Continuous dynamic closed cycle drying system and method

Abstract

The invention belongs to the technical field of marine biological resource processing equipment, and particularly relates to a continuous dynamic closed-loop circulation drying system and method.The system comprises a control system, a circulation ventilation pipeline, a nitrogen supply mechanism, a drying tower, a drying main machine, a conveying mechanism, a raw material container, a grading screening mechanism, a heat energy recycling mechanism and an electric heating box; the method comprises the steps of system hot nitrogen filling, raw material circulating drying, classified screening and the like. According to the system, the oxygen content in the system can be accurately controlled, the heat energy utilization rate is increased, the krill drying quality is guaranteed, and classified screening of krill drying products is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of marine biological resource processing equipment, and in particular relates to a continuous dynamic closed-loop circulation drying system and method. Background Art

[0002] Antarctic krill is a high value-added marine biological resource, and its drying process is a key link in the production of shrimp powder. In the existing technology, the traditional drying method has the following technical problems that need to be solved: 1. High energy consumption and heat energy waste: The existing drying system mostly adopts segmented steam indirect drying, or is assisted by vacuum, the heat energy utilization rate is less than 40%, and the waste heat in the high-temperature steam condensate water is not effectively recovered, resulting in significant energy waste. Drying equipment cannot complete short-term drying at high temperature (130-150°C), and the heat loss rate is high. 2. Nutrient destruction and oxidation risk: Antarctic krill is rich in heat-sensitive ingredients such as astaxanthin and phospholipid polyunsaturated fatty acids. Traditional drying methods (such as steam discs) are prone to astaxanthin degradation due to material accumulation and repeated moisture absorption of shrimp powder, but local uneven temperature and humidity can easily cause fat oxidation and hydrolysis. Studies have shown that when the moisture content of the material is lower than 20% in the drying stage, the astaxanthin content decreases significantly. 3. Insufficient drying efficiency and process flexibility: Although segmented combined drying (such as independent processing of high, medium and low moisture segments) is suitable for different moisture content stages, the mode switching relies on manual intervention and cannot achieve coordinated regulation of the drying system. 4. It is impossible to achieve graded screening of krill powder. Summary of the invention

[0003] The present invention discloses a continuous dynamic closed-loop drying system and method, aiming to achieve high efficiency, low consumption and nutritional preservation of Antarctic krill powder drying, so as to solve the problems described in the background technology parts 1-4.

[0004] To achieve the above object, the technical solution of the present invention is:

[0005] A continuous dynamic closed-loop circulation drying system comprises: a control system, a circulating ventilation pipeline, and a nitrogen supply mechanism. A drying tower and a drying main unit are connected in series on the circulating ventilation pipeline. The drying main unit is connected to a raw material container through a conveying mechanism and is used to dynamically dry the raw materials entering the drying main unit. The drying tower is provided with a grading and screening mechanism. An air outlet of the drying tower is connected to a heat recovery mechanism through a pipeline. The heat recovery mechanism is connected to an electric heating box. The electric heating box is connected to a nitrogen supply mechanism. The gas output end of the electric heating box is connected to the drying main unit through the circulating ventilation pipeline. The drying main unit is connected to the lower end of the drying tower. A sensor unit is provided in the drying system. The control system is connected to the sensor unit signal and is configured to control the operation of the drying system.

[0006] Preferably, the drying host includes a host housing. A driving shaft is arranged axially inside the host housing, and a number of stirring blades are evenly distributed on the driving shaft. One end of the driving shaft and located outside the host housing is connected with a first driving motor. Driven by the first driving motor, the raw materials entering the host housing are dried during the stirring and turning process.

[0007] Preferably, a first feed inlet is arranged at the top of the host housing. The conveying mechanism is a screw conveyor penetrating the raw material container. The feed end of the screw conveyor is located at the bottom inside the raw material container, and the discharge end is opposite to the first feed inlet. The screw conveyor is driven by a second driving motor. A feed hopper is arranged at the top of the raw material container.

[0008] Preferably, one end of the circulating ventilation pipeline is connected to the side wall of the host housing near the first feed inlet. A first ventilation opening is arranged at the top of the outer wall of the host housing away from the first feed inlet. The first ventilation opening is hermetically connected to the bottom end of the drying tower. A sealing cover is arranged at the top end of the drying tower. The grading and screening mechanism includes a bag filter and a rotating shaft vertically penetrating the sealing cover and rotatably connected to the sealing cover. A number of cutting knives are evenly distributed on the outer wall of the rotating shaft. The top end of the rotating shaft is connected with a third driving motor. A sealing fan for adjusting the air pressure inside the drying tower is connected to the lower part of the outer wall of the drying tower. The sealing fan is connected to the drying tower through a first air outlet pipe and connected to the circulating ventilation pipeline through a first air inlet pipe. The sensor unit includes a first air pressure sensor arranged at a position on the inner wall of the drying tower close to the cutting knives. A second ventilation opening is arranged on the outer wall of the drying tower above the cutting knives. The second ventilation opening is connected to the bottom of the side wall of the bag filter through a first connecting pipe. An air reverse blower is also arranged on one side of the bag filter.

[0009] Preferably, an induced draft fan is arranged on the side of the air reverse blower away from the bag filter. The first air inlet end of the induced draft fan is connected to the second air outlet of the top of the side wall of the bag filter through a second connecting pipe. The first air outlet end of the induced draft fan is connected to the heat energy recovery mechanism through a first pipeline. The second air outlet end of the air reverse blower is connected to the bag filter through a third connecting pipe, and the second air inlet end is connected to the first pipeline through a fourth connecting pipe.

[0010] Preferably, the heat energy recovery mechanism includes a condensing unit and a heat exchanger. The first pipeline is communicated with the inner cavity of the condensing unit. One end of the condensing unit away from the first pipeline is connected to one end of the heat exchanger. The cold water pipeline of the condensing unit is connected in series with the heat exchange pipe of the heat exchanger. One end of the heat exchanger is connected to one end of an electric heating box, and the other end of the electric heating box is connected to the other end of the circulating ventilation pipeline.

[0011] Preferably, the nitrogen supply mechanism is connected to the electric heating box through pipeline II. The sensor unit further includes oxygen concentration sensors disposed on the inner walls of the drying main body and the drying tower. The water inlet and outlet of the condensing unit are respectively connected to the water outlet end and the water inlet end of the water chiller through pipeline III and pipeline IV.

[0012] Preferably, the circulating ventilation pipeline is provided with an exhaust pipe. The first electromagnetic flow regulating valve, the second electromagnetic flow regulating valve, and the third electromagnetic flow regulating valve are respectively provided on the circulating ventilation pipeline, the exhaust pipe, and connecting pipe I. The sensor unit further includes temperature and humidity sensors disposed on the inner walls of the drying main body, the inner walls of the drying tower, and the inner wall of the cavity of the condensing unit. The control system is a PLC controller.

[0013] A working method of a continuous dynamic closed-loop circulation drying system includes: turning on the nitrogen supply mechanism, and the control system enables heated nitrogen to enter the drying system through the induced draft fan. Open the exhaust valve to reduce the oxygen in the drying system to the set standard, and then close the exhaust valve and the nitrogen supply mechanism. The heated nitrogen is circulated in the closed-loop pipeline formed by the circulating ventilation pipeline, the drying main body, the drying tower, connecting pipe I, the bag filter, connecting pipe II, the induced draft fan, pipeline I, the condensing unit, the heat exchanger, and the electric heating box through the induced draft fan to dry the shrimp powder particle raw materials in the drying main body. The moisture in the hot nitrogen is discharged through the condensing unit, and the dried shrimp powder particle raw materials are discharged through the discharge port of the drying main body.

[0014] Preferably, it further includes a classification and screening method, specifically: turn on the sealing fan, and the control system controls the power of the sealing fan based on the signal of the first air pressure sensor. Some of the small-particle-size raw materials in the shrimp powder particle raw materials are driven by the nitrogen flow to the cutter position and chopped into smaller particles. Under the set air pressure data environment, the shrimp powder particles that meet the air pressure dynamic characteristics enter the bag filter through connecting pipe I for recovery, and the remaining shrimp particle particles are recovered through the drying main body. By changing the power of the sealing fan, the classification of shrimp particle particles with different particle sizes is realized.

[0015] The beneficial effects of the continuous dynamic closed-loop circulation drying system and method of the present invention are as follows:

[0016] 1. The closed-loop circulation drying system of the present invention can accurately control the oxygen concentration to <2.0%, effectively avoiding the oxidation of krill lipids and ensuring the product quality.

[0017] 2. The automatic drying of shrimp powder raw materials is realized, improving the drying quality and drying efficiency.

[0018] 3. The thermal energy utilization rate is effectively improved, and the occupied space is saved.

[0019] 4. By regulating the air pressure in the drying tower, the classification and screening of the dried shrimp powder particle raw materials within different particle size ranges can be achieved. Brief Description of the Drawings

[0020] Figure 1 It is a top view layout diagram of a continuous dynamic closed-loop drying system of the present invention;

[0021] Figure 2 It is a front view structural diagram of a continuous dynamic closed-loop drying system of the present invention;

[0022] Figure 3 It is a partial structural diagram (omitting the rotating shaft and the third driving motor) at position A of a continuous dynamic closed-loop drying system of the present invention.

[0023] Reference numerals in the figures: 1, raw material container; 2, screw conveyor; 3, drying main body; 31, main body housing; 32, stirring blade; 4, drying tower; 41, cutter; 42, rotating shaft; 43, third driving motor; 5, connecting pipe; 6, circulating ventilation pipeline; 7, sealing fan; 71, first air outlet pipe; 72, first air inlet pipe; 8, bag filter; 9, reverse blower; 91, fourth connecting pipe; 92, third connecting pipe; 10, induced draft fan; 11, condensing unit; 12, heat exchanger; 13, first driving motor; 14, electric heating box; 15, water chiller; 16, first connecting pipe; 17, second driving motor; 18, sealing cover; 19, feed hopper; 101, second connecting pipe; 102, first pipeline. Detailed Embodiments

[0024] The following description is only for the preferred embodiments of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0025] The following embodiments can be understood as separately expressing a part of the local structure or method of the present invention, or can also be understood as the combination of the embodiments to explain the connotation of the larger scope of the structure or method of the present invention.

[0026] Embodiment 1

[0027] A continuous dynamic closed-loop drying system, as Figures 1-3As shown in the figure, it includes: a control system (not shown in the figure), a circulating ventilation pipeline 6, and a nitrogen supply mechanism (not shown in the figure). A drying tower 4 and a drying main machine 3 are connected in series on the circulating ventilation pipeline 6. The drying main machine 3 is connected to the raw material container 1 through a conveying mechanism and is used to dry the raw materials entering the drying main machine 3 dynamically. The drying tower 4 is provided with a grading and screening mechanism. An air outlet of the drying tower is connected to a heat energy recovery mechanism through a pipeline 102. The heat energy recovery mechanism is connected to an electric heating box 14. The electric heating box 14 is connected to the nitrogen supply mechanism. A gas output end of the electric heating box 14 is connected to the drying main machine 3 through the circulating ventilation pipeline. The drying main machine 3 is connected to the lower end of the drying tower 4. A sensor unit is arranged in the drying system. The control system is in signal connection with the sensor unit and is configured to control the operation of the drying system.

[0028] In this embodiment, the nitrogen supply mechanism is used to fill nitrogen into the system so that the oxygen content in the system reaches below the set standard value, effectively inhibiting the oxidation of krill lipids. Among them, the drying main machine can dynamically stir and dry the shrimp powder particle raw materials. The shrimp powder in the shrimp powder particle raw materials and the shrimp powder obtained by crushing in the drying tower are screened by the grading and screening mechanism. The grading and screening mechanism controls the wind pressure in the drying tower to realize the screening of shrimp powder within a certain particle size range under specific wind pressure conditions, so as to realize the grading of the dried products.

[0029] Embodiment 2

[0030] As Figures 1-3 shown, the drying main machine 3 includes a main machine housing 31. A driving shaft is arranged axially in the main machine housing 31. A plurality of stirring blades 32 are evenly distributed on the driving shaft. One end of the driving shaft and located outside the main machine housing 31 is connected to a first driving motor 13. Driven by the first driving motor 13, the raw materials entering the main machine housing 31 are dried during the stirring and turning process (a discharge port is arranged on the bottom end of the main machine housing near the drying tower side. An electric door is arranged at the discharge port. The stirring blades are arranged in a spiral pattern and push the shrimp particle raw materials towards the discharge port side while stirring. When the detected humidity data reaches the set value, the electric door can be opened for discharging).

[0031] As Figures 1-3 shown, a first feed inlet is arranged at the top of the main machine housing 31. The conveying mechanism is a screw conveyor 2 passing through the raw material container 1. The feed end of the screw conveyor 2 is located at the bottom inside the raw material container 1, and the discharge end is opposite to the first feed inlet. The screw conveyor 2 is driven by a second driving motor 17. A feed hopper 19 is arranged at the top of the raw material container 1.

[0032] Embodiment 3

[0033] As Figures 1-3As shown, one end of the circulating ventilation pipeline 6 is connected to the side wall of the main machine housing 31 near the feeding port. At the top of the outer wall of the main machine housing 31 on the side far from the feeding port, there is a first ventilation port (not marked in the figure). The first ventilation port is hermetically connected to the bottom end of the drying tower 4. The top end of the drying tower 4 is provided with a sealing cover 18. The grading and screening mechanism includes a bag filter 8 and a rotating shaft 42 that vertically penetrates the sealing cover 18 and is rotatably connected to the sealing cover. A number of cutting knives 41 are evenly distributed on the outer wall of the rotating shaft 42. The top end of the rotating shaft 42 is connected to a third driving motor 43. The lower part of the outer wall of the drying tower 4 is connected with a sealing fan 7 for adjusting the air pressure in the drying tower. The sealing fan 7 is connected to the drying tower 4 through an air outlet pipe 71 and is connected to the circulating ventilation pipeline 6 through an air inlet pipe 72. At a position on the inner wall of the drying tower 4 close to the cutting knife 41, there is a first air pressure sensor (not drawn in the figure). Above the cutting knife 41, there is a second ventilation port on the outer wall of the drying tower 4. The second ventilation port is connected to the bottom of the side wall of the bag filter 8 through a connecting pipe 16. On one side of the bag filter 8, there is also an air reverse blower 9.

[0034] As Figure 1 , 2 As shown, on the side of the air reverse blower 9 far from the bag filter 8, there is an induced draft fan 10. The first air inlet end of the induced draft fan 10 is connected to the second air outlet of the top of the side wall of the bag filter 8 through a connecting pipe 101. The first air outlet end of the induced draft fan is connected to the heat energy recovery mechanism through a pipeline 102. The second air outlet end of the air reverse blower 9 is connected to the bag filter 8 through a connecting pipe 92, and the second air inlet end is connected to the pipeline 102 through a connecting pipe 91.

[0035] In this embodiment, the air reverse blower is used to blow back the bag filter to prevent blockage, and at the same time, it promotes the shrimp powder to fall to the bottom of the bag filter and is discharged after accumulating to a certain extent. The induced draft fan is used to provide the air flow circulation power for the whole system. The sealing fan is used to regulate the air pressure in the drying tower to achieve grading and screening. During the grading and screening process, the small particle shrimp powder in the drying tower is in a boiling state. Affected by the set air pressure, a part of the shrimp powder particles enter the bag filter, and the other part of the small particle raw materials fall back to the drying main machine due to their own gravity. Among them, the cutting knife plays a role in cutting the boiling shrimp powder particles into shrimp powder that can enter the bag filter due to the action of air pressure (to improve the grading and screening effect, an axial spiral fan can also be set in the drying tower. Using centrifugal force, the large particle raw materials settle on the periphery, and the shrimp powder that meets the air pressure is discharged upward, that is, the principle of a spiral classifier). The raw materials in the drying tower and the drying main machine are quickly dried by the heated nitrogen.

[0036] Example 4

[0037] As Figure 1 ,2 As shown in the figure, the heat energy recovery mechanism includes a condensing unit 11 and a heat exchanger 12. The first pipeline 102 is communicated with the inner cavity of the condensing unit 11. One end of the condensing unit 11 away from the first pipeline 102 is connected to one end of the heat exchanger 12. The cold water pipeline of the condensing unit 11 is connected in series with the heat exchange pipes of the heat exchanger 12. One end of the heat exchanger 12 is connected to one end of the electric heating box 14, and the other end of the electric heating box 14 is connected to the other end of the circulating ventilation pipeline 6.

[0038] In this embodiment, the nitrogen gas that absorbs moisture passes through the bag filter and enters the condensing unit 11 through the induced draft fan. The moisture in the nitrogen gas is discharged under the condensing action, and then it enters the heat exchanger. At the same time, the cold water pipeline of the condensing unit heats up after absorbing the heat of the nitrogen gas, and the nitrogen gas flowing through the condensing unit cools down. The high-temperature water enters the heat exchange pipes of the heat exchanger and exchanges heat with the flowing nitrogen gas again, so that the temperature of the nitrogen gas rises again, thus effectively improving the utilization rate of heat energy. The heat exchanger of the present invention preferably uses a finned heat exchanger. The nitrogen gas after passing through the heat exchanger re-enters the electric heating box for further heating.

[0039] Embodiment 5

[0040] As Figure 1 、 2 shown in the figure, the nitrogen gas supply mechanism is connected to the electric heating box 14 through the second pipeline. The water inlet and outlet of the condensing unit 11 are respectively connected to the water outlet end and water inlet end of the water chiller 15 through the third pipeline and the fourth pipeline.

[0041] In this embodiment, the nitrogen gas supply mechanism selects a nitrogen generation device, wherein the nitrogen generation purity ≥ 99.9%, and the nitrogen generation capacity ≥ 5 Nm3 / h; in order to effectively monitor the oxygen concentration in the system, oxygen concentration sensors are respectively arranged on the inner wall of the drying host and the inner wall of the drying tower to real-time feedback the oxygen concentration in the system and control the oxygen concentration < 2.0%; in order to achieve the above effects, the control system is based on the monitored data of the oxygen concentration, and realizes the precise control of the oxygen concentration by turning on and off the exhaust pipe and controlling the input amount of nitrogen gas.

[0042] Embodiment 6

[0043] As Figure 1 、 2 shown in the figure, the circulating ventilation pipeline 6 is provided with an exhaust pipe (a common device, not shown in the figure) for discharging the air in the system when filling nitrogen gas. The first electromagnetic flow regulating valve, the second electromagnetic flow regulating valve, and the third electromagnetic flow regulating valve are respectively arranged on the circulating ventilation pipeline 6, the exhaust pipe, and the first connecting pipe 16; the inner walls of the inner wall of the drying host 3, the inner wall of the drying tower 4, and the inner cavity of the condensing unit 11 are respectively provided with temperature and humidity sensors, and the control system is a PLC controller.

[0044] Example 7

[0045] Based on the above embodiments, this embodiment discloses a working method of a continuous dynamic closed-loop circulation drying system. As Figures 1-3 shown, it includes: turning on the nitrogen supply mechanism, and the control system enables the heated nitrogen to enter the drying system through the induced draft fan. Then, open the exhaust valve to reduce the oxygen in the drying system to the set standard, and then close the exhaust valve and the nitrogen supply mechanism; use the induced draft fan to make the heated nitrogen circulate in the closed-loop pipeline formed by the circulating ventilation pipeline, the drying main machine, the drying tower, the first connecting pipe, the bag filter, the second connecting pipe, the induced draft fan, the first pipeline, the condensing unit, the heat exchanger, and the electric heating box to dry the shrimp powder particle raw materials in the drying main machine. The moisture in the hot nitrogen is discharged through the condensing unit, and the dried shrimp powder particle raw materials are discharged through the discharge port of the drying main machine.

[0046] Example 8

[0047] As Figure 1 、 2 shown, it also includes a grading and screening method, specifically: turn on the sealing fan, and the control system controls the power of the sealing fan based on the signal of the first air pressure sensor. Some of the small-particle-size raw materials in the shrimp powder particle raw materials are driven by the nitrogen flow to the cutter position and are chopped into smaller particles. Under the set air pressure data environment, the shrimp powder particles that meet the air pressure dynamic characteristics enter the bag filter through the first connecting pipe for recovery, and the remaining shrimp particle particles are recovered through the drying main machine; by changing the power of the sealing fan, grading of shrimp particle particles with different particle sizes is achieved.

[0048] Example 9

[0049] The drying main machine is an axial flow stirring tank, including a cylindrical main machine housing. Inside the main machine housing, a driving shaft (not marked in the figure) is arranged along the axial direction. Both ends of the driving shaft are rotatably connected to both ends of the main machine housing. One end of the driving shaft penetrates the main machine housing and is connected with a first driving motor. The stirring blades include first stirring blades and second stirring blades. Multiple groups of first stirring blades and second stirring blades are distributed at intervals on the driving shaft. Each group of the first stirring blades and the second stirring blades has multiple blade bodies and is evenly distributed around the driving shaft. The first stirring blades have a certain angle with the plane where the driving shaft axis and the radial direction are located (that is, axial flow blades are formed around the driving shaft), and satisfy that when the first driving motor rotates forward and reverses, the directions of driving the shrimp powder raw materials in the main machine housing to move forward and backward are opposite. The second stirring blades are parallel to the plane where the stirring shaft axis and the radial direction are located at the position where they are located, that is, the second stirring blades drive the shrimp powder raw materials to move circumferentially around the stirring shaft (that is, during the stirring process, not only can the shrimp powder raw materials be moved around the stirring shaft, but also can move forward or backward, so that the raw materials are fully contacted with the hot nitrogen and quickly dried).

Claims

1. A continuous dynamic closed-loop drying system, characterized in that: Including: A control system, a circulating ventilation pipeline, and a nitrogen supply mechanism. A drying tower and a drying main machine are connected in series on the circulating ventilation pipeline. The drying main machine is connected to a raw material container through a conveying mechanism and is used to dry the raw materials entering the drying main machine dynamically. The drying tower is provided with a grading and screening mechanism. An air outlet one of the drying tower is connected to a heat energy recovery mechanism through a pipeline one. The heat energy recovery mechanism is connected to an electric heating box. The electric heating box is connected to the nitrogen supply mechanism. A gas output end of the electric heating box is connected to the drying main machine through the circulating ventilation pipeline. The drying main machine is connected to the lower end of the drying tower. A sensor unit is arranged in the drying system. The control system is in signal connection with the sensor unit and is configured to control the operation of the drying system.

2. The continuous dynamic closed-loop drying system according to claim 1, characterized in that: The drying main machine includes a main machine housing. A driving shaft is arranged axially in the main machine housing. A plurality of stirring blades are evenly distributed on the driving shaft. One end of the driving shaft and located outside the main machine housing is connected with a first driving motor. Driven by the first driving motor, the raw materials entering the main machine housing are dried during the stirring and turning process.

3. The continuous dynamic closed-loop drying system according to claim 2, characterized in that: A feed inlet one is arranged at the top of the main machine housing. The conveying mechanism is a screw conveyor passing through the raw material container. The feed end of the screw conveyor is located at the bottom inside the raw material container, and the discharge end is opposite to the feed inlet one. The screw conveyor is driven by a second driving motor. A feed hopper is arranged at the top of the raw material container.

4. A continuous dynamic closed-loop drying system according to claim 3, characterized in that: One end of the circulating ventilation pipeline is connected to the side wall of the main machine housing close to the feed inlet one. A ventilation opening one is arranged at the top of the outer wall of the main machine housing away from the feed inlet one. The ventilation opening one is hermetically connected to the bottom end of the drying tower. A sealing cover is arranged at the top end of the drying tower. The grading and screening mechanism includes a bag filter and a rotating shaft vertically penetrating the sealing cover and rotatably connected to the sealing cover. A plurality of cutting knives are evenly distributed on the outer wall of the rotating shaft. The top end of the rotating shaft is connected with a third driving motor. A sealing fan for adjusting the air pressure in the drying tower is connected to the lower part of the outer wall of the drying tower. The sealing fan is connected to the drying tower through an air outlet pipe one and is connected to the circulating ventilation pipeline through an air inlet pipe one. The sensor unit includes a first air pressure sensor arranged at a position on the inner wall of the drying tower close to the cutting knife. A ventilation opening two is arranged on the outer wall of the drying tower above the cutting knife. The ventilation opening two is connected to the bottom of the side wall of the bag filter through a connecting pipe one. An air reverse blower is further arranged on one side of the bag filter.

5. The continuous dynamic closed-loop drying system according to claim 4, characterized in that: An induced draft fan is arranged on the side of the air reverse blower away from the bag filter. An air inlet end one of the induced draft fan is connected to an air outlet two at the top of the side wall of the bag filter through a connecting pipe two. An air outlet end one of the induced draft fan is connected to the heat energy recovery mechanism through a pipeline one. An air outlet end two of the air reverse blower is connected to the bag filter through a connecting pipe three, and an air inlet end two is connected to the pipeline one through a connecting pipe four.

6. The continuous dynamic closed-loop drying system according to claim 5, characterized in that: The described heat energy recovery mechanism includes a condensing unit and a heat exchanger. The first pipeline is communicated with the inner cavity of the condensing unit. One end of the condensing unit away from the first pipeline is connected to one end of the heat exchanger. The cold water pipeline of the condensing unit is connected in series with the heat exchange pipes of the heat exchanger. One end of the heat exchanger is connected to one end of the electric heating box, and the other end of the electric heating box is connected to the other end of the circulating ventilation pipeline.

7. The continuous dynamic closed-loop drying system according to claim 6, characterized in that: The described nitrogen supply mechanism is connected to the electric heating box through the second pipeline. The sensor unit further includes oxygen concentration sensors arranged on the inner walls of the drying main machine and the drying tower. The water inlet and outlet of the condensing unit are respectively connected to the water outlet end and the water inlet end of the water chiller through the third pipeline and the fourth pipeline.

8. A continuous dynamic closed-loop drying system according to claim 7, characterized in that: The described circulating ventilation pipeline is provided with an exhaust pipe. The first electromagnetic flow regulating valve, the second electromagnetic flow regulating valve, and the third electromagnetic flow regulating valve are respectively arranged on the circulating ventilation pipeline, the exhaust pipe, and the first connecting pipe. The sensor unit further includes temperature and humidity sensors arranged on the inner walls of the drying main machine, the inner walls of the drying tower, and the inner cavity of the condensing unit. The control system is a PLC controller.

9. The working method of a continuous dynamic closed-loop drying system as claimed in claim 8, characterized by comprising: Open the nitrogen supply mechanism. The control system allows the heated nitrogen to enter the drying system through the induced draft fan. Open the exhaust valve to reduce the oxygen in the drying system to the set standard, and then close the exhaust valve and the nitrogen supply mechanism. Make the heated nitrogen circulate in the closed-loop pipeline formed by the circulating ventilation pipeline, the drying main machine, the drying tower, the first connecting pipe, the bag filter, the second connecting pipe, the induced draft fan, the first pipeline, the condensing unit, the heat exchanger, and the electric heating box to dry the shrimp powder particle raw materials in the drying main machine. The moisture in the hot nitrogen is discharged through the condensing unit, and the dried shrimp powder particle raw materials are discharged through the discharge port of the drying main machine.

10. The working method of a continuous dynamic closed-loop drying system as described in claim 9, characterized in that: It also includes a classification and screening method, specifically: turn on the sealing fan. The control system controls the power of the sealing fan based on the signal of the first air pressure sensor. Some small-particle-size raw materials in the shrimp powder particle raw materials are driven by the nitrogen flow to the cutter position and are chopped into smaller particles. Under the set air pressure data environment, the shrimp powder particles that meet the air pressure dynamic characteristics enter the bag filter through the first connecting pipe for recovery, and the remaining shrimp particle particles are recovered through the drying main machine. By changing the power of the sealing fan, the classification of shrimp particle particles with different particle sizes is realized.

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