Process for producing a catalyst for hydrogen sulfide electric field enhanced decomposition, decomposition method and device

Abstract

The application discloses a catalyst preparation method, a decomposition method and a device for hydrogen sulfide electric field reinforced decomposition. The catalyst is a functional composite catalyst doped with a double metal sulfide catalyst, an oxide or a carbon-based carrier and silicon carbide in proportion. The catalyst is placed in a cylindrical electrode plate to form a catalyst bed layer. The cylindrical electrode plate is connected with an anode electrode rod and then placed in a reactor. A cathode electrode rod is inserted into the catalyst bed layer. Inert gas is filled into the reactor and heated until the target temperature is reached. A mixed gas containing hydrogen sulfide with a specific concentration is filled into the reactor. An electric field is applied to the outside and center of the catalyst bed layer to form a current path. The mixed gas is decomposed under the action of the electric field to obtain a target product. The method breaks through the limitation of thermodynamic equilibrium on the reaction and efficiently promotes the decomposition process of hydrogen sulfide.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrocatalysis, in particular to a catalyst preparation method, decomposition method and device for hydrogen sulfide electric field reinforced decomposition. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] Hydrogen sulfide (H2S) gas, with high irritancy and strong acidity, is one of the main atmospheric pollutants, which not only harms human health, but also causes corrosion to equipment to varying degrees. Therefore, it is necessary to scientifically and reasonably dispose of H2S waste gas, and it is undoubtedly of great significance to realize the recovery of valuable resources by using a resourceful method.

[0004] Currently, the Claus process is widely used in industry to prepare sulfur from H2S, but neither the catalytic oxidation of H2S nor the Claus process for recovering sulfur is the optimal way for H2S resource treatment, because these methods directly change the H element in H2S into H2O, rather than H2 which has higher utilization value.

[0005] According to research, the H-S bond energy in H2S molecules is relatively weak, and the bond breaking reaction can occur at about 300℃ to generate hydrogen and sulfur, so the direct decomposition technology of H2S not only recovers sulfur, but also obtains important green energy hydrogen, thereby realizing the value-added utilization of H2S, which is an important direction for efficient resource utilization of H2S, and has become one of the research hotspots in the field of petroleum and chemical industry.

[0006] Although H2S has a relatively low bond energy between sulfur and hydrogen atoms, in fact, the decomposition of H2S is limited by thermodynamic equilibrium, so that the equilibrium conversion rate is only about 20% at 1000℃.

[0007] Molecular dynamics studies have shown that the apparent activation energy of the direct decomposition reaction of H2S is high (496 kJ / mol), and how to effectively reduce this barrier in the reaction process is a major challenge faced by H2S decomposition technology. Although the high-temperature catalytic decomposition method cannot break through the limitation of thermodynamic equilibrium, this method uses a catalyst to reduce the reaction activation energy, and achieves a higher conversion rate.

[0008] In addition, in order to break through the limitation of thermodynamics, researchers realize the efficient conversion of H2S by introducing various external energy, such as microwave thermal catalysis, which realizes the efficient decomposition of H2S by using the special heating mechanism of microwave and its non-thermal effect; or by using various new methods such as electrocatalysis, photocatalysis, low-temperature plasma, etc. But due to the above reasons, such as high equipment requirements, low H2S gas concentration, low energy efficiency, high cost, etc., these methods of direct decomposition of H2S are still in the laboratory stage, and it is still difficult to realize industrial application.

[0009] As a new type of external field strengthening method, electric field strengthening realizes reaction strengthening by exciting surface thermal electron collision with sulfur hydrogen bond through high-density energy. Electric field can synergize with catalyst to effectively reduce reaction activation energy, thereby reducing reaction difficulty; in addition, electric field strengthening technology has high concentration H2S processing capacity and great potential for industrial application. However, research has found that the efficient performance of electric field strengthening depends largely on the organic adaptation and synergy with the catalyst, so finding a catalyst that can achieve high efficiency with electric field is the focus of research.

[0010] Metal sulfides are considered to have good H2S decomposition capacity and do not introduce other impurity elements, and have superior selectivity to hydrogen. Some of the metal sulfides have semiconductor properties, and the excitation and transition process of electrons is more likely to occur, and it has been reported that double metal sulfides have better catalytic performance than single metal sulfides. However, as a high-density energy strengthening method, electric field needs to develop catalysts that are suitable for electric field to ensure the stability and efficiency of electric field strengthening process. At present, there is no catalyst that meets the above use requirements, so it needs to be developed to meet the stability, durability and recyclability of the catalyst in the electric field, and more importantly, to ensure good catalytic activity to realize efficient decomposition of H2S.

[0011] In addition, the preparation method of the catalyst from simple calcination to porous carrier impregnation, hydrothermal, to complex synthesis method such as gelatinization gel, makes the catalyst have more precise structure and application targeting, and more active sites and stronger adsorption capacity. But with the gradual complexity and harshness of the preparation process, some methods have high process difficulty and preparation cost, which is difficult to face industrial application. For the catalysts adapted to the electric field strengthening method, a simple and easy-to-operate preparation method or process flow also becomes the focus of attention. SUMMARY

[0012] To solve the above problems, the application provides a hydrogen sulfide electric field reinforced decomposition catalyst preparation method, a decomposition method and a device.

[0013] To achieve the above object, the application adopts the following technical scheme:

[0014] In the first aspect, the application provides a hydrogen sulfide electric field reinforced decomposition catalyst preparation method, comprising:

[0015] The first metal element source material and the second metal element source material are mixed in a certain proportion to form a precursor mixture;

[0016] The precursor mixture and thiourea are mixed in a certain proportion, and then deionized water is added for ultrasonic magnetic stirring;

[0017] After the ultrasonic magnetic stirring is completed, sodium dodecyl sulfate is added for continued ultrasonic magnetic stirring, thereby obtaining a catalyst precursor solution;

[0018] The catalyst precursor solution is subjected to a hydrothermal reaction, the obtained liquid is vacuum filtered to obtain a precipitate, and the precipitate is washed and dried to obtain a target catalyst;

[0019] The target catalyst, silicon carbide powder, and oxide carrier powder or carbon-based carrier powder are ground to obtain a composite catalyst;

[0020] The composite catalyst is subjected to tabletting treatment, and the obtained sheet-shaped catalyst is crushed and sieved to obtain a hydrogen sulfide electric field reinforced decomposition catalyst.

[0021] As an optional implementation, the first metal element source material and the first metal element source material are mixed in a mass ratio of 1:1-3.

[0022] As an optional implementation, the precursor mixture and thiourea are mixed in a mass ratio of 1:0.5-1.

[0023] As an optional implementation, the mass ratio of deionized water to the mass of the mixture of the precursor mixture and thiourea is 140-145:1.

[0024] As an optional implementation, the mass ratio of sodium dodecyl sulfate to the second metal element source material is 1:0.9-1.

[0025] As an optional implementation, the ultrasonic magnetic stirring time ranges from 15 to 30 minutes.

[0026] As an alternative embodiment, the hydrothermal reaction is a hydrothermal reaction at 180℃ for 12-18h.

[0027] As an alternative embodiment, the ratio of the oxide carrier powder or the carbon-based carrier powder to the target catalyst is 1:0.05-0.15, and the ratio of the oxide carrier powder or the carbon-based carrier powder to the silicon carbide powder is 1:0.1-0.5.

[0028] As an alternative embodiment, the pressure range during the tabletting process is 15-24MPa; and the tabletting process duration is 5-10min.

[0029] As an alternative embodiment, the screen mesh size of the sieving is 18-40mesh.

[0030] In a second aspect, the present application provides a hydrogen sulfide electric field enhanced decomposition method, comprising:

[0031] The catalyst is placed in the cylindrical electrode plate to form a catalyst bed layer; the catalyst is prepared by the method of the first aspect;

[0032] The cylindrical electrode plate is connected with the anode electrode rod and then placed in the reactor, and the cathode electrode rod is inserted into the catalyst bed layer;

[0033] Inert gas is filled into the reactor and heated until the target temperature is reached;

[0034] The mixed gas containing a specific concentration of H2S is filled into the reactor, and an electric field is applied to the outside and center of the catalyst bed layer to form a current path, so that the mixed gas is decomposed under the action of the electric field to obtain the target product.

[0035] As an alternative embodiment, the electric field intensity ranges from 0 to 0.2kV / mm, the current of the catalyst bed layer ranges from 1 to 20mA, and the reaction temperature is set to 400-700℃.

[0036] In a third aspect, the present application provides a hydrogen sulfide electric field enhanced decomposition device, comprising: a high-temperature catalytic device and an electric field enhancement device;

[0037] The high-temperature catalytic device comprises: a reactor and a heat source supply device for heating the reactor, and a catalyst bed layer is arranged in the reactor;

[0038] The electric field enhancement device comprises: an anode electrode rod, a cathode electrode rod and a cylindrical electrode plate.

[0039] The cylindrical electrode plate is in contact with the catalyst, the anode electrode rod is inserted from the gas inlet side of the high-temperature catalytic device and connected with the cylindrical electrode plate, and one end of the cathode electrode rod is inserted into the center of the catalyst bed layer and the other end is inserted out from the gas outlet side of the high-temperature catalytic device, so that a uniform current is formed from the periphery to the center in the catalyst bed layer.

[0040] Compared with the prior art, the present application has the following advantages:

[0041] The present application provides a preparation method of a catalyst for H2S electric field enhanced decomposition, which is a double-metal sulfide catalyst, an oxide or a carbon-based carrier doped with silicon carbide at a specific ratio. On the one hand, it ensures the stability of the electric field of the catalyst bed, and on the other hand, it realizes the efficient cooperation between the electric field and the catalyst, thereby improving the ability to decompose H2S gas under the electric field enhancement mode. Metal sulfide is generally a semiconductor with good electron transition ability, thereby showing high electrical conductivity; selecting the same type of porous carrier such as alumina can regulate the electrical conductivity of the catalyst bed, change the electric field strength, and on the other hand, by virtue of its porous characteristics, a pore micro-electric field is formed to promote the play of the electric field enhancement effect; the addition of silicon carbide can provide support strength for the bed layer, and also regulate the discharge risk caused by the excessively low resistivity of the bed layer.

[0042] The electric field and the composite catalyst realize mutual cooperation to realize the enhanced catalysis of the H2S decomposition process. The composite catalyst is matched and regulated at a specific ratio, which can effectively adsorb the H2S molecules flowing through, and the directional electron movement under the electric field enhancement participates in the first step reaction of the catalyst and H2S, strengthens the oxidation-reduction progress, and accelerates the conversion process of low-sulfur to high-sulfur metal. In this process, H2S molecules release H*, which is then synthesized into H2 under the directional driving of the electric field. The high-sulfur metal is in a non-stable state under strong energy input, and finally releases S and forms S2 condensation downstream of the device. In this reaction process, the first metal maintains high catalytic performance while the transition characteristics of the second metal strengthen the ability to compete for S, so that the transformation from low-sulfur to high-sulfur metal under the action of the electric field becomes easier, which is a unique advantage of the catalyst matching the electric field effect.

[0043] The present application provides an H2S electric field enhanced decomposition method and device, which applies an electric field to the outside and center of the catalyst bed layer and forms an electric current path, thereby breaking through the limitation of thermodynamic equilibrium on the reaction. This method can form a large number of hot electrons inside the catalyst bed layer and form a regular flow state, thereby promoting the gain and loss of electrons when H2S and catalyst active substances interact, and efficiently promoting the decomposition process of H2S.

[0044] The H2S electric field reinforced decomposition method provided by the present application does not exist liquid phase or molten state electrolyte, and corresponding does not exist span transfer of some anions and cations; due to the electric field applied to the catalyst bed, the resistance of the catalyst bed is much larger than the liquid phase resistance in the electro-catalysis, the applied voltage is in the range of 0.1-2kV, and the bed current is only 1-20mA, which is one of the key elements distinguishing from the plasma method; under the relatively low voltage, after the trace current passes through the bed, the flowability decomposition of the high concentration H2S can be realized.

[0045] The advantages of the additional aspects of the present application will be partially given in the following description, partially will become obvious from the following description, or will be known by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0046] The drawings accompanying the specification of the present application serve to provide further understanding of the present application, the illustrative embodiments of the present application and the description thereof serve to explain the present application, and do not constitute improper limitation to the present application.

[0047] Figure 1 The flow chart of the catalyst preparation method for hydrogen sulfide electric field reinforced decomposition provided for the embodiment 1 of the present application;

[0048] Figure 2 The volt-ampere characteristic curve of the prepared catalyst provided for the embodiment 1 of the present application;

[0049] Figure 3 The H2S decomposition data summary graph under different electric field intensities provided for the embodiment 2 of the present application;

[0050] Figure 4 The H2S decomposition data summary graph under different temperatures provided for the embodiment 2 of the present application;

[0051] Figure 5 The H2S electric field reinforced decomposition device schematic diagram provided for the embodiment 3 of the present application;

[0052] Figures 6(a)-6(c) The electric field reinforced device schematic diagram provided for the embodiment 3 of the present application;

[0053] Wherein, 1, infrared temperature measuring device, 2, gas inlet, 3, gas outlet, 4, anode electrode rod, 5, cathode electrode rod, 6, heat source supply device, 7, reactor, 8, cylindrical electrode plate, 9, direct current high voltage power supply, 10, catalyst bed. DETAILED DESCRIPTION

[0054] The present application will be further described below in combination with the drawings and embodiments.

[0055] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. 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 application belongs.

[0056] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting, as the scope of the application will be limited only by the appended claims. Unless defined otherwise, 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 application belongs. Unless otherwise required by context, singular terms shall include pluralities and vice versa. Plural elements can be separated by a hyphenated form of the element name, for example, "multiple elements". The terms "about" and "substantially" are used herein to describe a situation in which a value is expected to be within a range of values that is acceptable for a particular application. The terms "comprises", "comprising", "includes", "including", "has", "having" and the like are used to mean inclusive rather than exclusive, that is, "comprising" and the like mean including but not limited to. The terms "first", "second", "third", "fourth", "fifth" and the like, as used herein, do not denote any order, quantity, or importance, but are used to denote one of a plurality of similar elements. The terms "front", "back", "top", "bottom", "over", "under", and the like in reference to a structure, are used only for the purpose of ease of description, and do not limit the position or orientation of the structure. The terms "coupled" and "connected", as used herein, mean the joining of two members together for the conveyance of persons or things therebetween. The term "coupled" or "connected" does not require contact, and can include electrical, magnetic, communication, or other types of coupling or connection. The terms "coupled" and "connected" also include the case where one or more intervening members are present.

[0057] The embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0058] Embodiment 1

[0059] The present embodiment provides a method for preparing a catalyst for hydrogen sulfide electric field enhanced decomposition, as shown in the formula (I), comprising: Figure 1

[0060] Mixing the first metal element source material and the second metal element source material into a precursor mixture according to a proportion;

[0061] After mixing the precursor mixture with thiourea according to a proportion, adding deionized water to perform ultrasonic magnetic stirring;

[0062] After the ultrasonic magnetic stirring is completed, adding sodium dodecyl sulfate to continue the ultrasonic magnetic stirring, thereby obtaining a catalyst precursor solution;

[0063] Performing a hydrothermal reaction on the catalyst precursor solution, vacuum filtering the obtained liquid, obtaining a precipitate, washing and drying the precipitate, and obtaining a target catalyst;

[0064] Grinding the target catalyst, silicon carbide powder, and oxide carrier powder or carbon-based carrier powder to obtain a composite catalyst;

[0065] Performing tabletting treatment on the composite catalyst, crushing and sieving the obtained sheet-shaped catalyst to obtain a catalyst for hydrogen sulfide electric field enhanced decomposition.

[0066] ​The embodiment adopts a double metal sulfide catalyst; wherein the first metal element is Mo, V, W, Cr, etc. Group IVB-VIB metal sulfide; the second metal element is Na, K, Fe, Co, Ni, etc. Group IA and Group VIII metal element sulfide; the embodiment takes Mo-Fe-S as an example, and the molybdenum (Mo) source material and the iron (Fe) source material are mixed in proportion to form a precursor mixture.

[0067] As an alternative embodiment, the molybdenum source material and the iron source material are sodium molybdate MoNa2O4 and ferric chloride FeCl3, respectively.

[0068] As an alternative embodiment, the first metal element source material and the first metal element source material are mixed in a mass ratio of 1:1-3.

[0069] Further, the first metal element source material and the first metal element source material are mixed in a mass ratio of 1:2.9-3.

[0070] As an alternative embodiment, thiourea CH4N2S is the precursor of S element in the catalyst.

[0071] As an alternative embodiment, the precursor mixture and thiourea are mixed in a mass ratio of 1:0.5-1.

[0072] Further, the precursor mixture and thiourea are mixed in a mass ratio of 1:0.8-1.

[0073] As an alternative embodiment, the mass of deionized water to the mass of the mixture of the precursor mixture and thiourea is 140-145:1.

[0074] As an alternative embodiment, after adding deionized water, ultrasonic magnetic stirring is performed for 15-30 min.

[0075] Further, after adding deionized water, ultrasonic magnetic stirring is performed for 30 min.

[0076] As an alternative embodiment, the mass ratio of sodium dodecyl sulfate C 12 H 25 SO4Na to the second metal element source material is 1:0.9-1, and sodium dodecyl sulfate C 12 H 25 SO4Na is added as a foaming agent to promote the catalyst particles to be of nanoscale.

[0077] As an alternative embodiment, after adding sodium dodecyl sulfate, ultrasonic magnetic stirring is performed for 15-30 min.

[0078] Further, after adding sodium dodecyl sulfate, ultrasonic magnetic stirring is performed for 20 min.

[0079] In the present embodiment, the catalyst precursor solution is divided into 100 ml polytetrafluoroethylene lining, loaded into a stainless steel high-pressure reactor, and hydrothermally reacted at 180°C for 12-18h.

[0080] Further, the hydrothermal reaction is preferably 16h.

[0081] In the present embodiment, the black precipitate obtained after the reaction is completed needs to be washed. The liquid obtained by hydrothermal reaction is vacuum filtered to obtain a black precipitate, which is washed during vacuum filtration; the washing process is as follows: rinse with excess deionized water, replace the excess alcohol after the filtrate is completely filtered, repeat the operation (deionized water and alcohol alternately) after the alcohol filtrate is completely filtered.

[0082] As an alternative embodiment, the washing process is repeated 3-6 times.

[0083] Further, the washing process is repeated 5 times.

[0084] In the present embodiment, the washed black precipitate is dried; specifically: the black precipitate is loaded into a clean container and placed in a vacuum drying oven at 60°C for drying, thereby obtaining the dried target catalyst (Mo-Fe-S is taken as an example in the present embodiment).

[0085] As an alternative embodiment, the drying duration is 4-7 hours.

[0086] Further, the drying duration is 6 hours.

[0087] In the present embodiment, in order to ensure the stability of the electric field high-temperature coupled catalytic system, the target catalyst is mixed with a certain proportion of oxide carrier powder or carbon-based carrier powder, and silicon carbide SiC powder.

[0088] As an alternative embodiment, the oxide carrier powder or carbon-based carrier powder can be selected from alumina Al2O3, calcium hydroxide Ca(OH)2, zeolite (Al2O3) x (SiO2) y or activated carbon, etc.; Al2O3 powder is taken as an example in the present embodiment.

[0089] As an alternative embodiment, 1g of oxide carrier powder or carbon-based carrier powder needs to be doped with 0.05-0.15g of target catalyst powder, and 1g of oxide carrier powder or carbon-based carrier powder needs to be doped with 0.1-0.5g of SiC powder, to form a catalyst suitable for electric field strengthening.

[0090] Furthermore, 1g of oxide carrier powder or carbon-based carrier powder needs to be doped with 0.06-0.1g of target catalyst powder, and 1g of oxide carrier powder or carbon-based carrier powder needs to be doped with 0.1-0.2g of SiC powder.

[0091] As an optional embodiment, the target catalyst, oxide support powder or carbon-based support powder and silicon carbide powder are mixed and ground in a mortar for 5-10 minutes.

[0092] Furthermore, the grinding time is 6-10 minutes.

[0093] In this embodiment, in order to ensure the permeability of the catalyst bed, the composite catalyst powder should be processed into particles of appropriate particle size; specifically: the composite catalyst is first pressed into tablets, and then the tablet catalyst is crushed and sieved to obtain a catalyst for electric field enhanced catalytic H2S decomposition.

[0094] As an optional embodiment, the pressure range during tableting is 15-24 MPa.

[0095] Furthermore, the pressure range during tableting is 20-24 MPa.

[0096] As an optional embodiment, the tableting process lasts for 5-10 minutes.

[0097] Furthermore, the tableting process lasts for 5-8 minutes.

[0098] As an optional embodiment, the sieve mesh specification is 18-40 mesh.

[0099] Furthermore, the sieve mesh specification is 20-40 mesh.

[0100] In this embodiment, the catalyst comprises a bimetallic sulfide catalyst, an oxide or carbon-based support, and SiC doped in specific ratios. This catalyst comprises multiple components that enhance the catalyst's adsorption capacity for H2S gas while ensuring the electric field stability of the catalyst bed. Metal sulfides are generally semiconductors with strong electron transitions and high electrical conductivity, but they can easily short-circuit the catalyst bed, resulting in insufficient electric field strength. Therefore, doping with an oxide or carbon-based support can modulate the conductivity of the catalyst bed and increase the electric field strength. The addition of SiC can reduce the risk of discharge caused by low bed resistivity.

[0101] The embodiment adopts a hydrothermal method, which can obtain a catalyst active component with a specific morphology to adapt to the requirement of electric field strengthening, is easy to realize application in an industrial scene with high temperature and high pressure, and has small popularization difficulty; the active component and the catalyst carrier can be mixed through physical stirring, which can make the catalyst have good structural strength and anti-sintering capacity, and can simplify the preparation process with the help of strong adsorption of the carrier.

[0102] A specific embodiment of the catalyst preparation method is given below and is only used as an example.

[0103] (1) 0.1 g of MoNa2O4 and 0.32 g of FeCl3 powder were mixed, and then 0.3 g of thiourea powder was mixed, transferred to a beaker, 80 ml of deionized water was added, and ultrasonic magnetic stirring was performed, with a stirring time of 30 min; after stirring was completed, 0.28 g of sodium dodecyl sulfate was added to the mixed solution, and ultrasonic magnetic stirring was continued, with a stirring time of 20 min.

[0104] (2) The solution obtained in step (1) was transferred to a 100 ml polytetrafluoroethylene liner, and finally loaded into a matching high-pressure reaction kettle; the high-pressure reaction kettle was placed in a high-temperature oven for hydrothermal reaction, with a reaction temperature of 180℃ and a reaction time of 16 h.

[0105] (3) After the hydrothermal reaction was completed, the obtained sample was vacuum filtered to obtain a black precipitate; the black precipitate was further vacuum filtered, washed once with 50 ml of deionized water, and then washed once with 50 ml of alcohol; the above washing process was recorded as one washing; after 5 times of washing, the black precipitate sample was collected, dried at a temperature of 60℃ for 6 hours, and then a Mo-Fe-S catalyst was obtained.

[0106] (4) 0.05 g of the prepared Mo-Fe-S catalyst, 0.4 g of Al2O3 powder, and 0.05 g of SiC powder were placed in a mortar, and ground for 10 minutes to obtain a uniformly mixed composite catalyst.

[0107] (5) The composite catalyst obtained in step (4) was subjected to tabletting treatment, with a tabletting pressure of 20-24 MPa and a tabletting time of 6 min; the obtained sheet-shaped catalyst was manually broken, and the broken particles were sieved through a 20-40 mesh sieve to obtain 20-40 mesh catalyst particles, which were finally weighed and reserved.

[0108] As shown in Figure 2 , the voltammetric characteristics of the obtained catalyst.

[0109] Example 2

[0110] The embodiment provides a hydrogen sulfide electric field strengthening decomposition method, which comprises the following steps.

[0111] The catalyst is placed in the cylindrical electrode plate to form a catalyst bed; the catalyst is prepared by the method described in Example 1;

[0112] The cylindrical electrode plate is connected with the anode electrode rod and then placed in the reactor, and the cathode electrode rod is inserted in the catalyst bed;

[0113] The inert gas is filled into the reactor and heated until the target temperature is reached;

[0114] The mixed gas containing a specific concentration of H2S is filled into the reactor, and at the same time, an electric field is applied between the outside and the center of the catalyst bed to form a current path, so that the mixed gas is decomposed under the action of the electric field to obtain the target product.

[0115] In this embodiment, the inert gas is first filled into the reactor to prevent oxidation of the catalyst during heating; after the reaction section is heated to the target temperature, the inert gas is replaced by a mixed gas containing a specific concentration of H2S and inert gas; then by setting the electric field intensity, a high-voltage electric field is formed between the outside and the center of the catalyst bed to form a current path, so that the reaction gas is decomposed under the action of the electric field to obtain the target product.

[0116] As an alternative embodiment, the inert gas is N2.

[0117] This embodiment is inspired by electrocatalysis and plasma methods, and refers to the high-density electron transfer advantage of both. High-voltage direct current is applied between the outside and the center of the solid-state catalyst bed to break through the limitation of thermodynamic equilibrium on the reaction in the traditional high-temperature decomposition mode by adding an electric field.

[0118] It should be emphasized that the method of this embodiment is completely different from the traditional electrocatalysis method;

[0119] First, the method of this embodiment does not have a liquid phase or a molten state of electrolyte, and accordingly there is no span transfer of some anions and cations;

[0120] Second, since the method of this embodiment applies an electric field to the solid-state catalyst bed, the resistance of the catalyst bed is much larger than that of the liquid phase in electrocatalysis, and the applied voltage is in the range of 0.1-2kV, and the bed current is only 1-20mA, which is also one of the key elements that distinguishes it from the plasma method. The plasma method is a method of generating highly active plasma by voltage breakdown of the gas atmosphere, but the ionization of pure gas phase requires a higher voltage, basically higher than 10kV, in addition, the action time of plasma is longer, so the concentration is relatively high, and it is difficult to achieve continuous and efficient decomposition of H2S gas in a flowing state by this method. However, in this embodiment, after a small amount of current passes through the catalyst bed at a relatively low voltage, it can achieve the decomposition of flowing H2S with a relatively high concentration, which has a very considerable advantage.

[0121] The present embodiment utilizes electric field to assist the decomposition of H2S to produce hydrogen and sulfur, and the electric field shows a reinforcing effect. During the electric field process, a large number of hot electrons are generated, and the unidirectional current promotes the formation of regular flow state of these hot electrons, and promotes the electron transfer between H2S and the catalyst, which not only shows the intensification of the decomposition process of H2S, but also shows a certain synergistic effect with the catalyst.

[0122] In the present embodiment, the reaction temperature is set to 400-700°C.

[0123] According to the thermodynamic equilibrium limit, the temperature is much lower than the temperature (above 1200°C) when a higher conversion rate is achieved by conventional heating; in addition, the present embodiment adopts a mode coupled with the traditional high-temperature mode, which is more easy to realize and apply the process.

[0124] In the present embodiment, the catalyst particles are filled in the reaction area to form a catalyst bed layer with micro-pores, and the electric field is formed between the outside and the center of the catalyst bed layer, and the electric field strength is shown as the voltage strength per unit length of the catalyst bed layer in the current direction. With the increase of the electric field strength, the conversion rate of H2S decomposition gradually increases.

[0125] As an alternative embodiment, the electric field strength is set to 0-0.2 kV / mm.

[0126] Further, the electric field strength is set to 0.04-0.2 kV / mm.

[0127] As an alternative embodiment, the gas flow rate is set to 50-120 ml / min.

[0128] Further, the gas flow rate is set to 50-100 ml / min.

[0129] A specific embodiment of the method of electric field reinforced catalytic H2S decomposition under different electric field strengths is given below.

[0130] (1) 0.5 g of Mo-Fe-S composite catalyst particles are placed in a cylindrical electrode plate and fixed, and the cylindrical electrode plate connected with the anode electrode rod is placed in the reactor, and the cathode electrode rod is inserted into the catalyst bed layer, and the above combination is placed in the heat source supply device, the furnace temperature is set to 700°C, the heating rate is 10°C / min, N2 is introduced, and the flow rate is set to 100 ml / min.

[0131] (2) When the furnace temperature reaches the target temperature, H2S gas is introduced, the total gas flow rate is kept at 100 ml / min, and the mixed gas is adjusted to 10% H2S-N2 mixed gas.

[0132] (3) When the furnace temperature reaches the target temperature, the direct current high voltage power supply is turned on at the same time, the voltage intensity U = 0.2 kV, the electric field intensity E = U / r = 0.04 kV / mm, r is the radius of the reaction device, the electric field enhanced catalytic H2S decomposition reaction is carried out and the target product is quantitatively analyzed.

[0133] (4) Repeat the operation steps (1)-(3), the difference is that the voltage intensity U = 0.4 kV, the electric field intensity E = U / r = 0.08 kV / mm.

[0134] (5) Repeat the operation steps (1)-(3), the difference is that the voltage intensity U = 0.6 kV, the electric field intensity E = U / r = 0.12 kV / mm.

[0135] (6) Repeat the operation steps (1)-(3), the difference is that the voltage intensity U = 0.8 kV, the electric field intensity E = U / r = 0.16 kV / mm.

[0136] (7) Repeat the operation steps (1)-(3), the difference is that the voltage intensity U = 1.0 kV, the electric field intensity E = U / r = 0.20 kV / mm, the bed current is not more than 9 mA.

[0137] According to the catalyst volt-ampere characteristic curve shown in Figure 2 , the bed voltage is continuously increased with the continuously increasing of the current, in this process, a large number of hot electrons are generated in the reaction area and gradually active with the increase of the current, the high active hot electrons promote the decomposition and conversion of H2S; but then, the current flux increases, due to the catalyst in the form of particles, too high voltage may cause excessive hot electrons to gather at the tip of the particles, partial discharge occurs, so that the macroscopic voltage of the bed no longer increases, even a small decrease occurs. Therefore, in order to reduce the influence of the partial discharge between the beds on the stability of the bed, the bed current is required to be not more than 9 mA.

[0138] The data obtained from the five experiments of steps (3)-(7) are summarized, as shown in Figure 3 , it is shown that at the reaction temperature of 700℃, the conversion rate of H2S is rapidly increased with the increase of the electric field intensity. In this reaction process, the composite catalyst and the electric field realize a specific synergistic effect, the generation and continuous transfer of hot electrons on the catalyst effectively promote the bond breaking and decomposition of H2S molecules.

[0139] The data show that under the conventional method at 700℃, the conversion rate of the present catalyst is 9.835%, while under the electric field intensity of 0.20 kV / mm, the conversion rate of H2S exceeds 55%, achieving more than four times growth. This obviously highlights the promotion effect of the present method on H2S decomposition, effectively breaking through the limit of the thermal equilibrium conversion rate of H2S, achieving short conversion equilibrium time and long effective conversion time, good system stability, relatively small energy consumption, good sintering resistance of the catalyst, high durability, and can continuously and stably achieve high-efficiency decomposition of H2S for a long time.

[0140] Next, a specific embodiment of the electric field enhanced catalytic H2S decomposition method at different temperatures is given.

[0141] 0.5 g of Mo-Fe-S composite catalyst particles were placed in a cylindrical electrode plate and fixed, and the cylindrical electrode plate connected with the anode electrode rod was placed in the reactor, the cathode electrode rod was inserted into the catalyst bed, the above combination was placed in the heat source supply device, 100 ml / min of inert gas (N2) was introduced, the reaction zone was heated to 400-700℃, the temperature interval was 50℃, and the temperature response performance of the catalyst under a specific electric field intensity was verified. After the temperature was raised to the target temperature, the atmosphere was changed to 10% H2S / N2 atmosphere at 100 ml / min, and after the conversion was stable, the experimental data was recorded. The electric field was added, the electric field intensity was adjusted to 1 kV, an electric field intensity of 0.2 kv / mm was formed, and the conversion was stable, and the experimental data was recorded.

[0142] The experimental results are shown in Figure 4 As can be seen from the table, under the traditional heating method, the conversion rate gradually increases with the increase of temperature, and the highest conversion rate is 9.81% at 700℃. However, after the electric field is added, the H2S conversion rate at different temperatures has a small increase, which is due to the synergistic effect of the electric field and the catalyst filling the energy gap at low temperature, mainly manifested in that at 400℃, the conversion rate can reach about 46%, while the conventional catalyst at this temperature is almost 0. At high temperature, the conversion rate is only increased by about 17% at 700℃ compared with 400℃ under the same electric field intensity, which is smaller than the nearly 300% increase under the conventional condition. However, this rule first highlights the superior ability of the catalyst and the electric field to enhance the catalytic decomposition of H2S, promotes the redox process through specific hot electron transport, greatly reduces the activation energy of the reaction and breaks through the thermodynamic limit of the reaction. Secondly, the synergistic effect of the electric field and the catalyst has excellent low-temperature characteristics, which can achieve high conversion at low temperature while ensuring low energy consumption, and has great potential for industrial application. In addition, the catalyst can maintain better strength structure and better catalytic activity at low temperature, reducing the sintering probability.

[0143] The application of low temperature is the advantage of the synergy of catalyst and electric field. The conventional heating no longer needs high energy consumption to reach a high reaction temperature. The electric field strengthening method can achieve higher input energy utilization and reduce the reaction activation energy due to its excellent synergy with the catalyst and the excitation of more hot electron transfer. Compared with other catalytic methods, the method has the advantages of simple operation and high energy utilization.

[0144] Embodiment 3

[0145] As shown in Figure 5 , the embodiment provides a hydrogen sulfide electric field strengthening decomposition device, which comprises a high-temperature catalytic device and an electric field strengthening device.

[0146] The high-temperature catalytic device provides heat for the H2S decomposition reaction, and comprises a reactor 7, an infrared temperature measuring device 1 arranged at one end of the reactor, and a heat source supply device 6 arranged outside the reactor. The reactor 7 is internally provided with a catalyst bed layer 10, and the catalyst bed layer 10 is internally filled with a catalyst.

[0147] As an alternative embodiment, the heat source supply device 6 is a high-temperature tube furnace.

[0148] As an alternative embodiment, the reactor 7 is a quartz glass tube with an inner diameter d = 2r = 5 mm.

[0149] As an alternative embodiment, the two ends of the reactor are respectively provided with a gas inlet 2 and a gas outlet 3. The gas inlet 2 is connected to a mixed gas of a certain proportion of H2S and N2, the gas outlet 3 is connected to a sulfur condensation and collection device through a pipeline, and the gas is detected by gas chromatography after being absorbed by an alkali solution to remove excess H2S.

[0150] In the embodiment, the electric field strengthening device is coupled with the high-temperature catalytic device to provide a direct-current high voltage for the catalyst bed layer. The electric field strengthening device comprises an anode electrode rod 4, a cathode electrode rod 5, a cylindrical electrode plate 8, and a direct-current high-voltage power supply 9.

[0151] As shown in Figures 6(a)-6(c) , the cylindrical electrode plate 8 is placed on the catalyst bed layer 10, and the cylindrical electrode plate 8 is in close contact with the catalyst to form a stable current path.

[0152] The anode electrode rod 4 is inserted from the gas inlet side of the high-temperature catalytic device and connected with the cylindrical electrode plate 8 to form a uniform anode cylindrical electrode. One end of the cathode electrode rod 5 is inserted into the center of the catalyst bed layer, and the other end is inserted out of the gas outlet side of the high-temperature catalytic device, so that a uniform current is formed from the periphery to the center of the catalyst bed layer.

[0153] The direct-current high-voltage power supply 9 provides a stable direct-current voltage and current for the catalyst bed layer.

[0154] As an alternative embodiment, the anode electrode rod, the cathode electrode rod and the cylindrical electrode plate are all made of stainless steel; the cathode is required to have good grounding.

[0155] Figure 5 Only the vertical state of the device is shown, and in actual application, both the horizontal and vertical states can be used.

[0156] The above describes the specific embodiments of the present application in combination with the drawings, but is not a limitation on the protection scope of the present application, and those skilled in the art should understand that various modifications or changes made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A method for producing a catalyst for hydrogen sulfide electric field enhanced decomposition, characterized by, The application relates to a preparation method of a catalyst for hydrogen sulfide electric field enhanced decomposition. The first metal element source material and the second metal element source material are mixed into a precursor mixture in proportion; wherein the first metal element source material and the second metal element source material are mixed in a mass ratio of 1:1-3; the first metal element is Mo or W, and the second metal element is Fe, Co or Ni; The precursor mixture is mixed with thiourea in proportion, and then deionized water is added for ultrasonic magnetic stirring; wherein the precursor mixture and the thiourea are mixed in a mass ratio of 1:0.5-1; After the ultrasonic magnetic stirring is completed, sodium dodecyl sulfate is added to continue the ultrasonic magnetic stirring, thereby obtaining a catalyst precursor solution; The catalyst precursor solution is subjected to a hydrothermal reaction, the obtained liquid is vacuum filtered, a precipitate is obtained, and the precipitate is washed and dried to obtain a target catalyst; wherein the hydrothermal reaction is a hydrothermal reaction at 180 DEG C for 12-18 h; The target catalyst, silicon carbide powder and oxide carrier powder or carbon-based carrier powder are ground to obtain a composite catalyst; The oxide carrier powder or the carbon-based carrier powder is mixed with the target catalyst in a ratio of 1:0.05-0.15, and the oxide carrier powder or the carbon-based carrier powder is mixed with the silicon carbide powder in a ratio of 1:0.1-0.5; The composite catalyst is subjected to tabletting treatment, the obtained sheet-shaped catalyst is crushed and sieved to obtain a catalyst for hydrogen sulfide electric field enhanced decomposition.

2. The method of claim 1, wherein the catalyst is prepared by the steps of: The mass ratio of the deionized water to the mass of the precursor mixture and the thiourea after mixing is 140-145:

1.

3. The method for preparing a catalyst for electric field enhanced decomposition according to claim 1, wherein: The mass ratio of the sodium dodecyl sulfate to the second metal element source material is 1:0.9-1.

4. The method of claim 1, wherein the catalyst is prepared by the steps of: The ultrasonic magnetic stirring time ranges from 15 min to 30 min.

5. The method for preparing a catalyst for electric field enhanced decomposition according to claim 1, wherein: The pressure during the tabletting treatment ranges from 15 MPa to 24 MPa; and the tabletting treatment duration ranges from 5 min to 10 min.

6. The method of claim 1, wherein the catalyst is prepared by the steps of: The sieve mesh size for sieving ranges from 18 meshes to 40 meshes.

7. A method for hydrogen sulfide electric field enhanced decomposition, the method comprising: providing a hydrogen sulfide containing fluid; and applying an electric field to the hydrogen sulfide containing fluid. The application relates to a preparation method of a catalyst for hydrogen sulfide electric field enhanced decomposition. The catalyst is placed in a cylindrical electrode plate to form a catalyst bed layer; The catalyst is prepared by the catalyst preparation method for electric field enhanced decomposition according to any one of claims 1-6; The cylindrical electrode plate is connected with an anode electrode rod and is placed in a reactor, and a cathode electrode rod is inserted into the catalyst bed layer; Inert gas is filled into the reactor and heated until the target temperature is reached; The mixed gas containing hydrogen sulfide with a specific concentration is filled into the reactor, and an electric field is applied to the outside and the center of the catalyst bed layer to form a current path, so that the mixed gas is decomposed under the action of the electric field to obtain a target product.

8. An electric field enhanced catalytic hydrogen sulfide decomposition method as claimed in claim 7, characterized in that, The intensity of the electric field ranges from 0.04 kV / mm to 0.2 kV / mm, the current of the catalyst bed layer ranges from 1 mA to 20 mA, and the reaction temperature is set to 400 DEG C-700 DEG C.

9. A hydrogen sulfide electric field enhanced decomposition device, characterized by, The application relates to a hydrogen sulfide electric field enhanced decomposition method according to any one of claims 7-8, which comprises a high-temperature catalytic device and an electric field enhancement device; The high-temperature catalytic device comprises a reactor and a heat source supply device for heating the reactor, and the reactor is provided with a catalyst bed layer; The electric field enhancement device comprises an anode electrode rod, a cathode electrode rod and a cylindrical electrode plate. The cylindrical electrode plate is in contact with the catalyst, the anode electrode rod is inserted from the gas inlet side of the high-temperature catalytic device and connected with the cylindrical electrode plate, one end of the cathode electrode rod is inserted into the center of the catalyst bed layer, and the other end is inserted out from the gas outlet side of the high-temperature catalytic device, so that a uniform current from the periphery to the center is formed in the catalyst bed layer.

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