A two-stage fuel cell-grade hydrogen purification method and system

Abstract

This disclosure relates to a two-stage purification method and system for fuel cell-grade hydrogen. The method involves first passing high-purity hydrogen feedstock purified from a PSA unit through a desulfurization unit to adsorb trace amounts of sulfides (such as hydrogen sulfide and carbonyl sulfide), and then introducing the desulfurized hydrogen into a decarbonization unit to adsorb trace amounts of carbon monoxide. This achieves effective removal of trace sulfides and carbon monoxide from the high-purity hydrogen. During operation, this method effectively adsorbs sulfides and carbon monoxide without requiring continuous pressure swing cycle adsorption. It offers a longer single adsorption cycle, more convenient operation, and easier start-up and shutdown. This method improves hydrogen purity and ensures hydrogen yield while simultaneously producing hydrogen for fuel cells.

Description

Technical Field

[0001] This disclosure relates to the field of hydrogen fuel cells, and more specifically, to a two-stage fuel cell stage hydrogen purification method and system. Background Technology

[0002] The supply of hydrogen is a crucial factor affecting the industrialization of hydrogen energy and fuel cells. my country is the world's largest producer of industrial hydrogen, primarily from coal, natural gas, and industrial by-products. Industrial hydrogen standards differ from fuel cell standards. The newly promulgated GB / T37244-2018 standard, "Proton Exchange Membrane Fuel for Fuel Cell Vehicles - Hydrogen," specifies clear requirements for hydrogen. While the purity requirement for fuel cell-grade hydrogen is no longer stringent (>99.97%), the requirements for trace impurities such as CO and H2S are extremely strict. Hydrogen production from fossil fuels is the primary method for obtaining industrial hydrogen in the petrochemical industry. This process inevitably produces impurities such as hydrogen sulfide and carbon monoxide, which severely deactivate platinum electrode catalysts. The GB / T37244-2018 standard requires hydrogen sulfide concentrations to be <4 ppb and carbon monoxide concentrations to be <200 ppb.

[0003] Pressure Swing Adsorption (PSA) technology is one of the most important technologies for hydrogen purification. The PSA process relies on the principle of adsorption under high pressure and desorption under low pressure by an adsorbent (common adsorbents include molecular sieves, activated carbon, silica gel, activated alumina, etc.) and the components to be separated, achieving separation through repeated cycles of adsorption and desorption. Although PSA can achieve hydrogen purity of 99.9% or higher, it cannot guarantee a CO concentration <0.2ppm, let alone a sulfur compound concentration <4ppb. Furthermore, PSA operation suffers from high energy consumption, large footprint and investment, low hydrogen yield, and uneconomical retrofitting of existing PSA units. CN110682803A discloses a hydrogen quality assurance system for fuel cell vehicles. This patent involves two adsorbers and a reactor for removing hydrogen. The adsorbents in the adsorbers are mainly conventional activated carbon and molecular sieves. During operation, pressure swing adsorption cycles occur in the two reactors, with the adsorption pressure controlled between 10-30MPa. Regarding carbon monoxide adsorbents, common types include molecular sieves, activated carbon, and cuprous-based adsorbents. Their adsorption capacity and removal depth perform better under lower temperature conditions (e.g., room temperature). There are many types of desulfurizing agents; common metal oxide desulfurizing agents include zinc oxide, iron oxide, copper oxide, calcium oxide, and manganese oxide. Conventional oxide desulfurizing agents have disadvantages such as low sulfur capacity and high desulfurization reaction temperature (reaching 200-300℃).

[0004] Current technology cannot yet achieve efficient removal of trace sulfides and carbon monoxide from hydrogen simultaneously through simple process methods. Summary of the Invention

[0005] The purpose of this disclosure is to provide a two-stage fuel cell-grade hydrogen purification method and system. This method achieves efficient removal of trace sulfides and carbon monoxide from hydrogen feedstock from PSA units, with a simpler process and higher efficiency.

[0006] To achieve the above objectives, the first aspect of this disclosure provides a method for deep removal of trace amounts of carbon monoxide from hydrogen gas, comprising the following steps:

[0007] S1. The hydrogen feedstock from the PSA unit is introduced into one of the two desulfurization adsorption devices in the desulfurization unit, where it comes into contact with the desulfurization adsorbent to adsorb sulfides and obtain desulfurized hydrogen.

[0008] Then, the desulfurized hydrogen from the desulfurization unit is introduced into one of the two decarbonization adsorption devices in the decarbonization unit, where it comes into contact with the decarbonization adsorbent to adsorb carbon monoxide and obtain product hydrogen.

[0009] Monitor the concentrations of sulfide (C1) and carbon monoxide (C2) in the hydrogen gas exiting the decarbonization unit.

[0010] S2, When C1 reaches the first concentration threshold C 01 When the hydrogen feedstock is stopped from being introduced into the desulfurization adsorption unit in the desulfurization unit, the hydrogen feedstock is introduced into the other of the two desulfurization adsorption units in the desulfurization unit to contact the desulfurization adsorbent for sulfide adsorption; and the desulfurization adsorbent in the desulfurization adsorption unit that has stopped operating is regenerated and desorbed, or the desulfurization adsorbent in the desulfurization adsorption unit that has stopped operating is replaced with fresh desulfurization adsorbent; and

[0011] When C2 reaches the second concentration threshold C 02 When the desulfurized hydrogen is introduced into the decarbonization adsorption device in the decarbonization unit, the desulfurized hydrogen is introduced into the other of the two decarbonization adsorption devices in the decarbonization unit to adsorb carbon monoxide and obtain product hydrogen; and the decarbonization adsorbent in the decarbonization adsorption device that has stopped working is regenerated and desorbed.

[0012] S3, Repeat steps S1 to S2; where C 01 The concentration was 0.003–0.004 ppm, C 02 The concentration is 0.18–0.20 ppm.

[0013] Optionally, the desulfurization unit includes a first desulfurization adsorption device and a second desulfurization adsorption device arranged in parallel. The method further includes: S201, introducing hydrogen feedstock into the first desulfurization adsorption device, contacting it with the first desulfurization adsorbent to perform first sulfide adsorption, and obtaining first desulfurized hydrogen gas; then introducing the first desulfurized hydrogen gas into the decarbonization unit; S202, when C1 reaches a first concentration threshold C 01 When the hydrogen feedstock is stopped from being introduced into the first desulfurization adsorption unit, the hydrogen feedstock is introduced into the second desulfurization adsorption unit to contact the second desulfurization adsorbent for second sulfide adsorption, thereby obtaining second desulfurized hydrogen; then the second desulfurized hydrogen is introduced into the decarbonization unit; and the first desulfurization adsorbent is regenerated and desorbed; S203, when C1 reaches the first concentration threshold C 01 When the hydrogen feedstock is introduced into the second desulfurization adsorption device, the hydrogen feedstock is introduced into the first desulfurization adsorption device; and the second desulfurization adsorbent is regenerated and desorbed; S204, repeat steps S201 to S203.

[0014] Optionally, the decarbonization unit includes a first decarbonization adsorption device and a second decarbonization adsorption device arranged in parallel. The method further includes: S301, introducing desulfurized hydrogen from the desulfurization unit into the first decarbonization adsorption device, contacting it with the first decarbonization adsorbent to perform first carbon monoxide adsorption, and obtaining first product hydrogen; S302, when C2 reaches a second concentration threshold C 02 When the desulfurized hydrogen gas from the desulfurization unit is stopped being introduced into the first decarbonization adsorption device, the desulfurized hydrogen gas is introduced into the second decarbonization adsorption device to contact the second decarbonization adsorbent for second carbon monoxide adsorption, and the second product hydrogen gas is obtained; and the first decarbonization adsorbent is regenerated and desorbed; S303, when C2 reaches the second concentration threshold C 02 When the desulfurization hydrogen from the desulfurization unit is introduced into the second decarbonization adsorption device, the desulfurization hydrogen from the desulfurization unit is introduced into the first decarbonization adsorption device; and the second decarbonization adsorbent is regenerated and desorbed; S304, repeat steps S301 to S303.

[0015] Optionally, the regeneration desorption in step S202 includes the following steps: extracting the gas from the first desulfurization adsorption device and returning the gas to the first desulfurization adsorption device via a first external pipeline; preferably, the method further includes: heating the gas after extracting it from the first desulfurization adsorption device, so that the heated gas is returned to the first desulfurization adsorption device; the regeneration desorption in step S203 includes the following steps: extracting the gas from the second desulfurization adsorption device and returning the gas to the second desulfurization adsorption device via a second external pipeline; preferably, the method further includes: heating the gas after extracting it from the second desulfurization adsorption device, so that the heated gas is returned to the second desulfurization adsorption device.

[0016] Optionally, the regeneration desorption in step S302 includes the following steps: extracting the gas from the first decarbonization adsorption device and returning the gas to the first decarbonization adsorption device via a third external pipeline; preferably, the method further includes: heating the gas after extracting it from the first decarbonization adsorption device, so that the heated gas is returned to the first decarbonization adsorption device; the regeneration desorption in step S303 includes the following steps: extracting the gas from the second decarbonization adsorption device and returning the gas to the second decarbonization adsorption device via a fourth external pipeline; preferably, the method further includes: heating the gas after extracting it from the second decarbonization adsorption device, so that the heated gas is returned to the second decarbonization adsorption device.

[0017] Optionally, the method further includes: detecting the sulfide concentration C1 and carbon monoxide concentration C2 of the hydrogen outlet gas from the decarbonization unit, respectively; when C1 is equal to a first concentration threshold C... 01 Below, and C2 is the second concentration threshold C. 02 In the following case, the hydrogen gas exiting the decarbonization unit is output as product hydrogen gas.

[0018] Optionally, the first desulfurization adsorbent and the second desulfurization adsorbent are both sulfide adsorbents, and the sulfide adsorbent includes manganese oxide molecular sieves; preferably, the manganese oxide molecular sieves are selected from one or more of sodium manganese ore, bosellite, hydroxyl manganese ore, manganese barium ore, manganese potassium ore, and calcium manganese ore; preferably, the manganese oxide molecular sieves have a BET specific surface area of ​​50-400 m2 / g, a pore volume of 0.3-1, and a weight ratio of manganese to oxygen of 1.5-2.5:1.

[0019] Optionally, the sulfide adsorbent is prepared by a method comprising the following steps:

[0020] A hydrothermal synthesis reaction is carried out by an aqueous solution containing oxidized manganese compounds and reduced manganese compounds. The solid product is collected, washed, dried, and calcined.

[0021] Optionally, the oxidized manganese compound is selected from one or more of potassium permanganate, potassium manganate, and sodium permanganate, and the reduced manganese compound is selected from one or more of manganese sulfate, manganese nitrate, manganese acetate, and manganese chloride; preferably, the molar ratio of the oxidized manganese compound to the reduced manganese compound is (0.2-3):1; optionally, the temperature of the hydrothermal synthesis reaction is 60-200℃, and the reaction time is 1-36h; optionally, the drying temperature is 80-350℃, and the time is 1-24h, and the calcination temperature is 200-900℃, and the time is 0.5-12h; optionally, before the hydrothermal synthesis reaction, acid is added to the aqueous solution to adjust the pH value of the aqueous solution to 0.2-3.

[0022] Optionally, the first decarbonization adsorbent and the second decarbonization adsorbent are both carbon monoxide adsorbents; the carbon monoxide adsorbent includes a support and a first active component and a second active component loaded on the support; the first active component includes a monovalent copper compound and / or a divalent copper compound; the second active component includes a nickel compound; the support includes activated carbon, and the specific surface area of ​​the activated carbon is 400-2000 m². 2 / g; Optionally, the first active component is selected from one or more of cuprous oxide, copper oxide, cuprous chloride, copper chloride, cuprous nitrate, copper nitrate, cuprous sulfate, copper acetate, copper formate, and copper sulfate; the second active component is selected from one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel citrate; based on the total mass of the carbon monoxide adsorbent, the content of the first active component is 25-50% by weight; the content of the second active component is 3-10% by weight; the ratio of the first active component to the second active component... The weight ratio is (0.4-1.2):(0.075-0.15); preferably, the carbon monoxide adsorbent is in any one of spherical, columnar, or sheet-like shapes; when the carbon monoxide adsorbent is spherical, the particle size is 1-3 mm; when the carbon monoxide adsorbent is columnar, the cross-sectional diameter is 1-3 mm and the length is 5-20 mm; when the carbon monoxide adsorbent is sheet-like, the thickness is 0.5-2 mm; preferably, the BET specific surface area of ​​the carbon monoxide adsorbent is 300-1200 m². 2 / g, average pore size 0.3–2nm, pore volume 0.25–0.6cm³ 3 / g.

[0023] Optionally, the carbon monoxide adsorbent is prepared by the following steps: a) mixing the first active component precursor and the second active component precursor with water to obtain a precursor solution; b) immersing the carrier in the precursor solution to obtain a mixture; c) drying and calcining the mixture.

[0024] Optionally, in step a, the first active component precursor is a water-soluble copper salt, preferably selected from one or more of copper chloride, copper nitrate, copper acetate, copper formate, and copper sulfate; the second active component precursor is a water-soluble nickel salt, preferably selected from one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel citrate; and the BET specific surface area of ​​the carrier is 300–2000 m². 2 / g, pore size 0.5~0.8cm 3 / g; In step b, the impregnation temperature is 25-70℃ and the impregnation time is 0.5-4h; In step c, the drying temperature is 60-110℃ and the drying time is 2-8h; The calcination temperature is 240-300℃ and the calcination time is 3-6h, and the calcination atmosphere is argon or nitrogen.

[0025] Optionally, the adsorption operation pressure for the sulfide adsorption in the desulfurization unit is the same as the pressure of the hydrogen feedstock, wherein the pressure of the hydrogen feedstock is 1.5–6.0 MPa; optionally, the conditions for sulfide adsorption in the desulfurization unit include: an adsorption temperature of 20–150°C, preferably 80–120°C, and a volume hourly space velocity of 1000–9000 h⁻¹. -1 Preferably 2000-4000h -1 Optionally, the packing density of the naturally accumulated sulfide adsorbent in each of the two desulfurization adsorption devices in the desulfurization unit is independently 0.4–0.8 g / mL, preferably 0.5–0.7 g / mL; Optionally, the conditions for carbon monoxide adsorption in the decarbonization unit include: an operating pressure of 1.5–6.0 MPa for the decarbonization adsorption device, an adsorption temperature of 10–60°C, preferably 10–40°C, and a volume hourly space velocity of 1000–9000 h⁻¹. -1 Preferably 2000-4000h -1 Optionally, the packing density of the naturally accumulated carbon monoxide adsorbent in each of the two decarbonization adsorption devices in the decarbonization unit is independently 0.4–0.8 g / mL, preferably 0.5–0.7 g / mL; preferably, the weight ratio of the desulfurization adsorbent packed in one desulfurization adsorption device in the desulfurization unit to the decarbonization adsorbent packed in one decarbonization adsorption device in the decarbonization unit is 0.8–1.2:1; optionally, the concentration of carbon monoxide in the hydrogen feedstock is 1–500 ppm, and the concentration of the total sulfide content is 1–50 ppm, wherein the sulfides include at least one of hydrogen sulfide and carbonyl sulfide.

[0026] Optionally, in step S2, during the desorption and regeneration process of the desulfurization adsorption unit, the gas pressure inside the desulfurization adsorption unit is 0.01–2.0 MPa, the temperature is 300–500 °C, and the desorption and regeneration time is 2–8 h.

[0027] During the desorption and regeneration process of the decarbonization adsorption device, the gas pressure inside the device is 0.01–2.0 MPa, the temperature is 80–200℃, and the desorption and regeneration time is 2–8 hours.

[0028] The second aspect of this disclosure provides a two-stage fuel cell-grade hydrogen purification system, comprising, sequentially along the hydrogen feedstock flow direction, a desulfurization adsorption unit and a decarbonization adsorption unit; the desulfurization unit includes: two desulfurization adsorption devices arranged in parallel, each including a desulfurization adsorbent bed and a sulfide detector; the sulfide detector is used to detect the sulfide concentration of the hydrogen at the device outlet; and a first switching control device for controlling the hydrogen feedstock to alternately enter the two desulfurization adsorption devices according to the sulfide concentration of the outlet hydrogen; the decarbonization unit includes: two decarbonization adsorption devices arranged in parallel, each including a decarbonization adsorbent bed and a carbon monoxide detector, the carbon monoxide detector being used to detect the carbon monoxide concentration of the hydrogen at the device outlet; and a second switching control device for controlling the hydrogen from the desulfurization adsorption unit to alternately enter the two decarbonization adsorption devices according to the carbon monoxide concentration of the outlet hydrogen.

[0029] Optionally, the system further includes a first side-line desorption and regeneration unit, a second side-line desorption and regeneration unit, a raw material conveying pipeline, and a product hydrogen pipeline; the desulfurization adsorption unit includes a raw material hydrogen inlet and a desulfurization hydrogen outlet, and the decarbonization adsorption unit includes a desulfurization hydrogen inlet and a product hydrogen outlet; the inlet end of the raw material conveying pipeline is connected to the hydrogen raw material processed by the PSA unit, and the outlet end of the raw material conveying pipeline is connected to the raw material hydrogen inlet of the desulfurization adsorption unit; the desulfurization hydrogen outlet of the desulfurization adsorption unit is connected to the desulfurization hydrogen inlet of the decarbonization unit; the inlet and outlet of each desulfurization adsorption device in the desulfurization unit are respectively connected to the first side-line desorption and regeneration unit; the inlet and outlet of each decarbonization adsorption device in the decarbonization unit are respectively connected to the second side-line desorption and regeneration unit.

[0030] Optionally, the desulfurization unit includes a first desulfurization adsorption device and a second desulfurization adsorption device arranged in parallel; the system also includes a first feed pipe, a first desulfurization hydrogen discharge pipe, a second feed pipe, a second desulfurization hydrogen discharge pipe, and a desulfurization hydrogen conveying pipeline; the outlet end of the feed pipe is connected to the inlet end of the first feed pipe and the inlet end of the second feed pipe, respectively; and the inlet ends of the first and second feed pipes form the feed hydrogen inlet of the desulfurization unit; the first desulfurization adsorption device is provided with a first feed hydrogen inlet and a first desulfurization hydrogen outlet; a first desulfurization adsorbent bed is provided between the first feed hydrogen inlet and the first hydrogen outlet; The first raw material hydrogen inlet is connected to the outlet end of the first raw material feed branch pipe for introducing hydrogen raw material treated by the PSA unit into the first desulfurization adsorption device; the first desulfurization hydrogen outlet is connected to the inlet end of the first desulfurization hydrogen outlet branch pipe; the second desulfurization adsorption device is provided with a second raw material hydrogen inlet and a second desulfurization hydrogen outlet; a second desulfurization adsorbent bed is provided between the second raw material hydrogen inlet and the second hydrogen outlet; the second raw material hydrogen inlet is connected to the outlet end of the second raw material feed branch pipe for introducing hydrogen raw material treated by the PSA unit into the second desulfurization adsorption device; the second desulfurization hydrogen outlet is connected to the inlet end of the second desulfurization hydrogen outlet branch pipe; the desulfurization The outlet of the first branch pipe for hydrogen discharge and the outlet of the second branch pipe for desulfurized hydrogen discharge form the desulfurized hydrogen outlet of the desulfurization unit, and are respectively connected to the inlet end of the desulfurized hydrogen conveying pipeline; the first inlet of raw material hydrogen and the first outlet of desulfurized hydrogen of the first desulfurization adsorption device are respectively connected to the first side-line desorption and regeneration unit; the second inlet of raw material hydrogen and the second outlet of desulfurized hydrogen of the second desulfurization adsorption device are respectively connected to the first side-line desorption and regeneration unit; the decarbonization unit includes two parallel first decarbonization adsorption devices and a second decarbonization adsorption device; the system also includes a first branch pipe for desulfurized hydrogen feed, a first branch pipe for product hydrogen discharge, a second branch pipe for desulfurized hydrogen feed, and a second branch pipe for product hydrogen discharge; The inlet ends of the first and second desulfurization hydrogen feed branches are respectively connected to the outlet ends of the desulfurization hydrogen conveying pipeline, and the inlet ends of the first and second desulfurization hydrogen feed branches form the desulfurization hydrogen inlet of the decarbonization unit; the first decarbonization adsorption device is provided with a first desulfurization hydrogen inlet and a first product hydrogen outlet; a first decarbonization adsorbent bed is provided between the first desulfurization hydrogen inlet and the first product hydrogen outlet; the first desulfurization hydrogen inlet is connected to the outlet end of the first desulfurization hydrogen feed branch for introducing desulfurization hydrogen from the desulfurization unit into the first decarbonization adsorption device; the first product hydrogen outlet is connected to the inlet end of the first product hydrogen outlet branch.The second decarbonization adsorption device is equipped with a second desulfurization hydrogen inlet and a second product hydrogen outlet; a second decarbonization adsorbent bed is provided between the second desulfurization hydrogen inlet and the second product hydrogen outlet; the second desulfurization hydrogen inlet is connected to the outlet end of the second branch pipe for feeding desulfurization hydrogen to introduce desulfurization hydrogen from the desulfurization unit into the second decarbonization adsorption device; the second product hydrogen outlet is connected to the inlet end of the second branch pipe for discharging product hydrogen; the first desulfurization hydrogen inlet and the first product hydrogen outlet of the first decarbonization adsorption device are respectively connected to the second side-line desorption and regeneration unit; the second desulfurization hydrogen inlet and the second product hydrogen outlet of the second decarbonization adsorption device are respectively connected to the second side-line desorption and regeneration unit.

[0031] Optionally, the first side-line desorption and regeneration unit includes a first circulation main pipe, a first side-line front branch pipe, a first side-line rear branch pipe, a second side-line front branch pipe, and a second side-line rear branch pipe; the first desulfurized hydrogen outlet of the first desulfurization adsorption device is connected to the first feed hydrogen inlet of the first desulfurization adsorption device in sequence through the first side-line front branch pipe, the first circulation main pipe, and the first side-line rear branch pipe; a first side-line front branch pipe desorption valve is provided on the first side-line front branch pipe, and a first side-line rear branch pipe desorption valve is provided on the first side-line rear branch pipe; the second desulfurized hydrogen outlet of the second desulfurization adsorption device is connected to the second feed hydrogen inlet of the second desulfurization adsorption device in sequence through the second side-line front branch pipe, the first circulation main pipe, and the second side-line rear branch pipe. The second side line front branch pipe is equipped with a second side line front branch pipe desorption valve, and the second side line rear branch pipe is equipped with a second side line rear branch pipe desorption valve; the first circulation main pipe is connected to a first gas circulation pump and an optional first heating device; the heating inlet of the first heating device is connected to the suction outlet of the first gas circulation pump, and the heating outlet of the first heating device is connected to the first raw material hydrogen inlet of the first desulfurization adsorption device via the first side line rear branch pipe desorption valve, and to the second raw material hydrogen inlet of the second desulfurization adsorption device via the second side line rear branch pipe desorption valve; optionally, the system further includes a first feed valve, a first discharge valve, a second feed valve, and a second discharge valve; the first feed valve is located at the hydrogen raw material feed first... On the branch pipes, the first discharge valve is located on the first branch pipe for desulfurized hydrogen discharge; the second feed valve is located on the second branch pipe for hydrogen feed, and the second discharge valve is located on the second branch pipe for desulfurized hydrogen discharge; optionally, the system further includes a first hydrogen release pipeline and a first hydrogen release valve, the first hydrogen release valve being located on the first hydrogen release pipeline, and the inlet end of the first hydrogen release pipeline being connected to the outlet of the first branch pipe for desulfurized hydrogen discharge and the outlet of the second branch pipe for desulfurized hydrogen discharge respectively; optionally, the second side-line desorption regeneration unit includes a second circulation main pipe, a third side-line front branch pipe, a third side-line rear branch pipe, a fourth side-line front branch pipe, and a fourth side-line rear branch pipe; the first product hydrogen from the first decarbonization adsorption device is discharged. The outlet of the second product hydrogen gas of the second decarbonization adsorption device is connected to the first inlet of the desulfurized hydrogen gas of the first decarbonization adsorption device via the third side line front branch pipe, the second circulation main pipe, and the fourth side line rear branch pipe in sequence. The third side line front branch pipe is equipped with a desorption valve, and the third side line rear branch pipe is equipped with a desorption valve. The outlet of the second product hydrogen gas of the second decarbonization adsorption device is connected to the second inlet of the desulfurized hydrogen gas of the second decarbonization adsorption device via the fourth side line front branch pipe, the second circulation main pipe, and the fourth side line rear branch pipe in sequence. The fourth side line front branch pipe is equipped with a desorption valve, and the fourth side line rear branch pipe is equipped with a desorption valve. The second circulation main pipe is connected to a second gas circulation pump and an optional second heating device.The heating inlet of the second heating device is connected to the suction outlet of the second gas circulation pump. The heating outlet of the second heating device is connected to the first inlet of the raw material hydrogen of the first decarbonization adsorption device via the desorption valve of the third side branch pipe, and to the second inlet of the desulfurized hydrogen of the second decarbonization adsorption device via the desorption valve of the fourth side branch pipe. Optionally, the system further includes a third feed valve, a third discharge valve, a fourth feed valve, and a fourth discharge valve. The third feed valve is located on the first branch pipe for desulfurized hydrogen feeding, and the third discharge valve is located on the first branch pipe for product hydrogen discharge. The fourth feed valve is located on the second branch pipe for desulfurized hydrogen feeding, and the fourth discharge valve is located on the second branch pipe for product hydrogen discharge. Optionally, the system further includes a second hydrogen release pipeline and a second hydrogen release valve. The second hydrogen release valve is located on the second hydrogen release pipeline, and the inlet end of the second hydrogen release pipeline is connected to the outlet of the first branch pipe for product hydrogen discharge and the outlet of the second branch pipe for product hydrogen discharge, respectively.

[0032] Through the above technical solution, this disclosure provides a two-stage fuel cell-grade hydrogen purification method and system. In this disclosure, the high-purity hydrogen feedstock purified from the PSA unit is first subjected to a desulfurization adsorption device in the desulfurization unit to adsorb trace amounts of sulfides (such as hydrogen sulfide and carbonyl sulfide), and then the desulfurized hydrogen is introduced into the decarbonization adsorption device in the decarbonization unit to adsorb and remove trace amounts of carbon monoxide, thereby achieving effective removal of trace amounts of sulfides and carbon monoxide from the high-purity hydrogen. This disclosure features two desulfurization adsorption devices connected in parallel in the desulfurization unit and two decarbonization adsorption devices connected in parallel in the decarbonization unit. In both units, when one adsorption device is in adsorption mode, the other is in adsorbent desorption / regeneration or standby mode. Simultaneously, the concentrations of sulfides and carbon monoxide in the outlet hydrogen from the decarbonization unit are monitored. When the concentration of either substance reaches its threshold, the other adsorption device is immediately switched to perform adsorption, and the desulfurization or decarbonization adsorbent in the stopped adsorption device is desorbed and regenerated. This disclosure effectively adsorbs sulfides and carbon monoxide without continuous pressure swing cycle adsorption, has a long single adsorption cycle, and is more convenient to operate and start / stop. It improves hydrogen purity and ensures hydrogen yield while simultaneously producing hydrogen for fuel cells. Furthermore, this disclosure allows for independent switching and desorption / regeneration of the desulfurization adsorption devices in the desulfurization unit and the decarbonization adsorption devices in the decarbonization unit, further enhancing desulfurization and decarbonization efficiency. This disclosure connects the desulfurization adsorption unit and the decarbonization adsorption unit, which have the same or similar operating temperatures and pressures, and perform desulfurization under conditions close to PSA outlet gas. This effectively reduces energy consumption and operational complexity, ensuring low-cost and high-efficiency production. The desulfurization and decarbonization adsorbents used in this disclosure are more targeted, with superior adsorption capacity and removal depth.

[0033] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0034] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0035] Figure 1 This is a schematic flowchart of a two-stage fuel cell-grade hydrogen purification method provided in this disclosure;

[0036] Figure 2 This is a schematic diagram of a two-stage fuel cell-grade hydrogen purification system provided in this disclosure;

[0037] Figure 3 The XRD pattern is shown for the desulfurization adsorbent in Example 2 of this disclosure.

[0038] Explanation of reference numerals in the attached figures

[0039] A - Desulfurization unit, B - Decarbonization unit, 1 - First desulfurization adsorption device, 2 - Second desulfurization adsorption device, 3 - First decarbonization adsorption device, 4 - Second decarbonization adsorption device, 5 - Hydrogen feedstock, 6 - Desulfurized hydrogen, 7 - Product hydrogen, 8 - First feed valve, 9 - First discharge valve, 10 - Second feed valve, 11 - Second discharge valve, 12 - Third feed valve, 13 - Third discharge valve, 14 - Fourth feed valve, 15 - Fourth discharge valve, 16 - First side line branch pipe, 17 - 18 - Rear branch pipe of the first side line; 19 - Front branch pipe of the second side line; 20 - Rear branch pipe of the second side line; 21 - First gas circulation pump; 22 - First heating device; 23 - First hydrogen release valve; 24 - Front branch pipe of the third side line; 25 - Desorption valve of the rear branch pipe of the third side line; 26 - Front branch pipe of the fourth side line; 27 - Rear branch pipe of the fourth side line; 28 - Second gas circulation pump; 29 - Second heating device; 30 - Second hydrogen release valve; 31 - First hydrogen release pipeline. Detailed Implementation

[0040] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0041] In this disclosure, unless otherwise stated, the terms "first," "second," and "third" are used only to distinguish different components and do not imply any actual connection order. In this disclosure, directional terms such as "upper" and "lower" refer to the upper and lower positions of the device in its normal operating state, while "inner" and "outer" refer to the outline of the device.

[0042] The first aspect of this disclosure provides a two-stage fuel cell stage hydrogen purification method, such as... Figure 1 As shown, it includes the following steps:

[0043] S1. The hydrogen feedstock from the PSA unit is introduced into one of the two desulfurization adsorption devices in the desulfurization unit, where it comes into contact with the desulfurization adsorbent to adsorb sulfides and obtain desulfurized hydrogen.

[0044] Then, the desulfurized hydrogen from the desulfurization unit is introduced into one of the two decarbonization adsorption devices in the decarbonization unit, where it comes into contact with the decarbonization adsorbent to adsorb carbon monoxide and obtain product hydrogen.

[0045] Monitor the concentrations of sulfide (C1) and carbon monoxide (C2) in the hydrogen gas exiting the decarbonization unit.

[0046] S2, When C1 reaches the first concentration threshold C 01 When the hydrogen feedstock is stopped from being introduced into the desulfurization adsorption unit in the desulfurization unit, the hydrogen feedstock is introduced into the other of the two desulfurization adsorption units in the desulfurization unit to contact the desulfurization adsorbent for sulfide adsorption; and the desulfurization adsorbent in the desulfurization adsorption unit that has stopped operating is regenerated and desorbed, or the desulfurization adsorbent in the desulfurization adsorption unit that has stopped operating is replaced with fresh desulfurization adsorbent; and

[0047] When C2 reaches the second concentration threshold C 02 When the desulfurized hydrogen is introduced into the decarbonization adsorption device in the decarbonization unit, the desulfurized hydrogen is introduced into the other of the two decarbonization adsorption devices in the decarbonization unit to adsorb carbon monoxide and obtain product hydrogen; and the decarbonization adsorbent in the decarbonization adsorption device that has stopped working is regenerated and desorbed.

[0048] S3, Repeat steps S1 to S2; where C 01 The concentration was 0.003–0.004 ppm, C 02 The concentration is 0.18–0.20 ppm.

[0049] This disclosure provides a method for purifying hydrogen in a segmented fuel cell. The high-purity hydrogen feedstock purified from the PSA unit is first subjected to a desulfurization adsorption device in the desulfurization unit to adsorb trace amounts of sulfides (such as hydrogen sulfide and carbonyl sulfide). Then, the desulfurized hydrogen is introduced into the decarbonization adsorption device in the decarbonization unit to adsorb and remove trace amounts of carbon monoxide, thereby achieving effective removal of trace amounts of sulfides and carbon monoxide from the high-purity hydrogen. This disclosure features two desulfurization adsorption devices connected in parallel in the desulfurization unit and two decarbonization adsorption devices connected in parallel in the decarbonization unit. In both units, when one adsorption device is in adsorption mode, the other is in adsorbent desorption / regeneration or standby mode. Simultaneously, the concentrations of sulfides and carbon monoxide in the outlet hydrogen from the decarbonization unit are monitored. When the concentration of either substance reaches its threshold, the other adsorption device is immediately switched to perform adsorption, and the desulfurization or decarbonization adsorbent in the stopped adsorption device is desorbed and regenerated. This disclosure effectively adsorbs sulfides and carbon monoxide without continuous pressure swing cycle adsorption, has a long single adsorption cycle, and is more convenient to operate and start / stop. It improves hydrogen purity and ensures hydrogen yield while simultaneously producing hydrogen for fuel cells. Furthermore, this disclosure allows for independent switching and desorption / regeneration of the desulfurization adsorption devices in the desulfurization unit and the decarbonization adsorption devices in the decarbonization unit, further enhancing desulfurization and decarbonization efficiency. This disclosure connects the desulfurization adsorption unit and the decarbonization adsorption unit, which have the same or similar operating temperatures and pressures, and perform desulfurization under conditions close to PSA outlet gas. This effectively reduces energy consumption and operational complexity, ensuring low-cost and high-efficiency production. The desulfurization and decarbonization adsorbents used in this disclosure are more targeted, with superior adsorption capacity and removal depth.

[0050] In this disclosure, the range of the first concentration threshold and the second concentration threshold means that any value within the range can be used as a standard, and can be selected according to the actual situation. For example, the first concentration threshold C 01 The value is 0.003 to 0.004 ppm, and you can choose values ​​such as 0.003 ppm, 0.0035 ppm, or 0.0004 ppm depending on the actual situation.

[0051] In one specific embodiment, the concentration of carbon monoxide in the hydrogen feedstock is 1 to 500 ppm, and the concentration of the total sulfide content is 1 to 50 ppm, wherein the sulfide includes at least one of hydrogen sulfide and carbonyl sulfide.

[0052] In one embodiment, the desulfurization unit includes a first desulfurization adsorption device and a second desulfurization adsorption device arranged in parallel, and the method further includes:

[0053] S201. Hydrogen feedstock is introduced into the first desulfurization adsorption device and comes into contact with the first desulfurization adsorbent to perform first sulfide adsorption, thereby obtaining first desulfurized hydrogen gas; then the first desulfurized hydrogen gas is introduced into the decarbonization unit.

[0054] S202, When C1 reaches the first concentration threshold C 01 When the hydrogen feedstock is introduced into the first desulfurization adsorption unit, the hydrogen feedstock is introduced into the second desulfurization adsorption unit to contact the second desulfurization adsorbent for second sulfide adsorption, thereby obtaining second desulfurized hydrogen; then the second desulfurized hydrogen is introduced into the decarbonization unit; and the first desulfurization adsorbent is regenerated and desorbed.

[0055] S203, When C1 reaches the first concentration threshold C 01 When the hydrogen feedstock is introduced into the second desulfurization adsorption unit, the hydrogen feedstock is introduced into the first desulfurization adsorption unit; and the second desulfurization adsorbent is regenerated and desorbed.

[0056] S204. Repeat steps S201 to S203.

[0057] In one embodiment, the decarbonization unit includes a first decarbonization adsorption device and a second decarbonization adsorption device arranged in parallel, and the method further includes:

[0058] S301. Desulfurized hydrogen from the desulfurization unit is introduced into the first decarbonization adsorption device, and comes into contact with the first decarbonization adsorbent to perform first carbon monoxide adsorption, thereby obtaining the first product hydrogen.

[0059] S302, When C2 reaches the second concentration threshold C 02 When the desulfurization hydrogen gas from the desulfurization unit is introduced into the first decarbonization adsorption device, the desulfurization hydrogen gas is introduced into the second decarbonization adsorption device to contact the second decarbonization adsorbent for second carbon monoxide adsorption to obtain the second product hydrogen gas; and the first decarbonization adsorbent is regenerated and desorbed.

[0060] S303, When C2 reaches the second concentration threshold C 02 At this time, the introduction of desulfurized hydrogen gas from the desulfurization unit into the second decarbonization adsorption device is stopped, and the desulfurized hydrogen gas from the desulfurization unit is allowed to enter the first decarbonization adsorption device; and the second decarbonization adsorbent is regenerated and desorbed.

[0061] S304. Repeat steps S301 to S303.

[0062] This disclosure enables independent control of two desulfurization adsorption devices connected in parallel in the desulfurization unit and two decarbonization adsorption devices connected in parallel in the decarbonization unit. This allows for rapid switching to another standby adsorption device once the adsorbent in the desulfurization and decarbonization units reaches saturation, ensuring that the desulfurization and decarbonization processes proceed under favorable conditions and further improving hydrogen treatment efficiency. In particular, timely switching of the saturated adsorption device in the desulfurization unit also ensures that the sulfide content of the desulfurized hydrogen entering the decarbonization unit is as low as possible, thereby reducing the performance damage caused by sulfides to the decarbonization adsorbent and improving the overall operating cycle of the unit.

[0063] In this disclosure, when C1 reaches the first concentration threshold C 01 When the hydrogen feedstock is stopped from being introduced into the first desulfurization adsorption device, the desulfurization adsorbent can be desorbed and regenerated, or a new desulfurization adsorbent can be directly replaced.

[0064] In one specific embodiment, the regeneration and desorption in step S202 includes the following steps:

[0065] The gas in the first desulfurization adsorption device is extracted and returned to the first desulfurization adsorption device through a first external pipeline; preferably, the method further includes: heating the gas after extracting it from the first desulfurization adsorption device, and returning the heated gas to the first desulfurization adsorption device.

[0066] The regeneration and desorption described in step S203 includes the following steps: extracting the gas from the second desulfurization adsorption device and returning the gas to the second desulfurization adsorption device through a second external pipeline; preferably, the method further includes: heating the gas after extracting it from the second desulfurization adsorption device and returning the heated gas to the second desulfurization adsorption device.

[0067] In one embodiment, the regeneration and desorption in step S302 includes the following steps:

[0068] The gas in the first decarbonization adsorption device is extracted and returned to the first decarbonization adsorption device through a third external pipeline; preferably, the method further includes: heating the gas after extracting it from the first decarbonization adsorption device, and returning the heated gas to the first decarbonization adsorption device.

[0069] The regeneration and desorption described in step S303 includes the following steps: extracting the gas from the second decarbonization adsorption device and returning the gas to the second decarbonization adsorption device via a fourth external pipeline; preferably, the method further includes: heating the gas after extracting it from the second decarbonization adsorption device and returning the heated gas to the second decarbonization adsorption device.

[0070] See Figure 2The following describes the specific process flow of desulfurization and regeneration of the first desulfurization adsorbent in the first desulfurization adsorption unit, taking the desulfurization adsorption unit as an example:

[0071] Gas is extracted from the bottom of the first desulfurization adsorption unit outside the tower using an extraction device (e.g., an extraction pump). The gas temperature can then be increased by heating the gas through an external pipeline. The gas flow is then introduced back into the first desulfurization adsorption unit via the external pipeline, achieving gas circulation within the unit. During this circulation, the gas pressure inside the adsorption unit decreases, causing the first desulfurization adsorbent to desorb under low-pressure conditions. Furthermore, the heating of the circulating gas further enhances the desorption and regeneration efficiency of the first desulfurization adsorbent. In this disclosure, after stopping the introduction of hydrogen into the first desulfurization adsorption unit and before desorption and regeneration, some hydrogen can be released to reduce the gas pressure before proceeding with desorption and regeneration. The second desulfurization adsorption unit and the first and second decarbonization adsorption units within the decarbonization unit have similar process flows for adsorbent desorption and regeneration.

[0072] In a preferred embodiment, in step S2, during the desorption and regeneration process of the desulfurization adsorption device, the gas pressure inside the desulfurization adsorption device is 0.01–2.0 MPa, the temperature is 300–500 °C, and the desorption and regeneration time is 2–8 h.

[0073] During the desorption and regeneration process of the decarbonization adsorption device, the gas pressure inside the device is 0.01–2.0 MPa, the temperature is 80–200℃, and the desorption and regeneration time is 2–8 hours.

[0074] In one embodiment, the method further includes: detecting the sulfide concentration C1 of the hydrogen outlet gas from the decarbonization unit and the carbon monoxide concentration C2, respectively; when C1 is a first concentration threshold C... 01 Below, and C2 is the second concentration threshold C. 02 In the following cases, the hydrogen gas exiting the decarbonization unit is output as product hydrogen gas. Specifically, the concentration can be detected using detection methods commonly used in the art, such as pre-concentration-gas chromatography-sulfur chemiluminescence detection for detecting sulfide concentration, and gas chromatography-pulse helium ionization detection for detecting carbon monoxide concentration.

[0075] In this disclosure, the selective adsorption device detects the carbon monoxide and sulfide concentrations of the output hydrogen, and outputs product hydrogen that simultaneously meets the thresholds for both carbon monoxide and sulfide concentrations. When the concentration reaches either the carbon monoxide or sulfide concentration threshold, the introduction of hydrogen feedstock into the adsorption device can be stopped in a timely manner, effectively ensuring that the carbon monoxide and sulfide concentrations of the output product hydrogen meet the quality standards for fuel-grade hydrogen.

[0076] In one embodiment, the first desulfurization adsorbent and the second desulfurization adsorbent are respectively sulfide adsorbents, and the sulfide adsorbents include manganese oxide molecular sieves; preferably, the manganese oxide molecular sieves are selected from one or more of sodium manganese ore, bosell ore, hydrous manganese ore, manganese barium ore, manganese potassium ore, and calcium manganese ore.

[0077] In a preferred embodiment, the BET specific surface area of ​​the manganese oxide molecular sieve is 50–400 m². 2 / g, pore volume 0.3~1cm³ 3 The weight ratio of manganese and oxygen is 1.5 to 2.5:1.

[0078] In one embodiment, the sulfide adsorbent is prepared by a method comprising the following steps:

[0079] A hydrothermal synthesis reaction is carried out by an aqueous solution containing oxidized manganese compounds and reduced manganese compounds. The solid product is collected, washed, dried, and calcined.

[0080] In one embodiment, the oxidized manganese compound is selected from one or more of potassium permanganate, potassium manganate, and sodium permanganate, and the reduced manganese compound is selected from one or more of manganese sulfate, manganese nitrate, manganese acetate, and manganese chloride; preferably, the molar ratio of the oxidized manganese compound to the reduced manganese compound is (0.2-3):1.

[0081] Optionally, the temperature of the hydrothermal synthesis reaction is 60–200°C, and the reaction time is 1–36 h;

[0082] Optionally, the drying temperature is 80–350°C and the time is 1–24 h, and the calcination temperature is 200–900°C and the time is 0.5–12 h;

[0083] Optionally, prior to the hydrothermal synthesis reaction, an acid is added to the aqueous solution to adjust the pH value of the aqueous solution to 0.2–3.

[0084] In one embodiment, the first decarbonization adsorbent and the second decarbonization adsorbent are both carbon monoxide adsorbents; the carbon monoxide adsorbent includes a support and a first active component and a second active component loaded on the support; the first active component includes a monovalent copper compound and / or a divalent copper compound; the second active component includes a nickel compound; the support includes activated carbon, and the specific surface area of ​​the activated carbon is 400-2000 m². 2 / g;

[0085] Optionally, the first active component is selected from one or more of cuprous oxide, copper oxide, cuprous chloride, cuprous chloride, cuprous nitrate, copper nitrate, cuprous sulfate, copper acetate, copper formate, and copper sulfate; the second active component is selected from one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel citrate; based on the total mass of the carbon monoxide adsorbent, the content of the first active component is 25-50% by weight; the content of the second active component is 3-10% by weight; and the weight ratio of the first active component to the second active component is (0.4-1.2):(0.075-0.15).

[0086] Preferably, the carbon monoxide adsorbent is in any one of the following shapes: spherical, columnar, or sheet-like.

[0087] When the carbon monoxide adsorbent is in the form of spherical particles, the particle size is 1-3 mm; when the carbon monoxide adsorbent is in the form of columns, the cross-sectional diameter is 1-3 mm and the length is 5-20 mm; when the carbon monoxide adsorbent is in the form of flakes, the thickness is 0.5-2 mm.

[0088] Preferably, the BET specific surface area of ​​the carbon monoxide adsorbent is 300–1200 m². 2 / g, average pore size 0.3–2nm, pore volume 0.25–0.6cm³ 3 / g.

[0089] The carbon monoxide adsorbent obtained by introducing a first active combination and a second active component into the carrier in this disclosure can be used as a packing layer in a fixed-bed adsorption device to achieve effective adsorption of trace amounts of carbon monoxide in hydrogen, thereby improving the practical applicability of this disclosure.

[0090] In one embodiment, the carbon monoxide adsorbent can be prepared by the following steps:

[0091] a. Mix the first active component precursor and the second active component precursor with water to obtain a precursor solution;

[0092] b. Immerse the carrier in the precursor solution to obtain a mixture;

[0093] c. Dry and calcine the mixture.

[0094] The carbon monoxide adsorbent prepared by the method provided in this disclosure can load the first and second active components into the pores and surface of the support. The structure, size and performance of the prepared catalyst are more suitable for industrial applications. It also has higher adsorption efficiency and adsorption capacity for carbon monoxide, and is particularly suitable for the removal of trace carbon monoxide from desulfurized hydrogen feedstock from the desulfurization unit in the selective adsorption device provided in this disclosure.

[0095] In one embodiment, in step a, the first active component precursor is a water-soluble copper salt, preferably selected from one or more of copper chloride, copper nitrate, copper acetate, copper formate, and copper sulfate; the second active component precursor is a water-soluble nickel salt, preferably selected from one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel citrate; the BET specific surface area of ​​the carrier is 300–2000 m². 2 / g, pore size 0.5~0.8cm 3 / g;

[0096] In step b, the immersion temperature is 25–70°C, and the immersion time is 0.5–4 hours.

[0097] In step c, the drying temperature is 60–110℃ and the drying time is 2–8 h; the calcination temperature is 240–300℃ and the calcination time is 3–6 h; the calcination atmosphere is argon or nitrogen.

[0098] In one embodiment, the adsorption operating pressure for the sulfide adsorption in the desulfurization unit is the same as the pressure of the hydrogen feedstock, which is 1.5 to 6.0 MPa. In this disclosure, the operating pressure in the adsorption device does not need to be adjusted during the adsorption process; it can simply be kept the same as the pressure of the hydrogen feedstock, making the operation simpler.

[0099] In one embodiment, the conditions for sulfide adsorption in the desulfurization unit include: an adsorption temperature of 20–150°C, preferably 80–120°C, and a volume hourly space velocity of 1000–9000 h⁻¹. -1 Preferably 2000-4000h -1 ;

[0100] Optionally, the packing density of the naturally accumulated sulfide adsorbent in the two desulfurization adsorption devices in the desulfurization unit is independently 0.4 to 0.8 g / mL, preferably 0.5 to 0.7 g / mL;

[0101] Optionally, the conditions for carbon monoxide adsorption in the decarbonization unit include: an operating pressure of 1.5–6.0 MPa for the decarbonization adsorption device, an adsorption temperature of 10–60°C, preferably 10–40°C, and a volume hourly space velocity of 1000–9000 h⁻¹. -1Preferably 2000-4000h -1 ;

[0102] Optionally, the packing density of the carbon monoxide adsorbent naturally accumulated in the two decarbonization adsorption devices in the decarbonization unit is independently 0.4 to 0.8 g / mL, preferably 0.5 to 0.7 g / mL;

[0103] Preferably, the weight ratio of the desulfurization adsorbent in one desulfurization adsorption device in the desulfurization unit to the decarbonization adsorption agent in one decarbonization adsorption device in the decarbonization unit is 0.8 to 1.2:1.

[0104] Optionally, the concentration of carbon monoxide in the hydrogen feedstock is 1 to 500 ppm, and the concentration of total sulfide content is 1 to 50 ppm, wherein the sulfides include at least one of hydrogen sulfide and carbonyl sulfide.

[0105] The adsorption conditions in this disclosure, such as pressure, temperature, and volumetric hourly space velocity, are better matched to the performance of the sulfide and carbon monoxide adsorbents used in this disclosure and their specific packing methods in the adsorption device, and are also more suitable for the sulfide and carbon monoxide content in the hydrogen feedstock from the PSA unit.

[0106] A second aspect of this disclosure provides a two-stage fuel cell-grade hydrogen purification system, such as... Figure 2 As shown, along the hydrogen feedstock flow direction, there are sequentially a desulfurization adsorption unit and a decarbonization adsorption unit;

[0107] The desulfurization unit includes:

[0108] Two desulfurization adsorption units are connected in parallel. Each desulfurization adsorption unit includes a desulfurization adsorbent bed and a sulfide detector. The sulfide detector is used to detect the sulfide concentration of hydrogen gas at the unit outlet.

[0109] The first switching control device is used to control the alternating entry of hydrogen feedstock into the two desulfurization adsorption units based on the sulfide concentration of the outlet hydrogen.

[0110] The decarbonization unit includes:

[0111] Two decarbonization adsorption units are connected in parallel. Each unit contains a decarbonization adsorbent bed and a carbon monoxide detector, wherein the carbon monoxide detector is used to detect the carbon monoxide concentration in the hydrogen gas at the unit outlet.

[0112] The second switching control device is used to control the alternating entry of hydrogen from the desulfurization adsorption unit into the two decarbonization adsorption devices based on the carbon monoxide concentration of the outlet hydrogen.

[0113] In this disclosure, the first and second switching control devices can be conventionally used control devices known in the art, such as controllers, pipelines, and valves. Taking a decarbonization unit as an example: for instance, a valve can be installed as a feed valve on the hydrogen feedstock inlet pipeline of a decarbonization adsorption unit, and this valve is connected to the controller. The controller controls the opening and closing of the valve based on whether the carbon monoxide concentration detected by the carbon monoxide detector reaches the required concentration threshold. For example, if the carbon monoxide detector detects that the carbon monoxide concentration has not reached the threshold, the controller can keep the valve open, and the original decarbonization adsorber continues to operate. If the carbon monoxide concentration reaches the threshold, the controller closes the valve to stop the introduction of desulfurized hydrogen from the desulfurization unit into the operating decarbonization adsorption unit; and controls another feed valve on the feedstock hydrogen inlet pipeline of another decarbonization adsorption unit to open, allowing desulfurized hydrogen to enter the other decarbonization adsorption unit. Specific configurations can be made according to actual usage.

[0114] In one embodiment, the system further includes a first side-line desorption and regeneration unit, a second side-line desorption and regeneration unit, a raw material conveying pipeline, and a product hydrogen pipeline; the desulfurization adsorption unit includes a raw material hydrogen inlet and a desulfurization hydrogen outlet, and the decarbonization adsorption unit includes a desulfurization hydrogen inlet and a product hydrogen outlet.

[0115] The inlet end of the raw material conveying pipeline is connected to the hydrogen raw material processed by the PSA unit, and the outlet end of the raw material conveying pipeline is connected to the raw material hydrogen inlet of the desulfurization adsorption unit; the desulfurization hydrogen outlet of the desulfurization adsorption unit is connected to the desulfurization hydrogen inlet of the decarbonization unit.

[0116] The inlet and outlet of each desulfurization adsorption device in the desulfurization unit are respectively connected to the first side-line desorption and regeneration unit; the inlet and outlet of each decarbonization adsorption device in the decarbonization unit are respectively connected to the second side-line desorption and regeneration unit.

[0117] In a preferred embodiment, such as Figure 2 As shown, the desulfurization unit includes a first desulfurization adsorption device 1 and a second desulfurization adsorption device 2 arranged in parallel; the system also includes a first branch pipe for raw material feeding, a first branch pipe for desulfurized hydrogen discharge, a second branch pipe for raw material feeding, a second branch pipe for desulfurized hydrogen discharge, and a desulfurized hydrogen conveying pipeline.

[0118] The outlet end of the raw material conveying pipeline is connected to the inlet end of the first raw material feed branch pipe and the inlet end of the second raw material feed branch pipe, respectively; and the inlet end of the first raw material feed branch pipe and the inlet end of the second raw material feed branch pipe form the raw material hydrogen inlet of the desulfurization unit.

[0119] The first desulfurization adsorption unit 1 is provided with a first raw material hydrogen inlet and a first desulfurized hydrogen outlet; a first desulfurization adsorbent bed is provided between the first raw material hydrogen inlet and the first hydrogen outlet; the first raw material hydrogen inlet is connected to the outlet end of the first raw material feed branch pipe for introducing hydrogen raw material 5 after PSA device treatment into the first desulfurization adsorption unit 1; the first desulfurized hydrogen outlet is connected to the inlet end of the first desulfurized hydrogen outlet branch pipe.

[0120] The second desulfurization adsorption unit 2 is provided with a second raw material hydrogen inlet and a second desulfurized hydrogen outlet; a second desulfurization adsorbent bed is provided between the second raw material hydrogen inlet and the second hydrogen outlet; the second raw material hydrogen inlet is connected to the outlet end of the second raw material feed branch pipe for introducing hydrogen raw material 5 after PSA device treatment into the second desulfurization adsorption unit 2; the second desulfurized hydrogen outlet is connected to the inlet end of the second desulfurized hydrogen outlet branch pipe.

[0121] The outlet of the first branch pipe for desulfurized hydrogen discharge and the outlet of the second branch pipe for desulfurized hydrogen discharge form the desulfurized hydrogen outlet of the desulfurization unit, and are respectively connected to the inlet end of the desulfurized hydrogen conveying pipeline.

[0122] The first inlet of raw material hydrogen and the first outlet of desulfurized hydrogen in the first desulfurization adsorption unit 1 are respectively connected to the first side-line desorption and regeneration unit; the second inlet of raw material hydrogen and the second outlet of desulfurized hydrogen in the second desulfurization adsorption unit 2 are respectively connected to the first side-line desorption and regeneration unit.

[0123] The decarbonization unit includes two parallel-connected first decarbonization adsorption devices 3 and second decarbonization adsorption devices 4; the system also includes a first branch pipe for desulfurization hydrogen feed, a first branch pipe for product hydrogen discharge, a second branch pipe for desulfurization hydrogen feed, and a second branch pipe for product hydrogen discharge.

[0124] The inlet ends of the first branch pipe for desulfurized hydrogen gas feed and the second branch pipe for desulfurized hydrogen gas feed are respectively connected to the outlet end of the desulfurized hydrogen gas conveying pipeline, and the inlet ends of the first branch pipe for desulfurized hydrogen gas feed and the second branch pipe for desulfurized hydrogen gas feed form the desulfurized hydrogen gas inlet of the decarbonization unit.

[0125] The first decarbonization adsorption device 3 is provided with a first desulfurization hydrogen inlet and a first product hydrogen outlet; a first decarbonization adsorbent bed is provided between the first desulfurization hydrogen inlet and the first product hydrogen outlet; the first desulfurization hydrogen inlet is connected to the outlet end of the first desulfurization hydrogen feed branch pipe for introducing desulfurization hydrogen from the desulfurization unit into the first decarbonization adsorption device 3; the first product hydrogen outlet is connected to the inlet end of the first product hydrogen outlet branch pipe.

[0126] The second decarbonization adsorption device 4 is provided with a second desulfurization hydrogen inlet and a second product hydrogen outlet; a second decarbonization adsorbent bed is provided between the second desulfurization hydrogen inlet and the second product hydrogen outlet; the second desulfurization hydrogen inlet is connected to the outlet end of the second branch pipe for feeding desulfurization hydrogen to introduce desulfurization hydrogen from the desulfurization unit into the second decarbonization adsorption device 4; the second product hydrogen outlet is connected to the inlet end of the second branch pipe for discharging product hydrogen.

[0127] The first inlet of desulfurized hydrogen and the outlet of first product hydrogen in the first decarbonization adsorption device 3 are respectively connected to the second side-line desorption and regeneration unit; the second inlet of desulfurized hydrogen and the outlet of second product hydrogen in the second decarbonization adsorption device 4 are respectively connected to the second side-line desorption and regeneration unit.

[0128] In a preferred embodiment, the first side-line desorption and regeneration unit includes a first circulation main pipe, a first side-line front branch pipe, a first side-line rear branch pipe, a second side-line front branch pipe, and a second side-line rear branch pipe; the first desulfurization hydrogen outlet of the first desulfurization adsorption device 1 is connected to the first raw material hydrogen inlet of the first desulfurization adsorption device 1 in sequence through the first side-line front branch pipe, the first circulation main pipe, and the first side-line rear branch pipe; a first side-line front branch pipe desorption valve is provided on the first side-line front branch pipe, and a first side-line rear branch pipe desorption valve is provided on the first side-line rear branch pipe; the second desulfurization hydrogen outlet of the second desulfurization adsorption device 2 is connected to the second raw material hydrogen inlet of the second desulfurization adsorption device 2 in sequence through the second side-line front branch pipe, the first circulation main pipe, and the second side-line rear branch pipe; a second side-line front branch pipe desorption valve is provided on the second side-line front branch pipe, and a second side-line rear branch pipe desorption valve is provided on the second side-line rear branch pipe.

[0129] The first circulation main pipe is connected to a first gas circulation pump 20 and an optional first heating device 21; the heating inlet of the first heating device 21 is connected to the suction outlet of the first gas circulation pump 20, and the heating outlet of the first heating device 21 is connected to the first inlet of the raw material hydrogen of the first desulfurization adsorption device 1 via the first side line branch pipe desorption valve, and connected to the second inlet of the raw material hydrogen of the second desulfurization adsorption device 2 via the second side line branch pipe desorption valve.

[0130] Optionally, the system further includes a first feed valve 8, a first discharge valve 9, a second feed valve 10, and a second discharge valve 11; the first feed valve 8 is located on the first branch pipe for hydrogen feed, the first discharge valve 9 is located on the first branch pipe for desulfurized hydrogen discharge; the second feed valve 10 is located on the second branch pipe for hydrogen feed, and the second discharge valve 11 is located on the second branch pipe for desulfurized hydrogen discharge.

[0131] Optionally, the system also includes a first hydrogen release pipeline 23 and a first hydrogen release valve 22. The first hydrogen release valve 22 is installed on the first hydrogen release pipeline 23. The inlet end of the first hydrogen release pipeline 23 is connected to the outlet of the first branch pipe for desulfurized hydrogen discharge and the outlet of the second branch pipe for desulfurized hydrogen discharge, respectively.

[0132] Optionally, the second side-line desorption and regeneration unit includes a second circulation main pipe, a third side-line front branch pipe, a third side-line rear branch pipe, a fourth side-line front branch pipe, and a fourth side-line rear branch pipe; the first product hydrogen outlet of the first decarbonization adsorption device 3 is connected to the first desulfurization hydrogen inlet of the first decarbonization adsorption device 3 in sequence through the third side-line front branch pipe, the second circulation main pipe, and the fourth side-line rear branch pipe; the third side-line front branch pipe is equipped with a third side-line front branch pipe desorption valve, and the third side-line rear branch pipe is equipped with a third side-line rear branch pipe desorption valve; the second product hydrogen outlet of the second decarbonization adsorption device 4 is connected to the second desulfurization hydrogen inlet of the second decarbonization adsorption device 4 in sequence through the fourth side-line front branch pipe, the second circulation main pipe, and the fourth side-line rear branch pipe; the fourth side-line front branch pipe is equipped with a fourth side-line front branch pipe desorption valve, and the fourth side-line rear branch pipe is equipped with a fourth side-line rear branch pipe desorption valve.

[0133] The second circulation main pipe is connected to a second gas circulation pump 28 and an optional second heating device 29; the heating inlet of the second heating device 29 is connected to the suction outlet of the second gas circulation pump 28, and the heating outlet of the second heating device 29 is connected to the first inlet of the raw material hydrogen of the first decarbonization adsorption device 3 via the desorption valve of the third side line post branch pipe, and connected to the second inlet of the desulfurization hydrogen of the second decarbonization adsorption device 4 via the desorption valve of the fourth side line post branch pipe.

[0134] Optionally, the system further includes a third feed valve 12, a third discharge valve 13, a fourth feed valve 14, and a fourth discharge valve 15; the third feed valve 12 is located on the first branch pipe for desulfurization hydrogen feeding, the third discharge valve 13 is located on the first branch pipe for product hydrogen discharge; the fourth feed valve 14 is located on the second branch pipe for desulfurization hydrogen feeding, and the fourth discharge valve 15 is located on the second branch pipe for product hydrogen discharge.

[0135] Optionally, the system further includes a second hydrogen release pipeline 31 and a second hydrogen release valve 30. The second hydrogen release valve 30 is disposed on the second hydrogen release pipeline 31, and the inlet end of the second hydrogen release pipeline 31 is connected to the outlet of the first branch pipe for product hydrogen discharge and the outlet of the second branch pipe for product hydrogen discharge, respectively.

[0136] like Figure 2 As shown, the following describes the specific process flow of the two-stage fuel cell-grade hydrogen purification method and system provided in this disclosure:

[0137] In desulfurization unit A: the first feed valve 8 and the first discharge valve 9 are opened, and the second feed valve 10, the second discharge valve 11, the first side line front branch pipe desorption valve 16, the first side line rear branch pipe desorption valve 17, the second side line front branch pipe desorption valve 18, the second side line rear branch pipe desorption valve 19, and the first hydrogen release valve 22 are closed. The hydrogen feedstock 5 from the PSA unit enters the top of the first desulfurization adsorption unit 1 through the feedstock conveying pipeline and the first feedstock branch pipe, and flows from top to bottom through the first desulfurization adsorbent bed in the first desulfurization adsorption unit 1; then the desulfurized hydrogen 6 obtained flows out from the bottom of the first desulfurization adsorption unit 1 and enters the decarbonization unit B.

[0138] In decarbonization unit B: the third feed valve 12 and the third discharge valve 13 are opened, and the fourth feed valve 14, the fourth discharge valve 15, the third side line front branch pipe desorption valve 24, the third side line rear branch pipe desorption valve 25, the fourth side line front branch pipe desorption valve 26, the fourth side line rear branch pipe desorption valve 27, and the second hydrogen release valve 30 are closed; the desulfurized hydrogen 6 from desulfurization unit A enters the top of the first decarbonization adsorption device 3 through the desulfurized hydrogen conveying pipeline and the first desulfurized hydrogen feed branch pipe, and flows from top to bottom through the first decarbonization adsorbent bed in the first decarbonization adsorption device 3; then the resulting product hydrogen 7 flows out from the bottom of the first decarbonization adsorption device 3;

[0139] Simultaneously monitor the carbon monoxide concentration C2 and sulfide concentration C1 in the outlet hydrogen of the first decarbonization adsorption device 3 of the decarbonization unit; when C1 does not reach the first concentration threshold C 01 Furthermore, C2 did not reach the second concentration threshold C. 02 At the same time, the first desulfurization adsorption unit 1 and the first decarbonization adsorption unit 3 continue to work, and the resulting product hydrogen 7 is output through the first hydrogen discharge branch pipe and the product hydrogen output pipeline.

[0140] When C1 reaches the first concentration threshold C 01 At that time, in desulfurization unit A: immediately close the first feed valve 8 and open the second feed valve 10 and the second discharge valve 11 to stop the introduction of hydrogen raw material 5 into the first desulfurization adsorption device 1; and let the hydrogen raw material 5 enter the top of the second desulfurization adsorption device 2 through the raw material conveying pipeline and the second raw material feed branch pipe, and flow from top to bottom through the second desulfurization adsorbent bed in the second desulfurization adsorption device 2; then the desulfurized hydrogen 6 obtained flows out from the bottom of the second desulfurization adsorption device 2 and enters the decarbonization unit;

[0141] Furthermore, after stopping the introduction of hydrogen feedstock into the first desulfurization adsorption unit 1, the process also includes desorption and regeneration of the first desulfurization adsorbent within the first desulfurization adsorption unit 1. This includes: firstly, opening the first hydrogen release valve 22 to release a portion of the gas from the bottom of the first desulfurization adsorption unit 1 via the first hydrogen release pipeline 23; then closing the first hydrogen release valve 22; opening the first side line front branch desorption valve 16 and the first side line rear branch desorption valve 17; and connecting the first gas circulation pump 20 to the gas inside the first desulfurization adsorption unit 1. The first gas circulation pump 20 extracts gas from the inside of the first desulfurization adsorption device 1 and pressurizes the extracted gas. After pressurization, the gas enters the first heating device 21 for heating and temperature rise. After temperature rise, the gas returns to the inside of the first desulfurization adsorption device 1 through the first side line post branch pipe desorption valve 17, so that the first desulfurization adsorbent in the adsorption device is desorbed and regenerated under low pressure and temperature rise conditions. After the desorption and regeneration are completed, the first side line front branch pipe desorption valve 16 and the first side line rear branch pipe desorption valve 17 are closed, and the first desulfurization adsorption device 1 is ready for use.

[0142] When the outlet hydrogen gas obtained from decarbonization unit B is detected to have reached the first concentration threshold C1 again... 01 At that time, following the above process, stop introducing raw material hydrogen 5 into the second desulfurization adsorption unit, introduce raw material hydrogen into the first desulfurization adsorption unit 1, and regenerate and desorb the second desulfurization adsorbent in the second desulfurization adsorption unit 2.

[0143] When C2 reaches the second concentration threshold C 02 At that time, in the decarbonization unit B: immediately close the third feed valve 12 and open the fourth feed valve 14 and the fourth discharge valve 15 to stop the introduction of desulfurized hydrogen 6 from the desulfurization unit into the first decarbonization adsorption device 3; and introduce the desulfurized hydrogen 6 into the top of the second decarbonization adsorption device 4 through the desulfurization conveying pipeline and the second branch pipe for desulfurized hydrogen feed, where it flows from top to bottom through the second decarbonization adsorbent bed; then the resulting product hydrogen flows out from the bottom of the second decarbonization adsorption device 4.

[0144] Furthermore, after stopping the introduction of desulfurized hydrogen into the first decarbonization adsorption device 3, the process also includes desorption and regeneration of the first decarbonization adsorbent in the first decarbonization adsorption device 3, including: firstly opening the second hydrogen release valve 30, releasing part of the gas in the adsorption device from the bottom of the first decarbonization adsorption device 3 through the second hydrogen release pipeline 31, then closing the second hydrogen release valve 30, opening the desorption valve 24 of the third side line front branch and the desorption valve 25 of the third side line rear branch, and connecting the second gas circulation pump 28 to the gas inside the first decarbonization adsorption device 3. The second gas circulation pump 28 extracts the gas inside the first decarbonization adsorption device 3 and pressurizes the extracted gas. After pressurization, the gas enters the second heating device 29 for heating. After heating, the gas returns to the inside of the first decarbonization adsorption device 3 through the desorption valve of the third side line rear branch pipe, so that the first decarbonization adsorbent in the adsorption device is desorbed and regenerated under low pressure and high temperature conditions. After the desorption and regeneration are completed, the desorption valve 24 of the third side line front branch pipe and the desorption valve 25 of the third side line rear branch pipe are closed, and the first decarbonization adsorption device 3 is ready for use.

[0145] When the outlet hydrogen gas from decarbonization unit B is detected to have C2 reaching the second concentration threshold C again... 02 At that time, referring to the above process, stop introducing the desulfurized hydrogen gas 6 from the desulfurization unit into the second decarbonization adsorption device 4, and introduce the desulfurized hydrogen gas 6 into the first decarbonization adsorption device 3, and regenerate and desorb the second decarbonization adsorbent of the second decarbonization adsorption device 4.

[0146] Then, following the steps described above, the hydrogen feedstock is repeatedly fed into the first or second desulfurization adsorption unit, the desulfurized hydrogen from the desulfurization unit is repeatedly fed into the first or second decarbonization adsorption unit for operation, and the adsorbent in the stopped adsorption unit is desorbed and regenerated.

[0147] The present disclosure will be further described below with reference to embodiments and comparative examples.

[0148] It should be noted that the raw materials / reagents used in the following examples, if otherwise specified, are commercially available chemical reagents and there are no special restrictions on them.

[0149] The XRD diffractometer used in this disclosure is an XRD-6000 X-ray powder diffractometer (Shimadzu, Japan). The XRD test conditions are: Cu target, Kα rays (wavelength λ = 0.154 nm), tube voltage of 40 kV, tube current of 200 mA, and scanning speed of 10° (2q) / min.

[0150] Preparation Example 1

[0151] This preparation example is used to prepare a carbon monoxide adsorbent, specifically including:

[0152] 2g of anhydrous copper chloride, 3g of anhydrous copper acetate, and 1g of nickel citrate were dissolved in water and stirred thoroughly. The solution was then dispersed and impregnated onto 5g of high specific surface area activated carbon carrier. The rotary evaporator flask temperature was controlled at 60℃, and the evaporation was carried out at 20rpm in a water bath. The activated carbon had a specific surface area of ​​1200m². 2 The copper loading (first active component) was controlled to be 6 mmol / g, and the nickel loading (second active component) was controlled to be 1 mmol / g. The impregnated support was dried entirely at 80°C and then sintered at 260°C under inert gas protection to prepare a carbon monoxide adsorbent, denoted as sample A. The weight ratio of the first active component to the second active component was 1:0.125.

[0153] XPS characterization of the sintered product revealed that the active components included Cu and Ni; the adsorbent's adsorption capacity for carbon monoxide reached 200 mL / g; the adsorbent was columnar, 1 mm in diameter and 8 mm in length; and its BET specific surface area was 800 m² / g. 2 / g, average pore size 1nm, pore volume 0.4cm³ 3 / g.

[0154] Comparative Example 1

[0155] 225 g of anhydrous copper nitrate was dissolved in water and stirred thoroughly. The solution was then dispersed and impregnated onto 100 g of high specific surface area activated carbon support. The rotary evaporator was operated at 60 °C in a water bath at 20 rpm, with the copper loading ratio of the activated carbon controlled at 12.0 mmol / g. The impregnated support was dried entirely at 80 °C and then sintered at 180 °C under inert gas protection to prepare a carbon monoxide adsorbent, denoted as sample D-1.

[0156] Preparation Example 2

[0157] This preparation example is used to prepare the sulfide adsorbent OMS-2:

[0158] Dissolve 3.17g of potassium permanganate in 40.55g of deionized water, heat and stir to dissolve and form a potassium permanganate solution. Mix the solution with 5.78g of 50% manganese sulfate solution, add 6mL of nitric acid to adjust the pH of the solution to 1.0, stir well, and react at 130℃ for 24h.

[0159] The generated brown precipitate was filtered and washed multiple times with deionized water until the pH of the washing solution was 7. The solid product was then dried overnight at 120°C and calcined in air at 400°C for 4 hours to obtain manganese oxide molecular sieve, which was designated as desulfurization adsorbent sample B: OMS-2-Hydro.

[0160] The XRD pattern of sample B is shown below. Figure 3 As shown, from Figure 3 As can be seen from the data, sample B only shows the characteristic peaks of OMS-2.

[0161] The BET specific surface area of ​​desulfurization adsorbent sample B is 200 m². 2 / g, pore volume 0.5cm³ 3 The weight ratio of manganese to oxygen is 1.7:1. The weight ratio of manganese to oxygen was obtained from X-ray fluorescence spectroscopy analysis.

[0162] Examples 1-3 below illustrate the breakthrough performance test of desulfurization adsorbent B and decarbonization adsorbent A packed in a single fixed-bed adsorber.

[0163] In the following examples and comparative examples, the carbon monoxide concentration threshold was 0.2 ppm and the hydrogen sulfide concentration threshold was 0.004 ppm (4 ppb).

[0164] Example 1

[0165] Two mL of sulfide adsorbent B was placed in a single fixed-bed adsorber (Ta), and two mL of carbon monoxide adsorbent A was placed in another single fixed-bed adsorber (Tb). The adsorbents were activated at 300°C for 120 minutes under nitrogen protection, then cooled to room temperature. Subsequently, high-purity hydrogen gas containing 10 ppm carbon monoxide was introduced into Ta, and high-purity hydrogen gas containing 1 ppm hydrogen sulfide was introduced into Tb. The gas flow rate was controlled at 6 L / h, and the space velocity was controlled at 3000 h⁻¹. -1 The operating pressure was 2.1 MPa, the test temperature was 25℃, and the breakthrough curve of the adsorbent was tested. The packing density of the sulfide adsorbent B in Ta was 0.6 g / mL; the packing density of the carbon monoxide adsorbent A in Tb was 0.55 g / mL.

[0166] The initial concentration of carbon monoxide in the product gas was 0 ppm, and the initial concentration of hydrogen sulfide was 0 ppb. After 60 hours, the carbon monoxide concentration was higher than 0.2 ppm, and the breakthrough time of hydrogen sulfide reached 480 hours, at which point the test ended.

[0167] Example 2

[0168] Two mL of sulfide adsorbent B was placed in a single fixed-bed adsorber (Ta), and four mL of carbon monoxide adsorbent A was placed in another single fixed-bed adsorber (Tb). The adsorbents were activated at 300 °C for 120 minutes under nitrogen protection, then cooled to room temperature. High-purity hydrogen gas containing 5 ppm carbon monoxide was then introduced into Ta, and high-purity hydrogen gas containing 1 ppm hydrogen sulfide was introduced into Tb. The gas flow rate was controlled at 6 L / h, and the space velocity was 3000 h⁻¹. -1 and 1500h -1The operating pressure was 2.1 MPa, the test temperature was 45℃, and the breakthrough curve of the adsorbent was tested. The packing density of the sulfide adsorbent B in Ta was 0.55 g / mL; the packing density of the carbon monoxide adsorbent A in Tb was 0.6 g / mL.

[0169] The initial concentration of carbon monoxide in the product gas was 0 ppm, and the initial concentration of hydrogen sulfide was 0 ppb. After 180 hours, the carbon monoxide concentration was higher than 0.2 ppm, and the breakthrough time of hydrogen sulfide reached 520 hours, at which point the test ended.

[0170] Example 3

[0171] Two mL of sulfide adsorbent B was placed in a single fixed-bed adsorber (Ta), and four mL of carbon monoxide adsorbent A was placed in another single fixed-bed adsorber (Tb). The adsorbents were activated at 300°C for 120 minutes under nitrogen protection, then cooled to room temperature. High-purity hydrogen gas containing 5 ppm carbon monoxide was then introduced into Ta, and high-purity hydrogen gas containing 1 ppm hydrogen sulfide was introduced into Tb. The gas flow rate was controlled at 6 L / h, and the space velocity was 3000 h⁻¹. -1 and 1500h -1 The operating pressure was 2.1 MPa, the test temperature was 65℃, and the breakthrough curve of the adsorbent was tested. The packing density of the sulfide adsorbent B in Ta was 0.65 g / mL; the packing density of the carbon monoxide adsorbent A in Tb was also 0.65 g / mL.

[0172] The initial concentration of carbon monoxide in the product gas was 0 ppm, and the initial concentration of hydrogen sulfide was 0 ppb. After 140 hours, the carbon monoxide concentration was higher than 0.2 ppm, and the breakthrough time of hydrogen sulfide reached 600 hours, at which point the test ended.

[0173] Comparative Example 2

[0174] Two mL of sample D-1 from Comparative Example 1 was placed in a single fixed-bed adsorber and activated at 300 °C for 120 minutes under nitrogen protection. The mixture was then cooled to room temperature, and high-purity hydrogen containing 500 ppm carbon monoxide was introduced at a flow rate of 2 L / h and a space velocity of 1000 h⁻¹. -1 The operating pressure was 4.0 MPa, the test temperature was 25℃, and the breakthrough curve of the adsorbent was tested.

[0175] The initial carbon monoxide concentration in the product gas was 0 ppm. After 0.5 hours, the carbon monoxide concentration was higher than 0.2 ppm, and the test ended.

[0176] Comparative Example 3

[0177] This comparative example is used to illustrate the general technical effects of adsorbents in this field.

[0178] Two mL of iron oxide and hydrogen sulfide adsorbent was placed in a single fixed-bed adsorber (Ta), and four mL of carbon monoxide adsorbent A was placed in another single fixed-bed adsorber (Tb). The adsorbents were activated at 300 °C for 120 minutes under nitrogen protection, then cooled to room temperature. High-purity hydrogen gas containing 5 ppm carbon monoxide was then introduced into Ta, and high-purity hydrogen gas containing 1 ppm hydrogen sulfide was introduced into Tb. The gas flow rate was controlled at 6 L / h, and the space velocity was 3000 h⁻¹. -1 and 1500h -1 The operating pressure was 2.1 MPa, the test temperature was 45℃, and the breakthrough curve of the adsorbent was tested. The packing density of the iron oxide and hydrogen sulfide adsorbent in Ta was 0.65 g / mL; the packing density of the carbon monoxide adsorbent A in Tb was also 0.65 g / mL.

[0179] The initial concentration of carbon monoxide in the product gas was 0 ppm, and the initial concentration of hydrogen sulfide was 20 ppb. After 140 hours, the carbon monoxide concentration was higher than 0.2 ppm, and the hydrogen sulfide concentration did not meet the standard requirement of <4 ppb.

[0180] As can be seen from the above embodiments and comparative examples, the desulfurization adsorbent and decarbonization adsorbent provided in this disclosure have better adsorption performance and a longer adsorption cycle.

[0181] Example 4

[0182] according to Figure 2 The system shown fills each of the two fixed-bed adsorbers (Ta and Tc) connected in parallel within the desulfurization unit with 2 mL of sulfide adsorbent B, and each of the two fixed-bed adsorbers (Tb and Td) connected in parallel within the decarbonization unit with 2 mL of carbon monoxide adsorbent A. The ratio of adsorbent filling in each desulfurization fixed-bed adsorber to that in each decarbonization fixed-bed adsorber is 1:1. The system is activated at 300°C for 120 minutes under nitrogen protection, then cooled to room temperature. Subsequently, high-purity hydrogen gas containing 5 ppm carbon monoxide and 10 ppm hydrogen sulfide is introduced into the first desulfurization adsorber Ta of the desulfurization unit. The gas flow rate is controlled at 6 L / h, the operating pressure at 2.5 MPa, and the volumetric hourly space velocity at 3000 h⁻¹. -1 The adsorption temperature for Ta desulfurization is 50℃;

[0183] The obtained desulfurized hydrogen gas is further introduced into the first decarbonization adsorber Tb in the decarbonization unit. The gas flow rate in Tb is controlled at 6 L / h, the operating pressure is 2.5 MPa, and the volumetric space velocity is 3000 h⁻¹. -1 The Tb decarbonization adsorption temperature is 25℃;

[0184] After Ta is deactivated (i.e., the C1 concentration in the outlet hydrogen of the decarbonization unit reaches the first concentration threshold C), 01At that time, the raw material hydrogen was introduced into the second desulfurization adsorber Tc to continue the adsorption experiment (adsorption conditions were the same as for Ta). The Ta was then regenerated and desorbed, including: after the reactor discharged hydrogen to a pressure of 0.01 MPa, the temperature was raised to 500℃, held at that temperature for 4 hours, and then cooled to 25℃. The remaining hydrogen was discharged, and the regenerated Ta was ready for use.

[0185] After Tb is deactivated (i.e., the C2 concentration in the outlet hydrogen of the decarbonization unit reaches the second concentration threshold C), 02 At that time, desulfurized hydrogen from the desulfurization unit is introduced into the second decarbonization adsorber Td to continue the adsorption experiment (adsorption conditions are the same as Tb). Tb is then regenerated and desorbed, including: after the reactor discharges hydrogen to a pressure of 0.01 MPa, the temperature is raised to 500℃, held at that temperature for 4 hours, and then cooled to 25℃. The remaining hydrogen is discharged, and the regenerated Tb is ready for use.

[0186] The initial concentration of carbon monoxide in the product gas was 0 ppm, and the initial concentration of hydrogen sulfide was 0 ppb. After 220 hours, the carbon monoxide concentration exceeded 0.2 ppm, and the breakthrough time of hydrogen sulfide reached 1000 hours, at which point the test ended. After the Tc reactor became saturated, the gas was transferred to the Ta reactor for adsorption again; after the Td reactor became saturated, the gas was transferred to the Tb reactor for adsorption again. The breakthrough times for the second adsorption of Ta and Tb were similar to those for the first adsorption.

[0187] The packing density of the desulfurization adsorbent in the desulfurization units Ta and Tc is 1.0 g / mL; the packing density of the decarbonization adsorbent in the decarbonization units Tb and Td is 0.5 g / mL.

[0188] Example 5

[0189] The same method as in Example 4 was used, except that the adsorption process parameters were changed: the gas flow rate in Ta and Tc in the desulfurization unit was controlled at 10 L / h, and the volume hourly space velocity was controlled at 5000 h⁻¹. -1 In the decarbonization unit, the gas flow rate in Tb and Td is controlled at 10 L / h, and the space velocity is controlled at 5000 h⁻¹. -1 The remaining parameters are the same as in Example 4;

[0190] The initial concentration of carbon monoxide in the product gas was 0 ppm, and the initial concentration of hydrogen sulfide was 0 ppb. After 150 hours, the carbon monoxide concentration exceeded 0.2 ppm, and the breakthrough time of hydrogen sulfide reached 800 hours, at which point the test was completed. After the Tc reactor became saturated, the gas was transferred to the Ta reactor for adsorption again; when the Td reactor became saturated, the gas was transferred to the Tb reactor for adsorption again. The breakthrough times for the second adsorption of Ta and Tb were similar to those for the first adsorption.

[0191] Based on a comparison of Examples 4 and 5 above, it can be seen that when the volume hourly space velocity in the desulfurization unit and the decarbonization unit is 2000–4000 h⁻¹ -1 When using the desulfurization adsorbent and decarbonization adsorbent provided in this disclosure, a longer adsorption cycle can be obtained in the system provided in this disclosure.

[0192] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0193] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0194] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for purifying hydrogen in a two-stage fuel cell, characterized in that, Includes the following steps: S1. The hydrogen feedstock from the PSA unit is introduced into one of the two desulfurization adsorption devices in the desulfurization unit, where it comes into contact with the desulfurization adsorbent to adsorb sulfides and obtain desulfurized hydrogen. Then, the desulfurized hydrogen from the desulfurization unit is introduced into one of the two decarbonization adsorption devices in the decarbonization unit, where it comes into contact with the decarbonization adsorbent to adsorb carbon monoxide and obtain product hydrogen. Monitor the concentrations of sulfide C1 and carbon monoxide C2 in the hydrogen gas exiting the decarbonization unit; S2, When C1 reaches the first concentration threshold C 01 When the hydrogen feedstock is introduced into the desulfurization adsorption device in the desulfurization unit, the hydrogen feedstock is introduced into the other of the two desulfurization adsorption devices in the desulfurization unit to contact the desulfurization adsorbent for sulfide adsorption; and the desulfurization adsorbent in the desulfurization adsorption device that has stopped working is regenerated and desorbed or the desulfurization adsorption device that has stopped working is replaced with fresh desulfurization adsorbent. as well as When C2 reaches the second concentration threshold C 02 When the desulfurized hydrogen is introduced into the decarbonization adsorption device in the decarbonization unit, the desulfurized hydrogen is introduced into the other of the two decarbonization adsorption devices in the decarbonization unit to adsorb carbon monoxide and obtain product hydrogen; and the decarbonization adsorbent in the decarbonization adsorption device that has stopped working is regenerated and desorbed. S3, Repeat steps S1~S2; where C 01 The concentration is 0.003~0.004 ppm, C 02 The concentration is 0.18~0.20 ppm; The decarbonization unit includes a first decarbonization adsorption device and a second decarbonization adsorption device arranged in parallel. The method further includes: S301. Desulfurized hydrogen from the desulfurization unit is introduced into the first decarbonization adsorption device (3) and comes into contact with the first decarbonization adsorbent to perform first carbon monoxide adsorption, thereby obtaining the first product hydrogen. S302, When C2 reaches the second concentration threshold C 02 When the desulfurization hydrogen gas from the desulfurization unit is introduced into the first decarbonization adsorption device (3), the desulfurization hydrogen gas is introduced into the second decarbonization adsorption device (4) and comes into contact with the second decarbonization adsorbent to perform the second carbon monoxide adsorption, thereby obtaining the second product hydrogen gas; and the first decarbonization adsorbent is regenerated and desorbed. S303, When C2 reaches the second concentration threshold C 02 At that time, stop introducing desulfurized hydrogen from the desulfurization unit into the second decarbonization adsorption device (4), and allow the desulfurized hydrogen from the desulfurization unit to enter the first decarbonization adsorption device (3); and regenerate and desorb the second decarbonization adsorbent; S304, Repeat steps S301~S303; The first decarbonization adsorbent and the second decarbonization adsorbent are both carbon monoxide adsorbents; the carbon monoxide adsorbent includes a carrier and a first active component and a second active component loaded on the carrier; the first active component includes a monovalent copper compound and / or a divalent copper compound; the second active component includes a nickel compound; based on the total mass of the carbon monoxide adsorbent, the content of the first active component is 25-50% by weight; the content of the second active component is 3-10% by weight; the weight ratio of the first active component to the second active component is (0.4-1.2):(0.075-0.15).

2. The method according to claim 1, characterized in that, The desulfurization unit includes a first desulfurization adsorption device and a second desulfurization adsorption device arranged in parallel. The method further includes: S201. Hydrogen raw material is introduced into the first desulfurization adsorption device (1) and comes into contact with the first desulfurization adsorbent to perform first sulfide adsorption, thereby obtaining first desulfurized hydrogen gas; then the first desulfurized hydrogen gas is introduced into the decarbonization unit. S202, When C1 reaches the first concentration threshold C 01 When the hydrogen raw material is introduced into the first desulfurization adsorption device (1), the hydrogen raw material is introduced into the second desulfurization adsorption device (2) and comes into contact with the second desulfurization adsorbent to perform second sulfide adsorption, thereby obtaining second desulfurized hydrogen; then the second desulfurized hydrogen is introduced into the decarbonization unit; and the first desulfurization adsorbent is regenerated and desorbed. S203, When C1 reaches the first concentration threshold C 01 When the hydrogen raw material is introduced into the second desulfurization adsorption device (2), the hydrogen raw material is introduced into the first desulfurization adsorption device (1); and the second desulfurization adsorbent is regenerated and desorbed. S204. Repeat steps S201 to S203.

3. The method according to claim 2, characterized in that, The regeneration and desorption described in step S202 includes the following steps: Extract the gas from the first desulfurization adsorption device (1) and return the gas to the first desulfurization adsorption device (1) through the first external pipeline. The regeneration desorption described in step S203 includes the following steps: extracting the gas from the second desulfurization adsorption device (2) and returning the gas to the second desulfurization adsorption device (2) through the second external pipeline.

4. The method according to claim 3, characterized in that, The regeneration desorption described in step S202 further includes: extracting the gas from the first desulfurization adsorption device and heating it, so that the heated gas is returned to the first desulfurization adsorption device. The regeneration desorption described in step S203 further includes: extracting the gas from the second desulfurization adsorption device (2) and heating it so that the heated gas is returned to the second desulfurization adsorption device.

5. The method according to claim 1, characterized in that, The regeneration and desorption described in step S302 includes the following steps: Extract the gas from the first decarbonization adsorption device (3) and return the gas to the first decarbonization adsorption device (3) through the third external pipeline. The regeneration and desorption described in step S303 includes the following steps: extracting the gas from the second decarbonization adsorption device (4) and returning the gas to the second decarbonization adsorption device (4) through the fourth external pipeline.

6. The method according to claim 5, characterized in that, The regeneration desorption described in step S302 further includes: extracting the gas from the first decarbonization adsorption device (3) and heating it so that the heated gas is returned to the first decarbonization adsorption device (3). The regeneration desorption described in step S303 further includes: extracting the gas from the second decarbonization adsorption device (4) and heating it so that the heated gas is returned to the second decarbonization adsorption device (4).

7. The method according to claim 1, characterized in that, The method also includes: The sulfide concentration C1 and carbon monoxide concentration C2 of the hydrogen outlet gas from the decarbonization unit are detected respectively. When C1 is equal to the first concentration threshold C... 01 Below, and C2 is the second concentration threshold C. 02 In the following case, the hydrogen gas exiting the decarbonization unit is output as product hydrogen gas.

8. The method according to claim 2, characterized in that, The first desulfurization adsorbent and the second desulfurization adsorbent are both sulfide adsorbents, and the sulfide adsorbents include manganese oxide molecular sieves.

9. The method according to claim 8, characterized in that, The manganese oxide molecules are selected from one or more of the following: sodium manganite, bosellite, hydrous manganite, barium manganite, potassium manganite, and calcium manganite.

10. The method according to claim 8, characterized in that, The BET specific surface area of ​​the manganese oxide molecular sieve is 50~400 m². 2 / g, pore volume 0.3~1 cm³ 3 / g, the weight ratio of manganese and oxygen is 1.5~2.5:

1.

11. The method according to claim 8, characterized in that, The sulfide adsorbent is prepared by a method comprising the following steps: A hydrothermal synthesis reaction is carried out by an aqueous solution containing oxidized manganese compounds and reduced manganese compounds. The solid product is collected, washed, dried, and calcined.

12. The method according to claim 11, characterized in that, The oxidized manganese compound is selected from one or more of potassium permanganate, potassium manganate, and sodium permanganate, and the reduced manganese compound is selected from one or more of manganese sulfate, manganese nitrate, manganese acetate, and manganese chloride.

13. The method according to claim 11, characterized in that, The molar ratio of the oxidized manganese compound to the reduced manganese compound is (0.2~3):

1.

14. The method according to claim 11, characterized in that, The hydrothermal synthesis reaction is carried out at a temperature of 60~200℃ for a reaction time of 1~36h.

15. The method according to claim 11, characterized in that, The drying temperature is 80~350℃ and the time is 1~24h, and the calcination temperature is 200~900℃ and the time is 0.5~12h.

16. The method according to claim 11, characterized in that, Prior to the hydrothermal synthesis reaction, acid is added to the aqueous solution to adjust the pH value of the aqueous solution to 0.2-3.

17. The method according to claim 1, characterized in that, In the carbon monoxide adsorbent, the carrier includes activated carbon, and the specific surface area of ​​the activated carbon is 400~2000 m². 2 / g.

18. The method according to claim 1, characterized in that, The first active component is selected from one or more of cuprous oxide, copper oxide, cuprous chloride, copper chloride, cuprous nitrate, copper nitrate, cuprous sulfate, copper acetate, copper formate, and copper sulfate; the second active component is selected from one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel citrate.

19. The method according to claim 1, characterized in that, The carbon monoxide adsorbent may be in any one of the following shapes: spherical, columnar, or sheet-like. When the carbon monoxide adsorbent is in the form of spherical particles, the particle size is 1-3 mm; when the carbon monoxide adsorbent is in the form of columns, the cross-sectional diameter is 1-3 mm and the length is 5-20 mm; when the carbon monoxide adsorbent is in the form of flakes, the thickness is 0.5-2 mm.

20. The method according to claim 1, characterized in that, The BET specific surface area of ​​the carbon monoxide adsorbent is 300~1200 m². 2 / g, average pore size 0.3~2nm, pore volume 0.25~0.6cm³ 3 / g.

21. The method according to claim 1, characterized in that, The carbon monoxide adsorbent is prepared using the following steps: a. Mix the first active component precursor and the second active component precursor with water to obtain a precursor solution; b. Immerse the carrier in the precursor solution to obtain a mixture; c. Dry and calcine the mixture.

22. The method according to claim 21, characterized in that, In step a, the first active component precursor is a water-soluble copper salt; the second active component precursor is a water-soluble nickel salt; and the BET specific surface area of ​​the carrier is 300~2000 m². 2 / g, pore volume 0.5~0.8cm³ 3 / g; In step b, the immersion temperature is 25~70℃, and the immersion time is 0.5~4h; In step c, the drying temperature is 60~110℃ and the drying time is 2~8h; the calcination temperature is 240~300℃ and the calcination time is 3~6h, and the calcination atmosphere is argon or nitrogen.

23. The method according to claim 21, characterized in that, The first active component precursor is selected from one or more of copper chloride, copper nitrate, copper acetate, copper formate, and copper sulfate; The second active component precursor is selected from one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel citrate.

24. The method according to claim 1, characterized in that, The adsorption operation pressure for the sulfide adsorption in the desulfurization unit is the same as the pressure of the hydrogen feedstock, which is 1.5~6.0 MPa.

25. The method according to claim 24, characterized in that, The conditions for sulfide adsorption in the desulfurization unit include: an adsorption temperature of 20~150℃ and a volume hourly space velocity of 1000~9000 h⁻¹. -1 .

26. The method according to claim 25, characterized in that, The conditions for sulfide adsorption in the desulfurization unit include: an adsorption temperature of 80~120℃ and a volume hourly space velocity of 2000~4000 h⁻¹. -1 .

27. The method according to claim 24, characterized in that, The packing density of the naturally accumulated sulfide adsorbent in the two desulfurization adsorption devices in the desulfurization unit is independently 0.4~1.0 g / mL.

28. The method according to claim 27, characterized in that, The packing density of the naturally accumulated sulfide adsorbent in the two desulfurization adsorption devices in the desulfurization unit is independently 0.5~0.7g / mL.

29. The method according to claim 1, characterized in that, The conditions for carbon monoxide adsorption in the decarbonization unit include: an operating pressure of 1.5~6.0 MPa, an adsorption temperature of 10~60℃, and a volume hourly space velocity of 1000~9000 h⁻¹. -1 .

30. The method according to claim 29, characterized in that, The conditions for carbon monoxide adsorption in the decarbonization unit include: an adsorption temperature of 10~40℃ and a volume hourly space velocity of 2000~4000 h⁻¹. -1 .

31. The method according to claim 29, characterized in that, The packing density of the naturally accumulated carbon monoxide adsorbent in the two decarbonization adsorption devices in the decarbonization unit is independently 0.4~0.8 g / mL.

32. The method according to claim 31, characterized in that, The packing density of the naturally accumulated carbon monoxide adsorbent in the two decarbonization adsorption devices in the decarbonization unit is independently 0.5~0.7 g / mL.

33. The method according to claim 29, characterized in that, The weight ratio of the desulfurization adsorbent in one desulfurization adsorption device in the desulfurization unit to the decarbonization adsorption device in one decarbonization unit is 0.8~1.2:

1.

34. The method according to claim 29, characterized in that, The concentration of carbon monoxide in the hydrogen feedstock is 1-500 ppm, and the concentration of total sulfide content is 1-50 ppm, wherein the sulfides include at least one of hydrogen sulfide and carbonyl sulfide.

35. The method according to claim 1, characterized in that, In step S2, during the desorption and regeneration process of the desulfurization adsorption unit, the gas pressure inside the desulfurization adsorption unit is 0.01~2.0 MPa, the temperature is 300~500℃, and the desorption and regeneration time is 2~8h. During the desorption and regeneration process of the decarbonization adsorption device, the gas pressure inside the device is 0.01~2.0 MPa, the temperature is 80~200℃, and the desorption and regeneration time is 2~8h.

36. A system for purifying hydrogen in a two-stage fuel cell stage as described in claim 1, characterized in that, Along the direction of the hydrogen feedstock flow, it includes a desulfurization adsorption unit and a decarbonization adsorption unit in sequence; The desulfurization unit includes: Two desulfurization adsorption units are connected in parallel. Each desulfurization adsorption unit includes a desulfurization adsorbent bed and a sulfide detector. The sulfide detector is used to detect the sulfide concentration of hydrogen gas at the unit outlet. The first switching control device is used to control the alternating entry of hydrogen feedstock into the two desulfurization adsorption units based on the sulfide concentration of the outlet hydrogen. The decarbonization unit includes: Two decarbonization adsorption units are connected in parallel. Each unit contains a decarbonization adsorbent bed and a carbon monoxide detector, wherein the carbon monoxide detector is used to detect the carbon monoxide concentration in the hydrogen gas at the unit outlet. The second switching control device is used to control the alternating entry of hydrogen from the desulfurization adsorption unit into the two decarbonization adsorption devices based on the carbon monoxide concentration of the outlet hydrogen.

37. The system according to claim 36, characterized in that, The system also includes a first side-line desorption and regeneration unit, a second side-line desorption and regeneration unit, a raw material conveying pipeline, and a product hydrogen pipeline; the desulfurization adsorption unit includes a raw material hydrogen inlet and a desulfurization hydrogen outlet, and the decarbonization adsorption unit includes a desulfurization hydrogen inlet and a product hydrogen outlet; The inlet end of the raw material conveying pipeline is connected to the hydrogen raw material processed by the PSA unit, and the outlet end of the raw material conveying pipeline is connected to the raw material hydrogen inlet of the desulfurization adsorption unit; the desulfurization hydrogen outlet of the desulfurization adsorption unit is connected to the desulfurization hydrogen inlet of the decarbonization unit. The inlet and outlet of each desulfurization adsorption device in the desulfurization unit are respectively connected to the first side-line desorption and regeneration unit; the inlet and outlet of each decarbonization adsorption device in the decarbonization unit are respectively connected to the second side-line desorption and regeneration unit.

38. The system according to claim 37, characterized in that, The desulfurization unit includes a first desulfurization adsorption device (1) and a second desulfurization adsorption device (2) arranged in parallel; the system also includes a first branch pipe for raw material feeding, a first branch pipe for desulfurized hydrogen discharge, a second branch pipe for raw material feeding, a second branch pipe for desulfurized hydrogen discharge, and a desulfurized hydrogen conveying pipeline. The outlet end of the raw material conveying pipeline is connected to the inlet end of the first raw material feeding branch pipe and the inlet end of the second raw material feeding branch pipe, respectively; and the inlet end of the first raw material feeding branch pipe and the inlet end of the second raw material feeding branch pipe form the raw material hydrogen inlet of the desulfurization unit. The first desulfurization adsorption device (1) is provided with a first raw material hydrogen inlet and a first desulfurized hydrogen outlet; a first desulfurization adsorbent bed is provided between the first raw material hydrogen inlet and the first hydrogen outlet; the first raw material hydrogen inlet is connected to the outlet end of the first raw material feed branch pipe for introducing hydrogen raw material (5) processed by the PSA device into the first desulfurization adsorption device (1); the first desulfurized hydrogen outlet is connected to the inlet end of the first desulfurized hydrogen outlet branch pipe; The second desulfurization adsorption device (2) is provided with a second raw material hydrogen inlet and a second desulfurized hydrogen outlet; a second desulfurization adsorbent bed is provided between the second raw material hydrogen inlet and the second hydrogen outlet; the second raw material hydrogen inlet is connected to the outlet end of the second raw material feed branch pipe for introducing hydrogen raw material (5) processed by the PSA device into the second desulfurization adsorption device (2); the second desulfurized hydrogen outlet is connected to the inlet end of the second desulfurized hydrogen outlet branch pipe; The outlet of the first branch pipe for desulfurized hydrogen discharge and the outlet of the second branch pipe for desulfurized hydrogen discharge form the desulfurized hydrogen outlet of the desulfurization unit, and are respectively connected to the inlet end of the desulfurized hydrogen conveying pipeline. The first inlet of raw hydrogen and the first outlet of desulfurized hydrogen of the first desulfurization adsorption device (1) are respectively connected to the first side-line desorption and regeneration unit; the second inlet of raw hydrogen and the second outlet of desulfurized hydrogen of the second desulfurization adsorption device (2) are respectively connected to the first side-line desorption and regeneration unit. The decarbonization unit includes two parallel first decarbonization adsorption devices (3) and second decarbonization adsorption devices (4); the system also includes a first branch pipe for desulfurization hydrogen feed, a first branch pipe for product hydrogen discharge, a second branch pipe for desulfurization hydrogen feed, and a second branch pipe for product hydrogen discharge. The inlet ends of the first and second desulfurization hydrogen feed pipes are respectively connected to the outlet end of the desulfurization hydrogen conveying pipeline, and the inlet ends of the first and second desulfurization hydrogen feed pipes form the desulfurization hydrogen inlet of the decarbonization unit. The first decarbonization adsorption device (3) is provided with a first desulfurization hydrogen inlet and a first product hydrogen outlet; a first decarbonization adsorbent bed is provided between the first desulfurization hydrogen inlet and the first product hydrogen outlet; the first desulfurization hydrogen inlet is connected to the outlet end of the first desulfurization hydrogen feed branch pipe for introducing desulfurization hydrogen from the desulfurization unit into the first decarbonization adsorption device (3); the first product hydrogen outlet is connected to the inlet end of the first product hydrogen outlet branch pipe; The second decarbonization adsorption device (4) is provided with a second desulfurization hydrogen inlet and a second product hydrogen outlet; a second decarbonization adsorbent bed is provided between the second desulfurization hydrogen inlet and the second product hydrogen outlet; the second desulfurization hydrogen inlet is connected to the outlet end of the second branch pipe for feeding desulfurization hydrogen to introduce desulfurization hydrogen from the desulfurization unit into the second decarbonization adsorption device (4); the second product hydrogen outlet is connected to the inlet end of the second branch pipe for discharging product hydrogen. The first inlet of desulfurized hydrogen and the outlet of first product hydrogen of the first decarbonization adsorption device (3) are respectively connected to the second side-line desorption and regeneration unit; the second inlet of desulfurized hydrogen and the outlet of second product hydrogen of the second decarbonization adsorption device (4) are respectively connected to the second side-line desorption and regeneration unit.

39. The system according to claim 38, characterized in that, The first side-line desorption and regeneration unit includes a first circulation main pipe, a first side-line front branch pipe, a first side-line rear branch pipe, a second side-line front branch pipe, and a second side-line rear branch pipe; the first desulfurization hydrogen outlet of the first desulfurization adsorption device (1) is connected to the first raw material hydrogen inlet of the first desulfurization adsorption device (1) in sequence through the first side-line front branch pipe, the first circulation main pipe, and the first side-line rear branch pipe; the first side-line front branch pipe is equipped with a first side-line front branch pipe desorption valve; the first side-line rear branch pipe is equipped with a first side-line rear branch pipe desorption valve; the second desulfurization hydrogen outlet of the second desulfurization adsorption device (2) is connected to the second raw material hydrogen inlet of the second desulfurization adsorption device (2) in sequence through the second side-line front branch pipe, the first circulation main pipe, and the second side-line rear branch pipe; the second side-line front branch pipe is equipped with a second side-line front branch pipe desorption valve; the second side-line rear branch pipe is equipped with a second side-line rear branch pipe desorption valve. The first circulation main pipe is connected to a first gas circulation pump (20) and a first heating device (21); the heating inlet of the first heating device (21) is connected to the suction outlet of the first gas circulation pump (20), and the heating outlet of the first heating device (21) is connected to the first raw material hydrogen inlet of the first desulfurization adsorption device (1) via the first side line back branch desorption valve and to the second raw material hydrogen inlet of the second desulfurization adsorption device (2) via the second side line back branch desorption valve.

40. The system according to claim 39, characterized in that, The system also includes a first feed valve (8), a first discharge valve (9), a second feed valve (10), and a second discharge valve (11); the first feed valve (8) is located on the first branch pipe for feeding hydrogen raw materials, and the first discharge valve (9) is located on the first branch pipe for discharging desulfurized hydrogen; the second feed valve (10) is located on the second branch pipe for feeding hydrogen raw materials, and the second discharge valve (11) is located on the second branch pipe for discharging desulfurized hydrogen.

41. The system according to claim 40, characterized in that, The system also includes a first hydrogen release pipeline (23) and a first hydrogen release valve (22). The first hydrogen release valve (22) is located on the first hydrogen release pipeline (23). The inlet end of the first hydrogen release pipeline (23) is connected to the outlet of the first branch pipe for desulfurized hydrogen discharge and the outlet of the second branch pipe for desulfurized hydrogen discharge, respectively.

42. The system according to claim 41, characterized in that, The second side-line desorption and regeneration unit includes a second circulation main pipe, a third side-line front branch pipe, a third side-line rear branch pipe, a fourth side-line front branch pipe, and a fourth side-line rear branch pipe; the first product hydrogen outlet of the first decarbonization adsorption device (3) is connected to the first desulfurization hydrogen inlet of the first decarbonization adsorption device (3) in sequence through the third side-line front branch pipe, the second circulation main pipe, and the third side-line rear branch pipe; the third side-line front branch pipe is equipped with a third side-line front branch pipe desorption valve; the third side-line rear branch pipe is equipped with a third side-line rear branch pipe desorption valve; the second product hydrogen outlet of the second decarbonization adsorption device (4) is connected to the second desulfurization hydrogen inlet of the second decarbonization adsorption device (4) in sequence through the fourth side-line front branch pipe, the second circulation main pipe, and the fourth side-line rear branch pipe; the fourth side-line front branch pipe is equipped with a fourth side-line front branch pipe desorption valve; the fourth side-line rear branch pipe is equipped with a fourth side-line rear branch pipe desorption valve. The second circulation main pipe is connected to a second gas circulation pump (28) and a second heating device (29); the heating inlet of the second heating device (29) is connected to the suction outlet of the second gas circulation pump (28), and the heating outlet of the second heating device (29) is connected to the first raw material hydrogen inlet of the first decarbonization adsorption device (3) via the desorption valve of the third side line branch pipe, and connected to the second desulfurization hydrogen inlet of the second decarbonization adsorption device (4) via the desorption valve of the fourth side line branch pipe.

43. The system according to claim 42, characterized in that, The system also includes a third feed valve (12), a third discharge valve (13), a fourth feed valve (14), and a fourth discharge valve (15); the third feed valve (12) is located on the first branch pipe for feeding desulfurized hydrogen, the third discharge valve (13) is located on the first branch pipe for discharging product hydrogen; the fourth feed valve (14) is located on the second branch pipe for feeding desulfurized hydrogen, and the fourth discharge valve (15) is located on the second branch pipe for discharging product hydrogen.

44. The system according to claim 43, characterized in that, The system also includes a second hydrogen release pipeline (31) and a second hydrogen release valve (30). The second hydrogen release valve (30) is located on the second hydrogen release pipeline (31). The inlet end of the second hydrogen release pipeline (31) is connected to the outlet of the first branch pipe for product hydrogen discharge and the outlet of the second branch pipe for product hydrogen discharge, respectively.

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