CN111569803A - Device and method for catalytically reforming greenhouse gas by using plasma - Google Patents

Abstract

The device comprises a reactor, wherein the reactor comprises a first cylinder and a second cylinder which are coaxially nested, inner electrodes connected with a pulse power supply are arranged on the axes of the two cylinders, a grounding outer electrode is arranged on the outer side surface of the second cylinder, and a catalyst is filled in a gap between the first cylinder and the second cylinder; a magnetic stirring plate vertical to the bottom surface of the reactor is arranged at the position, close to the bottom surface of the reactor, of the outer side surface of the first cylinder, a plurality of electromagnetic assemblies matched with the stirring plate are arranged on the outer side surface of the second cylinder, and the polarity of one end, far away from the first cylinder, of the stirring plate is the same as that of one side, close to the second cylinder, of the electromagnetic assemblies when the electromagnetic assemblies are electrified; according to the method, the magnetic stirring equipment is arranged at the bottom of the reactor, the magnetic field of the magnetic stirring equipment is fully utilized, the movement of charged particles in a discharge air gap is changed, the retention time of the charged particles in a discharge interval is prolonged, the reaction of methane and carbon dioxide is promoted, and the greenhouse gas reforming efficiency is improved.

Description

A device and method for plasma catalytic reforming of greenhouse gases

technical field

The present disclosure relates to the technical field of catalytic reforming of greenhouse gases, and in particular, to a device and method for plasma catalytic reforming of greenhouse gases.

Background technique

The statements in this section merely provide background related to the present disclosure and do not necessarily constitute prior art.

With the development and utilization of such fossil energy, there is a global greenhouse effect. The increasing content of greenhouse gases such as carbon dioxide and methane is the main cause of global warming, and it is also the raw material gas for industrial production of syngas, olefins and other high-value chemicals. In the face of the long-standing greenhouse effect, it is important for the national economy and the Key scientific and technological problems that urgently need to be solved in social development.

Plasma consists of neutral atoms, molecules, free radicals, excited states, ions and electrons. For the resource utilization of inert gases such as methane and carbon dioxide, plasma can be used for activation to reduce the activation energy barrier of the reaction and promote the occurrence of the reaction. Plasma catalysis, which combines plasma and catalyst, can utilize the interaction and synergistic effect of plasma and catalyst to improve energy conversion efficiency, and has broad applications in the preparation of raw materials for syngas, olefins and other high-value chemicals prospect.

Dielectric Barrier Discharge (DBD) has low energy consumption, uniform and stable discharge, simple reactor structure, suitable for plasma catalysis under atmospheric pressure, and can also be combined with Ni/Al ₂ O ₃ , Ag/Al ₂ O ₃ , Pt A wider variety of catalysts such as /Al ₂ O ₃ , Pd/Al ₂ O ₃ , Ni/SiO ₂ , zeolites or metal organic frameworks form interactions and synergistic effects to increase the yield and selection of high-value chemicals for reforming greenhouse gases sex. Packed-bed DBDs have high electric field strength and electron energy, and are capable of more frequent electron impact ionization, excitation, decomposition, and other plasma reactions, resulting in abundant charged particles, radicals, and excited-state particles, which are activated with higher energy efficiency Plasma catalysis. The high-voltage inner electrodes of DBD reactors are generally smooth metal rod electrodes, threaded electrodes and coil electrodes, of which smooth metal rod electrodes are most commonly used.

The inventors of the present disclosure found that, in the existing dielectric barrier discharge method, the residence time of electrons in the discharge area is short, and it is often impossible to achieve fast and efficient reforming of greenhouse gases, that is, the reaction of methane and carbon dioxide is relatively slow and takes a long time; The smooth metal rod electrode produces less high-energy electrons, the heat diffusion is not timely, and the inner cylinder of the high-voltage inner electrode bursts due to thermal expansion.

SUMMARY OF THE INVENTION

In order to solve the deficiencies of the prior art, the present disclosure provides a device and method for plasma catalytic reforming of greenhouse gases. By arranging a magnetic stirring device at the bottom of the reactor, the magnetic field can be fully utilized to change the charged particles in the discharge gap. The movement of the charged particles increases the residence time of the charged particles in the discharge interval, promotes the reaction of methane and carbon dioxide, and improves the reforming efficiency of greenhouse gases.

In order to achieve the above object, the present disclosure adopts the following technical solutions:

A first aspect of the present disclosure provides an apparatus for plasma catalytic reforming of greenhouse gases.

A device for plasma catalytic reforming of greenhouse gases, comprising a reactor, the reactor comprises a coaxially nested first cylinder and a second cylinder, the axes of the two cylinders are provided with a pulse power supply The connected inner electrode, the outer surface of the second cylinder is provided with a grounded outer electrode, and the gap between the first cylinder and the second cylinder is filled with catalyst;

The outer side of the first cylinder is provided with a magnetic stirring plate that can rotate along the first cylinder at the position close to the bottom surface of the reactor, and the outer side of the second cylinder is provided with a plurality of electromagnetic components that cooperate with the stirring plate, and the stirring plate is far away from the first cylinder. The polarity of one end of a cylinder is the same as the polarity of the side close to the second cylinder when the electromagnetic assembly is energized.

As some possible implementations, the inner electrode is an aluminum rod, and the surface of the aluminum rod is provided with a plurality of protrusions.

As a further limitation, the protrusions are all in contact with the aluminum foil on the inner surface of the first cylinder.

As some possible implementations, a plurality of stirring plates with the same angle are fixed on the outer side of the first cylindrical body along the circumferential direction, and the movement space of the stirring plates is the space between the first cylindrical body and the second cylindrical body. gap.

As some possible implementations, the magnetic stirring plate is perpendicular to the bottom surface of the reactor.

As some possible implementations, an argon storage device, a carbon dioxide storage device, and a methane storage device are also included. The argon storage device and the carbon dioxide storage device are respectively connected to the first mass flow meter through pipelines, and the methane storage device is connected through pipelines. Connected to the second mass flowmeter, the first mass flowmeter and the second mass flowmeter are respectively connected to the gas premixing tank through pipelines, and the gas premixing tank is connected to the gas inlet at the top of the reactor through pipelines.

As some possible implementations, the bottom of the reactor is provided with an air outlet, and the air outlet is sequentially communicated with a soap film flowmeter, a cold trap, a gas collection box, an air pump and a gas chromatograph through pipelines, and the chromatograph connected to the computer terminal.

As a further limitation, it also includes an oscilloscope, an air pump, an infrared thermal imager, a water pump and an AC power supply; the oscilloscope is used to display the voltage waveform at the input end of the reactor and the voltage and current waveforms at the output end in real time, and the infrared thermal imager is used to collect the reaction The real-time temperature data of the machine is transmitted to the computer terminal; the heater is used to heat the circulating oil to provide stable temperature conditions, the water pump is used to make the circulating oil reach a circulating state, and the AC power supply is used to power the magnetic stirrer.

As some possible implementations, the grounded outer electrode is a stainless steel mesh covering the outer surface of the second cylinder, and the stainless steel mesh is grounded after passing through a capacitor.

As some possible implementations, the catalyst is a Ni-Al ₂ O ₃ catalyst, and the Ni-Al ₂ O ₃ catalyst is fixed with quartz wool.

A second aspect of the present disclosure provides a method of operation of an apparatus for plasma catalytic reforming of greenhouse gases.

A working method of a device for plasma catalytic reforming of greenhouse gases, using the device for plasma catalytic reforming of greenhouse gases according to the first aspect of the present disclosure, comprising the following steps:

The pulse power is turned on, and the electromagnetic components are energized;

Before the plasma catalytic reforming of the greenhouse gas, argon gas is introduced into the gap between the first cylinder body and the second cylinder body of the reactor to reduce the catalyst in the argon discharge plasma;

A preset ratio of methane gas and carbon dioxide gas is introduced into the gap between the first cylinder body and the second cylinder body of the reactor, and discharge is performed under the action of the inner electrode;

The movement of the stirring plate generates a magnetic field, and the charged particles change their original moving paths under the action of the magnetic field, increasing the residence time of the charged particles in the discharge interval.

Compared with the prior art, the beneficial effects of the present disclosure are:

1. In the device and method described in this disclosure, a magnetic stirring device is arranged at the bottom of the reactor, and the magnetic field generated by the magnetic stirring device changes the movement of the charged particles in the discharge gap, and the charged particles change the original motion path under the action of the magnetic field. , which increases the residence time of charged particles in the discharge interval. In addition, due to the magnetoresistance effect, the resistance of the metal increases, the electrical conductivity decreases, and the energy loss of the released high-energy electrons decreases, which improves the collision reaction rate of electrons with methane and carbon dioxide.

2. In the device and method described in the present disclosure, the high-voltage inner electrode is composed of a thorn-shaped aluminum rod and an aluminum foil closely attached to the inner wall of the inner quartz glass cylinder, and the thorn-shaped structure on the aluminum rod is in close contact with the aluminum foil. This kind of electrode can obtain more high-energy electrons, expand the surface area of the electrode, enhance the reaction effect, and at the same time reduce the heat loss, so that the generated heat can be diffused in time, effectively avoiding the inner glass tube burst caused by thermal expansion of the high-voltage inner electrode. .

Description of drawings

FIG. 1 is a schematic structural diagram of an apparatus for plasma catalytic reforming of greenhouse gases provided in Embodiment 1 of the present disclosure.

FIG. 2 is a top view of the magnetic stirrer provided in Embodiment 1 of the present disclosure.

1-Argon gas cylinder; 2. Carbon dioxide gas cylinder; 3. Methane gas cylinder; 4. DBD reactor; 5. Soap film flowmeter; 6. Cold trap; 7. Gas collection box; 8. Air pump; 9. Gas phase Chromatograph; 10. Computer; 11. Nanosecond pulse power supply; 12. Oscilloscope; 13. Infrared thermal imager; 14. Water pump; 15. Heater; 16. Electromagnetic components; 17. Magnetic stirring plate; 18. AC power supply; 19. Bottom view of the magnetic stirrer.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present disclosure. 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 disclosure belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

The embodiments in this application and the features in the embodiments may be combined with each other without conflict.

Example 1:

As shown in FIG. 1 , Embodiment 1 of the present disclosure provides a device for plasma catalytic reforming of greenhouse gases, which includes four parts: a gas circuit, an electric circuit, an oil circuit and a reactor.

The gas route is composed of argon gas cylinder 1, methane gas cylinder 3, carbon dioxide gas cylinder 2, mass flowmeter, one-way valve, gas premix tank, soap film flowmeter 5, cold trap 6, and gas collection box 7.

In this embodiment, the argon gas cylinder 1 and the carbon dioxide gas cylinder 2 are respectively connected to the first mass flowmeter through pipelines, and the methane gas cylinder 3 is connected to the second mass flowmeter through pipelines, and the first mass flowmeter and the second mass flow meter are respectively connected to the gas premixing tank through pipelines, and the gas premixing tank is connected to the gas inlet at the top of the DBD reactor 4 through pipelines.

The argon gas cylinder 1 is filled with high-purity argon gas for reducing the catalyst in the argon discharge plasma before the plasma catalytic reforming of the greenhouse gas.

The methane cylinder 3 contains high-purity methane gas, and the carbon dioxide cylinder 2 contains high-purity carbon dioxide gas. The mass flow meter is used to control the ratio of methane and carbon dioxide gas, which is conducive to the generation of uniform and stable plasma. The one-way valve is used to control the one-way flow of gas. The gas premix tank is used to premix a certain proportion of methane and carbon dioxide gas. Cold traps are used to prevent reverse reactions. The gas collection box is used to collect the gases produced by the reaction.

The circuit part includes a nanosecond pulse power supply 11 , an AC power supply 18 , an oscilloscope 12 , an air pump 8 , a gas chromatograph 9 , an infrared thermal imager 13 , a heater 15 , a water pump 14 , a computer 10 , and a magnetic stirrer 19 .

The bottom of the reactor is provided with an air outlet, and the air outlet is sequentially communicated with a soap film flowmeter, a cold trap, a gas collection box, an air pump and a gas chromatograph through a pipeline, and the chromatograph is connected with a computer terminal.

The nanosecond pulse power supply is used to provide the excitation source for the device, which is connected to the inner electrode, the frequency is 0-15KHz, the output amplitude is 0-15kv, and the pulse rise time and pulse fall time are 50-500ns.

The oscilloscope is connected to the input end of the DBD reactor and the output end of the DBD reactor respectively through the high voltage probe, and the current at the output end of the DBD reactor is sensed through the Rogowski coil, which is used to display the voltage waveform of the input end of the DBD reactor and the voltage and current of the output end of the DBD reactor in real time. waveform;

The gas pump is used to extract the collected reacted products, and use a gas chromatograph for gas component analysis.

The infrared thermal imager is set on the outside of the reactor, and its probe is facing the catalyst in the reactor, and is used to collect real-time temperature data of the DBD reactor.

The outside of the reactor is provided with circulating oil, the heater is used to heat the circulating oil to provide stable temperature conditions, and the water pump is used to make the circulating oil reach a circulating state.

The AC power supply is connected to the electromagnetic component of the magnetic stirrer, which is used to provide power to the magnetic stirrer, and the magnetic stirrer is used to generate a magnetic field, change the movement of charged particles in the discharge gap, and improve the collision reaction rate of electrons with methane and carbon dioxide.

The reactor device used in this embodiment uses a coaxial cylindrical structure, including an inner cylinder with a smaller radius and an outer cylinder with a larger radius. The high-voltage inner electrode is not a traditional metal rod, but is composed of a thorn-shaped aluminum rod and an aluminum foil that is close to the inner wall of the inner quartz glass cylinder. The thorn-like structure on the aluminum rod is in close contact with the aluminum foil. This electrode can obtain more high-energy electrons, expand the surface area of the electrode, and enhance the reaction effect.

At the same time, this electrode structure has the arc-shaped outer surface of the traditional metal rod electrode, but its interior is not completely solid, but is formed by the thorn-like structure on the aluminum rod in close contact with the aluminum foil, and the setting of the aluminum foil reduces the heat On the one hand, the heat generated by the discharge can be diffused by the high thermal conductivity of the aluminum rod, and on the other hand, it can also be diffused in time through the gap between the thorn-like structures, which effectively avoids the high-voltage inner electrode caused by thermal expansion. The inner glass cylinder burst.

In this embodiment, the grounded outer electrode is covered by a stainless steel mesh, and the two dielectric barrier layers are made of quartz. The gas is passed into the gap between the two quartz materials to discharge. The gas gap was filled with Ni _{- Al2O3} catalyst and fixed with quartz wool. A ring-shaped magnetic stirrer is set at the bottom of the reactor to make full use of its magnetic field to change the movement of charged particles in the discharge gap, increase the residence time of the charged particles in the discharge interval, and promote the reaction of methane and carbon dioxide.

In this example, a magnetic stirrer is used under the catalyst, as shown in FIG. 2 , and the magnetic field of the magnetic stirrer is fully utilized to promote the decomposition of methane and carbon dioxide. The cylindrical cavity of the reactor is used as a stirring chamber for magnetic stirring, the central electrode of the reactor and the quartz medium layer wrapped on the central electrode are used as a fixed axis, and a magnetic stirring plate perpendicular to the bottom surface of the stirring chamber is installed around the fixed axis. There are several electromagnetic components in the outer annular array of the reactor. The outer polarity of the stirring plate is the same as the inner polarity when the electromagnetic components are energized. Therefore, a magnetic field will be generated under the action of a magnetic stirrer with an external AC power supply.

Optimizing the excitation power supply, supported metal catalyst, and DBD reactor of packed bed DBD in combination with a magnetic stirrer can achieve gas conversion, energy efficiency, and high-value chemical yield and selection for DBD plasma catalytic reforming of greenhouse gases Reasonable control of sex.

In this embodiment, the added magnetic field changes the motion of the charged particles in the discharge gap, and the charged particles change the original motion path under the action of the magnetic field, which increases the residence time of the charged particles in the discharge interval. In addition, due to the magnetoresistance effect, the The resistance of the metal increases, the electrical conductivity decreases, the energy loss of the released high-energy electrons decreases, and the collision reaction rate between electrons and methane carbon dioxide increases.

In this embodiment, dielectric barrier discharge plasma is used to cooperate with catalyst and magnetic field, and the ionization, excitation, decomposition and other plasma reactions of _CH4 and _CO2 by plasma are used to generate abundant charged particles, free radicals and excited state particles, and increase particles The rate of collisional reactions between them to promote the conversion of greenhouse gases.

Example 2:

Embodiment 2 of the present disclosure provides a working method of an apparatus for plasma catalytic reforming of greenhouse gases, using the apparatus for plasma catalytic reforming of greenhouse gases described in Embodiment 1 of the present disclosure, including the following steps:

The pulse power is turned on, and the electromagnetic components are energized;

Before the plasma catalytic reforming of the greenhouse gas, argon gas is introduced into the gap between the first cylinder body and the second cylinder body of the reactor to reduce the catalyst in the argon discharge plasma;

A preset ratio of methane gas and carbon dioxide gas is introduced into the gap between the first cylinder body and the second cylinder body of the reactor, and discharge is performed under the action of the inner electrode;

The movement of the stirring plate generates a magnetic field, and the charged particles change their original moving paths under the action of the magnetic field, increasing the residence time of the charged particles in the discharge interval.

The above descriptions are only preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included within the protection scope of the present disclosure.

Claims (10)

1. The device for catalytically reforming greenhouse gas by using the plasma is characterized by comprising a reactor, wherein the reactor comprises a first cylinder and a second cylinder which are coaxially nested, inner electrodes connected with a pulse power supply are arranged on the axes of the two cylinders, a grounding outer electrode is arranged on the outer side surface of the second cylinder, and a catalyst is filled in a gap between the first cylinder and the second cylinder;

the position that the lateral surface of first barrel is close to the reactor bottom surface is equipped with the magnetism stirring board that can follow the rotation of first barrel, and the lateral surface of second barrel is equipped with a plurality ofly and magnetism stirring board complex electromagnetic component, and the polarity that the one end of first barrel was kept away from to magnetism stirring board is the same with the circular telegram polarity that electromagnetic component is close to one side of second barrel.

2. The apparatus for plasma catalytic reforming of greenhouse gases as claimed in claim 1, wherein the inner electrode is an aluminum rod, and the surface of the aluminum rod is provided with a plurality of protrusions.

3. The apparatus for plasma catalytic reforming of greenhouse gases as claimed in claim 2, wherein the protrusions are each in contact with the aluminum foil of the inner surface of the first cylinder.

4. The apparatus for plasma catalytic reforming of greenhouse gases as claimed in claim 1, wherein a plurality of agitating plates having the same angle are fixed to the outer side surface of the first cylinder in the circumferential direction, and the moving space of the agitating plates is a gap between the first cylinder and the second cylinder;

or the magnetic stirring plate is vertical to the bottom surface of the reactor.

5. The apparatus for plasma catalytic reforming of greenhouse gases as claimed in claim 1, further comprising an argon storage device, a carbon dioxide storage device and a methane storage device, wherein the argon storage device and the carbon dioxide storage device are respectively communicated with the first mass flow meter through a pipeline, the methane storage device is communicated with the second mass flow meter through a pipeline, the first mass flow meter and the second mass flow meter are respectively communicated with the gas premixing tank through a pipeline, and the gas premixing tank is communicated with the gas inlet at the top of the reactor through a pipeline.

6. The apparatus for plasma catalytic reforming of greenhouse gases as claimed in claim 1, wherein the bottom of the reactor is provided with a gas outlet, the gas outlet is sequentially communicated with a soap film flowmeter, a cold trap, a gas collection tank, a gas pump and a gas chromatograph through pipelines, and the chromatograph is connected with a computer terminal.

7. The apparatus for plasma catalytic reforming of greenhouse gases of claim 6, further comprising an oscilloscope, an air pump, a thermal infrared imager, a water pump, and an ac power supply; the infrared thermal imager is used for acquiring real-time temperature data of the reactor and transmitting the real-time temperature data to the computer terminal; the heater is used for heating the circulating oil outside the reactor, the water pump is used for enabling the circulating oil to reach a circulating state, and the alternating current power supply is used for providing power for the magnetic stirrer.

8. The apparatus according to claim 1, wherein the grounded outer electrode is a stainless steel mesh covering the outer surface of the second cylinder, and the stainless steel mesh is grounded through a capacitor.

9. The apparatus for plasma catalytic reforming of greenhouse gases of claim 1, wherein the catalyst is Ni-Al₂O₃Catalyst, and the Ni-Al₂O₃The catalyst is fixed by quartz cotton.

10. A method for operating an apparatus for plasma catalytic reforming of greenhouse gases, characterized in that with an apparatus for plasma catalytic reforming of greenhouse gases according to any of claims 1-9, the method comprises the following steps:

the pulse power supply is switched on, and the electromagnetic assembly is electrified;

before the greenhouse gas is catalytically reformed by the plasma, introducing argon into a gap between a first cylinder and a second cylinder of the reactor, and reducing the catalyst in argon discharge plasma;

methane gas and carbon dioxide gas in a preset proportion are introduced into a gap between a first cylinder and a second cylinder of the reactor, and discharge is carried out under the action of an inner electrode;

the motion of the stirring plate generates a magnetic field, the original motion path of the charged particles is changed under the action of the magnetic field, and the residence time of the charged particles in the discharge interval is prolonged.

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