System and method for hydrogen production by means of decomposition using array plasma

Abstract

A system and method for hydrogen production by means of decomposition using array plasma. The system comprises a reactor group, a high-voltage power supply (3), a waste-liquid recovery device (8), a raw-material reservoir group, a filter (13), a membrane separator (14), a waste-gas recovery device (15) and a hydrogen collector (16), wherein reactors (1, 2) are each internally provided with an array electrode and a ring electrode (20), and the array electrode comprises a plurality of high-voltage electrodes (17) arranged in an array; each high-voltage electrode (17) comprises an insulating sleeve (27) and a metal pin electrode (28); the insulating sleeve (27) is sleeved outside the metal pin electrode (28); and the upper end of the insulating sleeve (27) is provided with a porous medium (29) having catalytic properties. The array electrodes are arranged in the reactors (1, 2), and the porous mediums (29) having catalytic properties are coupled to the tips of the array electrodes, thereby achieving a synergistic enhancement effect of catalysts and plasma, and improving hydrogen selectivity and the energy utilization efficiency of the plasma; and a liquid phase discharges by means of a strong electric field to generate plasma, thereby prompting a liquid fuel to rapidly decompose so as to produce hydrogen.

Description

Array plasma decomposition hydrogen production system and method TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen production, and particularly relates to an array plasma decomposition liquid fuel hydrogen production system and method. BACKGROUND

[0002] Developing hydrogen energy is an important way to realize green and low-carbon transformation of energy structure under the global "double carbon" background. In the process of hydrogen energy industry development, preparation and storage and transportation are the most important. According to the production source and carbon emission in the production process, hydrogen can be divided into gray hydrogen, blue hydrogen and green hydrogen. In the future, the proportion of green hydrogen is expected to continue to increase and gradually replace gray hydrogen. The hydrogen production mode based on renewable resources is an important prerequisite for the development of the hydrogen energy industry in the future, such as electrolysis of water, methanol / ethanol reforming, ammonia decomposition and other hydrogen production modes with solar photovoltaic or wind power as the power supply condition. In addition, the process of hydrogen from "factory" to "tank" also faces many challenges. Traditional high-pressure hydrogen storage and low-temperature liquid hydrogen storage belong to physical hydrogen storage mode, and there are still controversies in the safety and economy of hydrogen storage tanks and transportation equipment.

[0003] Liquid fuels such as methanol, ethanol, liquid ammonia and the like are important hydrogen-rich raw materials, which can be obtained by various ways such as biomass and renewable energy, and have many advantages such as low cost, easy storage and transportation, low energy consumption, environmental friendliness and the like, which have strategic significance for guaranteeing energy security, promoting energy substitution and realizing sustainable development. According to the latest global hydrogen production source data statistics of the International Energy Agency, the proportion of hydrogen production from alcohol raw materials is second only to natural gas, reaching 30%. In the world, there is a perfect transportation and distribution system, and its complete infrastructure is what hydrogen energy application lacks and needs.

[0004] The traditional liquid fuel hydrogen production method mainly includes four types of steam reforming, cracking reforming, partial oxidation and oxidative steam reforming. Steam reforming for hydrogen production usually requires a high conversion temperature. The cracking reforming method has high requirements for the reactor, and the high-temperature reaction often needs to rely on high-efficiency catalysts to strengthen the reaction. The partial oxidation method does not need additional heating, but has a serious problem of catalyst sintering. The oxidative steam reforming method is a commonly used hydrogen production method, but it needs high temperature, high pressure and catalyst, and has high energy consumption and needs a large amount of steam. Although the conventional liquid fuel hydrogen production process has been commercially applied, the overall efficiency and economic index are low, and improvement is needed in terms of conversion efficiency, cost and sustainability. Therefore, it is necessary to explore liquid fuel hydrogen production technology with fast reaction speed, simple equipment and low energy consumption, and to develop environmentally friendly liquid fuel hydrogen production process with good industrial application prospect. SUMMARY

[0005] In view of the above technical problems, one of the purposes of one of the embodiments of the present application is to provide an array plasma decomposition hydrogen production system and method, which sets an array needle electrode in a reactor and couples a porous medium with catalytic properties at the tip of the array needle electrode, realizes a synergistic reinforcement effect of the catalyst and the plasma, and improves hydrogen selectivity and plasma energy utilization efficiency. By applying a high-voltage alternating current or pulse power to generate Joule heat at the tip of the electrode, the liquid fuel is locally vaporized to generate bubbles, and then the discharge is initiated inside the bubbles to generate plasma with rich high-energy active substances, which promotes the rapid decomposition reaction of the liquid fuel to produce hydrogen, and the small bubbles are separated from the discharge area in the form of small bubbles. The process requires less injection energy, low energy consumption, and thus reduces the operating cost of the system. It is a new online green hydrogen production technology with high efficiency and low cost.

[0006] Note that the description of these objects does not hinder the existence of other objects. One of the embodiments of the present application does not need to realize all the above-mentioned purposes. The purposes other than the above-mentioned purposes can be extracted from the description, drawings, and claims.

[0007] The present application realizes the above technical purposes through the following technical means.

[0008] An array plasma decomposition hydrogen production system, comprising a reactor group, a high-voltage power supply, a waste liquid recovery device, a raw material storage group, a filter, a membrane separator, a waste gas recovery device, and a hydrogen collector;

[0009] The reactor group comprises at least one reactor, the exhaust port of the reactor is connected to the inlet of the filter and the membrane separator in sequence through pipelines, the outlet of the membrane separator is connected to the waste gas recovery device and the hydrogen collector respectively, the liquid inlet of the reactor is connected to the raw material storage group through a pipeline, and an electric shut-off valve is arranged on the pipeline between the liquid inlet and the raw material storage group; the raw material storage group is used to provide liquid fuel for the reactor group;

[0010] The reactor is provided with an array electrode and a ring electrode, the array electrode is arranged at the bottom of the reactor, and the ring electrode is located above the array electrode; the ring electrode is grounded, and the array electrode is connected to the high-voltage power supply.

[0011] In the above scheme, the array electrode comprises a plurality of high-voltage electrodes arranged in an array;

[0012] The high-voltage electrode comprises an insulating sleeve and a metal needle electrode; the insulating sleeve is sleeved on the metal needle electrode; and the upper end of the insulating sleeve is tightly embedded with a porous medium with catalytic properties.

[0013] Further, the porous medium is made of nickel-based and copper-based catalysts.

[0014] In the scheme, the insulating sleeve array is arranged on an insulating sleeve fixing plate, the insulating sleeve fixing plate is arranged at the bottom of the reactor and is arranged in sealing with the wall surface around the reactor; the metal needle electrode array is arranged on a high-voltage electrode fixing plate, and the insulating sleeve fixing plate is arranged above the high-voltage electrode fixing plate.

[0015] In the scheme, the material of the metal needle electrode tip is platinum, and the material of the needle body is copper or tungsten; the diameter of the metal needle electrode body is 2 mm to 4 mm, and the curvature of the needle tip is 10° to 30°.

[0016] In the scheme, the reactor group includes a first reactor and a second reactor.

[0017] The exhaust port of the first reactor is connected to the inlet of the filter and the membrane separator in sequence through a pipeline, the outlet of the membrane separator is connected to the waste gas collector and the hydrogen collector respectively, the liquid inlet of the first reactor is connected to the first raw material reservoir through a pipeline, and a first electric shut-off valve is arranged on the pipeline between the liquid inlet and the first raw material reservoir.

[0018] The second reactor has the same structure as the first reactor; the exhaust port of the second reactor is connected to the inlet of the filter and the membrane separator in sequence through a pipeline, the outlet of the membrane separator is connected to the waste gas collector and the hydrogen collector respectively, the liquid inlet of the second reactor is connected to the second raw material reservoir through a pipeline, and a second electric shut-off valve is arranged on the pipeline between the liquid inlet and the second raw material reservoir.

[0019] A first circuit breaker is arranged on the line connecting the array electrode of the first reactor to the high-voltage power supply; a second circuit breaker is arranged on the line connecting the array electrode of the second reactor to the high-voltage power supply.

[0020] Further, it further includes a waste liquid treatment system; the waste liquid treatment system includes a waste liquid collector, a three-way valve and a water pump; two inlets of the three-way valve are connected to the waste liquid outlet communication pipelines of the first reactor and the second reactor respectively, the outlet of the three-way valve is connected to the communication pipeline of the waste liquid collector; a water pump is arranged on the pipeline connecting the outlet of the three-way valve to the inlet of the waste liquid collector.

[0021] In the scheme, a circulating cooling temperature control system is further included; the circulating cooling temperature control system includes a cooling box, a cooling water inlet and a cooling water outlet; the reactor of the reactor group is composed of two sleeves, and the space between the two sleeves is connected to the cooling water inlet and the cooling water outlet respectively.

[0022] A method according to the array plasma decomposition hydrogen production system, comprising the following steps:

[0023] The raw material reservoir group provides liquid fuel for the reactor group, after the liquid fuel enters the reactor through the liquid inlet to a certain liquid level, the circulating cooling temperature control system is started to control the temperature, the input voltage adjustable high voltage power supply is turned on, and the oscilloscope equipped with voltage and current probes is used to record the electric signal; the upper end of the high voltage electrode and the ring electrode are always immersed in the reaction liquid during the hydrogen production reaction, the upper end of the insulating sleeve is tightly embedded with porous media with catalytic properties, under the synergistic effect of plasma and catalyst, the liquid fuel is efficiently decomposed to produce hydrogen mixture and dispersed in the liquid phase in the form of small bubbles, the exhaust port is connected, the hydrogen mixture passes through the filter to filter out the water in the gas and the reaction liquid vapor, the mixed gas is purified through the membrane separator, and the obtained high-purity hydrogen enters the hydrogen reservoir, and the remaining mixed gas enters the waste gas collector.

[0024] In the above scheme, a reactor alternating use step is further included:

[0025] When the first reactor and the second reactor need to be switched, the first reactor is stopped by cutting off the first circuit breaker, and the second reactor is started by closing the second circuit breaker.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] 1. High efficiency and rapidity: According to one mode of the present application, by regularly arranging array electrodes at the bottom of the reactor, the decomposition of liquid fuel by plasma can be greatly intensified under low energy consumption injection conditions, the reaction rate and hydrogen production efficiency are improved, and the hydrogen production cost is greatly reduced.

[0028] 2. Green and environmentally friendly: Liquid fuels represented by methanol are cheap, easy to obtain, environmentally friendly, and can be obtained through renewable energy sources such as biomass, are easy to store and transport, have low energy consumption for hydrogen production, and are expected to break the long-term dependence on fossil energy. According to one mode of the present application, the plasma decomposition of liquid fuel for hydrogen production technology almost does not produce greenhouse gases such as carbon dioxide, and can be considered as a "zero carbon" process, so it is suitable for clean energy conversion. This technology can drive hydrogen fuel cells, reduce air pollution, promote the application of clean energy in the transportation field, and help achieve the goal of low-carbon energy and emission reduction.

[0029] 3. Catalytic synergy: According to one mode of the present application, porous media with catalytic properties are fixed at the tip of the needle electrode, realizing the synergistic effect of catalyst and plasma. The small bubbles produced greatly increase the interfacial area, increase the number of discharges per unit time, and improve the selectivity of hydrogen and the energy utilization efficiency of plasma.

[0030] 4. Adjustable and replaceable: according to one mode of the present application, a fitting device is arranged at the bottom of the reactor, and the number of electrodes can be adjusted according to the demand for hydrogen production, and the damaged electrodes can be replaced at any time; in addition, the design of the standby reactor can be switched in time when the main reactor is replaced with electrodes and the waste liquid is removed to ensure that hydrogen production is carried out continuously and efficiently.

[0031] 5. Cooling and temperature control: according to one mode of the present application, a circulating cooling system is arranged between the two layers of sleeves, which not only solves the problem of the upward movement of liquid fuel in the reactor caused by joule heat in time, but also controls the temperature in the reactor, and provides the best reaction temperature for hydrogen production reaction when necessary.

[0032] 6. Waste utilization: according to one mode of the present application, the waste liquid collector arranged between the main reactor and the standby reactor in series can effectively recover the waste liquid produced by long-time reaction, which not only avoids environmental pollution but also can be post-treated for secondary use; in addition, the main components of the gas after the hydrogen gas is purified by the membrane separator are carbon monoxide and a small amount of alkane, and carbon monoxide is one of the important chemical raw materials and has a wide application in industrial production, so to some extent, the present application can simultaneously and efficiently produce green hydrogen and carbon monoxide.

[0033] Note that the description of these effects does not hinder the existence of other effects. One mode of the present application does not necessarily have all the above effects. Effects other than the above can be clearly seen and extracted from the description, drawings, claims, etc.

[0034] BRIEF DESCRIPTION OF DRAWINGS

[0035] The present application is further illustrated by the following drawings, but the drawings in the following description are examples of the existing embodiments, and each drawing and the following embodiments do not constitute a limitation on the present application.

[0036] Figure 1 is a schematic diagram of an array integrated plasma decomposition hydrogen production scheme according to an embodiment of the present application;

[0037] Figure 2 is a schematic diagram of a reactor according to an embodiment of the present application;

[0038] Figure 3 is a schematic diagram of the structure of a reactor according to an embodiment of the present application;

[0039] Figure 4 is a schematic diagram of a top cover according to an embodiment of the present application;

[0040] Figure 5 is a schematic diagram of an array needle electrode according to an embodiment of the present application;

[0041] Figure 6 is an enlarged perspective view of I in Figure 5;

[0042] Figure 7 is a schematic diagram of a membrane separation and purification of hydrogen gas according to an embodiment of the present application;

[0043] Figure 8 is a voltage-current waveform diagram of the 4-electrode array plasma for methanol decomposition to produce hydrogen;

[0044] Figure 9 is a gas production flow rate of single electrode (a) and 4-electrode array (b) plasma for methanol decomposition under the experimental parameters of AC power discharge power of 5 kHz, electrode tip angle of 10°, and main body diameter of 1.5 mm;

[0045] Figure 10 is a corresponding gas selectivity and discharge power relationship diagram under the same working conditions of Figure 8;

[0046] Figure 11 is a graph of the optimal energy consumption and system energy conversion rate of 4-electrode array plasma for methanol decomposition to produce hydrogen, wherein Figure 11(a) is the optimal energy consumption of 4-electrode array plasma for methanol decomposition to produce hydrogen, and Figure 11(b) is a graph of the system energy conversion rate as a function of discharge power.

[0047] In the figure: 1, first reactor; 2, second reactor; 3, high-voltage power supply; 4, first circuit breaker; 5, second circuit breaker; 6, three-way valve; 7, water pump; 8, waste liquid recovery device; 9, first raw material storage device; 10, second raw material storage device; 11, first electrically operated stop valve; 12, second electrically operated stop valve; 13, filter; 14, membrane separator; 15, waste gas recovery device; 16, hydrogen gas collector; 17, high-voltage electrode; 18, insulating sleeve fixing plate; 19, high-voltage electrode fixing plate; 20, ring electrode; 21, gas bubble; 22, cooling water inlet; 23, cooling water outlet; 24, liquid inlet; 25, waste liquid outlet; 26, exhaust port; 27, insulating sleeve; 28, metal needle electrode; 29, porous medium.

[0048] DETAILED DESCRIPTION

[0049] Embodiments of the present application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0050] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0051] Figure 1 shows a preferred embodiment of the array plasma decomposition hydrogen production system of the present application, which comprises a reactor group, a high-voltage power supply 3, a waste liquid recovery device 8, a raw material storage group, a filter 13, a membrane separator 14, a waste gas recovery device 15, and a hydrogen gas collector 16.

[0052] As shown in Figures 1, 2, 3, and 4, the reactor group comprises at least one reactor, which comprises an array electrode, a ring electrode 20, a liquid inlet 24, a waste liquid outlet 25, and a gas outlet 26. The gas outlet 26 of the reactor is connected in sequence to the inlet of the filter 13 and the membrane separator 14 through a pipeline, and the outlet of the membrane separator 14 is connected to the waste gas recovery device 15 and the hydrogen gas collector 16, respectively. The liquid inlet 24 of the reactor is connected to the raw material storage group through a pipeline, and an electrically operated stop valve is provided on the pipeline between the liquid inlet 24 and the raw material storage group. The raw material storage group is used to provide liquid fuel for the reactor group. The filter 13 is used to filter out water and reaction liquid vapor in the gas. The membrane separator 14 is used to separate hydrogen gas mixture, and the purified hydrogen is stored in the hydrogen gas collector 16, and the remaining gas is stored in the waste gas recovery device 15.

[0053] The reactor is provided with an array electrode and a ring electrode 20. The array electrode is arranged at the bottom of the reactor, and the ring electrode 20 is located above the array electrode. The ring electrode 20 is connected to a metal wire ground, and the array electrode is connected to the high-voltage power supply 3.

[0054] As shown in Figures 5 and 6, the array electrode comprises a plurality of high-voltage electrodes 17 arranged in an array. The high-voltage electrode 17 comprises an insulating sleeve 27 and a metal needle electrode 28. The insulating sleeve 27 is sleeved on the metal needle electrode 28. The upper end of the insulating sleeve 27 is tightly embedded with a porous medium 29 with catalytic properties. The structure of the high-voltage electrode 17 is the core and key of the present application, which determines the hydrogen production speed and energy efficiency of hydrogen production. The upper end of the insulating sleeve 27 is fixed with a porous medium 29 with catalytic properties, which realizes the synergistic reinforcement of the catalyst and the plasma, improves the hydrogen selectivity and plasma energy utilization efficiency, and prolongs the service life of the needle electrode. In addition, the small gas bubbles generated from the porous medium 29 greatly increase the interfacial area, which can increase the number of discharges per unit time, accelerate the decomposition of liquid fuel, and reduce the energy consumption of hydrogen production.

[0055] The number of high-voltage electrodes 17 can be adjusted according to the actual demand for hydrogen. The upper end of the high-voltage electrode 17 is always immersed in the reaction liquid during the hydrogen production reaction process. Preferably, the distance between individual high-voltage electrodes 17 is controlled to be more than 3 mm, which ensures that the generated plasma bubbles have little mutual influence and guarantees that the bubbles do not aggregate when hydrogen is produced.

[0056] In one specific embodiment of the present application, preferably, the tube opening of the insulating sleeve 27 is flush with the tip of the metal needle electrode 28 in the horizontal direction; if the metal needle electrode 28 is too long, the insulating sleeve 27 cannot effectively protect it, and in this case, the insulating sleeve 27 is equivalent to a heating rod, which increases the energy dissipation of the system; if the metal needle electrode 28 is too short, the discharge mode will change, and the glow discharge mode will be dominant, which weakens the hydrogen production effect, and the plasma bubble produced will be smaller, which means that the interface area is reduced, which is not conducive to the reaction.

[0057] Preferably, the insulating sleeve 27 is arranged in an array on the insulating sleeve fixing plate 18, which is arranged at the bottom of the reactor and is sealingly arranged with the wall surface around the reactor; the metal needle electrode 28 is arranged in an array on the high-voltage electrode fixing plate 19, and the insulating sleeve fixing plate 18 is located above the high-voltage electrode fixing plate 19.

[0058] The high-voltage electrode fixing plate 19 is insulated, and the arrangement mode of all the metal needle electrodes 28 on the high-voltage electrode fixing plate 19 is consistent with the arrangement mode of the insulating sleeve 27 on the insulating sleeve fixing plate 18, which ensures that all the metal needle electrodes 28 can be accurately inserted into the insulating sleeve 27 after the two insulating plates are fitted. The insulating sleeve fixing plate 18 and the high-voltage electrode fixing plate 19 are detachable. The metal needle electrode 28 can be replaced after being damaged.

[0059] In one specific embodiment of the present application, preferably, the lower end of each metal needle electrode 28 on the high-voltage electrode fixing plate 19 is connected to a power supply line, and the power supply line is preferably made of copper and embedded in the insulating plate. The diameter of the copper wire meets the voltage requirement.

[0060] The high-voltage electrode 17 and the ring electrode 20 are configured to form an electrode structure; the ring electrode 20 is grounded, and its shape corresponds to the shape of the reactor, and the transverse cross-sectional area is greater than the area covered by the array electrode. Preferably, the ring electrode 20 is fixed to the reactor top cover through a metal rod.

[0061] According to the present embodiment, preferably, the inner diameter of the insulating sleeve 27 is about 4 mm, and the outer diameter is controlled to be 6-7 mm, which serves as a discharge channel for arc convergence, so that the high-energy area of the discharge is concentrated in the opening channel; the material of the insulating sleeve 27 is preferably high-hardness high-temperature-resistant insulating material such as alumina ceramic and zirconia ceramic, which is mainly considered to use conventional insulating sleeves to cause rapid temperature rise of the liquid during discharge without temperature control, which causes the escape of liquid fuel vapor along with the synthesis gas and increases the energy consumption, which is not conducive to the stable operation of the hydrogen production system. The insulating sleeve 27 made of alumina ceramic and zirconia ceramic can effectively slow down the temperature rise of the liquid during discharge and save energy.

[0062] The upper end of the insulating sleeve 27 is tightly embedded with a porous medium 29 with catalytic properties, which realizes the synergistic reinforcement of the catalyst and the plasma, so as to improve the high selectivity of the target product and the plasma energy utilization efficiency while ensuring the efficient performance of the chemical reaction of the plasma decomposing the liquid fuel to produce hydrogen; at the same time, the porous medium 29 can induce the discharge channel to be generated along any sharp end, dispersing the local high energy concentration of the needle electrode sharp end, reducing the hydrogen production performance decay caused by carbon precipitation due to ablation and carbon bond breaking of the liquid fuel, and greatly prolonging the service life of the needle electrode; in addition, the porous medium 29 can reduce the size of the bubbles, increase the interfacial area, and increase the number of discharges per unit time, effectively improving the liquid fuel decomposition rate and hydrogen production amount.

[0063] Preferably, the porous medium 29 is made of nickel-based and copper-based catalysts, which can reduce the cost.

[0064] If the cost is not considered, the porous medium 29 can be made of rhodium-based and noble metal alloy catalysts.

[0065] Preferably, the main body diameter of the metal needle electrode 28 is 2 mm ~ 4 mm, and the needle tip curvature is 10° ~ 30°. According to the sharp end discharge effect, the smaller the curvature, the higher the electric field strength, but the shorter the service life of the electrode. The needle tip curvature of the present application can balance the electric field strength and the service life of the electrode.

[0066] According to the present embodiment, preferably, considering that the high active substances in the plasma can cause damage to the sharp end of the metal needle electrode 28, the selection of the material needs to ensure high hardness, good catalytic properties and high electrical conductivity, therefore the material for processing the sharp end of the metal needle electrode 28 is platinum, and the material for processing the main body of the needle is copper or tungsten. This design not only makes full use of the high hardness and excellent catalytic properties of the platinum sharp end, but also effectively controls the cost.

[0067] The reactor group includes a first reactor 1 and a second reactor 2; the exhaust port 26 of the first reactor 1 is connected to the inlet of a filter 13 and a membrane separator 14 through a pipeline in sequence, the outlet of the membrane separator 14 is connected to a waste gas recovery device 15 and a hydrogen gas collector 16 respectively; the liquid inlet 24 of the first reactor 1 is connected to a first raw material storage device 9 through a pipeline, and a first electrically operated stop valve 11 is arranged on the pipeline between the liquid inlet 24 and the first raw material storage device 9 to adjust the liquid inlet flow.

[0068] The second reactor 2 is identical in structure to the first reactor 1; the exhaust port 26 of the second reactor 2 is connected in sequence with a filter 13 and an inlet of a membrane separator 14 through a pipeline, an outlet of the membrane separator 14 is connected with a waste liquid recovery device 15 and a hydrogen gas collector 16 respectively; a liquid inlet 24 of the second reactor 2 is connected with the second raw material storage device 10 through a pipeline, and a second electrically operated stop valve 12 is arranged on the pipeline between the liquid inlet 24 and the second raw material storage device 10 to adjust the liquid inlet flow.

[0069] A first circuit breaker 4 is arranged on a line through which the array electrode of the first reactor 1 is connected with the high-voltage power supply 3; a second circuit breaker 5 is arranged on a line through which the array electrode of the second reactor 2 is connected with the high-voltage power supply 3.

[0070] According to the embodiment, preferably, the high-voltage power supply 3 can use an alternating current or pulse power supply; according to the liquid phase discharge principle, the discharge mode changes with the change of voltage; in order to ensure that the liquid fuel maintains the sliding arc discharge mode, a strong enough electric field needs to be provided, so the highest voltage of the high-voltage power supply 3 needs to reach 30 kV; at the same time, the high-voltage power supply 3 needs to use an oscilloscope equipped with voltage and current probes to record the electric signal, so as to realize the control of the liquid fuel decomposition reaction rate and the hydrogen production effect.

[0071] According to the embodiment, preferably, the ring electrode 20 is made of stainless steel, and metal thin rods of the same material are arranged on both sides of the ring electrode 20, which are suspended and fixed on the flange cover and are located above the liquid surface and in the gas phase, and are connected with a metal wire for grounding treatment; the ring electrode 20 is always submerged in the reaction liquid during the reaction process; by adjusting the length of the metal thin rods in the reactor, the vertical distance between the needle-ring electrodes can be controlled, and then the discharge mode can be adjusted.

[0072] Preferably, the system further comprises a waste liquid treatment system; the waste liquid treatment system comprises a waste liquid recovery device 8, a three-way valve 6 and a water pump 7; two inlets of the three-way valve 6 are connected with the waste liquid outlet 25 of the first reactor 1 and the waste liquid outlet 25 of the second reactor 2 respectively through a communication pipeline, and an outlet of the three-way valve 6 is connected with a communication pipeline of the waste liquid collector 8; the water pump 7 is arranged on a pipeline connecting the outlet of the three-way valve 16 with the inlet of the waste liquid recovery device 8. According to the embodiment, the communication pipeline is insulated, and the construction material must have good dissolution resistance and corrosion resistance, so as to avoid damage caused by reaction with the waste liquid.

[0073] The waste liquid collector 8 is arranged between the series connection paths of the first reactor 1 and the second reactor 2, and the three are connected through the three-way valve 6 and a pipeline system; a safety valve is arranged on the pipeline system; the water pump 7 is arranged between the three-way valve 6 and the waste liquid collector 8, and the main function of the water pump 7 is to provide power to transport the waste liquid (mainly water) generated in the first reactor 1 or the second reactor 2 due to long-time reaction to the waste liquid collector 8.

[0074] Preferably, the circulating cooling temperature control system is also included, which comprises a cooling box, a cooling water inlet and a cooling water outlet; the cooling water inlet is arranged on the upper end of the side of the cooling box; and the cooling water outlet is arranged on the lower end of the side of the cooling box. The reactor of the reactor group is composed of two layers of sleeves, and the space between the two layers of sleeves is connected with the cooling water inlet 22 and the cooling water outlet 23, respectively. The circulating cooling temperature control system controls the temperature by circulating cooling water. The circulating cooling water cools and controls the temperature of the high-temperature environment generated in the reaction process. Preferably, the optimal temperature in the reactor is about 35 ℃.

[0075] In one specific embodiment of the present application, the first reactor 1 and the second reactor 2 are used alternately, because the high-activity substances generated in the discharge process may cause electrode loss, and the electrode needs to be replaced after a long time of reaction; in addition, a certain amount of waste liquid may accumulate in the reactor after a long time of reaction, and needs to be discharged regularly. Therefore, the reactor needs to be stopped when the electrode is replaced or the waste liquid is discharged, and another reactor needs to be started. By alternately using the two reactors, the plasma decomposition hydrogen production reaction system can be ensured to operate continuously and efficiently.

[0076] According to the present embodiment, the first reactor 1 and the second reactor 2 are identical in shape and size, and are processed from the same insulating material; considering that the biomass liquid fuel may have solubility and corrosion to certain materials, for example, methanol is a very strong solvent and can dissolve many organic and inorganic substances, therefore, the construction material of the storage tank must have good solubility and corrosion resistance to avoid reaction with the fuel and cause damage; in addition, considering that the reactor needs to be able to withstand the pressure of the internal fuel, therefore, the reactor needs to have good pressure resistance to prevent rupture or leakage.

[0077] In one specific embodiment of the present application, the liquid inlet 24 is arranged on the upper end of the side of the top cover; the first raw material storage tank 9 and the second raw material storage tank 10 cooperate with the pipeline flow valve first electric shut-off valve 11 and the second electric shut-off valve 12 to provide liquid fuel for the first reactor 1 and the second reactor 2 from the liquid inlet, respectively; the liquid outlet 25 is arranged on the side of the bottom of the reactor and is communicated with the waste liquid collector 8, and is used to discharge the waste liquid generated in the long-time reaction process; the gas outlet 26 is arranged at the center of the top cover of the reactor; the top cover is arranged on the top of the reactor and is sealed and connected with the reactor through a flange; the gas product post-processing part includes a filter 13 and a membrane separator 14, the filter 13 mainly filters out the water and liquid fuel vapor in the gas, and the gas membrane separator 14 is mainly used for purifying hydrogen in the mixed gas, as shown in FIG. 7.

[0078] According to the embodiment, preferably, since the mixed gas mainly contains hydrogen and carbon monoxide, the molecular sizes of the two gases are similar, and therefore a conventional polymer film is not suitable for purifying hydrogen; a metal film has high hydrogen permeability and selectivity, and is a film material suitable for purifying hydrogen; and a nanopore film has a nanopore structure, and can realize efficient separation of hydrogen by adjusting the pore size and surface chemical properties, and can also be used as a hydrogen purification film material of the application.

[0079] According to the embodiment, preferably, according to the hydrogen concentration requirement, a multi-stage membrane separation system can also be used to realize higher standard hydrogen purification by combining different types of membranes.

[0080] Preferably, the membrane separator 14 selects a metal film, a nanopore film, or uses a multi-stage membrane separation system; the hydrogen collector 16 is connected with the membrane separator 14, and is used to collect the purified hydrogen; and the waste gas collector 15 is connected with the membrane separator 14, and is used to recover the gas after the hydrogen is purified by the membrane separator, since the main component of the gas is carbon monoxide and a small amount of alkane, and carbon monoxide is one of important chemical raw materials and has wide application in industrial production, the recovered carbon monoxide can be reused as a resource.

[0081] A method for producing hydrogen according to the array plasma decomposition system, comprising the following steps:

[0082] The raw material reservoir group provides liquid fuel to the reactor group, after the liquid fuel enters the reactor through the liquid inlet 24 to a certain liquid level, the circulating cooling temperature control system is started to control the temperature; the high-voltage power supply 3 is turned on, and an oscilloscope equipped with voltage and current probes is used to record the electrical signal, the discharge mode and intensity of the area near the metal needle electrode 28 are controlled by adjusting the applied voltage and frequency, the upper end of the high-voltage electrode 17 and the ring electrode 20 are always immersed in the reaction liquid, the upper end of the insulating sleeve 27 is tightly embedded in the porous medium 29 with catalytic properties, under the synergistic effect of the plasma and the catalyst, the liquid fuel is efficiently decomposed to produce a hydrogen mixture and dispersed in the liquid phase in the form of small bubbles, the exhaust port 26 is connected, the hydrogen mixture is filtered by the filter 13 to remove water and reaction liquid vapor in the gas, the mixed gas is purified by the membrane separator 14, and the obtained high-purity hydrogen enters the hydrogen reservoir 16, and the remaining mixed gas enters the waste gas collector 15.

[0083] Preferably, the method further comprises a reactor alternating use step:

[0084] When the first reactor 1 and the second reactor 2 need to be switched, the first reactor 1 is stopped by cutting off the first circuit breaker 4, and the second reactor 2 is started by closing the second circuit breaker 5.

[0085] In one embodiment of the present application, the working process is as follows:

[0086] First, check the safety and sealing of the system, and ensure that the power supply path, liquid supply channel, liquid discharge channel and exhaust channel are normal. Then, connect each reactor to the raw material reservoir. After the liquid fuel enters the first reactor 1 to a certain liquid level, open the circulating cooling temperature control system, close the liquid discharge pipeline valve, turn on the high-voltage power supply 3, and use an oscilloscope equipped with voltage and current probes to record the electrical signal. By adjusting the applied voltage and frequency, the liquid phase discharge mode and intensity of the area around the needle electrode 28 are controlled. During the hydrogen production reaction, the upper end of the high-voltage electrode 17 and the ring electrode 20 are always immersed in the reaction liquid. Under the synergistic effect of plasma and catalyst, the liquid fuel is efficiently decomposed to produce a hydrogen gas mixture and dispersed in the form of small bubbles in the liquid phase. Then, open the exhaust pipeline valve, and the gas produced by the plasma decomposition of the liquid fuel is filtered through the filter 13 to remove water and reaction liquid vapor, purified by the membrane separator 14, and the obtained hydrogen gas enters the hydrogen gas reservoir 16. The remaining gas after purification enters the waste gas collector 15. It should be noted that during the hydrogen production reaction, the raw material reservoir needs to continuously provide raw materials for the reactor, and the specific flow rate is adjusted by the electric shut-off valve according to the consumption speed of the liquid fuel. When the electrodes are damaged or there is accumulated waste liquid in the reactor due to long-term reaction, the waste liquid produced by long-term reaction is recycled through the communication liquid outlet 23 and the waste liquid recycler 8, and the operation of the reactor is stopped before this time. Start another reactor to keep the hydrogen production system running efficiently. Here, take the first reactor 1 switching to the second reactor 2 as an example, close the first electric shut-off valve 11 to stop the liquid supply of the first raw material reservoir 9, start the second reactor 2 by switching the first circuit breaker 4 and the second circuit breaker 5, and repeat the above operation to keep the hydrogen production system running efficiently; the replacement of electrodes can be achieved by removing the high-voltage electrode fixing plate 19; when the waste liquid is discharged, open the liquid discharge pipeline valve and start the water pump 7 to provide power to pump out the waste liquid into the waste liquid collector 8.

[0087] In one embodiment of the present application, taking methanol as an example, the chemical reaction path and principle occurring in the technical solution of the present application are mainly as follows:

[0088] The reaction equation of plasma decomposition of methanol to produce hydrogen gas is:

[0089] CH3OH→H2+CO+CO2+C m H n (1)

[0090] In the initial stage of liquid-phase discharge plasma excitation, high-energy electrons bombard the phase interface, causing methanol decomposition. The CO bond of methanol preferentially breaks and generates ×CH3 and ×OH radicals (Equation 2), while H× is generated by the breaking of CH and OH bonds (Equations 3 and 4). The energies required for the breaking of CH, CO, and OH bonds are 401.9 kJ / mol, 384.9 kJ / mol, and 440.2 kJ / mol, respectively. ×OH and H× radicals are the main active groups in the methanol decomposition process, playing two roles: (1) the two radicals can react on the interface or collide with intermediate products to excite and decompose them, which can maintain and further promote plasma excitation; (2) the combination between H× is the main source of hydrogen (-104.2 kcal / mol, 298.15 K), and H× can also combine with ×OH to generate H2O (-119.3 kcal / mol, 298.15 K).

[0091] CH3OH + e → ×CH3 + ×OH + e (2)

[0092] ×CH3+e→×CH2+H×+e (3)

[0093] ×CH2+e→×CH+H×+e (4)

[0094] CH3OH + e → CH3O× + H× + e (5)

[0095] CH3OH + e → ×CH2OH + H × + e (6)

[0096] CH2OH + e → CH2O + H2 + e (6)

[0097] CH3OH + e → ×CH2 + H2O + e (7)

[0098] The products of methanol dehydrogenation include methanol radicals (×CH3OH) and methoxy radicals (CH3O×), which further decompose in the discharge region to produce H× and ×OH free radicals.

[0099] CH3OH + H× → CH2OH + H2 (8)

[0100] CH3OH + H× → CH3O× + H2 (9)

[0101] CH3OH + ×OH → ×CH2OH + H2O (10)

[0102] CH3OH + ×OH → CH3O × + H2O (11)

[0103] Formaldehyde (CH2O) and aldehyde group (CHO) are the key intermediates in methanol decomposition. The main source of CO is the decomposition of aldehyde group (12-15). Further, CO can be converted to CO2 (16) under the strong oxidation of hydroxyl radicals, and CH4 can be produced by the combination of CH3 and Hx. Since the reactions of CO2 and CH4 are the final reactions in methanol decomposition, the contents of these two gases in the gas phase products are very low. It should be noted that the actual chain reactions in methanol decomposition are extremely complex, and only some of the main reactions are given here to represent the mechanism of plasma enhancement:

[0104] CH2O + Hx→ CHO + H2 (12)

[0105] CH3O + xOH→ CHO + H2O (13)

[0106] CHO + e→ CO + Hx+ e (14)

[0107] CHO + Hx→ CO + H2 (15)

[0108] CHO + xOH→ CO + H2O (16)

[0109] CO + xOH→ CO2 + Hx (17)

[0110] CH3 + Hx→ CH4 (18)

[0111] Figure 8 is a voltage-current waveform diagram of the four-electrode array plasma for hydrogen production from methanol decomposition. The peak current can reach 1008 mA, and the peak power is 1123.2 W. The gas phase products of plasma decomposition of methanol for hydrogen production are mainly H2, CO, and a small amount of hydrocarbons, which indicates that the reaction is mainly derived from the breaking of C-H (4.302 eV) and O-H (4.824 eV) chemical bonds in methanol. The liquid phase discharge can produce a large amount of high-energy electrons of 3-20 eV, which meets the conditions required to initiate these reactions.

[0112] Figure 9(a) is the relationship between the single electrode gas production flow rate and gas selectivity and the discharge power under the experimental parameters of an alternating current power discharge power of 5 kHz, an electrode tip angle of 10°, and a main body diameter of 1.5 mm. The gas production flow rate increases with the increase of the discharge power. At 51.79 W, the minimum syngas flow rate is 684.44 mL / min, and the H2flow rate is 444.69 mL / min. As the discharge power increases to 99.95 W, the maximum syngas flow rate is 844.60 mL / min, and the H2flow rate is 544.48 mL / min. This is because the increase of power increases the electrode tip field strength, and high-energy electrons obtain more energy to collide with methanol molecules.

[0113] Figure 9(b) is the hydrogen production result of a 4-electrode array. It can be seen that the maximum gas production flow rate reaches 1822.51 mL / min, and the maximum H2flow rate is 1194.4 mL / min, which is much higher than the hydrogen production effect of a single electrode.

[0114] Figure 10 is the hydrogen production of a 4-electrode plasma decomposing methanol, and the H2and CO selectivity of the product is about 65% and about 31%, respectively. Other gas products are composed of trace amounts of CO2, CH4, C2H2, C2H6, etc. produced by incomplete decomposition of methanol. The trend of gas selectivity with the increase of discharge power is not obvious. Under the condition of liquid-phase discharge plasma, the hydrogen production ratio is close to the limit of methanol decomposition (66.67%).

[0115] Figure 11(a) is the best energy consumption of a 4-electrode array, which is 1.28 kWh / Nm 3 H2, the H2flow rate is 1188.54 mL / min. Compared with the prior art commercial hydrogen production scheme, see Renewable Energy, 2016, Manuel Gotz, Jonathan Lefebvre, Friedemann Mors. Pages 1371-1390, page 1373, the minimum energy consumption of the prior art hydrogen production scheme of alkaline electrolytic cell electrolysis of water is 4.5-7.5 Wh / Nm 3 H2, the energy conversion rate is 50-70%, and it can be seen that the energy consumption of the present application is much lower than that of the prior art hydrogen production scheme. Figure 11(b) shows the change of system energy conversion rate with the increase of discharge power. With the increase of discharge power, the system energy conversion rate increases from 70.17% to the highest value of 71.12%, and then decreases to 69.57%. This analysis only considers the power factor and only calculates the hydrogen concentration in the discharge product. Theoretically, the energy conversion efficiency of the whole reaction system is higher.

[0116] The low-temperature plasma generated by discharging of liquid phase under strong electric field can provide high activity selectivity and energy efficiency for chemical reaction, and realize the unique advantage of reaction under normal temperature and pressure, which is difficult to occur under conventional conditions, and greatly enhance the interphase reaction process and mass transfer efficiency under lower energy injection. The high-energy active substances in the plasma have strong decomposition effect on liquid, and the plasma itself can act as a catalyst, which is mainly due to the extremely high electron temperature, which increases the chemical reaction rate and reduces the reaction activation energy. In addition, the coupling effect of plasma and catalyst can ensure the efficient decomposition of liquid fuel by plasma to produce hydrogen, while improving the selectivity of target product and energy utilization efficiency of plasma. Based on the characteristics of plasma-enhanced reaction process, the problems faced by current liquid fuel hydrogen production technology can be solved. The strong electric field is used to discharge plasma in liquid fuel to break chemical bonds and initiate decomposition reaction, which requires less injection energy and low energy consumption for hydrogen production process, thereby reducing the operating cost of the system. It is a new online hydrogen production technology with high efficiency and low cost.

[0117] It should be understood that although the present specification is described in terms of various embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

[0118] The above series of detailed descriptions are only specific descriptions of feasible embodiments of the present application, and are not intended to limit the protection scope of the present application. Any equivalent embodiments or changes made without departing from the spirit of the present application should be included in the protection scope of the present application.

[0119] Enter sequence listing free form description paragraph here.

Claims

1. An array plasma decomposition hydrogen production system characterized by, The reactor group, a high-voltage power supply (3), a waste liquid recovery device (8), a raw material storage group, a filter (13), a membrane separator (14), a waste gas recovery device (15) and a hydrogen gas collector (16) are included. The exhaust port (26) of the reactor is connected to the inlet of the filter (13) and the membrane separator (14) in sequence through a pipeline, and the outlet of the membrane separator (14) is connected to the waste gas recovery device (15) and the hydrogen gas collector (16) respectively; the liquid inlet (24) of the reactor is connected to the raw material storage group through a pipeline, and an electric shut-off valve is arranged on the pipeline between the liquid inlet (24) and the raw material storage group; the raw material storage group is used to provide liquid fuel for the reactor group. An array electrode and a ring electrode (20) are arranged in the reactor, the array electrode is arranged at the bottom of the reactor, and the ring electrode (20) is arranged above the array electrode; the ring electrode (20) is grounded, and the array electrode is connected to the high-voltage power supply (3).

2. The array plasma decomposition hydrogen production system of claim 1, wherein, The array electrode includes a plurality of high-voltage electrodes (17) arranged in an array. The high-voltage electrode (17) includes an insulating sleeve (27) and a metal needle electrode (28); the insulating sleeve (27) is sleeved on the metal needle electrode (28); and a porous medium (29) with catalytic properties is tightly embedded in the upper end of the insulating sleeve (27).

3. The array plasma decomposition hydrogen production system of claim 2, wherein, The porous medium (29) is made of nickel-based and copper-based catalysts.

4. The array plasma decomposition hydrogen production system of claim 2, wherein, The insulating sleeve (27) is arranged in an array on an insulating sleeve fixing plate (18), the insulating sleeve fixing plate (18) is arranged at the bottom of the reactor and is sealingly arranged with the wall surface of the reactor; and the metal needle electrode (28) is arranged in an array on a high-voltage electrode fixing plate (19), the insulating sleeve fixing plate (18) is arranged above the high-voltage electrode fixing plate (19).

5. The array plasma decomposition hydrogen production system of claim 2, wherein, The tip of the metal needle electrode (28) is made of platinum, and the main body of the metal needle electrode (28) is made of copper or tungsten; the main body of the metal needle electrode (28) has a diameter of 2 mm to 4 mm, and the needle tip has an arc of 10° to 30°.

6. The array plasma decomposition hydrogen production system of claim 1, wherein, The reactor group includes a first reactor (1) and a second reactor (2). The exhaust port (26) of the first reactor (1) is connected to the inlet of the filter (13) and the membrane separator (14) in sequence through a pipeline, and the outlet of the membrane separator (14) is connected to the waste gas recovery device (15) and the hydrogen gas collector (16) respectively; the liquid inlet (24) of the first reactor (1) is connected to the first raw material storage (9) through a pipeline, and a first electric shut-off valve (11) is arranged on the pipeline between the liquid inlet (24) and the first raw material storage (9). The second reactor (2) has the same structure as the first reactor (1); the exhaust port (26) of the second reactor (2) is connected to the inlet of the filter (13) and the membrane separator (14) in sequence through a pipeline, and the outlet of the membrane separator (14) is connected to the waste gas recovery device (15) and the hydrogen gas collector (16) respectively; the liquid inlet (24) of the second reactor (2) is connected to the second raw material storage (10) through a pipeline, and a second electric shut-off valve (12) is arranged on the pipeline between the liquid inlet (24) and the second raw material storage (10). The array electrode of the first reactor (1) is connected with the high-voltage power supply (3) through a circuit, and a first circuit breaker (4) is arranged on the circuit.

7. The array plasma decomposition hydrogen production system of claim 6, wherein, The waste liquid treatment system comprises a waste liquid collector (8), a three-way valve (6) and a water pump (7); two inlets of the three-way valve (6) are respectively connected with the waste liquid outlet (25) of the first reactor (1) and the second reactor (2) through a communication pipeline, and an outlet of the three-way valve (6) is connected with a communication pipeline of the waste liquid collector (8); and a water pump (7) is arranged on a pipeline connecting the outlet of the three-way valve (6) with the inlet of the waste liquid collector (8).

8. The array plasma decomposition hydrogen production system of claim 1, wherein, The circulating cooling temperature control system comprises a cooling box, a cooling water inlet (22) and a cooling water outlet (23); the reactors of the reactor group are composed of two layers of sleeves, and the space between the two layers of sleeves is respectively connected with the cooling water inlet (22) and the cooling water outlet (23).

9. A method of operating the array plasma decomposition hydrogen generation system of any one of claims 1-8, wherein, The following steps are included: The raw material storage group provides liquid fuel for the reactor group, after the liquid fuel enters the reactor through the liquid inlet (24) to a certain liquid level, the circulating cooling temperature control system is started to control the temperature; the high-voltage power supply (3) is turned on, and the upper end of the high-voltage electrode (17) and the ring electrode (20) are always immersed in the reaction liquid, and the upper end of the insulating sleeve (27) is tightly embedded in the porous medium (29) with catalytic properties, under the synergistic effect of plasma and catalyst, the liquid fuel is efficiently decomposed to produce hydrogen mixture and dispersed in the liquid phase in the form of micro-bubbles, the exhaust port (26) is communicated, the hydrogen mixture is filtered through the filter (13) to remove water and reaction liquid vapor in the gas, the mixed gas is purified through the membrane separator (14), and high-purity hydrogen is obtained and enters the hydrogen storage (16), and the remaining mixed gas enters the waste gas collector (15).

10. The method of claim 9, wherein, The reactor alternation step is further included: When the first reactor (1) and the second reactor (2) need to be switched, the first reactor (1) is stopped by cutting off the first circuit breaker (4), and the second reactor (2) is started by closing the second circuit breaker (5).

Images