Closed cycle fluidized drying system

Abstract

The utility model discloses a closed cycle fluidized drying system which comprises a drying main machine and a gas circulation loop, the top of the drying main machine is communicated with an air inlet of the gas circulation loop through an exhaust pipeline, the closed cycle fluidized drying system further comprises a back flushing pipeline, and the back flushing pipeline comprises a back flushing fan, a back flushing air bag and a back flushing pipe. An air inlet of the back-blowing fan is communicated with the air circulation loop, an air inlet of the back-blowing air bag is communicated with an air outlet of the back-blowing fan, an air outlet of the back-blowing air bag is communicated with the back-blowing pipe, and the back-blowing pipe is arranged above a dust removal filter bag arranged in the drying main machine. According to the utility model, a large amount of nitrogen can be saved, tail gas treatment links are reduced, the production efficiency is improved, the organic solvent can be better recovered, the production cost is reduced, the pollution of the organic solvent to the environment is avoided, and the safety of the operation process is ensured.

Description

Technical Field

[0001] This utility model belongs to the field of drying technology, and specifically relates to a closed-loop circulating boiling drying system. Background Technology

[0002] In recent years, closed-loop circulating fluidized bed dryers have been widely used in the pharmaceutical, chemical, and food industries. This equipment uses nitrogen as the drying medium, effectively solving the problem of recovering and reusing organic solvents from materials, while simultaneously meeting environmental protection requirements for exhaust emissions and safety standards for personnel operation.

[0003] Currently, traditional closed-loop fluidized bed drying technology uses external backflushing nitrogen gas introduced into the backflushing air manifold to remove material from the surface of the filter bags, ensuring normal system operation. However, this process causes a gradual increase in the slight positive pressure within the system, disrupting the pressure balance. When the system pressure exceeds the set value, pressure must be released through the pressure relief port to maintain balance, resulting in significant nitrogen consumption. This excessive nitrogen usage not only increases the economic burden on enterprises but also removes heat and organic solvents during pressure relief, increasing energy consumption, potentially causing air pollution, and reducing organic solvent recovery. Therefore, reducing energy consumption, minimizing nitrogen consumption, and improving efficiency during production is a major challenge for enterprises. Optimizing production processes and reducing nitrogen usage are crucial for improving production efficiency and economic benefits. Utility Model Content

[0004] To address the aforementioned issues, this invention discloses a closed-loop circulating boiling drying system, which not only saves a significant amount of nitrogen and reduces tail gas treatment steps, thereby improving production efficiency, but also better recovers organic solvents, reduces production costs, avoids environmental pollution from organic solvents, and ensures the safety of the operation process.

[0005] The specific technical solution of this utility model is as follows:

[0006] A closed-loop circulating fluidized bed drying system includes a drying host and a gas circulation loop. The top of the drying host is connected to the air inlet of the gas circulation loop via an exhaust pipe. The system also includes a backflush pipeline, which includes a backflush blower, a backflush air manifold, and a backflush pipe. The air inlet of the backflush blower is connected to the gas circulation loop, the air inlet of the backflush air manifold is connected to the air outlet of the backflush blower, and the air outlet of the backflush air manifold is connected to the backflush pipe. The backflush pipe is positioned above a dust filter bag built into the drying host.

[0007] Preferably, the gas circulation loop includes a dust collector, a closed-loop fan, a surface coolant recovery unit, a main heater, and a filter assembly connected in sequence. The air inlet of the dust collector is connected to the exhaust end of the drying host through an exhaust pipe, and the air outlet of the filter assembly is connected to the air inlet of the drying host to form a gas circulation. The pipe between the main heater and the filter assembly is connected to the air inlet of the backflush pipe.

[0008] Preferably, the air inlet of the backflush pipe is connected to the air outlet of the backflush air manifold via a backflush butterfly valve. A plurality of backflush nozzles are arranged on the backflush pipe, and the backflush nozzles are positioned above the dust collector filter bag and correspond one-to-one with the dust collector filter bag.

[0009] Preferably, the top of the drying host is provided with a pressure relief port.

[0010] Preferably, the filter assembly is a single-stage high-efficiency filter or a combination of multiple high-efficiency filters.

[0011] Beneficial effects: This utility model discloses a closed-loop circulating boiling drying system. By adding a backflush duct between the main heater and the filter assembly, nitrogen gas inside the system is used for backflush to clean the dust filter bag. This not only maintains a slightly positive pressure state inside the system and reduces the use of nitrogen gas, but also avoids pressure relief operations, thereby effectively preventing heat loss and material leakage inside the system. This is beneficial to meeting environmental protection requirements, improving the recovery rate of organic solvents, and significantly improving production efficiency. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the system flow of Example 1;

[0013] Figure 2 This is a schematic diagram of the installation of the backflush pipe and dust filter bag in Example 1;

[0014] In the diagram: 1. Drying unit; 2. Dust filter bag; 3. Backflush pipe; 3-1. Backflush butterfly valve; 3-2. Backflush nozzle; 4. Backflush air manifold; 5. Pressure relief port; 6. Dust collector; 7. Closed-loop fan; 8. Surface coolant recovery unit; 9. Main heater; 10. Filter assembly; 11. Backflush blower. Detailed Implementation

[0015] The present invention will now be described with reference to the accompanying drawings. Several improvements and modifications will be made to the present invention. These improvements and modifications should also be considered within the scope of protection of the present invention. Example 1

[0016] like Figure 1-2As shown, a closed-loop circulating boiling drying system includes a drying host 1 and a gas circulation loop. The top of the drying host 1 is connected to the air inlet of the gas circulation loop through an exhaust pipe. It also includes a backflush pipeline, which includes a backflush blower 11, a backflush air manifold 4, and a backflush pipe 3. The air inlet of the backflush blower 11 is connected to the gas circulation loop, the air inlet of the backflush air manifold 4 is connected to the air outlet of the backflush blower 11, and the air outlet of the backflush air manifold 4 is connected to the backflush pipe 3. The backflush pipe 3 is located above the dust removal filter bag 2 built into the drying host 1.

[0017] In this embodiment 1, the gas circulation loop includes a dust collector 6, a closed circulation fan 7, a surface coolant recovery unit 8, a main heater 9, and a filter assembly 10 connected in sequence. The air inlet of the dust collector 6 is connected to the exhaust end of the dryer 1 through an exhaust pipe, and the air outlet of the filter assembly 10 is connected to the air inlet of the dryer 1 to form a gas circulation. The pipe between the main heater 9 and the filter assembly 10 is connected to the air inlet of the backflush pipe.

[0018] In this embodiment 1, the air inlet of the backflush pipe 3 is connected to the air outlet of the backflush air manifold 4 through the backflush butterfly valve 3-1. Several backflush nozzles 3-2 are arranged on the backflush pipe 3. The backflush nozzles 3-2 are arranged above the dust removal filter bag 2 and correspond one-to-one with the dust removal filter bag 2.

[0019] To further ensure the safety and stability of the system's operating pressure, a pressure relief port 5 is installed on the top of the dryer unit 1. When the pressure inside the dryer unit 1 exceeds a set threshold, the pressure relief port will quickly open to release the excess gas, thereby ensuring that the pressure inside the system remains within a safe range. This stable pressure environment helps maintain the normal operation of the drying system and improves the reliability and stability of the equipment.

[0020] In this embodiment 1, the filter assembly 10 can be a single-stage high-efficiency filter or a multi-stage filter combination.

[0021] Taking nitrogen as an example, the working principle of this invention is as follows:

[0022] Nitrogen gas circulates within the system under the action of a closed-loop fan 7, maintaining a slight positive pressure. The material boils within the drying unit 1 under the influence of hot nitrogen air. Organic solvents in the material 11 are carried out by the flowing hot nitrogen air and, after passing through the dust collector 6, circulate to the surface coolant recovery unit 8 for condensation and recovery. The condensed nitrogen gas is then heated and filtered by the main heater 9 and filter assembly 10 before re-entering the drying unit 1, thus completing the drying process. Simultaneously, a backflush pipeline added between the main heater 9 and filter assembly 10 utilizes the nitrogen within the system for backflush operation. Specifically, the backflush fan 12 delivers heated nitrogen to the backflush air manifold 4, and the backflush butterfly valve 3-1 is opened according to a preset backflush operating procedure to initiate the backflush operation. When the backflush butterfly valve 3-1 is opened, the high-pressure nitrogen gas stored in the backflush air tank 4 enters the backflush pipe 3, and then through the backflush nozzle 3-2, backflushs the dust material adhering to the surface of the dust collector filter bag 2, ensuring normal boiling and drying of the material. Since the backflush nitrogen gas comes from inside the system, the slight positive pressure inside the system will not change, the pressure relief port 5 will not automatically open to relieve pressure due to the increase in system pressure, the heat inside the system will not be lost, and organic solvents or other toxic and harmful substances in the material will not leak out.

[0023] In this invention, the procedure for controlling the backflushing operation can be adjusted according to the actual backflushing effect, which is a conventional technology. It does not require an additional flow switch valve; the backflushing air volume can be controlled simply by adjusting the frequency of the backflushing blower 11.

[0024] The above description is merely an illustration of the present utility model and represents a preferred embodiment of the present utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the scope of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A closed-loop circulating boiling drying system, comprising a drying host and a gas circulation loop, wherein the top of the drying host is connected to the air inlet of the gas circulation loop via an exhaust pipe, characterized in that, It also includes a backflush pipeline, which includes a backflush blower, a backflush air manifold, and a backflush pipe. The air inlet of the backflush blower is connected to the gas circulation loop, the air inlet of the backflush air manifold is connected to the air outlet of the backflush blower, and the air outlet of the backflush air manifold is connected to the backflush pipe. The backflush pipe is positioned above the dust removal filter bag built into the drying host.

2. The closed-loop circulating fluidized bed drying system according to claim 1, characterized in that, The gas circulation loop includes a dust collector, a closed-loop fan, a surface coolant recovery unit, a main heater, and a filter assembly connected in sequence. The air inlet of the dust collector is connected to the exhaust end of the dryer through an exhaust pipe, and the air outlet of the filter assembly is connected to the air inlet of the dryer to form a gas circulation. The pipe between the main heater and the filter assembly is connected to the air inlet of the backflush pipe.

3. The closed-loop circulating fluidized bed drying system according to claim 1, characterized in that, The air inlet of the backflush pipe is connected to the air outlet of the backflush air manifold via a backflush butterfly valve. Several backflush nozzles are arranged on the backflush pipe, and the backflush nozzles are positioned above the dust collector filter bag and correspond one-to-one with the dust collector filter bag.

4. The closed-loop circulating fluidized bed drying system according to claim 1, characterized in that, The top of the drying unit is equipped with a pressure relief port.

5. The closed-loop circulating fluidized bed drying system according to claim 2, characterized in that, The filter assembly is a single-stage high-efficiency filter or a combination of multiple high-efficiency filters.

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