Flash drying device

Abstract

According to the flash drying device, the preheater is arranged between the second dust remover and the washing device, tail gas with a certain temperature after dust removal is introduced into the preheater to serve as a heat exchange medium to preheat air sucked by the air blower, and then the tail gas after heat exchange is introduced into the washing device for washing and dust removal; according to the device, heat in tail gas with waste heat generated in the material flash drying process is utilized through the equipment, and the defect that when an existing flash drying device is used for drying materials, the heat in the tail gas is not utilized and discharged, and consequently energy is wasted is overcome; and materials deposited in the washing process can be recycled, so that resource waste is reduced.

Description

Technical Field

[0001] This application relates to the field of material drying technology, and in particular to a flash drying apparatus. Background Technology

[0002] A flash dryer is an airflow drying device with a rotary pulverizing unit. It is a highly efficient and rapid drying device that can complete the pulverization, drying, and grading of paste-like materials in one pass. Its working principle is that hot air enters tangentially at the bottom of the drying tower, forming a powerful rotating airflow under the action of an agitator. The material enters the drying tower through a screw feeder, and under the strong action of the high-speed rotating agitator, the material is dispersed by impact, friction, and shearing forces. Lumpy materials are rapidly pulverized, fully contacting, heated, and dried by the hot air. The flash dryer is a new type of continuous drying equipment integrating drying, pulverizing, and screening, particularly suitable for drying filter cake, paste, and slurry-like materials. The drying time of wet materials in the drying tower is only 5-8 seconds, with moisture evaporating instantly. The quality of the dried product is greatly affected by the drying temperature, wind speed, air volume, and pulverization speed. Furthermore, flash dryers are suitable for drying paste-like materials and filter cakes, and are widely used in the production of chemical products.

[0003] Traditional flash dryers for drying chemicals are often used in conjunction with dust collectors. The exhaust gas after dust removal is washed with water before being discharged or further treated. However, since the exhaust gas discharged from the dust collector still has a certain temperature (40~50℃), if these exhaust gases are directly washed with water, it will not only cause the temperature of the washing tower to rise and the washing effect to deteriorate, but also the heat involved in the exhaust gas will not be effectively utilized, which will lead to energy waste. Utility Model Content

[0004] This application provides a flash drying apparatus to solve the problem of energy waste caused by the unutilized emission of heat in the exhaust gas during the drying of chemicals.

[0005] This application provides a flash drying apparatus, comprising a filter press, a flash dryer, a first dust collector, a second dust collector, an exhaust fan, a preheater, and a water washing device connected in series.

[0006] The flash dryer is connected to a heater and a blower. The output end of the blower is connected to the heat exchange medium input end of the heater, and the input end of the blower is connected to the air output end of the preheater.

[0007] The washing device is also connected to the filter press;

[0008] Both the first and second dust collectors are connected to the material storage tank.

[0009] Optionally, the air inlet of the preheater is connected to an air filter.

[0010] Optionally, the washing device includes a storage tank below and a washing tower built above and connected to the storage tank.

[0011] The upper part of the scrubbing tower is equipped with a spray layer, which is connected to the liquid storage tank through a circulating pump.

[0012] Optionally, a porous baffle with a V-shaped cross-section is provided in the horizontal direction of the liquid storage tank;

[0013] A gas guide pipe is vertically installed inside the liquid storage tank. One end of the gas guide pipe is connected to the preheater, and the other end is located below the porous baffle and close to the bottom of the liquid storage tank.

[0014] Optionally, the flash dryer includes a drying chamber, the lower part of which is disposed within and connected to an air distributor;

[0015] A screw feeder is connected to the side of the drying chamber, and the screw feeder is connected to the filter press;

[0016] An agitator is installed at the bottom of the drying chamber. The agitator includes a rotating shaft, which passes through the bottom of the drying chamber and is connected to a power source through a transmission device.

[0017] The rotating shaft is a hollow structure with one end closed and the other end open. The open end is connected to the heater through a pipe. A first stirring blade is installed on the upper part of the rotating shaft, and a second stirring blade is installed on the lower part. The shape of the second stirring blade matches the bottom of the drying chamber.

[0018] The first stirring paddle includes multiple blades disposed on opposite sides of the rotating shaft, and the blades include a horizontally disposed guide tube and vertical blades disposed on the upper and lower sides of the guide tube.

[0019] One end of the guide tube is closed, and the other end is connected to the rotating shaft. Multiple through holes are also provided on one side of the guide tube, and the through holes of the guide tubes on the blades on opposite sides of the rotating shaft are located on opposite sides.

[0020] The connection between the shaft and the pipe is sealed using a dynamic seal.

[0021] Optionally, the multiple blades located on opposite sides of the rotating shaft are arranged symmetrically or staggered.

[0022] Alternatively, the transmission device may be a belt pulley or a sprocket.

[0023] The flash drying device provided in this application uses a preheater installed between the second dust collector and the washing device. The exhaust gas with a certain temperature after dust removal is introduced into the preheater as a heat exchange medium to preheat the air drawn in by the blower. The exhaust gas after heat exchange is then introduced into the washing device for washing and dust removal. The device of this application utilizes the heat in the exhaust gas with residual heat generated during the flash drying process of the material, overcoming the drawback of existing flash drying devices that waste energy due to the unutilized heat in the exhaust gas during material drying. In addition, the washing device is also connected to a filter press, which can recover the material deposited during the washing process to reduce resource waste. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a flash drying apparatus provided in one embodiment of this application;

[0026] Figure 2 This is a schematic diagram of a flash drying apparatus provided in another embodiment of this application;

[0027] Figure 3 This is a schematic diagram of the structure of a water washing device provided in an embodiment of this application;

[0028] Figure 4 This is a schematic diagram of the structure of a flash dryer provided in one embodiment of this application;

[0029] Figure 5 This is a schematic diagram of the structure of a stirrer provided in one embodiment of this application;

[0030] Figure 6 This is a schematic diagram of the structure of a first stirring impeller provided in an embodiment of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Filter press; 2. Flash dryer; 3. First dust collector; 4. Second dust collector; 5. Preheater; 6. Washing device; 7. Heater; 8. Blower; 9. Material storage tank; 21. Drying chamber; 22. Air distributor; 23. Screw feeder; 24. Rotary shaft; 41. Exhaust fan; 51. Air filter; 61. Liquid storage tank; 62. Washing tower; 63. Circulating pump; 241. First agitator; 242. Second agitator; 611. Porous baffle; 612. Air guide pipe; 621. Spray layer; 2411. Blade; 24111. Guide tube; 24112. Blade. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0034] like Figure 1 As shown, this application provides a flash drying device, including a filter press 1, a flash dryer 2, a first dust collector 3, a second dust collector 4, an exhaust fan 41, a preheater 5, and a water washing device 6 connected in series.

[0035] The flash dryer 2 is connected to the blower 8 via the heater 7. The output end of the blower 8 is connected to the heat exchange medium input end of the heater 7, and the input end of the blower 8 is connected to the air output end of the preheater 5.

[0036] The washing device 6 is also connected to the filter press 1;

[0037] Both the first dust collector 3 and the second dust collector 4 are connected to the material storage tank 9.

[0038] In operation, the filter cake obtained after filtration by filter press 1 is transferred to flash dryer 2. Outside air, after heat exchange with exhaust gas via preheater 5, is introduced into heater 7 by blower 8 to form hot air, which is then introduced into flash dryer 2. Simultaneously, the stirring device of flash dryer 2 is activated for stirring. The lumpy material falls downwards under gravity. Due to the inverted cone structure at the bottom of the dryer, the airflow velocity is high, ensuring the lumpy material is in a good fluidized state and surrounded by hot air. During this process, the material is crushed and blown up by the high-speed rotating hot airflow from the bottom, forming a relatively stable fluidized bed in the drying chamber. Heat and mass transfer occur between the material and the hot air, and most of the moisture evaporates during this stage. Materials with high moisture content and small specific surface area have high density and fall downwards in the drying chamber. Due to the high air velocity at the bottom, the falling velocity becomes zero after settling to a certain position, at which point gravity and buoyancy are balanced. After further crushing and drying, buoyancy exceeds gravity, and the material begins to move upwards, exiting the dryer after grading. The flash dryer 2 is equipped with a grading ring. As the material rises with the airflow, it is subjected to centrifugal force, which increases the rotation radius of large, undried pieces of material. When the rotation radius exceeds the radius of the grading ring, the material is blocked in the drying chamber until it meets the requirements and can then pass through the grading ring and be discharged from the dryer.

[0039] The fine particulate material discharged from the flash dryer 2 first enters the first dust collector 3 to separate most of the fine particulate material from the hot air. The separated material is stored in the material storage tank 9. The separated hot air still contains a small amount of fine particulate material, which is then further separated by the second dust collector 4 for gas-solid separation and dust removal. The separated material is stored in the material storage tank 9. The tail gas obtained from the separation still has a certain amount of heat (temperature about 40~50℃). This tail gas is transferred to the preheater 5 as a heat exchange medium to preheat the air drawn in by the blower 8, so as to reduce the energy loss of the heater 7. The tail gas after heat exchange still contains a small amount of fine particles. It is then passed into the water washing device 6 for cooling and water washing dust removal treatment. The washed gas can be discharged.

[0040] The flash drying device provided in this application uses a preheater 5 installed between the second dust collector 4 and the washing device 6. The exhaust gas with a certain temperature after dust removal is passed into the preheater 5 as a heat exchange medium to preheat the air drawn in by the blower 8. The exhaust gas after heat exchange is then passed into the washing device 6 for washing and dust removal. The device of this application utilizes the heat in the exhaust gas with residual heat generated during the flash drying process of the material, overcoming the drawback of existing flash drying devices that waste energy due to the unutilized heat in the exhaust gas during material drying. In addition, the washing device 6 is also connected to the filter press 1, which can recover the material deposited during the washing process to reduce resource waste.

[0041] like Figure 2 As shown, optionally, the air inlet of the preheater 5 is connected to the air filter 51.

[0042] In this application, an air filter 51 is provided to filter dust and other particles in the air, thereby making the air entering the preheater 5 clean. This not only avoids introducing impurities into the material and affecting the purity of the material, but also reduces the accumulation of dirt in the cavity of the equipment after long-term operation, thereby extending the cleaning cycle.

[0043] like Figure 3 As shown, optionally, the washing device 6 includes a liquid storage tank 61 below and a washing tower 62 built above and connected to the liquid storage tank 61.

[0044] A spray layer 621 is provided in the upper part of the washing tower 62, and the spray layer 621 is connected to the liquid storage tank 61 through the circulation pump 63.

[0045] In this application, during use, these materials are separated from the exhaust gas after being washed with clean water in the storage tank 61. Since the materials are insoluble in water (the materials in this application are organic compounds that are insoluble in water), they will accumulate and settle in the storage tank 61. The exhaust gas washed in the storage tank 61 then enters the washing tower 62. The circulating pump 63 circulates the water in the storage tank 61 to the spray layer 621 and sprays it down to wash the exhaust gas again. The washed exhaust gas can be discharged after being demisted by the demister at the top of the tower.

[0046] The material accumulated in the storage tank 61 is transferred to the filter press 1 for dewatering and then sent to the flash dryer 2 for drying.

[0047] like Figure 3 As shown, optionally, a porous baffle 611 with a V-shaped cross-section is provided in the liquid storage tank 61 along the horizontal direction;

[0048] A gas guide pipe 612 is vertically installed inside the liquid storage tank 61. One end of the gas guide pipe 612 is connected to the preheater 5, and the other end is located below the porous baffle 611 and close to the bottom of the liquid storage tank 61.

[0049] The exhaust gas is input through the vent pipe 612 and then flows into the liquid storage tank 61. It exits below the V-shaped porous baffle 611. Since the exhaust gas contains a small amount of particulate matter, the V-shaped porous baffle 611 in the liquid storage tank 61 prevents the agitation of the upper liquid layer, thus avoiding the undesirable consequence of material settling at the bottom of the tank. Furthermore, the inclined surface of the V-shaped porous baffle 611 facilitates the drainage of sediment deposited on the baffle through the holes, preventing it from settling on the baffle.

[0050] like Figures 4-6As shown, optionally, the flash dryer 2 includes a drying chamber 21, the lower part of which is disposed in and connected to the air distributor 22.

[0051] A screw feeder 23 is connected to the side of the drying chamber 21, and the screw feeder 23 is connected to the filter press 1;

[0052] An agitator is installed at the bottom of the drying chamber 21. The agitator includes a rotating shaft 24, which passes through the bottom of the drying chamber 21 and is connected to a power source through a transmission device.

[0053] The rotating shaft 24 is a hollow structure with one end closed and the other end open. The open end is connected to the heater 7 through a pipe. A first stirring paddle 241 is provided on the upper part of the rotating shaft 24, and a second stirring paddle 242 is provided on the lower part. The shape of the second stirring paddle 242 matches the bottom of the drying chamber 21.

[0054] The first stirring paddle 241 includes a plurality of blades 2411 disposed on opposite sides of the rotating shaft 24. Each blade 2411 includes a horizontally disposed guide tube 24111 and vertical blades 24112 disposed on the upper and lower sides of the guide tube 24111.

[0055] One end of the guide tube 24111 is closed, and the other end is connected to the rotating shaft 24. Multiple through holes are also provided on one side of the guide tube 24111, and the through holes of the guide tube 24111 on the blades 2411 on opposite sides of the rotating shaft 24 are located on opposite sides.

[0056] The connection between the rotating shaft 24 and the pipeline is sealed by a dynamic seal.

[0057] In this application, the filter cake obtained after being pressed by the filter press 1 is fed into the drying chamber 21 through the screw feeder 23 on one side of the drying chamber 21. At the same time, outside air is filtered by the air filter 51, and after exchanging heat with the exhaust gas in the preheater 5, it is introduced into the heater 7 by the blower 8 to heat the air into hot air. Part of the hot air enters the air distributor 22 and enters the drying chamber 21 through the air distributor 22, while the other part enters the rotating shaft 24 and is discharged into the drying chamber 21 through the duct connected to the rotating shaft 24. At the same time, the power source is started to drive the rotating shaft 24 to rotate through the transmission device (such as a sprocket or pulley), which in turn drives the first stirring paddle 241 and the second stirring paddle 242 to rotate, stirring, dispersing, and breaking the material (i.e., the filter cake) input into the drying chamber 21 to produce a dispersion effect. At the same time, the hot air entering the drying chamber 21 is in a highly turbulent state due to the guidance of the air distributor 22, so the hot air and the material can be mixed quickly. Simultaneously, the lumpy material falls downwards under gravity. Due to the inverted cone structure at the bottom of the dryer, the airflow velocity is very high, ensuring the lumpy material remains in a good fluidized state and is surrounded by hot air. During this process, after the material is crushed, it is blown up by the high-speed rotating hot airflow from the bottom, forming a relatively stable fluidized bed in the drying chamber. Heat and mass transfer occur between the material and the hot air during the drying process, and most of the moisture evaporates in this stage. Materials with high moisture content and small specific surface area have high density and fall downwards in the drying chamber. Due to the high air velocity at the bottom, the falling velocity becomes zero after settling to a certain position, at which point gravity and buoyancy are balanced. After further crushing and drying, buoyancy exceeds gravity, and the material begins to move upwards, exiting the dryer after grading.

[0058] In this application, the through holes of the guide tubes 24111 on the blades 2411 on opposite sides of the rotating shaft 24 are located on opposite sides. This way, when hot air is discharged from the through holes, it can generate a counter-thrust force on the blades 2411 (the counter-thrust force should be in the same direction as the rotation of the rotating shaft 24, otherwise it will increase the resistance), thereby reducing the resistance of the rotation of the rotating shaft 24, which is beneficial to extending the service life of the equipment. In addition, the discharge of hot air through the guide tubes 24111 can also effectively enhance the mixing of hot air and materials, which is beneficial to the drying of materials.

[0059] Such as 5 and Figure 6 As shown, optionally, the multiple blades 2411 disposed on opposite sides of the rotating shaft 24 are arranged symmetrically or staggered.

[0060] In this application, when multiple blades 2411 are arranged symmetrically, the stability of stirring can be enhanced; when they are arranged in an alternating manner, the shearing and crushing ability of the blades 2411 on the material can be improved.

[0061] Alternatively, the transmission device may be a belt pulley or a sprocket.

[0062] In this application, the use of belt pulleys or sprockets is characterized by ease of implementation and stable transmission.

[0063] The working process of a flash drying device is as follows:

[0064] In operation, the filter cake obtained after filtration by the filter press 1 (taking a material insoluble in water as an example) is fed into the drying chamber 21 through the screw feeder 23 on one side of the drying chamber 21. At the same time, outside air is filtered by the air filter 51, and after exchanging heat with the exhaust gas in the preheater 5, it is introduced into the heater 7 by the blower 8 to heat the air into hot air. Part of the hot air enters the air distributor 22 and enters the drying chamber 21 through the air distributor 22, while the other part enters the rotating shaft 24 and is discharged into the drying chamber 21 through the duct connected to the rotating shaft 24. At the same time, the power source is started to drive the rotating shaft 24 to rotate through the transmission device (such as a sprocket or pulley), which in turn drives the first stirring paddle 241 and the second stirring paddle 242 to rotate, stirring, dispersing, and breaking the material (i.e., the filter cake) input into the drying chamber 21 to produce a dispersion effect. At the same time, the hot air entering the drying chamber 21 is in a highly turbulent state due to the guidance of the air distributor 22, so the hot air and the material can be mixed quickly. Simultaneously, the lumpy material falls downwards under gravity. Due to the inverted cone structure at the bottom of the dryer, the airflow velocity is very high, ensuring that the lumpy material is in a good fluidized state and surrounded by hot air. During this process, after the material is crushed, it is blown up by the high-speed rotating hot airflow from the bottom, forming a relatively stable fluidized bed in the drying chamber. The drying process involves heat and mass transfer between the material and the hot air, and most of the moisture evaporates during this stage. Materials with high moisture content and small specific surface area have high density and fall downwards in the drying chamber. Due to the high air velocity at the bottom, the falling velocity becomes zero after settling to a certain position, at which point gravity and buoyancy are balanced. After further crushing and drying, buoyancy exceeds gravity, and the material begins to move upwards, exiting the dryer after grading. A grading ring is set at the top of the drying chamber 21. As the material rises with the airflow, due to the centrifugal force, the rotation radius of large, undried materials increases. When the rotation radius is greater than the radius of the grading ring, the material is blocked in the drying chamber until it meets the requirements before it can be discharged from the dryer through the grading ring.

[0065] The fine particulate material discharged from the flash dryer 2 first enters the first dust collector 3 to separate most of the fine particulate material from the hot air. The separated material is stored in the material storage tank 9. The separated hot air still contains a small amount of fine particulate material, which is then further separated by the second dust collector 4 for gas-solid separation and dust removal. The separated material is stored in the material storage tank 9. The tail gas obtained after separation still has a certain amount of heat (temperature about 40~50℃). This tail gas is transferred to the preheater 5 as a heat exchange medium to preheat the air drawn by the blower 8, so as to reduce the energy loss of the heater 7. The tail gas after heat exchange still contains a small amount of fine particles, so it is passed into the water washing device 6 for cooling and water washing dust removal treatment.

[0066] During treatment in the washing device 6, the exhaust gas is input through the gas guide pipe 612 and then into the storage tank 61. It is discharged from below the V-shaped porous baffle 611. Since the exhaust gas also contains a small amount of material particles, these particles are separated from the exhaust gas after being washed with clean water in the storage tank 61. Because the material is insoluble in water (the material in this application is an organic compound that is insoluble in water), it will accumulate and precipitate in the storage tank 61. Since the storage tank 61 is equipped with a V-shaped porous baffle 611, it can prevent the agitation of the upper liquid from causing the material to have difficulty settling at the bottom of the tank. The exhaust gas washed in the storage tank 61 then enters the washing tower 62. The circulating pump 63 circulates the water in the storage tank 61 to the spray layer 621 and sprays it down to wash the exhaust gas again. The washed exhaust gas can be discharged after being demisted by the demister at the top of the tower.

[0067] The material accumulated in the storage tank 61 is transferred to the filter press 1 for dewatering and then sent to the flash dryer 2 for drying.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A flash drying apparatus, characterized by, The filter press (1), the flash dryer (2), the first dust collector (3), the second dust collector (4), the air extractor (41), the preheater (5) and the water washing device (6) are sequentially connected in series. The flash dryer (2) is connected with the air blower (8) through the heater (7), the output end of the air blower (8) is connected with the heat exchange medium input end of the heater (7), and the input end of the air blower (8) is connected with the air output end of the preheater (5). The water washing device (6) is also connected with the filter press (1). The first dust collector (3) and the second dust collector (4) are connected with the material storage tank (9).

2. The flash drying apparatus of claim 1, wherein The air input end of the preheater (5) is connected with the air filter (51).

3. The flash drying apparatus of claim 1, wherein The water washing device (6) comprises a liquid storage tank (61) below and a washing tower (62) established above the liquid storage tank (61) and in communication with the liquid storage tank (61). A spray layer (621) is arranged at the upper portion of the washing tower (62), and the spray layer (621) is in communication with the liquid storage tank (61) through a circulating pump (63).

4. The flash drying apparatus of claim 3, wherein A plurality of V-shaped porous partitions (611) are arranged in the liquid storage tank (61) in the horizontal direction. A gas guide pipe (612) is vertically arranged in the liquid storage tank (61), one end of the gas guide pipe (612) is connected with the preheater (5), the other end is arranged below the porous partition (611) and close to the bottom of the liquid storage tank (61).

5. The flash drying apparatus of claim 1, wherein The flash dryer (2) comprises a drying bin body (21), a stirrer is arranged at the bottom of the drying bin body (21), the stirrer comprises a rotating shaft (24), the rotating shaft (24) penetrates the bottom of the drying bin body (21) and is connected with a power source through a transmission device. The rotating shaft (24) is a hollow structure with one end closed and the other end open, the open end is connected with the heater (7) through a pipeline, a first stirring paddle (241) is arranged at the upper portion of the rotating shaft (24), and a second stirring paddle (242) is arranged at the lower portion of the rotating shaft (24), the second stirring paddle (242) is matched with the shape of the bottom of the drying bin body (21). The first stirring paddle (241) comprises a plurality of paddle blades (2411) arranged on the opposite sides of the rotating shaft (24), the paddle blade (2411) comprises a horizontal pipeline (24111) and vertical blades (24112) arranged on the upper and lower sides of the pipeline (24111). One end of the pipeline (24111) is closed, the other end is in communication with the rotating shaft (24), a plurality of through holes are formed in one side of the pipeline (24111), and the through holes formed in the pipelines on the paddle blades (2411) on the opposite sides of the rotating shaft (24) are located on different sides. The connection between the rotating shaft (24) and the pipeline is sealed in a dynamic sealing mode.

6. The flash drying apparatus of claim 5, wherein The plurality of paddle blades (2411) arranged on the opposite sides of the rotating shaft (24) are symmetrically arranged or staggered.

7. The flash drying apparatus of claim 5, wherein The transmission device is a belt pulley or a chain wheel.

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