Ammonia decomposition hydrogen production system with palladium-containing membrane internals and application of ammonia decomposition hydrogen production system

Abstract

The ammonia decomposition hydrogen production system comprises a liquid ammonia tank, a vaporizer, a first heat exchanger, a second heat exchanger and a palladium membrane internal component reactor, the liquid ammonia tank is communicated with the vaporizer, and the vaporizer is further communicated with the first heat exchanger and the second heat exchanger at the same time; the palladium membrane internal component reactor comprises an ammonia gas inlet, a hydrogen gas outlet, a plurality of decomposed gas outlets, and a decomposition interval and a separation interval which are communicated with each other, and the ammonia gas inlet is communicated with the decomposition interval; the hydrogen outlet and the plurality of decomposed gas outlets are communicated with the separation section; a palladium membrane internal component is arranged in the separation section; the palladium membrane internal component is communicated with the hydrogen outlet; the multiple decomposed gas outlets communicate with the first heat exchanger simultaneously, the hydrogen outlet communicates with the second heat exchanger, and a vacuum pump is arranged between the hydrogen outlet and the second heat exchanger and communicates with the hydrogen outlet. The ammonia decomposition hydrogen production system of the palladium-containing membrane internal component realizes integration and miniaturization of the system, saves additional equipment investment, and reduces the cost of the hydrogen production system.

Description

Technical Field

[0001] The invention relates to the technical field of ammonia decomposition hydrogen production equipment, and in particular to an ammonia decomposition hydrogen production system with built-in palladium membrane internal components for a proton exchange membrane fuel cell. Background Art

[0002] In the hydrogen energy industry, ammonia decomposition hydrogen production technology has attracted widespread attention due to its high efficiency, safety and low cost. Traditional hydrogen production methods are not only costly, but also have safety hazards. Ammonia is a hydrogen-rich carrier, and liquid ammonia is easy to store and transport. Decomposing ammonia to produce hydrogen is a safe and efficient hydrogen production solution. The ammonia decomposition reaction is controlled by thermodynamic equilibrium. Even if a high-efficiency catalyst is used in a fixed bed reactor, the complete conversion of ammonia cannot be achieved. In the application of proton exchange membrane fuel cells, a very small amount of ammonia will also dissolve in the proton exchange membrane. The generated NH will lead to a decrease in the proton transfer rate, thereby greatly reducing the working efficiency of the proton exchange membrane fuel cell. There are some uses of pure hydrogen as raw material. The fuel cell has the highest power generation efficiency when the feed gas is pure ammonia, and the maximum concentration of hydrogen in the ammonia decomposition reaction product with pure ammonia as raw material is only 75%; the "hydrogen-nitrogen-residual ammonia" mixed gas produced by the ammonia decomposition device cannot be directly transported to the fuel cell power generation unit, and the hydrogen in the mixed gas must be enriched, and the membrane separation recovery rate is more than 90%; the existing ammonia hydrogen production device can only produce a hydrogen-nitrogen mixed gas containing a small amount of ammonia. If pure hydrogen is required, an additional temperature swing adsorption device (TSA) is required to adsorb a small amount of residual ammonia; and a pressure swing adsorption (PSA) is required to separate hydrogen and nitrogen; the traditional ammonia decomposition hydrogen production system involves a large number of equipment, high energy consumption, high production cost and poor separation effect.

[0003] Chinese patent CN115672194A discloses a vanadium alloy composite membrane reactor for ammonia decomposition, hydrogen production and separation, comprising a reactor shell, a vanadium alloy thin-walled tube composite membrane and a heating assembly arranged in the reactor shell, and the hydrogen outlet of the reactor is connected to the vanadium alloy thin-walled tube composite membrane. The membrane reactor of the present invention adopts a vanadium alloy thin-walled tube with high hydrogen permeability to replace the traditional palladium and its alloy tubes, integrating ammonia decomposition, hydrogen separation and heating, thereby improving the ammonia conversion rate and hydrogen purification efficiency; however, the temperature utilization rate of the composite membrane reactor in the ammonia decomposition process is not high, and the temperature inside the reactor cannot be evenly and effectively distributed and controlled, and there is a large energy consumption during the use of the system, especially in the case of large air volume. Summary of the invention

[0004] In view of the defects of high energy consumption, high production cost and poor separation effect of traditional hydrogen separation equipment in the prior art, and uneven temperature distribution and poor controllability of reactors containing composite membranes, an ammonia decomposition and hydrogen production system containing palladium membrane internal components suitable for proton exchange membrane fuel cells is provided, which has good hydrogen purification effect, high ammonia decomposition efficiency, low system energy consumption, uniform temperature distribution and good temperature controllability.

[0005] In view of the defects of high energy consumption, high production cost and poor separation effect of traditional hydrogen separation equipment in the prior art, and uneven temperature distribution and poor controllability of reactors containing composite membranes, an ammonia decomposition and hydrogen production system containing palladium membrane internal components suitable for proton exchange membrane fuel cells is provided, which has good hydrogen purification effect, high ammonia decomposition efficiency, low system energy consumption, uniform temperature distribution and good temperature controllability.

[0006] The technical solution adopted by the present invention to solve the technical problem is: an ammonia decomposition hydrogen production system containing a palladium membrane internal component, comprising a liquid ammonia tank, a vaporizer, a first heat exchanger, a second heat exchanger and a palladium membrane internal component reactor: the liquid ammonia tank is connected to the vaporizer, and the vaporizer is also connected to the first heat exchanger and the second heat exchanger at the same time; a part of the ammonia gas after vaporization is passed into the first heat exchanger, and another part of the ammonia gas after vaporization is passed into the second heat exchanger; the palladium membrane internal component reactor comprises an ammonia inlet, a hydrogen outlet, a plurality of decomposition gas outlets, and a connected decomposition section and a separation section, the decomposition section is located above the separation section, and the ammonia inlet is connected to the decomposition section. The separation interval is connected; the hydrogen outlet and multiple decomposition gas outlets are all connected to the separation interval; the hydrogen outlet is located on the lower surface of the separation interval; a palladium membrane inner component is fixed inside the separation interval, the structure of the palladium membrane inner component corresponds to the structure of the decomposition interval, one end of the palladium membrane inner component is a closed structure, and the other end of the palladium membrane inner component is an open structure, and one end of the palladium membrane inner component with the open structure is fixed on the lower surface of the separation interval and is connected to the hydrogen outlet; multiple decomposition gas outlets are simultaneously connected to the first heat exchanger, the hydrogen outlet is connected to the second heat exchanger, a vacuum pump is arranged between the hydrogen outlet and the second heat exchanger, and the vacuum pump is connected to the hydrogen outlet.

[0007] Furthermore, a first valve is provided between the liquid ammonia tank and the vaporizer, a three-way valve is provided at the outlet of the vaporizer, the outlet of the vaporizer is connected to one of the interfaces of the three-way valve, and the other two interfaces of the three-way valve are respectively connected to the first heat exchanger and the second heat exchanger.

[0008] Furthermore, the decomposition zone is located above the separation zone, a plurality of baffles are arranged at intervals on the inner wall of the decomposition zone, the plurality of baffles are arranged around the inner wall of the decomposition zone, and the interior of the decomposition zone is filled with an ammonia decomposition catalyst; the ammonia inlet is located directly above the decomposition zone.

[0009] Furthermore, a first filter screen is provided at one end of the decomposition zone close to the separation zone, a plurality of openings are provided on the first filter screen, an outer edge of the first filter screen is connected to an inner wall of the decomposition zone, and the first filter screen is made of nickel metal.

[0010] Furthermore, a first annular heating element is provided on the outside of the decomposition zone, and the cross-sectional shape of the first annular heating element corresponds to the cross-sectional shape of the decomposition zone; a second annular heating element is provided on the outer wall of the separation zone, and the cross-sectional shape of the second annular heating element corresponds to the cross-sectional shape of the separation zone.

[0011] Furthermore, a second filter screen is sleeved on the outer wall of the palladium membrane inner component, and a plurality of through holes are opened on the second filter screen. The outer wall of the second filter screen is connected to the inner wall of the separation zone. The second filter screen is located above the hydrogen outlet and a plurality of decomposition gas outlets, and the second filter screen is made of nickel metal.

[0012] Furthermore, the palladium membrane internal component passes through the second filter screen and is communicated with the hydrogen outlet, and the palladium membrane internal component passes through the second filter screen and is communicated with the hydrogen outlet, and the separation interval is filled with an ammonia decomposition catalyst.

[0013] Furthermore, one of the fluid outlets of the first heat exchanger is connected to the vaporizer, a burner is arranged between one of the fluid outlets of the first heat exchanger and the vaporizer, a second valve is arranged between the first heat exchanger and the burner, and a third valve is arranged between the burner and the vaporizer.

[0014] Furthermore, the second heat exchanger is connected to the ammonia inlet, a fourth valve is provided between the vacuum pump and the second heat exchanger, a fifth valve is provided between the second heat exchanger and the ammonia inlet, the second heat exchanger can exchange heat between the hydrogen introduced from the vacuum pump and the ammonia vaporized by the vaporizer, and a sixth valve is provided at the end of the second heat exchanger for discharging hydrogen.

[0015] Application of an ammonia decomposition hydrogen production system containing palladium membrane internal components: The ammonia decomposition hydrogen production system containing palladium membrane internal components is used for proton exchange membrane fuel cells.

[0016] The ammonia decomposition hydrogen production system containing palladium membrane internal components described in the present invention can avoid repeated purging steps compared to the traditional ammonia hydrogen production system that uses pressure swing adsorption to purify hydrogen; it has a high hydrogen recovery rate, low hydrogen loss during operation, and has the advantages of simple operation, higher adaptability, lower cost and higher recovery rate; by effectively combining ammonia decomposition and ammonia separation, the overall integration of the system is improved, the layout of system components is simplified, and it is more in line with the requirements of on-site hydrogen production from ammonia decomposition; the use of multi-layer palladium membranes to separate and purify hydrogen can make the chemical equilibrium proceed in the direction of generating product hydrogen, and can also prolong the reaction time between reactants and catalysts by reducing the flow rate. The contact time is conducive to the further occurrence of the reaction; and the temperature and gas can be concentrated during the reaction, reducing the defects caused by uneven temperature distribution during the reaction. On the basis of uniform temperature distribution, multiple heat exchangers are combined to achieve effective use of temperature, which also helps to promote the decomposition reaction of ammonia, improve the energy utilization rate of the overall system, hydrogen production and hydrogen purity, and effectively realize the operation of proton exchange membrane fuel cells using liquid ammonia as raw material, overcoming the defects of existing pure hydrogen storage and transportation with high risks; the ammonia decomposition hydrogen production system containing palladium membrane internals realizes the integration and miniaturization of the system, while saving additional equipment investment and reducing the operating cost of hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a schematic structural diagram of an ammonia decomposition hydrogen production system containing a palladium membrane internal component according to the present invention; Figure 2 It is a structural schematic diagram of a palladium membrane internal component reactor of an ammonia decomposition hydrogen production system containing a palladium membrane internal component according to the present invention; Figure 3 It is a structural cross-sectional view of a palladium membrane internal component reactor of an ammonia decomposition hydrogen production system containing a palladium membrane internal component according to the present invention; Figure 4 It is a schematic structural diagram of a first filter screen in a palladium membrane internal component reactor of an ammonia decomposition hydrogen production system containing a palladium membrane internal component according to the present invention; Figure 5 The present invention is a schematic structural diagram of a second filter screen in a palladium membrane internal component reactor of an ammonia decomposition hydrogen production system containing a palladium membrane internal component.

[0019] 1-liquid ammonia tank, 11-first valve, 12-three-way valve, 13-second valve, 14-third valve, 15-fourth valve, 16-sixth valve, 17-sixth valve, 2-vaporizer, 3-first heat exchanger, 4-second heat exchanger, 5-palladium membrane internal component reactor, 51-ammonia inlet, 521-hydrogen outlet, 522-decomposition gas outlet, 53-decomposition interval, 54-separation interval, 55-baffle, 57-first filter, 561-first annular heating element, 562-second annular heating element, 58-second filter 59-palladium membrane internal component, 591-first palladium membrane, 592-second palladium membrane, 6-vacuum pump, 7-burner. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] like Figure 1 to Figure 5 As shown, an ammonia decomposition hydrogen production system containing a palladium membrane internal component of the present invention comprises a liquid ammonia tank 1, a vaporizer 2, a first heat exchanger 3, a second heat exchanger 4 and a palladium membrane internal component reactor 5: the liquid ammonia tank 1 is in communication with the vaporizer 2, and the vaporizer 2 is also in communication with the first heat exchanger 3 and the second heat exchanger 4 at the same time; a part of the ammonia gas after vaporization is passed into the first heat exchanger 3, and another part of the ammonia gas after vaporization is passed into the second heat exchanger 4; the palladium membrane internal component reactor 5 comprises an ammonia inlet 51, a hydrogen outlet 521, a plurality of decomposition gas outlets 522, and a connected decomposition interval 53 and a separation interval 54, the decomposition interval 53 is located above the separation interval 54, and the ammonia inlet 51 is in communication with the decomposition interval 53; the hydrogen outlet 521 and the plurality of decomposition gas outlets 522 are all connected to the separation interval 54; the hydrogen outlet 521 is located on the lower surface of the separation interval 54; a palladium membrane inner component 59 is fixed inside the separation interval 54, the structure of the palladium membrane inner component 59 corresponds to the structure of the decomposition interval 54, one end of the palladium membrane inner component 59 is a closed structure, and the other end of the palladium membrane inner component 59 is an open structure, and the end of the palladium membrane inner component 59 with the open structure is fixed on the lower surface of the separation interval 54 and is connected to the hydrogen outlet 521; multiple decomposition gas outlets 522 are connected to the first heat exchanger 3 at the same time, and the hydrogen outlet 521 is connected to the second heat exchanger 4. A vacuum pump 6 is arranged between the hydrogen outlet 521 and the second heat exchanger 4, and the vacuum pump is connected to the hydrogen outlet 521.

[0022] exist Figure 1 In the embodiment, the liquid ammonia tank 1 is directly connected to the vaporizer 2, and a first valve 11 is provided between the liquid ammonia tank 1 and the vaporizer 2. The first valve 11 is used to control the flow rate of liquid ammonia discharged from the liquid ammonia tank 1, so as to achieve effective control of the input liquid ammonia; the outlet of the vaporizer 2 is respectively connected to the first heat exchanger 3 and the second heat exchanger 4, and the outlet of the vaporizer 2 is provided with a three-way valve 12, and a part of the ammonia gas after vaporization is passed into the first heat exchanger 3 for heat exchange, and another part of the ammonia gas after vaporization is passed into the second heat exchanger 4 for heat exchange; specifically, the outlet of the vaporizer 2 is connected to one of the interfaces of the three-way valve 12, and the other two interfaces of the three-way valve 12 are respectively connected to the first heat exchanger 3 and the second heat exchanger 4, and the first heat exchanger 3 is connected to the ammonia inlet 51, and the first heat exchanger 3 is used to heat the ammonia gas therein, and the heated ammonia gas enters the palladium membrane internal component reactor 5 through the ammonia inlet 51.

[0023] like Figure 2-3As shown, the palladium membrane internal component reactor 5 includes an ammonia inlet 51, a hydrogen outlet 521, a plurality of decomposition gas outlets 522, and a connected decomposition interval 53 and a separation interval 54, the palladium membrane internal component reactor 5 is a vertical cylindrical structure, the decomposition interval 53 is located above the separation interval 54, the structures of the decomposition interval 53 and the separation interval 54 correspond, and the decomposition interval 53 and the separation interval 54 are both cylindrical structures, wherein an ammonia inlet 51 is provided directly above the decomposition interval 53 for introducing heated ammonia into the palladium membrane internal component reactor 5 for decomposition reaction; in order to prolong the flow time of ammonia, thereby improving the decomposition efficiency of ammonia and promoting the effective decomposition of ammonia, preferably, the A plurality of baffles 55 are arranged at intervals on the inner wall of the decomposition zone 53, and the plurality of baffles 55 are vertically fixed on the inner wall of the decomposition zone 53 and arranged around the inner wall of the decomposition zone 53; the plurality of baffles 55 can block the flow direction of ammonia, increase the turbulence of ammonia in the decomposition zone 53, and further increase the temperature distribution between the introduced ammonia, so that the temperature of the introduced ammonia is more uniform; the decomposition zone 53 is filled with an ammonia decomposition catalyst, and the ammonia decomposition catalyst is a ruthenium-based catalyst or a nickel-based catalyst; under the catalytic effect of the ammonia decomposition catalyst and the blocking effect of the plurality of baffles 53 on the flow of ammonia, ammonia is more fully decomposed into hydrogen and nitrogen in the decomposition zone 53; in order to prevent ammonia decomposition The decomposition catalyst blocks the gas flow, and at the same time, the internal gas pressure of the palladium membrane internal component reactor 5 is adjusted to promote the uniform and sufficient decomposition of ammonia. Specifically, a first filter screen 57 is fixed to one end of the decomposition interval 53 close to the separation interval 54. The first filter screen 57 is a mesh structure. A plurality of openings are provided on the first filter screen 57. The outer edge of the first filter screen 57 is connected to the inner wall of the decomposition interval 53. The first filter screen 57 separates the decomposition interval 53 and the separation interval 54. The first filter screen 57 can separate the ammonia decomposition catalyst from the decomposed gas. The ammonia decomposition catalyst is retained in the decomposition interval 53. The decomposed hydrogen and nitrogen are discharged through the openings on the first filter screen 57 and enter the separation area In order to further improve the decomposition effect of ammonia and the heat transfer effect, preferably, the first filter screen 57 is made of nickel metal. When the mixed gas flows through the first filter screen 57, under the catalytic action of nickel metal, the residual ammonia can continue to decompose and generate hydrogen and nitrogen for discharge, thereby reducing the content of residual ammonia in the mixed gas. More preferably, the decomposition interval 53 is provided with a first annular heating element 561 on the outside, and the cross-sectional shape of the first annular heating element 561 corresponds to the cross-sectional shape of the decomposition interval 53. The first annular heating element 561 can heat the decomposition interval 53, provide heat for the ammonia inside the decomposition interval 53, and improve the conversion efficiency of ammonia.

[0024] The separation interval 54 and the decomposition interval 53 are connected through the first filter screen 57. The palladium membrane inner component 59 is fixed inside the separation interval 54. Specifically, the palladium membrane inner component 59 is a hollow cylindrical structure. The installation direction of the palladium membrane inner component 59 coincides with the installation direction of the separation interval 54. The end of the palladium membrane inner component 59 disposed close to the decomposition interval 53 is a closed structure, and the end of the palladium membrane inner component 59 disposed toward the hydrogen outlet 521 is an open structure. The end of the palladium membrane inner component 59 with the open structure is fixed to the lower surface of the separation interval 54 and is directly connected to the hydrogen outlet 521. Preferably, The palladium membrane inner component 59 is located at the center of the separation interval 54; after the ammonia undergoes a preliminary decomposition reaction in the decomposition interval 53, the remaining hydrogen and nitrogen as well as the unreacted ammonia enter the separation interval 54, and the remaining ammonia continues to undergo a decomposition reaction in the decomposition interval 54; the generated hydrogen and nitrogen are respectively gathered on the two side surfaces of the palladium membrane inner component; according to the atomic radius of different gases, the palladium membrane inner component 59 selectively permeates the mixed gas: hydrogen penetrates into the palladium membrane inner component 59 through the palladium membrane inner component for collection, and is finally discharged through the hydrogen outlet 521; while nitrogen and unreacted ammonia are excluded from the palladium membrane inner component 5 9 outside, and finally discharged from the multiple decomposition gas outlets 522; to achieve effective separation and purification of hydrogen in the mixed gas, ensure the purity and concentration of hydrogen in the discharged gas, and reduce the content of nitrogen and ammonia in the discharged hydrogen; similarly, after the ammonia is initially separated in the decomposition zone 53, the obtained hydrogen-containing mixed gas is passed into the separation zone 54 containing the palladium membrane for separation. The initial concentration of hydrogen in the raw gas contacted by the palladium membrane is relatively high, and the hydrogen production efficiency per unit membrane area will be greatly improved; in addition, by continuously separating and purifying the hydrogen in the mixed gas, the product hydrogen is separated from the reaction system in situ, so that the chemical equilibrium can be carried out in the direction of generating product hydrogen, thereby improving the conversion efficiency of ammonia. , which is conducive to the forward decomposition reaction of ammonia; wherein the structure of the palladium membrane internal component 59 corresponds to the structure of the separation interval 54, and is located at the center of the separation interval 54, and the hydrogen outlet 521 and the multiple decomposition gas outlets 522 are both arranged near the bottom of the separation interval 54; specifically, the hydrogen outlet 521 is located at the center of the lower surface of the separation interval 54, and the multiple decomposition gas outlets 522 are arranged on the side wall of the separation interval 54, and the multiple decomposition gas outlets 522 are arranged opposite to each other, and the hydrogen outlet 521 is located at the center of the lower surface of the separation interval 54 and is directly connected to the inside of the palladium membrane internal component 59;The hydrogen outlet 521 is also connected to the vacuum pump 6. By directly connecting the hydrogen outlet 521 with the interior of the palladium membrane internal component 59 and the vacuum pump 6, the airflow inside the reactor, especially inside the separation interval 54, can be guided to quickly converge from the outer wall of the reactor to the center under the suction action of the vacuum pump 6. This flow control can guide the high-temperature heat of the outer wall to the center, which is convenient for the effective and concentrated distribution of heat, thereby achieving uniform heating of the ammonia and reducing the uneven heat absorption of ammonia. More preferably, in order to better promote the endothermic decomposition of ammonia and further reduce the residual ammonia in the mixed gas, the separation interval 54 is filled with an ammonia decomposition catalyst. A second filter screen 58 is sleeved on the outer wall of the second palladium membrane 592, and a plurality of through holes are opened on the second filter screen 58. The outer edge of the second filter screen 58 is connected to the inner wall of the separation zone 54. The second filter screen 58 is located above the hydrogen outlet 521 and the plurality of decomposition gas outlets 522. The second filter screen 58 is used to block and separate the ammonia decomposition catalyst, thereby separating the ammonia decomposition catalyst and the gas, preventing the ammonia decomposition catalyst from entering or blocking the decomposition gas outlet 522. The separated decomposition gas, including nitrogen and a small amount of unreacted ammonia, passes through the through holes on the second filter screen 58 and enters the plurality of decomposition gas outlets 522, and finally The decomposed gas is discharged through multiple decomposition gas outlets 522; the palladium membrane inner component 59 passes through the second filter screen 58 and is connected to the hydrogen outlet 521, so that the hydrogen can be discharged directly through the hydrogen outlet 521, and the separated nitrogen and a small amount of ammonia are discharged through multiple decomposition gas outlets 522, reducing the risk of secondary mixing of the decomposition gas and hydrogen, and effectively ensuring the purity of hydrogen preparation; more preferably, a second annular heating element 562 is provided on the outer wall of the separation interval 54, and the cross-sectional shape of the second annular heating element 562 corresponds to the cross-sectional shape of the separation interval 54, and the second annular heating element 562 is used to heat the separation interval 54. Heat is provided to more fully decompose ammonia. Under the catalytic action of the catalyst in the separation zone 54, the residual ammonia in the separation zone 54 is fully decomposed into hydrogen and nitrogen. The yield and purity of the hydrogen finally discharged are improved. More preferably, the palladium membrane internal component 59 is composed of a first palladium membrane 591 and a second palladium membrane 592, the second palladium membrane 592 is sheathed outside the first palladium membrane 591, the first palladium membrane 591 is a hollow cylindrical structure, the second palladium membrane 592 is a hollow cylindrical structure, and there is a gap between the first palladium membrane 591 and the second palladium membrane 592; the first palladium membrane 591 is directly connected to the hydrogen outlet 521. ;

[0025] The second filter screen 58 is made of nickel metal. By using nickel metal to prepare the second filter screen 58, the decomposition of ammonia can be promoted, and the heat can also be effectively transferred in the separation zone 54. By using a palladium membrane internal component 59 with a corresponding structure and arranged at the center of the decomposition zone 54, and the palladium membrane internal component 59 is directly connected to the hydrogen outlet 521, the gas and heat can be gathered toward the center of the decomposition zone 54, the air flow field and temperature field inside the catalyst bed can be controlled, and the decomposition effect of ammonia and the heating uniformity are improved. At the same time, the palladium membrane internal component 59 is directly connected to the hydrogen outlet 521. Compared with other separation materials, the membrane has the characteristics of high utilization rate and high selectivity for hydrogen, and can selectively permeate hydrogen efficiently, thereby increasing the amount and purity of hydrogen produced; by filling the ammonia decomposition catalyst in the palladium membrane internal component reactor 5 and separating them respectively using the first filter 57 and the second filter 58, the contact time between the reactants and the catalyst can be prolonged by reducing the flow rate, which is beneficial to the further occurrence of the reaction; in addition, the product hydrogen is separated from the reaction system in time, which reduces the probability of competitive adsorption with ammonia molecules, and is also beneficial to the adsorption and dissociation of ammonia at the catalytic active sites.

[0026] like Figure 1 As shown, the multiple decomposition gas outlets 522 of the palladium membrane internal component reactor 5 are connected to the first heat exchanger 3, and the separated nitrogen and unreacted ammonia discharged from the palladium membrane internal component reactor 5 are heat exchanged with the ammonia vaporized by the vaporizer 2 inside the first heat exchanger 3, so as to increase the temperature of the ammonia entering the palladium membrane internal component reactor 5 and accelerate the decomposition of the ammonia. The first heat exchanger 3 is used and the heat of the separated gas discharged is used to exchange heat with the ammonia, so as to achieve the reuse of heat and reduce the energy consumption of the system. In order to better improve the energy utilization rate of the system and reduce energy consumption, preferably, another fluid outlet of the first heat exchanger 3 is connected to the vaporizer 2, and the first exchange A burner 7 is arranged between another fluid outlet of the heat exchanger 3 and the vaporizer 2. The burner 7 can burn the gas after heat exchange in the first heat exchanger 3 to increase the heat of the gas after heat exchange. The burned gas is then introduced into the vaporizer 2 to provide heat for the vaporization of ammonia, thereby ensuring the stable operation and effective vaporization of the vaporizer 2 and improving the operation efficiency of the entire system; wherein, a second valve 13 is arranged between the first heat exchanger 3 and the burner 7, and a third valve 14 is arranged between the burner 7 and the vaporizer 2. By adjusting the corresponding valve opening, the vaporization process of the vaporizer 2 is controlled, and the temperature of the system and the ammonia decomposition efficiency are controlled.

[0027] Similarly, the second heat exchanger 4 is also connected to the ammonia inlet 51, and the second heat exchanger 4 is also connected to the vacuum pump 6. The vacuum pump 6 can introduce the high-purity hydrogen discharged after separation into the second heat exchanger 4. The second heat exchanger 4 can exchange heat between the separated hydrogen and the ammonia vaporized from the vaporizer 2 to reduce the temperature of the separated hydrogen, so as to better adapt to the use of hydrogen, such as the use of proton exchange membrane fuel cells; at the same time, it can also heat the vaporized ammonia to increase the temperature of the ammonia, which is beneficial to the subsequent endothermic decomposition of the ammonia. , reducing the heat required for ammonia decomposition, achieving effective reuse of system energy and reducing energy consumption; correspondingly, a fourth valve 15 is provided between the vacuum pump 6 and the second heat exchanger 4, a fifth valve 16 is provided between the second heat exchanger 4 and the ammonia inlet 51, and a sixth valve 17 is provided at the end of the second heat exchanger 4 for discharging hydrogen. By controlling the opening of the valves at the corresponding positions, the temperature control in the second heat exchanger 4 and the effective control and balance of the discharge amounts of hydrogen and ammonia can be achieved, thereby improving the flexibility of the system and further reducing the energy consumption of the system.

[0028] Compared with the traditional ammonia hydrogen production system that uses pressure swing adsorption to purify hydrogen, the ammonia decomposition hydrogen production system with palladium membrane internal components can avoid repeated purging steps; it has a high hydrogen recovery rate, low hydrogen loss during operation, and has the advantages of simple operation, higher adaptability, lower cost and higher recovery rate; by effectively combining ammonia decomposition and ammonia separation, the overall integration of the system is improved, the layout of system components is simplified, and it is more in line with the requirements of on-site hydrogen production by ammonia decomposition; using palladium membrane to separate and purify hydrogen can make the chemical equilibrium proceed in the direction of generating product hydrogen, and can also prolong the contact time between reactants and catalysts by reducing the flow rate. , which is conducive to the further occurrence of the reaction; and the temperature and gas can be concentrated during the reaction process, reducing the defects caused by uneven temperature distribution during the reaction process. On the basis of uniform temperature distribution, multiple heat exchangers are combined to achieve effective use of temperature, and at the same time, it is helpful to promote the decomposition reaction of ammonia, improve the energy utilization rate and hydrogen production and hydrogen purity of the overall system, and effectively realize the operation of proton exchange membrane fuel cells using liquid ammonia as raw material, overcoming the defects of existing pure hydrogen storage and transportation risks; the ammonia decomposition hydrogen production system containing palladium membrane internal components realizes the integration and miniaturization of the system, while saving additional equipment investment and reducing the operating cost of hydrogen production.

[0029] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. An ammonia decomposition hydrogen production system containing palladium membrane internals, comprising a liquid ammonia tank, a vaporizer, a first heat exchanger, a second heat exchanger and a palladium membrane internals reactor: characterized in that: The liquid ammonia tank is communicated with the vaporizer, and the vaporizer is also communicated with the first heat exchanger and the second heat exchanger at the same time; a part of the ammonia after vaporization is passed into the first heat exchanger, and another part of the ammonia after vaporization is passed into the second heat exchanger; the palladium membrane internal component reactor includes an ammonia inlet, a hydrogen outlet, a plurality of decomposition gas outlets, and a connected decomposition interval and separation interval, the decomposition interval is located above the separation interval, and the ammonia inlet is communicated with the decomposition interval; the hydrogen outlet and the plurality of decomposition gas outlets are all communicated with the separation interval; the hydrogen outlet is located above the separation interval, and the decomposition gas outlets are connected to the separation interval. on the lower surface of the separation interval; a palladium membrane inner component is fixed inside the separation interval, the structure of the palladium membrane inner component corresponds to the structure of the decomposition interval, one end of the palladium membrane inner component is a closed structure, and the other end of the palladium membrane inner component is an open structure, and the end of the palladium membrane inner component with the open structure is fixed on the lower surface of the separation interval and is connected with the hydrogen outlet; a plurality of decomposition gas outlets are simultaneously connected with the first heat exchanger, the hydrogen outlet is connected with the second heat exchanger, a vacuum pump is arranged between the hydrogen outlet and the second heat exchanger, and the vacuum pump is connected with the hydrogen outlet.

2. The ammonia decomposition hydrogen production system containing palladium membrane internal components according to claim 1, characterized in that: A first valve is provided between the liquid ammonia tank and the vaporizer, a three-way valve is provided at the outlet of the vaporizer, the outlet of the vaporizer is connected to one of the interfaces of the three-way valve, and the other two interfaces of the three-way valve are respectively connected to the first heat exchanger and the second heat exchanger.

3. The ammonia decomposition hydrogen production system containing palladium membrane internal components according to claim 1, characterized in that: The decomposition zone is located above the separation zone, a plurality of baffles are arranged at intervals on the inner wall of the decomposition zone, and the plurality of baffles are arranged around the inner wall of the decomposition zone. The interior of the decomposition zone is filled with an ammonia decomposition catalyst; the ammonia inlet is located directly above the decomposition zone.

4. The ammonia decomposition hydrogen production system containing palladium membrane internal components according to claim 1, characterized in that: A first filter screen is disposed at one end of the decomposition zone close to the separation zone, a plurality of openings are formed on the first filter screen, an outer edge of the first filter screen is connected to an inner wall of the decomposition zone, and the first filter screen is made of nickel metal.

5. The ammonia decomposition hydrogen production system containing palladium membrane internal components according to claim 1, characterized in that: The decomposition zone is provided with a first annular heating element on the outside, and the cross-sectional shape of the first annular heating element corresponds to the cross-sectional shape of the decomposition zone; the outer wall of the separation zone is provided with a second annular heating element, and the cross-sectional shape of the second annular heating element corresponds to the cross-sectional shape of the separation zone.

6. The ammonia decomposition hydrogen production system containing palladium membrane internal components according to claim 1, characterized in that: A second filter is sleeved on the outer wall of the palladium membrane inner component, and a plurality of through holes are opened on the second filter. The outer wall of the second filter is connected to the inner wall of the separation interval. The second filter is located above the hydrogen outlet and the plurality of decomposition gas outlets, and the second filter is made of nickel metal.

7. The ammonia decomposition hydrogen production system containing palladium membrane internals according to claim 6, characterized in that: The palladium membrane internal component passes through the second filter screen and is communicated with the hydrogen outlet, and the separation interval is filled with an ammonia decomposition catalyst.

8. The ammonia decomposition hydrogen production system containing palladium membrane internal components according to claim 1, characterized in that: One of the fluid outlets of the first heat exchanger is connected to the vaporizer, a burner is arranged between one of the fluid outlets of the first heat exchanger and the vaporizer, a second valve is arranged between the first heat exchanger and the burner, and a third valve is arranged between the burner and the vaporizer.

9. The ammonia decomposition hydrogen production system containing palladium membrane internal components according to claim 1, characterized in that: The second heat exchanger is connected to the ammonia inlet, a fourth valve is provided between the vacuum pump and the second heat exchanger, a fifth valve is provided between the second heat exchanger and the ammonia inlet, the second heat exchanger can exchange heat between the hydrogen introduced from the vacuum pump and the ammonia vaporized by the vaporizer, and a sixth valve is provided at one end of the second heat exchanger for discharging hydrogen.

10. An application of an ammonia decomposition hydrogen production system containing a palladium membrane internal component according to any one of claims 1 to 9, characterized in that: The ammonia decomposition hydrogen production system containing palladium membrane internal components is used for proton exchange membrane fuel cells.

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