A method and system for deep removal of trace carbon monoxide from hydrogen

Abstract

The present disclosure relates to a method and system for deep removal of trace carbon monoxide in hydrogen. Two selective adsorption devices are used, when one of the selective adsorption devices is in an adsorption state, the other is in an adsorbent desorption regeneration or standby state; and in the adsorption state of the selective adsorption device, the carbon monoxide concentration of hydrogen at the outlet of the adsorption device is monitored, when the concentration threshold is reached, the other adsorption device is immediately replaced for adsorption, and the adsorbent in the adsorption device is desorbed and regenerated. The present disclosure can effectively adsorb CO without continuous pressure swing adsorption during operation, the single adsorption period is long; improve the overall yield of hydrogen, realize the ultra-deep removal of CO, and produce fuel cell grade hydrogen.

Description

Technical Field

[0001] The present disclosure relates to the field of hydrogen fuel cells, and in particular, to a method and system for deeply removing trace carbon monoxide from hydrogen. Background Art

[0002] The supply of hydrogen sources is a crucial factor influencing the industrial development 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-product gas. Industrial hydrogen standards differ from fuel cell standards. The recently promulgated GB / T 37244-2018, "Proton Exchange Membrane Fuel Cell Vehicle Fuel - Hydrogen," sets clear requirements for hydrogen. While the purity requirement for fuel cell-grade hydrogen is no longer stringent (>99.97% is sufficient), trace impurities such as CO and H2S are strictly controlled. Hydrogen production from fossil fuels is the primary method for obtaining industrial hydrogen in the petrochemical industry. These feedstocks typically contain small amounts of carbon monoxide during the hydrogen production process, an impurity that can severely deactivate platinum electrode catalysts. The GB / T 37244-2018 standard requires a concentration of less than 200 ppb.

[0003] The main methods for separating carbon monoxide from mixed gases to produce pure gas include cryogenics, solvent absorption, temperature swing adsorption, and pressure swing adsorption. Pressure swing adsorption (PSA) technology was industrialized in the mid-20th century and is now widely used to separate and purify mixed gases such as carbon monoxide, hydrogen, nitrogen, carbon dioxide, and methane. The PSA process relies on the principle of adsorption of the separated components by an adsorbent (commonly used adsorbents include molecular sieves, activated carbon, silica gel, and activated alumina) under high pressure and desorption under low pressure, achieving separation through repeated cycles of adsorption and desorption. While PSA can achieve hydrogen purities of 99.9% or higher, it cannot guarantee CO concentrations below 0.2 ppm. Some gas supply companies can only supply pure hydrogen (99.99%) or high-purity hydrogen (99.999%). Therefore, although the PSA process is mature, it suffers from high energy consumption, large footprint and investment requirements, low hydrogen yields, and the economical cost of retrofitting existing PSA equipment. CN110682803A discloses a hydrogen quality assurance system for fuel cell vehicles. In addition to two adsorbers, the patent also includes a reactor for hydrogen removal. The adsorbents in the adsorbers are primarily conventional activated carbon, molecular sieves, and other materials. During operation, a pressure swing adsorption cycle is performed within the two reactors, with the adsorption pressure controlled at 10-30 MPa. However, this method requires cyclic pressure swing adsorption and desorption within the two reactors within a relatively short period, which places high demands on the process, complicates the control system, and can easily damage the device.

[0004] In order to achieve efficient removal of trace carbon monoxide in hydrogen, a simple and efficient method is needed to ensure the quality of hydrogen. Summary of the Invention

[0005] The purpose of the present disclosure is to provide a method and system for deep removal of trace carbon monoxide in hydrogen, which achieves efficient removal of trace carbon monoxide in hydrogen raw materials from a PSA device, with a simpler process and higher efficiency.

[0006] In order to achieve the above object, the present disclosure provides a first aspect of a method for deep removal of trace carbon monoxide from hydrogen, comprising the following steps:

[0007] S1, allowing the hydrogen feed from the PSA unit to enter a first selective adsorption unit, contacting it with a first selective adsorbent to perform a first adsorption of carbon monoxide to obtain a first hydrogen product; monitoring the carbon monoxide concentration C1 in the outlet hydrogen of the first selective adsorption unit;

[0008] S2. When C1 reaches a concentration threshold C0, stop feeding the hydrogen raw material into the first selective adsorption device;

[0009] and allowing the hydrogen feedstock to enter a second selective adsorption device, contact with a second selective adsorbent to perform a second adsorption of carbon monoxide, and obtain a second product hydrogen; monitoring the carbon monoxide concentration C2 in the outlet hydrogen of the second selective adsorption device and regenerating and desorbing the first selective adsorbent in the first selective adsorption device;

[0010] S3. When C2 reaches the concentration threshold C0, stop feeding the hydrogen feedstock into the second selective adsorption device, allow the hydrogen feedstock to enter the first selective adsorption device and regenerate and desorb the second selective adsorbent in the second selective adsorption device; S4. Repeat steps S1 to S3; wherein C0 is 0.18 to 0.20 ppm.

[0011] Optionally, the regeneration and desorption in step S2 includes the following steps:

[0012] Extracting the gas in the first selective adsorption device and returning the gas to the first selective adsorption device through a first external pipeline; preferably, the method further comprises: extracting the gas in the first selective adsorption device and heating it, and returning the heated gas to the first selective adsorption device; the regeneration and desorption described in step S3 comprises the following steps: extracting the gas in the second selective adsorption device and returning the gas to the second selective adsorption device through a second external pipeline; preferably, the method further comprises: extracting the gas in the second selective adsorption device and heating it, and returning the heated gas to the second selective adsorption device.

[0013] Optionally, the method further includes: detecting the carbon monoxide concentration C1 of the outlet hydrogen of the first selective adsorption device by using gas chromatography, and when C1 is below the concentration threshold C0, outputting the outlet hydrogen of the first selective adsorption device as the first product hydrogen; and detecting the carbon monoxide concentration C2 of the outlet hydrogen of the second selective adsorption device by using gas chromatography, and when C2 is below the concentration threshold C0, outputting the outlet hydrogen of the second selective adsorption device as the second product hydrogen.

[0014] Optionally, the first selective adsorbent and the second selective adsorbent are respectively carbon monoxide adsorbents; the carbon monoxide adsorbent comprises a carrier and a first active component and a second active component supported on the carrier; the first active component comprises a monovalent copper compound and / or a divalent copper compound; the second active component comprises a nickel compound; the carrier comprises activated carbon, and the specific surface area of ​​the activated carbon is 400 to 2000 m 2 / g Optionally, the first active component is selected from one or more of cuprous oxide, cupric oxide, cuprous chloride, cupric chloride, cuprous nitrate, cupric nitrate, cuprous sulfate, cupric 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 weight %; the content of the second active component is 3-10 weight %; the first active component and the second active component are The weight ratio of the components is (0.4-1.2): (0.075-0.15); preferably, the shape of the carbon monoxide adsorbent includes sphere, column, and sheet; the carbon monoxide adsorbent is a spherical particle with a particle size of 1 to 3 mm; the carbon monoxide adsorbent is a column with a cross-sectional diameter of 1 to 3 mm and a length of 5 to 20 mm; the carbon monoxide adsorbent is a sheet with a thickness of 0.5 to 2 mm; preferably, the BET specific surface area of ​​the carbon monoxide adsorbent is 300 to 1200 m 2 / g, average pore diameter of 0.3-2nm, pore volume of 0.25-0.6cm 3 / g.

[0015] Optionally, the carbon monoxide adsorbent is prepared by the following steps: a. mixing a first active component precursor and a second active component precursor with water to obtain a precursor solution; b. immersing the carrier in the precursor solution to obtain a mixed material; c. drying and calcining the mixed material.

[0016] Optionally, in step a, the first active component precursor is a water-soluble copper salt, preferably one or more selected from copper chloride, copper nitrate, copper acetate, copper formate, and copper sulfate; the second active component precursor is a water-soluble nickel salt, preferably one or more selected from nickel sulfate, nickel nitrate, nickel acetate, and nickel citrate; the BET specific surface area of ​​the carrier is 300 to 2000 m 2 / g, pore volume 0.5~0.8cm 3 / g; impregnation temperature 25 ~ 70 ℃, impregnation time 0.5 ~ 4h; step c, drying temperature 60 ~ 110 ℃, drying time 2 ~ 8h; calcination temperature 240 ~ 300 ℃, calcination time 3 ~ 6h, calcination atmosphere is argon or nitrogen.

[0017] Optionally, during the first carbon monoxide adsorption process, the adsorption operating pressures of the first selective adsorption device and the second selective adsorption device are respectively the same as the pressure of the hydrogen feedstock, and the pressure of the hydrogen feedstock (12) is 1.5 to 6.0 MPa;

[0018] Optionally, during the first carbon monoxide adsorption and the second carbon monoxide adsorption process, the adsorption temperature in the first selective adsorption device and the second selective adsorption device is independently 10 to 60°C, preferably 10 to 45°C, and the volume space velocity in the first selective adsorption device and the second selective adsorption device is independently 1000 to 9000 h -1 , preferably 2000~4000h -1 ; Optionally, the packing density of the naturally accumulated adsorbent in the first selective adsorption device and the second selective adsorption device is independently 0.4 to 0.8 g / mL, preferably 0.5 to 0.7 g / mL; Optionally, the concentration of carbon monoxide in the hydrogen raw material is 1 to 500 ppm.

[0019] Optionally, during the desorption regeneration process of step S2, the gas pressure in the first selective adsorption device is 0.1~2.0MPa, the temperature is 80~200℃, and the desorption regeneration time is 2~8h; during the desorption regeneration process of step S3, the gas pressure in the second selective adsorption device is 0.1~2.0MPa, the temperature is 80~200℃, and the desorption regeneration time is 2~8h.

[0020] A second aspect of the present disclosure provides a system for deeply removing trace carbon monoxide from hydrogen, comprising: two selective adsorption devices arranged in parallel, each of the selective adsorption devices comprising a selective adsorbent bed and a carbon monoxide detector, the carbon monoxide detector being used to detect the carbon monoxide concentration of hydrogen at the outlet of the device; and a switching control device for controlling the hydrogen feed to alternately enter the two selective adsorption devices according to the carbon monoxide concentration of the outlet hydrogen.

[0021] Optionally, the system includes a first selective adsorption device, a second selective adsorption device, a raw material delivery pipeline, a first raw material feed branch, a first hydrogen discharge branch, a second raw material feed branch, a second hydrogen discharge branch, a fuel cell-grade hydrogen output pipeline and a side line desorption regeneration unit; the inlet end of the raw material delivery pipeline is connected to the hydrogen treated by the PSA device, and the outlet end of the raw material delivery pipeline is respectively connected to the inlet end of the first raw material feed branch and the inlet end of the second raw material feed branch; the outlet end of the first hydrogen discharge branch and the outlet end of the second hydrogen discharge branch are respectively connected to the inlet end of the fuel cell-grade hydrogen output pipeline; the first selective adsorption device is provided with a first hydrogen raw material inlet and a first hydrogen discharge port; a first selective adsorption device is provided between the first hydrogen raw material inlet and the first hydrogen discharge port. adsorbent; the first inlet of the hydrogen raw material is connected to the outlet end of the first branch pipe of the raw material feed for introducing the hydrogen treated by the PSA device into the first selective adsorption device; the second selective adsorption device is provided with a second inlet of the hydrogen raw material and a second hydrogen outlet; a second selective adsorbent is provided between the second inlet of the hydrogen raw material and the second hydrogen outlet; the second inlet of the hydrogen raw material is connected to the outlet end of the second branch pipe of the raw material feed for introducing the hydrogen treated by the PSA device into the second selective adsorption device; the first inlet of the hydrogen raw material and the first hydrogen outlet of the first selective adsorption device are respectively connected to the side desorption regeneration unit; the second inlet of the hydrogen raw material and the second hydrogen outlet of the second selective adsorption device are respectively connected to the side desorption regeneration unit.

[0022] Optionally, the side desorption regeneration unit includes a 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 hydrogen outlet of the first selective adsorption device is connected to the first hydrogen raw material inlet of the first selective adsorption device in sequence through the first side line front branch pipe, the circulation main pipe and the first side line rear branch pipe, the first side line front branch pipe is provided with a first side line front branch pipe desorption valve, the first side line rear branch pipe is provided with a first side line rear branch pipe desorption valve, the second hydrogen outlet of the second selective adsorption device is connected to the second hydrogen raw material second inlet of the second selective adsorption device in sequence through the second side line front branch pipe, the circulation main pipe and the second side line rear branch pipe, A second side line front branch pipe is provided with a second side line front branch pipe desorption valve, and a second side line rear branch pipe is provided with a second side line rear branch pipe desorption valve; a gas circulation pump and an optional heating device are connected to the circulation main pipe; the heating inlet of the heating device is connected to the suction outlet of the gas circulation pump, and the heating outlet of the heating device is respectively connected to the first side line rear branch pipe desorption valve and the second inlet of the hydrogen raw material of the second selective adsorption device via the second side line rear branch pipe desorption valve; optionally, the system also includes a hydrogen release pipeline and a hydrogen release valve, the hydrogen release valve is provided on the hydrogen release pipeline, and the inlet end of the hydrogen release pipeline is respectively connected to the outlet end of the first discharge valve and the outlet end of the second discharge valve.

[0023] Optionally, the system has a first working state and a second working state; in the first working state: open the first feed valve and the first discharge valve, and close the second feed valve, the second discharge valve, the first side line front branch desorption valve, the first side line rear branch desorption valve, the second side line front branch desorption valve, the second side line rear branch desorption valve and the hydrogen release valve, so that the hydrogen raw material enters the first selective adsorption device through the first feed valve for the first adsorption of carbon monoxide; and the obtained first product hydrogen is output through the first discharge valve and the product hydrogen output pipeline; in the second working state: close the first feed valve, open the second feed valve and the second discharge valve, so that the hydrogen raw material enters the second selective adsorption device through the second feed valve for the second adsorption of carbon monoxide; and the obtained second product hydrogen is output through the second discharge valve and the product hydrogen output pipeline.

[0024] Optionally, the first working state also includes: opening the second side line front branch desorption valve and the second side line rear branch desorption valve, and the gas circulation pump is connected to the gas in the second selective adsorption device, so that the gas in the second selective adsorption device is circulated in sequence through the second discharge valve, the second side line front branch desorption valve, the gas circulation pump and the second side line rear branch desorption valve; the second working state also includes: opening the first side line front branch desorption valve and the first side line rear branch desorption valve, and the gas circulation pump is connected to the gas inside the first selective adsorption device, so that the gas in the first selective adsorption device is circulated in sequence through the first discharge valve, the first side line front branch desorption valve, the gas circulation pump and the first side line rear branch desorption valve.

[0025] Through the above technical solution, the present disclosure provides a method and system for deep removal of trace carbon monoxide from hydrogen. The present disclosure further removes trace carbon monoxide from the hydrogen raw material after purification from the PSA device. Two selective adsorption devices are used. When one selective adsorption device is in an adsorption state, the other is in an adsorbent desorption and regeneration state or a standby state. In addition, when the selective adsorption device is in the adsorption state, the carbon monoxide concentration of the hydrogen at the outlet of the adsorption device is monitored. When the concentration threshold is reached, the other adsorption device is immediately replaced for adsorption, and the adsorbent in the adsorption device is desorbed and regenerated. During operation, the present disclosure does not require continuous pressure swing cyclic adsorption to effectively adsorb CO. The single adsorption cycle is long, while improving the hydrogen purity and ensuring the hydrogen yield, and realizing the production of fuel cell hydrogen. In addition, the present disclosure does not require the compressor to work continuously during operation, thereby saving energy consumption for hydrogen purification. The present disclosure effectively frees up the operating space of the front-end PSA device and does not impose strict requirements on the CO purity of the hydrogen purified by the PSA at the front end, thereby effectively improving the overall hydrogen yield, achieving ultra-deep CO removal, and producing fuel cell-grade hydrogen.

[0026] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0028] Figure 1 A schematic flow chart of a method for deep removal of trace carbon monoxide from hydrogen provided by the present disclosure;

[0029] Figure 2 A schematic diagram of a system for deep removal of trace carbon monoxide in hydrogen provided by the present disclosure.

[0030] Description of Reference Numerals

[0031] 1-first feed valve, 2-first discharge valve, 3-second feed valve, 4-second discharge valve, 5-first selective adsorption device, 6-second selective adsorption device, 7-first side line front branch desorption valve, 8-first side line rear branch desorption valve, 9-second side line front branch desorption valve, 10-second side line rear branch desorption valve, 11-hydrogen release valve, 12-hydrogen feed, 13-product hydrogen output pipeline, 14-hydrogen release pipeline, 15-gas circulation pump, 16-heating device DETAILED DESCRIPTION

[0032] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0033] In this disclosure, unless otherwise indicated, terms such as "first," "second," and "third" are used solely to distinguish between components and do not imply a specific order of connection. In this disclosure, directional terms such as "upper" and "lower" refer to the upper and lower parts of a device in normal use, while "inner" and "outer" refer to the outline of the device.

[0034] The first aspect of the present disclosure provides a method for deep removal of trace carbon monoxide in hydrogen, such as Figure 1 As shown, the following steps are included:

[0035] S1. The hydrogen feedstock 12 from the PSA unit enters the first selective adsorption unit 5, contacts the first selective adsorbent, and performs a first adsorption of carbon monoxide to obtain a first hydrogen product; and monitors the carbon monoxide concentration C1 in the hydrogen at the outlet of the first selective adsorption unit 5;

[0036] S2. When C1 reaches a concentration threshold C0, stop feeding the hydrogen feedstock into the first selective adsorption device 5 and allow the hydrogen feedstock 12 to enter the second selective adsorption device 6 to contact with the second selective adsorbent for a second adsorption of carbon monoxide to obtain a second hydrogen product; monitor the carbon monoxide concentration C2 in the hydrogen at the outlet of the second selective adsorption device 6;

[0037] and regenerating and desorbing the first selective adsorbent in the first selective adsorption device 5;

[0038] S3. When C2 reaches the concentration threshold C0, stop feeding the hydrogen raw material into the second selective adsorption device 6 and allow the hydrogen raw material 12 to enter the first selective adsorption device 5;

[0039] and regenerating and desorbing the second selective adsorbent in the second selective adsorption device 6;

[0040] S4. Repeat steps S1 to S3; wherein C0 is 0.18 to 0.20 ppm.

[0041] The present invention further removes trace carbon monoxide from the hydrogen raw material after purification from the PSA device, and adopts two selective adsorption devices. When one of the selective adsorption devices is in the adsorption state, the other is in the adsorbent desorption regeneration or standby state; and when the selective adsorption device is in the adsorption state, the carbon monoxide concentration of the hydrogen at the outlet of the adsorption device is monitored. When the concentration threshold is reached, the other adsorption device is immediately replaced for adsorption, and the adsorbent in the adsorption device is desorbed and regenerated. When the present invention is working, it does not need to perform continuous pressure swing cycle adsorption to effectively adsorb CO. The single adsorption cycle is long, and while improving the hydrogen purity and ensuring the hydrogen yield, it realizes the production of fuel cell hydrogen. In addition, the present invention does not require the compressor to work continuously during operation, thereby saving energy consumption for hydrogen purification. The present invention effectively releases the operating space of the front-end PSA device, does not make strict requirements on the purity of CO in the hydrogen purified by PSA at the front end, thereby effectively improving the overall yield of hydrogen, realizing ultra-deep removal of CO, and producing fuel cell grade hydrogen.

[0042] The range of the concentration threshold in this disclosure means that any value within the range can be used as a standard and can be selected according to actual conditions. For example, if the concentration threshold C0 is 0.18-0.20 ppm, then values ​​such as 0.18 ppm, 0.185 ppm, and 0.19 ppm can be selected according to actual conditions.

[0043] In one embodiment, Figure 2 As shown, the regeneration and desorption in step S2 includes the following steps:

[0044] Extracting gas from the first selective adsorption device 5 and returning the gas to the first selective adsorption device 5 through a first external pipeline; preferably, the method further comprises: heating the gas after extracting the gas from the first selective adsorption device 5 and returning the heated gas to the first selective adsorption device 5;

[0045] The regeneration and desorption in step S3 comprises the following steps:

[0046] Extracting the gas in the second selective adsorption device 6 and returning the gas to the second selective adsorption device 6 through a second external pipeline; preferably, the method further comprises: heating the gas after extracting the gas in the second selective adsorption device 6 and returning the heated gas to the second selective adsorption device 6.

[0047] like Figure 2As shown, the specific process flow for desorption regeneration of the first selective adsorbent in the first selective adsorption device in the present disclosure includes: extracting gas from the bottom of the first selective adsorption device outside the device by a gas extraction device (e.g. a gas extraction pump), and then the gas extracted by the pump can be heated in the external pipeline to increase the temperature of the gas; then the gas stream is introduced into the first selective adsorption device from the top of the device through the external pipeline, to realize circulation of the gas stream in the device; and the pressure in the device is reduced during the circulation of the gas stream, so that the first selective adsorbent in the device is desorbed under low pressure; and the circulation gas stream is heated to increase the temperature, which can further improve the desorption regeneration efficiency of the first selective adsorbent. In the present disclosure, after stopping the introduction of hydrogen raw material into the first selective adsorption device, part of the hydrogen in the device can be released before desorption regeneration, to reduce the pressure in the device, and then desorption regeneration is performed. The desorption regeneration process flow of the second selective adsorbent in the second selective adsorption device has the same process flow.

[0048] In a preferred embodiment, during the desorption regeneration process in step S2, the pressure in the first selective adsorption device 5 is 0.1-2.0 MPa, the temperature is 80-200℃, and the desorption regeneration time is 2-8 h.

[0049] During the desorption regeneration process in step S3, the pressure in the second selective adsorption device 6 is 0.1-2.0 MPa, the temperature is 80-200℃, and the desorption regeneration time is 2-8 h.

[0050] In an embodiment, the method further includes: detecting the carbon monoxide concentration C1 of the outlet hydrogen of the first selective adsorption device 5 by gas chromatography, and when C1 is below the concentration threshold value C0, the outlet hydrogen of the first selective adsorption device 5 is output as the first product hydrogen.

[0051] Detecting the carbon monoxide concentration C2 of the outlet hydrogen of the second selective adsorption device 6 by gas chromatography, and when C2 is below the concentration threshold value C0, the outlet hydrogen of the second selective adsorption device 6 is output as the second product hydrogen.

[0052] In the present disclosure, the carbon monoxide concentration of the hydrogen output by the selective adsorption device is detected by gas chromatography, and the product hydrogen below the concentration threshold value is output, and when the concentration reaches the concentration threshold value, the introduction of hydrogen raw material into the adsorption device can be stopped in time, which effectively ensures that the carbon monoxide concentration of the output product hydrogen meets the quality standard of fuel-grade hydrogen.

[0053] In one embodiment, the first selective adsorbent and the second selective adsorbent are respectively carbon monoxide adsorbents; the carbon monoxide adsorbent comprises a carrier and a first active component and a second active component supported on the carrier; the first active component comprises a monovalent copper compound and / or a divalent copper compound; the second active component comprises a nickel compound; the carrier comprises activated carbon, and the specific surface area of ​​the activated carbon is 400 to 2000 m 2 / g;

[0054] Optionally, the first active component is selected from one or more of cuprous oxide, cupric oxide, cuprous chloride, cupric chloride, cuprous nitrate, cupric nitrate, cuprous sulfate, cupric 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 weight%; the content of the second active component is 3-10 weight%; the weight ratio of the first active component to the second active component is (0.4-1.2): (0.075-0.15).

[0055] The carbon monoxide adsorbent obtained by introducing the first active combination and the second active component into the carrier in the present disclosure can be used as a packing layer of a fixed bed adsorption device to achieve effective adsorption of trace carbon monoxide in hydrogen, thereby improving the practical applicability of the method of deep removal of trace carbon monoxide in hydrogen disclosed in the present disclosure.

[0056] In a preferred embodiment, the shape of the carbon monoxide adsorbent includes spherical, cylindrical, and sheet-like;

[0057] The carbon monoxide adsorbent is a spherical particle with a particle size of 1 to 3 mm; the carbon monoxide adsorbent is a columnar particle with a cross-sectional diameter of 1 to 3 mm and a length of 5 to 20 mm; the carbon monoxide adsorbent is a sheet with a thickness of 0.5 to 2 mm;

[0058] Preferably, the BET specific surface area of ​​the carbon monoxide adsorbent is 300 to 1200 m 2 / g, average pore diameter of 0.3-2nm, pore volume of 0.25-0.6cm 3 / g.

[0059] In one embodiment, the carbon monoxide adsorbent can be prepared by the following steps:

[0060] a. mixing a first active component precursor and a second active component precursor with water to obtain a precursor solution;

[0061] b. immersing the support in the precursor solution to obtain a mixed material;

[0062] c. Drying and roasting the mixture.

[0063] The carbon monoxide adsorbent prepared by the method provided by the present invention can load the first active component and the second active component in the carrier pores and on the carrier surface, and the structural size and performance of the prepared catalyst are more suitable for practical industrial applications, especially for the method for removing trace carbon monoxide from the hydrogen raw material from the PSA device provided by the present invention. The filler layers of the first selective adsorption device and the second selective adsorption device are beneficial to improving the carbon monoxide removal efficiency of the selective adsorption device, extending the single adsorption cycle of obtaining product hydrogen with a carbon monoxide concentration below the concentration threshold C0 (such as 0.2 ppm), and are easier to desorb and regenerate in industrial applications.

[0064] In one embodiment,

[0065] In step a, the first active component precursor is a water-soluble copper salt, preferably one or more selected from copper chloride, copper nitrate, copper acetate, copper formate, and copper sulfate; the second active component precursor is a water-soluble nickel salt, preferably one or more selected from nickel sulfate, nickel nitrate, nickel acetate, and nickel citrate; the BET specific surface area of ​​the carrier is 300 to 2000 m 2 / g, pore volume 0.5~0.8cm 3 / g;

[0066] In step b, the immersion temperature is 25-70° C. and the immersion time is 0.5-4 h;

[0067] In step c, the drying temperature is 60-110° C., and the drying time is 2-8 hours; the calcination temperature is 240-300° C., and the calcination time is 3-6 hours, and the calcination atmosphere is argon or nitrogen.

[0068] In one embodiment, during the first carbon monoxide adsorption process, the adsorption operating pressures of the first selective adsorption device 5 and the second selective adsorption device 6 are respectively the same as the pressure of the hydrogen feed 12, where the pressure of the hydrogen feed 12 is 1.5 to 6.0 MPa. In the present disclosure, the adsorption pressures of the first and second selective adsorption devices do not need to be adjusted; they can simply be kept the same as the hydrogen feed pressure.

[0069] In one embodiment, during the first carbon monoxide adsorption and the second carbon monoxide adsorption, the adsorption temperature in the first selective adsorption device 5 and the second selective adsorption device 6 is independently 10 to 60°C, preferably 10 to 45°C, and the volume space velocity in the first selective adsorption device 5 and the second selective adsorption device 6 is independently 1000 to 9000 h -1 , preferably 2000~4000h h -1 .

[0070] In a preferred embodiment, the packing density of the adsorbent naturally accumulated in the first and second selective adsorption devices 5 and 6 is independently 0.4-0.8 g / mL, preferably 0.5-0.7 g / mL.

[0071] Optionally, the concentration of carbon monoxide in the hydrogen feed 12 is 1-500 ppm.

[0072] The adsorption conditions in the present disclosure, such as pressure, temperature, and volume space velocity, are more matched with the performance of the carbon monoxide adsorbent used in the present disclosure and the specific packing mode in the adsorption device, and are more suitable for the hydrogen feed from the PSA device, and are more conducive to the removal of carbon monoxide in the process application.

[0073] In an embodiment, the concentration of carbon monoxide in the hydrogen feed 12 is 1-500 ppm. The present disclosure not only has a removal effect below the concentration threshold (such as 0.2 ppm) for hydrogen feed with a lower carbon monoxide concentration (such as 1 ppm), but also easily achieves a concentration threshold (such as 0.2 ppm) below and has a longer single adsorption cycle for hydrogen feed with a high carbon monoxide concentration (such as 500 ppm).

[0074] The second aspect of the present disclosure provides a system for deep removal of trace carbon monoxide in hydrogen, such as Figure 2 as shown, comprising:

[0075] Two parallelly arranged selective adsorption devices, each of which comprises a selective adsorbent bed and a carbon monoxide detector for detecting the carbon monoxide concentration of the outlet hydrogen.

[0076] A switching control device for controlling the hydrogen feed to alternately enter the two selective adsorption devices according to the carbon monoxide concentration of the outlet hydrogen.

[0077] The switching control device used in the present disclosure can adopt conventional control devices known in the art, for example, it can include a controller, pipelines and valves, etc. For example, a valve can be set as a feed valve on the hydrogen raw material introduction pipeline of a selective adsorption device, and the valve is connected to the controller signal. The controller controls the opening and closing of the valve by whether the carbon monoxide concentration detected by the carbon monoxide detector reaches the concentration. For example, if the carbon monoxide detector detects that the carbon monoxide concentration does not reach the concentration threshold, the controller can control the valve to remain open and continue to work by the original adsorber; if the carbon monoxide concentration reaches the concentration threshold, the controller controls the valve to close to stop the introduction of raw hydrogen into the working selective adsorption device; and controls another feed valve on the raw hydrogen introduction pipeline of another selective adsorption device to open so that the raw hydrogen enters the other selective adsorption device. Specifically, it can be set according to actual usage.

[0078] In one embodiment, Figure 2 As shown, the system includes a first selective adsorption device 5, a second selective adsorption device 6, a raw material delivery pipeline, a first raw material feed branch, a first hydrogen discharge branch, a second raw material feed branch, a second hydrogen discharge branch, a fuel cell-grade hydrogen output pipeline, and a side-line desorption regeneration unit; the inlet end of the raw material delivery pipeline is used to communicate with the hydrogen raw material 12 treated by the PSA device, and the outlet end of the raw material delivery pipeline is respectively communicated with the inlet end of the first raw material feed branch and the inlet end of the second raw material feed branch;

[0079] The outlet end of the first branch pipe for hydrogen discharge and the outlet end of the second branch pipe for hydrogen discharge are respectively connected to the inlet end of the fuel cell-grade hydrogen output pipeline;

[0080] The first selective adsorption device 5 is provided with a first hydrogen feed inlet and a first hydrogen discharge port; a first selective adsorbent bed is provided between the first hydrogen feed inlet and the first hydrogen discharge port; the first hydrogen feed inlet is connected to the outlet end of the first feed branch pipe for introducing the hydrogen feed 12 treated by the PSA device into the first selective adsorption device 5; the first hydrogen discharge port is connected to the inlet end of the first hydrogen discharge branch pipe;

[0081] The second selective adsorption device 6 is provided with a second hydrogen feed inlet and a second hydrogen discharge port; a second selective adsorbent bed is provided between the second hydrogen feed inlet and the second hydrogen discharge port; the second hydrogen feed inlet is connected to the outlet end of the second feed branch pipe for introducing the hydrogen feed 12 treated by the PSA device into the second selective adsorption device 6; the second hydrogen discharge port is connected to the inlet end of the second hydrogen discharge branch pipe;

[0082] The first hydrogen feed inlet and the first hydrogen outlet of the first selective adsorption device 5 are respectively connected to the side desorption regeneration unit; the second hydrogen feed inlet and the second hydrogen outlet of the second selective adsorption device 6 are respectively connected to the side desorption regeneration unit.

[0083] In a specific embodiment, Figure 2 As shown, the side desorption regeneration unit includes a 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 hydrogen outlet of the first selective adsorption device 5 is connected to the first hydrogen feed inlet of the first selective adsorption device 5 in sequence through the first side line front branch pipe, the circulation main pipe and the first side line rear branch pipe, the first side line front branch pipe is provided with a first side line front branch pipe desorption valve 7, the first side line rear branch pipe is provided with a first side line rear branch pipe desorption valve 8, the second hydrogen outlet of the second selective adsorption device 6 is connected to the second hydrogen feed inlet of the second selective adsorption device 6 in sequence through the second side line front branch pipe, the circulation main pipe and the second side line rear branch pipe, the second side line front branch pipe is provided with a second side line front branch pipe desorption valve 9, and the second side line rear branch pipe is provided with a second side line rear branch pipe desorption valve 10;

[0084] A gas circulation pump 15 and an optional heating device 16 are connected to the circulation main pipe; the heating inlet of the heating device 16 is connected to the suction outlet of the gas circulation pump 15, and the heating outlet of the heating device 16 is connected to the first side line rear branch pipe desorption valve 8 and is connected to the second hydrogen feed inlet of the second selective adsorption device 6 through the second side line rear branch pipe desorption valve 10;

[0085] Optionally, the system further includes a hydrogen release pipeline 14 and a hydrogen release valve 11. The hydrogen release valve 11 is provided on the hydrogen release pipeline 14. The inlet end of the hydrogen release pipeline 14 is respectively connected to the outlet end of the first discharge valve 2 and the outlet end of the second discharge valve 4.

[0086] In a preferred embodiment, the system has a first working state and a second working state;

[0087] In the first working state:

[0088] Open the first feed valve 1 and the first discharge valve 2, and close the second feed valve 3, the second discharge valve 4, the first side line front branch pipe desorption valve 7, the first side line rear branch pipe desorption valve 8, the second side line front branch pipe desorption valve 9, the second side line rear branch pipe desorption valve 10 and the hydrogen release valve 11, so that the hydrogen feed 12 enters the first selective adsorption device 5 through the first feed valve 1 for the first adsorption of carbon monoxide; and the obtained first product hydrogen is output through the first discharge valve 2 and the product hydrogen output pipeline 13;

[0089] In the second working state:

[0090] Close the first feed valve 1, open the second feed valve 3 and the second discharge valve 4, so that the hydrogen raw material 12 enters the second selective adsorption device 6 through the second feed valve 3 for the second adsorption of carbon monoxide; and the obtained second product hydrogen is output through the second discharge valve 4 and the product hydrogen output pipeline 13.

[0091] In a further preferred embodiment, the first working state further includes:

[0092] The second side line front branch pipe desorption valve 9 and the second side line rear branch pipe desorption valve 10 are opened, and the gas circulation pump 15 is connected to the gas in the second selective adsorption device 6, so that the gas in the second selective adsorption device 6 circulates in sequence through the second discharge valve 4, the second side line front branch pipe desorption valve 9, the gas circulation pump 15 and the second side line rear branch pipe desorption valve 10;

[0093] The second working state also includes:

[0094] The first side line front branch pipe desorption valve 7 and the first side line rear branch pipe desorption valve 8 are opened, and the gas circulation pump 15 is connected to the internal gas of the first selective adsorption device 5, so that the gas in the first selective adsorption device 5 circulates in sequence through the first discharge valve 2, the first side line front branch pipe desorption valve 7, the gas circulation pump 15 and the first side line rear branch pipe desorption valve 8.

[0095] In the present disclosure, when the system is in the first working state, that is, the first selective adsorption device is working, it also includes desorption and regeneration of the adsorbent in the second selective adsorption device; and when the system is in the second working state, that is, the second selective adsorption device is working, it also includes desorption and regeneration of the adsorbent in the first selective adsorption device.

[0096] In a specific embodiment, using Figure 2 The specific process flow of the system shown in the figure for deep removal of carbon monoxide from the hydrogen feedstock of the PSA unit includes:

[0097] The first feed valve 1 and the first discharge valve 2 are opened, and the second feed valve 3, the second discharge valve 4, the first side line front branch desorption valve 7, the first side line rear branch desorption valve 8, the second side line front branch desorption valve 9, the second side line rear branch desorption valve 10 and the hydrogen release valve 11 are closed. The hydrogen feed 12 from the PSA device enters the top of the first selective adsorption device through the feed delivery pipeline and the first feed branch, flows from top to bottom in the adsorption device and passes through the first selective adsorbent to adsorb carbon monoxide in the hydrogen feed, and the obtained first product hydrogen flows out through the bottom of the tower. At the same time, the carbon monoxide concentration C1 in the outlet hydrogen of the first selective adsorption device 5 is monitored by gas chromatography. When C1 does not reach the concentration threshold C0, the first selective adsorption device continues to remove carbon monoxide, and the obtained first product hydrogen is input into hydrogen through the first hydrogen discharge branch and the fuel cell-grade hydrogen output pipeline;

[0098] When C1 reaches the concentration threshold C0, the first feed valve 1 is closed immediately, and the second feed valve 3 and the second discharge valve 4 are opened, the hydrogen raw material 12 is stopped from being introduced into the first selective adsorption device 5, and the hydrogen raw material 12 is introduced into the top of the second selective adsorption device via the raw material delivery pipeline and the raw material feed second branch, flows from top to bottom in the adsorption device, and passes through the second selective adsorbent to adsorb carbon monoxide in the hydrogen raw material, the obtained second product hydrogen is discharged from the bottom of the tower, and the carbon monoxide concentration C2 in the outlet hydrogen of the second selective adsorption device is monitored by gas chromatography; when C2 does not reach the concentration threshold C0, the carbon monoxide removal by the second selective adsorption device is continued, and the obtained second product hydrogen is input into the hydrogen fuel cell via the hydrogen discharge second branch and the fuel cell grade hydrogen output pipeline;

[0099] And after stopping the introduction of the hydrogen raw material into the first selective adsorption device, the first selective adsorbent in the adsorption device is subjected to desorption regeneration, which includes: first opening the hydrogen release valve 11, releasing part of the gas in the adsorption device from the bottom of the first selective adsorption device via the hydrogen release pipeline 14, then closing the hydrogen release valve 11, opening the first side line front branch desorption valve 7 and the first side line rear branch desorption valve 8, and connecting the gas circulating pump 15 with the gas in the first selective adsorption device 5, the gas circulating pump 15 extracts the gas in the first selective adsorption device 5 and pressurizes the extracted gas via the gas circulating pump 15, and after pressurization, the gas enters the heating device 16 for heating and warming, and after warming, the gas returns to the inside of the first selective adsorption device 5 via the first side line rear branch desorption valve 8, so that the first selective adsorbent in the adsorption device is subjected to desorption regeneration under the conditions of low pressure and warming;

[0100] When C2 reaches the concentration threshold C0, the second feed valve 3 is closed immediately, and the first feed valve 1 and the first discharge valve 2 are opened, the introduction of the hydrogen raw material 12 into the second selective adsorption device 6 is stopped, and the hydrogen raw material is introduced into the first selective adsorption device 1 for carbon monoxide adsorption and removal;

[0101] And after stopping introducing hydrogen raw material into the second selective adsorption device, the method further comprises desorbing and regenerating the second selective adsorbent in the adsorption device, including: first opening the hydrogen release valve 11, releasing part of the gas in the adsorption device from the bottom of the second selective adsorption device through the hydrogen release pipeline 14, then closing the hydrogen release valve 11, opening the second side line front branch desorption valve 9 and the second side line rear branch desorption valve 10, and connecting the gas circulating pump 15 with the gas in the second selective adsorption device 6, so that the gas circulating pump 15 extracts the gas in the second selective adsorption device 6 and pressurizes the extracted gas through the gas circulating pump 15, and after pressurization, the gas enters the heating device 16 for heating and warming, and after warming, the gas returns to the second selective adsorption device 6 through the second side line rear branch desorption valve 10, so that the second selective adsorbent in the adsorption device is desorbed and regenerated under the conditions of low pressure and warming.

[0102] Then, according to the above steps, the hydrogen raw material 12 is repeatedly introduced into the first selective adsorption device or the second selective adsorption device for removing carbon monoxide, and the selective adsorbent in the adsorption device without introducing hydrogen raw material is desorbed and regenerated.

[0103] The present disclosure is further described below in conjunction with examples and comparative examples.

[0104] It should be noted that the raw materials / reagents used in the following examples are separately described, and if not separately described, they are commercially available chemical reagents, and there is no special limitation on this.

[0105] Preparation Example 1

[0106] The present preparation example is used for preparing a carbon monoxide adsorbent, specifically comprising:

[0107] Dissolve 2 g of anhydrous copper chloride and 3 g of anhydrous copper acetate and 1 g of nickel citrate in water, fully stir and dissolve, then disperse and impregnate the solution on 5 g of a high specific surface area activated carbon carrier, control the temperature of the rotary evaporator flask at 60°C, and rotate and evaporate in a water bath at a speed of 20 rpm, the specific surface area of the activated carbon is 1200 m 2 / g, control the copper loading (first active component) to be 6 mmol / g of the activated carbon; control the nickel loading (second active component) to be 1 mmol / g of the activated carbon. After impregnation, the carrier is dried as a whole at 80°C, and then sintered under inert gas protection at 260°C to prepare a carbon monoxide adsorbent, which is denoted as sample A. The weight ratio of the first active component to the second active component is 1:0.125.

[0108] XPS characterization of the sintered product showed that the active components included Cu and Ni; the adsorbent had a carbon monoxide adsorption capacity of 200 mL / g; the adsorbent was columnar with a diameter of 1 mm and a length of 8 mm; and a BET specific surface area of ​​800 m 2 / g, average pore diameter of 1nm, pore volume of 0.4cm 3 / g.

[0109] Comparative Example 1

[0110] Dissolve 225g of anhydrous copper nitrate in water and stir thoroughly to dissolve. The solution is then dispersed and impregnated onto 100g of a high-surface-area activated carbon support. The rotary evaporator flask is maintained at 60°C and evaporation is performed at 20 rpm in a water bath to control the copper loading to 12.0 mmol / g of activated carbon. The impregnated support is then dried at 80°C and then sintered at 180°C under inert gas to produce a carbon monoxide adsorbent, designated Sample D-1.

[0111] In the following examples and comparative examples, the carbon monoxide concentration threshold is 0.2 ppm.

[0112] Example 1

[0113] 2 ml of special adsorbent A was placed in a single fixed bed adsorber, activated at 300 ° C for 120 minutes under the protection of nitrogen, cooled to room temperature, and then high-purity hydrogen containing 10 ppm of carbon monoxide was introduced. The gas flow rate was controlled at 6 L / h and the space velocity was controlled at 3000 h -1 The breakthrough curve of the adsorbent was measured at an operating pressure of 2.1 MPa and a test temperature of 35°C. The packing density of the naturally accumulated adsorbent in the fixed-bed adsorber was 0.55 g / mL.

[0114] The initial concentration of carbon monoxide in the product gas was 0 ppm. After 36 hours, the carbon monoxide concentration was higher than 0.2 ppm and the test ended.

[0115] Example 2

[0116] 2 ml of special adsorbent A was placed in a single fixed bed adsorber, activated at 300 ° C for 120 minutes under the protection of nitrogen, cooled to room temperature, and then high-purity hydrogen containing 1.0 ppm carbon monoxide was introduced. The gas flow rate was controlled at 6 L / h and the space velocity was controlled at 3000 h -1 The breakthrough curve of the adsorbent was measured at an operating pressure of 6.0 MPa and a test temperature of 25°C. The packing density of the naturally accumulated adsorbent in the fixed-bed adsorber was 0.55 g / mL.

[0117] The initial concentration of carbon monoxide in the product gas was 0 ppm. After 300 hours, the carbon monoxide concentration was higher than 0.2 ppm and the test ended.

[0118] Example 3

[0119] 2 ml of special adsorbent A was placed in a single fixed bed adsorber, activated at 300 ° C for 120 minutes under the protection of nitrogen, cooled to room temperature, and then high-purity hydrogen containing 500 ppm of carbon monoxide was introduced. The gas flow rate was controlled at 2 L / h and the space velocity was controlled at 1000 h -1 The breakthrough curve of the adsorbent was measured at an operating pressure of 4.0 MPa and a test temperature of 25°C. The packing density of the naturally accumulated adsorbent in the fixed-bed adsorber was 0.55 g / mL.

[0120] The initial concentration of carbon monoxide in the product gas was 0 ppm. After 24 hours, the carbon monoxide concentration was higher than 0.2 ppm and the test ended.

[0121] Comparative Example 2

[0122] The sample D-1 in Comparative Example 1 was tested using the same method as in Example 3, with high-purity hydrogen containing 500 ppm of carbon monoxide introduced. The test conditions were the same as in Example 3.

[0123] After 0.5 hours, the carbon monoxide concentration in the product gas was higher than 0.2 ppm and the test ended.

[0124] Comparative Example 3

[0125] Conventional molecular sieve is used as the adsorbent, and the molecular sieve is commercial 5A molecular sieve.

[0126] 2 ml of commercial 5A molecular sieve adsorbent was placed in a single fixed-bed adsorber and activated at 300 °C for 120 minutes under nitrogen protection. The temperature was then cooled to room temperature. High-purity hydrogen containing 1 ppm carbon monoxide was then introduced. The gas flow rate was controlled at 6 L / h and the space velocity was controlled at 3000 h -1 , operating pressure 2.1Mpa, test temperature 25℃, test the breakthrough curve of the adsorbent.

[0127] The initial concentration of carbon monoxide in the product gas was 0.4ppm, which could never meet the standard requirement of <0.2ppm.

[0128] Comparative Example 4

[0129] Conventional molecular sieve is used as the adsorbent, and the molecular sieve is commercial 13X molecular sieve.

[0130] 2 ml of commercial 13X molecular sieve adsorbent was placed in a single fixed-bed adsorber and activated at 300 °C for 120 minutes under nitrogen protection. The temperature was then cooled to room temperature. High-purity hydrogen containing 1 ppm carbon monoxide was then introduced. The gas flow rate was controlled at 6 L / h and the space velocity was controlled at 3000 h -1, operating pressure 30 MPa, test temperature 25℃, and breakthrough curve of the tested adsorbent.

[0131] The initial concentration of carbon monoxide in the product gas was 0.1 ppm, and after 3 hours, the concentration was higher than 0.2 ppm.

[0132] Compared with Examples 1-3 and Comparative Examples 2-4 above, it is shown that the adsorbent A prepared by the present disclosure has better adsorption performance and longer adsorption cycle in a single fixed bed adsorber test.

[0133] Example 4

[0134] The process system shown in Figure 1 was used for deep removal of trace carbon monoxide in hydrogen, specifically including:

[0135] Each 2 mL of special adsorbent A (i.e. the volume of the adsorbent bed was 2 mL) was placed in two fixed bed adsorbers Ta (first selective adsorption device) and Tb (second selective adsorption device) (the packing density of the naturally packed adsorbent in the two fixed bed adsorbers was 0.55 g / mL), activated at 300℃ for 120 minutes under the protection of nitrogen, cooled to room temperature, and then high-purity hydrogen containing 1.0 ppm of carbon monoxide was introduced into Ta, the gas flow rate was controlled at 6 L / h, and the space velocity was controlled at 3000 h -1 -1, operating pressure 4.0 MPa, test temperature 25℃, breakthrough curve of the tested adsorbent, after Ta was deactivated (i.e. the concentration of carbon monoxide in the hydrogen gas at the outlet of Ta reached the concentration threshold, C0 was 0.2 ppm), Tb was connected to continue the adsorption experiment. After the hydrogen gas was discharged from Ta to a pressure of 0.3 MPa, the gas in the adsorption device was pumped to circulate, and the circulating gas was heated to 120℃, the adsorbent in the adsorption device was desorbed and regenerated for 6 hours, then cooled to 25℃, and the remaining hydrogen gas was discharged.

[0136] The initial concentration of carbon monoxide in the product gas of Ta was 0 ppm, and after 260 hours, the concentration of carbon monoxide was higher than 0.2 ppm, and Ta reactor completed regeneration when the adsorption in Tb reactor. When the concentration of carbon monoxide in the adsorption in Tb reactor was higher than 0.2 ppm, Ta reactor was turned in for adsorption again, and the second adsorption time of Ta still remained about 260 hours.

[0137] Comparative Example 5

[0138] The same method as in Example 4 was used, except that the carbon monoxide adsorbent A was replaced by D-1 prepared in Comparative Example 1.

[0139] The initial CO concentration in the Ta product gas was 1 ppm. After 12 hours, the CO concentration rose above 0.2 ppm, and the Ta reactor completed regeneration during adsorption in the Tb reactor. Once the CO concentration in the Tb reactor rose above 0.2 ppm, the gas was transferred to the Ta reactor for another adsorption cycle, which lasted approximately 12 hours.

[0140] Comparison between Example 4 and Comparative Example 5 shows that the use of the adsorbent and treatment system provided by the present disclosure for deep removal of trace carbon monoxide in hydrogen has better adsorption performance and a longer adsorption cycle.

[0141] Example 5

[0142] 2 mL of special adsorbent A was placed in two fixed-bed adsorbers Ta and Tb, activated at 300 °C for 120 minutes under nitrogen protection, cooled to room temperature, and then high-purity hydrogen containing 5.0 ppm carbon monoxide was introduced into Ta. The gas flow rate was controlled at 6 L / h and the space velocity was controlled at 1000 h -1 The adsorbent breakthrough curve was measured at an operating pressure of 2.1 MPa and a test temperature of 60°C. After Ta deactivation (i.e., the carbon monoxide concentration in the hydrogen at the Ta outlet reached the threshold, C0, of 0.2 ppm), Tb was connected to continue the adsorption experiment. After the Ta reactor discharged hydrogen to a pressure of 0.3 MPa, a pump was used to circulate the gas within the adsorption device. The circulating gas was heated to 160°C, and the adsorbent in the adsorption device was desorbed and regenerated for 4 hours. The temperature was then lowered to 25°C, and the remaining hydrogen was discharged.

[0143] The initial CO concentration in the Ta product gas was 0 ppm. After 200 hours, the CO concentration rose above 0.2 ppm, indicating that the Ta reactor had completed regeneration during adsorption in the Tb reactor. Once the CO concentration in the Tb reactor rose above 0.2 ppm, the gas was transferred to the Ta reactor for another adsorption cycle, which lasted approximately 200 hours.

[0144] Example 6

[0145] 2 mL of each special adsorbent was placed in two fixed-bed adsorbers Ta and Tb, activated at 300 ° C for 120 minutes under the protection of nitrogen, cooled to room temperature, and then high-purity hydrogen containing 5.0 ppm of carbon monoxide was introduced into the Ta, with the gas flow rate controlled at 6 L / h and the space velocity controlled at 2000 h -1, the operating pressure is 2.5 MPa, the test temperature is 15℃, the breakthrough curve of the tested adsorbent is obtained, after Ta is deactivated (i.e. the carbon monoxide concentration in the hydrogen gas at the outlet of Ta reaches the concentration threshold, C0 is 0.2 ppm), Tb is connected to continue the adsorption experiment. After the hydrogen gas at the outlet of Ta is discharged to a pressure of 0.3 MPa, the gas in the adsorption device is pumped to circulate, and the circulating gas is heated to 160℃, the adsorbent in the adsorption device is desorbed and regenerated for 4 hours, then cooled to 25℃, and the remaining hydrogen gas is discharged.

[0146] The initial carbon monoxide concentration in the product gas of Ta is 0 ppm, and after 300 hours, the carbon monoxide concentration is higher than 0.2 ppm, and the regeneration of Ta reactor is completed when the adsorption of Tb reactor is completed. When the carbon monoxide concentration in the adsorption of Tb reactor is higher than 0.2 ppm, the adsorption of Ta reactor is started again, and the second adsorption time of Ta reactor is still maintained for about 300 hours.

[0147] In the above two fixed bed adsorbers, the packing density of the naturally packed adsorbent is the same as that in Example 5.

[0148] Comparing Example 5 and Example 6, it can be seen that when the volume space velocity is 2000-4000 h -1 Under the above conditions, the adsorbent and treatment system provided by the present disclosure have better adsorption performance and longer adsorption cycle for deep removal of trace carbon monoxide in hydrogen gas.

[0149] The preferred embodiments of the present disclosure are described in detail above in combination with the drawings, but the present disclosure is not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the present disclosure within the technical concept of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0150] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0151] In addition, various different embodiments of the present disclosure can also be combined in any manner, as long as they do not deviate from the idea of the present disclosure, and they should also be considered as disclosed by the present disclosure.

Claims

1. A method for deep removal of trace carbon monoxide in hydrogen, characterized in that: The following steps are involved: S1, allowing the hydrogen feedstock (12) from the PSA device to enter the first selective adsorption device (5), contact with the first selective adsorbent to perform a first adsorption of carbon monoxide, and obtain a first product hydrogen; monitoring the carbon monoxide concentration C1 in the outlet hydrogen of the first selective adsorption device (5); S2, when C1 reaches the concentration threshold C0, stop feeding the hydrogen raw material into the first selective adsorption device (5), and allow the hydrogen raw material (12) to enter the second selective adsorption device (6), contact with the second selective adsorbent to perform a second adsorption of carbon monoxide, and obtain a second product hydrogen; monitor the carbon monoxide concentration C2 in the outlet hydrogen of the second selective adsorption device (6); and regenerating and desorbing the first selective adsorbent in the first selective adsorption device (5); S3, when C2 reaches the concentration threshold C0, stop feeding the hydrogen raw material into the second selective adsorption device (6), and allow the hydrogen raw material (12) to enter the first selective adsorption device (5); and regenerating and desorbing the second selective adsorbent in the second selective adsorption device (6); S4, repeat steps S1 to S3; wherein C0 is 0.18 to 0.20 ppm; The first selective adsorbent and the second selective adsorbent are respectively carbon monoxide adsorbents; the carbon monoxide adsorbent includes a carrier and a first active component and a second active component supported 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; the carrier includes activated carbon; 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 regeneration and desorption process in step S2 comprises the following steps: extracting gas from the first selective adsorption device (5) and returning the gas to the first selective adsorption device (5) via a first external pipeline; The regeneration and desorption in step S3 comprises the following steps: The gas in the second selective adsorption device (6) is extracted and returned to the second selective adsorption device (6) through a second external pipeline.

3. The method according to claim 2, characterized in that The regeneration and desorption in step S2 further comprises the following steps: extracting the gas in the first selective adsorption device (5) and heating it, so that the heated gas returns to the first selective adsorption device (5); The regeneration desorption described in step S3 further includes the following steps: extracting the gas in the second selective adsorption device (6) and heating it, so that the heated gas returns to the second selective adsorption device (6).

4. The method according to claim 1, wherein The method further includes: Using gas chromatography to detect the carbon monoxide concentration C1 of the hydrogen at the outlet of the first selective adsorption device (5), when C1 is below the concentration threshold C0, the hydrogen at the outlet of the first selective adsorption device (5) is output as the first product hydrogen; and The carbon monoxide concentration C2 of the outlet hydrogen of the second selective adsorption device (6) is detected by gas chromatography. When C2 is below the concentration threshold C0, the outlet hydrogen of the second selective adsorption device (6) is output as the second product hydrogen.

5. The method according to claim 1, wherein The specific surface area of ​​the activated carbon is 400~2000m 2 / g.

6. The method according to claim 1, characterized in that The first active component is selected from one or more of cuprous oxide, cupric oxide, cuprous chloride, cupric chloride, cuprous nitrate, cupric nitrate, cuprous sulfate, cupric 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.

7. The method according to claim 1, characterized in that The shape of the carbon monoxide adsorbent includes spherical, cylindrical, and sheet-like; The carbon monoxide adsorbent is in the form of spherical particles with a particle size of 1 to 3 mm; the carbon monoxide adsorbent is in the form of a column with a cross-sectional diameter of 1 to 3 mm and a length of 5 to 20 mm; the carbon monoxide adsorbent is in the form of a sheet with a thickness of 0.5 to 2 mm.

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

9. The method according to claim 1, characterized in that The carbon monoxide adsorbent is prepared by the following steps: a. mixing a first active component precursor and a second active component precursor with water to obtain a precursor solution; b. immersing the support in the precursor solution to obtain a mixed material; c. Drying and roasting the mixture.

10. The method according to claim 9, 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; the BET specific surface area of ​​the carrier is 300~2000m 2 / g, pore volume 0.5~0.8cm 3 / g; In step b, the immersion temperature is 25-70° C. and the immersion time is 0.5-4 h; In step c, the drying temperature is 60-110° C., and the drying time is 2-8 hours; the calcination temperature is 240-300° C., and the calcination time is 3-6 hours, and the calcination atmosphere is argon or nitrogen.

11. The method according to claim 10, 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.

12. The method according to claim 1, characterized in that During the first carbon monoxide adsorption process, the adsorption operating pressures of the first selective adsorption device (5) and the second selective adsorption device (6) are respectively the same as the pressure of the hydrogen raw material (12), and the pressure of the hydrogen raw material (12) is 1.5-6.0 MPa.

13. The method according to claim 1, wherein During the first carbon monoxide adsorption and the second carbon monoxide adsorption, the adsorption temperature in the first selective adsorption device (5) and the second selective adsorption device (6) is independently 10-60°C, and the volume space velocity in the first selective adsorption device (5) and the second selective adsorption device (6) is independently 1000-9000h -1 .

14. The method according to claim 13, wherein: The adsorption temperature in the first selective adsorption device (5) and the second selective adsorption device (6) is independently 10-45°C, and the volume space velocity in the first selective adsorption device (5) and the second selective adsorption device (6) is independently 2000-4000h -1 .

15. The method according to claim 1, wherein The packing density of the naturally accumulated adsorbent in the first selective adsorption device (5) and the second selective adsorption device (6) is independently 0.4-0.8 g / mL.

16. The method according to claim 15, characterized in that The packing density of the naturally accumulated adsorbent in the first selective adsorption device (5) and the second selective adsorption device (6) is independently 0.5-0.7 g / mL.

17. The method according to claim 1, wherein The concentration of carbon monoxide in the hydrogen raw material (12) is 1 to 500 ppm.

18. The method according to claim 2, characterized in that During the desorption and regeneration process in step S2, the gas pressure in the first selective adsorption device (5) is 0.1-2.0 MPa, the temperature is 80-200°C, and the desorption and regeneration time is 2-8 hours; During the desorption and regeneration process in step S3, the gas pressure in the second selective adsorption device (6) is 0.1-2.0 MPa, the temperature is 80-200°C, and the desorption and regeneration time is 2-8 hours.

19. A system for the method for deep removal of trace carbon monoxide from hydrogen according to claim 1, characterized in that: include: Two selective adsorption devices arranged in parallel, each of the selective adsorption devices comprising a selective adsorbent bed and a carbon monoxide detector, the carbon monoxide detector being used to detect the carbon monoxide concentration of hydrogen at the device outlet; The switching control device is used to control the hydrogen raw material to alternately enter the two selective adsorption devices according to the carbon monoxide concentration of the outlet hydrogen.

20. The system according to claim 19, wherein: The system comprises a first selective adsorption device (5), a second selective adsorption device (6), a raw material delivery pipeline, a first raw material feed branch, a first hydrogen discharge branch, a second raw material feed branch, a second hydrogen discharge branch, a fuel cell-grade hydrogen output pipeline, and a side-line desorption regeneration unit; the inlet end of the raw material delivery pipeline is used to communicate with the hydrogen raw material (12) treated by the PSA device, and the outlet end of the raw material delivery pipeline is respectively communicated with the inlet end of the first raw material feed branch and the inlet end of the second raw material feed branch; The outlet end of the first branch pipe for hydrogen discharge and the outlet end of the second branch pipe for hydrogen discharge are respectively connected to the inlet end of the fuel cell-grade hydrogen output pipeline; The first selective adsorption device (5) is provided with a first hydrogen raw material inlet and a first hydrogen discharge port; a first selective adsorbent bed is provided between the first hydrogen raw material inlet and the first hydrogen discharge port; the first hydrogen raw material inlet is connected to the outlet end of the first raw material feed branch pipe for introducing the hydrogen raw material (12) treated by the PSA device into the first selective adsorption device (5); the first hydrogen discharge port is connected to the inlet end of the first hydrogen discharge branch pipe; The second selective adsorption device (6) is provided with a second hydrogen raw material inlet and a second hydrogen discharge port; a second selective adsorbent bed is provided between the second hydrogen raw material inlet and the second hydrogen discharge port; the second hydrogen raw material inlet is connected to the outlet end of the second raw material feed branch pipe for introducing the hydrogen raw material (12) treated by the PSA device into the second selective adsorption device (6); the second hydrogen discharge port is connected to the inlet end of the second hydrogen discharge branch pipe; The first hydrogen feed inlet and the first hydrogen outlet of the first selective adsorption device (5) are respectively connected to the side desorption regeneration unit; the second hydrogen feed inlet and the second hydrogen outlet of the second selective adsorption device (6) are respectively connected to the side desorption regeneration unit.

21. The system according to claim 20, wherein: The side line desorption regeneration unit comprises a 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 hydrogen outlet of the first selective adsorption device (5) is connected to the first hydrogen raw material inlet of the first selective adsorption device (5) in sequence through the first side line front branch pipe, the circulation main pipe and the first side line rear branch pipe, the first side line front branch pipe is provided with a first side line front branch pipe desorption valve (7), the first side line rear branch pipe is provided with a first side line rear branch pipe desorption valve (8), the second hydrogen outlet of the second selective adsorption device (6) is connected to the second hydrogen raw material inlet of the second selective adsorption device (6) in sequence through the second side line front branch pipe, the circulation main pipe and the second side line rear branch pipe, the second side line front branch pipe is provided with a second side line front branch pipe desorption valve (9), and the second side line rear branch pipe is provided with a second side line rear branch pipe desorption valve (10); A gas circulation pump (15) and a heating device (16) are connected to the circulation main pipe; the heating inlet of the heating device (16) is communicated with the suction outlet of the gas circulation pump (15); the heating outlet of the heating device (16) is communicated with the first hydrogen raw material inlet of the first selective adsorption device (5) via the first side line rear branch pipe desorption valve (8), and is communicated with the second hydrogen raw material inlet of the second selective adsorption device (6) via the second side line rear branch pipe desorption valve (10).

22. The system according to claim 21, wherein: The system further comprises a hydrogen release pipeline (14) and a hydrogen release valve (11), wherein the hydrogen release valve (11) is arranged on the hydrogen release pipeline (14), and the inlet end of the hydrogen release pipeline (14) is respectively connected to the outlet end of the first discharge valve (2) and the outlet end of the second discharge valve (4).

23. The system according to claim 22, wherein: The system has a first working state and a second working state; In the first working state: The first feed valve (1) and the first discharge valve (2) are opened, and the second feed valve (3), the second discharge valve (4), the first side line front branch pipe desorption valve (7), the first side line rear branch pipe desorption valve (8), the second side line front branch pipe desorption valve (9), the second side line rear branch pipe desorption valve (10) and the hydrogen release valve (11) are closed, so that the hydrogen raw material (12) enters the first selective adsorption device (5) through the first feed valve (1) to perform the first adsorption of carbon monoxide; and the first product hydrogen obtained is output through the first discharge valve (2) and the product hydrogen output pipeline (13); In the second working state: The first feed valve (1) is closed, and the second feed valve (3) and the second discharge valve (4) are opened, so that the hydrogen raw material (12) enters the second selective adsorption device (6) through the second feed valve (3) to perform the second adsorption of carbon monoxide; and the obtained second product hydrogen is output through the second discharge valve (4) and the product hydrogen output pipeline (13).

24. The system according to claim 23, wherein: The first working state also includes: The second side line front branch pipe desorption valve (9) and the second side line rear branch pipe desorption valve (10) are opened, and the gas circulation pump (15) is connected to the gas in the second selective adsorption device (6), so that the gas in the second selective adsorption device (6) is circulated in sequence through the second discharge valve (4), the second side line front branch pipe desorption valve (9), the gas circulation pump (15) and the second side line rear branch pipe desorption valve (10); The second working state also includes: The first side line front branch pipe desorption valve (7) and the first side line rear branch pipe desorption valve (8) are opened, and the gas circulation pump (15) is connected to the internal gas of the first selective adsorption device (5), so that the gas in the first selective adsorption device (5) is circulated in sequence through the first discharge valve (2), the first side line front branch pipe desorption valve (7), the gas circulation pump (15) and the first side line rear branch pipe desorption valve (8).

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