Calcium-based dry desulfurization system

Abstract

The utility model discloses a calcium-based dry desulfurization system and belongs to a flue gas desulfurization technology. The calcium-based dry desulfurization system comprises a desulfurizing agent conveying device, a desulfurizing tower, a gas-solid separation device and a byproduct reuse device, the desulfurizing agent conveying device is used for spraying a desulfurizing agent into the desulfurizing tower, and the desulfurizing tower is connected with the gas-solid separation device; the gas-solid separation device comprises a first discharge port for outputting gas and a second discharge port for outputting byproducts; the byproduct reuse device comprises a conveying module, the conveying module comprises a powder bin, feeding equipment, a fan and spraying equipment, the powder bin is connected with the second discharge outlet and the feeding equipment, the feeding equipment is connected with the spraying equipment, and the spraying equipment is connected with the fan. The fan is used for enabling by-products in the powder bin to flow to the spraying equipment through the feeding equipment, and the spraying equipment is arranged in the desulfurization tower. According to the utility model, the utilization rate of the desulfurizer is effectively improved by reusing byproducts.

Description

Technical Field

[0001] The utility model relates to a flue gas desulfurization technology, in particular to a calcium-based dry desulfurization system. Background Art

[0002] Calcium-based dry desulfurization is a flue gas desulfurization technology that absorbs and converts sulfur dioxide in the flue gas by spraying calcium-based dry desulfurizer into the flue gas, so that the sulfide in the flue gas meets the emission standards. The process flow of calcium-based dry desulfurization technology generally includes injection, contact reaction between flue gas and desulfurizer, and transportation of waste slag. During the injection process, the calcium-based dry desulfurizer (such as calcium-based ultrafine powder) is sent into the flue through the powder conveying control equipment. During the contact reaction between the flue gas and the desulfurizer, the sulfur dioxide in the flue gas and the active calcium in the calcium-based dry desulfurizer undergo a chemical reaction. In the waste slag transportation link, the reacted substances are dusted and the obtained by-products are stored in the powder bin. The transport vehicle transports the by-products from the powder bin as required. The calcium-based dry desulfurization system is particularly suitable for the treatment of flue gas sulfides in furnaces such as heating furnaces, hot blast furnaces, and power plant boilers because of its low investment, low operating cost, simple operation, and convenient maintenance.

[0003] However, calcium-based dry desulfurization is a pure dry desulfurization technology. Compared with semi-dry desulfurization, rotary spray desulfurization and wet desulfurization, its utilization rate has always been low because it does not involve water. Especially when the desulfurizer used has poor activity or the system design is not perfect, it will lead to a large amount of desulfurizer used, high operating costs, and waste of energy resources. Utility Model Content

[0004] The purpose of the present application is to solve the problems of large amount of desulfurizer, high operating cost and waste of resources in calcium-based dry desulfurization technology, and a calcium-based dry desulfurization system is proposed for this purpose.

[0005] In order to achieve the above-mentioned purpose, the utility model provides the following technical solution.

[0006] A calcium-based dry desulfurization system, comprising a desulfurizer conveying device, a desulfurization tower, a gas-solid separation device and a by-product reuse device, wherein the desulfurizer conveying device is used to spray the desulfurizer into the desulfurization tower, the desulfurization tower is connected to the gas-solid separation device, and the gas-solid separation device comprises a first discharge port for outputting gas and a second discharge port for outputting by-products;

[0007] The by-product reuse device includes a conveying module, which includes a powder bin, a feeding device, a fan and an injection device. The powder bin is respectively connected to the second discharge port and the feeding device, and the feeding device is connected to the injection device. The fan is used to make the by-products in the powder bin flow to the injection device via the feeding device, and the injection device is built in the desulfurization tower.

[0008] As an optional solution, the feeding equipment includes a feeding shell, a screw rod and a driving component, the feeding shell includes an extrusion part, the screw rod is rotatably connected between the upper opening and the lower opening of the extrusion part, and the driving component is used to drive the screw rod to rotate so that the powder is squeezed out from the discharge port of the extrusion part and flows to the lower opening.

[0009] As an optional scheme, the extrusion part includes an inner shell and an outer shell, the upper opening is formed on the inner shell, the lower opening is formed on the outer shell, an interlayer space is formed between the inner shell and the outer shell, the spiral rod is arranged on the inner shell, and a plurality of discharge ports are arranged in the circumferential direction of the inner shell so that the powder can flow from the interlayer space to the lower opening.

[0010] As an optional solution, the extrusion part includes an extrusion shell and a discharge plate, the two ends of the extrusion shell respectively form the upper opening and the lower opening, the discharge plate is arranged on the extrusion shell and arranged close to the lower opening, and a plurality of discharge ports are provided on the discharge plate.

[0011] As an optional solution, the feeding shell further includes a funnel portion and a buffer portion, the upper end of the funnel portion is connected to the powder bin, and the lower end is connected to the buffer portion, and the buffer portion is narrow at both ends and wide in the middle.

[0012] As an optional solution, the feeding shell also includes a first guide part and a second guide part, the two ends of the first guide part are respectively connected to the extrusion part and the second guide part, the first guide part is in a trumpet shape that is narrow at the top and wide at the bottom, and the second guide part is inclined relative to the vertical direction.

[0013] As an optional solution, the feeding device further includes an air sealing structure, which is arranged at the discharge port, on the first guide part or the second guide part, and the air sealing structure is used to prevent the air flow from backflowing into the powder bin.

[0014] As an optional solution, the powder silo includes a closed silo body, and the conveying module also includes a dust removal device, an air cannon and a vibrator. The lower end of the closed silo body is connected to the upper end of the feeding device, the dust removal device is arranged on the top plate of the closed silo body, and the air cannon and the vibrator are respectively arranged at the lower part of the closed silo body.

[0015] As an optional solution, the conveying module also includes a mixing device, which has a powder inlet, an air inlet and an outlet, the powder inlet is connected to the feeding device, the air inlet is connected to the fan, and the outlet is connected to the injection device.

[0016] As an optional solution, a dehumidification device or a heating device is arranged between the fan and the mixing device, and the dehumidification device and the heating device are used to remove moisture from the air.

[0017] As an optional solution, the mixing device includes a first mixing section and a second mixing section that are connected to each other, the first mixing section having a mixing chamber, the first mixing section being provided with an air inlet and a powder inlet that are connected to the mixing chamber, the second tubular mixing section being provided with the outlet, and the middle area of ​​the second mixing section being narrower than the two ends.

[0018] As an optional solution, the by-product reuse device includes a switching device and two conveying modules, the switching device is respectively connected to the two conveying modules, and the switching device is connected to the pipeline between the fan and the mixing device. The fan of any conveying module can provide power to the mixing device, the feeding device, the powder bin and the injection device of the other conveying module through the switching device.

[0019] As an optional scheme, the switching device includes a first control valve, a second control valve and a third control valve, the first control valve is connected to one of the delivery modules and the second control valve, the second control valve is connected to another of the delivery modules, the third control valve is connected between the first control valve and the second control valve, and the third control valve is also connected to the purge gas source of the by-product reuse device.

[0020] As an optional solution, the blower adopts a Roots blower.

[0021] As an optional solution, an observation device and / or a pressure difference detection device and / or a blowing interface is provided on the pipeline between the mixing device and the injection device.

[0022] As an optional solution, the injection device includes a plurality of injection points evenly distributed on a cross section in the direction of smoke flow.

[0023] As an optional solution, the desulfurizing agent conveying device and the by-product reuse device have the same structure, wherein the desulfurizing agent conveying device conveys calcium-based ultrafine powder, and the by-product reuse device conveys by-products.

[0024] The utility model has at least the following beneficial effects:

[0025] By setting up a by-product reuse device and utilizing the conveying module of the by-product reuse device to convey the by-products back to the desulfurization tower, the desulfurization components in the by-products further react with the flue gas, thereby improving the utilization rate of the desulfurizer. The desulfurization components contained in the powder bin of the by-product reuse device are reduced from 50% to below 30%.

[0026] Whether it is the by-product reuse device or the desulfurizer conveying device, the layout of the switching equipment, fans, powder bins, feeding equipment, mixing equipment and injection equipment realizes the backup of the two fans and the backup of the two sets of powder bins, feeding equipment, mixing equipment and injection equipment. When any equipment in the device fails or the local pipeline is blocked, there is a backup plan to ensure normal operation. The whole system has a backup plan, which ensures the safety and high efficiency of the system and improves reliability and stability.

[0027] Whether it is a by-product reuse device or a desulfurizer conveying device, the fan is installed at the front end of the powder bin, feeding equipment and mixing equipment to convey the powder to the desulfurization tower in a positive pressure manner. At this time, the fan is located at the front end of the conveying module, which can make the pressure distribution in various pipelines more uniform, avoiding the deviation caused by negative pressure and local accumulation and blockage caused by deviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The technical features and advantages of the present invention may be more fully understood by referring to the following detailed description in conjunction with the accompanying drawings.

[0029] Figure 1 This is a schematic diagram of a calcium-based dry desulfurization system according to an embodiment of the present utility model.

[0030] Figure 2 This is a schematic diagram of a by-product reuse device according to an embodiment of the utility model.

[0031] Figure 3 It is a partial cross-sectional view of a feeding device according to an embodiment of the utility model.

[0032] Figure 4 This is a partial cross-sectional view of a feeding device according to another embodiment of the present invention.

[0033] Reference numerals:

[0034] 100, desulfurizing agent conveying device; 200, desulfurizing tower; 300, gas-solid separation device; 3001, dust collector; 3002, ash discharge silo pump; 400, chimney; 500, by-product reuse device;

[0035] 1. Fan; 2. Mixing equipment; 21. First mixing section; 211. Mixing chamber; 212. Air inlet; 213. Powder inlet; 22. Second mixing section; 221. Outlet; 3. Feeding equipment; 31. Feeding shell; 311. Extrusion section; 3111. Upper opening; 3112. Lower opening; 3113. Inner shell; 3114. Outer shell; 3115. Interlayer space; 3116. Extrusion shell; 3117. Discharging plate; 312. Funnel; 313. Buffer; 314. First Guide part; 315, second guide part; 32, screw rod; 33, driving component; 4, powder bin; 5, injection equipment; 51, injection point; 6, switching equipment; 61, first control valve; 62, second control valve; 63, third control valve; 7, dehumidification equipment; 8, heating equipment; 9, air path control valve; 10, dust removal equipment; 11, air cannon; 12, vibrator; 13, gate valve; 14, observation equipment; 15, pressure differential detection equipment; 16, spray interface; 161, spray control valve. DETAILED DESCRIPTION

[0036] Unless otherwise defined, the technical terms or scientific terms used in this specification and claims shall have the common meanings understood by persons having ordinary skills in the technical field to which the present invention belongs.

[0037] refer to Figures 1 to 4 Understand. The embodiment of the utility model provides a calcium-based dry desulfurization system, and the desulfurizer adopts calcium-based ultrafine powder. After the desulfurizer reacts with the flue gas, a powdery by-product is generated, and the by-product components are mainly calcium hydroxide, calcium sulfate and calcium carbonate. Since the utilization rate of the desulfurizer is not high, the by-product generally still contains about 50% of effective desulfurization components (i.e. calcium hydroxide). The utility model effectively improves the utilization rate of the desulfurizer by reusing the by-product.

[0038] The calcium-based dry desulfurization system includes a desulfurizing agent conveying device 100, a desulfurization tower 200, a gas-solid separation device 300, a chimney 400, and a by-product reuse device 500. The desulfurizing agent conveying device 100 is connected to the desulfurization tower 200, the desulfurization tower 200 is connected to the gas-solid separation device 300, the gas-solid separation device 300 includes a first discharge port for outputting gas and a second discharge port for outputting by-products, the first discharge port is connected to the chimney 400, the second discharge port is connected to the by-product reuse device 500, and the by-product reuse device 500 is connected to the desulfurization tower 200. The desulfurizer conveying device 100 is used to spray desulfurizer powder (calcium-based ultrafine powder used in this system) into the desulfurization tower 200. The calcium-based ultrafine powder reacts chemically with sulfur dioxide in the flue gas. The gas-solid mixed substance formed after the reaction flows from the upper end of the desulfurization tower 200 to the gas-solid separation device 300. The gas-solid separation device 300 performs gas-solid separation on it. The separated gas is discharged into the atmosphere from the chimney 400. The separated solid is in powder form and stored in the by-product reuse device 500. In addition to the function of storing by-products, the by-product reuse device 500 also has the function of sending the by-products into the desulfurization tower 200 for recycling. When the control part determines that the by-products cannot be recycled, the stored by-products are unloaded onto the loading truck by a suction and exhaust vehicle or other means.

[0039] The desulfurization tower 200 is understood in a broad sense as a device that provides space for the reaction of flue gas and powder, including a structure formed by flue modification. The flue gas to be treated from various furnaces (such as heating furnace / hot blast furnace / power plant boiler / lime kiln) enters the desulfurization tower 200 from the bottom and flows out from the top after the reaction.

[0040] The by-product reuse device 500 includes a switching device 6 and two conveying modules. The two conveying modules are used to convey powder to the desulfurization tower 200. The switching device 6 is used to realize the function of the two conveying modules serving as backup for each other.

[0041] The conveying module includes a fan 1, a mixing device 2, a feeding device 3, a powder bin 4 and an injection device 5. The fan 1 is connected to the air inlet 212 of the mixing device 2 and is used to blow air into the mixing device 2. The upper end of the powder bin 4 is connected to the second discharge port of the gas-solid separation device 300. The lower end of the powder bin 4 is connected to the powder inlet 213 of the mixing device 2 through the feeding device 3. The powder bin 4 is filled with by-products, which are in powder form. The feeding device 3 is used to control the feeding amount of the by-products. The calcium-based ultrafine powder enters the mixing device 2 from the powder inlet 213 and mixes with the gas. The outlet 221 of the mixing device 2 is connected to the injection device 5, which is built in the desulfurization tower 200. The mixed material is sprayed into the desulfurization tower 200 through the injection device 5. The switching device 6 is respectively connected to the two conveying modules, and the switching device 6 is connected to the pipeline between the fan 1 and the mixing device 2 so that the two fans 1 can be used as backup for each other.

[0042] In the embodiment of the utility model, a by-product reuse device is provided, and the by-product is transported back to the desulfurization tower 200 by using the conveying module of the by-product reuse device. The desulfurization components in the by-product further react with the flue gas, thereby improving the utilization rate of the desulfurizer. The fan 1 is arranged at the front end of the powder bin 4, the feeding device 3 and the mixing device 2, and the by-product is transported to the desulfurization tower 200 in a positive pressure manner. At this time, the fan 1 is located at the front end of the conveying module, which can make the pressure distribution in various pipelines more uniform, avoiding the deviation caused by negative pressure and the local accumulation and blockage caused by the deviation. The utility model is provided with a switching device 6, and the connection point between the switching device 6 and the conveying module is arranged between the fan 1 and the mixing device 2, so that the two fans 1 can be used as backup for each other, and the two groups of powder bins 4, feeding devices 3, mixing devices 2 and injection devices 5 can be used as backup for each other. For example, with Figure 2 The upper and lower directions shown are used as references. When the fan 1 of the upper conveying module in operation fails, the switching device 6 switches the lower fan 1 to provide power for the upper group of powder bins 4, feeding devices 3, mixing devices 2 and injection devices 5, or directly switches to the lower conveying module for operation. When the powder bin 4 of the upper conveying module in operation has a problem (such as insufficient by-products, blockage, etc.), the switching device 6 switches the upper fan 1 to provide power for the lower group of powder bins 4, feeding devices 3, mixing devices 2 and injection devices 5, or directly switches to the lower group of conveying modules for operation. When the upper fan 1 and the lower mixing device 2 fail, the lower fan 1 and the upper group of powder bins 4, feeding devices 3, mixing devices 2 and injection devices 5 are switched to work together. In other words, when any device of the by-product reuse device 500 fails or a local pipeline is blocked, there is a backup plan to ensure normal operation, that is, there is a full system backup plan, thereby ensuring the safety and high efficiency of the system and improving reliability and stability.

[0043] In the embodiment of the utility model, both fans 1 are Roots blowers. A dehumidification device 7 or a heating device 8 is arranged between the fan 1 and the mixing device 2, and the dehumidification device 7 and the heating device 8 are used to remove moisture from the air. Specifically, one side of the dehumidification device 7 (or the heating device 8) is connected to the fan 1 through a pipeline, and the other side is connected to the air inlet 212 of the mixing device 2 through a pipeline. An air path control valve 9 is arranged between the dehumidification device 7 (or the heating device 8) and the mixing device 2 to control the on-off of the pipeline; the dehumidification device 7 can adopt an adsorption dehumidification method, such as the dehumidification device 7 has a built-in hygroscopic material to absorb moisture in the air, and the heating device 8 uses heating to evaporate moisture to dry the air. By removing moisture from the air, the influence of air humidity on the desulfurization components in the by-products and the condensation water problem caused by temperature drop are reduced, the probability of by-product blockage is reduced, and the reliability of the system is improved.

[0044] In the embodiment of the utility model, the switching device 6 includes a first control valve 61, a second control valve 62 and a third control valve 63. The first control valve 61 is connected to a conveying module and the second control valve 62, and the connection position of the first control valve 61 and the conveying module is between the gas circuit control valve 9 and the mixing device 2. The second control valve 62 is connected between the gas circuit control valve 9 and the mixing device 2 of another conveying module. The third control valve 63 is connected between the first control valve 61 and the second control valve 62. The third control valve 63 is also connected to the purge gas source of the by-product reuse device 500. The first control valve 61, the second control valve 62 and the third control valve 63 can all adopt two-way solenoid valves. When the first control valve 61 and the third control valve 63 are connected and the second control valve 62 is disconnected, the purge gas source is connected. Figure 2 When the first control valve 61 is disconnected and the second control valve 62 and the third control valve 63 are connected, the purge gas source is connected. Figure 2 In the conveying module below, when the first control valve 61 and the second control valve 62 are both connected, the two fans 1 serve as backup for each other. In addition, the purge gas source uses nitrogen, which is transported through the factory pipe network.

[0045] In an embodiment of the utility model, the powder bin 4 includes a closed bin body, and the conveying module also includes a dust removal device 10, an air cannon 11 and a vibrator 12. The lower end of the closed bin body is connected to the upper end of the feeding device 3, and the top of the closed bin body is provided with a dust removal device 10. The lower part of the closed bin body includes a funnel-shaped structure, and the air cannon 11 and the vibrator 12 are arranged around the funnel-shaped structure to assist the by-products to flow to the feeding device 3 to prevent blockage.

[0046] In the embodiment of the utility model, the feeding device 3 includes a feeding shell 31, a screw rod 32 and a driving component 33. The upper end of the feeding shell 31 is connected to the lower end of the powder bin 4 through a pipeline, and the lower end of the feeding shell 31 is connected to the mixing device 2; the feeding shell 31 includes an extrusion part 311, and the extrusion part 311 has an upper opening 3111 and a lower opening 3112. The screw rod 32 is rotatably connected between the upper opening 3111 and the lower opening 3112 of the extrusion part 311. The driving component 33 is used to drive the screw rod 32 to rotate, so that the by-product is squeezed out from the discharge port of the extrusion part 311 and flows to the lower opening 3112. Such a setting can prevent the by-product from flowing back to a certain extent.

[0047] In some embodiments, Figure 3As shown, the extrusion part 311 includes an inner shell 3113 and an outer shell 3114, an upper opening 3111 is formed on the inner shell 3113, a lower opening 3112 is formed on the outer shell 3114, the upper end of the outer shell 3114 is fixed to the surface of the inner shell 3113, an interlayer space 3115 is formed between the inner shell 3113 and the outer shell 3114, the interlayer space 3115 is connected to the lower opening 3112, the screw rod 32 passes through the inner shell 3113, and a plurality of discharge ports are arranged in the circumferential direction of the inner shell 3113. By-products enter the inner shell 3113 from the upper opening 3111, and during the rotation of the screw rod 32, the by-products enter the interlayer space 3115 from the discharge port, and further flow to the mixing device 2 from the lower opening 3112.

[0048] As an alternative to the above embodiment, in some other embodiments, such as Figure 4 As shown, the extrusion part 311 includes an extrusion shell 3116 and a discharge plate 3117. The upper and lower ends of the extrusion shell 3116 form an upper opening 3111 and a lower opening 3112 respectively. The extrusion shell 3116 shrinks at the two openings to form a structure with a large inner diameter in the middle and a small inner diameter at both ends, such as a spherical structure. This structure is convenient for extruding by-products. The discharge plate 3117 is fixed on the extrusion shell 3116 and is arranged near the lower opening 3112. The discharge plate 3117 is provided with a plurality of discharge ports. During the rotation of the screw rod 32, the by-products fall from the discharge plate 3117.

[0049] Continue to refer Figures 1 to 4 Figure 2 Understand. In the embodiment of the utility model, the feeding shell 31 also includes a funnel part 312 and a buffer part 313. The upper end of the funnel part 312 is provided with a top plate structure that is narrow at the top and wide at the bottom. The center of the top plate structure is connected to the powder bin 4 through a pipeline, and a plug valve is provided on the pipeline to control the on-off. The lower end of the funnel part 312 is connected to the buffer part 313. The buffer part 313 is narrow at both ends and wide in the middle, which can reduce the impact of the falling by-products on the spiral rod 32.

[0050] The feeding shell 31 also includes a first flow guide portion 314 and a second flow guide portion 315. The two ends of the first flow guide portion 314 are respectively connected to the extrusion portion 311 and the second flow guide portion 315. The first flow guide portion 314 adopts a trumpet-shaped structure that is narrow at the top and wide at the bottom. The second flow guide portion 315 is inclined relative to the vertical direction. The first flow guide portion 314 and the second flow guide portion 315 can prevent the backflow of by-products to a certain extent.

[0051] The feeding device 3 also includes an air sealing structure, which is equivalent to a one-way valve and is used to prevent the airflow from flowing back into the powder bin 4. The air sealing structure can be set at the discharge port, one for each discharge port, or can be set on the first guide part 314 or the second guide part 315, in which case only one is required.

[0052] In some embodiments, Figure 1-4 As shown, the feeding device 3 adopts a single spiral structure, that is, a spiral rod 32 and a driving component 33 are provided. In some other embodiments, a double spiral structure may be adopted, and two spiral rods 32 each correspond to a driving component 33, and the two spiral rods 32 turn in opposite directions to increase the extrusion force on the by-products. The driving component 33 may include a motor, a reducer, and a pulley transmission mechanism. The motor is connected to the input end of the pulley transmission mechanism through the reducer, and the output end of the pulley transmission mechanism is fixedly connected to the spiral rod 32.

[0053] Since the concentration of sulfur dioxide in the flue gas generated in the kiln fluctuates frequently, in order to feed accurately, in some embodiments of the utility model, a spiral feeding method is adopted, and a control method is combined to reduce the influence of the frequent fluctuations in the concentration of sulfur dioxide. Specifically, a sulfide index is set. The sulfide index refers to a value that meets the standard set according to the requirements of sulfides in the gas discharged into the atmosphere specified in the national standard or other standards. For example, the standard requires that the sulfide content does not exceed 35 mg per cubic meter. The sulfide index can be a value equal to or less than 35 mg per cubic meter, and 30 mg per cubic meter can be selected; a control board, a first detector and a second detector are set. The first detector is set at the lower end of the desulfurization tower 200 to detect the concentration of sulfur dioxide in the flue gas. The control board pre-stores the sulfide index and the calculation program. The control board responds to the detection result of the first detector based on the sulfide index and the calculation program. The frequency of the desulfurizer conveying device 100 is calculated based on the detection results and the sulfide index, and corresponding instructions are sent to the desulfurizer conveying device 100 to perform frequency conversion control on it; the second detector detects the concentration of sulfides at the outlet of the desulfurization tower. The control board has a judgment program. The control board judges whether the detection data of the second detector is close to or reaches the sulfide index. If so, a warning signal is sent to the electronic display screen or alarm device of the system. The operator or the system itself cuts off the by-product reuse device from conveying by-products to the desulfurization tower according to the warning signal, and unloads the by-products in the powder bin onto a vehicle for transportation away. After transportation away, the next round of recycling can be entered.

[0054] Continue to refer Figure 1 and Figure 2Understand. In the embodiment of the utility model, the mixing device 2 includes a first mixing section 21 and a second mixing section 22 that are connected. The first mixing section 21 has a mixing chamber 211, which is square in shape as a whole. An air inlet 212 and a powder inlet 213 are arranged on the first mixing section 21, and the mixing chamber 211 is connected from two different directions. The gas and solid entering the mixing chamber 211 generate a number of small vortices due to different flow directions, which accelerate the mixing. A connecting port is formed at the position where the first mixing section 21 and the second mixing section 22 are connected. The apertures of the air inlet 212, the powder inlet 213 and the connecting port are all smaller than the area of ​​their respective surfaces, so that the speed of the by-products and gases entering the mixing chamber 211 is reduced, and the formed gas-solid mixture is accelerated when it enters the second mixing section 22 from the mixing chamber 211. The second mixing section 22 has an outlet 221, and the middle area of ​​the second mixing section 22 is narrower than the two ends. The speed of the gas is rapidly increased in the middle area of ​​the second mixing section 22, so that a vacuum is formed around it, and the by-products are attached. The speed of the gas-solid mixture is slowed down near the outlet 221, and the by-products and the gas are further fully mixed. Affected by the shapes of the first mixing section 21 and the second mixing section 22, the gas and the by-products continuously collide with the irregular inner wall of the mixing device 2 during the flow process, forming small vortices, accelerating turbulence, accelerating mixing, and improving the uniformity of the mixture. The by-products react more fully with the sulfide, thereby improving the utilization rate of the by-products, reducing the operating cost, and also reducing the blockage.

[0055] Continue to refer Figure 1 and Figure 2 Understand. An observation device 14, a pressure differential detection device 15 and a blowing interface 16 are arranged on the pipeline between the mixing device 2 and the injection device 5. Multiple observation devices 14 can be arranged, using a sight glass or a peephole, etc., to observe the transportation situation in the pipeline. Multiple pressure differential detection devices 15 are arranged, distributed at multiple detection points of the pipeline, and are used to detect the pressure and pressure difference of the pipeline at each detection point. The blowing interface 16 is connected to the nitrogen gas source through a pipeline so as to purge nitrogen into the pipeline according to the detection result of the pressure differential detection device 15 to avoid blockage; the pipeline is provided with a blowing control valve 161 at a position close to the blowing interface 16 to control the on and off of the gas source; multiple blowing interfaces 16 can be arranged on the pipeline, and one is arranged at each end of the elbow in the area with the elbow.

[0056] Continue to refer Figure 1 and Figure 2 The injection device 5 is arranged at the lower part of the desulfurization tower 200, and includes a plurality of injection points 51 evenly distributed on the cross section of the flue gas flow direction, so as to evenly inject the gas-solid mixture into the desulfurization tower 200, so that the byproducts and the flue gas can fully contact and react quickly.

[0057] The above describes a byproduct reuse device 500 having two mutually redundant conveying modules, but the byproduct reuse device 500 is provided with only one conveying module and three or more conveying modules are also within the protection scope of the present invention. In the above embodiment, the conveying module adopts positive pressure conveying and is provided with a mixing device. As an alternative, the conveying module may also adopt negative pressure conveying without a mixing device, that is, the fan is provided between the feeding device and the injection device, and the byproduct is conveyed to the desulfurization tower in a negative pressure manner.

[0058] The byproduct reuse device 500 described above is applied in a calcium-based dry desulfurization system to transport byproducts to the desulfurization tower 200. It should be noted that the byproduct reuse device 500 can also be applied in other systems to transport powdered items.

[0059] like Figure 1 and Figure 2 As shown, in some embodiments, the desulfurizer conveying device 100 adopts a structure that is basically the same as the by-product reuse device 500, and also includes two conveying modules and a switching device. The conveying module also adopts a positive pressure conveying method. The conveying module also includes a fan 1, a mixing device 2, a feeding device 3, a powder bin 4 and an injection device 5. The desulfurizer conveying device 100 may be slightly different from the by-product reuse device 500 in details. For example, the arrangement of the injection interface 16 in the figure may be different. In terms of application, the powder bin of the desulfurizer conveying device 100 is used to hold the desulfurizer, and the powder bin of the by-product reuse device 500 is used to hold the by-product. The structure of the desulfurizer conveying device 100 will not be repeated, but in Figure 1 and Figure 2 The desulfurizing agent conveying device 100 is numbered in detail, and the control method of the desulfurizing agent conveying device 100 and the effect of the powder bin 4 not mentioned above are explained next.

[0060] The traditional desulfurization agent conveying device adopts a weightless feeding scale for feeding. Its working principle is to calculate the theoretical feeding amount according to the sulfide index and the sulfur dioxide concentration in the flue gas entering the desulfurization tower. The weightless scale then adjusts the feeding speed according to the theoretical feeding amount and the weight change of the weighing bucket. There are at least two circulation loops during the period, which causes the feeding frequency to be delayed. The delayed feeding causes the desulfurization agent fed into the desulfurization tower 200 to be inconsistent with the actual condition of the flue gas, resulting in insufficient reaction and waste of by-products. In the embodiment of the utility model, the above-mentioned spiral feeding method is adopted, and the control method is combined to reduce the influence of frequent fluctuations in the concentration of sulfur dioxide. Specifically, the control board calculates the working frequency of the driving component in the desulfurization agent conveying device 100 based on the detection results of the first detector and the sulfide index, and sends corresponding instructions to the driving component 33 to perform frequency conversion control on the feeding device 3. This control method of directly interlocking the sulfur dioxide concentration and the operating frequency of the driving component 33 of the desulfurizer conveying device 100 to form a single loop has a fast response speed, a reasonable and accurate feeding amount, and a full reaction between the by-product and sulfur dioxide, which can improve the utilization efficiency of the by-product.

[0061] In addition, the control method of the desulfurization agent delivery device is combined with the above control method of the by-product reuse device, which can effectively ensure that the sulfide concentration of the flue gas discharged from the first discharge port meets the requirements and is stable, avoiding the environmental protection penalty caused by it and solving the problem caused by the discharge of pollutants. After the two are coordinated, the raw material consumption of calcium-based ultrafine powder is saved by about 30% compared with the conventional calcium-based desulfurization system.

[0062] In industry, the silo can reach a loading capacity of 60 cubic meters / 30 tons. If a traditional open silo is used, it is convenient to pour the desulfurizer packed in tons into it, but the contact area between the top opening of the silo and the atmosphere is large, which is not only easily affected by the atmospheric humidity, but also a large amount of dust will overflow into the atmosphere. The desulfurizer conveying device 100 of the embodiment of the utility model adopts a closed silo, and a top plate is provided on the top of the closed silo. A dust removal device 10 is provided on the top plate, and the loading and unloading is completed by a suction and discharge vehicle. The desulfurizer is enclosed in the silo. On the one hand, it can prevent the desulfurizer from being blocked due to contact with moisture in the atmosphere, reduce the influence of atmospheric humidity on the material, and on the other hand, it can prevent dust from overflowing.

[0063] Continue to refer Figure 1 The gas-solid separation device 300 includes a plurality of dust collectors 3001 and dust discharge bin pumps 3002. Each dust discharge bin pump 3002 is connected to the lower end of a dust collector 3001 through a pipeline, and a gate valve for controlling the on-off is provided on the pipeline. The flue gas is separated into gas and solid by passing through the dust collector 3001. The separated gas is transported to the chimney 400 through the induced draft fan 1, and the solid is introduced into the by-product reuse device 500 through the dust discharge bin pump 3002.

[0064] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "plurality" means two or more.

[0065] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A calcium-based dry desulfurization system, characterized in that: It comprises a desulfurizing agent conveying device, a desulfurizing tower, a gas-solid separation device and a by-product reuse device, wherein the desulfurizing agent conveying device is used to spray the desulfurizing agent into the desulfurizing tower, the desulfurizing tower is connected to the gas-solid separation device, and the gas-solid separation device comprises a first discharge port for outputting gas and a second discharge port for outputting by-products; The by-product reuse device includes a conveying module, which includes a powder bin, a feeding device, a fan and an injection device. The powder bin is respectively connected to the second discharge port and the feeding device, and the feeding device is connected to the injection device. The fan is used to make the by-products in the powder bin flow to the injection device via the feeding device, and the injection device is built in the desulfurization tower.

2. The calcium-based dry desulfurization system according to claim 1, characterized in that: The feeding equipment includes a feeding shell, a screw rod and a driving component. The feeding shell includes an extrusion part. The screw rod is rotatably connected between an upper opening and a lower opening of the extrusion part. The driving component is used to drive the screw rod to rotate so that the powder is extruded from the discharge port of the extrusion part and flows to the lower opening.

3. The calcium-based dry desulfurization system according to claim 2, characterized in that: The extrusion part comprises an inner shell and an outer shell, the upper opening is formed on the inner shell, the lower opening is formed on the outer shell, a sandwich space is formed between the inner shell and the outer shell, the spiral rod is arranged on the inner shell, and a plurality of discharge ports are arranged in the circumferential direction of the inner shell so that the powder flows from the sandwich space to the lower opening; Alternatively, the extrusion portion includes an extrusion shell and a discharge plate, the two ends of the extrusion shell respectively form the upper opening and the lower opening, the discharge plate is arranged on the extrusion shell and arranged close to the lower opening, and a plurality of discharge ports are provided on the discharge plate.

4. The calcium-based dry desulfurization system according to claim 2, characterized in that: The feeding housing further comprises a funnel portion and a buffer portion, wherein the upper end of the funnel portion is connected to the powder bin, and the lower end is connected to the buffer portion, and the buffer portion is narrow at both ends and wide in the middle; The feed housing further comprises a first flow guide portion and a second flow guide portion, the two ends of the first flow guide portion are respectively connected to the extrusion portion and the second flow guide portion, the first flow guide portion is in a trumpet shape with a narrow top and a wide bottom, and the second flow guide portion is arranged obliquely relative to the vertical direction; The feeding device further comprises an air sealing structure, which is arranged at the discharge port, on the first guide part or the second guide part, and is used to prevent the airflow from flowing back into the powder bin; The powder bin includes a closed bin body, and the conveying module also includes a dust removal device, an air cannon and a vibrator. The lower end of the closed bin body is connected to the upper end of the feeding device, the dust removal device is arranged on the top plate of the closed bin body, and the air cannon and the vibrator are respectively arranged at the lower part of the closed bin body.

5. The calcium-based dry desulfurization system according to claim 1, characterized in that: The conveying module also includes a mixing device, which has a powder inlet, an air inlet and an outlet. The powder inlet is connected to the feeding device, the air inlet is connected to the fan, and the outlet is connected to the injection device.

6. The calcium-based dry desulfurization system according to claim 5, characterized in that: A dehumidification device or a heating device is arranged between the fan and the mixing device, and the dehumidification device and the heating device are used to remove moisture from the air.

7. The calcium-based dry desulfurization system according to claim 5, characterized in that: The mixing device comprises a first mixing part and a second mixing part connected to each other, wherein the first mixing part has a mixing chamber, the first mixing part is provided with an air inlet and a powder inlet connected to the mixing chamber, the second tubular mixing part has the outlet, and the middle area of ​​the second mixing part is narrower than the two ends.

8. The calcium-based dry desulfurization system according to claim 5, characterized in that: The by-product reuse device comprises a switching device and two conveying modules, wherein the switching device is respectively connected to the two conveying modules, and the switching device is connected to the pipeline between the fan and the mixing device, and the fan of any conveying module can provide power to the mixing device, the feeding device, the powder bin and the injection device of the other conveying module through the switching device; The switching device includes a first control valve, a second control valve and a third control valve, the first control valve is connected to one of the delivery modules and the second control valve, the second control valve is connected to another of the delivery modules, the third control valve is connected between the first control valve and the second control valve, and the third control valve is also connected to a purge gas source of a by-product reuse device.

9. The calcium-based dry desulfurization system according to any one of claims 5 to 8, characterized in that: The blower adopts a Roots blower; An observation device and / or a pressure difference detection device and / or a spray interface is provided on the pipeline between the mixing device and the spraying device; The injection device comprises a plurality of injection points evenly distributed on a cross section in the direction of smoke flow.

10. The calcium-based dry desulfurization system according to any one of claims 1 to 8, characterized in that: The desulfurizing agent conveying device and the by-product reuse device have the same structure, wherein the desulfurizing agent conveying device conveys calcium-based ultrafine powder, and the by-product reuse device conveys by-products.

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