SO2 reduction furnace and sulfur recovery system

Abstract

The utility model relates to an SO2 reduction furnace and a sulfur recovery system. The SO2 reduction furnace comprises a reduction furnace body, and a gas inlet and a gas outlet are formed in the reduction furnace body; the reduction furnace body sequentially comprises a storage area, a high-temperature pyrolysis reduction area and a cooling recovery area from top to bottom, and an auxiliary heating assembly is arranged in the high-temperature pyrolysis reduction area; the top of the reduction furnace body is provided with a first feeding channel and a second feeding channel concentrically arranged in the first feeding channel. Wherein the first feeding channel extends into the storage area and is communicated with the high-temperature pyrolysis reduction area, and the second feeding channel penetrates through the first feeding channel and is communicated with the high-temperature pyrolysis reduction area. The first feeding channel is used for quantitatively conveying low-volatility auxiliary reducing materials, and the second feeding channel is used for quantitatively conveying high-volatility carbon-based materials. Compared with the prior art, the device disclosed by the utility model can effectively reduce the generation of tar in the SO2 reduction process and improve the yield and quality of sulfur.

Description

TECHNICAL FIELD

[0001] The utility model relates to SO2 reduction technical field especially is related to a SO2 reduction furnace and sulphur recovery system. BACKGROUND

[0002] SO2 is one of the most widely existing and highest content gaseous pollutants in coal-fired, non-ferrous and other industrial fields, and improper treatment will cause serious environmental pollution. The traditional treatment scheme is to convert it into gypsum by using lime dry method or wet method, but the desulfurization gypsum is poor in quality and low in value, and the accumulation of a large amount of desulfurization gypsum will also cause secondary pollution, so it is necessary to develop new SO2 treatment technology.

[0003] SO2 reduction conversion is a promising resource utilization method, which converts SO2 into elemental sulfur through the action of SO2 and reducing agent, which is not only convenient for storage and transportation, but also has high application value. Biomass reduction of SO2 is a new type of SO2 reduction technology, which has the advantages of wide source and low cost compared with traditional reducing agents such as CH4, H2 and CO, and the volatile content of biomass is high, which will pyrolyze at high temperature to produce reducing gas. These reducing gases contain H2, alkanes and olefins, which can reduce SO2 at a lower temperature, which also improves the ability of biomass to reduce SO2. However, the unreacted reducing organic gas is easy to condense when entering the downstream, causing pipeline blockage and equipment corrosion, and the accumulation of tar is the biggest defect and limiting factor of biomass utilization.

[0004] Patent CN119220276A discloses a low-tar biomass gasification furnace and its use method, which specifically adds filter medium through the movable plate, spray pipe head and valve flap on the side of the gasification furnace to adsorb and discharge tar. This method provides a method to reduce the damage of tar, but the generation of tar cannot be effectively inhibited, and long-term use will still cause corrosion to the filter part. Patent CN119240611A discloses a method for co-production and separate utilization of tar and hydrocarbon, which aims to separate the tar produced in the process of organic solid waste pyrolysis and gasification into light, medium and heavy tar according to the boiling range difference through in-situ hot separation, so as to facilitate utilization. However, the damage of tar in the pipeline has not been solved.

[0005] Therefore, in the process of biomass thermal conversion for reducing SO2, how to inhibit the generation and accumulation of tar is still a technical problem to be solved. UTILITY MODEL CONTENT

[0006] The utility model aims at inhibiting the generation and accumulation of tar in the process of biomass thermal conversion and provides a SO2 reduction furnace and sulphur recovery system.

[0007] The utility model discloses a purpose can be realized through the following technical scheme:

[0008] The utility model discloses a SO2 reduction furnace first provides, including reduction furnace body, the bottom of reduction furnace body is equipped with the gas import for containing SO2 mixed gas, and the top of reduction furnace body is equipped with gas export, the reduction furnace body is from top to bottom including the storage area, high temperature pyrolysis reduction area and cooling recovery area in proper order, be equipped with auxiliary heating assembly in high temperature pyrolysis reduction area,

[0009] The top of reduction furnace body is equipped with first feeding channel and the second feeding channel concentrically arranged in first feeding channel, wherein the first feeding channel extends into the storage area and is communicated with the high temperature pyrolysis reduction area, and the second feeding channel penetrates the first feeding channel and is communicated with the high temperature pyrolysis reduction area.

[0010] The top of first feeding channel is connected with first quantitative feeding bin for quantitatively conveying low-volatility auxiliary reduction material, and the top of second feeding channel is connected with second quantitative feeding bin for quantitatively conveying high-volatility carbon-based material.

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

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

[0013] Further, the reduction furnace body is lined with heat insulation material, and an external heat preservation material is additionally provided.

[0014] Further, the bottom of the cooling recovery area is a slag discharge outlet.

[0015] Further, the slag discharge outlet is connected with a water-sealed slag pool.

[0016] Further, both the first quantitative feeding bin and the second quantitative feeding bin are provided with a secondary rotary valve.

[0017] Further, the auxiliary heating assembly comprises a heat storage shell, an electric heating element arranged in the heat storage shell, and an online slag scraping and slag layer loosening element mounted on the outer edge of the heat storage shell.

[0018] Further, the high temperature pyrolysis reduction area is provided with a return gas inlet on the corresponding reduction furnace body.

[0019] Further, the gas output from the gas outlet is returned to the return gas inlet after dust removal and cooling.

[0020] The utility model also provides a kind of sulphur recovery system comprising the SO2 reduction furnace, and the sulphur recovery system further comprises dust removal cooling unit, catalytic hydrolysis unit, Claus reaction unit and cooling unit connected with the reduction furnace body in sequence.

[0021] Further, the sulphur recovery system further comprises a reflux fan.

[0022] Further, the gas inlet of the reflux fan is connected with the dust removal cooling unit, and the gas outlet is connected with the reduction furnace body.

[0023] Compared with the prior art, the utility model has the following beneficial effects:

[0024] (1) The SO2 reduction furnace of the utility model adopts concentrically arranged first feeding channel and second feeding channel, and the auxiliary reduction material and the main reduction material are partitioned and fed, so that the carbon-based material prone to produce tar by-products is directly fed into the high-temperature pyrolysis reduction zone of the SO2 reduction furnace to effectively prevent the production of tar.

[0025] (2) The utility model fully considers the performance difference between the low-volatility auxiliary reduction material and the high-volatility carbon-based material, and the two kinds of carbon-based materials are partitioned and fed, so that the high-volatility carbon-based material is directly input into the high-temperature pyrolysis reduction zone through the second feeding channel and is fully pyrolyzed and gasified in the high-temperature pyrolysis reduction zone, thereby effectively avoiding the production of tar by-products. The low-volatility auxiliary reduction material is input into the storage area through the first feeding channel, and then slowly moves downward to the high-temperature pyrolysis reduction zone during the gasification and SO2 reduction process, until it is mixed with the high-volatility carbon-based material in the high-temperature pyrolysis reduction zone and is fully pyrolyzed and gasified together.

[0026] (3) The SO2 reduction furnace of the utility model is specifically partitioned and set, and an auxiliary heating component is arranged in the high-temperature pyrolysis reduction zone, so as to adjust the gasification temperature of the high-temperature section.

[0027] (4) The SO2 reduction furnace of the utility model can also utilize part of the reflux of the intermediate product COS produced by SO2 reduction to further promote the low-temperature reduction of SO2 and avoid the production of tar, thereby improving the yield and quality of sulphur.

[0028] (5) The sulphur recovery system of the utility model adopts the SO2 reduction furnace, and in combination with the reflux, Claus reaction unit and the like, can significantly improve the yield and quality of sulphur, reduce the energy consumption and cost of sulphur production, and has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a structural schematic view of the SO2 reduction furnace of the utility model.

[0030] Figure 2The utility model discloses a structure diagram of the auxiliary heating assembly of SO2 reduction furnace.

[0031] Figure 3 The utility model discloses a structure diagram of the sulfur recovery system of embodiment 3.

[0032] Figure 4 The utility model discloses a structure diagram of the sulfur recovery system of embodiment 4.

[0033] Marking explanation in the drawing:

[0034] 1-reduction furnace body, 11-gas import, 12-gas export, 13-accumulation area, 14-high temperature pyrolysis reduction area, 15-cooling recovery area, 151-discharge outlet, 152-water seal sediment pool, 16-auxiliary heating assembly, 161-heat storage shell, 162-electric heating element, 163-online slag scraping and slag layer loosening element, 17-backflow gas import;

[0035] 2-first feeding channel, 21-first ration feeding bin;

[0036] 3-second feeding channel, 31-second ration feeding bin;

[0037] 4-second rotary valve;

[0038] 5-dust removal cooling unit;

[0039] 6-catalytic hydrolysis unit;

[0040] 7-Claus reaction unit;

[0041] 8-cooling unit;

[0042] 9-backflow fan. Specific embodiments

[0043] The utility model will be explained in detail below in combination with the drawings and specific embodiments. The embodiment is implemented on the premise of the technical scheme of the utility model, and detailed implementation mode and specific operation process are given, but the protection scope of the utility model is not limited to the following examples.

[0044] In the utility model, it needs to be explained that, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and thus cannot be understood as limiting the utility model; the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance; in addition, unless explicitly specified and limited, the terms "mounting", "connection" and "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium, or the communication between two elements. For ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0045] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0046] In view of the technical problem that the conventional carbon-based material containing high volatile matter is prone to produce tar in the reduction process of SO2, the utility model provides an SO2 reduction furnace which can greatly reduce the production of tar in the reduction process of SO2.

[0047] The SO2 reduction furnace of the utility model comprises a reduction furnace body 1, a gas inlet 11 for introducing SO2-containing mixed gas is arranged at the bottom of the reduction furnace body 1, and a gas outlet 12 is arranged at the top of the reduction furnace body 1. The reduction furnace body 1 comprises a storage area 13, a high-temperature pyrolysis reduction area 14 and a cooling recovery area 15 from top to bottom in sequence, and an auxiliary heating assembly 16 is arranged in the high-temperature pyrolysis reduction area 14. A first feeding channel 2 is arranged at the top of the reduction furnace body 1, and a second feeding channel 3 is concentrically arranged in 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, and the second feeding channel 3 penetrates 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 with a first quantitative feeding bin 21 for quantitatively conveying low-volatility auxiliary reduction materials, and the top of the second feeding channel 3 is connected with a second quantitative feeding bin 31 for quantitatively conveying high-volatility carbon-based materials.

[0048] In some specific embodiments, the diameter of the reduction furnace body 1 is 1000-4000mm.

[0049] In some specific embodiments, the height of the reduction furnace body 1 is 3-6 times its diameter.

[0050] In some specific embodiments, the reduction furnace body 1 is lined with heat-insulating material and externally insulated.

[0051] In some specific embodiments, the bottom of the cooling recovery zone 15 is a slag discharge outlet 151.

[0052] In some specific embodiments, the slag discharge outlet 151 is connected to the water-sealed sedimentation tank 152.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] In some specific embodiments, the gas output from the gas outlet 12 is cooled and removed by the dust removal and cooling unit 5, and then returned to the return gas inlet 17 by the return fan 9.

[0058] To recover sulfur using the aforementioned SO2 reduction furnace device, this invention also provides a 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, all connected in sequence to the reduction furnace body 1.

[0059] 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.

[0060] 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.

[0061] Example 1:

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] Example 2:

[0067] This embodiment provides an SO2 reduction furnace.

[0068] The SO2 reduction furnace in 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] Example 3:

[0074] This embodiment provides a sulfur recovery system. For example... Figure 3 As shown, the sulfur recovery system of this embodiment includes the reduction furnace body 1 in embodiment 1, and 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.

[0075] Among them, the dust removal and cooling unit 5 can use conventional cyclone dust collectors, high-temperature ceramic filters and other devices; the catalytic hydrolysis unit 6 is a catalytic hydrolysis reaction unit filled with an alumina-based catalytic filling 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.

[0076] Example 4:

[0077] This embodiment provides a sulfur recovery system. The difference from Embodiment 3 is that the high-temperature pyrolysis reduction zone 14 in this embodiment has a reflux gas inlet 17 on the reduction furnace body 1. 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, to the reflux gas inlet 17 on the reduction furnace body 1. Figure 4 As shown, the gas output from gas outlet 12, after passing through dust removal and cooling unit 5, can have part of the gas returned to return gas inlet 17 by return fan 9.

[0078] Example 5:

[0079] This embodiment provides an SO2 reduction furnace and a sulfur recovery system, which mainly includes the following:

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] Application example:

[0095] This embodiment provides an SO2 reduction furnace and a sulfur recovery system including the SO2 reduction furnace, used to recover sulfur and suppress the generation of biomass tar by utilizing the reflux of coal coke and COS. The specific steps are as follows:

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] The above description of the embodiments is provided to enable those skilled in the art to understand and use the utility model. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present utility model 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 utility model without departing from its scope should be within the protection scope of the present utility model.

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.

3. The SO2 reduction furnace according to claim 1, characterized in that, The reduction furnace body (1) is lined with heat insulation material and externally with heat insulation material.

4. The SO2 reduction furnace according to claim 1, characterized in that, The bottom of the cooling recovery zone (15) is the slag outlet (151).

5. The SO2 reduction furnace according to claim 4, characterized in that, The slag discharge outlet (151) is connected to the water-sealed sedimentation tank (152).

6. 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).

7. 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 in 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).

8. 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).

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 system according to claim 9, characterized in that, The sulfur recovery system 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 is connected to the reduction furnace body (1).

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