Plasma reforming hydrogen production apparatus and method

Abstract

The application discloses a kind of plasma reforming hydrogen production device and method, belong to hydrogen production technical field.The plasma reforming hydrogen production device includes reaction cavity shell, at least one plasma torch and at least one atomizing nozzle are equipped on the reaction cavity shell, the plasma torch is used to generate plasma jet;The atomizing nozzle is used to generate hydrogen-containing raw material jet;The outlet of the plasma torch and the outlet of atomizing nozzle are located on the surface or inside reaction cavity shell, and form included angle, so that plasma jet and hydrogen-containing raw material jet meet in reaction cavity shell, form reaction zone.The application separates reaction zone and discharge area, avoids hydrogen-containing droplet into discharge area, so that discharge area remains as pure gas phase environment, and then enhances the stability of discharge, improves the efficiency of hydrogen production.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen production technology, and more specifically, relates to a plasma reforming hydrogen production apparatus and method. Background Technology

[0002] Hydrogen, as a high-calorific-value and clean secondary energy source, has made its efficient and low-carbon production technology a current research hotspot. Traditional methanol-to-hydrogen technologies, such as steam reforming, require high temperatures (>200°C) and the action of catalysts, resulting in drawbacks such as high energy consumption, easy catalyst deactivation, and complex systems.

[0003] Plasma technology can initiate chemical reactions at room temperature and pressure, providing a new pathway for low-temperature hydrogen production. Plasma is a high-temperature or high-energy conductive gas formed by the ionization of a gas under a strong electric field. Plasma hydrogen production utilizes high-energy plasma to crack or reform hydrogen-containing feedstocks (such as water, methane, methanol, and biomass) to efficiently generate hydrogen. Its core advantages lie in the fact that it requires no catalyst, has a fast reaction rate, and can handle a variety of feedstocks. Compared to gaseous hydrogen-containing feedstocks, liquid hydrogen-containing feedstocks (such as methanol, ethanol, and methylcyclohexane) have significant advantages in terms of volumetric energy density and long-distance transportation.

[0004] Atomizing liquid hydrogen-containing feedstocks and reacting them with high-energy plasma can significantly increase the reaction contact area and energy transfer efficiency, thereby accelerating the reaction rate and increasing hydrogen yield, which is superior to directly using liquid or gaseous feedstocks. Patent CN104591085A discloses a micro-plasma reforming method for methanol to hydrogen production. In this method, methanol solution is atomized to form a methanol spray, which enters a micro-plasma device through an inlet. A high voltage is applied to ionize the methanol spray between electrodes, resulting in a plasma chemical reforming reaction that generates hydrogen-rich syngas. In this prior art, the discharge occurs in the spray region between the electrodes, which is a gas-liquid two-phase mixture. The presence of liquid components significantly interferes with discharge stability. Furthermore, the high dielectric constant of methanol droplets leads to uneven electric field distribution and localized fluctuations in electric field strength, making it difficult to maintain a stable discharge mode. This results in a small reaction area and unstable discharge, thus affecting the efficiency of hydrogen production. Summary of the Invention

[0005] 1. The problem to be solved To address the problem of liquid hydrogen-containing feedstock entering the discharge zone and affecting the stability of plasma discharge in existing plasma reforming hydrogen production technologies, this invention provides a plasma reforming hydrogen production device that separates the hydrogen production reaction zone from the discharge zone, thereby improving the stability of discharge and the efficiency of hydrogen production.

[0006] 2. Technical Solution To solve the above problems, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a plasma reforming hydrogen production apparatus, comprising a reaction chamber shell, wherein at least one plasma spray gun and at least one atomizing nozzle are provided on the reaction chamber shell, the plasma spray gun is used to generate a plasma jet; the atomizing nozzle is used to generate a hydrogen-containing feed jet; the outlet of the plasma spray gun and the outlet of the atomizing nozzle are located on the surface or inside of the reaction chamber shell and form an angle, such that the plasma jet and the hydrogen-containing feed jet converge within the reaction chamber shell to form a reaction zone.

[0007] Preferably, the distance between the intersection of the plasma jet gun axis and the atomizing nozzle axis and the plasma jet gun outlet is no more than 20 mm, so that the hydroxyl radicals in the plasma jet still have sufficient activity when they reach the intersection to initiate the reforming hydrogen production reaction.

[0008] More preferably, the outlet of the plasma spray gun and the outlet of the atomizing nozzle are on the same horizontal plane; the included angle between the axis of the plasma spray gun and the axis of the atomizing nozzle is 30°~60°.

[0009] More preferably, the distance between the outlet of the plasma spray gun and the outlet of the atomizing nozzle is no more than 37 mm, so that the hydroxyl radicals in the plasma jet remain active when the hydrogen-containing droplets reach the reaction zone.

[0010] More preferably, the distance between the outlet of the plasma spray gun and the outlet of the atomizing nozzle is no more than 15 mm.

[0011] More preferably, the distance between the intersection of the plasma spray gun axis and the atomizing nozzle axis and the plasma spray gun outlet is 10~20mm, so that when the hydrogen-containing droplets come into contact with the plasma jet and react, the hydroxyl radicals have sufficient activity, and the hydrogen-containing droplets are confined within the plasma jet.

[0012] Preferably, the diameter of the plasma jet outlet is 1-5 mm, so that the high-speed plasma jet emitted by the plasma jet forms a shear layer between the plasma jet and the surrounding fluid, thereby generating turbulent vortexes that actively draw surrounding hydrogen-containing droplets into the plasma jet.

[0013] Preferably, the plasma spray gun includes a spray gun housing, a central electrode is provided inside the spray gun housing, a nozzle electrode is provided above the central electrode, a gap is left between the central electrode and the nozzle electrode, and a gas channel is provided on the spray gun housing, which is connected to the gap between the central electrode and the nozzle electrode to introduce working gas into the gap to form a discharge zone.

[0014] More preferably, the nozzle electrode has an outlet for the plasma spray gun, and the plasma jet formed in the discharge region is ejected from the outlet of the plasma spray gun.

[0015] More preferably, the spray gun housing and the central electrode are separated by an insulating medium.

[0016] A second aspect of the present invention provides a plasma reforming method for hydrogen production, employing the plasma reforming hydrogen production apparatus described in any embodiment of the first aspect of the present invention, the steps of which include: S1. The liquid hydrogen-containing raw material is atomized into hydrogen-containing droplets using an atomizing nozzle, and the hydrogen-containing raw material jet is ejected from the outlet of the atomizing nozzle; S2. Start the plasma spray gun. A stable discharge is generated inside the plasma spray gun, and the plasma jet is ejected from the outlet of the plasma spray gun. S3. The hydrogen-containing raw material jet reacts with the plasma jet inside the reaction chamber shell; S4. Separate and collect the products after the reaction.

[0017] Preferably, in step S1, the Sotter average diameter of the hydrogen-containing droplet is 10~100μm, more preferably, the Sotter average diameter is 20~50μm; and the average velocity of the hydrogen-containing droplet is 15~30m / s.

[0018] Preferably, in step S2, the average velocity of the plasma jet is 20~30m / s.

[0019] Preferably, the liquid hydrogen-containing feedstock includes one or more of methanol, ethanol, ethylene glycol, glycerol, dimethyl ether, and bio-oil.

[0020] 3. Beneficial effects Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In the plasma reforming hydrogen production device provided by the present invention, the discharge zone of the plasma jet is located inside the plasma nozzle, and the reaction zone between the plasma jet and the hydrogen-containing raw material jet is located outside the plasma nozzle. By separating the discharge zone and the reaction zone, the liquid hydrogen-containing raw material is prevented from entering the discharge zone, so that the discharge zone is kept in a pure gas phase environment, thereby enhancing the stability of the discharge and improving the efficiency of hydrogen production. (2) The plasma reforming hydrogen production device provided by the present invention sets the distance between the intersection of the plasma spray gun axis and the atomizing nozzle axis and the plasma spray gun outlet to no more than 20 mm, so that the plasma jet containing hydroxyl radicals emitted by the plasma spray gun reaches the reaction zone within its lifespan, ensuring the activity of hydroxyl radicals when the plasma jet reacts with the hydrogen-containing raw material, and further improving the efficiency of hydrogen production. (3) The plasma reforming hydrogen production device provided by the present invention sets the distance between the outlet of the plasma spray gun and the outlet of the atomizing nozzle, which are on the same horizontal plane and have an angle of 30° to 60°, to no more than 37 mm, so that the hydroxyl radicals in the plasma jet are still active when the hydrogen-containing droplets reach the reaction zone. (4) The plasma reforming hydrogen production device provided by the present invention further sets the distance between the intersection of the plasma spray gun axis and the atomizing nozzle axis and the plasma spray gun outlet to 10~20mm, so that the hydrogen-containing droplets are bound after entering the plasma jet; the hydrogen-containing droplets and the plasma jet react more fully, which can improve the hydrogen production efficiency. (5) The plasma reforming hydrogen production device provided by the present invention sets the diameter of the plasma nozzle outlet to 1~5mm, so that the high-speed plasma jet emitted by the plasma nozzle forms a shear layer between the plasma jet and the surrounding fluid, thereby generating turbulent vortexes, actively drawing the surrounding hydrogen-containing droplets into the plasma jet, increasing the proportion of hydrogen-containing droplets participating in the reaction, and further improving the efficiency of hydrogen production. (6) The plasma reforming hydrogen production device provided by the present invention does not utilize the energy of the afterglow region, but directly uses the high-energy jet of plasma, which has the advantages of high energy utilization, fast reaction rate and high concentration of active species. (7) The plasma reforming hydrogen production method provided by the present invention improves the stability of plasma discharge by isolating the reforming hydrogen production reaction zone and the plasma discharge zone, and solves the problem of low conductivity hydrogen-containing droplets (such as methanol liquid with a conductivity of about 10) - 5 The S / m ratio leads to problems such as a small reaction zone, distorted electric field distribution, and deflection or alteration of the discharge path. This avoids the frequent start-up and shutdown of the plasma gun caused by the inability of the discharge channel to maintain a stable geometric path, thereby improving the efficiency of hydrogen production. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a plasma reforming hydrogen production apparatus provided in an embodiment of the present invention; Figure 2 A cross-sectional view of a plasma reforming hydrogen production apparatus provided in an embodiment of the present invention; Figure 3 A schematic diagram of the structure of the plasma spray gun in the plasma reforming hydrogen production device provided in an embodiment of the present invention; Figure 4 A perspective view of the plasma spray gun in the plasma reforming hydrogen production apparatus provided in an embodiment of the present invention; In the diagram: 1. Reaction chamber shell; 2. Plasma spray gun; 21. Spray gun shell; 22. Central electrode; 23. Insulating medium; 24. Nozzle electrode; 25. Gas channel; 3. Atomizing nozzle; 4. Discharge port. Detailed Implementation

[0022] It should be noted that when a component is referred to as being "mounted" on another component, it can be directly on the other component or the two components can be integrated as one unit; when a component is referred to as being "connected" to another component, it can be directly connected to the other component or the two components can be integrated as one unit. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0024] As used herein, “adjacent” means that two structures or elements are close to each other. Specifically, elements identified as “adjacent” may be adjacent or connected. Such elements may also be close to or near each other without necessarily touching. In some cases, the precision of proximity may depend on the specific context.

[0025] The present invention will be further described below with reference to specific embodiments.

[0026] Example 1 like Figure 1~2 As shown, this embodiment provides a plasma reforming hydrogen production device, including a reaction chamber shell 1 and a plasma spray gun 2 and an atomizing nozzle 3 located on the reaction chamber shell 1. The plasma spray gun 2 is used to generate a plasma jet, and a discharge zone is formed inside the plasma spray gun 2. The atomizing nozzle 3 is used to generate a hydrogen-containing raw material jet. The outlet of the plasma spray gun 2 and the outlet of the atomizing nozzle 3 are located on the surface or inside the reaction chamber shell 1 and form an angle, so that the plasma jet and the hydrogen-containing raw material jet converge inside the reaction chamber shell 1 to form a reaction zone.

[0027] like Figure 3~4 As shown, the plasma spray gun 2 includes a spray gun housing 21, within which a central electrode 22 is disposed. The spray gun housing 21 and the central electrode 22 are separated by an insulating medium 23. A nozzle electrode 24 is disposed above the central electrode 22, with a gap between the central electrode 22 and the nozzle electrode 24. An outlet for the plasma spray gun 2 is formed in the nozzle electrode 24. A gas channel 25 is provided on the spray gun housing 21, communicating with the gap between the central electrode 22 and the nozzle electrode 24, for introducing working gas into the gap to form a discharge region. In one embodiment, the nozzle electrode 24 is fixedly connected to the spray gun housing 21.

[0028] In one embodiment, the nozzle electrode 24 has a ring-shaped structure with an outlet for the plasma spray gun 2 at its center, and the plasma jet formed in the discharge region is ejected from the outlet of the plasma spray gun 2.

[0029] The spray gun housing 21, the central electrode 22, and the nozzle electrode 24 are coaxial. The intersection of the axis of the nozzle electrode 24 and the axis of the atomizing nozzle 3 is located inside the reaction chamber housing 1, so that the plasma jet and the hydrogen-containing raw material jet converge inside the reaction chamber housing 1 to form a reaction zone.

[0030] In this embodiment, after the plasma spray gun 2 is activated, the working gas between the central electrode 22 and the nozzle electrode 24 is ionized by a high-frequency electric field, and this region is the discharge region. The discharge region generates a low-temperature plasma jet containing a large number of hydroxyl radicals (·OH). These hydroxyl radicals have extremely strong oxidizing power, which promotes the rapid activation and cracking of hydrogen-containing raw material molecules, thereby accelerating hydrogen generation and inhibiting the accumulation of by-products.

[0031] In actual experiments, factors such as the activity of hydroxyl radicals when the plasma jet and the hydrogen-containing raw material jet meet, whether the hydrogen-containing raw material and the plasma jet can react fully, and whether the hydrogen-containing raw material can be entrained by the plasma jet all affect the hydrogen production efficiency. Therefore, the following calculations are used to study the distance between the intersection of the axis of plasma spray gun 2 and the axis of atomizing nozzle 3 and the outlet of plasma spray gun 2, the distance between the outlet of plasma spray gun 2 and the outlet of atomizing nozzle 3, and the diameter of the outlet of plasma spray gun 2.

[0032] (1) The distance between the intersection of the axis of plasma spray gun 2 and the axis of atomizing nozzle 3 and the outlet of plasma spray gun 2 shall not exceed 20mm: As one implementation method, in order to improve the efficiency of hydrogen production, the hydroxyl radical jet emitted by the plasma spray gun 2 should reach the reaction zone within its lifetime. Therefore, it is necessary to control the distance between the intersection of the axis of the plasma spray gun 2 and the axis of the atomizing nozzle 3 and the outlet of the plasma spray gun 2. L That is, the distance between the reaction zone and the discharge zone. The plasma jet 2 ejects a circular plasma jet from its outlet, allowing the plasma jet to reach... L Time elapsed t travel Chemical lifetime less than or equal to that of hydroxyl radicals t OH ， This distance satisfies the formula:

[0033] In the formula, x This represents the distance of the plasma jet from the outlet of plasma gun 2. u axis (x () represents the velocity of the plasma jet along the axis of plasma nozzle 2. L The distance from the outlet of plasma spray gun 2 is the intersection of the axis of plasma spray gun 2 and the axis of atomizing nozzle 3.

[0034] In this invention u axis (x) The classical velocity distribution model conforms to that of a circular free jet:

[0035] In the formula, u 0 represents the average velocity of the plasma jet at the exit of plasma gun 2. D The diameter of the plasma spray gun 2 outlet. x c This is the distance from the plasma jet nozzle 2 outlet to the boundary between the plasma jet core region and the attenuation region. When 0 ≤x≤x c At this time, the plasma jet is located in the core region, which is a potential core region near the exit where the velocity does not decrease significantly. In this region, the plasma jet's velocity along its axis remains almost constant. x > x c When the plasma jet enters the decay region, the high-energy particles in the decay region continuously entrain the low-temperature, low-speed ambient gas, and their axial velocity will continue to decrease along the way.

[0036] It should be noted that in this invention t OH The values ​​were obtained from a literature search (Wu Shuqun, Dong Xi, Pei Xuekai, et al. Spatiotemporal distribution of OH radicals and O atoms in atmospheric pressure low-temperature plasma jets based on laser-induced fluorescence method [J]. Journal of Electrical Engineering, 2017, No. 8: 82-94).

[0037] In this embodiment, based on experiments and calculations, t OH It takes 1ms. u 0 is 20 m / s (commonly used) u 0 is 20~30m / s). D It is 2mm. x c For a 5D, i.e., 10mm, the calculation is performed by substituting the above values ​​into formulas (1) and (2), and we can obtain the following results. L ≤18.7mm.

[0038] because t travel same u 0 is inversely proportional to the same L Proportional, thereforeu When 0 > 20 m / s, L The value can be greater than 18.7 mm. Considering the uncertainties such as plasma jet pulsation and gas composition fluctuations in actual operation, the distance between the intersection of the plasma spray gun 2 axis and the atomizing nozzle 3 axis and the plasma spray gun 2 outlet is... L The design is set to be no greater than 20mm, meaning the distance between the reaction zone and the discharge zone is no more than 20mm, which ensures... u 0. Within the commonly used range, hydroxyl radicals still possess sufficient activity to initiate reforming hydrogen production reactions when they reach the junction.

[0039] (2) The distance between the outlet of the plasma spray gun 2 and the outlet of the atomizing nozzle 3 shall not exceed 15 mm: To ensure that the reaction zone is located inside the reaction chamber shell 1 and separated from the discharge zone, the outlet of the plasma spray gun 2, which provides the plasma jet, and the outlet of the atomizing nozzle 3, which provides hydrogen-containing droplets, cannot be located at the same place. At the same time, to ensure that the plasma jet and the hydrogen-containing droplets converge inside the reaction chamber shell 1, the axis of the plasma spray gun 2 and the axis of the atomizing nozzle 3 need to form a certain angle, which is usually 30~60°, so that the high-energy plasma jet can better contact the hydrogen-containing droplets. However, when the axis of the atomizing nozzle 3 forms an angle with the direction of gravity, the hydrogen-containing droplets in the hydrogen-containing raw material jet have a downward velocity component when flying towards the plasma jet. This means that if the distance between the outlet of the plasma gun 2 and the outlet of the atomizing nozzle 3 is too large, the hydrogen-containing raw material jet will be too far from the outlet of the plasma gun 2 when it meets the plasma jet, and the hydroxyl radicals will lose their activity before the reaction. By controlling the distance between the outlet of the plasma gun 2 and the outlet of the atomizing nozzle 3, it can be further ensured that the hydroxyl radicals are still active when the hydrogen-containing raw material jet meets the plasma jet.

[0040] When a hydrogen-containing droplet reaches the boundary of a plasma jet (the outer edge of the plasma jet profile), the following conditions must be met:

[0041]

[0042] in, Δr The distance between the outlet of plasma spray gun 2 and the outlet of atomizing nozzle 3. v p,r The radial velocity of the hydrogen-containing droplet perpendicular to the plasma jet axis is denoted as . t The time it takes for the hydrogen-containing droplet to travel from ejection to the boundary of the plasma jet. r boundary The distance of the plasma jet from the exit of plasma gun 2 is... z The radius that expands linearly along the radial direction.v p The average velocity of the hydrogen-containing feed jet ejected from atomizing nozzle 3. r boundary = 2.5 βz , β Let be the jet expansion constant, in the direction parallel to the plasma jet axis. z=v p,z t , v p,z The axial velocity of the hydrogen-containing droplet parallel to the plasma jet axis is given. i The angle between the axis of the plasma spray gun 2 and the axis of the atomizing nozzle 3.

[0043] In this embodiment, it is assumed that the angle θ between the axis of the plasma spray gun 2 and the axis of the atomizing nozzle 3 is 30°, the outlet of the plasma spray gun 2 and the outlet of the atomizing nozzle 3 are on the same horizontal plane, and the radial velocity of the hydrogen-containing droplets perpendicular to the plasma jet axis is... v p,r =v p sin30° = 0.5 v p The axial velocity of the hydrogen-containing droplet parallel to the plasma jet axis is v p,z =v p cos30 =0.866 v p , β Take 0.1, in the direction parallel to the plasma jet axis, z=v p,z t , and v p,r = 0.5 v p , v p,z = 0.866 v p Substituting into formula (3), we can obtain Δr =0.827 z .

[0044] According to the calculation based on formula (1), in order to ensure that the hydroxyl radical still has sufficient activity to initiate the reforming hydrogen production reaction when it reaches the junction, z It should not exceed 18.7mm, therefore Δr ≤15.46mm. Similarly, it can be deduced that when the angle θ between the axis of plasma spray gun 2 and the axis of atomizing nozzle 3 is 60°, Δr ≤37.06mm.

[0045] Therefore, when the angle θ between the axis of the plasma spray gun 2 and the axis of the atomizing nozzle 3 is 30°~60°, the outlet of the plasma spray gun 2 and the outlet of the atomizing nozzle 3 are on the same horizontal plane and the distance between them is no more than 37mm. This allows the hydroxyl radicals to remain active when the hydrogen-containing raw material jet meets the plasma jet.

[0046] Furthermore, the outlet of the plasma spray gun 2 and the outlet of the atomizing nozzle 3 are on the same horizontal plane and the distance between them is no more than 15mm. At this time, the angle θ between the axis of the plasma spray gun 2 and the axis of the atomizing nozzle 3 can be set to any value between 30° and 60°.

[0047] (3) Furthermore, when the outlet of the plasma spray gun 2 and the outlet of the atomizing nozzle 3 are on the same horizontal plane, the distance between the intersection of the axis of the plasma spray gun 2 and the axis of the atomizing nozzle 3 and the outlet of the plasma spray gun 2 is... z The distance between the intersection of the axis of plasma spray gun 2 and the axis of atomizing nozzle 3 and the outlet of plasma spray gun 2 should be no less than 11.12 mm, i.e., 10~20 mm. Furthermore, the lateral penetration depth of the hydrogen-containing droplets after entering the plasma jet needs to be no greater than the cross-sectional diameter of the plasma jet perpendicular to the axis of the plasma spray gun 2, so that the hydrogen-containing droplets are confined within the plasma jet and the reaction time is increased.

[0048] Assuming the hydrogen-containing droplet has an initial velocity v p The lateral penetration depth of the plasma jet region y pen It can be determined by the following formula:

[0049] in, D The diameter of the plasma spray gun 2 outlet. r p The density of the hydrogen-containing droplets, r The density of the working gas, d p The diameter of the hydrogen-containing droplet. v p,r The radial velocity of the hydrogen-containing droplet perpendicular to the plasma jet axis is denoted as . u 0 represents the average velocity of the plasma jet at the exit of plasma gun 2.

[0050] In this embodiment, methanol is used as a liquid hydrogen-containing raw material. D Take 2mm, r pGiven that the density of methanol is 792 kg / m³, r The density of argon gas at room temperature (20℃) and normal pressure (1 atm) is 1.78 kg / m³. d p Take 35μm, v p,r Take 15 m / s, u 0 is taken as 20 m / s. Substituting the above values ​​into formula (5), we get y pen =5.56mm.

[0051] After a hydrogen-containing droplet enters a plasma jet, if its lateral penetration depth... y pen If it is not greater than the cross-sectional diameter of the plasma jet, then y pen ≤2 r boundary That is, 5.56mm ≤ 2 × 2.5 × 0.1 × z , and thus z ≥11.12mm, which is the distance between the intersection of the axis of plasma spray gun 2 and the axis of atomizing nozzle 3 and the outlet of plasma spray gun 2. z When the droplet size is not less than 11.12 mm, the hydrogen-containing droplet will be confined within the plasma jet.

[0052] (4) Furthermore, when the following conditions are met: the outlet of plasma spray gun 2 and the outlet of atomizing nozzle 3 are on the same horizontal plane and the distance between them is no greater than 37 mm; and the distance between the intersection of the axis of plasma spray gun 2 and the axis of atomizing nozzle 3 and the outlet of plasma spray gun 2 is between 11.12 and 18.7 mm, when hydrogen-containing droplets react with the plasma jet, the hydroxyl radicals have sufficient activity, and the hydrogen-containing droplets are confined within the plasma jet, allowing the reaction to proceed fully and significantly improving the efficiency of hydrogen production. In actual experiments, considering uncertainties such as the pulsation of the plasma jet and fluctuations in gas composition, the distance between the intersection of the axis of plasma spray gun 2 and the axis of atomizing nozzle 3 and the outlet of plasma spray gun 2 can be 10 to 20 mm.

[0053] (5) The diameter of the outlet of plasma spray gun 2 is 1~5mm: As one implementation method, in order to achieve the formation of a shear layer between the high-speed plasma jet emitted by the plasma gun 2 and the surrounding fluid, thereby generating turbulent vortices and actively "entraining" and mixing the surrounding atomized hydrogen-containing droplets into the plasma jet body to improve hydrogen production efficiency, the diameter of the plasma gun 2 outlet (referring to the cross-sectional diameter of the plasma gun 2 outlet perpendicular to the axis of the plasma gun 2) needs to meet the following requirements:

[0054] in, Re The Reynolds number is... r The density of the working gas, u 0 represents the average velocity of the plasma jet at the exit of plasma gun 2. D The diameter of the plasma spray gun 2 outlet. m The dynamic viscosity of the working gas in plasma spray gun 2.

[0055] In this embodiment, the working gas is argon, and its density and dynamic viscosity at room temperature (20°C) and normal pressure (1 atm) are used. r It is 1.78 kg / m³. m 2.1×10 -5 Pa·s. When u When 0 is 20 m / s, D ≥2.36mm, when u When 0 is 30 m / s, D ≥1.57mm. Depending on the actual conditions, the diameter of the plasma spray gun 2 outlet shall not be less than 1mm and not more than 5mm.

[0056] To facilitate monitoring of the discharge and reaction status, the reaction chamber shell 1 can be made of a transparent material. In one embodiment, the reaction chamber shell 1 can be provided with multiple outlets 4. The outlet 4 at the bottom is used to discharge residual liquid, while the outlets 4 on the side walls or top are used to discharge gaseous products. The outlet 4 at the bottom can be equipped with a gas-liquid separation structure, which can be a conical bottom or a baffle separator. Unreacted hydrogen-containing droplets are collected and discharged through this outlet 4 or returned to the reaction chamber via a circulation pipeline. The outlets 4 on the side walls or top are connected to a condenser, cooled by circulating cooling water or refrigerant, to condense hydrogen vapor and water vapor in the product gas, with the operating temperature controlled between -10 and 5°C. After the condenser, a hydrogen purification unit is connected, using pressure swing adsorption to purify the hydrogen.

[0057] To optimize the electric field distribution and promote stable discharge, the end of the center electrode 22 closest to the nozzle electrode 24 is tapered. The center electrode 22 is made of a high-melting-point, ablation-resistant material, including tungsten, molybdenum, tantalum, or their alloys, to ensure no ablation or impurity precipitation during discharge. To accommodate the discharge gap, the diameter of the center electrode 22 is preferably 2-6 mm, and the gap between the center electrode 22 and the nozzle electrode 24 is preferably 1-5 mm.

[0058] The nozzle electrode 24 is made of copper or a copper alloy, which has both high electrical and thermal conductivity, allowing for rapid dissipation of discharge heat and preventing localized overheating. Preferably, the nozzle electrode 24 is a one-piece molded electrode.

[0059] The insulating medium 23 is made of alumina ceramic or silicon nitride ceramic to achieve electrical isolation between the center electrode 22 and the nozzle electrode 24, preventing short circuits, and can withstand the high temperatures generated by discharge. To ensure a uniform electric field distribution in the discharge gap, the thickness of the insulating medium 23 should be uniform.

[0060] To enhance corrosion resistance, the spray gun housing 21 is made of a material selected from stainless steel, nickel-based alloys, titanium, titanium alloys, copper, or copper alloys. The plasma spray gun 2 is equipped with cooling channels, such as water-cooled or air-cooled structures, to maintain the thermal stability of the spray gun during long-term operation. The plasma spray gun 2 is equipped with a gas channel 25, and the working gas used includes argon, helium, nitrogen, or mixtures thereof, with a gas purity ≥99.99%. The gas flow rate can be precisely controlled at 4~8 L / min via a mass flow controller to ensure the jet is in a fully developed turbulent state.

[0061] In one embodiment, the atomizing nozzle 3 is a pressure atomizing nozzle, which has the advantages of simple structure, small and controllable atomized particle size, wide flow range, flexible adjustment, and low cost. In other embodiments, the atomizing nozzle 3 can also be an ultrasonic atomizing nozzle or a rotary atomizing nozzle.

[0062] The Sauter mean diameter (SMD) of the hydrogen-containing droplets ejected from the atomizing nozzle 3 is controlled within the range of 10–100 μm, preferably 20–50 μm. If the SMD is large, the specific surface area is small, leading to incomplete reaction; conversely, the mass of the hydrogen-containing droplets is small, making it difficult to have sufficient momentum to penetrate the jet region. The following behavior of the hydrogen-containing droplets to the airflow is characterized by the Stokes number. For example, a methanol droplet with a diameter of 20 μm in an argon jet has a Stokes number less than 0.2, and much less than 1. Under these conditions, the dominant mechanism for methanol droplet transport is the interaction between the methanol droplet and the turbulence, rather than inertia. That is, the methanol droplet almost completely follows the airflow and cannot overcome the radial pressure gradient of the plasma jet boundary layer, thus failing to contact the high concentration of hydroxyl radicals. The reaction only occurs at the interface between the methanol droplet surface and the plasma jet boundary, resulting in a small reaction area and low conversion rate.

[0063] The atomizing cone angle of the atomizing nozzle 3 is preferably 30°~60° to ensure effective intersection with the plasma jet. Here, the "atomizing cone angle" is defined as the radial angle of the hydrogen-containing feed jet. The liquid hydrogen-containing feed used in the atomizing nozzle 3 includes one or more of methanol, ethanol, ethylene glycol, glycerol, dimethyl ether, and bio-oil.

[0064] To prevent corrosion, the atomizing nozzle 3 can be made of either stainless steel or ceramic. The internal flow channels of the atomizing nozzle 3 are smooth and free of dead corners, preventing clogging. The front end of the atomizing nozzle 3 can be designed as a detachable structure for easy cleaning and replacement.

[0065] In this embodiment, one plasma spray gun 2 and four atomizing nozzles 3 are all located at the top of the reaction chamber housing 1. In other embodiments, the number of plasma spray guns 2 can be more than one, and the number of atomizing nozzles 3 is not limited to four. Furthermore, the plasma spray gun 2 and atomizing nozzles 3 can be located on different sides of the reaction chamber housing 1. For example, the plasma spray gun 2 and atomizing nozzles 3 can be arranged opposite each other, respectively installed on both sides of the reaction chamber housing 1, with the jet direction opposite to the atomization direction, forming a highly turbulent mixing zone in the central region of the reaction chamber. This mode can enhance the momentum exchange and mixing effect between the gas and liquid phases.

[0066] Example 2 This embodiment provides a plasma reforming method for hydrogen production, the steps of which include: S1. Liquid methanol is delivered to the atomizing nozzle 3 by a peristaltic pump, and the raw material is atomized into hydrogen-containing droplets with an average diameter of 10~100μm, preferably 20~50μm. The methanol jet is ejected from the outlet of the atomizing nozzle 3 with an average velocity of 15~30m / s. S2. Argon gas with a flow rate of 4~6L / min is introduced into the plasma spray gun 2, and the voltage is gradually increased to 5~30kV. Stable discharge is generated in the gap between the central electrode 22 and the nozzle electrode 24 inside the plasma spray gun 2, which ionizes the argon gas to form a uniform and continuous atmospheric pressure plasma jet. The plasma jet is ejected from the outlet of the plasma spray gun 2 at high speed with an average velocity of 20~30m / s. S3. The plasma jet reacts with the hydrogen-containing droplets in the reaction chamber shell 1, triggering the dissociation and reforming reaction of the hydrogen-containing droplets; S4. The gaseous products generated by the reaction (mainly H2 and CO, and a small amount of CO2, CH4, etc.) accumulate at the top of the reaction chamber shell 1 and are discharged through the top outlet 4. The unreacted hydrogen-containing droplets settle to the bottom of the reaction chamber shell 1 and are discharged through the bottom outlet 4.

[0067] In the plasma reforming hydrogen production apparatus provided by this invention, a high voltage is applied between the central electrode 22 and the nozzle electrode 24 in the plasma spray gun 2, causing the working gas to be ionized and forming a plasma state, which is then ejected at high speed from the nozzle electrode 24 to form a plasma jet. Since the plasma jet is generated in a pure gas phase environment inside the plasma spray gun, it reacts with atomized hydrogen-containing droplets in the reaction chamber shell 1 only after being ejected from the nozzle electrode 24. The reaction zone is far from the discharge zone of the plasma spray gun, preventing liquid from entering the discharge gap and interfering with the discharge stability, thereby improving the efficiency of hydrogen production.

[0068] The above description provides an illustrative overview of the present invention and its embodiments. This description is not restrictive, and the embodiments shown are merely one example of the invention's implementation. Actual implementations are not limited to these examples. Therefore, if those skilled in the art are inspired by this description and design similar implementations and examples without departing from the spirit of the invention, such designs should fall within the scope of protection of the present invention.

Claims

1. A plasma reforming hydrogen production apparatus, comprising a reaction chamber shell (1), characterized in that: The reaction chamber housing (1) is provided with at least one plasma spray gun (2) and at least one atomizing nozzle (3). The plasma spray gun (2) is used to generate a plasma jet; The atomizing nozzle (3) is used to generate a hydrogen-containing raw material jet; The outlet of the plasma spray gun (2) and the outlet of the atomizing nozzle (3) are located on the surface or inside the reaction chamber shell (1) and form an angle, so that the plasma jet and the hydrogen-containing raw material jet converge in the reaction chamber shell (1) to form a reaction zone.

2. The plasma reforming hydrogen production apparatus according to claim 1, characterized in that: The distance between the intersection of the axis of the plasma spray gun (2) and the axis of the atomizing nozzle (3) and the outlet of the plasma spray gun (2) is no more than 20 mm.

3. The plasma reforming hydrogen production apparatus according to claim 2, characterized in that: The outlet of the plasma spray gun (2) and the outlet of the atomizing nozzle (3) are on the same horizontal plane; The angle between the axis of the plasma spray gun (2) and the axis of the atomizing nozzle (3) is 30°~60°.

4. The plasma reforming hydrogen production apparatus according to claim 3, characterized in that: The distance between the outlet of the plasma spray gun (2) and the outlet of the atomizing nozzle (3) is no greater than 37 mm.

5. The plasma reforming hydrogen production apparatus according to claim 4, characterized in that: The distance between the outlet of the plasma spray gun (2) and the outlet of the atomizing nozzle (3) is no greater than 15 mm.

6. The plasma reforming hydrogen production apparatus according to any one of claims 3 to 5, characterized in that: The distance between the intersection of the axis of the plasma spray gun (2) and the axis of the atomizing nozzle (3) and the outlet of the plasma spray gun (2) is 10~20mm.

7. The plasma reforming hydrogen production apparatus according to any one of claims 1 to 5, characterized in that: The diameter of the outlet of the plasma spray gun (2) is 1~5mm.

8. The plasma reforming hydrogen production apparatus according to any one of claims 1 to 5, characterized in that: The plasma spray gun (2) includes a spray gun housing (21), a central electrode (22) is provided inside the spray gun housing (21), and a nozzle electrode (24) is provided above the central electrode (22). A gap is left between the central electrode (22) and the nozzle electrode (24). A gas channel (25) is provided on the spray gun housing (21), and the gas channel (25) is connected to the gap between the central electrode (22) and the nozzle electrode (24) for introducing working gas into the gap to form a discharge area; and / or, An outlet for the plasma jet (2) is opened in the nozzle electrode (24), and the plasma jet formed in the discharge region is ejected from the outlet of the plasma jet (2).

9. A method for producing hydrogen through plasma reforming, characterized in that: The plasma reforming hydrogen production apparatus according to any one of claims 1 to 8 comprises the following steps: S1. The liquid hydrogen-containing raw material is atomized into hydrogen-containing droplets using the atomizing nozzle (3), and the hydrogen-containing raw material jet is ejected from the outlet of the atomizing nozzle (3); S2. Start the plasma spray gun. A stable discharge is generated inside the plasma spray gun (2), and the plasma jet is ejected from the outlet of the plasma spray gun (2). S3, The hydrogen-containing raw material jet reacts with the plasma jet inside the reaction chamber shell (1); S4. Separate and collect the products after the reaction.

10. The plasma reforming method for hydrogen production according to claim 9, characterized in that: In step S1, the average velocity of the hydrogen-containing droplet jet is 15~30 m / s; and / or, The Sotter average diameter of the hydrogen-containing droplets is 10~100 μm; and / or, In step S2, the average velocity of the plasma jet is 20~30m / s.

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