A reaction furnace, a reaction system and a strengthening method for promoting the reduction of SO2 to sulfur by solid carbon-based materials

Abstract

The present application relates to a kind of reaction furnace, reaction system and strengthening method of promoting solid carbon-based material reduction SO2 sulfur production.The present application proposes a kind of reduction reaction furnace, reaction system and strengthening method with electric heating in bottom for promoting carbon-based material gasification and reduction SO2, to solve the problems such as too high reaction temperature of carbon-based reducing agent, difficult temperature control, low quality of sulfur, etc.The carbon-based material is fed from the top of the reaction furnace, and reduces SO2 and produces CO reducing gas during moving downward.SO2 raw gas and part of reflux COS gas enter from the bottom of the reaction furnace, and the residual carbon in bottom slag is fully reacted by heating unit auxiliary temperature control.The product gas flowing out from the top of the reaction furnace is dusted, and then converted into H2S by downstream catalytic reaction, and then reacted with newly added SO2 to obtain high-quality sulfur by conventional Claus reaction.The method and reaction system can significantly improve the yield and quality of sulfur production, and reduce energy consumption, with good application prospect.

Description

Technical Field

[0001] This invention relates to the fields of materials processing, energy and environmental protection, and in particular to a reactor, reaction system and enhancement method for promoting the reduction of SO2 to sulfur from solid carbon-based materials. Background Technology

[0002] China's energy structure still relies heavily on fossil fuels such as coal. The combustion of coal produces a large amount of pollutants, with sulfur dioxide being one of the main emissions. With the increasingly stringent environmental protection requirements, sulfur dioxide emissions from coal-fired power generation, metal smelting, and petrochemical industries have become a key focus of flue gas treatment. Traditional limestone desulfurization stages consume large amounts of lime and water resources, and the desulfurization wastewater is difficult to treat. Furthermore, the byproduct, desulfurization gypsum, has low value, thus necessitating the search for new technologies for flue gas sulfur dioxide treatment. Meanwhile, elemental sulfur, a sulfur dioxide reduction product, has advantages such as ease of transportation and storage and high unit value among all sulfur-containing products. Therefore, reducing sulfur dioxide to sulfur is an important pathway for flue gas sulfur resource conversion. Among the reducing agents required for this process, coke is the lowest-cost option, and it is produced as a byproduct in industries such as power generation, metallurgy, and petrochemicals. Using coke for sulfur dioxide reduction to produce high-value sulfur can achieve the effect of waste resource utilization. However, coke has relatively weak reducing properties and usually requires high temperatures to reduce sulfur dioxide, resulting in relatively high energy input costs.

[0003] Patent CN1 15999507A discloses a combined process for coal-to-coke and sulfur production, proposing a coupling method for the resource recovery of coke and flue gas sulfur. Although this achieves coupling at the material level, the high energy input problem remains unresolved. Patent CN1 08726487A discloses a method for providing heat for SO2 reduction in coke using H2S combustion. H2S-rich gas is incinerated to generate high-temperature gas, which is then mixed with circulating gas and transported to a circulating fluidized bed carbothermal reduction tower. Under the action of a carbon-based reducing agent, SO2 is reduced to form a mixed gas. While this method provides some heat for SO2 reduction, the H2S combustion stage reduces sulfur resource recovery efficiency, sacrificing product for energy; its economic operating cost still needs improvement. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a reactor, reaction system, and enhancement method for promoting the reduction of SO2 to sulfur from solid carbon-based materials. This invention provides a reaction device and enhancement method for promoting the reduction of SO2 to sulfur from carbon-based materials. Through a top silo, a carbon-based material decomposition and SO2 deep reduction zone, an electrically heated auxiliary temperature control zone, and a slag cooling and heat recovery zone arranged sequentially from top to bottom, the reflux of COS, the reduction product of solid carbon-based materials, can be achieved. A Claus-like process is used to pre-reduce SO2 to elemental sulfur, reducing the difficulty of reducing sulfur-containing components in coke. This can improve sulfur yield and purity while reducing reaction energy consumption.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The first objective of this invention is to provide a reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials. The reactor comprises, from top to bottom, a top hopper, a carbon-based material decomposition and SO2 deep reduction zone, an electrically heated auxiliary temperature control zone, and a slag cooling and heat recovery zone. The top hopper is used for quantitative feeding of the carbon-based material. The carbon-based material decomposition and SO2 deep reduction zone is used to heat the carbon-based material, causing it to partially gasify and react with SO2, deeply reducing SO2 to COS, while simultaneously generating some excess CO reducing gas. The electrically heated auxiliary temperature control zone is used to appropriately increase the reaction temperature, ensuring that the remaining carbon-based material reacts fully with SO2 at a higher temperature. The slag cooling and heat recovery zone is used to cool the high-temperature slag generated after the reaction by contacting it with a low-temperature gas flow, and to rapidly heat the SO2 gas to be reduced by direct contact with the high-temperature slag.

[0007] Furthermore, the reactor also includes a slag outlet, a bottom SO2 gas inlet, a top outlet, and a reflux gas inlet. The slag outlet is located at the bottom of the reactor and is connected to a water-sealed sedimentation tank to discharge the high-temperature slag produced after the reaction. The bottom SO2 gas inlet is located at the bottom of the reactor and allows the SO2 gas to be reduced to enter. The top outlet is located at the top of the reactor and allows the gas produced after the reaction to flow out. The reflux gas inlet is located in the middle of the reactor, at the bottom of the carbon-based material decomposition and SO2 deep reduction zone and above the electrically heated auxiliary temperature control zone, between these two zones. The reflux gas inlet is used to partially reflux the gas from the top outlet of the reactor after dust removal and cooling to promote SO2 reduction and carbon-based material gasification.

[0008] Furthermore, the reactor also includes a two-stage rotary valve; the two-stage rotary valve is located between the top hopper and the carbon-based material decomposition and SO2 deep reduction zone; the two-stage rotary valve is used to prevent gas leakage while ensuring the solid carbon-based material.

[0009] Furthermore, the electric heating auxiliary temperature control zone includes an electric heating element, a heat storage shell, and an online slag scraping and slag loosening element; the electric heating element is connected to the heat storage shell; and the online slag scraping and slag loosening element is installed on the outer edge of the heat storage shell.

[0010] Furthermore, the heat storage shell is a heat storage block with an electric heating element insertion hole for inserting an electric heating element; the height of the heat storage block is 300-600mm and the width is 40-100mm; multiple heat storage shells are provided, and multiple heat storage blocks are arranged adjacent to each other; the gap between adjacent heat storage blocks is 50-200mm, through which high-temperature slag moves downward.

[0011] Furthermore, the online slag scraping and slag loosening element includes a scraper blade with external teeth for loosening slag; the online slag scraping and slag loosening element is a component made of heat-resistant metals such as 304H and 310s; the width of the online slag scraping and slag loosening element is 40-60mm.

[0012] Furthermore, the reactor has a diameter of 1000-3000 mm and a height that is 3-5 times the diameter; the reactor is lined with heat-insulating material and has external heat-insulating material.

[0013] Furthermore, the reactor includes a furnace chamber; the top hopper is located at the top of the furnace chamber; the carbon-based material decomposition and SO2 deep reduction zone is located in the upper middle part of the furnace chamber; the electric heating auxiliary temperature control zone is located in the lower middle part of the furnace chamber; and the slag cooling and heat recovery zone is located at the tail end of the furnace chamber.

[0014] Furthermore, an intermediate feeding section is provided between the top silo, the carbon-based material decomposition zone, and the SO2 deep reduction zone. The two-stage rotary valve is located on the intermediate feeding section between the top silo, the carbon-based material decomposition zone, and the SO2 deep reduction zone. The diameter of the intermediate feeding section is smaller than the diameter of the top silo, and the diameter of the intermediate feeding section is smaller than the diameter of the carbon-based material decomposition zone and the SO2 deep reduction zone.

[0015] Furthermore, the two-stage rotary valve comprises two rotary valves arranged sequentially from top to bottom.

[0016] Furthermore, the slag discharge outlet is located at the bottom of the furnace chamber of the reactor.

[0017] Furthermore, the bottom SO2 gas inlet of the reactor is located on the bottom side of the furnace chamber, and the position of the bottom SO2 gas inlet of the reactor is higher than the position of the slag discharge outlet.

[0018] Furthermore, the top outlet of the reactor is located on the top side of the furnace chamber, and the position of the top outlet of the reactor is lower than the position of the top hopper and higher than the position of the carbon-based material decomposition and SO2 deep reduction zone.

[0019] Furthermore, the reflux gas inlet of the reactor is located on the side of the middle part of the furnace chamber, and the position of the reflux gas inlet of the reactor is higher than the position of the electric heating auxiliary temperature control zone.

[0020] A second objective of this invention is to provide a reaction system comprising a furnace for promoting the reduction of SO2 to sulfur using solid carbon-based materials. The system further comprises a dust removal and cooling unit, a catalytic hydrolysis unit, an SO2 reduction-to-Claus reaction unit, and a cooling unit. The dust removal and cooling unit is connected to the furnace and is used to remove dust and cool the gas after the reaction. The catalytic hydrolysis unit is connected to the dust removal and cooling unit and is used to catalytically hydrolyze the gas after dust removal and cooling. The SO2 reduction-to-Claus reaction unit is connected to the catalytic hydrolysis unit and is used to react the gas after catalytic hydrolysis with the SO2 feed gas to convert it into sulfur gas. The cooling unit is connected to the SO2 reduction-to-Claus reaction unit and is used to cool the sulfur gas to recover liquid or solid sulfur products.

[0021] Furthermore, the dust removal and cooling unit includes conventional cyclone dust collectors, high-temperature ceramic filters, and other devices; the catalytic hydrolysis unit includes a catalytic hydrolysis reaction unit filled with an alumina-based catalytic packing layer, with a reaction temperature of 400-450℃; the SO2 reduction and conversion Claus reaction unit includes a conventional alumina-based two-stage reaction device, with a reaction temperature of 180-350℃; and the cooling unit includes a two-stage condenser cooler unit.

[0022] Furthermore, the reaction system also includes a water-sealed slag tank; the water-sealed slag tank is located below the reactor, the slag discharge outlet is connected to the slag discharge outlet, and the slag discharge outlet extends into the water-sealed slag tank.

[0023] Furthermore, the reaction system also includes a reflux fan, which is connected to the pipeline between the dust removal and cooling unit and the catalytic hydrolysis unit, as well as the reflux gas inlet of the reactor. Specifically, the inlet of the reflux fan is connected to the pipeline between the dust removal and cooling unit and the catalytic hydrolysis unit, and the outlet of the reflux fan is connected to the reflux gas inlet of the reactor.

[0024] Furthermore, the product gas flowing out of the reactor from the top, that is, from the top outlet of the reactor, is dedusted by the dust removal and cooling unit. 10%-30% of the gas flow is then dedusted by the high-temperature reflux fan after dust removal and cooling, and enters the reactor for recycling through the reflux gas inlet.

[0025] A third objective of this invention is to provide an enhanced method for promoting the reduction of SO2 to sulfur using solid carbon-based materials. This enhanced method is implemented through the aforementioned reaction system and includes the following steps:

[0026] S1. Solid carbon-based material enters the upper part of the furnace from the top hopper of the reactor, that is, the carbon-based material decomposition and SO2 deep reduction zone. As the carbon-based material moves downward, it is gradually heated and partially gasified in the carbon-based material decomposition and SO2 deep reduction zone, and then reacts with SO2 to deeply reduce SO2 to COs. At the same time, some excess CO reducing gas is generated. When the carbon-based material moves down to the middle and lower part of the reactor, the reaction temperature is increased by an electric heating auxiliary temperature control zone to ensure that the remaining carbon-based material reacts fully with SO2 at a higher temperature. The high-temperature slag produced after the reaction is finally cooled down by contacting the low-temperature airflow in the slag cooling and heat recovery zone and discharged from the reactor.

[0027] S2, SO2 gas to be reduced enters from the bottom of the reactor. It is heated by direct contact with high-temperature slag in the slag cooling and heat recovery zone and rises to the electrically heated auxiliary temperature control zone. At a higher temperature, it undergoes a reduction reaction with carbon-based materials and the CO produced by their gasification. The SO2 that is not fully reduced continues to flow upward and continues to react with carbon-based materials in the middle and upper parts of the furnace, gradually transforming into COS.

[0028] S3. The gas flowing out from the top of the reactor is cooled and dusted by the dust removal and cooling unit. Its main components are COS, CO and CO2. After passing through the catalytic hydrolysis unit, it reacts with SO2 raw material gas. In the SO2 reduction and conversion Claus reaction unit, through a series of conventional Claus reactions between COS, CO and SO2, it is finally converted into high-purity sulfur gas. Then, the liquid or solid sulfur product is recovered through the cooling unit.

[0029] Furthermore, the enhancement method includes the following steps:

[0030] S1. Solid carbon-based material is metered into the upper part of the furnace from the top hopper of the reactor via a two-stage rotary valve, specifically entering the carbon-based material decomposition and SO2 deep reduction zone. The two-stage rotary valve ensures solid material transport while preventing gas leakage. As the carbon-based material moves downward, it is gradually heated and partially gasified in the carbon-based material decomposition and SO2 deep reduction zone, reacting with SO2 to deeply reduce SO2 to COS, while simultaneously generating some excess CO reducing gas. When the carbon-based material moves to the middle and lower parts of the reactor, the reaction temperature is appropriately increased through an electrically heated auxiliary temperature control zone to ensure that the remaining carbon-based material reacts fully with SO2 at a higher temperature. The resulting high-temperature slag is cooled by contact with a low-temperature gas flow in the slag cooling and heat recovery zone and discharged from the reactor through the bottom slag outlet into a water-sealed slag tank.

[0031] S2. The SO2 gas to be reduced enters from the SO2 gas inlet at the bottom of the reactor. It is rapidly heated in the slag cooling and heat recovery zone by direct contact with the high-temperature slag and rises to the electrically heated auxiliary temperature control zone. At a higher temperature, it undergoes a reduction reaction with the carbon-based materials and the CO produced by their gasification. The SO2 that is not fully reduced continues to flow upward and continues to react with the carbon-based materials in the middle and upper parts of the furnace, gradually transforming into COS.

[0032] S3. To promote the rapid reduction of SO2 and the gasification of carbon-based materials, the gas flow from the top outlet of the reactor is partially refluxed after being refluxed and cooled by the dust removal and cooling unit. It then enters the reactor through the reflux gas inlet, using reducing gases such as COs and CO to promote the low-temperature reduction of SO2 and the gasification of carbon materials, thereby significantly increasing the production load of the reactor.

[0033] S4. The gas flowing out from the top outlet of the reactor is cooled and dusted by the dust removal and cooling unit. Its main components are COS, CO and CO2. Except for a portion of the gas being refluxed, the remaining gas is catalytically hydrolyzed by the catalytic hydrolysis unit and reacts with an appropriate amount of SO2 raw material gas. In the SO2 reduction and conversion Claus reaction unit, through a series of conventional Claus reactions between COS, CO and SO2, it is finally converted into high-purity sulfur gas. Then, the liquid or solid sulfur product is recovered through the cooling unit.

[0034] Furthermore, the SO2 reduction reactor utilizes solid carbon-based materials such as coal and coke, and mainly includes the following units: a top hopper, a carbon-based material decomposition and SO2 deep reduction zone, an electrically heated auxiliary temperature control zone, and a slag cooling and heat recovery zone. Among them, the top hopper is a quantitative feeding hopper for carbon-based materials at the top and a corresponding gas isolation unit; the middle and upper part of the furnace is the carbon-based material decomposition and SO2 deep reduction zone; the middle and lower part of the furnace is the electrically heated auxiliary temperature control zone, which includes electric heating elements, a heat storage shell, and online slag scraping and slag loosening elements; the tail end of the furnace is the slag cooling and heat recovery zone; and the bottom of the furnace is the slag discharge outlet, which is connected to the matching water-sealed slag settling tank.

[0035] Furthermore, the SO2 gas is high-concentration SO2 industrial flue gas, enriched and concentrated SO2 gas with a concentration of not less than 15%, an oxygen content of not more than 10%, and an optimal SO2 / O2 concentration ratio greater than 5. The SO2 gas to be reduced or the SO2 raw material gas entering from the bottom SO2 gas inlet of the reactor can be the SO2 gas mentioned above.

[0036] Furthermore, the carbon-based material is one or more of coke with low volatile content, activated carbon, and high-quality semi-coke, which are not prone to producing by-products such as tar during high-temperature reaction. The carbon-based material is granular, and its particle equivalent diameter is in the range of 5 to 50 mm.

[0037] Furthermore, the amount of carbon-based material conveyed from the top hopper into the top of the furnace is achieved by adjusting the rotation speed of the two-stage rotary valve, ensuring that no significant air intake or leakage occurs between the reactor and the outside environment during the feeding process.

[0038] Furthermore, the electric heating auxiliary temperature control zone of the reactor consists of a heat storage shell, online slag scraping and slag loosening elements installed on the outer edge of the heat storage blocks, and electric heating elements. The height of the heat storage blocks is 300–600 mm, and the width is 40–100 mm. The gaps between the heat storage blocks are 50–200 mm, through which the char and slag move downwards. Through electric heating or heat storage, the temperature of the electric heating auxiliary temperature control zone is maintained at 900–1100℃, ensuring sufficient reaction between SO2 and residual char in the high-temperature slag.

[0039] Furthermore, the online slag scraping and slag loosening elements arranged on the outer edge of the heat storage block are made of heat-resistant metals such as 304H and 310s, with a width of 40-60mm. In addition to having sharp scraping blades, they also have external teeth for loosening slag. This prevents sticky slag from adhering to the surface of the heat storage block and affecting the heat exchange effect, while the external teeth loosen the relatively dense slag layer during their movement, increasing its permeability.

[0040] Furthermore, the reaction temperature of the carbon-based material decomposition and SO2 deep reduction zone in the upper part of the reactor is 600-900℃. Its heat mainly comes from the exothermic reaction of the SO2 reduction process and the exothermic carbon oxidation generated by a small amount of oxygen in the gas stream. When the exothermic reaction is insufficient to maintain the required temperature, the electric heating element in the lower heat storage block is activated to supplement energy.

[0041] Furthermore, the reactor has a diameter of 1000–3000 mm and a height 3–5 times its diameter. The reactor is lined with insulating material and supplemented with external insulation. The apparent upward flow velocity of SO2, reflux gas, and other gases in the carbon layer (mainly the carbon layer within the decomposition and deep SO2 reduction zone of the carbon-based material) is 0.05–0.2 m / s, and the total residence time of the carbon-based material in the reactor is 0.5–3 h.

[0042] Furthermore, the gas flow from the top outlet of the reactor is partially refluxed after being refluxed and cooled by the dust removal and cooling unit. The reflux flow rate accounts for 10-50% of the gas flow rate from the reactor. The COs and CO in the gas flow rate are used to promote the low-temperature reduction of SO2 and the gasification of carbon-based materials.

[0043] Furthermore, this invention reduces the difficulty of reducing sulfur-containing components in coke by refluxing the COS reduction product of solid carbon-based materials and utilizing a Claus-like process to pre-reduce SO2 to elemental sulfur, thereby reducing reaction energy consumption.

[0044] Furthermore, in this invention, the COS pre-reduction of SO2 is an exothermic process that can provide a certain amount of heat replenishment, thereby further reducing the energy consumption of the reaction process.

[0045] Furthermore, the COS species in this invention promote the CO2 gasification of coke. While recovering sulfur, a portion of the coke can be converted into gasification gas components such as CO, which can reduce reaction energy consumption while increasing sulfur yield and purity.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1) This technical solution provides a furnace and reaction system for promoting the reduction of SO2 to sulfur by solid carbon-based materials. Addressing the problems of excessively high reaction temperature, difficulty in temperature control, and low sulfur quality caused by the direct reduction of SO2 to sulfur by carbon-based reducing agents, this solution proposes a reduction furnace and reaction system with bottom electric heating to promote the gasification of carbon-based materials and the reduction of SO2. This furnace and reaction system can utilize the partial reflux of COS, an intermediate product of SO2 reduction, to promote SO2 reduction and carbon material gasification, thereby significantly improving the yield and quality of sulfur production and reducing energy consumption.

[0048] 2) This technical solution provides a reactor and reaction system for promoting the reduction of SO2 to sulfur using solid carbon-based materials. Through a top hopper, a carbon-based material decomposition and SO2 deep reduction zone, an electrically heated auxiliary temperature control zone, and a slag cooling and heat recovery zone arranged sequentially from top to bottom, the carbon-based material is fed from the top of the reactor. As it moves downward, it continuously reduces SO2 and generates CO reducing gas. The SO2 raw material gas and part of the reflux COS gas enter from the bottom of the reactor. Through the auxiliary temperature control of the heating unit, the residual carbon in the bottom slag is fully reacted.

[0049] 3) The present technical solution provides a reactor and reaction system for promoting the reduction of SO2 to sulfur by solid carbon-based materials. By setting up a reactor and subsequent dust removal and cooling unit, SO2 reduction to Claus reaction unit and cooling unit, the product gas flowing out of the reactor from the top can be dusted and then converted to COS by downstream catalytic reaction. After that, it can react with newly added SO2 to undergo conventional Claus reaction, and finally obtain high-quality sulfur.

[0050] 4) This technical solution provides a reactor and reaction system for promoting the reduction of SO2 to sulfur using solid carbon-based materials. The reactor is equipped with a reflux gas inlet, and the product gas flowing out of the reactor from the top is further guided by a reflux fan. After dust removal, 10%-30% of the gas flow is recycled by the reflux fan after dust removal and cooling. The remaining gas flow is converted from COS to H2S through a downstream catalytic reaction, and then reacts with newly added SO2 in a conventional Claus reaction to finally obtain high-quality sulfur. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of a reaction system for promoting the reduction of SO2 to sulfur using solid carbon-based materials, as described in an embodiment of the present invention.

[0052] Figure 2 This is a schematic diagram of the electrically heated auxiliary temperature control zone of the reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials, as described in an embodiment of the present invention.

[0053] Figure 3 This is a schematic diagram of a reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials, as described in an embodiment of the present invention.

[0054] Numbering on the map:

[0055] 1: Top hopper; 1-1: Two-stage rotary valve; 2: Carbon-based material decomposition and SO2 deep reduction zone; 3: Electric heating auxiliary temperature control zone; 3-1: Electric heating element; 3-2: Heat storage shell; 3-1: Online slag scraping and slag loosening element; 4: Slag cooling and heat recovery zone; 5: Slag discharge outlet; 6: Water-sealed slag settling tank; 7: Bottom SO2 gas inlet of the reactor; 8: Top outlet of the reactor; 9: Recirculating gas inlet of the reactor; 10: Dust removal and cooling unit; 11: SO2 raw material gas; 12: SO2 reduction and conversion Claus reaction unit; 13: Cooling unit; 14: Sulfur product; 15: Catalytic hydrolysis unit; 16: Recirculating fan. Detailed Implementation

[0056] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0057] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0059] This invention proposes a reactor and reaction system for promoting the reduction of SO2 to sulfur using solid carbon-based materials, belonging to the field of sulfur resource utilization in metallurgy and energy environmental protection. Addressing the problems of excessively high reaction temperatures, difficult temperature control, and low sulfur quality resulting from the direct reduction of SO2 to sulfur using carbon-based reducing agents, this invention proposes a reduction reactor and reaction system with bottom electric heating to promote the gasification of carbon-based materials and the reduction of SO2. It utilizes a novel method of partially refluxing the intermediate product COS from SO2 reduction to promote SO2 reduction and carbon material gasification. The carbon-based material is fed from the top of the reactor, continuously reducing SO2 and generating CO reducing gas as it moves downwards. The SO2 feed gas and part of the refluxed COS gas enter from the bottom of the reactor, and the auxiliary temperature control of the heating unit (electrically heated auxiliary temperature control zone 3) promotes the full reaction of residual carbon in the bottom ash. The product gas flowing out of the reactor from the top is dedusted after dust removal, with 10%-30% of the gas stream being recycled by a reflux fan after further dust removal and cooling. The remaining gas stream undergoes a conventional Claus reaction with the newly added SO2 in a downstream catalytic reaction, ultimately yielding high-quality sulfur. This method and corresponding reaction system can significantly improve the yield and quality of sulfur production while reducing energy consumption, demonstrating promising application prospects.

[0060] The present invention will be further described in detail below with reference to specific embodiments.

[0061] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0062] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0063] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art. Unless otherwise specified, the functional components or structures are conventional components or conventional structures used in the art to achieve the corresponding functions.

[0064] Example 1

[0065] like Figures 1-3As shown, this embodiment provides a reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials. The reactor includes, from top to bottom, a top hopper 1, a carbon-based material decomposition and SO2 deep reduction zone 2, an electrically heated auxiliary temperature control zone 3, and a slag cooling and heat recovery zone 4. The top hopper 1 is used for quantitative feeding of carbon-based materials. The carbon-based material decomposition and SO2 deep reduction zone 2 is used to heat the carbon-based materials, so that the carbon-based materials are partially gasified and react with SO2 to deeply reduce SO2 to COS, while generating some excess CO reducing gas. The electrically heated auxiliary temperature control zone 3 is used to appropriately increase the reaction temperature to ensure that the remaining carbon-based materials react fully with SO2 at a higher temperature. The slag cooling and heat recovery zone 4 is used to cool the high-temperature slag generated after the reaction by contacting it with a low-temperature airflow, and to rapidly heat the SO2 gas to be reduced by direct contact with the high-temperature slag.

[0066] The top hopper 1, the carbon-based material decomposition and SO2 deep reduction zone 2, the electric heating auxiliary temperature control zone 3, and the slag cooling and heat recovery zone 4 are connected in sequence.

[0067] The reactor also includes a slag outlet 5, a bottom SO2 gas inlet 7, a top outlet 8, and a reflux gas inlet 9. The slag outlet 5 is located at the bottom of the reactor and is connected to a water-sealed slag tank 6 to discharge the high-temperature slag produced after the reaction. The bottom SO2 gas inlet 7 is located at the bottom of the reactor and allows the SO2 gas to be reduced to enter. The top outlet 8 is located at the top of the reactor and allows the gas produced after the reaction to flow out. The reflux gas inlet 9 is located in the middle of the reactor and allows the gas from the top outlet 8 to partially reflux after passing through the dust removal and cooling unit 10 for dust removal and cooling, thus promoting the reduction of SO2 and the gasification of carbon-based materials.

[0068] The reactor also includes a two-stage rotary valve 1-1; the two-stage rotary valve 1-1 is located between the top hopper 1 and the carbon-based material decomposition and SO2 deep reduction zone 2; the two-stage rotary valve 1-1 is used to prevent gas leakage while ensuring the solid carbon-based material.

[0069] The electric heating auxiliary temperature control zone 3 includes an electric heating element 3-1, a heat storage shell 3-2, and an online slag scraping and slag loosening element 3-3; the electric heating element 3-1 is connected to the heat storage shell 3-2; the online slag scraping and slag loosening element 3-3 is installed on the outer edge of the heat storage shell 3-2.

[0070] The heat storage shell 3-2 is a heat storage block with an electric heating element insertion hole for inserting an electric heating element 3-1; the height of the heat storage block is 300-600mm and the width is 40-100mm; multiple heat storage shells 3-2 are provided, and multiple heat storage blocks are arranged adjacent to each other; the gap between adjacent heat storage blocks is 50-200mm, and the high-temperature slag moves downward through the gap.

[0071] The online slag scraping and slag loosening element 3-3 includes a scraper blade with external teeth for loosening slag; the online slag scraping and slag loosening element 3-3 is a component made of heat-resistant metals such as 304H and 310s; the width of the online slag scraping and slag loosening element 3-3 is 40-60mm.

[0072] The reactor has a diameter of 1000-3000 mm and a height that is 3-5 times the diameter; the reactor is lined with heat-insulating material and has an external heat-insulating material.

[0073] The reactor includes a furnace chamber; the top hopper 1 is located at the top of the furnace chamber; the carbon-based material decomposition and SO2 deep reduction zone 2 is located in the upper middle part of the furnace chamber; the electric heating auxiliary temperature control zone 3 is located in the lower middle part of the furnace chamber; and the slag cooling and heat recovery zone 4 is located at the tail end of the furnace chamber.

[0074] An intermediate feeding section is provided between the top silo 1 and the carbon-based material decomposition and SO2 deep reduction zone 2. The two-stage rotary valve 1-1 is located on the intermediate feeding section between the top silo 1 and the carbon-based material decomposition and SO2 deep reduction zone 2. The diameter of the intermediate feeding section is smaller than the diameter of the top silo 1 and the diameter of the intermediate feeding section is smaller than the diameter of the carbon-based material decomposition and SO2 deep reduction zone 2.

[0075] The two-stage rotary valve 1-1 includes two rotary valves arranged sequentially from top to bottom.

[0076] The slag discharge outlet 5 is located at the bottom of the furnace chamber of the reactor.

[0077] The bottom SO2 gas inlet 7 of the reactor is located on the bottom side of the furnace chamber, and the position of the bottom SO2 gas inlet 7 of the reactor is higher than the position of the slag outlet 5.

[0078] The top outlet 8 of the reactor is located on the top side of the furnace chamber. The position of the top outlet 8 is lower than the position of the top hopper 1 and higher than the position of the carbon-based material decomposition and SO2 deep reduction zone 2.

[0079] The reflux gas inlet 9 of the reactor is located on the side of the middle part of the furnace chamber, and the position of the reflux gas inlet 9 of the reactor is higher than the position of the electric heating auxiliary temperature control zone 3.

[0080] Example 2

[0081] like Figures 1-3 As shown, this embodiment provides a reaction system, including the reaction furnace in Embodiment 1 that promotes the reduction of SO2 to sulfur using solid carbon-based materials.

[0082] The reaction system also includes a furnace for promoting the reduction of SO2 to sulfur using solid carbon-based materials. The system further includes a dust removal and cooling unit 10, a catalytic hydrolysis unit 15, an SO2 reduction-to-Claus reaction unit 12, and a cooling unit 13. The dust removal and cooling unit 10 is connected to the furnace via pipelines. The dust removal and cooling unit 10 is used to remove dust and cool the gas after the reaction. The catalytic hydrolysis unit 15 is connected to the dust removal and cooling unit 10 via pipelines. The catalytic hydrolysis unit 15 is used to catalytically hydrolyze the gas after dust removal and cooling. The SO2 reduction-to-Claus reaction unit 12 is connected to the catalytic hydrolysis unit 15 via pipelines. The SO2 reduction-to-Claus reaction unit 12 is used to react the catalytically hydrolyzed gas with the SO2 feed gas 11 to convert it into sulfur gas. The cooling unit 13 is connected to the SO2 reduction-to-Claus reaction unit 12 via pipelines. The cooling unit 13 is used to cool the sulfur gas to recover liquid or solid sulfur product 14.

[0083] The dust removal and cooling unit 10 can use conventional cyclone dust collectors, high-temperature ceramic filters, and other devices; the catalytic hydrolysis unit 15 is a catalytic hydrolysis reaction unit filled with an alumina-based catalytic filling layer, with a reaction temperature of 400-450℃; the SO2 reduction to Claus reaction unit 12 is a conventional alumina-based two-stage reaction device, with a reaction temperature of 180-350℃; and the cooling unit 13 is a two-stage condenser cooler unit.

[0084] The reaction system also includes a water-sealed slag tank 6; the water-sealed slag tank 6 is located below the reactor, the slag discharge outlet 5 is connected to the slag discharge outlet 5, and the slag discharge outlet 5 extends into the water-sealed slag tank 6.

[0085] The reaction system also includes a reflux fan 16, which is connected to the pipeline between the dust removal and cooling unit 10 and the catalytic hydrolysis unit 15 and the reflux gas inlet 9 of the reactor. Specifically, the inlet of the reflux fan 16 is connected to the pipeline between the dust removal and cooling unit 10 and the catalytic hydrolysis unit 15, and the outlet of the reflux fan 16 is connected to the reflux gas inlet 9 of the reactor.

[0086] The product gas flowing out of the reactor from the top, i.e. from the top outlet 8 of the reactor, is dedusted by the dust removal and cooling unit 10. After dust removal and cooling, 10%-30% of the gas flow is guided by the return fan 16 and enters the reactor for recycling through the return gas inlet 9 of the reactor.

[0087] Example 3

[0088] This embodiment provides an enhanced method for promoting the reduction of SO2 to sulfur using solid carbon-based materials. The enhanced method is implemented through the reaction system described in Example 2.

[0089] The enhancement method includes the following steps:

[0090] S1. Solid carbon-based material is metered into the upper part of the furnace, specifically the carbon-based material decomposition and SO2 deep reduction zone 2, from the top hopper 1 of the reactor via a two-stage rotary valve 1-1. The two-stage rotary valve 1-1 ensures solid material transport while preventing gas leakage. As the carbon-based material moves downwards, it is gradually heated and partially gasified in the decomposition and SO2 deep reduction zone 2, reacting with SO2 to deeply reduce SO2 to COS, while simultaneously generating some excess CO reducing gas. When the carbon-based material moves to the middle and lower parts of the reactor, the reaction temperature is appropriately increased via an electrically heated auxiliary temperature control zone 3 to ensure the remaining carbon-based material reacts fully with SO2 at a higher temperature. The resulting high-temperature slag is cooled in the slag cooling and heat recovery zone 4 by contact with a low-temperature airflow and discharged from the bottom slag outlet 5 into a water-sealed slag tank 6.

[0091] S2. The SO2 gas to be reduced enters from the SO2 gas inlet 7 at the bottom of the reactor. It is rapidly heated in the slag cooling and heat recovery zone 4 by direct contact with the high-temperature slag and rises to the electrically heated auxiliary temperature control zone 3. At a higher temperature, it undergoes a reduction reaction with the carbon-based materials and the CO produced by their gasification. The SO2 that is not fully reduced continues to flow upward and continues to react with the carbon-based materials in the middle and upper parts of the furnace, gradually transforming into COS.

[0092] S3. To promote the rapid reduction of SO2 and the gasification of carbon-based materials, the gas flow from the top outlet 8 of the reactor is partially refluxed after being filtered and cooled by the dust removal and cooling unit 10. It then enters the reactor through the reflux gas inlet 9, using reducing gases such as COS and CO to promote the low-temperature reduction of SO2 and the gasification of carbon materials, thereby significantly increasing the production load of the reactor.

[0093] S4. The gas flowing out from the top outlet 8 of the reactor is dusted and cooled by the dust removal and cooling unit 10. Its main components are COS, CO and CO2. Except for some recirculation, the remaining gas flow is catalytically hydrolyzed by the catalytic hydrolysis unit 15 and reacts with an appropriate amount of SO2 raw material gas 11. In the SO2 reduction and conversion Claus reaction unit 12, through a series of conventional Claus reactions between COS, CO and SO2, it is finally converted into high-purity sulfur gas. Then, the liquid or solid sulfur product 14 is recovered by the cooling unit 13.

[0094] The SO2 reduction reactor utilizes solid carbon-based materials such as coal and coke. It mainly includes the following units: top silo 1, carbon-based material decomposition and SO2 deep reduction zone 2, electric heating auxiliary temperature control zone 3, and slag cooling and heat recovery zone 4. Among them, the top silo 1 is the quantitative feeding silo for carbon-based materials at the top and the corresponding gas isolation unit; the middle and upper part of the furnace is the carbon-based material decomposition and SO2 deep reduction zone 2; the middle and lower part of the furnace is the electric heating auxiliary temperature control zone 3, which includes electric heating elements 3-1, heat storage shell 3-2, and online slag scraping and slag loosening elements 3-3; the tail end of the furnace is the slag cooling and heat recovery zone 4; and the bottom of the furnace is the slag discharge outlet 5, which is connected to the matching water-sealed slag settling tank 6.

[0095] The SO2 gas is high-concentration SO2 industrial flue gas, enriched and concentrated SO2 gas with a concentration of not less than 15%, an oxygen content of not more than 10%, and an optimal SO2 / O2 concentration ratio greater than 5. The SO2 gas to be reduced or the SO2 raw material gas 11 entering from the bottom SO2 gas inlet 7 of the reactor can be the SO2 gas mentioned above.

[0096] The carbon-based material is one or more of coke with low volatile content, activated carbon, and high-quality semi-coke. It is not easy to produce by-products such as tar during high-temperature reaction. The carbon-based material is granular with an equivalent particle diameter in the range of 5 to 50 mm.

[0097] The amount of carbon-based material conveyed from the top hopper 1 into the top of the furnace is achieved by adjusting the rotation speed of the two-stage rotary valve 1-1, and ensuring that no obvious air suction or leakage occurs between the reactor and the outside during the feeding process.

[0098] The electric heating auxiliary temperature control zone 3 of the reactor consists of a heat storage shell 3-2 (a heat storage block with insertion holes for electric heating elements), an online slag scraping and slag loosening element 3-3 installed on the outer edge of the heat storage block, and an electric heating element 3-1. The height of the heat storage block is 300-600 mm, and the width is 40-100 mm. The gap between the heat storage blocks is 50-200 mm, through which the char and slag move downwards. Through electric heating or heat storage, the temperature of the electric heating auxiliary temperature control zone 3 is maintained at 900-1100℃, ensuring sufficient reaction between SO2 and residual char in the high-temperature slag.

[0099] The online slag scraping and slag loosening elements 3-3 arranged on the outer edge of the heat storage block are made of heat-resistant metals such as 304H and 310s, with a width of 40-60mm. In addition to having sharp scraping blades, they also have external teeth for loosening slag. This prevents sticky slag from adhering to the surface of the heat storage block and affecting the heat exchange effect, while the external teeth loosen the relatively dense slag layer during their movement, increasing its permeability.

[0100] The reaction temperature in the upper part of the reactor, specifically the carbon-based material decomposition and SO2 deep reduction zone 2, is 600–900°C. The heat primarily originates from the exothermic reaction during SO2 reduction and the exothermic carbon oxidation generated by a small amount of oxygen in the gas stream. When the exothermic reaction is insufficient to maintain the required temperature, the electric heating element 3-1 in the lower heat storage block is activated to supplement energy.

[0101] The reactor has a diameter of 1000–3000 mm and a height 3–5 times its diameter. The reactor is lined with insulating material and supplemented with external heat-insulating material, specifically refractory bricks as the inner lining and insulation cotton as the outer layer. The apparent upward flow velocity of SO2, reflux gas, and other gases in the carbon layer is 0.05–0.2 m / s, and the total residence time of the carbon-based material in the reactor is 0.5–3 hours.

[0102] After the gas flow from the top outlet 8 of the reactor is cooled and dusted by the dust removal and cooling unit 10, a portion of it is recirculated. The recirculation rate accounts for 10-50% of the gas flow from the reactor. The COs and CO in the recirculated gas are used to promote the low-temperature reduction of SO2 and the gasification of carbon-based materials.

[0103] Example 4

[0104] This embodiment provides a reactor and intensification method for promoting the reduction of SO2 to sulfur using solid carbon-based materials. The reaction system of Example 2 is used to promote the reduction of SO2 to sulfur using coal-based coke. The specific steps are as follows:

[0105] The reaction furnace designed in Example 1 was selected as the reaction device. The furnace chamber is 3m high and 1m in diameter. The furnace is lined with heat-insulating material and externally with heat-insulating material, specifically refractory bricks as the inner lining and insulation cotton as the outer layer. The upper and middle reduction zone (the carbon-based material decomposition and SO2 deep reduction zone 2) accounts for approximately 60% of the total height of the effective volume area of ​​the furnace chamber (the effective volume area of ​​the furnace chamber refers to the area of ​​the carbon-based material decomposition and SO2 deep reduction zone 2, the electrically heated auxiliary temperature control zone 3, and the slag cooling and heat recovery zone 4). The remainder is the lower and middle electrically heated zone (electrically heated auxiliary temperature control zone 3) and the slag cooling and heat recovery zone 4. The reaction device includes a coke feed hopper (top hopper 1) with a capacity of 0.7m³. 3 It is equipped with an automatic quantitative sampling system (a conventional automatic quantitative sampling system; this invention does not modify the automatic quantitative sampling system), with a carbon particle injection rate of approximately 80 kg / h. The apparent upward flow velocity of gases such as SO2 and reflux gas in the carbon layer is approximately 0.1 m / s, and the flow rate of the SO2 inlet pipe (corresponding to the bottom SO2 gas inlet 7) is approximately 95 m³ / h. 3 / h.

[0106] The raw material used is coal coke with an equivalent particle size of approximately 20 mm. It enters the reactor from the top of the feed hopper 1 through a two-stage rotary valve 1-1, and from the upper part of the furnace. Simultaneously, SO2 gas enters the furnace through the inlet pipe and the bottom SO2 gas inlet 7. The reactor temperature is raised to 950 degrees Celsius by the electrically heated zone (electrically heated auxiliary temperature control zone 3) located in the middle and lower part of the furnace. At this point, SO2 reacts with the coke to produce CO2 and COS. The fully reduced SO2 continues to flow upwards, reacting with the carbon-based materials in the middle and upper parts of the furnace, gradually converting into COS. The SO2 conversion rate reaches 100%. The furnace outlet gas mainly contains CO2 and COS components. 20% of the gaseous products are returned to the lower part of the furnace via a reflux system (specifically: the product gas flowing out of the reactor from the top, i.e., from the top outlet 8 of the reactor, is dedusted and cooled by the dust removal and cooling unit 10, of which 20% is guided by the reflux fan 16 after dust removal and cooling, and then enters the reactor for recycling through the reflux gas inlet 9). The remaining gas, after dust removal and catalytic hydrolysis, enters the Claus process section of the subsequent SO2 reduction and conversion Claus reaction unit 12 to mix with SO2. The volume ratio of COS to the subsequently entering SO2 gas is 2:1. After the reaction, sulfur is produced by the cooling unit 13.

[0107] After the reflux gas enters the furnace, the refluxed COS component undergoes a pre-reduction reaction with the SO2 inlet gas. At this point, the furnace temperature is gradually reduced, with the temperature in the lower electric heating zone (electrically heated auxiliary temperature control zone 3) decreasing to 900℃. Here, CO2 and coke undergo a gasification reaction, with a CO to CO2 volume ratio of 2:8. The upper temperature is maintained at 800℃, and the SO2 conversion rate remains at 100%. All sulfur exists in the form of COS, which then enters the Claus process section of the Claus reaction unit 12 for SO2 reduction and conversion, mixing with SO2. This implementation successfully recovered solid sulfur products with a purity >99%.

[0108] Example 5

[0109] This embodiment provides a reactor and intensification method for promoting the reduction of SO2 to sulfur from solid carbon-based materials. The reaction system of Example 2 is used to promote the reduction of SO2 to sulfur from coal-based coke, which is basically the same as Example 4. The difference is that a new branch steam inlet is added at the inlet pipe of the reflux gas inlet 9, with a steam flow rate of approximately 120 kg / h. This embodiment utilizes the steam reforming reaction between steam and coke to generate H2. H2 and a portion of the steam then react with COS to undergo a hydrolysis reaction, generating H2S, which is more conducive to the Claus process and is subsequently recovered.

[0110] The temperature in the upper reduction zone (carbon-based material decomposition and SO2 deep reduction zone 2) of the furnace is 750℃, and the temperature in the lower electric heating zone (electric heating auxiliary temperature control zone 3) is 900℃. At this time, the product at the outlet contains H2, CO2, and H2S, with volume fractions of 10%, 30%, and 10%, respectively, and the remainder is N2. 20% of the gaseous product returns to the upper inlet of the furnace through the reflux system (specifically: the product gas flowing out of the reactor from the top, i.e., from the top outlet 8 of the reactor, is dedusted by the dust removal and cooling unit 10, and 20% of the gas flow is guided by the reflux fan 16 after dust removal and cooling, and enters the reactor for recycling through the reflux gas inlet 9 of the reactor). The remaining gas enters the Claus process section of the subsequent SO2 reduction and conversion Claus reaction unit 12 and mixes with SO2, where the volume ratio of H2S to SO2 gas is 2:1. After the reaction, sulfur product is generated through the cooling unit 13.

[0111] After the reflux gas reaches stability, the refluxed H2S undergoes a pre-reduction reaction with SO2. At this time, the furnace temperature is gradually reduced, and the upper temperature is gradually reduced to 700℃. The SO2 conversion rate is maintained at 100%, and the sulfur element mainly exists in the form of H2S. Subsequently, it enters the Claus process section of the Claus reaction unit 12 for SO2 reduction and conversion and mixes with SO2, successfully recovering solid sulfur products with a purity >99%.

[0112] Example 6

[0113] This embodiment provides a reactor and enhancement method for promoting the reduction of SO2 to sulfur using solid carbon-based materials. The reaction system of Example 2 is used to promote the reduction of SO2 to sulfur using coal-based coke, which is basically the same as Example 4. The difference is that the carbon-based raw material is replaced with corn straw biomass with an equivalent particle size of about 20 mm. In addition to the SO2 reduction reaction, a biomass thermal dehydrogenation reaction also occurs in the upper part of the furnace. The generated H2 is further used for SO2 reduction.

[0114] The temperature in the upper reduction zone (carbon-based material decomposition and SO2 deep reduction zone 2) of the furnace is 800℃, and the temperature in the lower electric heating zone (electric heating auxiliary temperature control zone 3) is 950℃. Biomass pyrolysis also produces some tar components, which react with the remaining SO2 in the lower part to generate CO2. At this time, the product at the outlet contains H2, CO2, and H2S, with volume fractions of 5%, 45%, and 5%, respectively, and the remainder is N2. 20% of the gaseous products are returned to the upper inlet of the furnace via a reflux system (specifically: the product gas flowing out of the reactor from the top, i.e., from the top outlet 8 of the reactor, is dedusted by the dust removal and cooling unit 10, and 20% of the gas flow is guided by the reflux fan 16 after dust removal and cooling, and enters the reactor for recycling through the reflux gas inlet 9 of the reactor). The remaining gas enters the Claus process section of the subsequent SO2 reduction and conversion Claus reaction unit 12 and mixes with SO2, wherein the volume ratio of H2S to SO2 gas is 2:1. After the reaction, sulfur is generated by the cooling unit 13.

[0115] After the reflux gas reaches stability, the refluxed H2S undergoes a pre-reduction reaction with SO2. At this time, the furnace temperature is gradually reduced, with the upper temperature gradually decreasing to 650℃ and the middle and lower electric heating zone (electric heating auxiliary temperature control zone 3) maintained at around 900℃. The SO2 conversion rate is maintained at 100%, and the sulfur element mainly exists in the form of H2S. Subsequently, it enters the Claus process section of the SO2 reduction and conversion Claus reaction unit 12 and mixes with SO2, successfully recovering solid sulfur products with a purity >99%.

[0116] Example 7

[0117] This embodiment provides a reactor and enhancement method for promoting the reduction of SO2 to sulfur using solid carbon-based materials. The reaction system of Example 2 is used to promote the reduction of SO2 to sulfur using coal-based coke, which is basically the same as Example 4. The difference is that the carbon-based raw material is replaced with corn straw biomass, with an equivalent particle size of approximately 20 mm. Furthermore, a new branch steam inlet is installed at the inlet pipe of the reflux gas inlet (9), with a steam flow rate of approximately 120 kg / h. Sulfur is prepared through the coupling of the biomass pyrolysis dehydrogenation process and water vaporization.

[0118] The temperature in the upper reduction zone (carbon-based material decomposition and SO2 deep reduction zone 2) of the furnace is 700℃, and the temperature in the lower electric heating zone (electric heating auxiliary temperature control zone 3) is 950℃. At this time, the product at the outlet contains H2, CO2, and H2S, with volume fractions of 25%, 30%, and 10%, respectively, and the remainder is N2. 20% of the gaseous product returns to the upper inlet of the furnace through the reflux system (specifically: the product gas flowing out of the reactor from the top, i.e., from the top outlet 8 of the reactor, is dedusted by the dust removal and cooling unit 10, and 20% of the gas flow is guided by the reflux fan 16 after dust removal and cooling, and enters the reactor for recycling through the reflux gas inlet 9 of the reactor). The remaining gas enters the Claus process section of the subsequent SO2 reduction and conversion Claus reaction unit 12 and mixes with SO2, where the volume ratio of H2S to SO2 gas is 2:1. After the reaction, sulfur is generated by the cooling unit 13 and collected.

[0119] After the reflux gas reaches stability, the refluxed H2S undergoes a pre-reduction reaction with SO2. At this time, the furnace temperature is gradually reduced, with the upper temperature gradually decreasing to 600℃ and the temperature of the middle and lower electric heating zone (electric heating auxiliary temperature control zone 3) decreasing to 900℃. The SO2 conversion rate is maintained at 100%, and the sulfur element mainly exists in the form of H2S. Subsequently, it still enters the Claus process section of the SO2 reduction and conversion Claus reaction unit 12 to mix with SO2, and successfully recovers solid sulfur products with a purity >99%.

[0120] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials, characterized in that, The reactor includes, from top to bottom, a top hopper (1), a carbon-based material decomposition and SO2 deep reduction zone (2), an electric heating auxiliary temperature control zone (3), and a slag cooling and heat recovery zone (4); The top hopper (1) is used for feeding carbon-based materials; The carbon-based material decomposition and SO2 deep reduction zone (2) is used to heat the carbon-based material, so that the carbon-based material is partially gasified and reacts with SO2 to deeply reduce SO2 to COS, while generating CO reduction gas. The electric heating-assisted temperature control zone (3) is used to increase the reaction temperature and ensure that the remaining carbon-based materials react fully with SO2 at a higher temperature; The slag cooling and heat recovery zone (4) is used to cool the high-temperature slag produced after the reaction by contacting it with a low-temperature airflow, and to heat the SO2 gas to be reduced by directly contacting it with the high-temperature slag.

2. The reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials according to claim 1, characterized in that, The reactor also includes a slag outlet (5), a bottom SO2 gas inlet (7), a top outlet (8), and a reflux gas inlet (9). The slag discharge outlet (5) is located at the bottom of the reactor; The slag outlet (5) is used to connect with the matching water-sealed slag tank (6) to discharge the high-temperature slag generated after the reaction from the reactor. The SO2 gas inlet (7) at the bottom of the reactor is located at the bottom of the reactor; The SO2 gas inlet (7) at the bottom of the reactor is used to allow the SO2 gas to be reduced to enter; The top outlet (8) of the reactor is located at the top of the reactor; The top outlet (8) of the reactor is used to discharge the gas after the reaction; The reflux gas inlet (9) of the reactor is located in the middle of the reactor; The reflux gas inlet (9) of the reactor is used to partially reflux the gas flow from the top outlet (8) of the reactor after it has been cooled and dusted, thereby promoting the reduction of SO2 and the gasification of carbon-based materials.

3. The reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials according to claim 1, characterized in that, The reactor also includes a two-stage rotary valve (1-1); The two-stage rotary valve (1-1) is located between the top hopper (1) and the carbon-based material decomposition and SO2 deep reduction zone (2); The two-stage rotary valve (1-1) is used to prevent gas leakage while ensuring the solid carbon-based material.

4. The reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials according to claim 1, characterized in that, The electric heating auxiliary temperature control zone (3) includes an electric heating element (3-1), a heat storage shell (3-2), and an online slag scraping and slag loosening element (3-3); The electric heating element (3-1) is connected to the heat storage shell (3-2); The online slag scraping and slag loosening element (3-3) is installed on the outer edge of the heat storage shell (3-2).

5. A reaction furnace for promoting the reduction of SO2 to sulfur using solid carbon-based materials according to claim 4, characterized in that, The heat storage shell (3-2) is a heat storage block with an electric heating element insertion hole, which is used to insert an electric heating element (3-1); The height of the heat storage block is 300-600 mm, and the width is 40-100 mm; Multiple heat storage shells (3-2) are provided, and multiple heat storage blocks are arranged adjacent to each other; The gap between adjacent heat storage blocks is 50-200mm, and the high-temperature slag moves downward through the gap.

6. The reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials according to claim 4, characterized in that, The online slag scraping and slag loosening element (3-3) includes a slag scraper blade with external teeth for loosening slag. The online slag scraping and slag loosening element (3-3) is a component made of heat-resistant metal; The width of the online slag scraping and slag loosening element (3-3) is 40-60 mm.

7. The reactor for promoting the reduction of SO2 to sulfur using solid carbon-based materials according to claim 1, characterized in that, The reactor has a diameter of 1000-3000 mm and a height that is 3-5 times its diameter. The reactor is lined with heat-insulating material and externally with heat-insulating material.

8. A reaction system comprising a reactor as described in any one of claims 1-7, characterized in that, The reaction system also includes a dust removal and cooling unit (10), a catalytic hydrolysis unit (15), a SO2 reduction and conversion Claus reaction unit (12), and a cooling unit (13); The dust removal and cooling unit (10) is connected to the reactor; The dust removal and cooling unit (10) is used to remove dust and cool the gas after the reaction; The catalytic hydrolysis unit (15) is connected to the dust removal and cooling unit (10); The catalytic hydrolysis unit (15) is used to catalytically hydrolyze the gas after dust removal and cooling; The SO2 reduction and conversion Claus reaction unit (12) is connected to the catalytic hydrolysis unit (15); The SO2 reduction and conversion Claus reaction unit (12) is used to convert the gas after catalytic hydrolysis into sulfur gas by reacting with the SO2 raw material gas (11). The cooling unit (13) is connected to the SO2 reduction and conversion Claus reaction unit (12); The cooling unit (13) is used to cool sulfur gas to recover liquid or solid sulfur products (14).

9. A reaction system according to claim 8, characterized in that, The reaction system also includes a water-sealed sedimentation tank (6); The water-sealed sedimentation tank (6) is located below the reactor.

10. An enhanced method for promoting the reduction of SO2 to sulfur using solid carbon-based materials, characterized in that, The enhancement method, implemented via the reaction system as described in claim 8, comprises the following steps: S1. Solid carbon-based materials enter the upper part of the furnace from the top hopper (1) of the reactor, that is, the carbon-based material decomposition and SO2 deep reduction zone (2). As the carbon-based materials move downward, they are gradually heated and partially gasified in the carbon-based material decomposition and SO2 deep reduction zone (2) and react with SO2 to deeply reduce SO2 to COS. At the same time, some excess CO reducing gas is generated. When the carbon-based materials move down to the middle and lower part of the reactor, the reaction temperature will be increased by the electric heating auxiliary temperature control zone (3) to ensure that the remaining carbon-based materials react fully with SO2 at a higher temperature. The high-temperature slag generated after the reaction is cooled down by contacting the low-temperature airflow in the slag cooling and heat recovery zone (4) and discharged from the reactor. S2, SO2 gas to be reduced enters from the bottom of the reactor and is heated by direct contact with high-temperature slag in the slag cooling and heat recovery zone (4), and rises to the electric heating auxiliary temperature control zone (3), where it undergoes a reduction reaction with carbon-based materials and CO produced by their gasification at a higher temperature; the SO2 that is not fully reduced continues to flow upward and continues to react with carbon-based materials in the middle and upper parts of the furnace, gradually transforming into COS; S3. After the gas flowing out from the top of the reactor is removed and cooled by the dust removal and cooling unit (10), its main components are COS, CO and CO2. After being catalytically hydrolyzed by the catalytic hydrolysis unit (15), it reacts with SO2 raw material gas (11). In the SO2 reduction and conversion Claus reaction unit (12), through a series of reduction and conversion Claus reactions between COS, CO and SO2, it is finally converted into high-purity sulfur gas. Then, through the cooling unit (13), liquid or solid sulfur products (14) are recovered.

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