SO2 reduction furnace, sulfur recovery system and recovery method

Abstract

The present application relates to a kind of SO2 reduction furnace, sulfur recovery system and recovery method.The SO2 reduction furnace includes reduction furnace body, gas inlet and gas outlet are equipped on the reduction furnace body;The reduction furnace body includes storage area, high-temperature pyrolysis reduction zone and cooling recovery zone from top to bottom in sequence, auxiliary heating component is equipped in high-temperature pyrolysis reduction zone;The top of the reduction furnace body is equipped with first feeding channel and the second feeding channel concentrically arranged in first feeding channel;Wherein, first feeding channel is inserted into storage area and is communicated with high-temperature pyrolysis reduction zone, second feeding channel is communicated with high-temperature pyrolysis reduction zone and is threaded through first feeding channel.The first feeding channel is used for quantitatively conveying low-volatility auxiliary reduction material, and the second feeding channel is used for quantitatively conveying high-volatility carbon-based material.Compared with prior art, the present application can effectively reduce the generation of tar in SO2 reduction process and improve the yield and quality of sulfur.

Description

Technical Field

[0001] This invention relates to the field of SO2 reduction technology, and in particular to an SO2 reduction furnace, a sulfur recovery system and a recovery method. Background Technology

[0002] SO2 is one of the most widespread and abundant gaseous pollutants in industries such as coal combustion and non-ferrous metals. Improper treatment can cause serious environmental pollution. Traditional treatment methods involve converting SO2 into gypsum using dry or wet lime processes. However, desulfurized gypsum is of poor quality and low value, and the accumulation of large amounts of desulfurized gypsum can cause secondary pollution. Therefore, it is necessary to develop new SO2 treatment technologies.

[0003] SO2 reduction and conversion is a promising resource utilization method. By reacting SO2 with a reducing agent, it is converted into elemental sulfur, which is not only easy to store and transport but also has high application value. Reducing SO2 using biomass is a novel SO2 reduction technology. Compared to traditional reducing agents such as CH4, H2, and CO, biomass has advantages such as wide availability and low cost. Furthermore, biomass has a high volatile content and will spontaneously pyrolyze at high temperatures, producing reducing gases. These reducing gases contain components such as H2, alkanes, and alkenes, which can reduce SO2 at relatively low temperatures, thus enhancing the SO2 reduction capacity of biomass. However, unreacted reducing organic gases are prone to condensation when entering downstream, causing pipeline blockage and equipment corrosion. The resulting tar accumulation is currently the biggest drawback and limiting factor in biomass utilization.

[0004] Patent CN119220276A discloses a low-tar biomass gasification furnace and its usage method. Specifically, it uses a movable plate on the side of the gasification furnace, a spray nozzle, and a valve to add filter media to adsorb and discharge tar. This method provides a way to reduce tar damage, but tar production is not effectively suppressed, and long-term use still causes corrosion to the filter components. Patent CN119240611A discloses a method for the fractional utilization of tar-hydrogen co-production, aiming to separate the tar generated during the pyrolysis and gasification of organic solid waste into light, medium, and heavy tar based on differences in boiling range through in-situ hot fractionation, facilitating utilization. However, the problem of tar damage in the pipeline remains unresolved.

[0005] Therefore, how to suppress the generation and accumulation of tar during the thermal conversion and reduction of SO2 from biomass remains a technical challenge that urgently needs to be addressed. Summary of the Invention

[0006] The purpose of this invention is to provide an SO2 reduction furnace, a sulfur recovery system, and a recovery method to suppress the generation and accumulation of tar during biomass thermal conversion.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] The present invention first provides an SO2 reduction furnace, including a reduction furnace body, wherein the bottom of the reduction furnace body is provided with a gas inlet for introducing SO2 mixed gas, and the top of the reduction furnace body is provided with a gas outlet; the reduction furnace body includes, from top to bottom, a material storage area, a high-temperature pyrolysis reduction area and a cooling recovery area, wherein the high-temperature pyrolysis reduction area is provided with an auxiliary heating component.

[0009] The top of the reduction furnace body is provided with a first feeding channel and a second feeding channel concentrically arranged within the first feeding channel; wherein, the first feeding channel extends into the storage area and communicates with the high-temperature pyrolysis reduction zone, and the second feeding channel passes through the first feeding channel and communicates with the high-temperature pyrolysis reduction zone;

[0010] The top of the first feeding channel is connected to a first quantitative feeding hopper for quantitatively conveying low-volatility auxiliary reducing materials; the top of the second feeding channel is connected to a second quantitative feeding hopper for quantitatively conveying high-volatility carbon-based materials.

[0011] Furthermore, the diameter of the reduction furnace body is 1000-4000mm.

[0012] Furthermore, the height of the reduction furnace body is 3-6 times its diameter.

[0013] Furthermore, the reduction furnace body is lined with heat-insulating material and supplemented with external heat-insulating material.

[0014] Furthermore, the bottom of the cooling recovery zone is a slag discharge outlet.

[0015] Furthermore, the slag discharge outlet is connected to a water-sealed sedimentation tank.

[0016] Furthermore, both the first and second quantitative feed hoppers are equipped with two-stage rotary valves.

[0017] Furthermore, the auxiliary heating assembly includes a heat storage shell, an electric heating element disposed within the heat storage shell, and an online slag scraping and slag loosening element installed on the outer edge of the heat storage shell.

[0018] Furthermore, the temperature of the storage area is 600-900℃.

[0019] Furthermore, the temperature of the high-temperature pyrolysis reduction zone is 900-1100℃.

[0020] Furthermore, a reflux gas inlet is provided on the reduction furnace body corresponding to the high-temperature pyrolysis reduction zone.

[0021] Furthermore, the gas output from the gas outlet is cooled and dust removed before flowing back to the return gas inlet, and the return flow rate of the return gas accounts for 10-30% of the gas outflow from the reduction furnace body.

[0022] Furthermore, the low-volatile auxiliary reducing materials include one or more of coke, activated carbon, and high-quality semi-coke.

[0023] Furthermore, the highly volatile carbon-based material includes one or more of biomass, coal, waste rubber, and low-quality semi-coke.

[0024] Furthermore, both the auxiliary reducing material and the carbon-based material are granular, with an equivalent particle diameter of 5-50 mm.

[0025] Furthermore, the total residence time of the auxiliary reducing materials and carbon-based materials in the reduction furnace body is 0.5 to 3.5 hours.

[0026] Furthermore, the concentration of SO2 in the mixed gas introduced through the gas inlet is not less than 15%, the content of O2 is not more than 10%, and the SO2 / O2 concentration ratio is greater than 5.

[0027] Furthermore, the apparent upward flow velocity of the gas within the reduction furnace body is 0.05–0.25 m / s.

[0028] The present invention also provides a sulfur recovery system including the SO2 reduction furnace, wherein the sulfur recovery system further includes a dust removal and cooling unit, a catalytic hydrolysis unit, a Claus reaction unit and a cooling unit connected in sequence to the reduction furnace body.

[0029] Furthermore, the sulfur recovery system also includes a return fan.

[0030] Furthermore, the gas inlet of the reflux fan is connected to the dust removal and cooling unit, and the gas outlet is connected to the reduction furnace body.

[0031] The present invention also provides a sulfur recovery method using a sulfur recovery system, the sulfur recovery method comprising the following steps:

[0032] S1: Low-volatility auxiliary reducing material and high-volatility carbon-based material are added through the first feeding channel and the second feeding channel respectively, so that the two are mixed and gasified in the high-temperature pyrolysis reduction zone to generate CO;

[0033] S2: The gas to be reduced, containing SO2, is introduced into the gas inlet. The gas undergoes a reduction reaction with CO in the high-temperature pyrolysis reduction zone.

[0034] S3: The gas after the reaction is output from the gas outlet, passes through the dust removal and cooling unit and the catalytic hydrolysis unit, and then reacts with SO2. After reacting in the Claus reaction unit, it is converted into high-purity sulfur gas, and finally recovers the sulfur product through the cooling unit.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The SO2 reduction furnace of the present invention adopts a first feeding channel and a second feeding channel arranged concentrically to feed the auxiliary reducing material and the main reducing material in separate zones, so that the carbon-based material that is prone to producing tar by-products can be directly fed into the high-temperature pyrolysis reduction zone of the SO2 reduction furnace to effectively prevent the generation of tar.

[0037] (2) This invention fully considers the performance differences between low-volatility auxiliary reducing materials and high-volatility carbon-based materials, and feeds the two types of carbon-based materials in separate sections. The high-volatility carbon-based material is directly fed into the high-temperature pyrolysis reduction zone through the second feeding channel and is fully pyrolyzed and gasified there, effectively avoiding the generation of tar byproducts. The low-volatility auxiliary reducing material, after being fed into the storage area through the first feeding channel, slowly moves downwards into the high-temperature pyrolysis reduction zone during gasification and SO2 reduction until it mixes with the high-volatility carbon-based material in the high-temperature pyrolysis reduction zone and is fully pyrolyzed and gasified together.

[0038] (3) The SO2 reduction furnace of the present invention is configured with targeted partitions and auxiliary heating components are set in the high-temperature pyrolysis reduction zone to adjust the gasification temperature of the high-temperature section.

[0039] (4) The present invention can also utilize the COS intermediate product of SO2 reduction to partially reflux, further promote the low-temperature reduction of SO2 and avoid the generation of tar. The tar content can be reduced to 0.002 g / g biomass or even none, thereby improving the yield and quality of sulfur.

[0040] (5) The sulfur recovery system of the present invention adopts an SO2 reduction furnace and combines it with reflux and Claus reaction units, which can significantly improve the yield and quality of sulfur production, and reduce the energy consumption and cost of sulfur production, and has good application prospects. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the SO2 reduction furnace of the present invention.

[0042] Figure 2 This is a schematic diagram of the auxiliary heating component of the SO2 reduction furnace of the present invention.

[0043] Figure 3 This is a schematic diagram of the sulfur recovery system of Embodiment 2 of the present invention.

[0044] Figure 4 This is a schematic diagram of the sulfur recovery system of Embodiment 3 of the present invention.

[0045] Explanation of markings in the diagram:

[0046] 1-Reduction furnace body, 11-Gas inlet, 12-Gas outlet, 13-Storage area, 14-High temperature pyrolysis reduction zone, 15-Cooling recovery zone, 151-Slag discharge outlet, 152-Water-sealed slag settling tank, 16-Auxiliary heating components, 161-Heat storage shell, 162-Electric heating element, 163-Online slag scraping and slag loosening element, 17-Reflux gas inlet;

[0047] 2-First feeding channel; 21-First quantitative feeding hopper;

[0048] 3-Second feeding channel; 31-Second quantitative feeding hopper;

[0049] 4-Two-stage rotary valve;

[0050] 5-Dust removal and cooling unit;

[0051] 6-Catalytic hydrolysis unit;

[0052] 7-Claus reaction unit;

[0053] 8-Cooling unit;

[0054] 9-Return fan. Detailed Implementation

[0055] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0056] In this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention; the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, or integral connections; they can be mechanical connections or electrical connections; they can be direct connections or indirect connections through an intermediate medium; they can be internal connections between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0057] 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.

[0058] To address the technical problem that conventional carbon-based materials containing high volatile matter are prone to producing tar during the SO2 reduction process, this invention first provides an SO2 reduction furnace that can greatly reduce tar production during SO2 reduction.

[0059] The SO2 reduction furnace of the present invention includes a furnace body 1. The furnace body 1 has a gas inlet 11 at its bottom for introducing a SO2-containing mixed gas, and a gas outlet 12 at its top. The furnace body 1, from top to bottom, includes a storage area 13, a high-temperature pyrolysis reduction area 14, and a cooling and recovery area 15. An auxiliary heating component 16 is provided within the high-temperature pyrolysis reduction area 14. The top of the furnace body 1 has a first feeding channel 2 and a second feeding channel 3 concentrically arranged within the first feeding channel 2. The first feeding channel 2 extends into the storage area 13 and communicates with the high-temperature pyrolysis reduction area 14, while the second feeding channel 3 penetrates the first feeding channel 2 and communicates with the high-temperature pyrolysis reduction area 14. A first quantitative feed hopper 21 is connected to the top of the first feeding channel 2 for quantitatively conveying low-volatility auxiliary reducing materials; a second quantitative feed hopper 31 is connected to the top of the second feeding channel 3 for quantitatively conveying high-volatility carbon-based materials.

[0060] In some specific embodiments, the diameter of the reduction furnace body 1 is 1000-4000 mm.

[0061] In some specific embodiments, the height of the reduction furnace body 1 is 3-6 times its diameter.

[0062] In some specific embodiments, the reduction furnace body 1 is lined with heat-insulating material and externally insulated.

[0063] In some specific embodiments, the bottom of the cooling recovery zone 15 is a slag discharge outlet 151.

[0064] In some specific embodiments, the slag discharge outlet 151 is connected to the water-sealed sedimentation tank 152.

[0065] In some specific embodiments, both the first quantitative feed hopper 21 and the second quantitative feed hopper 31 are equipped with a secondary rotary valve 4. The amount of low-volatility or high-volatility carbon-based material conveyed from the hopper to the top of the furnace is achieved by adjusting the rotation speed of the secondary rotary valve 4, ensuring that no significant air suction or leakage occurs between the reactor and the outside environment during the feeding process.

[0066] In some specific embodiments, the auxiliary heating assembly 16 includes a heat storage shell 161, an electric heating element 162 disposed inside the heat storage shell 161, and an online slag scraping and slag loosening element 163 installed on the outer edge of the heat storage shell 161.

[0067] In addition to having a sharper scraper blade, the online slag scraping and slag loosening element 163 also has external teeth for loosening slag, which can prevent sticky slag from adhering to the surface of the heat storage shell 161 and affecting the heat exchange effect; the external teeth loosen the relatively dense slag layer during its movement, increasing its air permeability.

[0068] In some specific embodiments, the temperature of the high-temperature pyrolysis reduction zone 14 is 900-1100℃. The high-temperature pyrolysis reduction zone 14 is maintained at 900-1100℃ by the electric heating or heat storage effect of the auxiliary heating component 16, ensuring sufficient reaction between SO2 and residual carbon in the slag.

[0069] In some specific embodiments, the temperature of the storage zone 13 is 600-900°C.

[0070] In some specific embodiments, a reflux gas inlet 17 is provided on the reduction furnace body 1 corresponding to the high-temperature pyrolysis reduction zone 14.

[0071] In some specific embodiments, the gas output from the gas outlet 12 is cooled by the dust removal and cooling unit 5 and then returned to the return gas inlet 17 by the return fan 9. The return flow rate of the return gas accounts for 10 to 30% of the gas outflow of the reduction furnace body 1.

[0072] In some specific embodiments, the low-volatility auxiliary reducing material includes one or more of coke, activated carbon, and high-quality semi-coke.

[0073] In some specific embodiments, the highly volatile carbon-based material includes one or more of biomass, coal, waste rubber, and low-quality semi-coke.

[0074] In some specific embodiments, both the auxiliary reducing material and the carbon-based material are in particulate form, and the equivalent diameter of the particles is 5-50 mm.

[0075] In some specific embodiments, the total residence time of the auxiliary reducing material and the carbon-based material in the reduction furnace body 1 is 0.5 to 3.5 hours.

[0076] In some specific embodiments, the concentration of SO2 in the mixed gas introduced through the gas inlet 11 is not less than 15%, the content of O2 is not more than 10%, and the SO2 / O2 concentration ratio is greater than 5.

[0077] In some specific embodiments, the apparent upward flow velocity of the gas within the reduction furnace body 1 is 0.05–0.25 m / s.

[0078] To recover sulfur using the aforementioned SO2 reduction furnace device, the present invention also provides a sulfur recovery system and a sulfur recovery method using the sulfur recovery system. The sulfur recovery system includes a reduction furnace body 1, and further includes a dust removal and cooling unit 5, a catalytic hydrolysis unit 6, a Claus reaction unit 7, and a cooling unit 8 connected in sequence to the reduction furnace body 1.

[0079] In some specific embodiments, the sulfur recovery system further includes a reflux fan 9. The gas inlet of the reflux fan 9 is connected to the dust removal and cooling unit 5, and the gas outlet is connected to the reduction furnace body 1.

[0080] The sulfur recovery method of the present invention specifically includes the following steps:

[0081] S1: Low-volatility auxiliary reducing material and high-volatility carbon-based material are added through the first feeding channel 2 and the second feeding channel 3 respectively, so that the two are mixed and gasified in the high-temperature pyrolysis reduction zone 14 to generate CO;

[0082] S2: The gas to be reduced, containing SO2, is introduced into the gas inlet 11. The gas undergoes a reduction reaction with CO in the high-temperature pyrolysis reduction zone 14.

[0083] S3: The gas after the reaction is output from gas outlet 12, and after passing through dust removal and cooling unit 5 and catalytic hydrolysis unit 6, it reacts with SO2 and is converted into high-purity sulfur gas after being reacted by Claus reaction unit 7. Finally, it is recovered by cooling unit 8 to obtain sulfur product.

[0084] Each of the above embodiments can be implemented individually, or in any combination of two or more. The following detailed description of specific examples will further illustrate these embodiments.

[0085] Example 1:

[0086] This embodiment provides an SO2 reduction furnace. For example... Figure 1 As shown, the SO2 reduction furnace of this embodiment includes a reduction furnace body 1. The bottom of the reduction furnace body 1 is provided with a gas inlet 11 for introducing SO2 mixed gas, and the top of the reduction furnace body 1 is provided with a gas outlet 12.

[0087] The reduction furnace body 1 in this embodiment includes, from top to bottom, a material storage area 13, a high-temperature pyrolysis reduction area 14, and a cooling recovery area 15. The high-temperature pyrolysis reduction area 14 is equipped with an auxiliary heating component 16, which is used to adjust and maintain the high temperature required for pyrolysis reduction.

[0088] To suppress tar generation during the reduction of SO2 by carbon-based materials, the top of the reduction furnace body 1 is provided with a first feeding channel 2 and a second feeding channel 3 concentrically arranged within the first feeding channel 2. The first feeding channel 2 extends into the storage area 13 and communicates with the high-temperature pyrolysis reduction zone 14, while the second feeding channel 3 penetrates the first feeding channel 2 and communicates with the high-temperature pyrolysis reduction zone 14. The top of the first feeding channel 2 is connected to a first quantitative feed hopper 21 for quantitatively conveying low-volatility auxiliary reducing materials; the top of the second feeding channel 3 is connected to a second quantitative feed hopper 31 for quantitatively conveying high-volatility carbon-based materials.

[0089] This embodiment fully considers the performance differences between low-volatility auxiliary reducing materials and high-volatility carbon-based materials. Therefore, it sets up a first feeding channel 2 and a second feeding channel 3 to feed the two types of carbon-based materials in separate sections. The high-volatility carbon-based material is directly fed into the high-temperature pyrolysis reduction zone 14 through the second feeding channel 3 and is fully pyrolyzed and gasified in the high-temperature pyrolysis reduction zone 14, thereby effectively avoiding the generation of tar byproducts. The low-volatility auxiliary reducing material is fed into the storage zone 13 through the first feeding channel 2 and slowly moves down into the high-temperature pyrolysis reduction zone 14 during the gasification and SO2 reduction process until it mixes with the high-volatility carbon-based material in the high-temperature pyrolysis reduction zone 14 and is fully pyrolyzed and gasified together.

[0090] Example 2:

[0091] This embodiment provides an SO2 reduction furnace and a sulfur recovery system including the SO2 reduction furnace.

[0092] The SO2 reduction furnace of this embodiment includes a reduction furnace body 1. The diameter of the reduction furnace body 1 in this embodiment is 1000-4000 mm, and the height of the reduction furnace body 1 is 3-6 times its diameter. The reduction furnace body 1 is lined with heat-insulating material and covered with heat-insulating material.

[0093] In this embodiment, the reduction furnace body 1 has a gas inlet 11 at the bottom for introducing SO2-containing mixed gas, and a gas outlet 12 at the top. The reduction furnace body 1 includes, from top to bottom, a material storage area 13, a high-temperature pyrolysis reduction area 14, and a cooling and recovery area 15. An auxiliary heating assembly 16 is provided in the high-temperature pyrolysis reduction area 14. The bottom of the cooling and recovery area 15 is a slag discharge outlet 151, which is connected to a matching water-sealed sedimentation tank 152.

[0094] The auxiliary heating component 16 in this embodiment is as follows: Figure 2 As shown, it specifically includes a heat storage shell 161, an electric heating element 162 disposed inside the heat storage shell 161, and an online slag scraping and slag loosening element 163 installed on the outer edge of the heat storage shell 161. In addition to having sharp scraping blades, the online slag scraping and slag loosening element 163 also has external teeth for loosening slag, thus preventing sticky slag from adhering to the surface of the heat storage shell 161 and affecting the heat exchange effect; the external teeth, during their movement, loosen the relatively dense slag layer, increasing its permeability.

[0095] In this embodiment, the reduction furnace body 1 has a first feeding channel 2 and a second feeding channel 3 concentrically arranged within the first feeding channel 2. The first feeding channel 2 extends into the storage area 13 and communicates with the high-temperature pyrolysis reduction zone 14, while the second feeding channel 3 penetrates the first feeding channel 2 and communicates with the high-temperature pyrolysis reduction zone 14. The top of the first feeding channel 2 is connected to a first quantitative feed hopper 21 for quantitatively conveying low-volatility auxiliary reducing materials; the top of the second feeding channel 3 is connected to a second quantitative feed hopper 31 for quantitatively conveying high-volatility carbon-based materials.

[0096] In this embodiment, both the first quantitative feed hopper 21 and the second quantitative feed hopper 31 are equipped with a secondary rotary valve 4. The amount of low-volatility or high-volatility carbon-based material conveyed from the hopper into the top of the furnace is achieved by adjusting the rotation speed of the secondary rotary valve 4, ensuring that no significant air suction or leakage occurs between the reactor and the outside environment during the feeding process.

[0097] like Figure 3As shown, the sulfur recovery system of this embodiment includes a reduction furnace body 1, and further includes a dust removal and cooling unit 5, a catalytic hydrolysis unit 6, a Claus reaction unit 7, and a cooling unit 8 connected in sequence to the reduction furnace body 1. The dust removal and cooling unit 5 can use conventional cyclone dust collectors, high-temperature ceramic filters, etc.; the catalytic hydrolysis unit 6 is a catalytic hydrolysis reaction unit filled with an alumina-based catalytic packing layer, with a reaction temperature of 400-450℃; the Claus reaction unit 7 is a conventional alumina-based two-stage reaction device, with a reaction temperature of 180-350℃; and the cooling unit 8 is a two-stage condenser / cooler unit.

[0098] Example 3:

[0099] This embodiment provides an SO2 reduction furnace and a sulfur recovery system including the SO2 reduction furnace. The difference from Embodiment 2 is that the reduction furnace body 1 corresponding to the high-temperature pyrolysis reduction zone 14 in this embodiment has a reflux gas inlet 17. The sulfur recovery system in this embodiment also includes a reflux fan 9. The gas inlet of the reflux fan 9 is connected to the dust removal and cooling unit 5, and the gas outlet of the reflux fan 9 is connected to the reduction furnace body 1, specifically, it can be connected to the reflux gas inlet 17 on the reduction furnace body 1. Figure 4 As shown, after the gas output from gas outlet 12 is cooled and dust removed, a portion of the gas can be returned to return gas inlet 17 via return fan 9.

[0100] Example 4:

[0101] This embodiment provides an SO2 reduction furnace, a sulfur recovery system, and a recovery method, mainly including the following:

[0102] ① The SO2 reduction reactor mainly includes the following units: a first feeding channel 2 and a first quantitative feeding bin 21 for auxiliary coke material at the top, and a corresponding gas isolation unit; a second feeding channel 3 and a second quantitative feeding bin 31 for high-volatile carbon-based material at the top, and a corresponding gas isolation unit; the upper middle part of the furnace is the auxiliary coke material decomposition and SO2 deep reduction zone, i.e., the storage zone 13; the lower middle part of the furnace is the high-temperature pyrolysis reduction zone 14 containing the auxiliary heating component 16, and the high-volatile carbon-based material pyrolysis reduction zone is located between the high-temperature pyrolysis reduction zone 14 and the storage zone 13; the auxiliary heating component 16 includes a heat storage shell 161, an electric heating element 162, and an online slag scraping and slag loosening element 163; the tail end of the furnace is the cooling recovery zone 15; and the bottom of the furnace is the slag discharge outlet 151, which is connected to the matching water-sealed slag pool 152.

[0103] ② The two carbon-based material feed inlets at the top of the reduction furnace adopt a concentric cylindrical design. The inner cylinder (i.e., the second feeding channel 3) transports high-volatile carbon-based materials, while the annular area (i.e., the first feeding channel 2) transports low-volatile coke materials. Both materials are metered into the upper part of the furnace from their respective top feed bins via a secondary rotary valve 4 through the annular feed inlet. The secondary rotary valve 4 ensures solid transport while preventing gas leakage, achieving gas isolation. The coke materials mainly accumulate at the top of the reactor (i.e., the storage area 13) and slowly move downwards during gasification and SO2 reduction. The high-volatile carbon-based materials directly enter the high-temperature pyrolysis reduction zone 14 in the middle of the furnace, mixing with the high-temperature coke and reacting with the SO2 and COS gas streams, undergoing thorough pyrolysis and gasification.

[0104] ③ When the mixed carbon-based material moves down to the middle and lower part of the reactor, the reactor temperature can be appropriately increased by the auxiliary heating component 16 to ensure that the remaining carbon-based material reacts fully with SO2 at a higher temperature; the high-temperature ash produced after the reaction is cooled down by contacting the low-temperature airflow in the cooling recovery zone 15, and is discharged from the reactor through the bottom slag outlet 151 and enters the water-sealed slag tank 152.

[0105] ④ The SO2 gas to be reduced enters from the bottom gas inlet 11 of the reactor. It is rapidly heated at the tail end of the furnace by direct contact with the high-temperature slag and rises to the high-temperature pyrolysis reduction zone 14. 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 materials in the middle and upper parts of the furnace, gradually transforming into COS.

[0106] ⑤ To promote the rapid reduction of SO2 and the gasification of carbon-based materials, the gas flow output from the gas outlet 12 at the top of the reactor is partially refluxed after passing through the dust removal and cooling unit 5. The refluxed gas enters from the reflux gas inlet 17 of the reactor through the reflux fan 9. COS is used to promote the low-temperature reduction of SO2 and the gasification of carbon materials, thereby significantly increasing the production load of the reactor.

[0107] ⑥ The gas output from the gas outlet 12 at the top of the reactor mainly consists of COS, CO and CO2. After dust removal and partial recirculation, the remaining gas flow passes through the catalytic hydrolysis unit 6 and reacts with an appropriate amount of SO2. After reacting through the Claus reaction unit 7, it is finally converted into high-purity sulfur gas. Then, the liquid or solid sulfur product is recovered through the cooling unit 8.

[0108] In this embodiment, the low-volatile carbon-based material is coke, activated carbon, and high-quality semi-coke with low volatile content, which are less likely to produce byproducts such as tar during high-temperature reaction. The carbon-based material is granular, with an equivalent particle diameter in the range of 5-50 mm, and its usage is 20%-50% of that of the high-volatile material.

[0109] In this embodiment, the high-volatile carbon-based material is coal, biomass, waste rubber, and low-quality semi-coke, which easily produce byproducts such as tar during low-temperature pyrolysis. The material is granular, with an equivalent particle diameter in the range of 5-50 mm.

[0110] In this embodiment, 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 SO2 / O2 concentration ratio greater than 5.

[0111] In this embodiment, the area between the high-temperature pyrolysis reduction zone 14 and the storage zone 13 is a pyrolysis reduction zone for high-volatile carbon-based materials and a mixing zone for low-volatile carbon-based materials and high-volatile carbon-based materials. Through the electric heating or heat storage effect of the auxiliary heating component 16, the temperature of this zone is maintained at 900-1100℃ to ensure sufficient reaction between SO2 and residual carbon in the slag.

[0112] In this embodiment, the high-volatile carbon-based material enters the high-temperature zone in the middle of the furnace directly through the central feed pipe. During its descent in the inner tube, it is gradually preheated and partially gasified. Then, it directly enters the high-temperature gasification zone and mixes with the high-temperature coke. Together, they react with the SO2 and COS gas flow and are fully pyrolyzed and gasified, thus avoiding the generation of tar.

[0113] In this embodiment, the reaction temperature in the storage zone 13 at the top of the reactor is 600–900°C. Its heat mainly comes from the exothermic reaction of 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 auxiliary heating component 16 is activated to supplement energy.

[0114] In this embodiment, the reactor diameter is 1000–4000 mm, and the height is 3–6 times its diameter. The reactor is lined with heat-insulating material and supplemented with external heat-insulating material. The apparent upward flow velocity of gases such as SO2 and reflux gas in the carbon layer is 0.05–0.25 m / s, and the total residence time of the carbon-based material in the reactor is 0.5–3.5 h.

[0115] In this embodiment, the output gas flow is partially recirculated, with the recirculation rate accounting for 10-30% of the gas outflow from the reactor. The COs and CO in the gas flow are used to promote the low-temperature reduction of SO2 and the gasification of carbon materials.

[0116] Example 5:

[0117] This embodiment provides an SO2 reduction furnace, a sulfur recovery system including the SO2 reduction furnace, and a sulfur recovery method for recovering sulfur and suppressing the generation of biomass tar by utilizing the reflux of coal coke and COS. The specific steps are as follows:

[0118] The SO2 reduction process is carried out using a fixed-bed reactor with a built-in tubular furnace (i.e., reduction furnace body 1). The reduction furnace body 1 has a diameter of 1m and a height of 3m, and is lined with glass wool for insulation to ensure efficient high-temperature reaction. An electric heating element (i.e., auxiliary heating component 16) is installed in the middle of the furnace to control the reaction temperature. A carbon-based material feeding unit is located at the top of the reduction furnace body 1, comprising an inner cylinder (second feeding channel 3) and an outer cylinder (first feeding channel 2). The inner cylinder is controlled by a two-stage rotary valve 4 to feed high-volatility carbon-based material, corn stalks, while the outer cylinder feeds low-volatility coal-based coke, ensuring that both carbon-based materials can fully contact the SO2 gas and react within the furnace.

[0119] The furnace temperature was heated to 1100℃. After the temperature stabilized, corn stalks and coke were added to the reactor through the inner and outer cylinders, respectively. The corn stalk addition rate was 2 kg / h, and the coke addition rate was 0.25 kg / h. The residence time of the carbon-based materials was approximately 1 minute. SO2 gas was added through a side inlet, with an SO2 content of 50% and the remainder being N2. The gas inlet flow rate for this inlet was 10 m³ / h. 3 / h.

[0120] Biomass (i.e., corn stalks) undergoes rapid pyrolysis upon entering the reactor, producing pyrolysis gas containing CO2, CH4, CO, H2, and some short-chain hydrocarbons. This pyrolysis gas first reacts with SO2 gas, reducing some of the SO2 to elemental sulfur. The biomass coke produced from pyrolysis, along with coal coke, reacts further with sulfur and the remaining SO2, converting SO2 and sulfur into COS. Through this process, SO2 is completely converted to COS, with a small amount of remaining coke discharged through the reactor's ash outlet at a rate of approximately 0.05 kg / h. The discharged remaining coke is mixed with the coal coke at the feed inlet and then reintroduced into the reactor to participate in the SO2 reduction reaction.

[0121] Due to the effects of COS and coal coke, the production of biomass tar is suppressed, decreasing from 0.1 g / g biomass without the addition of COS and coal coke to 0.03 g / g biomass. A very small amount of tar is intercepted by the filter components of the dust removal and cooling unit 5. A portion of the COS at the outlet is returned to the reactor inlet via the reflux system (i.e., reflux fan 9), where it pre-reduces SO2 to elemental sulfur, reducing the difficulty of SO2 reduction. At this point, the temperature inside the reactor is lowered to 1000℃ within 30 minutes, and SO2 is still completely converted. Furthermore, COS promotes the gasification process of CO2 in the pyrolysis gas with carbon-based materials, converting organic gases into H2 and CO, further reducing the tar content to 0.01 g / g biomass. COS is ultimately converted to H2S in the catalytic hydrolysis unit 6, and subsequently recovered as elemental sulfur with a purity >99% after passing through the Claus reaction unit 7 and the cooling unit 8.

[0122] Example 6:

[0123] This embodiment is basically the same as Embodiment 1, except that a water vapor inlet is provided in the air intake pipe. This inlet contains 25% water vapor, and the air intake flow rate is 2m³ / h. 3 / h. In this embodiment, H2 is generated by the steam reforming reaction between water vapor and organic pyrolysis gas to reduce the temperature of SO2 reduction reaction. At the same time, COS hydrolysis occurs to generate H2S, which shares part of the load of the subsequent catalytic hydrolysis unit.

[0124] The device parameters used in this embodiment are the same as in Embodiment 1, except for the steam inlet. The furnace temperature is heated to 1100℃. After the temperature stabilizes, corn stalks and coke are added to the reactor through the inner and outer cylinders, respectively. The corn stalk addition rate is 2 kg / h, and the coke addition rate is 0.25 kg / h. The residence time of the carbon-based materials is approximately 1 minute. SO2 gas is added through a side inlet, with an SO2 content of 50% and the remainder being N2. The gas inlet flow rate for this inlet is 10 m³ / h. 3 A single steam inlet is provided, containing 25% water vapor, with an inlet flow rate of 2 m³ / h. 3 / h. Water vapor and SO2 gas are mixed and then enter the reactor.

[0125] After entering the reactor, biomass undergoes rapid pyrolysis and steam reforming, producing product gases mainly composed of H2 and CO2. H2 first reacts with SO2 gas, reducing some of the SO2 gas to elemental sulfur. The biomass coke produced by pyrolysis, along with coal coke, reacts further with sulfur and the remaining SO2 and H2 to generate H2S. A small amount of residual coke is discharged through the reactor's ash outlet, at a rate of approximately 0.025 kg / h. The discharged residual coke is mixed with the coal coke at the feed inlet and then re-enters the reactor to participate in the SO2 reduction reaction.

[0126] Due to the action of H2O and H2, tar production is further reduced to 0.01 g / g biomass, with a very small amount of tar being intercepted by the filter components during the dust removal and cooling unit. A portion of the H2S at the outlet is returned to the reactor inlet via a reflux system, where it is pre-reduced with SO2 to convert SO2 into elemental sulfur, reducing the difficulty of SO2 reduction. At this point, the temperature inside the reactor is reduced to 900℃ within 30 minutes, and SO2 is still completely converted. Furthermore, H2S promotes the gasification process of CO2 in the pyrolysis gas with carbon-based materials, converting organic gases into CO, and the tar content decreases to 0.002 g / g biomass. The H2S is subsequently recovered as elemental sulfur with a purity >99% through the Claus reaction unit.

[0127] Example 7:

[0128] This embodiment is basically the same as Embodiment 1, except that a CO2 inlet is provided in the intake pipe, the intake air containing 75% CO2, and the intake flow rate is 0.8 m³ / s. 3 / h. In this embodiment, H2 and CO are generated by the dry reforming reaction between CO2 and organic pyrolysis gas to reduce the temperature of SO2 reduction reaction. Furthermore, the COS generated by SO2 reduction further promotes the gasification process of CO2 and organic matter, thereby reducing the amount of tar produced.

[0129] The device parameters used in this embodiment are the same as in Embodiment 1, except for the CO2 inlet. The furnace temperature is heated to 1100℃. After the temperature stabilizes, corn stalks and coke are added to the reactor through the inner and outer cylinders, respectively. The corn stalk addition rate is 2 kg / h, and the coke addition rate is 0.25 kg / h. The residence time of the carbon-based materials is approximately 1 minute. SO2 gas is added through a side inlet, with an SO2 content of 50% and the remainder being N2. The gas inlet flow rate for this inlet is 10 m³ / h. 3 CO2 and SO2 gases are mixed and then enter the reactor.

[0130] After entering the reactor, biomass undergoes rapid pyrolysis and CO2 reforming, producing a product gas primarily composed of CO. CO first reacts with SO2 gas, reducing some of the SO2 to elemental sulfur. The biomass coke produced from pyrolysis, along with coal coke, reacts further with sulfur, residual SO2, and CO to form COS. A small amount of residual coke is discharged through a slag outlet on the side of the reactor, at a rate of approximately 0.03 kg / h. The discharged residual coke is mixed with coal coke at the feed inlet and then re-enters the reactor to participate in the SO2 reduction reaction.

[0131] Due to the reforming effect of CO2, tar production is further reduced to 0.015 g / g biomass, with a very small amount of tar being intercepted by the filter components during the dust removal and cooling unit. A portion of the CO2 at the outlet is returned to the reactor inlet via a reflux system, where it is pre-reduced with SO2 to elemental sulfur, reducing the difficulty of SO2 reduction. At this point, the temperature inside the reactor is reduced to 950℃ within 30 minutes, and SO2 is still completely converted. Furthermore, CO2 promotes the gasification process of CO2 in the pyrolysis gas with carbon-based materials, converting organic gases into CO, and reducing the tar content to 0.005 g / g biomass. COS is ultimately converted to H2S in the catalytic hydrolysis unit, and subsequently recovered as elemental sulfur with a purity >99% via the Claus reaction unit.

[0132] Example 8:

[0133] This embodiment is basically the same as Embodiment 1, except that a steam inlet and a CO2 inlet are newly installed in the intake pipe. The CO2 intake contains 75% CO2, and the intake flow rate is 0.8 m³ / s. 3 / h; The steam intake contains 25% water vapor, and the intake flow rate is 2m³ / h. 3 / h. This implementation case utilizes the combined reforming reaction between CO2, water vapor, and organic pyrolysis gas to generate H2 and CO, thereby lowering the temperature of the SO2 reduction reaction. Furthermore, the H2S and a small amount of COS generated from SO2 reduction further promote the gasification process of CO2 and organic matter, reducing the amount of tar produced.

[0134] The apparatus parameters used in this embodiment are the same as in Embodiment 1, except for the steam and CO2 inlet parameters. The furnace temperature is heated to 1100℃, and after stabilization, corn stalks and coke are added to the reactor through the inner and outer cylinders, respectively. The corn stalk addition rate is 2 kg / h, and the coke addition rate is 0.25 kg / h. The residence time of the carbon-based materials is approximately 1 minute. SO2 gas is added through a side inlet, with an SO2 content of 50% and the remainder being N2. The gas inlet flow rate for this inlet is 10 m³ / h. 3 / h. Water vapor, CO2, and SO2 gases are mixed and then enter the reactor.

[0135] After entering the reactor, biomass undergoes rapid pyrolysis, accompanied by a reforming process involving steam and CO2, producing syngas primarily composed of CO and H2. The syngas first reacts with SO2 gas, reducing some of the SO2 to elemental sulfur. The biomass coke produced from pyrolysis, along with coal coke, further reacts with sulfur, residual SO2, and syngas to generate H2S. Due to the intense reforming reaction, almost no residual coke is discharged from the outlet.

[0136] Due to the reforming effect of steam CO2, almost no tar components are produced, with tar yield below 0.001 g / g biomass. Even when the temperature inside the reactor is lowered to 950℃ within 30 minutes, SO2 is still completely converted, and no tar is produced. The sulfur-containing components contain over 90% H2S, with the remainder being COS. COS is ultimately converted to H2S in the catalytic hydrolysis unit, and subsequently recovered as elemental sulfur with a purity >99% in the Claus reaction unit.

[0137] 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. An SO2 reduction furnace, comprising a furnace body (1), characterized in that, The reduction furnace body (1) has a gas inlet (11) at the bottom for introducing SO2 mixed gas, and a gas outlet (12) at the top. The reduction furnace body (1) includes a storage area (13), a high-temperature pyrolysis reduction area (14) and a cooling recovery area (15) from top to bottom. An auxiliary heating component (16) is provided in the high-temperature pyrolysis reduction area (14). The top of the reduction furnace body (1) is provided with a first feeding channel (2) and a second feeding channel (3) concentrically arranged within the first feeding channel (2); wherein, the first feeding channel (2) extends into the storage area (13) and communicates with the high-temperature pyrolysis reduction area (14), and the second feeding channel (3) passes through the first feeding channel (2) and communicates with the high-temperature pyrolysis reduction area (14); The top of the first feeding channel (2) is connected to a first quantitative feeding bin (21) for quantitatively conveying low-volatility auxiliary reducing materials; the top of the second feeding channel (3) is connected to a second quantitative feeding bin (31) for quantitatively conveying high-volatility carbon-based materials.

2. The SO2 reduction furnace according to claim 1, characterized in that, The diameter of the reduction furnace body (1) is 1000-4000mm, and the height of the reduction furnace body (1) is 3-6 times its diameter; The reduction furnace body (1) is lined with heat insulation material and externally with heat insulation material.

3. The SO2 reduction furnace according to claim 1, characterized in that, The bottom of the cooling recovery zone (15) is a slag discharge outlet (151), which is connected to the water-sealed sedimentation tank (152).

4. The SO2 reduction furnace according to claim 1, characterized in that, Both the first quantitative feed bin (21) and the second quantitative feed bin (31) are equipped with a two-stage rotary valve (4).

5. The SO2 reduction furnace according to claim 1, characterized in that, The auxiliary heating assembly (16) includes a heat storage shell (161), an electric heating element (162) disposed inside the heat storage shell (161), and an online slag scraping and slag loosening element (163) installed on the outer edge of the heat storage shell (161). The temperature of the storage zone (13) is 600-900℃, and the temperature of the high-temperature pyrolysis reduction zone (14) is 900-1100℃.

6. The SO2 reduction furnace according to claim 1, characterized in that, The high-temperature pyrolysis reduction zone (14) is provided with a reflux gas inlet (17) on the reduction furnace body (1); The gas output from the gas outlet (12) is returned to the return gas inlet (17) after being dedusted and cooled. The return flow rate of the return gas accounts for 10 to 30% of the gas outflow of the reduction furnace body (1).

7. The SO2 reduction furnace according to claim 1, characterized in that, The low-volatile auxiliary reducing materials include one or more of coke, activated carbon, and high-quality semi-coke, while the high-volatile carbon-based materials include one or more of biomass, coal, waste rubber, and low-quality semi-coke. Both the auxiliary reducing material and the carbon-based material are granular, and the equivalent diameter of the particles is 5-50 mm. The total residence time of the auxiliary reducing materials and carbon-based materials in the reduction furnace body (1) is 0.5 to 3.5 h.

8. The SO2 reduction furnace according to claim 1, characterized in that, The concentration of SO2 in the mixed gas introduced through the gas inlet (11) is not less than 15%, the content of O2 is not more than 10%, and the SO2 / O2 concentration ratio is greater than 5. The apparent upward flow velocity of the gas within the reduction furnace body (1) is 0.05–0.25 m / s.

9. A sulfur recovery system comprising the SO2 reduction furnace according to any one of claims 1-8, characterized in that, The sulfur recovery system also includes a dust removal and cooling unit (5), a catalytic hydrolysis unit (6), a Claus reaction unit (7), and a cooling unit (8) connected in sequence to the reduction furnace body (1).

10. A sulfur recovery method using the sulfur recovery system of claim 9, characterized in that, The sulfur recovery method includes the following steps: S1: Low-volatility auxiliary reducing material and high-volatility carbon-based material are added through the first feeding channel (2) and the second feeding channel (3) respectively, so that the two are mixed and gasified in the high-temperature pyrolysis reduction zone (14) to generate CO; S2: The gas to be reduced, containing SO2, is introduced into the gas inlet (11). The gas undergoes a reduction reaction with CO in the high-temperature pyrolysis reduction zone (14). S3: The gas after the reaction is output from the gas outlet (12), and after passing through the dust removal and cooling unit (5) and the catalytic hydrolysis unit (6), it reacts with SO2 and is converted into high-purity sulfur gas after passing through the Claus reaction unit (7). Finally, it is recovered by the cooling unit (8) to obtain sulfur products.

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