CN110124482A - The method of reaction of low temperature plasma device and decomposing hydrogen sulfide - Google Patents

Abstract

The invention relates to the field of plasma chemistry, and discloses a low-temperature plasma reactor and a method for decomposing hydrogen sulfide. The reactor comprises: an inner cylinder (1); an outer cylinder (2), and the outer cylinder (2) is nested in the The exterior of the inner cylinder (1); a center electrode (3), which is arranged in the inner cylinder (1); formed of a solid conductive material and forming at least part of the side wall of the inner cylinder or surrounding the inner cylinder A ground electrode (4) on the outer sidewall of the inner cylinder; forming at least part of the sidewall of the inner cylinder or surrounding a barrier medium disposed on the inner sidewall of the inner cylinder. The low-temperature plasma reactor provided by the invention can realize the continuous and stable progress of the hydrogen sulfide decomposition process under the obviously higher hydrogen sulfide conversion rate, and the device can realize long-term operation.

Description

Low temperature plasma reactor and method for decomposing hydrogen sulfide

technical field

The invention relates to the field of plasma chemistry, in particular to a low-temperature plasma reactor and a method for decomposing hydrogen sulfide.

Background technique

Hydrogen sulfide (H ₂ S) is a highly toxic and foul-smelling acid gas, which not only causes corrosion of metals and other materials, but also endangers human health and pollutes the environment. At present, large and medium-sized refineries in China adopt the traditional Claus method to treat tail gas containing H ₂ S and recover sulfur. The method recovers only the sulfur in hydrogen sulfide, but converts the valuable hydrogen into water. From the perspective of comprehensive utilization of resources, hydrogen resources have not been effectively utilized in the traditional hydrogen sulfide recovery process. Therefore, the decomposition of hydrogen sulfide into sulfur and hydrogen has gradually become a technical field that researchers at home and abroad pay close attention to.

At present, hydrogen sulfide decomposition methods mainly include: pyrolysis method, electrochemical method, photocatalytic method and low temperature plasma method. Among the aforementioned methods, the high-temperature pyrolysis method is relatively mature in industrial technology, but the thermal decomposition of hydrogen sulfide strongly depends on the reaction temperature and is limited by thermodynamic equilibrium. Only 20%. In addition, high temperature conditions have higher requirements on reactor materials, which will also increase operating costs. In addition, due to the low thermal decomposition conversion rate of hydrogen sulfide, a large amount of hydrogen sulfide gas needs to be separated from the tail gas and circulated in the system, which also reduces the efficiency of the device and increases energy consumption, which brings difficulties to its large-scale industrial application . Although the use of membrane technology can effectively separate products to break the equilibrium limit and increase the conversion rate of hydrogen sulfide, the thermal decomposition temperature often exceeds the limit heat-resistant temperature of the membrane, which damages the structure of the membrane material. The electrochemical method has disadvantages such as many operation steps, serious equipment corrosion, poor reaction stability and low efficiency. The photocatalytic decomposition of hydrogen sulfide mainly draws on the research of photocatalytic water splitting, and the research focuses on the development of high-efficiency semiconductor photocatalysts. Using solar energy to decompose hydrogen sulfide has the advantages of low energy consumption, mild reaction conditions, and simple operation, and is a relatively economical method. However, this method has problems such as small processing capacity, low catalytic efficiency and easy deactivation of the catalyst.

Compared with other decomposition methods, the low-temperature plasma method has the advantages of simple operation, small device volume, high energy efficiency, etc., and the reactions involved in it are highly controllable, and can be flexibly processed in the case of small processing volume and difficulty in centralized processing. application. In addition, due to its high energy density and shortened reaction time, it can effectively decompose hydrogen sulfide at a lower temperature, and is suitable for occasions with different scales, scattered layouts, and variable production conditions. Moreover, while recovering sulfur, the low-temperature plasma method recovers hydrogen resources, which can realize the utilization of hydrogen sulfide resources.

At present, researchers at home and abroad have conducted extensive research on the technology of low-temperature plasma decomposition of hydrogen sulfide. The discharge forms used mainly include glow discharge, corona discharge, sliding arc discharge, microwave plasma, radio frequency plasma and dielectric barrier discharge. .

Document "International journal of hydrogen energy", 2012, 37: 1335-1347. Decompose hydrogen sulfide by shrinking normal glow discharge method. Under the conditions of pressure 0.02Mpa and temperature 2000-4000K, the minimum energy consumption of hydrogen sulfide decomposition is 2.35eV/ _H2S . However, the reaction temperature is high, the pressure is low, and the harsh conditions are not easy to realize.

The document "International journal of hydrogen energy", 2012, 37: 10010-10019 uses microwave plasma to decompose hydrogen sulfide. Under the conditions of atmospheric pressure and temperature 2400K, hydrogen sulfide can be completely decomposed, but the decomposed hydrogen and sulfur will be rapidly decomposed at high temperature. Compounding regenerates hydrogen sulfide, and there is no corresponding quenching measure at present.

Document "Chemical Engineering Science", 2009, 64(23): 4826-4834. Using pulsed corona discharge to carry out the research on H ₂ S decomposition to produce hydrogen and sulfur. The reactor adopts a line-tube structure. The effects of pulse forming capacitance, discharge voltage and pulse frequency on H ₂ S conversion rate and decomposition energy efficiency were investigated. The results show that under the condition of constant power, low pulse forming capacitance, low discharge voltage and high pulse frequency are beneficial to obtain high H ₂ S decomposition energy efficiency; in addition, compared with Ar and N ₂ as balance gas, Ar-N ₂ When the gas is used as the balance gas, a higher H ₂ S conversion rate can be obtained. When the volume fraction of Ar/N ₂ /H ₂ S is 46%/46%/8%, the discharge power is 60W, and the pulse forming capacitance is 720pF, the obtained H The lowest decomposition energy consumption of ₂ S is 4.9eV/H ₂ S, but the conversion rate of H ₂ S is only about 30%. In addition, the flow rate of this reaction system is only 1.18×10 ^-4 SCMs ^-1 , and the reaction effect of low flow rate, low concentration and low conversion rate has no practical significance in industrial production.

The literature "Journal of applied physics", 1998, 84(3): 1215-1221 used sliding arc discharge to study the decomposition reaction of H ₂ S. The method was to dilute H ₂ S with air to a concentration of 0-100ppm. The effects of gas flow rate, reaction chamber size and frequency on the H ₂ S decomposition reaction were investigated under the condition that the total gas flow rate was 0-100L/min. The experimental results show that low gas flow rate, small disc spacing and low frequency are beneficial to obtain a higher H ₂ S conversion rate. Under optimized discharge conditions, the H ₂ S conversion rate can reach 75-80%, but the H ₂ S decomposition energy The consumption is as high as 500eV/H ₂ S, and the reaction effect of low concentration and high energy consumption also has no industrial application prospect.

Dielectric barrier discharge can usually be generated under atmospheric pressure, and the discharge temperature is relatively low. In addition, due to the existence of the medium, the growth of the discharge current is limited, thereby avoiding the complete breakdown of the gas to form sparks or arcs, which is conducive to the generation of large-volume and stable plasma, and has a good industrial application prospect.

The literature "Plasma chemistry and plasma processing", 1992, 12(3): 275-285 used an improved ozone generator to investigate the discharge characteristics of H ₂ S in the range of 130-560°C, and studied the reaction temperature, H ₂ S The influence of feed concentration, injection power and addition of H ₂ , Ar, N ₂ etc. on H ₂ S conversion rate and energy efficiency, the experiment found that the addition of Ar can promote the decomposition of H ₂ S, at a total flow rate of 50-100mL/min, H When the ₂ S concentration is 20-100%, the conversion rate is 0.5-12%, and the minimum hydrogen production energy consumption is about 0.75mol/kWh (50eV/H ₂ ), however, this process still has low conversion rate and high energy consumption Shortcomings.

CN102408095A uses dielectric barrier discharge and photocatalyst to decompose hydrogen sulfide synergistically. The method is to fill the plasma region with a solid catalyst with photocatalytic activity. However, this method has the disadvantage that sulfur generated by hydrogen sulfide decomposition will be deposited under the catalyst bed.

Document "International Journal of Energy Research", 2013, 37(11): 1280-1286. Al ₂ O ₃ , MoO _x /Al ₂ O ₃ , CoOx/Al ₂ O ₃ and NiO/Al ₂ O ₃ catalysts are filled in Discharge area, H ₂ S decomposition was studied using dielectric barrier discharge and catalyst. The reaction results show that the MoOx/Al ₂ O ₃ and CoOx/Al ₂ O ₃ catalysts have better effects; when the MoOx/Al ₂ O ₃ catalyst is filled, the H ₂ S/Ar total flow rate is 150mL/min, and the H ₂ S concentration is When the injection ratio is 5% by volume, the injection specific energy SIE is 0.92kJ/L, and the catalyst filling length is 10% of the bed layer, the maximum conversion rate of H ₂ S obtained is about 48%. However, the concentration of hydrogen sulfide in this reaction process is low, and the sulfur produced by decomposition is deposited inside the reactor. As time goes on, the activity of the catalyst decreases and the discharge stability decreases, resulting in a gradual decrease in the conversion rate of hydrogen sulfide.

CN103204466A discloses a temperature-controlled hydrogen sulfide decomposition device and method, the device is characterized in that the central electrode is a metal, the ground electrode is a temperature-controllable circulating liquid, through the temperature control of the liquid ground electrode, the hydrogen sulfide decomposition process can be continuous steady progress. In addition, CN103204467A discloses a device and method for continuously and stably decomposing hydrogen sulfide to produce hydrogen. The feature of this prior art is that the center electrode is a metal and the ground electrode is a temperature-controllable circulating liquid, and the temperature is controlled by the liquid ground electrode. , the raw material intake direction is circumferential intake, and passes through the discharge area reversely along the axial direction in a spiral mode, so that the generated sulfur is centrifugally separated in time. However, in the methods disclosed by CN103204466A and CN103204467A, in order to ensure that hydrogen sulfide is decomposed as fully as possible, it is necessary to control the flow rate of hydrogen sulfide so that its residence time in the inner cylinder of the reactor is longer and to control the size of the inner cylinder so that the unit volume of hydrogen sulfide in the inner cylinder is The electric energy obtained by the gas is more, and, because the current prior art cannot provide a power source with greater power, the method disclosed in CN103204466A and CN103204467A is adopted even if the residence time of hydrogen sulfide is controlled longer and the size of the inner cylinder is controlled so that the inner cylinder The more electric energy obtained by the unit volume of gas in the cylinder can only make the highest conversion rate of hydrogen sulfide reach about 20%, and when the highest conversion rate of hydrogen sulfide reaches about 20%, the energy consumption of hydrogen sulfide decomposition reaction is quite high. Not suitable for large industrial applications. Furthermore, the methods disclosed in CN103204466A and CN103204467A also have the defect that there are very few types of liquid grounding electrodes available, and the salt solutions disclosed therein can only maintain the temperature of the reactor below 100°C, and below 100°C, the simple substance Sulfur is generally solid and can easily cause blockage of the reactor.

Contents of the invention

The purpose of the present invention is to overcome the defects of low hydrogen sulfide conversion rate and high decomposition energy consumption in the low-temperature plasma reactor provided by the prior art when it is used for the decomposition of hydrogen sulfide, and provide a new method that can improve the conversion rate of hydrogen sulfide As well as a low-temperature plasma reactor for reducing decomposition energy consumption and a method for decomposing hydrogen sulfide using the reactor.

In order to achieve the above object, in a first aspect, the present invention provides a low-temperature plasma reactor, the reactor has a coaxial jacket structure, and the reactor includes:

an inner cylinder, the inner cylinder is respectively provided with a reactor inlet and a product outlet;

An outer cylinder, the outer cylinder is nested outside the inner cylinder, and the outer cylinder is respectively provided with a heat transfer medium inlet and a heat transfer medium outlet;

a central electrode, the central electrode is disposed in the inner cylinder;

A ground electrode, the material forming the ground electrode is a solid conductive material, the ground electrode forms at least part of the side wall of the inner cylinder or the ground electrode is arranged around the outer side wall of the inner cylinder; and

a barrier medium that forms at least part of the side wall of the inner cylinder or that is disposed circumferentially on the inner side wall of the inner cylinder, and the barrier medium is disposed between the center electrode and the ground electrode , and the blocking medium is positioned such that the discharge area between the center electrode and the ground electrode is separated by the blocking medium;

Wherein, the proportional relationship between the distance L ₁ between the outer wall of the central electrode and the inner wall of the barrier medium and the thickness D ₁ of the barrier medium is: L ₁ : D ₁ =(0.05˜100) :1.

In a second aspect, the present invention provides a method for decomposing hydrogen sulfide, the method is implemented in the low-temperature plasma reactor described in the first aspect of the present invention, the method includes: under dielectric barrier discharge conditions, the hydrogen sulfide containing The raw material gas is introduced into the inner cylinder of the low-temperature plasma reactor from the reactor inlet to carry out the decomposition reaction of hydrogen sulfide, and the stream obtained after the decomposition is drawn out from the product outlet, and is passed continuously from the heat-conducting medium inlet to the low-temperature plasma The heat conduction medium is introduced into the outer cylinder of the bulk reactor and the heat conduction medium is drawn out from the heat conduction medium outlet to maintain the temperature required by the low temperature plasma reactor; the dielectric barrier discharge is formed by a ground electrode, a barrier medium and a center electrode.

The aforementioned low-temperature plasma reactor provided by the present invention can be used for the plasma decomposition of hydrogen sulfide, and the reactor can generate uniform and efficient dielectric barrier discharge, thereby directly decomposing hydrogen sulfide to generate hydrogen and sulfur.

The aforementioned low-temperature plasma reactor provided by the present invention is a jacketed dielectric barrier discharge reactor with a coaxial structure, and its basic structure mainly includes a central electrode, a solid ground electrode, and a barrier medium. The discharge reactor is cyclically heated or cooled, allowing flexible temperature control of the discharge area. In particular, the present invention controls the proportional relationship between the distance L ₁ between the outer wall of the center electrode and the inner wall of the ground electrode and the thickness D ₁ of the barrier medium: L ₁ : D ₁ =(0.05-100): 1. When using a solid ground electrode, it can significantly increase the conversion rate of hydrogen sulfide and reduce the energy consumption of decomposition compared with the prior art.

In addition, the low-temperature plasma reactor provided by the present invention can realize continuous and stable hydrogen sulfide decomposition process at a significantly higher conversion rate of hydrogen sulfide, and the device can realize long-term operation. And, the low-temperature plasma reactor provided by the present invention can also be used in a large-flow, high-concentration hydrogen sulfide treatment process.

Description of drawings

Fig. 1 is a schematic structural view of a preferred embodiment of the low-temperature plasma reactor provided by the present invention.

Explanation of reference signs

1. Inner cylinder 2. Outer cylinder

11. Reactor inlet 21. Heat transfer medium inlet

12. Gas product outlet 22. Heat transfer medium outlet

13. Liquid product export

3. Center electrode

4. Grounding electrode

5. Ground wire

Detailed ways

Neither the endpoints nor any values of the ranges disclosed herein are limited to such precise ranges or values, and these ranges or values are understood to include values approaching these ranges or values. For numerical ranges, between the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, these values Ranges should be considered as specifically disclosed herein.

As mentioned above, the first aspect of the present invention provides a low-temperature plasma reactor, the reactor has a coaxial jacket structure, and the reactor includes:

an inner cylinder, the inner cylinder is respectively provided with a reactor inlet and a product outlet;

An outer cylinder, the outer cylinder is nested outside the inner cylinder, and the outer cylinder is respectively provided with a heat transfer medium inlet and a heat transfer medium outlet;

a central electrode, the central electrode is disposed in the inner cylinder;

A ground electrode, the material forming the ground electrode is a solid conductive material, the ground electrode forms at least part of the side wall of the inner cylinder or the ground electrode is arranged around the outer side wall of the inner cylinder; and

a barrier medium that forms at least part of the side wall of the inner cylinder or that is disposed circumferentially on the inner side wall of the inner cylinder, and the barrier medium is disposed between the center electrode and the ground electrode , and the blocking medium is positioned such that the discharge area between the center electrode and the ground electrode is separated by the blocking medium;

Wherein, the proportional relationship between the distance L ₁ between the outer wall of the central electrode and the inner wall of the barrier medium and the thickness D ₁ of the barrier medium is: L ₁ : D ₁ =(0.05˜100) :1.

The difference between "side wall" and "outer side wall" and "inner side wall" in the present invention is: "outer side wall" and "inner side wall" respectively represent the outer surface and inner surface of the "side wall".

Preferably, L ₁ :D ₁ =(0.1-30):1.

The design of the jacket structure of the present invention can make the heat-conducting medium circulate in the shell, maintain the entire reactor within a certain temperature range while ensuring the discharge intensity, and make the generated sulfur flow out of the reactor in liquid form, which can Effectively avoid the solidification of sulfur generated by the decomposition of hydrogen sulfide, and make the decomposition process continuous and stable for long-term operation while achieving a high conversion rate.

According to a preferred specific implementation manner, the ground electrode is arranged around the outer side wall of the inner cylinder, and the barrier medium forms at least part of the side wall of the inner cylinder.

Preferably, the material forming the barrier medium is an electrical insulating material. More preferably, the material forming the barrier medium is at least one selected from glass, ceramics, enamel, polytetrafluoroethylene and mica. The glass can be quartz glass or hard glass; the material forming the barrier medium can also be other metal and non-metal composite materials with high voltage electrical insulation design. The ceramics may be alumina ceramics.

Preferably, the reactor further includes a grounding wire, the grounding wire is arranged on the outer wall of the outer cylinder, and one end thereof is connected to the grounding electrode.

Preferably, the reactor inlet is arranged at the upper part of the inner cylinder, and the product outlet is arranged at the lower part and/or bottom of the inner cylinder.

According to a preferred specific embodiment, the product outlet includes a gas product outlet and a liquid product outlet, and the gas product outlet is arranged at the lower part of the inner cylinder, and the liquid product outlet is arranged at the bottom of the inner cylinder bottom.

In the present invention, the ratio of the inner diameter of the inner cylinder to the pore diameter of the product outlet may be (0.1˜100):1.

In the present invention, the ratio of the pore diameter of the reactor inlet to the pore diameter of the product outlet may be (0.1˜120):1.

In the present invention, the ratio between the length of the inner cylinder and the inner diameter of the inner cylinder may be (0.5˜500):1.

Preferably, the gas product outlet is arranged below the discharge area, and the ratio between the height H1 _of the position of the gas product outlet relative to the bottom of the inner cylinder and the length _L2 of the discharge area is The relationship is: H ₁ : L ₂ =1: (0.05-25000); more preferably H ₁ : L ₂ =1: (0.1-10000); more preferably H ₁ : L ₂ =1: (0.5-1000) . Preferably, the heat-conducting medium inlet and the heat-conducting medium outlet are respectively arranged at the lower part and the upper part of the outer cylinder.

In the present invention, the inner diameter ratio between the inner cylinder and the outer cylinder is not particularly limited, the inner cylinder is mainly used for hydrogen sulfide decomposition reaction, and the outer cylinder is mainly used for the decomposition reaction in the inner cylinder The required temperature is provided, and therefore, those skilled in the art can adjust and select an appropriate inner diameter ratio between the inner cylinder and the outer cylinder according to the application.

The reactor inlet of the present invention can be arranged so that the raw material gas entering the inner cylinder is parallel to the inner diameter of the inner cylinder or at a certain angle, for example, it can be arranged tangentially.

The inner diameters in the present invention all represent diameters.

Preferably, the material forming the ground electrode is selected from graphite tube, metal tube, metal foil or metal mesh. The solid ground electrode of the present invention cooperates with the structure of the low-temperature plasma reactor of the present invention, and the micro-discharge current generated under the condition of constant injection power is larger, which is more conducive to the bond breaking and decomposition reaction of hydrogen sulfide. The metal tube and metal foil in the material forming the ground electrode may include simple metal tube, simple metal foil, alloy metal tube, and alloy metal foil. The inventors of the present invention have found that when a solid conductive material is used as the ground electrode to surround the outer wall of the inner cylinder, the conversion of hydrogen sulfide can be achieved when the low-temperature plasma reactor provided by the present invention is used for hydrogen sulfide decomposition rate increased significantly.

Preferably, the ground electrode of the present invention has conductivity and can be wrapped on the surface of the barrier medium.

The material forming the central electrode is a conductive material. Preferably, the material forming the central electrode is selected from at least one of graphite tubes, metal rods, metal tubes and graphite rods. The metal rods and metal tubes may include simple metal rods, alloy metal rods, simple metal tubes, and alloy metal tubes. The material forming the center electrode of the present invention may be other rod-shaped and tubular materials with conductive properties.

The present invention can maintain the temperature of the reactor with a jacket structure at, for example, 119-444.6°C by introducing a heat-conducting medium into the area between the outer wall of the inner cylinder and the inner wall of the outer cylinder to ensure The sulfur produced by the decomposition of hydrogen sulfide flows out of the discharge area in liquid form.

The low-temperature plasma reactor of the present invention may also be filled with a catalyst capable of catalyzing the decomposition of hydrogen sulfide into elemental sulfur and hydrogen, and the catalyst is preferably loaded in the inner cylinder of the reactor. The present invention has no special requirements on the loading volume and loading type of the catalyst, and the type of the catalyst may be any one or more of the catalysts disclosed in CN102408095A, CN101590410A and CN103495427A, for example.

As mentioned above, the second aspect of the present invention provides a method for decomposing hydrogen sulfide, the method is implemented in the low-temperature plasma reactor described in the first aspect, the method includes: under dielectric barrier discharge conditions, the The feed gas containing hydrogen sulfide is introduced into the inner cylinder of the low-temperature plasma reactor from the reactor inlet to carry out the decomposition reaction of hydrogen sulfide. The outer cylinder of the low-temperature plasma reactor is introduced with a heat-conducting medium and the heat-conducting medium is drawn out from the outlet of the heat-conducting medium to maintain the temperature required by the low-temperature plasma reactor. The dielectric barrier discharge is formed by the ground electrode, the barrier medium and the center electrode formation.

The low-temperature plasma reactor provided by the present invention has no special limitation on the conditions of the decomposition reaction involved in the decomposition of hydrogen sulfide, and can be carried out under the various conditions involved in the plasma decomposition hydrogen sulfide method conventionally used in the art Decomposition, the embodiment of the present invention exemplifies the conditions for decomposing hydrogen sulfide, which should not be understood by those skilled in the art as a limitation of the present invention.

In the present invention, there is no particular limitation on the material forming the outer cylinder, as long as the material forming the outer cylinder can withstand the set temperature of the heat transfer medium.

The low-temperature plasma reactor provided by the present invention has no special limitation on the concentration of hydrogen sulfide in the gas at the reactor inlet, for example, the concentration of hydrogen sulfide in the gas may be 0.01-100% by volume.

The structure of a preferred embodiment of the low temperature plasma reactor of the present invention is provided below in conjunction with Fig. 1, specifically:

The reactor has a coaxial jacketed sleeve structure, and the reactor includes:

An inner cylinder 1, the inner cylinder 1 is respectively provided with a reactor inlet 11 and a product outlet;

An outer cylinder 2, the outer cylinder 2 is nested outside the inner cylinder 1, and the outer cylinder 2 is respectively provided with a heat transfer medium inlet 21 and a heat transfer medium outlet 22;

a central electrode 3, the central electrode 3 is arranged in the inner cylinder 1;

A ground electrode 4, the material forming the ground electrode 4 is a solid conductive material, the ground electrode 4 forms at least part of the side wall of the inner cylinder 1 or the ground electrode 4 is arranged around the outer wall of the inner cylinder 1; as well as

A barrier medium, the barrier medium forms at least part of the side wall of the inner cylinder 1 or the barrier medium is arranged around the inner side wall of the inner cylinder 1, and the barrier medium is arranged on the center electrode 3 and the ground Between the electrodes 4, and the blocking medium is positioned so that the discharge area between the central electrode and the ground electrode is separated by the blocking medium;

Wherein, the proportional relationship between the distance L ₁ between the outer wall of the central electrode 3 and the inner wall of the barrier medium and the thickness D ₁ of the barrier medium is: L ₁ : D ₁ =(0.05-100 ):1; preferably L ₁ :D ₁ =(0.1-30):1.

In the present invention, preferably, the ground electrode 4 is arranged around the outer wall of the inner cylinder 1 , and the barrier medium forms at least part of the side wall of the inner cylinder 1 .

Preferably, the reactor further includes a grounding wire 5 , the grounding wire 5 is arranged on the outer wall of the outer cylinder 2 , and one end thereof is connected to the grounding electrode 4 .

Preferably, the reactor inlet 11 is arranged at the upper part of the inner cylinder 1 , and the product outlet is arranged at the lower part and/or bottom of the inner cylinder 1 .

Preferably, the product outlet includes a gas product outlet 12 and a liquid product outlet 13, and the gas product outlet 12 is arranged at the lower part of the inner cylinder 1, and the liquid product outlet 13 is arranged at the inner cylinder 1 bottom of.

Preferably, the gas product outlet 12 is arranged below the discharge area, and the location of the gas product outlet ₁₂ is between the height H1 of the bottom of the inner cylinder ₁ and the length L2 of the discharge area. The proportional relationship among them is: H ₁ : L ₂ =1: (0.05～25000); more preferably H ₁ : L ₂ =1: (0.1～10000); more preferably H ₁ : L ₂ =1: (0.5 ~1000).

Preferably, the heat-conducting medium inlet 21 and the heat-conducting medium outlet 22 are respectively arranged at the lower part and the upper part of the outer cylinder 2 .

Another preferred embodiment of applying the aforementioned low-temperature plasma reactor of the present invention to decompose hydrogen sulfide is provided below:

Nitrogen gas is introduced into the inner cylinder of the low-temperature plasma reactor from the reactor inlet to remove the air in the discharge area, and the gas is drawn out from the product outlet. At the same time, the heat transfer medium is introduced into the outer cylinder from the heat transfer medium inlet, and the introduced heat transfer medium is led out from the heat transfer medium outlet. The temperature of the heat transfer medium is maintained at the temperature required by the system reaction. Then feed the raw material gas containing hydrogen sulfide into the inner cylinder of the low-temperature plasma reactor from the inlet of the reactor, and turn on the high-voltage power supply after the raw material gas flow is stable, and form a plasma discharge between the center electrode and the ground electrode by adjusting the voltage and frequency field. The hydrogen sulfide gas is ionized in the discharge area and decomposed into hydrogen and elemental sulfur. The elemental sulfur produced by the discharge slowly flows down the inner cylinder wall and flows out from the product outlet.

The low temperature plasma reactor provided by the invention also has the following specific advantages:

(1) The reactor uses a conductive solid material as the grounding electrode. Compared with the liquid grounding electrode, the micro-discharge current generated by the discharge when this grounding electrode cooperates with the structure of the present invention is larger, which is more conducive to the discharge decomposition reaction of hydrogen sulfide molecules .

(2) A jacket structure is set outside the ground electrode of the reactor, and the temperature of the reactor can be controlled by controlling the temperature of the heat-conducting medium in the jacket, so that the sulfur generated by the hydrogen sulfide discharge decomposition can flow out of the discharge area smoothly, and the sulfur solidification can be avoided to block the reaction device, so that the discharge continues and stably proceeds.

(3) The proportional relationship between the distance L ₁ between the outer wall of the center electrode and the inner wall of the ground electrode and the thickness D ₁ of the barrier medium in the reactor is: L ₁ : D ₁ =( 0.05-100): 1, preferably L ₁ : D ₁ = (0.1-30): 1, combined with other structures of the reactor of the present invention, can significantly increase the conversion rate of hydrogen sulfide and reduce energy consumption for decomposition.

The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, all raw materials used are commercially available.

The thickness of the barrier medium in the following examples and comparative examples is the same.

The conversion ratio of hydrogen sulfide in the following examples is calculated according to the following formula:

The conversion rate of hydrogen sulfide% = the number of moles of converted hydrogen sulfide / the number of moles of initial hydrogen sulfide × 100%

In the following example, the energy consumption for decomposing hydrogen sulfide is obtained through oscilloscope detection and Lissajous graph calculation.

Example 1

The low-temperature plasma reactor shown in Figure 1 is used to carry out hydrogen sulfide decomposition reaction. The specific structure and structural parameters of the low-temperature plasma reactor are as follows:

The reactor includes:

An inner cylinder, the inner cylinder is respectively provided with a reactor inlet, a gas product outlet and a liquid product outlet, wherein all side walls of the inner cylinder are formed by a barrier medium, and the material forming the barrier medium is hard glass ;

An outer cylinder, the outer cylinder is nested outside the inner cylinder, and the outer cylinder is respectively provided with a heat transfer medium inlet and a heat transfer medium outlet;

A central electrode, the central electrode is arranged at the central axis of the inner cylinder, and the material forming the central electrode is a stainless steel metal rod;

A ground electrode, the ground electrode is wrapped on the outer side wall of the inner cylinder, the material forming the ground electrode is stainless steel metal foil, and the lower edge of the center electrode in this embodiment is shorter than the lower edge of the ground electrode Low;

The ratio of the distance L1 between the outer sidewall of the center electrode and the inner sidewall _of the barrier medium to the thickness D1 of the barrier medium is 6: ₁ ;

_The proportional relationship between the height H1 _of the location of the gas product outlet relative to the bottom of the inner cylinder and the length L2 of the discharge area containing the barrier medium is: H1:L2 ₌ 1:46 _;

The volume of the inner cylinder of the reactor in this embodiment is 0.2L.

In this embodiment, the mixed gas enters the reactor inner cylinder from the upper part of the reactor inner cylinder, and the gas product is drawn out from the gas product outlet located at the lower part of the reactor inner cylinder, and the elemental sulfur is drawn out from the liquid product outlet located at the bottom of the reactor; and this The heat transfer medium of the embodiment is introduced from the lower part of the outer cylinder of the reactor, and drawn out from the upper part of the outer cylinder of the reactor.

Operation steps of low temperature plasma reactor:

Nitrogen gas is introduced into the inner barrel of the low-temperature plasma reactor from the reactor inlet to remove the air in the discharge area, and the gas is drawn out from the gas product outlet and the liquid product outlet. At the same time, a heat transfer medium (specifically simethicone oil) is introduced into the outer cylinder from the heat transfer medium inlet, and the introduced heat transfer medium is led out from the heat transfer medium outlet, and the temperature of the heat transfer medium is kept at 145°C.

Then pass H2S/Ar mixed gas from the inlet of the reactor into the inner cylinder of the low _- temperature plasma reactor, wherein the volume fraction of H2S is ₂₀ %, and the flow rate of the mixed gas is controlled so that the average residence time of the gas in the discharge area is 9.5s . After the H ₂ S/Ar mixture gas was passed into the reactor for 30 minutes, the AC high-voltage power supply was switched on, and a plasma discharge field was formed between the center electrode and the ground electrode by adjusting the voltage and frequency. The discharge conditions are as follows: the voltage is 16.8kV, the frequency is 7.5kHz, and the current is 0.75A. The hydrogen sulfide gas is ionized in the discharge area and decomposed into hydrogen and elemental sulfur. The elemental sulfur produced by the discharge slowly flows down the inner cylinder wall, and the liquid product is released intermittently. After the reaction, the gas flows out from the gas product outlet.

Results: After the hydrogen sulfide decomposition reaction in this example continued for 20 minutes, the conversion rate of H ₂ S was measured to be 73.9%; and no abnormality was found after continuous discharge for 100 hours, and the discharge state and conversion rate of H ₂ S remained stable. In addition, the decomposition energy consumption in this embodiment is 13eV/H ₂ S molecule (the energy required to decompose 1 molecule of H ₂ S is 13eV).

Comparative example 1

This comparative example adopts the low temperature plasma reactor similar to embodiment 1 to carry out hydrogen sulfide decomposition reaction, difference is:

The grounding electrode in this comparative example is a liquid grounding electrode, and it is LiCl and AlCl ₃ in a molten state with a molar ratio of 1:1. The liquid grounding electrode is also a heat-conducting medium, and the temperature is kept at 145°C, and it is placed in the outer cylinder of the reactor. .

The flow rate of the mixed gas is controlled so that the average residence time of the gas in the discharge area is 18.5s.

The reactor inner cylinder of this comparative example has a volume of 0.05L.

All the other are the same as in Example 1.

And this comparative example adopts the same operation method as Example 1 to carry out the hydrogen sulfide decomposition reaction.

Results: The hydrogen sulfide decomposition reaction in this comparative example was continuously carried out for 20 minutes, and the conversion rate of H ₂ S was measured to be 15.6%, and the conversion rate of H ₂ S decreased to 5.1% after continuous discharge for 1.5 hours.

The decomposition energy consumption of this comparative example is 102eV/H ₂ S molecule.

Comparative example 2

This comparative example adopts the low-temperature plasma reactor similar to Comparative Example 1 to carry out, the difference is:

In this comparative example, the ratio of the distance L ₁ between the outer wall of the central electrode and the inner wall of the barrier medium to the thickness D ₁ of the barrier medium is 0.01:1.

Control the flow rate of the mixed gas so that the average residence time of the gas in the discharge area is 18.5s;

The volume of the inner cylinder of this comparative example is 0.02L.

The rest are the same as in Comparative Example 1.

Results: The hydrogen sulfide decomposition reaction in this comparative example was continuously carried out for 20 minutes, and the conversion rate of H ₂ S was measured to be 20.8%, and the conversion rate of H ₂ S decreased to 5.3% after continuous discharge for 1.5 hours.

The decomposition energy consumption of this comparative example is 137eV/H ₂ S molecule.

Example 2

The present embodiment adopts the plasma reactor similar to embodiment 1 to carry out the decomposition reaction of hydrogen sulfide, the difference is, in the present embodiment:

All side walls of the inner cylinder are formed by grounding electrodes, and the material for forming the grounding electrodes is stainless steel metal foil;

The blocking medium is arranged around the inner wall of the inner cylinder;

The ratio of the distance L1 between the outer sidewall of the central electrode and the inner sidewall _of the barrier medium to the thickness D1 of the barrier medium is 20: ₁ ;

The proportional relationship between H ₁ and the length L ₂ of the discharge region containing the blocking medium is: H ₁ : L ₂ =1:100.

In this example, H ₂ S/Ar mixed gas is introduced into the inner cylinder of the low-temperature plasma reactor from the inlet of the reactor, wherein the volume fraction of H ₂ S is 30%, and the flow rate of the mixed gas is controlled so that the average residence time of the gas in the discharge area is It is 7.8s. After the H ₂ S/Ar mixture gas was passed into the reactor for 30 minutes, the AC high-voltage power supply was switched on, and a plasma discharge field was formed between the center electrode and the ground electrode by adjusting the voltage and frequency. The discharge conditions are as follows: the voltage is 19.8kV, the frequency is 10.5kHz, and the current is 1.25A.

All the other are the same as in Example 1.

Results: After the hydrogen sulfide decomposition reaction in this example continued for 20 minutes, the conversion rate of H ₂ S was measured to be 72.8%; and no abnormality was found after continuous discharge for 100 hours, and the discharge state and conversion rate of H ₂ S remained stable. And the decomposition energy consumption in this embodiment is 14.2eV/H ₂ S molecule.

Example 3

The present embodiment adopts the plasma reactor similar to embodiment 1 to carry out the decomposition reaction of hydrogen sulfide, the difference is, in the present embodiment:

All side walls of the inner cylinder are formed by ground electrodes, and the material for forming the ground electrodes is copper foil;

The blocking medium is arranged around the inner wall of the inner cylinder;

The ratio of the distance L1 between the outer sidewall of the central electrode and the inner sidewall _of the barrier medium to the thickness D1 of the barrier medium is 0.5: ₁ ;

The proportional relationship between H ₁ and the length L ₂ of the discharge region containing the blocking medium is: H ₁ : L ₂ =1:200.

In this embodiment, H ₂ S/Ar mixed gas is introduced into the inner cylinder of the low-temperature plasma reactor from the inlet of the reactor, wherein the volume fraction of H ₂ S is 25%, and the flow rate of the mixed gas is controlled so that the average residence time of the gas in the discharge area is It is 10.3s. After the H ₂ S/Ar mixture gas was passed into the reactor for 30 minutes, the AC high-voltage power supply was switched on, and a plasma discharge field was formed between the center electrode and the ground electrode by adjusting the voltage and frequency. The discharge conditions are as follows: the voltage is 12.8kV, the frequency is 4.7kHz, and the current is 1.12A.

All the other are the same as in Example 1.

Results: After the hydrogen sulfide decomposition reaction in this example continued for 20 minutes, the conversion rate of H ₂ S was measured to be 73.2%; and no abnormality was found after continuous discharge for 100 hours, and the discharge state and conversion rate of H ₂ S remained stable. And the decomposition energy consumption in this embodiment is 14.8eV/H ₂ S molecule.

Example 4

The present embodiment adopts the plasma reactor similar to embodiment 1 to carry out the decomposition reaction of hydrogen sulfide, the difference is, in the present embodiment:

The ratio of the distance L ₁ between the outer sidewall of the central electrode and the inner sidewall of the barrier medium to the thickness D ₁ of the barrier medium is 35:1.

All the other are the same as in Example 1.

Results: After the hydrogen sulfide decomposition reaction in this example continued for 20 minutes, the conversion rate of H ₂ S was measured to be 71.6%; and no abnormality was found after continuous discharge for 100 hours, and the discharge state and conversion rate of H ₂ S remained stable. And the decomposition energy consumption in this embodiment is 22.3eV/H ₂ S molecule.

As can be seen from the above results, when the low temperature plasma reactor provided by the invention is used to decompose hydrogen sulfide, the conversion rate of hydrogen sulfide can be significantly improved relative to the prior art, and the reactor provided by the invention can be used at low decomposition energy High hydrogen sulfide conversion is maintained over long periods of time.

The preferred embodiments of the present invention have been described in detail above, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the disclosed content of the present invention. All belong to the protection scope of the present invention.

Claims (12)

1. A low-temperature plasma reactor, the reactor has a coaxial jacket sleeve structure, and the reactor comprises: an inner cylinder (1), the inner cylinder (1) is respectively provided with a reactor inlet (11) and a product outlet; An outer cylinder (2), the outer cylinder (2) is nested outside the inner cylinder (1), and the outer cylinder (2) is respectively provided with a heat transfer medium inlet (21) and a heat transfer medium outlet (22 ); a central electrode (3), the central electrode (3) is arranged in the inner cylinder (1); A ground electrode (4), the material forming the ground electrode (4) is a solid conductive material, the ground electrode (4) forms at least part of the side wall of the inner cylinder (1) or the ground electrode (4) is arranged around on the outer wall of the inner cylinder (1); and A barrier medium, the barrier medium forms at least part of the side wall of the inner cylinder (1) or the barrier medium is arranged around the inner side wall of the inner cylinder (1), and the barrier medium is arranged on the center electrode ( 3) between the ground electrode (4) and the barrier medium so that the discharge area between the central electrode and the ground electrode is separated by the barrier medium; Wherein, the proportional relationship between the distance L ₁ between the outer wall of the central electrode (3) and the inner wall of the barrier medium and the thickness D ₁ of the barrier medium is: L ₁ : D ₁ =(0.05 ~100): 1. 2 . The low temperature plasma reactor according to claim 1 , wherein L ₁ :D ₁ =(0.1˜30):1. 3. The low temperature plasma reactor according to claim 1, wherein the ground electrode (4) is arranged around the outer wall of the inner cylinder (1), and the barrier medium forms the inner cylinder (1) at least part of the sidewall. 4. The low-temperature plasma reactor according to any one of claims 1-3, wherein the material forming the barrier medium is an electrical insulating material; preferably, The material forming the barrier medium is at least one selected from glass, quartz, ceramics, enamel, polytetrafluoroethylene and mica. 5. The low-temperature plasma reactor according to any one of claims 1-3, wherein the reactor further comprises a grounding wire (5), and the grounding wire is arranged on the outer wall of the outer cylinder (2) , and one end is connected to the ground electrode (4). 6. The low-temperature plasma reactor according to any one of claims 1-3, wherein the reactor inlet (11) is arranged on the top of the inner cylinder (1), and the product outlet is arranged on the The bottom and/or bottom of the inner cylinder (1). 7. The low temperature plasma reactor according to claim 6, wherein the product outlet comprises a gaseous product outlet (12) and a liquid product outlet (13), and the gaseous product outlet (12) is arranged in the inner The lower part of the barrel (1 ), and said liquid product outlet (13) are arranged at the bottom of said inner barrel (1). 8. The low-temperature plasma reactor according to claim 7, wherein the gas product outlet (12) is arranged below the discharge region, and the gas product outlet (12) is positioned relative to the The proportional relationship between the height H ₁ of the bottom of the inner cylinder (1) and the length L ₂ of the discharge area is: H ₁ : L ₂ =1: (0.05-25000); preferably H ₁ : L ₂ =1: (0.1-10000); more preferably H ₁ : L ₂ =1: (0.5-1000). 9. The low-temperature plasma reactor according to any one of claims 1-3, wherein the heat transfer medium inlet (21) and the heat transfer medium outlet (22) are respectively arranged in the outer cylinder (2) lower and upper parts. 10. The low temperature plasma reactor according to claim 1, wherein the material forming the ground electrode (4) is selected from graphite tube, metal tube, metal foil or metal mesh. 11. The low-temperature plasma reactor according to claim 1, wherein the material forming the central electrode (3) is selected from at least one of graphite tubes, metal rods, metal tubes and graphite rods. 12. A method for decomposing hydrogen sulfide, the method is implemented in the low-temperature plasma reactor described in any one of claims 1-11, the method comprises: under dielectric barrier discharge conditions, the raw material containing hydrogen sulfide The gas is introduced from the reactor inlet into the inner cylinder of the low-temperature plasma reactor to carry out the decomposition reaction of hydrogen sulfide, and the stream obtained after the decomposition is drawn out from the product outlet, and, through the continuous flow from the heat-conducting medium inlet to the low-temperature plasma The heat conduction medium is introduced into the outer cylinder of the reactor and drawn out from the heat conduction medium outlet to maintain the required temperature of the low temperature plasma reactor. The dielectric barrier discharge is formed by a ground electrode, a barrier medium and a center electrode.