Ammonia on-line decomposition hydrogen production and hydrogenation integrated station

Abstract

According to the invention, an ammonia on-line decomposition hydrogen production technology is adopted, the raw material gas only needs to depend on a mature liquid ammonia storage and transportation commercial network, a green ammonia source can be obtained from regions rich in green electricity resources such as green wind power, photovoltaic power and the like, and the problems of non-uniform distribution of natural resources and hydrogen transportation are thoroughly solved. Mainly aims to provide an ammonia on-line hydrogen production and hydrogenation integrated station which solves the problems of remote transportation, storage and filling of hydrogen, is an amphibious public hydrogen filling station and is suitable for filling of steel cylinder containers and vehicles and ships under different working pressures of 35 MPa and 70 MPa. The core unit of the scheme is that the ammonia decomposition hydrogen production reaction tank and the membrane separator are used for purification, and the compressor, the buffer tank, the hydrogenation gun and the like are matched, so that the positive promotion effect on popularization and application of hydrogen energy is achieved.

Description

Technical Field

[0001] The present invention relates to the application field of ammonia-hydrogen fusion. It is based on the already mature hydrogen fuel cell industry, fundamentally solves the problem of terminal hydrogen use, eliminates the problems of long-distance transportation, storage and refueling of hydrogen, and is a public hydrogen refueling station that can meet both amphibious and water uses. Background Art

[0002] As an important tool for building a clean, low-carbon, safe and efficient energy system, hydrogen energy has steadily gained attention around the world, and the development of hydrogen energy has become a global energy strategy consensus. By the end of 2023, more than 50 countries and regions around the world, including China, have issued national hydrogen energy development strategies and put forward medium- and long-term goals for the development and utilization of hydrogen energy. Under the dual requirements of actively responding to climate change and coping with the energy crisis, countries and regions such as Europe, the United States, Japan and South Korea have accelerated the formulation of carbon emission standards for different types of hydrogen energy, further improved hydrogen energy development goals, and issued and updated a series of goals, plans and policies to promote the rapid development of the hydrogen energy industry. Starting from the fields of transportation and power generation, they focus on the layout of key hydrogen energy technology breakthroughs and advanced product development, systematically standardize international standards for the hydrogen energy industry, coordinate the construction of the hydrogen energy supply chain, and promote the industrialization of hydrogen energy applications and related technologies, aiming to seize the commanding heights of hydrogen energy industry development.

[0003] Hydrogen and ammonia are the ultimate fuels for achieving zero carbon emissions. The difficulty in hydrogen storage and transportation and poor safety are the main "bottlenecks" restricting the development of the hydrogen energy industry. Ammonia, as an efficient hydrogen storage medium, has significant advantages: (1) High energy density. The volume energy density of ammonia is about 13.6 MJ·L-1, 1L of liquid ammonia = 4.5L of high-pressure hydrogen (35.0MPa) = 1200L of hydrogen at room temperature and pressure. (2) Low cost of liquefied storage and transportation. Ammonia can be stored and transported in liquid form by simply pressurizing it to 1.0MPa. A liquid ammonia tank truck can carry up to 30 tons of ammonia (about 5.29 tons of hydrogen), which is an order of magnitude higher than a long tube trailer (with a hydrogen capacity of less than 400kg). Therefore, the cost of transporting ammonia (about 0.001 yuan·kg-1·km-1) is also an order of magnitude lower than the cost of transporting hydrogen (0.02~0.10 yuan·kg-1·km-1). (3) Carbon-free energy storage. Ammonia's mature technical system, standard specifications, and low-cost synthesis, storage, and transportation can realize seasonal, long-distance, and "carbon-free" "ammonia-hydrogen" energy storage. (4) High safety. Ammonia's fire hazard is only Class B, and its explosion limit (16%~25%) is narrower than that of hydrogen (4%~76%), making it safer. Its pungent smell is a reliable alarm signal. Therefore, the development of ammonia as a hydrogen storage medium and the use of ammonia online decomposition hydrogen production and hydrogenation integrated stations are expected to solve the problem of traditional high-pressure hydrogen storage and transportation, so as to accelerate the promotion of green energy transformation and high-quality development. Summary of the invention

[0004] The main purpose of the present invention is to provide an integrated ammonia online hydrogen production and hydrogenation station to solve the problems of long-distance transportation, storage and filling of hydrogen. It is an amphibious public hydrogenation station suitable for filling cylinder containers, vehicles with different working pressures of 35MPa and 70MPa, and ships.

[0005] The present invention provides a comprehensive solution for an online ammonia hydrogen production and hydrogenation integrated station, including a power distribution preparation area, a hydrogen preparation area, and a hydrogen filling area, which are respectively located in three different areas divided by explosion-proof walls, and provide convenient management and safety protection in different areas.

[0006] The technical solution of the present invention is as follows: An ammonia online hydrogen production and hydrogenation integrated station is provided as follows Figure 1 As shown, the power distribution preparation area (1), hydrogen preparation area (2), and hydrogen filling area (3) are located in independent safety areas and are separated from each other by explosion-proof walls (4). The power distribution preparation area (1) includes conventional transformers, power distribution cabinets, water tanks, chillers, etc.; the hydrogen preparation area (2) includes an ammonia decomposition hydrogen production unit, a membrane separation extraction unit, and a hydrogen cache unit; the hydrogen filling area (3) includes three levels of compressor units, low, medium, and high, and corresponding filling units.

[0007] The process flow of an online ammonia hydrogen production and hydrogenation integrated station is as follows: Figure 2 As shown, there are multiple transmissions such as gas, liquid, heat, and communication between each unit module. The liquid ammonia storage tank (5) is used to receive liquid ammonia shipped from other places and store it safely. The liquid ammonia storage scale can be matched according to the actual local demand. 2, 3, 4... multiple tanks are designed. In order to avoid safety failures and alleviate the hydrogen pressure during peak hours, at least 2 liquid ammonia storage tanks are arranged, one for backup and one for use. As the hydrogen station continues to consume hydrogen, all low-pressure hydrogen storage tanks (14), medium-pressure hydrogen storage tanks (16), and high-pressure hydrogen storage tanks (18) will send the remaining hydrogen information in the tank to the station main controller, and send liquid ammonia delivery instructions according to the actual hydrogen demand. Liquid ammonia from different directions is collected by the three-way valve and released. Liquid ammonia is preheated and vaporized in three heat exchangers (6), (7), and (8) in turn, and then the ammonia enters the ammonia decomposition reaction tank (9) after passing through the one-way valve. Under the combined action of the catalyst and the high temperature of about 500°C, a decomposition reaction occurs.

[0008] The process flow of an online ammonia hydrogen production and hydrogenation integrated station is as follows: Figure 2As shown, the high-temperature nitrogen, hydrogen, and ammonia mixed gas from the ammonia decomposition reaction tank (9) is heat exchanged by the heat exchanger (7), and after the low-temperature raw ammonia is preheated to a certain temperature, the mixed gas continues to flow to the membrane separator (11) for separation and purification, and the purified high-purity hydrogen (99.99%-99.99999%) goes to the hydrogen buffer tank (12); the impurity gas (nitrogen, ammonia) intercepted by the membrane separator (11) returns to the bottom of the ammonia decomposition reaction tank (9) and combines with the fresh air from the air compressor (10) to burn and provide heat; when the combustion heat of the impurity gas is insufficient to support the heat demand of the decomposition reaction, a small portion of the high-purity hydrogen can be given through the three-way valve to merge with the impurity gas at the bottom of the ammonia decomposition reaction tank (9) for combustion and heat supply. At the same time, the high-temperature flue gas from the ammonia decomposition reaction tank (9) is heat exchanged by the heat exchanger (8), and the waste heat is further transferred to the raw ammonia, and then the flue gas enters the designated tail exhaust pipeline for safe discharge. Furthermore, the hot water after the cooling water passes through the rear low-pressure compressor unit (13), the medium-pressure compressor unit (15), and the high-pressure compressor unit (17) is collected in the heat exchanger (6) and used for the initial vaporization of liquid ammonia. Since the boiling point of liquid ammonia under standard atmospheric pressure is -33.4°C, the hot water makes it easier to vaporize the liquid ammonia and the waste heat can be more fully utilized.

[0009] The process flow of an online ammonia hydrogen production and hydrogenation integrated station is as follows: Figure 2 As shown, the purified high-purity hydrogen product is first collected in the hydrogen buffer tank (12), and then enters the low-pressure compressor unit (13) composed of two independent low-pressure compressors through a three-way valve. The compressors are used as a backup and the other is used to initially compress to about 25MPa level. Furthermore, 2, 3, 4... multiple independent machines can be set according to the scale and site configuration of the hydrogen refueling station, which can solve the failure crisis and improve the operation efficiency. The product hydrogen after initial compression is collected in the corresponding low-pressure hydrogen storage tank (14), part of which is used for filling the 20MPa-level hydrogen bottle container, which can be further sent to various places for sale and meet the hydrogen demand of laboratories; the hydrogen bottle container here can be set with 2, 3, 4... multiple container filling ports according to the scale and site configuration of the hydrogen refueling station to meet different demand scales. The other part of the hydrogen goes to the medium-pressure compressor unit (15).

[0010] The process flow of an online ammonia hydrogen production and hydrogenation integrated station is as follows: Figure 2As shown, the medium-pressure compressor unit (15) can also be boosted by 2, 3, 4... multiple independent medium-pressure compressors, and the pressure is increased to about 45MPa, and then collected in the corresponding medium-pressure hydrogen storage tank (16). Part of the medium-pressure hydrogen can be used to fill 35MPa-level cars, buses and even small ships through the medium-pressure hydrogenation gun (20). The other part of the medium-pressure hydrogen flows through the three-way valve to the high-pressure compressor unit (17) composed of two completely independent high-pressure compressors, and then is collected into the high-pressure hydrogen storage tank (18) again through the three-way valve. Part of the hydrogen in the high-pressure hydrogen storage tank (18) can be used to fill vehicles and ships that meet the 70MPa level through two high-pressure hydrogenation guns (21) controlled by switches. Similarly, the number of high-pressure compressors and high-pressure hydrogenation guns here can be set to 2, 3, 4... multiple according to the scale of the hydrogenation station and the site configuration to meet the hydrogenation needs of different scenarios. More importantly, the low-pressure, medium-pressure and high-pressure terminal hydrogen demand here is not limited to numerical specifications such as 25MPa, 35MPa and 70MPa, and can be customized to develop the pressure required for any actual working conditions.

[0011] Beneficial effects of the present invention

[0012] The hydrogen refueling station provided by the present invention adopts the technology of online decomposition of ammonia to produce hydrogen. The raw gas only needs to rely on the mature commercial network of liquid ammonia storage and transportation, and can obtain green ammonia sources from areas rich in green electricity resources such as green wind power and photovoltaic power, completely getting rid of the uneven distribution of natural resources and the problem of hydrogen transportation. This solution will make full use of the heat of the compressor cooling water to realize the vaporization of liquid ammonia, and at the same time use homemade hydrogen mixed with external air to burn to provide heat for the decomposition reaction of ammonia; the high-temperature product hydrogen and tail gas of the entire device can be preheated for the decomposition of ammonia through the heat exchanger, making full use of the waste heat of the reaction. The core unit of this solution is the ammonia decomposition hydrogen production reaction tank and membrane separator purification, which can be matched with compressors, buffer tanks, hydrogenation guns, etc., and can meet the conventional hydrogen needs of vehicles and ships at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0014] Figure 1 This is a reference diagram for the layout of the integrated ammonia online hydrogen production and hydrogenation station described in the present invention. Figure 2 This is the process flow chart of the ammonia online hydrogen production and hydrogenation integrated station of the present invention In the figure: (1) - power distribution preparation area; (2) - hydrogen preparation area; (3) - hydrogen filling area; (4) - explosion-proof wall; (5) - 2 liquid ammonia storage tanks; (6), (7) and (8) - 3 heat exchangers respectively; (9) - ammonia decomposition reaction tank; (10) - air compressor; (11) - membrane separator; (12) - hydrogen buffer tank; (13) - low-pressure compressor unit; (14) - low-pressure hydrogen storage tank; (15) - medium-pressure compressor unit; (16) - medium-pressure hydrogen storage tank; (17) - high-pressure compressor unit; (18) - high-pressure hydrogen storage tank; (19) - 2 hydrogen bottle containers; (20) - 2 medium-pressure hydrogen filling guns; (21) - 2 high-pressure hydrogen filling guns. DETAILED DESCRIPTION

[0015] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0016] The present invention provides an integrated ammonia online hydrogen production and hydrogenation station. The key point is that the hydrogenation station adopts an ammonia online decomposition hydrogen production mode, which replaces the high-cost and low-efficiency solution of long-distance hydrogen transportation. The hydrogen transportation capacity is improved by an order of magnitude, and the on-site production and use flexibility avoids the high risk of large-scale hydrogen storage, which plays a positive role in promoting the popularization and application of hydrogen energy.

[0017] The invention provides an integrated ammonia online hydrogen production and hydrogenation station. The key point is that the hydrogenation station adopts low-temperature ammonia online decomposition hydrogen production technology, which reduces the decomposition temperature from the conventional 800°C to 500°C, making a huge contribution to the efficient development and utilization of energy from a technical level.

[0018] The present invention provides an integrated ammonia online hydrogen production and hydrogenation station. The key point is that the hydrogenation station adopts membrane separation technology, which has great improvements in energy efficiency, product purity, equipment volume, weight and floor space compared with conventional pressure swing adsorption (PSA) technology, making the popularization of hydrogenation stations more flexible, tending to be refined and miniaturized, and plays a vital role in the application and promotion of hydrogen energy.

[0019] The invention provides an integrated ammonia online hydrogen production and hydrogenation station, the key point of which is as follows: Figure 2 The process design shown is: First, the ammonia decomposition reactor (9) is highly integrated with the hydrogen direct burner. From the perspective of energy conversion, this world-leading hydrogen direct combustion technology makes the heat transfer method more direct and efficient; Second, liquid ammonia comes out of the storage tank (5) and passes through three heat exchangers (6), (7), and (8) in sequence, which fully utilize the waste heat of the compressor, product gas, and flue gas, greatly improving the thermal efficiency of the entire station and achieving a major breakthrough in energy economy, making it more suitable for use in distributed hydrogen refueling stations. Third, the impure ammonia and high-purity hydrogen coming out of the membrane separator (11) can be diverted to the bottom of the ammonia decomposition reaction tank (9) for direct combustion, making full use of nearly 100% of the fuel and further reducing the operating cost of the hydrogen refueling station; Fourth, all three types of compressor units (13), (15) (17) of low, medium and high power use adopt the principle of one standby and one in use to prevent one unit from stopping operation due to failure, which is both safe and can meet customer needs and experience. At the same time, the number of compressors can be further increased according to the local hydrogen demand scale and site area, and they can operate independently to meet a wider market demand. Fifth, the compressed hydrogen is stored in hydrogen storage tanks (14) (16) (18) of three different pressure ranges: low, medium and high pressure, which can meet the common hydrogen demand in the market and cover hydrogen bottle containers, 35MPa and 70MPa hydrogen bottles at the same time, further expanding the customer base of hydrogen refueling stations; Sixth, thanks to the convenience of liquid ammonia transportation, hydrogen refueling stations can be set up in ports and other places as needed, which can not only meet the hydrogen refueling needs of land vehicles, but also solve the hydrogen use problem of hydrogen-powered ships. It is more conducive to the popularization and promotion of hydrogen refueling stations by both land and water.

Claims

1. An integrated ammonia online hydrogen production and hydrogenation station, characterized in that: It consists of three independent safety areas: a power distribution preparation area (1), a hydrogen preparation area (2), and a hydrogen filling area (3), which are separated from each other by explosion-proof walls (4).

2. The ammonia online hydrogen production and hydrogenation integrated station according to claim 1, characterized in that: The power distribution preparation area (1) includes a transformer, a power distribution cabinet, a water tank, and a chiller; the hydrogen production area (2) includes an ammonia decomposition hydrogen production unit, a membrane separation extraction unit, and a hydrogen buffer unit; the hydrogen filling area (3) includes three levels of compressor units of low, medium, and high levels and corresponding filling units; wherein gas, liquid, heat, and communication are transmitted between the units in the hydrogen production area (2).

3. The ammonia online hydrogen production and hydrogenation integrated station according to claim 1, characterized in that: The ammonia online hydrogen production and hydrogenation integrated station also includes a liquid ammonia storage tank (5) for receiving liquid ammonia shipped from other places and storing it safely. The liquid ammonia storage scale can be matched according to the actual local demand, and 2, 3, 4... multiple tanks can be designed. In order to avoid safety failures and alleviate the hydrogen pressure during peak hours, at least 2 liquid ammonia storage tanks are arranged, one for backup and the other for use.

4. The ammonia online hydrogen production and hydrogenation integrated station according to claim 1, characterized in that: Liquid ammonia is preheated and vaporized in three heat exchangers (6), (7), and (8) in sequence, and then enters the ammonia decomposition reaction tank (9) after passing through a one-way valve. Under the combined action of the catalyst and a high temperature of about 500°C, a decomposition reaction occurs. As the hydrogen station continues to consume hydrogen, all low-pressure hydrogen storage tanks (14), medium-pressure hydrogen storage tanks (16), and high-pressure hydrogen storage tanks (18) will send information on the remaining hydrogen in the tanks to the station main controller, and send liquid ammonia delivery instructions based on actual hydrogen demand. Liquid ammonia from different directions is collected by a three-way valve and released.

5. The ammonia online hydrogen production and hydrogenation integrated station according to claim 4, characterized in that: The high-temperature nitrogen, hydrogen and ammonia mixed gas from the ammonia decomposition reaction tank (9) is heat exchanged in the heat exchanger (7) to preheat the low-temperature raw ammonia to a certain temperature. The mixed gas then continues to flow to the membrane separator (11) for separation and purification. The purified high-purity hydrogen goes to the hydrogen buffer tank (12).

6. The ammonia online hydrogen production and hydrogenation integrated station according to claim 5, characterized in that: The impurity gases (nitrogen, ammonia) intercepted by the membrane separator (11) are returned to the bottom of the ammonia decomposition reaction tank (9) to combine with the fresh air from the air compressor (10) to burn and provide heat. When the combustion heat of the impurity gases is insufficient to support the heat demand of the decomposition reaction, a small portion of the high-purity hydrogen can be fed through a three-way valve to merge with the impurity gases at the bottom of the ammonia decomposition reaction tank (9) to burn and provide heat.

7. The integrated ammonia online hydrogen production and hydrogenation station according to claim 4, characterized in that: The high-temperature flue gas from the ammonia decomposition reaction tank (9) is heat exchanged in the heat exchanger (8), and the waste heat is transferred to the raw ammonia gas. The flue gas then enters the designated tail exhaust pipe for safe discharge. The hot water after the cooling water passes through the rear low-pressure compressor unit (13), the medium-pressure compressor unit (15), and the high-pressure compressor unit (17) is collected in the heat exchanger (6) and used for the initial vaporization of liquid ammonia. Since the boiling point of liquid ammonia under standard atmospheric pressure is -33.4°C, the hot water makes it easier to vaporize the liquid ammonia and the waste heat can be more fully utilized.

8. The ammonia online hydrogen production and hydrogenation integrated station according to claim 5, characterized in that: The purified high-purity hydrogen product is first collected in a hydrogen buffer tank (12), and then enters a low-pressure compressor unit (13) consisting of two independent low-pressure compressors through a three-way valve, with one compressor in standby and the other in use, and is initially compressed to a level of about 25 MPa.

9. The integrated ammonia online hydrogen production and hydrogenation station according to claim 8, characterized in that: The hydrogen product after the initial compression is collected in the corresponding low-pressure hydrogen storage tank (14). A part of it is used to fill the 20MPa-level hydrogen bottle container and can be further sent to various places for sale to meet the hydrogen needs of laboratories, etc.; the other part of the hydrogen goes to the medium-pressure compressor unit (15).

10. The ammonia online hydrogen production and hydrogenation integrated station according to claim 7, characterized in that: The medium-pressure compressor unit (15) can also be pressurized by 2, 3, 4... multiple independent medium-pressure compressors, and the pressure is increased to about 45MPa, and then collected in the corresponding medium-pressure hydrogen storage tank (16); part of the medium-pressure hydrogen can be used to fill 35MPa-level cars, buses and even small ships through a medium-pressure hydrogen filling gun (20); and the other part of the medium-pressure hydrogen flows through a three-way valve to a high-pressure compressor unit (17) composed of two completely independent high-pressure compressors, and then collected again through a three-way valve into a high-pressure hydrogen storage tank (18).

11. The integrated ammonia online hydrogen production and hydrogenation station according to claim 7, characterized in that: A portion of the hydrogen in the high-pressure hydrogen storage tank (18) can be respectively filled into vehicles and ships meeting the 70MPa level through two high-pressure hydrogen filling guns (21) controlled by switches.

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