Method for the storage and delivery of hydrogen gas using low pressure

Abstract

This invention discloses a method for low-pressure storage and mixing of hydrogen, relating to the field of hydrogen energy utilization technology. The invention designs a novel low-pressure hydrogen storage tank with an internal piston chamber structure. The piston moves vertically along the inner wall of the tank. Below the piston is the hydrogen storage chamber, with an inlet and outlet pipe connected to its lower outer end. A counterweight is placed above the piston depending on the operating condition. Hydrogen is produced using an atmospheric pressure hydrogen production device. The produced hydrogen is separated, purified, and connected to the inlet pipe of the hydrogen storage chamber. The outlet pipe of the hydrogen storage chamber is divided into two lines, connecting to a medium-pressure mixing pipeline and a low-pressure mixing pipeline respectively. A compressor is connected to the medium-pressure mixing pipeline, and its outlet is connected to the inlet of the medium-pressure mixing pipeline. The outlet of the low-pressure mixing pipeline is connected to the inlet of the low-pressure mixing pipeline. This invention eliminates the need for constructing a dedicated hydrogen delivery pipeline, resulting in low cost and good safety.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy utilization technology, specifically a method for low-pressure storage and blending of hydrogen for transportation. Background Technology

[0002] Hydrogen energy is an ideal clean energy source with enormous development potential. Convenient and efficient storage and transportation of hydrogen is a pressing issue. Based on the different forms of hydrogen, current main hydrogen storage technologies include solid-state hydrogen storage, cryogenic liquid hydrogen storage, high-pressure gaseous hydrogen storage, and organic liquid hydrogen storage, each with its own characteristics and applicable scope. Among these, high-pressure gaseous hydrogen storage is currently the most widely used technology. However, widely used metallic materials, especially high-strength materials used in the manufacture of high-pressure containers, are susceptible to hydrogen embrittlement when in prolonged contact with hydrogen. This manifests as a significant reduction in strength and plasticity, as well as hydrogen-induced hysteresis fracture under low stress, generally referred to as hydrogen embrittlement or hydrogen damage. To date, there is still no good solution to hydrogen embrittlement. The risk of hydrogen embrittlement can lead to the failure of hydrogen storage tanks, and coupled with the flammable and explosive properties of hydrogen, it can easily cause fires, explosions, or even major disasters. Therefore, hydrogen storage, especially high-pressure hydrogen storage, places high demands on storage tank conditions.

[0003] Because constructing new hydrogen pipelines requires significant costs and time, many countries have begun researching and experimenting with hydrogen-blended natural gas using existing natural gas pipelines. Existing technologies in this area are also increasing. For example, patent CN113090946B, entitled "A Clamshell Pipe Structure for Promoting Mixing of Natural Gas and Hydrogen in a Hydrogen-Blended Natural Gas Pipeline," discloses adding a clamshell-shaped bulge structure within the original cylindrical pipe structure to disrupt the incoming flow, creating vortices or turbulence for better mixing. However, this is only one mixing method. Another example is patent CN110095359B, entitled "A Material Fatigue Damage Test Method under High-Pressure Hydrogen-Blended Natural Gas Environment," which discloses a method using a loading shaft to push a steel ball to apply load to a disc-shaped thin-sheet sample, avoiding complex servo testing mechanisms. However, this is also an experiment on high-pressure hydrogen, and it does not effectively address the risks of hydrogen embrittlement leading to tank lifespan issues and the resulting safety problems. Therefore, a method for low-pressure storage and blended transportation of hydrogen is urgently needed to solve this problem. Summary of the Invention

[0004] The purpose of this invention is to provide a method for low-pressure storage and mixed transportation of hydrogen, in order to solve the problems that hydrogen embrittlement can easily lead to danger under high pressure, making it difficult to store and transport, and that building new hydrogen pipelines is time-consuming and expensive.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for low-pressure storage and mixing and transportation of hydrogen, comprising the following specific contents:

[0006] A novel low-pressure hydrogen storage tank is designed with an internal piston chamber structure. The piston moves vertically along the inner wall of the low-pressure hydrogen storage tank. The hydrogen storage chamber is located below the piston, and an inlet pipe and an outlet pipe are connected to its lower outer end. A counterweight is placed above the piston according to the working condition.

[0007] Hydrogen is produced using an atmospheric pressure hydrogen production device. The produced hydrogen is separated, purified, and then connected to the inlet pipe of the hydrogen storage chamber.

[0008] The outlet pipe of the hydrogen storage chamber is divided into two lines, which are connected to the medium-pressure mixing pipeline and the low-pressure mixing pipeline respectively. The medium-pressure mixing pipeline is connected to a compressor, and its outlet end is connected to the inlet of the medium-pressure mixing pipeline; the outlet end of the low-pressure mixing pipeline is connected to the inlet of the low-pressure mixing pipeline.

[0009] The medium-pressure mixed gas pipeline has two inlets, with the other one connected to the gas supply pipeline of the medium-pressure natural gas network; the low-pressure mixed gas pipeline has two inlets, with the other one connected to the gas supply pipeline of the low-pressure coke oven gas network.

[0010] Preferably, in the atmospheric pressure hydrogen production device, no counterweight is placed on the upper end of the piston during the process of hydrogen entering the hydrogen storage chamber; during the process of hydrogen being discharged from the storage chamber to the outlet pipe, a counterweight is placed on the upper end of the piston, and pressure is applied to the hydrogen in the hydrogen storage chamber through the piston.

[0011] Preferably, regulating valves, safety valves, temperature measuring points, and pressure measuring points are respectively installed on the medium-pressure mixing pipeline and the gas supply pipeline of the medium-pressure natural gas pipeline network.

[0012] Preferably, regulating valves, safety valves, temperature measuring points, and pressure measuring points are respectively installed on the gas inlet pipelines of the low-pressure mixing pipeline and the low-pressure coke oven gas pipeline network.

[0013] Preferably, the atmospheric pressure hydrogenation unit uses an atmospheric pressure electrolyzer.

[0014] Preferably, the inlet and outlet pipes of the low-pressure hydrogen storage tank are equipped with check valves.

[0015] Preferably, the low-pressure hydrogen storage tank (2) has a diameter not exceeding 60m, a height not exceeding 100m, and a nominal volume not exceeding 300,000m³. 3 .

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. The hydrogen is stored and transported using a low-pressure method, which allows the existing coke oven gas and natural gas pipelines to be used to transport hydrogen to users without the need to build new hydrogen transport pipelines, thus reducing costs.

[0018] 2. This hydrogen uses a low-pressure storage and mixing method for transportation. A new low-pressure hydrogen storage tank was designed to meet the special requirements of hydrogen. It uses a movable internal piston to adapt to the storage and transportation of hydrogen. The pressure in the piston chamber is usually close to the external atmospheric pressure. Compared with the existing high-pressure systems, the hydrogen leakage rate is significantly reduced, resulting in better safety. In addition, due to the use of low-pressure storage, the lifespan of the storage tank material is also significantly longer than that of high-pressure and medium-pressure containers, which helps to reduce equipment maintenance and replacement costs during the use of hydrogen energy. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the low-pressure storage and mixing conveying system of the present invention.

[0020] In the diagram: 1. Atmospheric pressure hydrogen unit; 2. Low-pressure hydrogen storage tank; 3. Medium-pressure mixing pipeline; 4. Low-pressure mixing pipeline. Detailed Implementation

[0021] A method for low-pressure storage and mixed transportation of hydrogen includes the following specific aspects:

[0022] A novel low-pressure hydrogen storage tank 2 is designed, with an internal piston chamber structure. The piston moves vertically along the inner wall of the low-pressure hydrogen storage tank 2. The lower part of the piston is the hydrogen storage chamber, and the lower end of the outer side is connected to the inlet pipe and the outlet pipe. A counterweight is placed on the upper part of the piston according to the working state. For reference, a concrete counterweight can be suspended from the upper opening of the low-pressure hydrogen storage tank 2 and placed on the upper part of the piston.

[0023] Hydrogen is produced using an atmospheric pressure hydrogen production device 1. The produced hydrogen is separated, purified, and then connected to the inlet pipe of the hydrogen storage chamber.

[0024] The outlet pipe of the hydrogen storage chamber is divided into two lines, which are connected to the medium-pressure mixing line 3 and the low-pressure mixing line 4 respectively. The medium-pressure mixing line 3 is connected to a compressor, and its outlet end is connected to the inlet of the medium-pressure mixed gas line; the outlet end of the low-pressure mixing line 4 is connected to the inlet of the low-pressure mixed gas line.

[0025] The medium-pressure mixed gas pipeline has two inlets, with the other one connected to the gas supply pipeline of the medium-pressure natural gas pipeline network; the low-pressure mixed gas pipeline has two inlets, with the other one connected to the gas supply pipeline of the low-pressure coke oven gas pipeline network; based on the above method, hydrogen can be transported using existing coke oven gas and natural gas pipelines.

[0026] The placement of a counterweight above the piston, depending on the working state, is provided for reference. When the atmospheric pressure hydrogen device 1 is producing hydrogen and hydrogen is entering the hydrogen storage chamber, no counterweight is placed on the top of the piston. When hydrogen is being discharged from the storage chamber to the outlet pipe, a counterweight is placed on the top of the piston to pressurize the hydrogen in the hydrogen storage chamber. Of course, other working states are also possible depending on the work requirements. In addition, check valves or one-way valves can be installed on the inlet and outlet pipes of the low-pressure hydrogen storage tank 2 to ensure that hydrogen does not flow back.

[0027] In a preferred embodiment, the medium-pressure mixing pipeline 3 and the gas supply pipeline of the medium-pressure natural gas network are respectively equipped with relevant valve groups and safety instruments, such as regulating valves, safety valves, temperature measuring points and pressure measuring points.

[0028] In a preferred embodiment, the low-pressure mixing pipeline 4 and the gas supply pipeline of the low-pressure coke oven gas network are respectively equipped with relevant valve groups and safety instruments, such as regulating valves, safety valves, temperature measuring points and pressure measuring points.

[0029] Furthermore, the atmospheric pressure hydrogenation unit 1 can be further preferably made of an atmospheric pressure electrolyzer, which has a simpler manufacturing process, is easier to scale up, does not require pressure resistance in the design, has low strength requirements for end plates, frames, etc., saves material input, does not require pressure regulating devices, and does not have the problem of leakage of pressure valves. The hydrogen gas coming out of the atmospheric pressure electrolyzer can also undergo general separation and purification treatment.

[0030] In addition to the specific storage and mixing methods described above, this invention also describes a novel low-pressure hydrogen storage tank 2. For reference, the diameter of the low-pressure hydrogen storage tank 2 can be set to no more than 60m, the height can be set to no more than 100m, and the nominal volume can reach 300,000m³. 3 It can play a role in storing, buffering and stabilizing the pressure of the entire hydrogen system.

[0031] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

[0032] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A method for hydrogen storage and delivery using low pressure storage and blending, characterized in that, The application relates to a new low-pressure hydrogen storage tank (2) which is internally provided with a piston chamber structure, the moving direction of the piston is in the vertical direction along the inner wall of the low-pressure hydrogen storage tank (2), the lower part of the piston is provided with a hydrogen storage chamber, the lower end of the outer side of the hydrogen storage chamber is connected with an air inlet pipe and an air outlet pipe, the upper part of the piston is provided with a counterweight according to the working state; hydrogen is prepared by using a normal-pressure hydrogen preparation device (1), the prepared hydrogen is separated and purified and then connected to the air inlet pipe of the hydrogen storage chamber; the air outlet pipe of the hydrogen storage chamber is divided into two paths and connected with a medium-pressure mixing pipe (3) and a low-pressure mixing pipe (4), the medium-pressure mixing pipe (3) is connected with a pressurizing machine, and the pipe outlet end of the medium-pressure mixing pipe (3) is connected with the air inlet of a medium-pressure mixed gas pipe; the outlet end of the low-pressure mixing pipe (4) is connected with the air inlet of a low-pressure mixed gas pipe; the air inlets of the medium-pressure mixed gas pipe and the low-pressure mixed gas pipe are respectively provided with two air inlet pipes, one of which is connected with a medium-pressure natural gas pipe network, and the other of which is connected with a low-pressure coke oven gas pipe network. The normal-pressure hydrogen preparation device (1) is used for preparing hydrogen, the upper end of the piston is not provided with a counterweight during the process that the hydrogen enters the hydrogen storage chamber, the upper end of the piston is provided with a counterweight during the process that the hydrogen is discharged from the hydrogen storage chamber to the air outlet pipe, and the hydrogen in the hydrogen storage chamber is pressurized by the piston. The medium-pressure mixing pipe (3) and the air inlet pipe of the medium-pressure natural gas pipe network are respectively provided with adjusting valves, safety valves, temperature measuring points and pressure measuring points. The low-pressure mixing pipe (4) and the air inlet pipe of the low-pressure coke oven gas pipe network are respectively provided with adjusting valves, safety valves, temperature measuring points and pressure measuring points. The normal-pressure hydrogen preparation device (1) is a normal-pressure electrolytic cell.

2. The method of claim 1, wherein: The air inlet pipe and the air outlet pipe of the low-pressure hydrogen storage tank (2) are respectively provided with check valves.

3. The method of claim 1, wherein: ​ 4. The method of claim 1, wherein: ​ 5. The method of claim 1, wherein: ​ 6. The method of claim 1, wherein: ​ 7. The method of claim 1, wherein: The low-pressure hydrogen storage tank (2) has a diameter of not more than 60 m, a height of not more than 100 m, and a nominal volume of not more than 300,000 m 3 .

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