferably, the electrochemical energy storage device 4 is comprised of two sets, which are connected in parallel to each other, so as to prevent any one set from being damaged and causing a production stoppage accident.

[0021] The water electrolysis hydrogen production device 2 is an alkaline water electrolysis hydrogen production device, and its operational flexibility is 30%~110%. At the same time, in order to achieve stable output of hydrogen, the water electrolysis hydrogen production device 2 is provided with gas-liquid treatment facilities, hydrogen purification facilities, oxygen purification facilities, water replenishment and alkali injection, etc. in addition to the electrolyzer. The output end of the water electrolysis hydrogen production device 2 is connected to the input end of the green hydrogen storage tank 5 and the green ammonia synthesis device 3 through a feed pipeline, respectively, so as to provide sufficient hydrogen raw materials for the green ammonia synthesis device 3, and input the excess hydrogen into the green hydrogen storage tank 5 for storage. Preferably, the water electrolysis hydrogen production device 2 and the green hydrogen storage tank 5 are both multiple, and are arranged in parallel to provide sufficient operational flexibility. The hydrogen production capacity requirement of a single electrolyzer is 1000Nm 3 / h, hydrogen outlet pressure ≥1.5MPag.

[0022] The output end of the green hydrogen storage tank 5 is connected to the input end of the green ammonia synthesis device 3 and the input end of the hydrogen fuel cell device 6 through a feed pipeline, so that the stored hydrogen can be input into the green ammonia synthesis device 3 to provide raw materials for the synthesis reaction of green ammonia. At the same time, the stored hydrogen can also be input into the fuel cell device to provide hydrogen raw materials for the latter to produce electricity.

[0023] The output end of the hydrogen fuel cell device 6 is connected to the power supply end of the green ammonia synthesis device 3 through a power transmission line, so as to provide power for the green ammonia synthesis device.

[0024] The green ammonia synthesis device 3 can use a green ammonia synthesis tower with a lower operating pressure, and its operating pressure is less than 15MPa, so as to reduce energy consumption and equipment requirements. The input end of the green ammonia synthesis device 3 is also connected to the output end of the nitrogen production air separation device 8 through a feed pipeline, so that the nitrogen in the nitrogen production air separation device is input into the green ammonia synthesis device to provide raw materials for the synthesis reaction of green ammonia.

[0025] The heat exchanger 7 includes two heat exchange pipelines, one of which is a hot water pipeline and the other is a circulating water pipeline. One end of the hot water pipeline is external cold water, and the other end is a hot water station or a hot water storage tank. The circulating water circuit is connected to the electrolysis water hydrogen production device, and the waste heat of the circulating water of the electrolysis water hydrogen production device can be utilized. As a result, the high-temperature circulating water generated in the process of electrolysis water hydrogen production can be heat-exchanged with cold water through the heat exchanger, so that the cold water is heated and input into the hot water station or the hot water storage tank. The circulating water after heat exchange is recycled again in the form of return water. Thereby, energy is fully utilized, economic benefits are improved, and energy saving and environmental protection can be achieved. Preferably, the heat exchanger 7 is a plate heat exchanger.

[0026] The working process of the present invention is: 1. Under normal daytime conditions, the photovoltaic power generation device operates at full capacity, supplies power to the water electrolysis hydrogen production device, the green ammonia synthesis device and the nitrogen production air separation device, and stores the excess electricity through the electrochemical energy storage device. At this time, the water electrolysis hydrogen production device, the green ammonia synthesis device and the nitrogen production air separation device are all in full operation. Among them, the water electrolysis hydrogen production device supplies hydrogen to the green ammonia synthesis device to ensure its production needs, and inputs excess hydrogen into the green hydrogen storage tank for storage; the nitrogen production air separation device supplies nitrogen to the green ammonia synthesis device; and the green ammonia synthesis device produces liquid ammonia as a product.

[0027] 2. Under normal nighttime conditions, the photovoltaic power generation device stops working, and the electrochemical energy storage device supplies power to the nitrogen production air separation device and the green ammonia synthesis device to ensure that the green ammonia synthesis device operates at full capacity. At the same time, the water electrolysis hydrogen production device stops working, and the green hydrogen storage tank supplies hydrogen to the green ammonia synthesis device to ensure that the green ammonia synthesis device can produce liquid ammonia normally during the night.

[0028] 3. In extremely rainy conditions, the photovoltaic power generation device stops working, and the electrochemical energy storage device first supplies power to the green ammonia synthesis device and the nitrogen production air separation device, so that the green ammonia synthesis device and the nitrogen production air separation device can operate at reduced load. At the same time, the water electrolysis hydrogen production device stops working, and the green hydrogen storage tank supplies hydrogen to the green ammonia synthesis device to ensure the continuous production of liquid ammonia products. When the power of the electrochemical energy storage device is exhausted, the green hydrogen storage tank starts to supply hydrogen to the hydrogen fuel cell device, so that the hydrogen fuel cell device starts working, and supplies power to the green ammonia synthesis device and the nitrogen production air separation device, so that the green ammonia synthesis device and the nitrogen production air separation device continue to operate at reduced load, ensuring the continuous production of liquid ammonia products.

[0029] The present invention can ensure that the green ammonia production system can operate stably and continuously under different weather conditions such as sunny days, rainy days and nights, without the need to purchase electricity, thereby ensuring stable production and truly achieving energy conservation and environmental protection, which is conducive to promotion.

[0030] The parts not involved in the present invention are the same as the prior art or can be implemented by using the prior art.

Claims

1. A stable and continuous photovoltaic green ammonia synthesis system, characterized by: It includes photovoltaic power generation device, water electrolysis hydrogen production device, green ammonia synthesis device, electrochemical energy storage device, green hydrogen storage tank and nitrogen production air separation device; The photovoltaic power generation device is connected to the power supply end of the water electrolysis hydrogen production device, the green ammonia synthesis device and the nitrogen production air separation device and the electrochemical energy storage device through a power transmission line; The electrochemical energy storage device is connected to the power supply terminals of the green ammonia synthesis device and the nitrogen production air separation device through a power transmission line; The output end of the water electrolysis hydrogen production device is connected to the input ends of the green hydrogen storage tank and the green ammonia synthesis device through a feed pipeline respectively; The input end of the green ammonia synthesis device is also connected to the output ends of the green hydrogen storage tank and the nitrogen production air separation device through feed pipelines.

2. The stable and continuous photovoltaic green ammonia synthesis system according to claim 1 is characterized in that: It also includes a hydrogen fuel cell device, whose input end is connected to the output end of the green hydrogen storage tank through a feed pipeline, and whose output end is connected to the power supply end of the green ammonia synthesis device through a power transmission line.

3. The stable and continuous photovoltaic green ammonia synthesis system according to claim 1 is characterized in that: The electrochemical energy storage device is a lithium iron phosphate battery.

4. The stable and continuous photovoltaic green ammonia synthesis system according to claim 1 is characterized in that: The electrochemical energy storage device comprises two sets, which are arranged in parallel.

5. The stable and continuous photovoltaic green ammonia synthesis system according to claim 1 is characterized in that: The water electrolysis hydrogen production device is an alkaline water electrolysis hydrogen production device, and its operation flexibility is 30% to 110%.

6. The stable and continuous photovoltaic green ammonia synthesis system according to claim 1 is characterized in that: The water electrolysis hydrogen production device comprises multiple sets, which are arranged in parallel.

7. The stable and continuous photovoltaic green ammonia synthesis system according to claim 1 is characterized in that: It also includes a heat exchanger, one of which is a hot water pipeline connected to a hot water station or a hot water storage tank, and the other is a circulating water pipeline connected to the water electrolysis hydrogen production device.

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