Natural gas to hydrogen production unit

Abstract

This application provides a natural gas-to-hydrogen device, including a boiler, a steam buffer tank, a feed gas buffer tank, a desulfurization tank, and a preheater, a converter, a medium-term transformer, a PSA unit, and a hydrogen buffer tank connected in sequence. The steam buffer tank is connected to the boiler via a steam pipeline, on which a steam pressure regulating valve and a first manual valve are connected in parallel. The desulfurization tank is connected to the feed gas buffer tank and has a vent pipeline with a vent valve. The preheater is connected to both the desulfurization tank and the steam buffer tank via a mixing pipeline. A water-to-carbon ratio monitoring element is installed on the mixing pipeline and connected to the vent valve. In this application, the steam pressure can be controlled and regulated by the steam pressure regulating valve and the first manual valve, and the water-to-carbon ratio can be monitored and adjusted in real time by the water-to-carbon ratio monitoring element and the vent valve, thereby improving the safety of the device operation, extending the service life of the catalyst, and reducing operating costs.

Description

Technical Field

[0001] This application belongs to the field of hydrogen production technology, and more specifically, relates to a natural gas hydrogen production device. Background Technology

[0002] Currently, natural gas-to-hydrogen plants use natural gas as feedstock and employ steam reforming, intermediate-temperature shift conversion, and PSA gas separation technologies to produce pure hydrogen. The steam reforming control system is the most complex, including unit load and water / carbon ratio control, combustion control, and more. Most of these controls are complex, ensuring the steam reforming operates normally within the process requirements. The application of a highly sophisticated control system guarantees the safe and stable operation of the natural gas-to-hydrogen plant.

[0003] The desulfurized feed gas and the process-generated steam are mixed at a water-to-carbon ratio of H2O / ∑C = 3.5 and then preheated to 550°C in the mixed gas preheating coil. The mixture is then evenly fed into the conversion tube through the upper gas collecting main pipe and the upper pig tail pipe. In the catalyst bed, methane reacts with water vapor to produce CO, CO2 and H2.

[0004] The heat required for methane conversion is provided by the combustion of the mixed gas in the top burner. The temperature of the converted gas exiting the converter is about 700-850℃, and the residual methane content is about 3.0-4.0%. It enters the first tube pass of the waste heat boiler for heat exchange, which generates saturated steam at 2.1 MPa. The temperature of the converted gas drops to about 300℃ and enters the intermediate shift reactor through the pipeline to cause the CO to undergo a conversion reaction. The converted gas exiting the intermediate shift reactor enters the second tube pass of the waste heat boiler for heat exchange, which generates saturated steam at 2.1 MPa.

[0005] The conversion section employs advanced natural gas steam reforming technology. Under high inlet and outlet temperatures and high carbon space velocities, a steam reforming reaction occurs to produce hydrogen. The carbon monoxide content in the process gas exiting the reformer is approximately 13%. Since steam does not enter the reformer, natural gas enters the reforming pipe directly, causing a rapid drop in the water-to-carbon ratio. If the ratio falls below 2.7, there is a risk of carbon precipitation; if it falls below 2, it will certainly cause serious catalyst poisoning and carbon precipitation. Utility Model Content

[0006] The purpose of this application is to provide a natural gas hydrogen production device to solve the technical problem of abnormal water-to-carbon ratio in the prior art, which affects the safe operation of the device.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows: A natural gas hydrogen production device is provided, comprising a boiler, a steam buffer tank, a feed gas buffer tank, a desulfurization tank, a preheater, a converter, a medium-term converter, a PSA unit, and a hydrogen buffer tank; the boiler is used to generate steam; the steam buffer tank is connected to the boiler via a steam pipeline, and a steam pressure regulating valve and a first manual valve are connected in parallel on the steam pipeline; the feed gas buffer tank is used to store feed gas; the desulfurization tank is connected to the feed gas buffer tank; the desulfurization tank has a vent pipeline, and a vent valve is provided on the vent pipeline; the preheater is connected to the desulfurization tank and the steam buffer tank respectively via a mixing pipeline; a water-to-carbon ratio monitoring element is provided on the mixing pipeline, and the water-to-carbon ratio monitoring element is connected to the vent valve; the converter is connected to the preheater; the medium-term converter is used for carbon monoxide conversion; the PSA unit is connected to the medium-term converter and is used to purify hydrogen; the hydrogen buffer tank is connected to the PSA unit and is used to store hydrogen.

[0008] Furthermore, one end of the mixing pipeline has a first branch and a second branch; the first branch is connected to the steam buffer tank; and the second branch is connected to the desulfurization tank.

[0009] Furthermore, the first branch is equipped with a steam ratio regulating valve and a second manual valve; the steam ratio regulating valve and the second manual valve are connected in parallel.

[0010] Furthermore, the venting valve includes a manual venting valve and an automatic venting valve connected in series, and the automatic venting valve is electrically connected to the water-carbon ratio monitoring element.

[0011] Furthermore, the natural gas hydrogen production unit also includes a natural gas compressor, which is installed on the pipeline connecting the feed gas buffer tank and the desulfurization tank.

[0012] Furthermore, the natural gas hydrogen production unit also includes a natural gas buffer tank, which is installed on the pipeline connecting the natural gas compressor and the desulfurization tank.

[0013] Furthermore, the natural gas hydrogen production unit also includes a heat exchanger and a water cooler, which are connected in series on the pipeline connecting the intermediate transformer and the PSA unit.

[0014] Furthermore, the natural gas hydrogen production unit also includes a separator, which is installed on the pipeline connecting the water cooler and the PSA unit.

[0015] Furthermore, the PSA unit is equipped with an exhaust gas pipeline, which is connected to the converter.

[0016] Furthermore, the raw material gas buffer tank is equipped with a combustion pipeline, which is connected to the converter.

[0017] The beneficial effects of the natural gas hydrogen production unit provided in this application are as follows: Compared with the prior art, this application achieves automated control of the natural gas hydrogen production process through the cooperation of components such as the boiler, steam buffer tank, feed gas buffer tank, desulfurization tank, preheater, converter, intermediate transformer, PSA unit, and hydrogen buffer tank; the steam pressure can be controlled and regulated by setting a steam pressure regulating valve and a first manual valve; and the water-to-carbon ratio monitoring element and vent valve can monitor and adjust the water-to-carbon ratio in real time, preventing catalyst damage and carbon precipitation risks caused by a rapid drop in the water-to-carbon ratio, thereby improving the safety of unit operation, extending the service life of the catalyst, and reducing operating costs. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a natural gas hydrogen production device provided in an embodiment of this application.

[0020] The following are the labeling elements in the figure:

[0021] 1-Boiler; 2-Steam buffer tank; 3-Raw gas buffer tank; 4-Desulfurization tank; 5-Preheater; 6-Converter; 7-Intermediate converter; 8-PSA unit; 9-Hydrogen buffer tank; 10-Steam pressure regulating valve; 11-First manual valve; 12-Steam ratio regulating valve; 13-Second manual valve; 14-Manual vent valve; 15-Automatic vent valve; 16-Natural gas compressor; 17-Natural gas buffer tank; 18-Heat exchanger; 19-Water cooler; 20-Separator; 21-Tail gas buffer tank. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0024] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] Please see Figure 1 The natural gas hydrogen production apparatus provided in the embodiments of this application will now be described. The natural gas to hydrogen production unit includes a boiler 1, a steam buffer tank 2, a feed gas buffer tank 3, a desulfurization tank 4, a preheater 5, a converter 6, a medium-term converter 7, a PSA unit 8, and a hydrogen buffer tank 9. The boiler 1 generates steam. The steam buffer tank 2 is connected to the boiler 1 via a steam pipeline, on which a steam pressure regulating valve 10 and a first manual valve 11 are connected in parallel. The feed gas buffer tank 3 stores feed gas. The desulfurization tank 4 is connected to the feed gas buffer tank 3 and has a vent pipeline with a vent valve. The preheater 5 is connected to both the desulfurization tank 4 and the steam buffer tank 2 via a mixing pipeline. A water-to-carbon ratio monitoring element is installed on the mixing pipeline and connected to the vent valve. The converter 6 is connected to the preheater 5. The medium-term converter 7 is used for carbon monoxide conversion. The PSA unit 8 is connected to the medium-term converter 7 and is used to purify hydrogen. The hydrogen buffer tank 9 is connected to the PSA unit 8 and is used to store hydrogen.

[0027] Compared with the prior art, the natural gas hydrogen production device provided in this application embodiment achieves automated control of the natural gas hydrogen production process through the cooperation of components such as boiler 1, steam buffer tank 2, feed gas buffer tank 3, desulfurization tank 4, preheater 5, converter 6, intermediate transformer 7, PSA unit 8, and hydrogen buffer tank 9. The steam pressure can be controlled and regulated by setting a steam pressure regulating valve 10 and a first manual valve 11. The water-to-carbon ratio monitoring element and vent valve can monitor and adjust the water-to-carbon ratio in real time, preventing catalyst damage and carbon deposition risks caused by a rapid drop in the water-to-carbon ratio. This improves the safety of device operation, extends catalyst lifespan, and reduces operating costs.

[0028] As is understandable, PSA stands for Pressure Swing Adsorption. It is a technology that separates and purifies gases based on the differences in the adsorption capacity of solid adsorbents for different components in a gas mixture. In a natural gas to hydrogen production plant, PSA unit 8 is used to purify hydrogen. By periodically changing operating conditions (such as pressure), the adsorbent switches between adsorption and desorption, thereby achieving the separation and purification of hydrogen.

[0029] In this embodiment, multiple desulfurization tanks 4 can be configured, connected in parallel. This parallel configuration improves desulfurization efficiency, ensuring that sulfides in the feed gas are fully removed and preventing their impact on subsequent hydrogen production. Furthermore, the parallel configuration allows for staggered maintenance of the desulfurization tanks 4, guaranteeing the continuous and stable operation of the natural gas-to-hydrogen unit.

[0030] In one embodiment of this application, one end of the mixing pipeline has a first branch and a second branch; the first branch is connected to the steam buffer tank 2; and the second branch is connected to the desulfurization tank 4.

[0031] In this embodiment, the mixing pipeline is designed with two branches: one branch connects to the steam buffer tank 2, and the other branch connects to the desulfurization tank 4. This design allows for effective mixing of the steam and the desulfurized feed gas before they enter the preheater 5. This ensures that the steam and feed gas are mixed according to the set water-to-carbon ratio, thereby improving reaction efficiency and reducing unnecessary side reactions.

[0032] Compared to existing technologies, the design of this application, by setting up two independent branches, allows for more flexible and precise mixing of steam and feed gas. This effectively controls the water-to-carbon ratio, avoiding reaction instability caused by fluctuations in steam or feed gas flow rates. Furthermore, by precisely controlling the mixing ratio of steam and feed gas, the efficiency of natural gas-to-hydrogen production can be improved, energy consumption reduced, and catalyst lifespan extended.

[0033] In one embodiment of this application, please refer to Figure 1 The first branch is equipped with a steam ratio regulating valve 12 and a second manual valve 13; the steam ratio regulating valve 12 and the second manual valve 13 are connected in parallel.

[0034] In this embodiment, the steam ratio regulating valve 12 automatically adjusts the steam flow rate entering the mixing pipeline according to the preset water-to-carbon ratio to ensure that the ratio of steam to raw material gas is always maintained at the optimal state. The second manual valve 13 serves as a backup or adjustment method; when the steam ratio regulating valve 12 malfunctions or requires manual intervention, the operator can adjust the steam flow rate by adjusting the second manual valve 13. This parallel configuration design improves the reliability and flexibility of the device, allowing the operator to flexibly adjust the steam flow rate according to actual conditions to meet different production needs.

[0035] In one embodiment of this application, please refer to Figure 1 The vent valve includes a manual vent valve 14 and an automatic vent valve 15 connected in series. The automatic vent valve 15 is electrically connected to the water-carbon ratio monitoring element.

[0036] In this embodiment, by adding an electrical connection between the automatic vent valve 15 and the water-to-carbon ratio monitoring element, real-time monitoring and automatic adjustment of the water-to-carbon ratio are achieved, avoiding equipment damage and catalyst poisoning caused by abnormal water-to-carbon ratios. This improves the operational safety and stability of the natural gas-to-hydrogen unit, and reduces maintenance costs and downtime.

[0037] In this embodiment, when the water-to-carbon ratio monitoring element detects that the water-to-carbon ratio in the mixing pipeline exceeds the preset range, it automatically sends a signal to the automatic vent valve 15, triggering its opening to release some of the raw material gas and quickly restore the water-to-carbon ratio to the normal range. The manual vent valve 14 provides additional safety and operational flexibility, allowing operators to directly control the venting process in emergencies or when manual adjustments are required. This dual control mechanism ensures the safety and stability of the natural gas-to-hydrogen unit during operation, further improving overall production efficiency and product quality.

[0038] In one embodiment of this application, please refer to Figure 1 The natural gas hydrogen production unit also includes a natural gas compressor 16, which is installed on the pipeline connecting the raw material gas buffer tank 3 and the desulfurization tank 4.

[0039] In this embodiment, by adding a natural gas compressor 16 between the raw gas buffer tank 3 and the desulfurization tank 4, the problem of insufficient pressure of natural gas before entering the desulfurization tank 4 is solved, ensuring the efficient operation of the desulfurization process. At the same time, this improvement can also enhance the operating efficiency and safety of the entire natural gas-to-hydrogen unit, reducing the risk of process fluctuations and equipment damage caused by insufficient natural gas pressure.

[0040] Specifically, the natural gas compressor 16 is used to extract feed gas from the feed gas buffer tank 3 and pressurize it before delivering it to the desulfurization tank 4 for desulfurization treatment. By installing the natural gas compressor 16, a stable and continuous supply of feed gas to the desulfurization tank 4 can be ensured, avoiding production interruptions or efficiency reductions caused by insufficient feed gas supply or pressure fluctuations. Furthermore, the use of the natural gas compressor 16 can improve the utilization rate of feed gas, reduce energy waste, and lower production costs. In addition, the natural gas compressor 16 has advantages such as simple structure, reliable operation, and convenient maintenance, and can adapt to natural gas-to-hydrogen units of different scales and process requirements.

[0041] In this embodiment, multiple natural gas compressors 16 can be configured, with multiple natural gas compressors 16 connected in parallel. The parallel configuration of multiple natural gas compressors 16 can further improve the compression efficiency and stability of the feed gas, ensuring the efficient and continuous operation of the natural gas-to-hydrogen unit. Simultaneously, the parallel configuration of the natural gas compressors 16 allows for staggered maintenance and repair, avoiding production interruptions caused by the failure of a single compressor, thus improving the reliability and stability of the entire unit.

[0042] In one embodiment of this application, please refer to Figure 1 The natural gas hydrogen production unit also includes a natural gas buffer tank 17, which is installed on the pipeline connecting the natural gas compressor 16 and the desulfurization tank 4.

[0043] In this embodiment, the natural gas buffer tank 17 further stabilizes the natural gas pressure. After the natural gas is output from the compressor, it first enters the natural gas buffer tank 17 for buffering and stabilization before being delivered to the desulfurization tank 4. This effectively reduces the impact of natural gas pressure fluctuations on the desulfurization process, improving desulfurization efficiency and stability. Simultaneously, the natural gas buffer tank 17 can also serve as a backup gas source in emergencies, ensuring the continuous operation of the natural gas hydrogen production unit under unforeseen circumstances. This design further enhances the reliability and stability of the natural gas hydrogen production unit, improving overall production efficiency and safety.

[0044] In one embodiment of this application, please refer to Figure 1 The natural gas to hydrogen production unit also includes a heat exchanger 18 and a water cooler 19, which are connected in series on the pipeline connecting the intermediate transformer 7 and the PSA unit 8.

[0045] In this embodiment, heat exchanger 18 is used to cool the high-temperature gas exiting the intermediate converter 7 and recover its heat, thereby improving the energy efficiency of the entire device. Water cooler 19 further cools the gas after heat exchange to a suitable temperature range for the operation of PSA unit 8, ensuring that PSA unit 8 can operate efficiently and stably. By connecting heat exchanger 18 and water cooler 19 in series, not only can the temperature of the gas entering PSA unit 8 be effectively controlled, improving the separation efficiency and hydrogen purity of PSA unit 8, but also the waste heat generated during the reaction process can be fully utilized to achieve energy recycling and reduce the energy consumption and operating costs of the device. This design reflects the innovation and practicality of this application in natural gas to hydrogen production technology and helps to promote the further development and application of natural gas to hydrogen production technology.

[0046] In one embodiment of this application, please refer to Figure 1 The natural gas to hydrogen production unit also includes a separator 20, which is installed on the pipeline connecting the water cooler 19 and the PSA unit 8.

[0047] In this embodiment, the main function of separator 20 is to perform gas-liquid separation on the gas cooled by water cooler 19, removing any liquid moisture and impurities that may be present. This ensures that the gas entering PSA unit 8 is dry and pure, preventing moisture and impurities from adversely affecting the separation effect and hydrogen purity of PSA unit 8. By adding separator 20, this application further improves the overall performance and product quality of the natural gas to hydrogen production unit, ensuring stable and efficient hydrogen production. At the same time, the installation of separator 20 also facilitates subsequent maintenance and operation, reducing maintenance costs and downtime.

[0048] In one embodiment of this application, please refer to Figure 1 The PSA unit 8 is equipped with a tail gas pipeline, which is connected to the converter 6.

[0049] In this embodiment, the tail gas pipeline effectively utilizes the exhaust gas emitted from PSA unit 8. After hydrogen purification is completed in PSA unit 8, the remaining tail gas is transported back to the converter 6 via the tail gas pipeline for combustion as fuel, thus achieving energy recycling. This design not only improves energy utilization efficiency and reduces the energy consumption and operating costs of the device, but also helps reduce environmental pollution, reflecting the environmental protection concept and innovative spirit of this application in natural gas hydrogen production technology. Through the connection of the tail gas pipeline, this application further optimizes the overall structure of the natural gas hydrogen production device, improving its economic efficiency and environmental friendliness.

[0050] In one embodiment of this application, please refer to Figure 1 The natural gas to hydrogen production unit also includes a tail gas buffer tank 21, which is installed on the pipeline connecting the PSA unit 8 and the converter 6.

[0051] The tail gas buffer tank 21 serves to buffer and stabilize the tail gas emitted from the PSA unit 8. Before being sent back to the reformer 6, the tail gas enters the tail gas buffer tank 21 for temporary storage and regulation to ensure stable flow and pressure, thus avoiding adverse effects on the combustion process in the reformer 6. By adding the tail gas buffer tank 21, this embodiment further improves the energy efficiency and operational stability of the natural gas to hydrogen production unit, while also helping to extend the service life of the reformer 6 and reduce maintenance costs and downtime. This design reflects the meticulous consideration and practicality of this application in the natural gas to hydrogen production process, and contributes to promoting the continuous development and application of natural gas to hydrogen technology.

[0052] In one embodiment of this application, please refer to Figure 1 The raw material gas buffer tank 3 is equipped with a combustion pipeline, which is connected to the converter 6.

[0053] In this embodiment, the combustion pipeline provides an effective way to handle the remaining feed gas in the feed gas buffer tank 3. During the natural gas to hydrogen production process, a certain amount of residual feed gas may accumulate in the feed gas buffer tank 3. By setting up the combustion pipeline, this residual feed gas can be safely and efficiently transported to the reformer 6 for combustion, thereby converting it into heat energy or using it in other processes. This design not only avoids waste of feed gas but also improves the overall energy efficiency of the unit. Simultaneously, the combustion pipeline also enhances the operational flexibility and adaptability of the natural gas to hydrogen production unit, enabling it to better cope with changes in different process conditions and production demands. Through the connection of the combustion pipeline, this application further improves the overall performance and operating efficiency of the natural gas to hydrogen production unit, contributing to a more efficient and environmentally friendly natural gas to hydrogen production process.

[0054] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A hydrogen production plant from natural gas, characterized in that, include: Boiler, the boiler being used to generate steam; A steam buffer tank is connected to the boiler via a steam pipeline, and a steam pressure regulating valve and a first manual valve are connected in parallel on the steam pipeline. A raw material gas buffer tank, wherein the raw material gas buffer tank is used to store raw material gas; A desulfurization tank is connected to the raw gas buffer tank; the desulfurization tank has a venting pipeline and a venting valve is provided on the venting pipeline; A preheater is connected to the desulfurization tank and the steam buffer tank respectively via a mixing pipeline; a water-to-carbon ratio monitoring element is installed on the mixing pipeline, and the water-to-carbon ratio monitoring element is connected to the vent valve; A converter, which is connected to the preheater; A converter for carbon monoxide conversion; The PSA unit is connected to the intermediate converter and is used to purify hydrogen. A hydrogen buffer tank is connected to the PSA unit; the hydrogen buffer tank is used to store hydrogen.

2. The hydrogen production plant from natural gas according to claim 1, characterized in that, One end of the mixing pipeline has a first branch and a second branch; the first branch is connected to the steam buffer tank; and the second branch is connected to the desulfurization tank.

3. The hydrogen production plant from natural gas according to claim 2, characterized in that, The first branch is equipped with a steam ratio regulating valve and a second manual valve; the steam ratio regulating valve and the second manual valve are connected in parallel.

4. The hydrogen production plant from natural gas according to claim 1, characterized in that, The venting valve includes a manual venting valve and an automatic venting valve connected in series, and the automatic venting valve is electrically connected to the water-carbon ratio monitoring element.

5. The hydrogen generation plant from natural gas according to claim 1, characterized in that, The natural gas hydrogen production unit also includes a natural gas compressor, which is installed on the pipeline connecting the feed gas buffer tank and the desulfurization tank.

6. The hydrogen generation plant from natural gas according to claim 5, characterized in that, The natural gas hydrogen production unit also includes a natural gas buffer tank, which is installed on the pipeline connecting the natural gas compressor and the desulfurization tank.

7. The hydrogen production plant from natural gas according to claim 1, characterized in that, The natural gas hydrogen production unit also includes a heat exchanger and a water cooler, which are connected in series on the pipeline connecting the intermediate transformer and the PSA unit.

8. The hydrogen production plant from natural gas according to claim 7, characterized in that, The natural gas hydrogen production unit also includes a separator, which is installed on the pipeline connecting the water cooler and the PSA unit.

9. The hydrogen production plant from natural gas according to claim 1, characterized in that, The PSA unit is equipped with an exhaust gas pipeline, which is connected to the converter.

10. The hydrogen production plant from natural gas according to any of claims 1 to 9, characterized in that, The raw material gas buffer tank is equipped with a combustion pipeline, which is connected to the converter.

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