A nitrogen internal circulation flash drying system

Abstract

The utility model discloses a nitrogen internal circulation flash drying system, including the air blower, heat exchanger, flash drying machine, cyclone separator, dust remover, induced fan, spray tower and surface cooler that are connected in proper order through pipeline, and the gas export of surface cooler is communicated with the air inlet of air blower through pipeline, forms an internal circulation passageway, the bottom of spray tower still is provided cooling coil, and the gas outlet of spray tower is arranged at the top, and the gas outlet is communicated with the gas inlet of surface cooler through pipeline, the surface cooler includes the liquid outlet, and the liquid outlet is communicated with the tower bottom of spray tower through reflux pipeline, the utility model discloses the liquid outlet of surface cooler is communicated with the tower bottom of spray tower through reflux pipeline, and the tower bottom of spray tower is provided cooling coil, and the organic solvent of whole system is concentrated in the spray tower bottom, and the liquid of spray tower bottom is recycled or is sent storage tank storage after exceeding the limit through the spray pump, therefore the utility model not only has nitrogen internal circulation, and the organic solvent also realizes the recycling use.

Description

Technical Field

[0001] This utility model relates to a drying system, specifically a nitrogen internal circulation flash drying system. Background Technology

[0002] Flash drying equipment is a continuous drying device that integrates crushing, drying, and screening functions. It is suitable for drying paste-like, slurry-like, and filter cake-like materials. Its drying principle involves hot air entering tangentially at the bottom of the dryer, forming a powerful rotating airflow under the action of an agitator. Materials, such as pastes, enter the dryer through a screw feeder. Under the strong action of the high-speed rotating agitator, the material is dispersed due to impact, friction, and shear stress. Lumpy materials are rapidly crushed, fully contacting, heated, and dried by the hot air. The dehydrated dry material rises with the hot airflow and is recovered by a cyclone separator and dust collector.

[0003] Flash drying equipment typically includes heaters, feeders, mixing and crushing systems, classifiers, cyclone separators, bag filters, and fans.

[0004] Regarding flash drying equipment, Chinese patent document CN 223020702 U (application number 202422182398.7) discloses a flash drying device with a dispersion mechanism, including a dryer, a base fixedly connected to the bottom end of the dryer, a screw feeder arranged on the right side of the dryer, a feed hopper arranged at the top end of the screw feeder, a first motor arranged at the bottom end of the screw feeder, a conical disk arranged at the bottom inside the dryer, and limiting components that can accelerate the dispersion of materials fixedly connected to the left and right sides of the bottom inside the dryer.

[0005] For example, Chinese patent document CN 207933310 U (application number 201820149560.7) discloses a nitrogen closed-loop circulating acetic acid recovery flash drying system, including a nitrogen source, a heater, an explosion-proof blower, a flash dryer, a screw feeder, a cyclone separator, a heat exchanger, a condenser, a solvent recovery tank, and a first cryogenic crystallizer and a second cryogenic crystallizer arranged in parallel. The nitrogen source, heater, explosion-proof blower, flash dryer, and cyclone separator are sequentially and sealed together by pipelines. The gas mixed with gaseous acetic acid discharged from the outlet of the cyclone separator is cooled by the heat exchanger and then enters the condenser, where the gas mixed with gaseous acetic acid is condensed. The condenser is connected to the solvent recovery tank, so that the gaseous acetic acid is cooled before entering the solvent recovery tank. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a safe, environmentally friendly, and stable nitrogen internal circulation flash drying system.

[0007] The technical solution for achieving the purpose of this utility model is a nitrogen internal circulation flash drying system, comprising a blower, a steam heat exchanger, a flash dryer, a cyclone separator, a dust collector, an induced draft fan, a spray tower, and a surface cooler connected in sequence by pipelines. The gas outlet of the surface cooler is connected to the air inlet of the blower through a pipeline, forming an internal circulation path. A nitrogen replenishment pipeline is installed on the pipeline between the gas outlet of the surface cooler and the air inlet of the blower. A cooling coil is also installed at the bottom of the spray tower, and the gas outlet of the spray tower is located at the top, connected to the gas inlet of the surface cooler through a pipeline. The surface cooler includes a liquid outlet, which is connected to the bottom of the spray tower through a return pipeline.

[0008] The feed inlet of the flash dryer is connected to the discharge outlet of the feeder; the feeder includes a frame, a hopper, a feeding auger and an arch breaking device, the hopper is placed on the frame and a feeding port is provided on the top of the hopper.

[0009] The feeding auger includes a motor, a rotating shaft, and spiral blades. The spiral blades and a section of the rotating shaft connecting the spiral blades are located at the bottom of the hopper.

[0010] The arch-breaking device includes an arch-breaking motor, a rotating shaft, and a stirring blade. The stirring blade and a section of the rotating shaft connecting the stirring blade are located inside the hopper. The stirring blade is located between the top feeding port of the hopper and the bottom feeding auger.

[0011] The arch-breaking device includes two units, with the rotating shafts of the two arch-breaking devices and the corresponding first and second blades respectively set between the top feeding port of the hopper and the bottom feeding auger.

[0012] A vibrator and an inspection port are provided on the outer side of the hopper.

[0013] The top of the dust collector is also connected to a nitrogen backflush pipe, which is connected to a nitrogen storage tank.

[0014] A spray pump is also installed outside the spray tower. The inlet of the spray pump is connected to the bottom of the tower through a pipe, and the outlet is connected to the spray pipe. The outlet of the spray pipe is located above the packing inside the tower.

[0015] An oxygen content analyzer is also installed on the pipe between the gas outlet of the surface cooler and the air inlet of the blower.

[0016] A valve is installed on the nitrogen replenishment pipeline, and the oxygen content analyzer is interlocked with the valve on the nitrogen replenishment pipeline.

[0017] This utility model has positive effects: This invention connects the outlet of the surface cooler to the bottom of the spray tower via a reflux pipe. A cooling coil is installed at the bottom of the spray tower to concentrate the organic solvent of the entire system. The liquid at the bottom of the spray tower is circulated and reused via a spray pump. Therefore, this invention achieves both nitrogen internal circulation and organic solvent recycling. Connecting the outlet of the surface cooler to the bottom of the spray tower via the reflux pipe ensures the required amount of spray liquid for spraying, and also allows for direct pumping and pipeline transfer to a storage tank for reuse when the spray liquid at the bottom exceeds the limit.

[0018] This invention interlocks the oxygen content analyzer with the valve of the nitrogen replenishment pipeline. A set oxygen content value is established; if the oxygen content exceeds this value, the valve automatically opens to replenish nitrogen and reduce the oxygen content. If the oxygen content falls below the set value, the valve closes, keeping the nitrogen circulation system outside the explosion limits. This solves the explosion problem of dust and flammable gases in flash drying. Simultaneously, the protection of the inert gas prevents material oxidation, improving quality. Furthermore, it significantly reduces employee workload and improves the on-site working environment, as the material in the ton bag is added all at once, and the feeding auger provides continuous, closed-loop feeding. Therefore, this invention is a safe and environmentally friendly flash drying system. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the nitrogen internal circulation flash drying system of this utility model.

[0020] Figure 2 for Figure 1 A schematic diagram of the internal structure of the feeder in the diagram.

[0021] Figure 3 From Figure 2 The diagram shows the internal structure of the feeder when viewed from the left.

[0022] The markings in the above figures are as follows: 1. Blower; 2. Steam heat exchanger; 3. Feeder; 3-1. Hopper; 3-1-1. Vibrator; 3-1-2. Inspection port; 3-1-3. Weighing module; 3-1-3. Feeding auger; 3-2. Rotating shaft; 3-2-1. Spiral blade; 3-2-2. Discharge end; 3-2-3. First blade; 3-3. Second blade; 3-4. Flash dryer; 4. Cyclone separator; 5. Dust collector; 6. Nitrogen backflushing pipe; 6-1. Exhaust fan; 7. Spray tower; 8. Cooling coil; 9. Spray pump; 10. Surface cooler; 11. Return pipe; 11-1. Nitrogen balance tank; 12. Pipe connecting to incinerator; 12-1. Oxygen content analyzer; 13. Nitrogen replenishment pipe; 14. Valve; 14-1. Detailed Implementation

[0023] The following describes some of the possible embodiments of this utility model, intended to provide a basic understanding of the utility model, and is not intended to identify the key or decisive elements of the utility model or limit the scope of protection to be provided. It is readily understood that, based on the technical solution of this utility model, those skilled in the art can propose other interchangeable implementations without changing the essential spirit of the utility model. Therefore, the following specific embodiments are merely illustrative examples of the technical solution of this utility model and should not be considered as the entirety of this utility model or as a limitation or restriction of the technical solution of this utility model.

[0024] (Example 1) See Figures 1 to 3 The nitrogen internal circulation flash drying system of this embodiment includes a blower 1, a steam heat exchanger 2, a feeder 3, a flash dryer 4, a cyclone separator 5, a dust collector 6, an induced draft fan 7, a spray tower 8, a cooling coil 9, a spray pump 10, a surface cooler 11, a nitrogen balance tank 12, an oxygen content analyzer 13, a nitrogen replenishment pipeline 14, and various connecting pipelines. The blower 1, the steam heat exchanger 2, the flash dryer 4, the cyclone separator 5, the dust collector 6, the induced draft fan 7, the spray tower 8, and the surface cooler 11 are connected in sequence by pipelines, and the gas outlet of the surface cooler 11 is connected to the air inlet of the blower 1 by a pipeline, forming an internal circulation path.

[0025] A nitrogen replenishment pipe 14 is installed on the pipeline between the gas outlet of the surface cooler 11 and the air inlet of the blower 1. The nitrogen replenishment pipe 14 is connected to a nitrogen storage tank (not shown in the figure), and nitrogen is replenished into the internal circulation path through the nitrogen storage tank and the nitrogen replenishment pipe 14. A valve 14-1 is installed on the nitrogen replenishment pipe 14.

[0026] The air outlet of the blower 1 is connected to the air inlet of the steam heat exchanger 2, and the air outlet of the steam heat exchanger 2 is connected to the air inlet of the flash dryer 4 through a pipe.

[0027] The steam heat exchanger 2 includes a steam inlet and a steam outlet. The nitrogen gas entering the steam heat exchanger 2 exchanges heat with the hot steam and becomes high-temperature nitrogen gas, which enters the bottom of the flash dryer 4 tangentially.

[0028] The discharge port of the feeder 3 is connected to the inlet of the flash dryer 4.

[0029] See Figure 2 and Figure 3 The feeder 3 includes a frame, a hopper 3-1, a feeding auger 3-2, and an arch-breaking device, with the hopper 3-1 placed on the frame.

[0030] The inner cavity of the hopper 3-1 is approximately triangular prism-shaped. The top of the hopper 3-1 is equipped with a cover, and the feeding port of the cover is located directly above the hopper. The outer side of the hopper 3-1 is equipped with a vibrator 3-1-1 and an inspection port 3-1-2. The vibrator 3-1-1 vibrates to prevent the material from sticking to the wall and not flowing down. The inspection port 3-1-2 is used for the inspection of the internal structure of the hopper.

[0031] See Figure 3 The feeding auger 3-2 includes a motor (not shown in the figure), a rotating shaft 3-2-1, and spiral blades 3-2-2. The motor is located outside the hopper 3-1. The rotating shaft 3-2-1 passes through the hopper 3-1, and both ends extend out of the hopper 3-1 and are fixed to the outside of the hopper 3-1 by bearings. The spiral blades 3-2-2 are fixed to the rotating shaft 3-2-1. Most of the spiral blades 3-2-2 are located in the hopper 3-1, and the ends of the spiral blades 3-2-2 are located inside the discharge end 3-2-3 outside the hopper 3-1. The discharge end 3-2-3 includes a housing, and the discharge port of the housing is connected to the inlet of the flash dryer 4. Alternatively, in some embodiments, the discharge end 3-2-3 extends into the flash dryer 4. The discharge port is located on the downward-facing plate of the housing.

[0032] The arch-breaking device includes an arch-breaking motor (not shown in the figure), a rotating shaft, and a stirring blade. The output shaft of the arch-breaking motor is connected to the rotating shaft. The arch-breaking motor is located outside the hopper 3-1, and both ends of the rotating shaft are fixed to the outside of the hopper 3-1 by bearings. The stirring blade is fixed on the rotating shaft and located inside the hopper 3-1.

[0033] In this embodiment, two arch-breaking devices are provided. The rotating shafts of the two arch-breaking devices and the corresponding stirring blades (the first blade 3-3 and the second blade 3-4, respectively) are set at the top and bottom between the top feeding port and the bottom feeding auger 3-2. The two arch-breaking devices can prevent material bridging and breakage.

[0034] Furthermore, the hopper 3-1 also includes a weighing module 3-1-3, which is electrically connected to the control system. The control system is electrically connected to the motor of the feeding auger 3-2. The weighing module 3-1-3 can detect the weight of the material in the hopper in real time. For example, when the material in the hopper 3-1 is less than 200 kg, the motor of the feeding auger 3-2 stops working, ensuring that the material is kept at a certain height to isolate it from air and prevent air from being drawn in and damaging the entire nitrogen circulation system.

[0035] The discharge end 3-2-3 of the feeding auger 3-2 is connected to the inlet of the flash dryer 4, which is located above the bottom air inlet. The discharge outlet of the flash dryer 4 is connected to the inlet of the cyclone separator 5, which in turn is connected to the inlet of the dust collector 6 (e.g., a bag filter). The air outlet of the dust collector 6 is connected to the air inlet of the induced draft fan 7 via a pipe, and the air outlet of the induced draft fan 7 is connected to the space below the bottom packing of the spray tower 8 via a pipe.

[0036] The top of the dust collector 6 is also connected to a nitrogen backflush pipe 6-1, which is connected to a nitrogen storage tank.

[0037] The bottom of the spray tower 8 is also equipped with a cooling coil 9, which includes an inlet and an outlet for the coolant, both located outside the spray tower 8. The cooling coil 9 is used to cool the high-temperature spray liquid falling to the bottom of the tower. The cooling coil 9 is located below the air inlet at the bottom of the spray tower 8.

[0038] A spray pump 10 is also installed outside the spray tower 8. The inlet of the spray pump 10 is connected to the bottom of the tower through a pipe, and the outlet is connected to the spray pipe. The outlet of the spray pipe is located above the packing inside the tower, so that the spray pump 10 draws the liquid from the bottom of the tower and transports it to the top of the packing inside the tower through the pipe.

[0039] The air outlet of the spray tower 8 is located at the top, and the air outlet is connected to the gas inlet of the surface cooler 11 through a pipe.

[0040] The surface cooler 11 includes an inlet and an outlet for the refrigerant, and a coil between the inlet and the outlet.

[0041] The surface cooler 11 also includes a liquid outlet, which is connected to the bottom of the spray tower 8 via a reflux pipe 11-1. Thus, the solvent / spray liquid carried out by the high-temperature gas is cooled by the surface cooler 11 and flows out from the liquid outlet, and is sent to the bottom of the spray tower 8 via the reflux pipe 11-1.

[0042] A nitrogen balance tank 12 and an oxygen content analyzer 13 are also installed on the pipe between the gas outlet of the surface cooler 11 and the air inlet of the blower 1.

[0043] The nitrogen balance tank 12 is preset with a pressure value (set pressure 50Pa). If the pressure value is exceeded, the excess nitrogen in the system will be sent to the incinerator for treatment through the incinerator connection pipe 12-1 of the nitrogen balance tank.

[0044] The oxygen content analyzer 13 is interlocked with the valve 14-1 on the nitrogen replenishment pipeline 14. That is, an oxygen content value is set. If the oxygen content exceeds the value, the valve 14-1 will automatically open to replenish nitrogen to reduce the oxygen content. If the oxygen content is lower than the set value, the valve will automatically close.

[0045] The flash drying system of this utility model is filled with nitrogen through nitrogen replenishment pipe 14. The wet material to be dried, packaged in ton bags, is added to the hopper 3-1 of the feeder 3 at one time. After being dispersed by the first blade 3-3 and the second blade 3-4, the material is sent into the flash dryer 4 through the feeding auger 3-2. The induced draft fan 7 and the blower 1 are turned on. Nitrogen gas is heated by the steam heat exchanger 2 and then enters the flash dryer 4. The organic matter in the material is dried and volatilized in the hot nitrogen. The powdered material and the hot nitrogen containing organic solvent enter the cyclone separator 5 and the dust collector 6. The powdered material is collected. The hot air containing high concentration of organic matter enters the spray tower 8 with the circulating spray pump 10 for spray absorption (the circulating spray liquid is the same solvent carried by the material). The circulating liquid at the bottom of the tower is cooled by the cooling coil 9. The air outlet of the spray tower 8 is cooled by the surface cooler 11 with the refrigerant flowing in the coil. The cooled solvent flows back into the spray tower 8 through the return pipe 11-1, concentrating the organic solvent of the entire system at the bottom of the spray tower. Furthermore, the spray tower 8 has an automatic liquid level controller. Since the solvent at the bottom of the tower has been cooled, the liquid at the bottom of the tower can be pumped directly to the workshop storage tank for reuse after it exceeds the liquid level. The air cooled by the surface cooler 11 enters the blower 1 through the pipe and is circulated repeatedly in the system.

Claims

1. A nitrogen internal circulation flash drying system, characterized in that: The system includes a blower (1), a steam heat exchanger (2), a flash dryer (4), a cyclone separator (5), a dust collector (6), an induced draft fan (7), a spray tower (8), and a surface cooler (11) connected in sequence by pipes. The gas outlet of the surface cooler (11) is connected to the air inlet of the blower (1) by a pipe to form an internal circulation path. A nitrogen replenishment pipe (14) is installed on the pipe between the gas outlet of the surface cooler (11) and the air inlet of the blower (1). A cooling coil (9) is also installed at the bottom of the spray tower (8). The gas outlet of the spray tower (8) is located at the top and is connected to the gas inlet of the surface cooler (11) by a pipe. The surface cooler (11) includes a liquid outlet, which is connected to the bottom of the spray tower (8) by a return pipe (11-1).

2. The nitrogen internal circulation flash drying system according to claim 1, characterized in that: The feed inlet of the flash dryer (4) is connected to the discharge outlet of the feeder (3); the feeder (3) includes a frame, a hopper (3-1), a feeding auger (3-2) and an arch breaking device. The hopper (3-1) is placed on the frame and a feeding port is provided on the top of the hopper (3-1). The feeding auger (3-2) includes a motor, a rotating shaft (3-2-1) and a spiral blade (3-2-2). The spiral blade (3-2-2) and a section of the rotating shaft (3-2-1) connecting the spiral blade (3-2-2) are located at the bottom of the hopper (3-1). The arch-breaking device includes an arch-breaking motor, a rotating shaft, and a stirring blade. The stirring blade and a section of the rotating shaft connecting the stirring blade are located inside the hopper (3-1). The stirring blade is located between the top feeding port of the hopper (3-1) and the bottom feeding auger (3-2).

3. The nitrogen internal circulation flash drying system according to claim 2, characterized in that: The arch-breaking device includes two units. The rotating shafts of the two arch-breaking devices and the corresponding first blade (3-3) and second blade (3-4) are set at the top and bottom of the feeding port at the top of the hopper (3-1) and the feeding auger (3-2) at the bottom.

4. The nitrogen internal circulation flash drying system according to claim 2, characterized in that: A vibrator (3-1-1) and an inspection port (3-1-2) are installed on the outer side of the hopper (3-1).

5. The nitrogen internal circulation flash drying system according to claim 1, characterized in that: The top of the dust collector (6) is also connected to a nitrogen backflush pipe (6-1), which is connected to a nitrogen storage tank.

6. The nitrogen internal circulation flash drying system according to claim 1, characterized in that: A spray pump (10) is also installed outside the spray tower (8). The inlet of the spray pump (10) is connected to the bottom of the tower through a pipe, and the outlet is connected to the spray pipe. The outlet of the spray pipe is located above the packing inside the tower.

7. The nitrogen internal circulation flash drying system according to claim 1, characterized in that: An oxygen content analyzer (13) is also installed on the pipe between the gas outlet of the surface cooler (11) and the air inlet of the blower (1).

8. The nitrogen internal circulation flash drying system according to claim 7, characterized in that: A valve (14-1) is installed on the nitrogen replenishment pipeline (14), and the oxygen content analyzer (13) is interlocked with the valve (14-1) on the nitrogen replenishment pipeline (14).

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