A heat exchange adsorption system and method for hydrogen purification

Abstract

This application discloses a heat exchange adsorption system and method for hydrogen purification. The heat exchange adsorption system for hydrogen purification includes a first adsorber and a second adsorber. The first adsorber has a first heat exchange tube inside, and the second adsorber has a second heat exchange tube inside. Desorbed gas is introduced into the first heat exchange tube and the second heat exchange tube through the first heat exchange medium inlet and the second heat exchange medium inlet, respectively, to heat the adsorbent and desorb the adsorbed CO and H2S from the adsorbent. This allows the adsorbent to be reused and not consumed, resulting in a long-term stable CO content of less than 0.2 ppm in the obtained hydrogen product. This avoids the problem of CO adsorbing on the platinum electrode, hindering the electrochemical reaction of H2, which would lead to reduced energy conversion efficiency, shortened battery life, or even complete battery deactivation.

Description

Technical Field

[0001] This application belongs to the field of hydrogen production technology, specifically relating to a heat exchange adsorption system and method for hydrogen purification. Background Technology

[0002] Fuel cell technology primarily focuses on the proton exchange membrane fuel cell (PEMFC), which boasts the most mature technology and highest level of industrialization. PEMFCs offer advantages such as high power generation efficiency, environmental friendliness, and a wide availability of hydrogen fuel, making them promising for applications in stationary power plants, vehicle power supplies, portable power sources, and aerospace, and thus attracting significant attention from governments worldwide. However, in PEMFC electrode catalysts, the noble metal Pt supporting the catalyst is highly sensitive to CO and sulfur. Excessive impurities in the hydrogen, particularly C and S compounds, can cause irreversible poisoning of the electrodes. Therefore, the impurity requirements for hydrogen are very stringent. Platinum and palladium electrodes, in particular, exhibit greater CO adsorption than H2 adsorption, causing CO adsorption on the platinum electrode to hinder the electrochemical reaction of H2, reducing energy conversion efficiency, shortening battery life, and even leading to complete deactivation. Hydrogen fuel cells also have extremely high requirements for hydrogen quality; before refueling, the hydrogen must be purified to remove impurities.

[0003] Currently, hydrogen purification in China mainly relies on pressure swing adsorption (PSA). Following industrial hydrogen standards, hydrogen from various sources is purified. However, using traditional PSA to purify raw hydrogen to meet fuel cell requirements is relatively inefficient. While achieving a total sulfur (H2S) content below 4 ppb (parts per billion) is relatively easier, the CO content in hydrogen is difficult to maintain consistently below 0.2 ppm (parts per million) due to adsorbent consumption. There is a lack of more efficient and economical hydrogen purification technology and equipment on the market, particularly the significant challenge of maintaining a consistently low CO content below 0.2 ppm in hydrogen. Summary of the Invention

[0004] To address the problem that existing hydrogen purification processes consume adsorbents, making it difficult to consistently maintain a CO content below 0.2 ppm in the obtained hydrogen, and that platinum, palladium, and other noble metal electrodes exhibit greater CO adsorption than H2 adsorption, causing CO adsorption on platinum electrodes to hinder the electrochemical reaction of H2, thus reducing energy conversion efficiency, shortening battery life, and even causing complete battery deactivation, this application provides a heat exchange adsorption system and method for hydrogen purification.

[0005] In a first aspect of this application, a heat exchange adsorption system for hydrogen purification is provided, comprising a first adsorber and a second adsorber.

[0006] Both the first and second adsorbers are equipped with adsorbents, which are used to adsorb CO and H2S from the raw material hydrogen gas.

[0007] The first adsorber is provided with a first heat exchange tube inside, which is used to heat and desorb the adsorbent inside the first adsorber; the first adsorber is provided with a first raw material gas inlet, a first product gas outlet and a first heat exchange medium inlet on its outer wall, and the first heat exchange medium inlet is connected to the first heat exchange tube.

[0008] The second adsorber is equipped with a second heat exchange tube for heating and desorbing the adsorbent inside the second adsorber; the outer wall of the second adsorber is provided with a second raw material gas inlet, a second product gas outlet and a second heat exchange medium inlet, the second product gas outlet is connected to the first product gas outlet and the second heat exchange medium inlet is connected to the second heat exchange tube.

[0009] During the adsorption process, the first raw material gas inlet and the second raw material gas inlet respectively introduce raw material hydrogen into the first adsorber and the second adsorber. The adsorbent adsorbs CO and H2S, and the resulting product hydrogen flows out from the first product gas outlet and the second product gas outlet.

[0010] During the desorption process, the desorbed gas enters the first heat exchange tube and the second heat exchange tube through the first heat exchange medium inlet and the second heat exchange medium inlet, respectively, to heat the adsorbent and desorb the adsorbed CO and H2S from the adsorbent.

[0011] The adsorption and desorption of the first and second adsorbers are carried out alternately. One of the first product gas outlet and the second product gas outlet supplies a portion of the product hydrogen to the other for purging the desorbed CO and H2S, so that CO and H2S flow out from the first raw material gas inlet and the second raw material gas inlet to the waste gas treatment pipeline.

[0012] In some embodiments, the first raw material gas inlet and the second raw material gas inlet are respectively connected to the hydrogen feed main pipeline through a first feed branch pipe and a second feed branch pipe. A first gas inlet valve is provided on the first feed branch pipe, and a second gas inlet valve is provided on the second feed branch pipe.

[0013] The first product gas outlet and the second product gas outlet are respectively connected to the main product discharge pipeline through the first discharge branch pipe and the second discharge branch pipe. The first discharge branch pipe is equipped with the first gas outlet valve, and the second discharge branch pipe is equipped with the second gas outlet valve. A return pipe is connected between the second discharge branch pipe between the first product gas outlet and the first gas outlet valve and between the second product gas outlet and the second gas outlet valve. A return valve and a reversing valve are installed on the return pipe.

[0014] The first product gas outlet and the second product gas outlet are respectively connected to the main waste gas recovery pipeline through a first waste gas recovery branch pipe and a second waste gas recovery branch pipe. The first waste gas recovery branch pipe is connected to the first discharge branch pipe between the first gas outlet valve and the first product gas outlet, and a first waste gas valve is installed on the first waste gas recovery branch pipe. The second waste gas recovery branch pipe is connected to the second gas outlet valve and a second discharge branch pipe with the same diameter as the second product gas outlet, and a second waste gas valve is installed on the second waste gas recovery branch pipe.

[0015] During the adsorption process, the first waste gas valve and the second waste gas valve are closed, and the first inlet valve, the second inlet valve, the first outlet valve and the second outlet valve are opened. The raw material hydrogen enters the first adsorber and the second adsorber through the first feed branch pipe and the second feed branch pipe respectively, and the product hydrogen flows out of the first adsorber and the second adsorber from the first outlet branch pipe and the second outlet branch pipe respectively.

[0016] During desorption, the reflux valve and the reversing valve open, and the product hydrogen gas generated by the first adsorber enters the second product gas outlet through the first product gas outlet to purge the CO and H2S desorbed by the adsorbent in the second adsorber, so that CO and H2S flow out from the second raw material gas inlet to the waste gas treatment pipeline; or, the product hydrogen gas generated by the second adsorber enters the first product gas outlet through the second product gas outlet to purge the CO and H2S desorbed by the adsorbent in the first adsorber, so that CO and H2S flow out from the first raw material gas inlet to the waste gas treatment pipeline.

[0017] In some embodiments, during the adsorption process, when the adsorbent is saturated, the first inlet valve, the second inlet valve, the first outlet valve, and the second outlet valve are closed, while the first waste gas valve and the second waste gas valve are opened. The gas in the first adsorber and the second adsorber flows out from the first raw material gas inlet and the second raw material gas inlet to the waste gas treatment pipeline, respectively, reducing the pressure in the first adsorber and the second adsorber to a preset pressure threshold.

[0018] In some embodiments, after CO and H2S in the adsorbent are completely desorbed, desorption gas is continued to be introduced into the first heat exchange tube and the second heat exchange tube through the first heat exchange medium inlet and the second heat exchange medium inlet, so as to reduce the temperature in the first adsorber and the second adsorber to a preset adsorption temperature, which is 20 to 40°C.

[0019] In some embodiments, during the desorption process, after the CO and H2S to be desorbed are completely purged into the waste gas treatment pipeline, the first waste gas valve and the second waste gas valve are closed, and one of the first product gas outlet and the second product gas outlet supplies a portion of product hydrogen to the other, causing its internal pressure to rise to a preset adsorption pressure, which is 1-3 MPa.

[0020] In some embodiments, the device further includes a desorbed gas supply device and a desorbed gas recovery device. The first heat exchange medium inlet is connected to the desorbed gas supply device, and a first heat exchange medium outlet is provided on the outer wall of the first adsorber. The first heat exchange medium outlet is connected to the first heat exchange tube and the desorbed gas recovery device respectively, for the purpose of recovering and utilizing the desorbed gas. The second heat exchange medium inlet is connected to the desorbed gas supply device through a second medium inlet branch pipe. The second heat exchange medium outlet is provided on the outer wall of the second adsorber. The second heat exchange medium outlet is connected to the second heat exchange tube and the desorbed gas recovery device respectively, for the purpose of recovering and utilizing the desorbed gas.

[0021] In a second aspect of this application, a heat exchange adsorption method for hydrogen purification is provided, using the heat exchange adsorption system for hydrogen purification described in the first aspect, comprising:

[0022] CO and H2S in the raw hydrogen introduced from the first and second raw gas inlets are adsorbed by an adsorbent, and the resulting product hydrogen flows out from the first and second product gas outlets.

[0023] By introducing desorption gas into the first heat exchange tube and the second heat exchange tube to heat the adsorbent, the adsorbed CO and H2S are desorbed from the adsorbent.

[0024] The adsorption and desorption of the first and second adsorbers are carried out alternately. One of the first product gas outlet and the second product gas outlet delivers a portion of product hydrogen to the other to purge the desorbed CO and H2S, so that CO and H2S flow out from the first raw material gas inlet and the second raw material gas inlet to the waste gas treatment pipeline.

[0025] In some embodiments, after heating the adsorbent by introducing desorption gas into the first and second heat exchange tubes to desorb the adsorbed CO and H2S from the adsorbent, the method further includes: continuing to introduce desorption gas into the first and second heat exchange tubes through the first and second heat exchange medium inlets to reduce the temperature inside the first and second adsorbers to a preset adsorption temperature, which is 20–40°C.

[0026] In some embodiments, after CO and H2S flow out from the first raw material gas inlet and the second raw material gas inlet to the waste gas treatment pipeline, the method further includes: closing the first waste gas valve and the second waste gas valve, and transferring a portion of product hydrogen from one of the first product gas outlet and the second product gas outlet to the other, thereby increasing its internal pressure to a preset adsorption pressure, wherein the preset adsorption pressure is 1-3 MPa.

[0027] In some embodiments, the adsorption of CO and H2S in the raw hydrogen gas introduced from the first raw gas inlet and the second raw gas inlet by the adsorbent includes: when the adsorbent is saturated, the first inlet valve, the second inlet valve, the first outlet valve and the second outlet valve are closed, the first waste gas valve and the second waste gas valve are opened, and the gas in the first adsorber and the second adsorber flows out from the first raw gas inlet and the second raw gas inlet to the waste gas treatment pipeline, respectively, reducing the pressure in the first adsorber and the second adsorber to a preset pressure threshold.

[0028] The heat exchange adsorption system for hydrogen purification provided according to one or more embodiments of this application has the following advantages compared to the prior art:

[0029] Desorption gas is introduced into the first and second heat exchange tubes through the first and second heat exchange medium inlets, respectively, to heat the adsorbent and desorb the adsorbed CO and H2S. This allows the adsorbent to be reused and not consumed, ensuring that the CO content in the resulting hydrogen product remains consistently below 0.2 ppm. This avoids the problem of CO adsorption on the platinum electrode hindering the electrochemical reaction of H2, leading to reduced energy conversion efficiency, shortened battery life, or even complete battery deactivation. The adsorption and desorption of the first and second adsorbers are performed alternately. One of the first and second product gas outlets supplies a portion of the product hydrogen to the other to purge the desorbed CO and H2S, allowing CO and H2S to flow out from the first and second raw material gas inlets to the waste gas treatment pipeline. This allows the adsorption and desorption of the first and second adsorbers to be cyclical, thus facilitating the reuse of the adsorbent. Attached Figure Description

[0030] Figure 1 A schematic diagram of the structure of a heat exchange adsorption system for hydrogen purification is shown in an embodiment of the present invention.

[0031] Figure 2 This invention illustrates a schematic diagram of the structure of the first adsorber in a heat exchange adsorption system for hydrogen purification, as shown in an embodiment of the invention.

[0032] Figure 3 A schematic flowchart of a heat exchange adsorption method for hydrogen purification is shown in an embodiment of the present invention.

[0033] The reference numerals in the above figures are as follows: 100-First Adsorber, 110-Tank, 111-First Heat Exchanger Tube, 112-First Raw Material Gas Inlet, 113-First Product Gas Outlet, 114-First Heat Exchange Medium Inlet, 115-First Heat Exchange Medium Outlet, 116-Lower Part Distributor, 117-Ceramic Ball, 118-Thermometer Port, 119-Ear, 120-Wire Mesh, 121-Hand Hole, 122-Upper Part Distributor, 130-First Inlet Valve, 140-First... 150 - First exhaust gas valve; 200 - Second adsorber; 211 - Second heat exchange tube; 212 - Second raw material gas inlet; 213 - Second product gas outlet; 214 - Second heat exchange medium inlet; 215 - Second heat exchange medium outlet; 230 - Second inlet valve; 240 - Second outlet valve; 250 - Second exhaust gas valve; 300 - reflux valve; 400 - reversing valve; 500 - desorbed gas supply device; 600 - desorbed gas recovery device; 700 - heater. Detailed Implementation

[0034] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0035] Before introducing specific embodiments, several hydrogen purification methods will be briefly described. Hydrogen purification methods mainly include cryogenic separation, adsorption (pressure swing adsorption, temperature swing adsorption), catalytic deoxygenation, and membrane separation. Cryogenic separation, also known as low-temperature separation, utilizes the boiling point difference of different substances to separate other component gases contained in hydrogen through low-temperature liquefaction. This technology is suitable for applications where the hydrogen purification level requirement is not high, but cryogenic separation is a high-energy-consuming separation process. Adsorption is a method that utilizes the different adsorption capacities of adsorbents for adsorbates under different states to achieve adsorption and desorption. Adsorption methods are further divided into pressure swing adsorption (PSA) and temperature swing adsorption (TSA). PSA has advantages such as low energy consumption, high product purity with flexible adjustment, simple process flow, ability to separate multiple gases, high automation, simple operation, and long adsorbent lifespan. Its biggest drawback is low product recovery rate. TSA, on the other hand, utilizes the characteristic that adsorbents have a high adsorption capacity for adsorbates at low temperatures and a low adsorption capacity at high temperatures. A mixed gas is passed through an adsorbent bed at a lower temperature, where impurities are adsorbed. When adsorption becomes saturated, the adsorbent bed loses its adsorption capacity. At this point, the adsorbent bed is heated, and the adsorbed impurities are desorbed, while the adsorbent is regenerated for reuse. Its advantages include high throughput, making it particularly suitable for industrial hydrogen repurification, low operating costs, significant savings in power costs, small footprint, and simple operation. The embodiments in this application employ temperature swing adsorption.

[0036] In the first aspect of this application, reference is made to Figure 1 and Figure 2 As shown, a heat exchange adsorption system for hydrogen purification is provided, including a first adsorber 100 and a second adsorber 200.

[0037] Both the first adsorber 100 and the second adsorber 200 contain adsorbents. These adsorbents adsorb CO and H₂S from the raw hydrogen gas. The adsorbent can be a molecular sieve, which (also known as synthetic zeolite) is a microporous aluminosilicate crystal. It has a basic framework structure composed of silicon-oxygen and aluminum-oxygen tetrahedra, and contains metal cations (such as Na₂O₃) within the crystal lattice. + K + Ca 2+ Li + (etc.) to balance excess negative charge in the crystal. Molecular sieves are materials containing precise and single micropores that can be used to adsorb gases or liquids. Sufficiently small molecules can be adsorbed through the pores, while larger molecules cannot.

[0038] The first adsorber 100 is internally provided with a first heat exchange tube 111 for heating and desorbing the adsorbent inside the first adsorber 100. The outer wall of the first adsorber 100 is provided with a first raw material gas inlet 112, a first product gas outlet 113 and a first heat exchange medium inlet 114, which are connected to the first heat exchange tube 111. The first heat exchange tube 111 is located inside the first adsorber 100 and can directly heat the adsorbent in the first adsorber 100. The first adsorber 100 can also insulate the first heat exchange tube 111, which can achieve energy saving and high efficiency.

[0039] The first adsorber 100 and the second adsorber 200 have the same structure. In this embodiment, the first adsorber 100 is used as an example for illustration:

[0040] like Figure 2 As shown, the first adsorber 100 includes a sealed tank 110, a first raw material gas inlet 112 located above the top of the tank 110, a first product gas outlet 113 located below the bottom of the tank 110, a first heat exchange tube 111 located inside the tank 110, and its two ends connected to a first heat exchange medium inlet 114 and a first heat exchange medium outlet 115, respectively. The adsorbent is located inside the tank 110, with the first heat exchange medium inlet 114 located above the side wall of the tank 110, and the first heat exchange medium outlet 115 located below the side wall of the tank 110. The bottom of the inner wall of the tank 110 is also located inside the tank 110. The tank 110 is equipped with a lower part distributor 116, which is connected to the first raw material gas inlet 112. The bottom of the inner wall of the tank 110 is provided with ceramic balls 117. The outer wall of the tank 110 is provided with a thermometer port 118 for installing a thermometer. The outer wall of the tank 110 is provided with an ear seat 119 for installing and fixing the first adsorber 100. The top of the inner wall of the tank 110 is provided with a wire mesh 120, on which the ceramic balls 117 are supported. The top of the tank 110 is provided with a hand hole 121, which is connected to the first product gas outlet 113. The upper part distributor 122 is provided in the hand hole 121.

[0041] The second adsorber 200 is internally equipped with a second heat exchange tube 211 for heating and desorbing the adsorbent inside the second adsorber 200. The outer wall of the second adsorber 200 is provided with a second raw material gas inlet 212, a second product gas outlet 213, and a second heat exchange medium inlet 214. The second product gas outlet 213 is connected to the first product gas outlet 113, and the second heat exchange medium inlet 214 is connected to the second heat exchange tube 211. The second heat exchange tube 211 is located inside the second adsorber 200 and can directly heat the adsorbent in the second adsorber 200. The second adsorber 200 can also insulate the second heat exchange tube 211, which can achieve energy saving and high efficiency.

[0042] During the adsorption process, the first raw material gas inlet 112 and the second raw material gas inlet 212 respectively introduce raw material hydrogen into the first adsorber 100 and the second adsorber 200. The adsorbent adsorbs CO and H2S, and the resulting product hydrogen flows out from the first product gas outlet 113 and the second product gas outlet 213.

[0043] During the desorption process, the desorption gas enters the first heat exchange tube 111 and the second heat exchange tube 211 through the first heat exchange medium inlet 114 and the second heat exchange medium inlet 214, respectively, to heat the adsorbent and desorb the adsorbed CO and H2S from the adsorbent. The desorption gas can be the tail gas generated from other processes, or an inert gas such as nitrogen. The desorption gas is preheated before entering the first heat exchange tube 111 and the second heat exchange tube 211. Here, the adsorbent is heated to 160-200°C by the desorption gas to desorb CO and H2S from the adsorbent.

[0044] The adsorption and desorption of the first adsorber 100 and the second adsorber 200 are carried out alternately. The first product gas outlet 113 and the second product gas outlet 213, one of which supplies part of the product hydrogen to the other, is used to purge the desorbed CO and H2S, so that CO and H2S flow out from the first raw material gas inlet 112 and the second raw material gas inlet 212 to the waste gas treatment pipeline.

[0045] This application provides a heat exchange adsorption system for hydrogen purification. Desorbed gas enters the first heat exchange tube 111 and the second heat exchange tube 211 through the first heat exchange medium inlet 114 and the second heat exchange medium inlet 214, respectively, to heat the adsorbent and desorb the adsorbed CO and H2S from the adsorbent. This allows the adsorbent to be reused and not consumed, ensuring that the CO content in the obtained hydrogen is consistently below 0.2 ppm over a long period. This avoids CO adsorption on the platinum electrode hindering the electrochemical reaction of H2 and thus reducing energy conversion efficiency. This addresses the issues of low efficiency, shortened battery life, and even complete battery deactivation. The adsorption and desorption processes of the first adsorber 100 and the second adsorber 200 alternate. One of the first product gas outlets 113 and 213 supplies a portion of the product hydrogen to the other for purging the desorbed CO and H2S. This allows CO and H2S to flow from the first raw material gas inlet 112 and the second raw material gas inlet 212 to the waste gas treatment pipeline, enabling the adsorption and desorption processes of the first adsorber 100 and the second adsorber 200 to be cyclical, thus facilitating the reuse of the adsorbent.

[0046] In some embodiments, the first raw material gas inlet 112 and the second raw material gas inlet 212 are respectively connected to the hydrogen feed main pipeline through the first feed branch pipe and the second feed branch pipe. The first feed branch pipe is provided with a first air inlet valve 130 and the second feed branch pipe is provided with a second air inlet valve 230.

[0047] The first product gas outlet 113 and the second product gas outlet 213 are respectively connected to the main product discharge pipeline through the first discharge branch pipe and the second discharge branch pipe. The first discharge branch pipe is equipped with the first gas outlet valve 140, and the second discharge branch pipe is equipped with the second gas outlet valve 240. A return pipe is connected between the second discharge branch pipe between the first product gas outlet 113 and the first gas outlet valve 140 and the first discharge branch pipe between the second product gas outlet 213 and the second gas outlet valve 240. A return valve 300 and a reversing valve 400 are installed on the return pipe.

[0048] The first product gas outlet 113 and the second product gas outlet 213 are respectively connected to the main waste gas recovery pipeline through the first waste gas recovery branch pipe and the second waste gas recovery branch pipe. The first waste gas recovery branch pipe is connected to the first discharge branch pipe between the first gas outlet valve 140 and the first product gas outlet 113. A first waste gas valve 150 is installed on the first waste gas recovery branch pipe. The second waste gas recovery branch pipe is connected to the second gas outlet valve 240 and the second discharge branch pipe with the same diameter as the second product gas outlet 213. A second waste gas valve 250 is installed on the second waste gas recovery branch pipe.

[0049] During the adsorption process, the first waste gas valve 150 and the second waste gas valve 250 are closed, and the first inlet valve 130, the second inlet valve 230, the first outlet valve 140 and the second outlet valve 240 are opened. The raw material hydrogen enters the first adsorber 100 and the second adsorber 200 through the first feed branch pipe and the second feed branch pipe respectively, and the product hydrogen flows out of the first adsorber 100 and the second adsorber 200 through the first outlet branch pipe and the second outlet branch pipe respectively.

[0050] During the desorption process, the reflux valve 300 and the reversing valve 400 are opened. The product hydrogen gas generated by the first adsorber 100 enters the second product gas outlet 213 through the first product gas outlet 113 to purge the CO and H2S desorbed by the adsorbent in the second adsorber 200, so that the CO and H2S flow out from the second raw material gas inlet 212 to the waste gas treatment pipeline; or, the product hydrogen gas generated by the second adsorber 200 enters the first product gas outlet 113 through the second product gas outlet 213 to purge the CO and H2S desorbed by the adsorbent in the first adsorber 100, so that the CO and H2S flow out from the first raw material gas inlet 112 to the waste gas treatment pipeline.

[0051] In this embodiment, by alternating adsorption and desorption by the first adsorber 100 and the second adsorber 200, continuous input of raw material hydrogen and continuous output of product hydrogen can be achieved.

[0052] In some embodiments, during the adsorption process, when the adsorbent becomes saturated, the first inlet valve 130, the second inlet valve 230, the first outlet valve 140, and the second outlet valve 240 are closed, while the first waste gas valve 150 and the second waste gas valve 250 are opened. The gases in the first adsorber 100 and the second adsorber 200 flow out from the first raw material gas inlet 112 and the second raw material gas inlet 212, respectively, to the waste gas treatment pipeline, reducing the pressure in the first adsorber 100 and the second adsorber 200 to a preset pressure threshold. The adsorbent loading amount and adsorption time are designed according to the gas composition; adsorption saturation is considered achieved when the adsorption time is reached. The gases in the first adsorber 100 and the second adsorber 200 flow out from the first raw material gas inlet 112 and the second raw material gas inlet 212 to the waste gas treatment pipeline, respectively, to achieve reverse pressure release and reduce the pressure to a preset pressure threshold, which is conducive to the desorption of impurities. Reverse pressure release also helps the gas impurities in the first adsorber 100 and the second adsorber 200 to be desorbed from the bottom of the first adsorber 100 and the second adsorber 200 more quickly, which is beneficial to prevent the upper adsorbent from being contaminated.

[0053] In some embodiments, after CO and H2S are completely desorbed from the adsorbent, desorption gas is continued to be introduced into the first heat exchange tube 111 and the second heat exchange tube 211 through the first heat exchange medium inlet 114 and the second heat exchange medium inlet 214 to lower the temperature inside the first adsorber 100 and the second adsorber 200 to a preset adsorption temperature, which is 20-40°C. The desorption gas introduced here is pre-cooled. By introducing the low-temperature desorption gas into the first heat exchange tube 111 and the second heat exchange tube 211, the temperature inside the first adsorber 100 and the second adsorber 200 is lowered to the preset adsorption temperature, preparing for the next cycle of adsorption treatment.

[0054] In some embodiments, during the desorption process, after the CO and H2S to be desorbed are completely purged into the waste gas treatment pipeline, the first waste gas valve 150 and the second waste gas valve 250 are closed. One of the first product gas outlets 113 and 213 supplies a portion of product hydrogen to the other, increasing its internal pressure to a preset adsorption pressure, which is 1-3 MPa. Through the first and second adsorption towers, the supply of product hydrogen from one to the other increases the internal pressure of the other to the preset adsorption pressure, preparing it for the next cycle of adsorption treatment.

[0055] In some embodiments, the heat exchange adsorption system for hydrogen purification further includes a desorbed gas supply device 500 and a desorbed gas recovery device 600. A first heat exchange medium inlet 114 is connected to the desorbed gas supply device 500. A first heat exchange medium outlet 115 is also provided on the outer wall of the first adsorber 100. The first heat exchange medium outlet 115 is connected to the first heat exchange tube 111 and the desorbed gas recovery device 600 respectively for the recovery and reuse of desorbed gas. A second heat exchange medium inlet 214 is connected to the desorbed gas supply device 500 through a second medium inlet branch pipe. A second heat exchange medium outlet 215 is also provided on the outer wall of the second adsorber 200. The second heat exchange medium outlet 215 is connected to the second heat exchange tube 211 and the desorbed gas recovery device 600 respectively for the recovery and reuse of desorbed gas. In actual use, a heater 700 is provided between the desorption gas supply device 500 and the first heat exchange medium inlet 114. When high-temperature desorption gas is required to heat the adsorbent, the heater 700 is turned on to heat the desorption gas. When the first adsorber 100 is cooled, the heater 700 is turned off and desorption gas at room temperature is introduced.

[0056] In the second aspect of this application, reference is made to... Figure 3 As shown, a heat exchange adsorption method for hydrogen purification is provided, using the heat exchange adsorption system for hydrogen purification according to the first aspect embodiment, comprising:

[0057] Step S1: CO and H2S in the raw hydrogen introduced from the first raw gas inlet 112 and the second raw gas inlet 212 are adsorbed by an adsorbent, and the resulting product hydrogen flows out from the first product gas outlet 113 and the second product gas outlet 213.

[0058] Step S2: By introducing desorption gas into the first heat exchange tube 111 and the second heat exchange tube 211, the adsorbent is heated to desorb the adsorbed CO and H2S from the adsorbent.

[0059] Step S3: The adsorption and desorption of the first adsorber 100 and the second adsorber 200 are carried out alternately. The first product gas outlet 113 and the second product gas outlet 213, one of them delivers part of the product hydrogen to the other to purge the desorbed CO and H2S, so that CO and H2S flow out from the first raw material gas inlet 112 and the second raw material gas inlet 212 to the waste gas treatment pipeline.

[0060] This embodiment provides a heat exchange adsorption method for hydrogen purification. By introducing desorption gas into the first heat exchange tube 111 and the second heat exchange tube 211 to heat the adsorbent, the adsorbed CO and H2S are desorbed from the adsorbent, allowing the adsorbent to be reused and not consumed. This ensures that the CO content in the obtained hydrogen remains consistently below 0.2 ppm, avoiding the problem of CO adsorption on the platinum electrode hindering the electrochemical reaction of H2, leading to reduced energy conversion efficiency, shortened battery life, or even complete battery deactivation. The adsorption and desorption of the first adsorber 100 and the second adsorber 200 alternate. One of the first product gas outlet 113 and the second product gas outlet 213 supplies a portion of product hydrogen to the other for purging the desorbed CO and H2S, so that CO and H2S flow out from the first raw material gas inlet 112 and the second raw material gas inlet 212 to the waste gas treatment pipeline. This allows the adsorption and desorption of the first adsorber 100 and the second adsorber 200 to be cyclical, thus facilitating the reuse of the adsorbent.

[0061] In some embodiments, after step S2 heats the adsorbent by introducing desorption gas into the first heat exchange tube 111 and the second heat exchange tube 211 to desorb the adsorbed CO and H2S, the process further includes: continuing to introduce desorption gas into the first heat exchange tube 111 and the second heat exchange tube 211 through the first heat exchange medium inlet 114 and the second heat exchange medium inlet 214 to lower the temperature inside the first adsorber 100 and the second adsorber 200 to a preset adsorption temperature, which is 20–40°C. The desorption gas introduced here is pre-cooled; by introducing the low-temperature desorption gas into the first heat exchange tube 111 and the second heat exchange tube 211, the temperature inside the first adsorber 100 and the second adsorber 200 is lowered to the preset adsorption temperature, preparing for the next cycle of adsorption treatment.

[0062] In some embodiments, after CO and H2S flow from the first raw material gas inlet 112 and the second raw material gas inlet 212 to the waste gas treatment pipeline in step S3, the method further includes: closing the first waste gas valve 150 and the second waste gas valve 250; and supplying a portion of product hydrogen from one of the first product gas outlet 113 and the second product gas outlet 213 to the other, thereby increasing the internal pressure of the latter to a preset adsorption pressure, which is 1-3 MPa. Through the first adsorption tower and the second adsorption tower, the supply of a portion of product hydrogen from one to the other increases the internal pressure of the latter to the preset adsorption pressure, preparing it for the next cycle of adsorption treatment.

[0063] In some embodiments, step S1, where CO and H2S in the raw hydrogen gas introduced from the first raw gas inlet 112 and the second raw gas inlet 212 are adsorbed by an adsorbent, includes: when the adsorbent is saturated, the first inlet valve 130, the second inlet valve 230, the first outlet valve 140, and the second outlet valve 240 are closed, and the first waste gas valve 150 and the second waste gas valve 250 are opened. The gases in the first adsorber 100 and the second adsorber 200 flow out from the first raw gas inlet 112 and the second raw gas inlet 212 to the waste gas treatment pipeline, respectively, reducing the pressure in the first adsorber 100 and the second adsorber 200 to a preset pressure threshold. The adsorbent loading amount and adsorption time are designed according to the gas composition, and adsorption saturation is considered achieved when the adsorption time is reached. The gases in the first adsorber 100 and the second adsorber 200 flow out from the first raw material gas inlet 112 and the second raw material gas inlet 212 to the waste gas treatment pipeline, respectively, to achieve reverse pressure release and reduce the pressure to a preset pressure threshold, which is conducive to the desorption of impurities. Reverse pressure release also helps the gas impurities in the tower to be desorbed from the bottom of the tower more quickly, and helps the adsorbent in the upper layer to not be contaminated.

[0064] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0065] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0066] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0067] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0068] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A heat exchange adsorption system for hydrogen purification, characterized in that, Includes a first adsorber and a second adsorber; Both the first and second adsorbers are equipped with adsorbents, which are used to adsorb CO and H2S from the raw material hydrogen gas. The adsorbent is a molecular sieve; The first adsorber is provided with a first heat exchange tube inside, which is used to heat and desorb the adsorbent inside the first adsorber; the first adsorber is provided with a first raw material gas inlet, a first product gas outlet and a first heat exchange medium inlet on its outer wall, and the first heat exchange medium inlet is connected to the first heat exchange tube. The second adsorber is equipped with a second heat exchange tube for heating and desorbing the adsorbent inside the second adsorber; the outer wall of the second adsorber is provided with a second raw material gas inlet, a second product gas outlet and a second heat exchange medium inlet, the second product gas outlet is connected to the first product gas outlet and the second heat exchange medium inlet is connected to the second heat exchange tube. During the adsorption process, the first raw material gas inlet and the second raw material gas inlet respectively introduce raw material hydrogen into the first adsorber and the second adsorber. The adsorbent adsorbs CO and H2S, and the resulting product hydrogen flows out from the first product gas outlet and the second product gas outlet. During the desorption process, the desorbed gas enters the first heat exchange tube and the second heat exchange tube through the first heat exchange medium inlet and the second heat exchange medium inlet, respectively, to heat the adsorbent and desorb the adsorbed CO and H2S from the adsorbent. The adsorption and desorption of the first and second adsorbers are carried out alternately. One of the first product gas outlet and the second product gas outlet supplies a portion of the product hydrogen to the other for purging the desorbed CO and H2S, so that CO and H2S flow out from the first raw material gas inlet and the second raw material gas inlet to the waste gas treatment pipeline.

2. The heat exchange adsorption system for hydrogen purification according to claim 1, characterized in that, The first raw material gas inlet and the second raw material gas inlet are respectively connected to the hydrogen feed main pipeline through the first feed branch pipe and the second feed branch pipe. The first feed branch pipe is equipped with a first gas inlet valve, and the second feed branch pipe is equipped with a second gas inlet valve. The first product gas outlet and the second product gas outlet are respectively connected to the main product discharge pipeline through the first discharge branch pipe and the second discharge branch pipe. The first discharge branch pipe is equipped with the first gas outlet valve, and the second discharge branch pipe is equipped with the second gas outlet valve. A return pipe is connected between the second discharge branch pipe between the first product gas outlet and the first gas outlet valve and between the second product gas outlet and the second gas outlet valve. A return valve and a reversing valve are installed on the return pipe. The first product gas outlet and the second product gas outlet are respectively connected to the main waste gas recovery pipeline through a first waste gas recovery branch pipe and a second waste gas recovery branch pipe. The first waste gas recovery branch pipe is connected to the first discharge branch pipe between the first gas outlet valve and the first product gas outlet, and a first waste gas valve is installed on the first waste gas recovery branch pipe. The second waste gas recovery branch pipe is connected to the second gas outlet valve and a second discharge branch pipe with the same diameter as the second product gas outlet, and a second waste gas valve is installed on the second waste gas recovery branch pipe. During the adsorption process, the first waste gas valve and the second waste gas valve are closed, and the first inlet valve, the second inlet valve, the first outlet valve and the second outlet valve are opened. The raw material hydrogen enters the first adsorber and the second adsorber through the first feed branch pipe and the second feed branch pipe respectively, and the product hydrogen flows out of the first adsorber and the second adsorber from the first outlet branch pipe and the second outlet branch pipe respectively. During desorption, the reflux valve and the reversing valve open, and the product hydrogen gas generated by the first adsorber enters the second product gas outlet through the first product gas outlet to purge the CO and H2S desorbed by the adsorbent in the second adsorber, so that CO and H2S flow out from the second raw material gas inlet to the waste gas treatment pipeline; or, the product hydrogen gas generated by the second adsorber enters the first product gas outlet through the second product gas outlet to purge the CO and H2S desorbed by the adsorbent in the first adsorber, so that CO and H2S flow out from the first raw material gas inlet to the waste gas treatment pipeline.

3. The heat exchange adsorption system for hydrogen purification according to claim 2, characterized in that, During the adsorption process, when the adsorbent is saturated, the first inlet valve, the second inlet valve, the first outlet valve, and the second outlet valve are closed, while the first waste gas valve and the second waste gas valve are opened. The gas in the first adsorber and the second adsorber flows out from the first raw material gas inlet and the second raw material gas inlet to the waste gas treatment pipeline, respectively, reducing the pressure in the first adsorber and the second adsorber to a preset pressure threshold.

4. The heat exchange adsorption system for hydrogen purification according to claim 3, characterized in that, After CO and H2S in the adsorbent are completely desorbed, desorption gas is continued to be introduced into the first heat exchange tube and the second heat exchange tube through the first heat exchange medium inlet and the second heat exchange medium inlet, so as to reduce the temperature in the first adsorber and the second adsorber to a preset adsorption temperature, which is 20~40℃.

5. The heat exchange adsorption system for hydrogen purification according to claim 1, characterized in that, During the desorption process, after the CO and H2S to be desorbed are completely purged into the waste gas treatment pipeline, the first waste gas valve and the second waste gas valve are closed. One of the first product gas outlet and the second product gas outlet supplies a portion of product hydrogen to the other, causing its internal pressure to rise to the preset adsorption pressure, which is 1-3 MPa.

6. The heat exchange adsorption system for hydrogen purification according to claim 4, characterized in that, It also includes a desorbed gas supply device and a desorbed gas recovery device. The first heat exchange medium inlet is connected to the desorbed gas supply device. The outer wall of the first adsorber is also provided with a first heat exchange medium outlet, which is connected to the first heat exchange tube and the desorbed gas recovery device for recycling the desorbed gas. The second heat exchange medium inlet is connected to the desorbed gas supply device through a second medium inlet branch pipe. The outer wall of the second adsorber is also provided with a second heat exchange medium outlet, which is connected to the second heat exchange tube and the desorbed gas recovery device for recycling the desorbed gas.

7. A heat exchange adsorption method for hydrogen purification, using the heat exchange adsorption system for hydrogen purification according to any one of claims 1-6, characterized in that, include: CO and H2S in the raw hydrogen introduced from the first and second raw gas inlets are adsorbed by an adsorbent, and the resulting product hydrogen flows out from the first and second product gas outlets. By introducing desorption gas into the first heat exchange tube and the second heat exchange tube to heat the adsorbent, the adsorbed CO and H2S are desorbed from the adsorbent. The adsorption and desorption of the first and second adsorbers are carried out alternately. One of the first product gas outlet and the second product gas outlet delivers a portion of product hydrogen to the other to purge the desorbed CO and H2S, so that CO and H2S flow out from the first raw material gas inlet and the second raw material gas inlet to the waste gas treatment pipeline.

8. The heat exchange adsorption method for hydrogen purification according to claim 7, characterized in that, After heating the adsorbent by introducing desorption gas into the first and second heat exchange tubes to desorb the adsorbed CO and H2S, the method further includes: continuing to introduce desorption gas into the first and second heat exchange tubes through the first and second heat exchange medium inlets to reduce the temperature inside the first and second adsorbers to a preset adsorption temperature, which is 20~40℃.

9. The heat exchange adsorption method for hydrogen purification according to claim 7, characterized in that, After CO and H2S flow out from the first raw material gas inlet and the second raw material gas inlet to the waste gas treatment pipeline, the process further includes: closing the first waste gas valve and the second waste gas valve, and transferring a portion of product hydrogen from the first product gas outlet and the second product gas outlet to the other, thereby increasing the internal pressure to a preset adsorption pressure, wherein the preset adsorption pressure is 1-3 MPa.

10. The heat exchange adsorption method for hydrogen purification according to claim 7, characterized in that, The adsorption of CO and H2S in the raw hydrogen gas introduced from the first raw gas inlet and the second raw gas inlet by the adsorbent includes: when the adsorbent is saturated, the first inlet valve, the second inlet valve, the first outlet valve and the second outlet valve are closed, and the first waste gas valve and the second waste gas valve are opened. The gas in the first adsorber and the second adsorber flows out from the first raw gas inlet and the second raw gas inlet to the waste gas treatment pipeline, respectively, and the pressure in the first adsorber and the second adsorber is reduced to a preset pressure threshold.

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