Coaxial type DBD plasma device for hydrogen production from ammonia

Abstract

The application discloses a coaxial DBD plasma ammonia hydrogen production device cooperating with a proton exchange membrane, a device main body is provided with an ammonia decomposition reaction unit, an ammonia adsorption unit and a hydrogen separation unit, the ammonia reaction unit and the ammonia adsorption unit are both filled bed type coaxial DBD structures, the hydrogen separation unit is mainly a DBD structure formed by a ground electrode covered by a barrier medium and a proton exchange membrane, the ammonia decomposition reaction unit in the device main body is filled with a catalyst, and a spiral coil is arranged on the outer surface of the device, the device can improve the ammonia hydrogen production efficiency and effectively separate hydrogen by combining the filled bed type DBD plasma, ammonia decomposition and membrane separation treatment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plasma, and particularly relates to a coaxial DBD plasma and proton exchange membrane ammonia hydrogen production device. BACKGROUND

[0002] Global energy is in transition from fossil carbon hydrocarbon energy to renewable energy such as wind energy and solar energy. Hydrogen (H2) is considered an important fuel for future development as a renewable clean energy. The only product of its combustion is water, which can well replace carbon-containing energy and prevent the generation of CO X equal carbon oxides, avoiding the aggravation of environmental pollution. Certain small power generation devices, such as fuel cells, use hydrogen as fuel to produce green electricity. However, the delivery and storage of hydrogen hinder the development of hydrogen energy. Current research will generate H2 on site through ammonia (NH3), because NH3 can be condensed and liquefied at room temperature (25℃) and a relatively low pressure of about 10 atm, resulting in a higher volumetric energy density than pressurized H2. In addition, NH3 decomposition only produces nitrogen (N2) as a byproduct in principle, which does not increase the environmental burden. Therefore, ammonia can be used as a chemical storage medium for hydrogen storage and transportation, which can well solve the problem of hydrogen storage and transportation.

[0003] The traditional method of ammonia decomposition mainly includes thermal decomposition and catalyst decomposition. The thermodynamic equilibrium conversion rate of ammonia can reach 98% at 425℃, but in actual application, the thermal decomposition reaction is difficult to achieve in kinetics, and high temperature may cause problems such as reactor damage and flash explosion. On the other hand, ammonia decomposition for hydrogen production is usually coordinated with metal catalysts such as Ru, but although noble metal catalysts can effectively improve the efficiency of ammonia decomposition, they undoubtedly increase the cost of ammonia hydrogen production, and the effect of cheap metals is not ideal. In order to explore more efficient hydrogen production methods, scholars have continuously introduced new hydrogen production technologies.

[0004] In recent years, scientific research and engineering application fields have begun to pay more and more attention to the application of plasma in the field of ammonia decomposition for hydrogen production. The coupling of plasma technology and catalytic technology can not only combine the rapid efficiency of plasma, but also combine the high selectivity of catalysts, greatly improving the decomposition efficiency of ammonia. Dielectric barrier discharge (DBD) can generate large-area low-temperature plasma, i.e. non-equilibrium plasma, at normal pressure, which has the characteristics of high electron energy and low gas temperature. At present, non-equilibrium plasma has been applied to the treatment of organic pollutants, material surface treatment and other aspects. DBD mode has the advantages of good uniformity and stability, moderate energy density, simple structure, and is more promising in various industrial applications.

[0005] The membrane reactor composed of DBD dielectric barrier discharge and proton exchange membrane is a technology capable of effectively recovering hydrogen from ammonia, because it can simultaneously allow ammonia to decompose into hydrogen and nitrogen, and high-purity hydrogen separation. Compared with the traditional system of converting ammonia into pure hydrogen, this technology has advantages such as lower investment cost due to fewer process steps, and higher efficiency due to lower operating temperature. Since the decomposition of NH3 is limited by the thermodynamic equilibrium, the selective separation of hydrogen through the membrane wall actually turns the thermodynamic equilibrium to the reaction products (H2 and N2) according to the Le Chatelier principle, so that the membrane reactor bypasses the thermodynamic constraints of the conventional reactor. In particular, the palladium alloy membrane permeation separation technology is concerned in the field of hydrogen production from ammonia due to its advantages of high selectivity of hydrogen, strong hydrogen permeation performance, and good chemical and thermal stability.

[0006] Currently, the reaction device for hydrogen production from ammonia using DBD plasma has problems such as serious reverse reaction in the ammonia decomposition process, mixed gas as the generated product, and inability to simultaneously perform continuous decomposition and purification treatment on the gas. SUMMARY

[0007] Therefore, the present application provides a coaxial DBD plasma and proton exchange membrane hydrogen production device for ammonia, which can effectively treat ammonia and improve the phenomenon of "ammonia-hydrogen mixture", and can separate hydrogen in time and reduce reverse reaction.

[0008] In order to solve the above technical problems, the present application adopts the following technical scheme:

[0009] The coaxial DBD plasma and proton exchange membrane hydrogen production device for ammonia comprises a device main body, wherein the device main body is a horizontally placed closed coaxial DBD structure, the device main body is provided with a gas inlet and a gas outlet, the device main body is provided with an ammonia decomposition reaction unit, an ammonia adsorption unit and a hydrogen separation unit, glass wool is placed on both sides of the ammonia decomposition reaction unit and the ammonia adsorption unit and in the middle of the ammonia decomposition reaction unit and the ammonia adsorption unit, the ammonia decomposition reaction unit is a packed bed type DBD dielectric barrier discharge area composed of a ground electrode covered with a barrier medium and a proton exchange membrane covered with a barrier medium; the ammonia adsorption unit is a packed bed type DBD dielectric barrier discharge area composed of a ground electrode covered with a barrier medium and a proton exchange membrane covered with a barrier medium; the hydrogen separation unit is a DBD dielectric barrier discharge area composed of a ground electrode covered with a barrier medium and a proton exchange membrane, and the outer surface of the device main body is provided with a spiral coil.

[0010] Further, the gas inlet is located on the left side of the ammonia decomposition reaction unit, away from the packed bed type DBD dielectric barrier discharge region, the gas inlet diameter is 2.0mm-5.0mm, the gas inlet is provided with a mass flow meter, the gas inlet and the ammonia decomposition reaction unit are in sealed connection, and the gas outlet is located at the center of the proton exchange membrane, and the gas outlet and the hydrogen separation unit are in sealed connection.

[0011] Further, the length of the device body is 50cm, the length of the blocking medium covering the proton exchange membrane is 0.5cm-35cm, and the thickness is 1mm.

[0012] Further, characterized in that the outer layer of the device body is a grounding electrode, the length of the blocking medium covering the grounding electrode is 10cm-50cm, and the thickness is 1mm.

[0013] Further, characterized in that the distance between the outer spiral coil of the device body and the surface of the device body is 1mm, and the number of turns of the spiral coil is 100 turns.

[0014] Further, characterized in that the length of the proton exchange membrane is 10cm-50cm, and the thickness is 1mm.

[0015] Further, the length of the buffer area from the gas inlet of the device body to the packed bed is 0.5cm-10cm; the length of the ammonia decomposition reaction unit is 0.5cm-15cm; the length of the ammonia adsorption unit is 0.5cm-10cm; and the length of the hydrogen separation unit is 0.5cm-15cm.

[0016] Further, the distance between the proton exchange membrane and the grounding electrode of the ammonia decomposition reaction unit is 5mm-10mm, the distance between the proton exchange membrane and the grounding electrode of the ammonia adsorption unit is 5mm-10mm, and the distance between the proton exchange membrane and the grounding electrode of the hydrogen separation unit is 6mm-11mm.

[0017] Further, the proton exchange membrane is a palladium-copper alloy membrane, and the grounding electrode is made of copper, aluminum alloy, stainless steel, or gold / copper plating.

[0018] Further, the material of the blocking medium is quartz glass, ceramic, polytetrafluoroethylene, or tempered glass.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The device for ammonia hydrogen production by coaxial DBD plasma and proton exchange membrane of the application combines plasma treatment and hydrogen separation treatment, realizes ammonia decomposition for hydrogen production and timely separation of hydrogen by reasonably matching discharge plasma, greatly improves the conversion rate of ammonia, improves the stability and timeliness of ammonia decomposition, and improves the phenomena of "ammonia decomposition reverse reaction" and "ammonia and hydrogen mixture", which has important significance and practical value for realizing more efficient and economical industrial application of ammonia decomposition for hydrogen production. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings described herein are used to provide further understanding of the application, constitute a part of the application, and the illustrative embodiments of the application and the description thereof are used to explain the application and do not constitute improper limitations on the application. In the drawings:

[0022] Figure 1 is an internal structure diagram of the device for ammonia hydrogen production by coaxial DBD plasma and proton exchange membrane of the application;

[0023] Figure 2 is an external structure diagram of the device for ammonia hydrogen production by coaxial DBD plasma and proton exchange membrane of the application;

[0024] Figure 3 is an overall schematic diagram of the device for ammonia hydrogen production by coaxial DBD plasma and proton exchange membrane of the application;

[0025] Figure 4 is an internal cross-sectional schematic diagram of the device for ammonia hydrogen production by coaxial DBD plasma and proton exchange membrane of the application;

[0026] Figure 5 is a schematic diagram of the ammonia decomposition reaction unit structure in the device for ammonia hydrogen production by coaxial DBD plasma and proton exchange membrane of the application;

[0027] Figure 6 is a schematic diagram of the ammonia adsorption unit structure in the device for ammonia hydrogen production by coaxial DBD plasma and proton exchange membrane of the application.

[0028] In the drawings, 1 is an air inlet, 2 is a grounding electrode, 3 is a proton exchange membrane, 4 is glass wool, 5 is a spiral coil, 6 is a bracket, 7 is a barrier medium, 8 is an air outlet, 9 is a catalyst Ni / MgO, and 10 is a zeolite molecular sieve. DETAILED DESCRIPTION

[0029] The embodiments of the application will be described in detail below with examples, so that how the application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented.

[0030] The application discloses a coaxial DBD plasma and proton exchange membrane ammonia hydrogen production device. Figure 1 As shown in the figure, the device body is horizontally placed and is a closed coaxial DBD structure, the device body is provided with a gas inlet 1 and a gas outlet 8, and the device body is provided with an ammonia decomposition reaction unit, an ammonia adsorption unit and a hydrogen separation unit, glass wool 4 is placed on both sides of the ammonia decomposition reaction unit and the ammonia adsorption unit and in the middle of the ammonia decomposition reaction unit and the ammonia adsorption unit, the ammonia decomposition reaction unit is a packed bed type DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3 covering the barrier medium 7, the ammonia adsorption unit is a packed bed type DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3 covering the barrier medium 7, and the hydrogen separation unit is a DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3, and the ammonia decomposition reaction unit, the ammonia adsorption unit and the hydrogen separation unit share the grounding electrode 2 and the proton exchange membrane 3. Figure 2 As shown in the figure, the device body is horizontally placed and is a closed coaxial DBD structure, the device body is provided with a gas inlet 1 and a gas outlet 8, and the device body is provided with an ammonia decomposition reaction unit, an ammonia adsorption unit and a hydrogen separation unit, glass wool 4 is placed on both sides of the ammonia decomposition reaction unit and the ammonia adsorption unit and in the middle of the ammonia decomposition reaction unit and the ammonia adsorption unit, the ammonia decomposition reaction unit is a packed bed type DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3 covering the barrier medium 7, the ammonia adsorption unit is a packed bed type DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3 covering the barrier medium 7, and the hydrogen separation unit is a DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3, and the ammonia decomposition reaction unit, the ammonia adsorption unit and the hydrogen separation unit share the grounding electrode 2 and the proton exchange membrane 3.

[0031] As shown in the figure, the device body is horizontally placed and is a closed coaxial DBD structure, the device body is provided with a gas inlet 1 and a gas outlet 8, and the device body is provided with an ammonia decomposition reaction unit, an ammonia adsorption unit and a hydrogen separation unit, glass wool 4 is placed on both sides of the ammonia decomposition reaction unit and the ammonia adsorption unit and in the middle of the ammonia decomposition reaction unit and the ammonia adsorption unit, the ammonia decomposition reaction unit is a packed bed type DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3 covering the barrier medium 7, the ammonia adsorption unit is a packed bed type DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3 covering the barrier medium 7, and the hydrogen separation unit is a DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3, and the ammonia decomposition reaction unit, the ammonia adsorption unit and the hydrogen separation unit share the grounding electrode 2 and the proton exchange membrane 3. Figure 3 As shown in the figure, the device body is horizontally placed and is a closed coaxial DBD structure, the device body is provided with a gas inlet 1 and a gas outlet 8, and the device body is provided with an ammonia decomposition reaction unit, an ammonia adsorption unit and a hydrogen separation unit, glass wool 4 is placed on both sides of the ammonia decomposition reaction unit and the ammonia adsorption unit and in the middle of the ammonia decomposition reaction unit and the ammonia adsorption unit, the ammonia decomposition reaction unit is a packed bed type DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3 covering the barrier medium 7, the ammonia adsorption unit is a packed bed type DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3 covering the barrier medium 7, and the hydrogen separation unit is a DBD dielectric barrier discharge area formed by a grounding electrode 2 covering a barrier medium 7 and a proton exchange membrane 3, and the ammonia decomposition reaction unit, the ammonia adsorption unit and the hydrogen separation unit share the grounding electrode 2 and the proton exchange membrane 3.

[0032] The length of the device body is 10cm-50cm adjustable, the length of the barrier medium 7 covering the proton exchange membrane 3 is 0.5cm-35cm adjustable, and the thickness is 1mm. The outer layer of the device body is a grounding electrode, the length of the barrier medium 7 covering the grounding electrode 2 is 10cm-50cm adjustable, and the thickness is 1mm. The distance between the spiral coil 5 surrounding the outer part of the device body and the surface of the device body is 1mm, and the number of turns of the spiral coil 5 is 100 turns. The length of the proton exchange membrane 3 is 10cm-50cm adjustable, and the thickness is 1mm. The length of the buffer area from the gas inlet 1 to the packed bed is 0.5cm-10cm adjustable; the length of the ammonia decomposition reaction unit is 0.5cm-15cm adjustable; the length of the ammonia adsorption unit is 0.5cm-10cm adjustable; and the length of the hydrogen separation unit is 15cm adjustable.

[0033] like Figure 4 The figure shows a cross-sectional view of the main body of the device. The distance between the proton exchange membrane 3 and the grounding electrode 2 in the ammonia decomposition reaction unit is adjustable from 5mm to 10mm. The distance between the proton exchange membrane 3 and the grounding electrode 2 in the ammonia adsorption unit is adjustable from 5mm to 10mm. The distance between the proton exchange membrane 3 and the grounding electrode 2 in the hydrogen separation unit is adjustable from 6mm to 11mm.

[0034] The proton exchange membrane 3 can be a metallic proton membrane such as a palladium-copper alloy membrane; the material of the blocking medium 7 can be, but is not limited to, quartz glass, ceramic, polytetrafluoroethylene, tempered glass, etc.; the grounding metal mesh as the grounding electrode 2 can be, but is not limited to, copper, aluminum alloy, stainless steel, gold / copper plating, etc.

[0035] The specific working process of the device of the present invention is as follows:

[0036] like Figure 5 As shown, the ammonia decomposition reaction unit is a coaxial packed bed DBD dielectric barrier discharge structure. The reaction gap of the ammonia decomposition reaction unit is filled with Ni / MgO9 catalyst. The reaction gas flows in through glass wool 4 and flows out to the ammonia adsorption unit.

[0037] like Figure 6 As shown, the ammonia adsorption unit is a coaxial packed bed DBD dielectric barrier discharge structure. Zeolite molecular sieve 10 is filled in the reaction gap of the gas adsorption unit, which can promote micro-discharge to further process the mixed gas and adsorb excess ammonia. Then, hydrogen enters the hydrogen separation unit.

[0038] like Figure 4 As shown, the hydrogen separation unit is a coaxial DBD dielectric barrier discharge structure. The proton exchange membrane 3 has no barrier medium 7. The hydrogen in the reaction gas is decomposed into H ions in the reaction gap and separated out through the proton exchange membrane. The hydrogen flows out from the outlet 8.

[0039] This invention utilizes direct purification combined with DBD plasma to achieve hydrogen production from ammonia. The Ar / NH3 mixed gas is first processed by an ammonia decomposition reaction unit. The charged ions, highly active groups, and photoelectric effects in the plasma, along with the catalyst Ni / MgO, cause ammonia molecules to collide with high-energy metastable argon atoms, generating Penning excitation and ionization reactions. This breaks the NH bonds, effectively generating electron collision reactions to excite and produce NH4+. *The generated mixed gas flows into the ammonia gas adsorption unit through glass wool; in the ammonia gas adsorption unit, the zeolite molecular sieve has a microporous structure, which can promote the generation of micro-discharge to realize the further decomposition of ammonia gas, and the zeolite molecular sieve is an acidic material, which can adsorb excess ammonia gas to avoid the damage of ammonia gas to metal materials; in the hydrogen gas separation unit, hydrogen gas is decomposed into H free radicals under the action of plasma, and high-concentration H free radicals penetrate into the gas outlet by the proton exchange membrane, so that the purification of hydrogen gas is finally realized.

[0040] The ammonia gas decomposition reaction unit, the ammonia gas adsorption unit and the hydrogen gas separation unit are arranged in a complete closed system, and the three are continuous in the mechanism and the process, and belong to independent working links without direct interaction; the spiral coil outside the device main body plays an auxiliary role in the system work, and the charged particles do Larmor cyclotron motion under the action of the vertical magnetic field, so that the residence time of the gas particles is increased, and the probability of ion collision is also increased.

[0041] The above description shows and describes several preferred embodiments of the application, but as described above, it should be understood that the application is not limited to the forms disclosed herein, should not be regarded as excluding other embodiments, and can be used in various other combinations, modifications and environments, and can be modified within the scope of the inventive concept described herein by the above teaching or related art or knowledge. The modifications and changes made by those skilled in the art without departing from the spirit and scope of the application shall be within the protection scope of the claims of the application.

Claims

1. A coaxial DBD plasma-assisted proton exchange membrane ammonia-to-hydrogen apparatus, characterized in that, The device includes a main body, which is a horizontally placed, closed, coaxial DBD structure. The main body has an air inlet and an air outlet. Inside the main body are an ammonia decomposition reaction unit, an ammonia adsorption unit, and a hydrogen separation unit. Glass wool is placed on both sides and between the ammonia decomposition reaction unit and the ammonia adsorption unit. The ammonia decomposition reaction unit is a filled-bed DBD dielectric barrier discharge region consisting of a grounding electrode covered with a barrier medium and a proton exchange membrane covered with a barrier medium. The ammonia adsorption unit is a filled-bed DBD dielectric barrier discharge region consisting of a grounding electrode covered with a barrier medium and a proton exchange membrane covered with a barrier medium. The hydrogen separation unit is a DBD dielectric barrier discharge region consisting of a grounding electrode covered with a barrier medium and a proton exchange membrane covered with a barrier medium. A spiral coil is provided on the outer surface of the main body.

2. The apparatus for coaxial DBD plasma-assisted proton exchange membrane ammonia hydrogen production according to claim 1, characterized in that, The air inlet is located on the left side of the ammonia decomposition reaction unit, away from the packed bed DBD dielectric barrier discharge area. The diameter of the air inlet is 2.0mm-5.0mm. A mass flow meter is installed at the air inlet. The air inlet and the ammonia decomposition reaction unit form a sealed connection. The air outlet is located at the center of the proton exchange membrane. The air outlet and the hydrogen separation unit form a sealed connection.

3. The apparatus for coaxial DBD plasma-assisted proton exchange membrane ammonia hydrogen production according to claim 1, characterized in that, The main body of the device is 50cm long, and the barrier medium covering the proton exchange membrane is 0.5cm-35cm long and 1mm thick.

4. The apparatus for coaxial DBD plasma-assisted proton exchange membrane ammonia hydrogen production according to claim 3, characterized in that, The outer layer of the main body of the device is a grounding electrode, and the blocking medium covering the grounding electrode has a length of 10cm-50cm and a thickness of 1mm.

5. The apparatus for coaxial DBD plasma-assisted proton exchange membrane ammonia hydrogen production according to claim 1, characterized in that, The distance between the spiral coil surrounding the main body of the device and the surface of the main body is 1mm, and the spiral coil has 100 turns.

6. The apparatus for coaxial DBD plasma-assisted proton exchange membrane ammonia hydrogen production according to claim 1, characterized in that, The proton exchange membrane has a length of 10cm-50cm and a thickness of 1mm.

7. The apparatus for coaxial DBD plasma-assisted proton exchange membrane ammonia hydrogen production according to claim 1, characterized in that, The length of the buffer zone from the main air inlet of the device to the packed bed is 0.5cm-10cm; the length of the ammonia decomposition reaction unit is 0.5cm-15cm; the length of the ammonia adsorption unit is 0.5cm-10cm; and the length of the hydrogen separation unit is 0.5cm-15cm.

8. The apparatus for coaxial DBD plasma-assisted proton exchange membrane ammonia hydrogen production according to claim 1, characterized in that, The distance between the proton exchange membrane and the grounding electrode in the ammonia decomposition reaction unit is 5mm-10mm, the distance between the proton exchange membrane and the grounding electrode in the ammonia adsorption unit is 5mm-10mm, and the distance between the proton exchange membrane and the grounding electrode in the hydrogen separation unit is 6mm-11mm.

9. The apparatus for coaxial DBD plasma-assisted proton exchange membrane ammonia hydrogen production according to claim 1, characterized in that, The proton exchange membrane is a palladium-copper alloy membrane, and the grounding electrode is made of copper, aluminum alloy, stainless steel, or gold / copper plating.

10. The apparatus for coaxial DBD plasma-assisted proton exchange membrane ammonia hydrogen production according to claim 1, characterized in that, The material used for the blocking medium is quartz glass, ceramic, polytetrafluoroethylene, or tempered glass.

Images