TWI608991B - Microwave-assisted method and apparatus for producing hydrogen - Google Patents

Description

Microwave hydrogen production method and device thereof

The invention relates to a hydrogen production method and a device thereof, in particular to a microwave hydrogen production method and a device thereof.

Because hydrogen has a high calorific value and the product after combustion is water, it is very likely to become a significant secondary energy source in the world energy arena. Countries have also invested in the research of hydrogen energy production. Take the United States as an example. Today, the United States produces about 9 million tons of hydrogen (molecular) per year, 95% of which is derived from the reaction of water vapor and hydrocarbons. The general method is to separate hydrogen gas by passing water vapor through a carbon-containing compound to which a nickel-based catalyst is attached at a high temperature and then pressurizing and adsorbing. Commonly used carbonaceous compounds are coal and natural gas, and the products that react with water vapor are hydrogen and carbon dioxide. Oxidation of hydrocarbons is another thermal reaction production process that uses a limited amount of oxygen at high temperatures through hydrocarbons. The most commonly used hydrocarbon is methane, and the reaction products are hydrogen and carbon dioxide. Because of the need for pure oxygen, the cost is higher. However, the above methods all produce a large amount of carbon dioxide, which causes environmental problems in the greenhouse effect.

In addition, electrolyzed water is a relatively simple method in which hydrogen ions are reduced at the cathode to generate hydrogen, and hydroxide ions are oxidized at the anode to generate oxygen. However, this method consumes too much power. The electrode voltage of the electrolyzed water is 1.23V, so the electricity consumption for producing 1 kilogram of hydrogen is about 32.9 degrees, and the power of 1 degree is equal to 3.6 million joules. Therefore, electrolyzed water produces hydrogen, which is only suitable for electricity in low-cost areas such as hydroelectric power generation and off-peak, or in laboratories.

For example, in the Invention Patent No. I352687 of the Republic of China Invention Bulletin No. I352687, "A device and method for generating hydrogen in a microwave", the device disclosed includes a feeding element, a microwave heater, a microwave control box, A reaction tube, and an outlet element, wherein the feeding element has a three-inlet configuration, and the three inlet ports allow gas, liquid and heat sensors to enter the reaction tube individually for chemical reaction and detection of reaction temperature. The microwave control box has a heat sensor, a temperature setter, a power controller, a power display and a power switch, the heat sensor can detect the reaction temperature, the temperature setter can set the reaction temperature, and the power controller will be measured according to the heat sensor. The temperature signal is adjusted for power to heat the reactants to the set reaction temperature, the power display can display the power output of the microwave heater, and the power switch can control the power of the heating system. The disclosed method comprises the steps of: (a) feeding the gas and the liquid at a fixed flow rate to the reactor by the same direction of the microwave heating reaction device; (b) passing the reaction liquid and the gas through the heat storage medium; c) starting the microwave heater, setting the reaction temperature to 350 ° C to 550 ° C, so that the reactants maintain a fixed heating temperature in the catalyst bed; (d) allowing the reactants to react through the catalyst bed, and rapidly producing hydrogen . By the operation of the device and proper feed control, and in combination with the action of the catalyst, the purpose of generating hydrogen can be achieved in a very short reactor start-up and heating time.

However, the occurrence of the catalytic reaction of the above-mentioned Invention No. 1352687 is limited by the surface area of the catalyst bed, so that the catalytic efficiency is not satisfactory.

Another example is the new patent of the Republic of China New Bulletin No. M394324, "A Plasma System for Hydrogen and Oxygen Production", which discloses that the appropriate water is stored in a storage container, and then the pump is used to feed the water in the storage container. In the hydrogen-oxygen decomposition unit, the ultrasonic water is turned into a very small atomized water molecule by using an ultrasonic oscillator, a high-temperature gas, and a plasma, and then heated and evaporated into a gas, and then the plasma is decomposed into ionized hydrogen and oxygen by plasma. This provides an auxiliary fuel for general fuel (gasoline or gas) combustion to reduce fuel (gasoline or gas) losses.

However, the above-mentioned new patent No. M394324 uses the ultrasonic oscillator to generate water atomization effect, but the excitation source of the reaction is the use of a highly energy-consuming plasma system, and also lacks the catalytic reaction of the catalyst, therefore, the catalytic efficiency is not ideal.

Accordingly, it is an object of the present invention to provide a microwave hydrogen production method which is low in energy consumption and high in hydrogen production efficiency.

Another object of the present invention is to provide a microwave hydrogen generating apparatus which is easy to handle and has high hydrogen production efficiency.

Thus, the microwave hydrogen production method of the present invention comprises the following steps (a) to (b): (a) uniformly dispersing the raw material and the catalyst to avoid sedimentation; and (b) passing the uniformly dispersed raw material and the catalyst through a mist. The atomization device is atomized to form a droplet state and then input into a microwave resonance reaction unit, and the raw material in the microwave resonance reaction unit can continue to undergo microwave action to further disintegrate into smaller-scale clusters or even directly pyrolyze hydrogen production. In addition, the droplet can simultaneously receive the stimulated emission electrons generated by the activation of one or more microwave antennas disposed in the microwave resonance reaction unit by being excited by the microwave, thereby achieving droplets or clusters in a state of high charge density. Hydrogen is produced by making the cracking easier, and the entire process can be catalyzed by the surface of the catalyst, so that the activation energy required for the cracking reaction is lowered to achieve high efficiency and hydrogen is produced and output for use.

In another aspect, the microwave hydrogen generation device of the present invention comprises a microwave resonance reaction unit, a DC power supply, a storage device, an atomization device, a microwave generator, and a gas storage device.

The microwave resonant reaction unit has a microwave resonant cavity and one or more microwave antennas disposed in the microwave resonant cavity.

The DC power supply is electrically connected to the metal electrodes, and the DC power supply can provide a potential difference to the microwave antennas.

The storage device includes a storage bucket disposed outside the microwave resonance reaction unit for containing the raw material and the catalyst, and a storage tank is disposed in the storage bucket for extending into the storage bucket to perform stirring The raw material and the catalyst in the storage tank are uniformly dispersed to avoid the settling stirring element.

The atomizing device is connected between the storage tank and the microwave resonance reaction unit, so that the uniformly dispersed raw materials and the catalyst are atomized to form a droplet state and then input into the microwave resonant cavity.

The microwave generator is disposed outside the microwave resonance reaction unit and can emit a microwave signal in the microwave cavity, so that the raw material in the microwave cavity can not only continue to receive microwave action but further disintegrate into smaller-scale groups. The clusters even directly pyrolyze hydrogen production. In addition, the droplets can simultaneously receive the stimulated emission electrons generated by the activation of the microwave antennas, thereby achieving droplets or clusters in a state of high charge density, thereby making the cracking easier. Hydrogen is produced while the entire process can be catalyzed by the surface of the catalyst, so that the activation energy required for the cracking reaction is lowered to achieve high efficiency and hydrogen is produced and output for use.

The gas storage device is hydrogen gas which is connected to the outside of the microwave resonance reaction unit and is collected and collected in the microwave resonance reaction unit.

The effect of the invention is that the raw material and the catalyst are fed into the microwave resonance reaction unit by means of atomization, so that they can be uniformly dispersed in the entire microwave resonance reaction unit, and the occurrence of the catalytic reaction is no longer limited by the traditional touch. The surface area of the media bed can greatly improve the catalytic efficiency. In addition, the microwave resonance effect in the microwave resonance reaction unit also has the multiple benefits of simultaneously activating the raw material and effectively exciting the excited electron emission on the surface of the microwave antenna, and assisting the decomposition of the raw material to produce hydrogen with the aid of the catalyst. Small and efficient.

11‧‧‧Microwave resonance reaction unit

111‧‧‧Microwave Resonator

112‧‧‧Microwave antenna

12‧‧‧DC power supply

13‧‧‧Storage device

131‧‧‧ storage bucket

132‧‧‧ stirring element

14‧‧‧Atomizing device

15‧‧‧Microwave generator

16‧‧‧ gas storage device

17‧‧‧Waveguide

18‧‧‧High pressure pump

[First Diagram] is a schematic view showing an embodiment of the microwave hydrogen generation apparatus of the present invention.

Other features and effects of the present invention will be apparent from the following description of the drawings.

Referring to the first figure, an embodiment of the microwave hydrogen production method of the present invention comprises the following steps (a) to (b).

In the step (a), the raw material and the catalyst are prepared, wherein the raw material is water, and the catalyst is a substance capable of forming a chemical force (for example, a hydrogen bond) with a bonding force of more than 25 KJ/mol or more in the water molecule. In this embodiment, the catalyst is an iron oxide powder of a micron to nanometer scale, and the mixing ratio of the raw material to the catalyst is determined by the size of the resonant cavity, the feed rate, the microwave intensity, and the number of the microwave antenna 112 (described in detail later). Adjusted by factors such as location to optimize efficiency, the concentration range is from 100ppm to 20%. The raw materials and the catalyst are first placed in a storage tank 131, and the raw materials and the catalyst can be uniformly dispersed by a stirring action of the stirring member 132 disposed in the storage tank 131 to prevent sedimentation.

In the step (b), the raw material and the catalyst which have been uniformly dispersed in the storage tank 131 are fed into an atomizing device 14 by a high pressure pump 18. It is specifically stated here that the raw material and the catalyst can also be fed into the atomizing device 14 by pneumatic means. The atomizing device 14 is used to atomize the uniformly dispersed raw material and the catalyst to form a droplet state, and is further input into a microwave resonance reaction unit 11, the microwave resonance reaction unit 11 has a microwave resonant cavity 111, and one or more The microwave antenna 112 in the microwave cavity 111 is composed of a metal electrode. A microwave generator 15 is connected to the outside of the microwave resonance reaction unit 11, and the microwave generator 15 and the microwave cavity 111 are connected by a waveguide 17. The microwave antennas 112 are electrically connected to the DC power supply 12, and the DC power supply 12 generates a potential difference between the microwave antennas 112 and the original materials, so that the microwave antennas 112 can be generated in the microwave resonant cavity 111. Microwave resonance, whereby the microwave energy can not only activate the raw material, but also effectively excite the microwave antenna to generate stimulated emission electrons on the surface, so that the raw materials in the microwave resonant cavity 111 can not only continue to receive microwave action but further disintegrate into more Small-scale clusters can even produce hydrogen by direct thermal cracking, and can simultaneously accept the stimulated emission electrons, thereby generating a hydrogen gas through a high charge density crowding effect in the cluster to make the cracking more likely to occur. At the same time, the whole process can be catalyzed by the surface of the catalyst, so that the activation energy required for the cracking reaction is reduced to achieve high efficiency and hydrogen is produced. Available for use. The microwave frequency outputted by the microwave generator 15 is 800 MHz to 100 GHz, and is adjusted according to the catalyst concentration, the cavity size of the microwave resonant cavity 111, and the position and number of the metal electrodes. The generated hydrogen gas can be extracted into a gas storage device 16 by using a pumping pump (not shown), or can be introduced into the gas storage device 16 by a differential pressure natural exhaust method. The gas storage device 16 is provided for use.

In addition, the microwave hydrogen production method of the present invention further comprises a step (c), in which a pipeline is connected between the bottom of the microwave resonance reaction unit 11 and the storage tank 131 to settle to the microwave resonance reaction unit 11 The bottom catalyst is recycled to the storage tank 131 for recycling.

Furthermore, the microwave hydrogen generating device of the present invention comprises a microwave resonant reaction unit 11, a DC power supply 12, a storage device 13, an atomizing device 14, a microwave generator 15, and a gas storage device 16. The microwave resonance reaction unit 11 has a microwave resonant cavity 111 and one or more microwave antennas 112 disposed in the microwave resonant cavity 111. The microwave antennas 112 are composed of metal electrodes. The DC power supply 12 is electrically connected to the microwave antennas 112, and the DC power supply 12 can provide a proper potential difference between the microwave antenna 112 and the raw material. The stocking device 13 includes a storage tank 131 disposed outside the microwave resonance reaction unit 11, and a stirring element 132 disposed in the storage tank 131. The storage tank 131 is for holding raw materials and a catalyst. The agitating element 132 is configured to extend into the storage tank 131 for agitation to uniformly disperse the raw materials and the catalyst in the storage tank 131 to prevent sedimentation. The atomizing device 14 is connected between the storage tank 131 and the microwave resonance reaction unit 11 for atomizing the uniformly mixed raw materials and catalyst into a microdroplet state and inputting into the microwave resonant cavity 111. The microwave generator 15 is disposed outside the microwave resonance reaction unit 11 and is coupled to the microwave cavity 111 by a waveguide 17, and the microwave generator 15 can provide a microwave energy field in the microwave cavity 111. . In addition, the gas storage device 16 is resistant to high pressure and is connected to the outside of the microwave resonance reaction unit 11 for collecting hydrogen gas produced in the microwave resonance reaction unit 11. In addition, the microwave hydrogen generating device of the present invention may further comprise a high pressure pump 18 connected between the storage tank 131 and the atomizing device 14. Borrow this high The pressure pump 18 is used to extract the raw material and the catalyst which have been uniformly dispersed in the storage tank 131 and then sent to the atomization device 14.

Specifically, the electromagnetic wave frequency range is collectively referred to as microwave in the interval of 300 MHz to 300 GHz, and the present invention utilizes a frequency near about 2.45 GHz as an excitation source for the reaction, and the main advantages are two:

(1) The electromagnetic radiation in this band resonates with the oscillation frequency of the electron sea on the metal surface, so it can produce a good heating effect on the metal. If it acts on the metal electrode, the electrons on the surface of the metal electrode will be high due to the thermal energy generated by the resonance. Frequency oscillation activation. If a high-voltage electric field is applied to the metal electrode, its effect is only to maintain the potential difference, and the energy loss is low. With the sharpening of the shape of the metal electrode, the activated electrons at the tip end of the needle tip are formed by the repulsive effect of the high potential density. A high energy electron emission source acts as a reactor for water cracking.

(2) The electromagnetic wave in this band resonates with the rotational energy frequency of water molecules, so it is easily absorbed by water molecules to provide the rotational kinetic energy of water molecules, which will contribute to the disintegration of water clusters under the action of vigorous rotation of water molecules. The water cracking reaction can be achieved under relatively low temperature conditions. Another reaction pathway is the conversion of dynamic water molecules to each other by friction to generate thermal energy, which in turn is converted into kinetic energy of water cleavage, and the advantages of multiple reaction pathways are achieved.

In addition, the raw materials and catalysts which have been uniformly mixed are introduced into the microwave resonance reaction unit 11 in an atomized form, and the main advantages are three:

(1) Refining liquid water into micron-to-nano-sized water droplets can reduce the energy loss caused by the high-energy stimulated emission electrons on the surface of the metal electrode during the emission process, and the raw materials are Effective cross-sectional area of the electron emission source.

(2) The more the number of water cluster molecules, the more the ability to stabilize electrons in the water cluster is relatively enhanced, making the water cracking reaction less likely to occur. The atomized water droplets are light in weight and small in weight, so they can reduce the effect of gravity, increase their stagnation time in space, and are less likely to return to condensed water. The raw material after atomization has a large increase in surface area, and it is effective to reduce the molecular number of water clusters and increase the reaction rate of water splitting due to the influence of microwave or environmental influence. In addition, in the present apparatus, since the microwave antenna 112 is provided, the water droplets or water clusters in the microwave cavity 111 can be made to have high charge density particles formed by the excited emission electrons radiated from the microwave antenna 112. Helps the water cracking reaction to occur.

(3) The catalyst used in the present invention is a metal oxide, which can shield the microwave in a high-density metal oxide environment, and the atomization feeding method can not only achieve uniform dispersion of the catalyst in the reaction chamber. And the concentration change can be used to control the distribution density of the catalyst in the reaction space, thereby reducing the influence of the catalyst shielding effect.

Furthermore, the invention adopts micron to nanometer scale iron oxide powder as a catalyst for water cracking, and iron oxide can form hydrogen with water molecules, effectively weakening the binding force of oxygen atoms in water molecules to hydrogen atoms, and reducing water splitting. Reaction energy barrier. In addition, an oxide formed by iron atoms of different valences can be used as a redox interconnecting group for the reaction to achieve an electron transfer reaction, thereby achieving the advantages of a multiple reaction pathway.

In summary, the microwave hydrogen production method and apparatus of the present invention, by the above design, the raw materials and the catalyst are sent to the microwave resonance reaction unit 11 by atomization, so that they can be uniformly dispersed throughout the microwave resonance reaction unit 11. The occurrence of the catalytic reaction will no longer be limited by the surface area of the conventional catalyst bed, which can greatly improve the catalytic efficiency. In addition, the microwave resonance reaction unit 11 has a metal electrode which can be used as a microwave antenna. After receiving the microwave drive, the metal electrode can oscillate and radiate the excited emission electrons to participate in the water cracking hydrogen production reaction, and the catalyst is assisted to make the original The pyrolysis hydrogen production reaction of the material has the effects of low energy consumption and high efficiency.

In view of the foregoing description of the embodiments, the operation and the use of the present invention and the effects of the present invention are fully understood, but the above described embodiments are merely preferred embodiments of the present invention, and the invention may not be limited thereto. Included within the scope of the present invention are the scope of the present invention.

11‧‧‧Microwave resonance reaction unit

111‧‧‧Microwave Resonator

112‧‧‧Microwave antenna

12‧‧‧DC power supply

13‧‧‧Storage device

131‧‧‧ storage bucket

132‧‧‧ stirring element

14‧‧‧Atomizing device

15‧‧‧Microwave generator

16‧‧‧ gas storage device

17‧‧‧Waveguide

18‧‧‧High pressure pump

Claims (8)

A microwave hydrogen production method comprising: (a) uniformly dispersing a raw material and a catalyst to avoid sedimentation; and (b) atomizing the uniformly dispersed raw material and the catalyst by an atomizing device to form a droplet state, and then inputting a In the microwave resonance reaction unit, the raw material in the microwave resonance reaction unit can continue to undergo microwave action to further disintegrate into smaller-scale clusters or even directly pyrolyze hydrogen production, and further, the droplets can simultaneously receive the microwaves. One or more microwave antennas in the resonance reaction unit act on the excited emission electrons generated by activation after microwave resonance excitation, thereby achieving droplets or clusters in a state of high charge density, so that the cracking action is more easily performed to generate hydrogen gas, and at the same time Throughout the whole process, the surface catalysis of the catalyst can be used to reduce the activation energy required for the cracking reaction to achieve high efficiency and to produce hydrogen for output. The raw material is water, and the catalyst can form oxygen atoms with water molecules. a material having a bonding force greater than or equal to 25 KJ/mol, wherein the microwave resonance reaction unit is provided with more than one microwave antenna, The microwave antenna is composed of a metal electrode and is electrically connected to the DC power supply. The DC power supply provides a potential difference between the metal electrodes and the water molecules, so that the metal electrodes can be in the microwave resonance reaction unit. The raw material which has been uniformly dispersed and formed into a droplet state is effectively subjected to a cracking hydrogen production reaction with the aid of a catalyst. The microwave hydrogen production method according to claim 1, wherein in the step (b), the catalyst is a micron to nanometer scale iron oxide powder. The microwave hydrogen production method according to claim 2, wherein in the step (b), the microwave frequency is 800 MHz to 100 GHz. The method for microwave hydrogen generation according to claim 1, wherein in the step (b), the hydrogen produced by the pump is pumped out and introduced into a gas storage device. The method for microwave hydrogen generation according to claim 1, wherein in the step (b), the produced hydrogen gas is introduced into a gas storage device by a differential pressure natural exhaust method. The microwave hydrogen production method according to claim 5, wherein in the step (a), the raw material and the catalyst are first placed in a storage tank, and the stirring is provided in the storage tank. The agitation of the element enables the raw material and the catalyst to be uniformly dispersed to avoid sedimentation; in addition, the microwave hydrogen production method further comprises a step (c) in which the catalyst settled to the bottom of the microwave resonance reaction unit is recovered to The storage tank. A microwave hydrogen generating device comprising: a microwave resonant reaction unit having a microwave resonant cavity; and one or more microwave antennas disposed in the microwave resonant cavity; a DC power supply, electrically connected to the microwave antennas, The DC power supply can provide a potential difference to the microwave antennas; a storage device includes a storage tank disposed outside the microwave resonance reaction unit for containing the raw materials and the catalyst, and a storage tank And a stirring element for extending into the storage tank to perform stirring to uniformly disperse the raw materials and the catalyst in the storage tank to avoid sedimentation; an atomizing device is connected to the storage drum and the microwave resonance Between the reaction units, the uniformly dispersed raw materials and the catalyst are atomized to form a droplet state and then input into the microwave resonant cavity; a microwave generator is disposed outside the microwave resonance reaction unit and can be used for the microwave resonant cavity A microwave signal is emitted internally, so that the raw materials in the microwave resonant cavity can not only continue to undergo microwave action but further disintegrate into smaller scale clusters or even direct thermal cracking. Hydrogen, in addition, the droplets can simultaneously receive the action of the excited emission electrons generated by the activation of the microwave antennas, thereby achieving droplets or clusters in a state of high charge density, so that the cracking is easier to generate and hydrogen is generated. Throughout the whole process, the surface catalysis of the catalyst can be utilized to reduce the activation energy required for the cracking reaction to achieve high efficiency and to produce hydrogen for output; and a gas storage device is connected to the outside of the microwave resonance reaction unit and used for The hydrogen produced in the microwave resonance reaction unit is collected. The microwave hydrogen generating device of claim 7, wherein the microwave generator and the microwave resonant cavity are connected by a waveguide.