Preparation method and preparation system of sulfur-carbon composite material

Abstract

The application provides a preparation method and a preparation system of a sulfur-carbon composite material, and comprises: an up-flowing fluidized bed device used for catalytic cracking of H2S to obtain a cracking product; a gas purification and separation device in communication with the up-flowing fluidized bed device, used for separating H2 in the cracking product to obtain a mixed gas containing sulfur vapor and residual unreacted H2S; and a down-flowing fluidized bed device in communication with the gas purification and separation device, used for vapor deposition of the sulfur vapor into the pore structure of a porous carbon material. The application generates sulfur vapor and H2 through thermal cracking of H2S, and then embeds the sulfur vapor into the pores of the porous carbon material in a vapor deposition manner, so that the uniform loading of sulfur on the carbon material is realized, and the obtained sulfur-carbon composite material can be used as an energy storage material. The application realizes the harmless treatment of a large amount of H2S gas generated in the industrial field of mineral processing and reduces environmental pollution. In addition, the preparation system of the sulfur-carbon composite material provided by the application can also obtain H2 byproducts, promotes the recycling of H2 resources, and improves industrial efficiency.

Description

Technical Field

[0001] This invention relates to the field of energy storage materials technology, and in particular to a method and system for preparing a sulfur-carbon composite material. Background Technology

[0002] In the energy storage field, electrochemical energy storage is widely used due to its high response speed, energy density, and cycle life. Properly allocating storage resources can improve the flexibility of new energy power generation, reduce waste solar and wind power, and smooth power output. However, for large-scale electrochemical energy storage, the theoretical capacity of traditional cathode materials is limited, and their high price results in weak market competitiveness. Therefore, seeking cost-effective materials and reducing the cost per kilowatt-hour are key tasks for promoting the development and improving the economic viability of electrochemical energy storage.

[0003] Elemental sulfur (S8) is widely available, abundant, and inexpensive to produce, and is based on the S→S process. 2- The conversion between these phases gives it a high specific capacity (1675 mAh / g), making it a cost-effective and high-performance battery active material. In aqueous systems, sulfur cathodes often involve solid-liquid conversion during charge and discharge. However, elemental sulfur has extremely poor conductivity (≈5 × 10⁻⁶). -30 Scm -1 The low reaction constants of the electrode redox reactions lead to a kinetic mismatch in the entire battery system. This not only increases charge-discharge polarization but also easily generates side reactions such as hydrogen evolution, oxygen evolution, and irreversible phase formation, significantly impacting the energy efficiency and cycle stability of aqueous batteries. Furthermore, the short-chain sulfur (S) intermediates of the electrode reactions... x 2- Sulfur (x<4) is readily soluble in water, exhibiting an "ion shuttle" phenomenon between the positive and negative electrodes, which easily leads to a high self-discharge rate, severe energy loss in the system, and a decrease in cell cycle life. Furthermore, the sulfur cathode involves ion intercalation during the reaction process, and the reaction product M... x S y The volume of the electrode is much larger than that of the active material S8. For example, the volume expansion of iron-sulfur batteries (Fe-S) is approximately 32.6%, magnesium-sulfur batteries (Mg-S) is approximately 32.6%, lithium-sulfur batteries (Li-S) is approximately 72%, and sodium-sulfur batteries (Na-S) is approximately 160%. Such significant volume changes can easily cause irreversible deformation of the electrode, failure of the internal conductive network, and reduced utilization of the electrode material. Furthermore, problems such as electrode pulverization and detachment during cycling seriously threaten the cycle stability of sulfur-based batteries.

[0004] Loading elemental sulfur into the porous structure of carbon materials to prepare sulfur-carbon composite materials helps solve the above problems. The excellent conductivity of carbon materials improves the electrode kinetics of sulfur-carbon composite electrodes, and the three-dimensional porous structure suppresses ion shuttle while providing a buffer for iso-expansion during charge and discharge. Common methods for preparing sulfur-carbon composite electrode materials include: ① Molten sulfur wetting method: Sulfur and carbon materials are mixed and added to a fixed bed. An inert gas is introduced into the fixed bed, and the temperature is heated to 155-165℃. Capillary action is used to draw the molten liquid sulfur into the pores. However, due to the presence of many non-penetrating pores in the carbon material, the wettability between the liquid sulfur and the carbon material surface is poor. Capillary action alone fails to fill the carbon pores completely, resulting in uneven loading inside and outside the carbon material particles. ② Solvent wetting method: Sulfur is dissolved in an organic solvent and then used to wet the carbon material. After removing the solvent, the loaded product is obtained.

[0005] However, both of the above methods have problems such as uneven sulfur loading, difficulty in accurately controlling the amount of sulfur loading, and long reaction time. The sulfur-carbon composite materials prepared have poor performance and are difficult to prepare on a large scale. Summary of the Invention

[0006] In view of the above-mentioned problems in the prior art, the present invention provides a method and system for preparing sulfur-carbon composite materials, which can synthesize high-performance sulfur-carbon composite materials with controllable loading and uniform loading inside and outside the particles on a large scale.

[0007] The specific details of the invention are as follows:

[0008] In a first aspect, the present invention provides a system for preparing sulfur-carbon composite materials, comprising:

[0009] An upward fluidized bed device is used for the catalytic cracking of H2S to obtain cracking products;

[0010] A gas purification and separation device connected to the upward fluidized bed device is used to separate H2 from the pyrolysis products to obtain a mixed gas containing sulfur vapor and remaining unreacted H2S.

[0011] A downflow fluidized bed device connected to the gas purification and separation device is used to deposit the sulfur vapor into the pore structure of the porous carbon material.

[0012] Optionally, the upward fluidized bed device is equipped with a heating unit for controlling the temperature of the catalytic cracking zone of the upward fluidized bed device to be 500-1500℃.

[0013] Optionally, the gas purification and separation device is equipped with a temperature control unit for adjusting the temperature inside the gas purification and separation device to 200-400℃;

[0014] Optionally, the downflow fluidized bed device is equipped with a gradient temperature control unit to create a cold flow zone so that sulfur vapor gradually cools down along the flow direction and is vapor-deposited into the pore structure of the porous carbon material.

[0015] Optionally, the upward fluidized bed device is further provided with a catalyst inlet, an H2S gas inlet, and a catalyst outlet;

[0016] The gas purification and separation device is also equipped with an H2 outlet;

[0017] The downflow fluidized bed device is also equipped with a porous carbon material inlet and a sulfur-carbon composite material outlet.

[0018] Optionally, the downflow fluidized bed device is connected to the upflow fluidized bed device, and the remaining gas in the downflow fluidized bed device is returned to the upflow fluidized bed device via a connecting pipe for cyclic pyrolysis.

[0019] In a second aspect, the present invention provides a method for preparing a sulfur-carbon composite material, the method being applicable to the sulfur-carbon composite material preparation system described in the first aspect above, the method comprising:

[0020] The temperature of the fluidization zone of the upward fluidized bed device is controlled at 500-1500℃. The thermal cracking catalyst and H2S gas are introduced into the upward fluidized bed device, so that the H2S gas undergoes thermal cracking under the action of the catalyst. The obtained sulfur-containing vapor and H2 cracking products enter the gas purification and separation device through the connecting pipe.

[0021] Under the action of the gas purification and separation device, H2 in the pyrolysis products is separated and discharged, and the remaining sulfur-containing vapor and unreacted H2S mixed gas enter the downflow fluidized bed device through the connecting pipe.

[0022] Porous carbon material is introduced into the downward fluidized bed device, and the temperature of the downward fluidized bed device is controlled to decrease gradually along the gas flow direction to form a cold flow region. When sulfur-containing vapor flows through the cold flow region, it is deposited in the pore structure of the porous carbon material to obtain the sulfur-carbon composite material. The remaining gas is returned to the upward fluidized bed device through a connecting pipe for recycling.

[0023] Optionally, the pyrolysis catalyst includes oxides of Fe, Al, V or Mo, and the H2S gas flow rate introduced into the upward fluidized bed device is 10-2000 L / min.

[0024] Optionally, the upper temperature limit of the cold flow zone is 200°C, and the lower temperature limit is 50°C.

[0025] Optionally, the porous carbon material is pure carbon material, carbon material modified by heteroatom doping, nano-carbon material, or carbon material;

[0026] The pure carbon material includes graphite and activated carbon;

[0027] In the carbon material modified by heteroatom doping, the heteroatoms include one or more of nitrogen, boron, sulfur, phosphorus, and oxygen;

[0028] The nano-carbon material is carbon nanotube, graphene, carbon nanofiber, or nanoporous carbon.

[0029] The porous carbon material has a particle size of no more than 300 μm and a surface area of ​​20 m². 2 / g~3000m 2 / g, pore volume of 0-2ml / g, tap density of 0.1~1.5g / cm³ 3 .

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] The present invention provides a sulfur-carbon composite material preparation system, comprising: an upward fluidized bed device for catalytic cracking of H2S to obtain cracking products; a gas purification and separation device connected to the upward fluidized bed device for separating H2 from the cracking products to obtain a mixed gas containing sulfur vapor and remaining unreacted H2S; and a downward fluidized bed device connected to the gas purification and separation device for depositing the sulfur vapor into the pore structure of a porous carbon material.

[0032] The sulfur-carbon composite material preparation system provided by this invention can use H2S gas as a source of elemental sulfur. Through thermal decomposition, sulfur vapor and H2 are generated. The sulfur vapor is then embedded into the pores of porous carbon material via vapor-phase deposition, achieving a uniform loading of elemental sulfur on the carbon material. The resulting sulfur-carbon composite material can be used as an energy storage material. This system can harmlessly treat large amounts of H2S gas generated in industrial fields such as mineral processing, reducing environmental pollution. Furthermore, the sulfur-carbon composite material preparation system provided by this invention can also obtain H2 byproducts, promoting the recycling of H2 resources and improving industrial efficiency.

[0033] The present invention can also control the sulfur loading by adjusting parameters such as the H2S flow rate into the fluidized bed device, reaction time, temperature, and carbon material retention time, thereby controlling the overall specific capacity of the active material. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram of the preparation system for sulfur-carbon composite materials provided in an embodiment of the present invention is shown;

[0036] Figure 2 A flowchart illustrating the preparation method of the sulfur-carbon composite material provided in an embodiment of the present invention is shown.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Upward fluidized bed device; 1-1, H2S gas inlet; 1-2, catalyst inlet; 1-3, catalyst outlet; 2. Gas purification and separation device; 2-1, H2 outlet; 3. Downward fluidized bed device; 3-1, carbon material inlet; 3-2, sulfur-carbon composite material outlet. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention. Furthermore, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of the present invention.

[0040] Specific experimental steps or conditions are not specified in the embodiments; they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products. Furthermore, the accompanying drawings are merely illustrative diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0041] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of this specification.

[0042] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0043] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] In a first aspect, the present invention provides a system for preparing sulfur-carbon composite materials. Figure 1 A schematic diagram of the preparation system for sulfur-carbon composite materials provided in an embodiment of the present invention is shown, as follows: Figure 1 As shown, the preparation system includes:

[0045] The upward fluidized bed device 1 is used for the catalytic cracking of H2S to obtain cracking products;

[0046] The gas purification and separation device 2, which is connected to the upward fluidized bed device 1, is used to separate H2 from the pyrolysis products and obtain a mixed gas containing sulfur vapor and the remaining unreacted H2S.

[0047] The downstream fluidized bed device 3, which is connected to the gas purification and separation device 2, is used to deposit the sulfur vapor into the pore structure of the porous carbon material.

[0048] See Figure 1 As shown, the upward fluidized bed device 1, the gas purification and separation device 2, and the downward fluidized bed device 3 are connected sequentially by pipelines. H2S gas enters through the H2S gas inlet 1-1 located at the bottom of the upward fluidized bed device 1. Catalytic cracking of H2S requires the action of a catalyst; therefore, a catalyst inlet 1-2 and a catalyst outlet 1-3 are also located at the bottom of the upward fluidized bed device 1 to facilitate the periodic replenishment and replacement of the catalyst, ensuring the smooth progress of H2S catalytic cracking. Catalytic cracking of H2S also requires heating; therefore, a heating unit is also provided in the upward fluidized bed device 1. The heating unit maintains the temperature of the sulfidation zone of the upward fluidized bed device 1 at 500-1500℃. The heated catalyst and H2S gas undergo catalytic cracking in the catalytic cracking zone. The generated sulfur vapor mixes with H2 and unreacted H2S, and as cracking products, enters the gas purification and separation device 2, which is connected to the upward fluidized bed device 1.

[0049] See also Figure 1 The gas purification and separation device 2 serves as a separation and recovery device for the byproduct H2, enabling the separation and recovery of H2. Simultaneously, the gas purification and separation device 2 is equipped with a temperature control unit to regulate the temperature within the device between 200-400℃, ensuring that sulfur vapor remains in a vapor state during H2 separation. The separated H2 is discharged from the system through the H2 outlet 2-1, while the remaining sulfur-containing vapor and unreacted H2S enter the downward fluidized bed device 3 connected to the gas purification and separation device 2.

[0050] See also Figure 1 The bottom of the downward fluidized bed device 3 is provided with a carbon material inlet 3-1. The downward fluidized bed device 3 is also provided with a gradient temperature control unit. The gradient temperature control unit controls the temperature in the downward fluidized bed device 3 to gradually decrease along the gas flow direction in order to create a cold flow zone for sulfur vapor. The upper limit of the temperature of the cold flow zone is 200℃ and the lower limit is 50℃. Since sulfur enters the downward fluidized bed device 3 from the top in the form of vapor and flows downward along the gas flow direction, it meets the upward carbon material blown in by the carbon material inlet 3-1 in the cold flow zone. The gas and solid phases mix and permeate each other, and the sulfur vapor gradually condenses and deposits into the pore structure of the carbon material. The gradient cooling cold flow zone ensures that after the sulfur vapor and carbon material come into contact and mix in the form of gas and solid phases, the sulfur vapor gradually condenses to achieve a uniform loading of elemental sulfur in the carbon material. The final sulfur-carbon composite material is discharged from the system through the sulfur-carbon composite material outlet 3-2. The remaining gaseous material contains uncracked H2S. Therefore, the remaining gas is fed into the upward fluidized bed device through the connecting pipeline for circulating cracking.

[0051] The sulfur-carbon composite material preparation system provided by this invention can use H2S gas as a source of elemental sulfur. Through thermal decomposition, sulfur vapor and H2 are generated. The sulfur vapor is then embedded into the pores of porous carbon material via vapor-phase deposition, achieving a uniform loading of elemental sulfur on the carbon material. This system can harmlessly treat large amounts of H2S gas generated in industrial fields such as mineral processing, reducing environmental pollution. Furthermore, the sulfur-carbon composite material preparation system provided by this invention can also obtain H2 byproducts, promoting the recycling of H2 resources and improving industrial efficiency.

[0052] This invention proposes a method for preparing sulfur-carbon composite electrode materials. The method utilizes the catalytic thermal cracking of industrial waste gas H2S in a fluidized bed. The generated H2 is separated by a gas purification device. A cold trap is then installed in the subsequent reaction apparatus to load the generated sulfur vapor into the pores of the blown-in carbon material. This preparation method not only reduces H2S emissions and increases H2 resource recycling, thus increasing industrial efficiency, but also produces sulfur-carbon composite materials with high efficiency, improved uniformity of sulfur loading, and controllable sulfur loading. The prepared sulfur-carbon composite materials can be used in organic battery systems, such as lithium-sulfur batteries and sodium-sulfur batteries, as well as in aqueous battery systems, such as zinc-sulfur batteries and iron-sulfur batteries.

[0053] Secondly, the present invention provides a method for preparing a sulfur-carbon composite material, the method being applicable to the sulfur-carbon composite material preparation system described in the first aspect above. Figure 2 A flowchart illustrating the preparation method of the sulfur-carbon composite material provided in this embodiment of the invention is shown, as follows: Figure 2 As shown, the method includes:

[0054] S1. Control the temperature of the fluidization zone of the upward fluidized bed device to 500-1500℃, and introduce the thermal decomposition catalyst and H2S gas into the upward fluidized bed device so that the H2S gas undergoes thermal decomposition under the action of the catalyst. The obtained sulfur-containing vapor and H2 decomposition products enter the gas purification and separation device through the connecting pipe.

[0055] S2. Under the action of the gas purification and separation device, H2 in the pyrolysis products is separated and discharged, and the remaining sulfur-containing vapor and unreacted H2S mixed gas enter the downward fluidized bed device through the connecting pipe.

[0056] S3. Porous carbon material is introduced into the downward fluidized bed device, and the temperature of the downward fluidized bed device is controlled to decrease gradually along the gas flow direction to form a cold flow region. When sulfur-containing vapor flows through the cold flow region, it is deposited in the pore structure of the porous carbon material to obtain the sulfur-carbon composite material. The remaining gas is returned to the upward fluidized bed device through the connecting pipe for recycling.

[0057] In practice, the catalyst is blown into the upward fluidized bed device through the catalyst feed port. At the same time, the H2S gas flow rate is controlled within the range of 10-2000 L / min according to the actual fluidization effect. The temperature of the fluidization zone of the upward fluidized bed device is controlled at 500-1500℃ through the heating device. During the fluidization process, the H2S gas undergoes thermal decomposition to generate H2 and sulfur vapor. Under high temperature conditions, the sulfur vapor exits the upward fluidized bed device along with the undecomposed H2S and H2 and enters the gas purification and separation device.

[0058] In practice, the temperature control unit of the gas purification and separation device adjusts the temperature inside the gas purification and separation device to 200-400℃. The gas separation process maintains a temperature of 200-400℃ to ensure that sulfur vapor remains in a gaseous state during H2 separation. Under the action of the gas purification and separation device, H2 exits the system in a high-purity state, thus achieving H2 separation. Sulfur vapor and unreacted H2S exit the gas purification and separation device in gaseous form and enter the downward fluidized bed device.

[0059] In practice, the downward fluidized bed device constructs a gradient cooling cold flow zone through a gradient temperature control unit. Along the gas flow direction, the temperature of the cold flow zone decreases gradually from 200℃ to 50℃. Sulfur vapor and unreacted H2S pass through the cold flow zone along the gas flow direction, come into contact with and permeate the upward carbon material. The temperature change from high to low causes the sulfur vapor to gradually condense and deposit into the pore structure of the carbon material, thereby achieving uniform deposition of elemental sulfur in the pores of the porous carbon material.

[0060] In specific implementation, this embodiment of the invention controls the sulfur loading of carbon materials by adjusting the residence time of carbon materials in the fluidized bed (not exceeding 48 hours). To improve the utilization rate of H2S, the remaining gas (including uncracked H2S) in the downflow fluidized bed device is introduced into the upflow fluidized bed device through a connecting pipe for circulating cracking.

[0061] In some embodiments, the pyrolysis catalyst comprises oxides of Fe, Al, V or Mo, and the H2S gas flow rate introduced into the upward fluidized bed device is 10-2000 L / min.

[0062] In some embodiments, the porous carbon material is pure carbon material, heteroatom-doped carbon material, nano-carbon material, or carbon material.

[0063] The pure carbon material includes graphite and activated carbon;

[0064] In the carbon material modified by heteroatom doping, the heteroatoms include one or more of nitrogen, boron, sulfur, phosphorus, and oxygen;

[0065] The nano-carbon material is carbon nanotube, graphene, carbon nanofiber, or nanoporous carbon.

[0066] The porous carbon material has a particle size of no more than 300 μm and a surface area of ​​20 m². 2 / g~3000m 2 / g, pore volume of 0-2ml / g, tap density of 0.1~1.5g / cm³ 3 .

[0067] The sulfur-carbon composite material preparation system provided by this invention can use H2S gas as a source of elemental sulfur. Through thermal decomposition, sulfur vapor and H2 are generated. The sulfur vapor is then embedded into the pores of porous carbon material via vapor-phase deposition, achieving a uniform loading of elemental sulfur on the carbon material. This system can harmlessly treat large amounts of H2S gas generated in industrial fields such as mineral processing, reducing environmental pollution. Furthermore, the sulfur-carbon composite material preparation system provided by this invention can also obtain H2 byproducts, promoting the recycling of H2 resources and improving industrial efficiency.

[0068] To enable those skilled in the art to more clearly understand the present invention, the following embodiments will be used to describe in detail the preparation method and preparation system of the sulfur-carbon composite material of the present invention.

[0069] by Figure 1 The system schematic diagram shown illustrates the system assembly, and the preparation of the sulfur-carbon composite material in Examples 1-6 is completed.

[0070] Example 1

[0071] The α-Fe2O3 catalyst is blown into the upward fluidized bed device 1 through the catalyst inlet 1-2, and the bed height is controlled at 20cm. At the same time, the flow rate of H2S gas entering through the H2S gas inlet 1-1 is controlled to be close to 50L / min. The temperature of the fluidization zone is controlled at 800℃ through the heating device. During the fluidization process, the H2S gas is thermally decomposed into H2 and S elemental substances. Under high temperature conditions, the sulfur elemental gas form (vapor) exits the upward fluidized bed device 1 along with the undecomposed H2S and H2 and enters the gas purification and separation device 2.

[0072] In the gas purification and separation device 2, the gas separation process maintains a temperature of 260℃. After gas purification, H2 is discharged from the system through the H2 outlet 2-1. After gas purification and separation, sulfur vapor and unreacted H2S exit the gas purification and separation device 2 in gas form and enter the downward fluidized bed device 3.

[0073] In the downflow fluidized bed unit 3, the gradient temperature control unit controls the lower limit temperature of the fluidization zone (cold flow zone) to 60℃. The carbon material blown in through the carbon material inlet 3-1 is mesoporous carbon with a specific surface area of ​​approximately 2200 m². 2 / g, pore volume is 1.2ml / g; in the cold flow region, elemental sulfur is uniformly deposited in the pores of the carbon material, achieving sulfur loading; the residence time of the carbon material in the downflow fluidized bed device 1 is 2h, and the finally obtained sulfur-carbon composite material is discharged from the system through the sulfur-carbon composite material outlet 3-2. Testing showed that the specific surface area of ​​the carbon material decreased to 680m². 2 The bulk density was increased from 0.53 g / ml to 0.9 g / ml. This embodiment effectively achieved the catalytic thermal decomposition of H2S, while simultaneously producing a sulfur-carbon composite material that can be used as an active material in sulfur-based batteries. The theoretical maximum sulfur loading can reach 70.7 wt%, and the actual thermogravimetric analysis of the obtained sulfur-carbon composite material showed a sulfur loading of 45.1%.

[0074] The remaining unpyrolyzed H2S gas in the downflow fluidized bed unit 3 is returned to the upflow fluidized bed unit 1 for recycling and pyrolysis.

[0075] Example 2

[0076] The FeS catalyst is blown into the upward fluidized bed device 1 through the catalyst inlet 1-2, and the bed height is controlled at 35cm. At the same time, the H2S gas flow rate at the H2S gas inlet 1-1 is controlled to be close to 10L / min. The temperature of the fluidization zone is controlled at 900℃ through the heating device. During the fluidization process, the H2S gas is thermally decomposed into H2 and S. Under high temperature conditions, the sulfur gas (vapor) exits the upward fluidized bed device 1 along with the undecomposed H2S and H2 and enters the gas purification and separation device 2.

[0077] In the gas purification and separation device 2, the gas separation process maintains a temperature of 260℃. After gas purification, H2 is discharged from the system through the H2 outlet 2-1. After gas purification and separation, sulfur vapor and unreacted H2S exit the gas purification and separation device 2 in gas form and enter the downward fluidized bed device 3.

[0078] In the downflow fluidized bed device 3, the gradient temperature control unit controls the lower limit temperature of the fluidization zone (cold flow zone) to 60℃. The carbon material blown in through the carbon material inlet 3-1 is mesoporous carbon with a specific surface area of ​​approximately 430 m². 2 / g; In the cold flow region, elemental sulfur is uniformly deposited in the pores of the carbon material, achieving sulfur loading; the residence time of the carbon material in the downflow fluidized bed device 1 is 1 hour, and the final sulfur-carbon composite material is discharged from the system through the sulfur-carbon composite material outlet 3-2. BET testing shows that the specific surface area of ​​the carbon material is reduced to 68 m². 2 / g, the actual thermogravimetric analysis showed that the sulfur loading of the obtained sulfur-carbon composite material was 35.6%.

[0079] The remaining unpyrolyzed H2S gas in the downflow fluidized bed unit 3 is returned to the upflow fluidized bed unit 1 for recycling and pyrolysis.

[0080] Example 3

[0081] V2O5 catalyst is blown into the upward fluidized bed device 1 through catalyst inlet 1-2, and the bed height is controlled at 15cm. At the same time, the H2S gas flow rate at H2S gas inlet 1-1 is controlled at close to 80L / min. The temperature of the fluidization zone is controlled at 1000℃ through the heating device. During the fluidization process, H2S gas is thermally decomposed into H2 and S elemental substances. Under high temperature conditions, the sulfur elemental gas form (vapor) exits the upward fluidized bed device 1 along with the undecomposed H2S and H2 and enters the gas purification and separation device 2.

[0082] In the gas purification and separation device 2, the gas separation process maintains a temperature of 260℃. After gas purification, H2 is discharged from the system through the H2 outlet 2-1. After gas purification and separation, sulfur vapor and unreacted H2S exit the gas purification and separation device 2 in gas form and enter the downward fluidized bed device 3.

[0083] In the downflow fluidized bed device 3, the gradient temperature control unit controls the lower limit temperature of the fluidization zone (cold flow zone) to 50℃. The carbon material blown in through the carbon material inlet 3-1 is mesoporous carbon with a specific surface area of ​​approximately 1650 m². 2 / g; In the cold flow region, elemental sulfur is uniformly deposited in the pores of the carbon material, achieving sulfur loading; the residence time of the carbon material in the downflow fluidized bed device 1 is 2 hours, and the finally obtained sulfur-carbon composite material is discharged from the system through the sulfur-carbon composite material outlet 3-2. BET testing shows that the specific surface area of ​​the carbon material is reduced to 860 m². 2 / g, the actual thermogravimetric analysis showed that the sulfur loading of the obtained sulfur-carbon composite material was 48.9%.

[0084] The remaining unpyrolyzed H2S gas in the downflow fluidized bed unit 3 is returned to the upflow fluidized bed unit 1 for recycling and pyrolysis.

[0085] Example 4

[0086] The α-Fe2O3 catalyst is blown into the upward fluidized bed device 1 through the catalyst inlet 1-2, and the bed height is controlled at 20cm. At the same time, the H2S gas flow rate at the H2S gas inlet 1-1 is controlled to be close to 30L / min. The temperature of the fluidization zone is controlled at 900℃ through the heating device. During the fluidization process, the H2S gas is thermally decomposed into H2 and S. Under high temperature conditions, the sulfur gas (vapor) exits the upward fluidized bed device 1 along with the undecomposed H2S and H2 and enters the gas purification and separation device 2.

[0087] In the gas purification and separation device 2, the gas separation process maintains a temperature of 260℃. After gas purification, H2 is discharged from the system through the H2 outlet 2-1. After gas purification and separation, sulfur vapor and unreacted H2S exit the gas purification and separation device 2 in gas form and enter the downward fluidized bed device 3.

[0088] In the downflow fluidized bed unit 3, the gradient temperature control unit controls the lower limit temperature of the fluidization zone (cold flow zone) to 60℃. The carbon material blown in through the carbon material inlet 3-1 is mesoporous carbon with a specific surface area of ​​approximately 1500 m². 2 / g, pore volume is 0.8ml / g; in the cold flow region, elemental sulfur is uniformly deposited in the pores of the carbon material, achieving sulfur loading; the residence time of the carbon material in the downflow fluidized bed device 1 is 8h, and the finally obtained sulfur-carbon composite material is discharged from the system through sulfur-carbon composite material outlet 3-2. Testing showed that the specific surface area of ​​the carbon material decreased to 380m². 2 / g, the actual thermogravimetric analysis showed that the sulfur loading of the obtained sulfur-carbon composite material was 54.7%.

[0089] The remaining unpyrolyzed H2S gas in the downflow fluidized bed unit 3 is returned to the upflow fluidized bed unit 1 for recycling and pyrolysis.

[0090] Example 5

[0091] The α-Fe2O3 catalyst is blown into the upward fluidized bed device 1 through the catalyst inlet 1-2, and the bed height is controlled at 20cm. At the same time, the H2S gas flow rate at the H2S gas inlet 1-1 is controlled to be close to 20L / min. The temperature of the fluidization zone is controlled at 900℃ through the heating device. During the fluidization process, the H2S gas is thermally decomposed into H2 and S. Under high temperature conditions, the sulfur gas (vapor) exits the upward fluidized bed device 1 along with the undecomposed H2S and H2 and enters the gas purification and separation device 2.

[0092] In the gas purification and separation device 2, the gas separation process maintains a temperature of 260℃. After gas purification, H2 is discharged from the system through the H2 outlet 2-1. After gas purification and separation, sulfur vapor and unreacted H2S exit the gas purification and separation device 2 in gas form and enter the downward fluidized bed device 3.

[0093] In the downflow fluidized bed device 3, the gradient temperature control unit controls the lower limit temperature of the fluidization zone (cold flow zone) to 60℃. The carbon material blown in through the carbon material inlet 3-1 is graphene, with a specific surface area of ​​approximately 2000 m². 2 / g; In the cold flow region, elemental sulfur is uniformly deposited in the pores of the carbon material, achieving sulfur loading; the residence time of the carbon material in the downflow fluidized bed device 1 is 0.5h, and the finally obtained sulfur-carbon composite material is discharged from the system through the sulfur-carbon composite material outlet 3-2. Testing showed that the specific surface area of ​​the carbon material decreased to 1120m². 2 / g, the actual thermogravimetric analysis showed that the sulfur loading of the obtained sulfur-carbon composite material was 50.1%.

[0094] The remaining unpyrolyzed H2S gas in the downflow fluidized bed unit 3 is returned to the upflow fluidized bed unit 1 for recycling and pyrolysis.

[0095] Example 6

[0096] The α-Fe2O3 catalyst is blown into the upward fluidized bed device 1 through the catalyst inlet 1-2, and the bed height is controlled at 20cm. At the same time, the H2S gas flow rate at the H2S gas inlet 1-1 is controlled to be close to 20L / min. The temperature of the fluidization zone is controlled at 900℃ through the heating device. During the fluidization process, the H2S gas is thermally decomposed into H2 and S. Under high temperature conditions, the sulfur gas (vapor) exits the upward fluidized bed device 1 along with the undecomposed H2S and H2 and enters the gas purification and separation device 2.

[0097] In the gas purification and separation device 2, the gas separation process maintains a temperature of 260℃. After gas purification, H2 is discharged from the system through the H2 outlet 2-1. After gas purification and separation, sulfur vapor and unreacted H2S exit the gas purification and separation device 2 in gas form and enter the downward fluidized bed device 3.

[0098] In the downflow fluidized bed unit 3, the gradient temperature control unit controls the lower limit temperature of the fluidization zone (cold flow zone) to 60℃. The carbon material blown in through the carbon material inlet 3-1 is mesoporous carbon with a specific surface area of ​​approximately 2100 m². 2 / g, pore volume is 1.1ml / g; in the cold flow region, elemental sulfur is uniformly deposited in the pores of the carbon material, achieving sulfur loading; the residence time of the carbon material in the downflow fluidized bed device 1 is 4h, and the finally obtained sulfur-carbon composite material is discharged from the system through sulfur-carbon composite material outlet 3-2. Testing showed that the specific surface area of ​​the carbon material decreased to 570m². 2 / g, the actual thermogravimetric analysis showed that the sulfur loading of the obtained sulfur-carbon composite material was 64.4%.

[0099] The remaining unpyrolyzed H2S gas in the downflow fluidized bed unit 3 is returned to the upflow fluidized bed unit 1 for recycling and pyrolysis.

[0100] Comparative Example 1

[0101] The preparation of sulfur-carbon composite materials using fixed-bed hot-melt elemental sulfur is briefly described below:

[0102] Sulfur powder and carbon materials were dry-mixed and placed in a tube furnace, with N2 introduced as a protective gas. The tube furnace was heated to 155°C and removed after 12 hours to obtain a sulfur-carbon composite material.

[0103] Performance testing

[0104] Taking an aqueous Fe-S battery as an example, the sulfur-carbon composite materials, acetylene black, and polyvinylidene fluoride (PVDF) binder generated in Examples 1-6 and Comparative Example 1 were mixed in an 8:1:1 ratio, and N-methylpyrrolidone (NMP) was added to prepare a slurry. The slurry was then coated onto carbon cloth, and its areal density was controlled to be 1.0-2.0 mg / cm³. 2 After coating, the electrode is transferred to a vacuum oven at 60°C for 12 hours to completely evaporate the NMP solvent. After cutting, it is used as the positive electrode of the battery.

[0105] Iron powder was mixed with Ketjen black and PVDF in an 8:1:1 ratio to prepare the negative electrode. A 0.5 mol / L FeSO4 solution was prepared as the electrolyte, and glass fiber was used as the battery separator. 2032 coin cells were assembled, and charge-discharge cycle tests were conducted using the 0.2 A / g method. The test results are shown in Table 1.

[0106] Table 1. Electrical performance test results of different sulfur-carbon composite materials

[0107]

[0108] It is easy to see from the examples and comparative examples that different types of carbon materials have certain changes in specific surface area and bulk density before and after loading; compared with Comparative Example 1, the specific surface area of ​​the material decreased significantly, and the bulk density increased significantly.

[0109] Through examples and comparative examples, it was found that the sulfur-carbon composite material prepared by H2S pyrolysis has better cycling performance. For carbon materials with different specific surface areas, the sulfur loading can be adjusted by adjusting the preparation process parameters such as H2S gas flow rate, pyrolysis temperature, and carbon material retention time.

[0110] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0111] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0112] The preparation method and system for a sulfur-carbon composite material provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A system for producing a sulfur-carbon composite material, characterized by comprising: include: An upward fluidized bed device is used for the catalytic cracking of H2S to obtain cracking products; A gas purification and separation device connected to the upward fluidized bed device is used to separate H2 from the pyrolysis products to obtain a mixed gas containing sulfur vapor and remaining unreacted H2S. A downflow fluidized bed device connected to the gas purification and separation device is used to deposit the sulfur vapor into the pore structure of the porous carbon material. The upward fluidized bed device is equipped with a heating unit to control the temperature of the catalytic cracking zone of the upward fluidized bed device to 500-1500℃; The gas purification and separation device is equipped with a temperature control unit for adjusting the temperature inside the gas purification and separation device to 200-400℃. The downflow fluidized bed device is equipped with a gradient temperature control unit to create a cold flow region, wherein the upper temperature limit of the cold flow region is 200 ℃ and the lower temperature limit is 50 ℃.

2. The system for preparing a sulfur-carbon composite material according to claim 1, wherein The upward fluidized bed device is also equipped with a catalyst inlet, an H2S gas inlet, and a catalyst outlet; The gas purification and separation device is also equipped with an H2 outlet; The downflow fluidized bed device is also equipped with a carbon material inlet and a sulfur-carbon composite material outlet.

3. The system for preparing a sulfur-carbon composite material according to claim 1, wherein The downflow fluidized bed device is connected to the upflow fluidized bed device, and the remaining gas in the downflow fluidized bed device is returned to the upflow fluidized bed device through the connecting pipe for cyclic pyrolysis.

4. A method for producing a sulfur-carbon composite material, characterized by, The method is applicable to the preparation system of the sulfur-carbon composite material according to any one of claims 1-3 above, and the method includes: The temperature of the fluidization zone of the upward fluidized bed device is controlled at 500-1500℃. The thermal cracking catalyst and H2S gas are introduced into the upward fluidized bed device, so that the H2S gas undergoes thermal cracking under the action of the catalyst. The obtained sulfur-containing vapor and H2 cracking products enter the gas purification and separation device through the connecting pipe. Under the action of the gas purification and separation device, H2 in the pyrolysis products is separated and discharged, and the remaining sulfur-containing vapor and unreacted H2S mixed gas enter the downflow fluidized bed device through the connecting pipe. Porous carbon material is introduced into the downward fluidized bed device, and the temperature of the downward fluidized bed device is controlled to decrease gradually along the gas flow direction to form a cold flow region. When sulfur-containing vapor flows through the cold flow region, it is deposited in the pore structure of the porous carbon material to obtain the sulfur-carbon composite material. The remaining gas is returned to the upward fluidized bed device through a connecting pipe for recycling.

5. The method of producing a sulfur-carbon composite material according to claim 4, characterized by, The pyrolysis catalyst includes oxides of Fe, Al, V or Mo, and the flow rate of H2S gas introduced into the upward fluidized bed device is 10-2000 L / min.

6. The method of producing a sulfur-carbon composite material according to claim 4, wherein The upper temperature limit of the cold flow region is 200 ℃, and the lower temperature limit is 50 ℃.

7. The method of producing a sulfur-carbon composite material according to claim 4, wherein The porous carbon material is pure carbon material, carbon material modified by heteroatom doping, nano-carbon material, or carbon material. The pure carbon material includes graphite and activated carbon; In the carbon material modified by heteroatom doping, the heteroatoms include one or more of nitrogen, boron, sulfur, phosphorus, and oxygen; The nano-carbon material is carbon nanotube, graphene, carbon nanofiber, or nanoporous carbon. The porous carbon material has a particle size of not more than 300 μm, a surface area of 20 m 2 / g~3000 m 2 / g, a pore volume of 0-2 ml / g, and a tap density of 0.1-1.5 g / cm 3 .

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