A large-scale spray drying system with nitrogen closed circulation for organic solvents

Abstract

The present invention relates to a large-scale spray drying system for organic solvent nitrogen closed circulation, which belongs to the field of spray drying. The spray drying system comprises a slurry conveying device, a slurry drying device, a product bin, a nitrogen dehumidification device and a gas mixing tank. The slurry drying device uses nitrogen to dry the slurry and separates the solid particles of the material from the slurry. The nitrogen dehumidification device separates nitrogen and organic solvent, and the separated nitrogen is recycled in the slurry drying device and the gas mixing tank. The present invention adopts nitrogen closed circulation and is suitable for drying materials of organic solvents.

Description

Technical Field

[0001] The invention relates to the field of spray drying, in particular to a large-scale spray drying system for organic solvent nitrogen closed circulation. Background Art

[0002] With the large-scale development of organic solvent spray drying systems, closed explosion-proof spray dryers are used to spray dry solutions and recover dry powder or particles and organic solvents. The airtightness of the system, the recovery rate of dry powder or particles and organic solvents, and the reuse rate of circulating nitrogen are directly related to the safety of production and the competitiveness of products. Therefore, it is of great practical significance to develop a large-scale organic solvent nitrogen closed circulation spray drying system. Summary of the invention

[0003] The purpose of the present invention is to provide a large-scale spray drying system with organic solvent nitrogen closed circulation, which utilizes the closed circulation of nitrogen to achieve the drying of slurry materials containing organic solvents.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A large-scale organic solvent nitrogen closed circulation spray drying system, the spray drying system comprising: a slurry conveying device, a slurry drying device, a product bin, a nitrogen dehumidification device and a gas mixing tank;

[0006] The slurry outlet of the slurry conveying device is connected to the slurry inlet of the slurry drying device, and the slurry conveying device is used to heat and pressurize the slurry and convey the heated and pressurized slurry to the slurry drying device; the slurry includes materials and organic solvents;

[0007] The first gas inlet of the slurry drying device is connected to the gas outlet of the nitrogen dehumidifier, the second gas inlet of the slurry drying device is connected to the gas outlet of the gas mixing tank, the product outlet of the slurry drying device is connected to the product bin, and the gas outlet of the slurry drying device is connected to the gas inlet of the nitrogen dehumidifier; the slurry drying device is used to atomize the heated and pressurized slurry, and then use the nitrogen delivered by the nitrogen dehumidifier as the heating gas to dry the atomized slurry to generate solid particles of the material, and deliver the solid particles of the material to the product bin, and deliver the nitrogen delivered by the gas mixing tank and the atomized organic solvent in the slurry to the nitrogen dehumidifier together with the nitrogen;

[0008] The gas outlet of the nitrogen dehumidification device is also connected to the gas inlet of the gas mixing tank; the nitrogen dehumidification device is used to dehumidify the nitrogen, separate the nitrogen and the organic solvent, transport the separated nitrogen to the slurry drying device and the gas mixing tank respectively, and discharge the organic solvent.

[0009] Optionally, the slurry conveying device includes: a feed kettle and a metering pump;

[0010] The slurry outlet of the feed kettle is connected to the slurry inlet of the metering pump, and the slurry outlet of the metering pump is connected to the slurry inlet of the slurry drying device; the feed kettle is used to heat the slurry and transport the heated slurry to the metering pump; the metering pump is used to pressurize the heated slurry and transport the pressurized slurry to the slurry drying device.

[0011] Optionally, the slurry drying device includes: a carrier gas heater, a spray drying tower, a cyclone bag dust collector and a screw conveyor;

[0012] The gas inlet of the carrier gas heater is connected to the gas outlet of the nitrogen dehumidifier, and the gas outlet of the carrier gas heater is connected to the gas inlet of the spray drying tower; the carrier gas heater is used to heat the nitrogen delivered by the nitrogen dehumidifier and then deliver it to the spray drying tower;

[0013] The slurry inlet of the spray drying tower is connected to the slurry outlet of the metering pump, the first outlet of the spray drying tower is connected to the product bin, and the second outlet of the spray drying tower is connected to the first inlet of the cyclone bag dust collector; the spray drying tower is used to atomize the pressurized slurry, and then use the heated nitrogen as the heating gas to dry the atomized slurry to generate solid particles of the material, and transport a part of the solid particles of the material to the product bin, and the other part of the solid particles of the material and the atomized organic solvent in the slurry are transported to the cyclone bag dust collector together with the dried nitrogen;

[0014] The second inlet of the cyclone bag dust collector is connected to the gas outlet of the gas mixing tank, the material outlet of the cyclone bag dust collector is connected to the product bin through a screw conveyor, and the gas outlet of the cyclone bag dust collector is connected to the gas inlet of the nitrogen dehumidification device; the cyclone bag dust collector is used to separate solid particles of the material, and transport the separated solid particles of the material to the product bin through a screw conveyor, and the separated nitrogen and the atomized organic solvent are transported to the nitrogen dehumidification device.

[0015] Optionally, the nitrogen dehumidification device includes: a venturi mixer, a spray tower and a cooling tower;

[0016] The gas inlet of the venturi mixer is connected to the gas outlet of the cyclone bag filter, the solution inlet of the venturi mixer is connected to the first solution outlet of the spray tower, and the outlet of the venturi mixer is connected to the first inlet of the spray tower; the venturi mixer is used to mix the separated nitrogen and the atomized organic solvent and the organic solution transported by the spray tower, and transport the gas-liquid mixture to the spray tower;

[0017] The second inlet of the spray tower is connected to the outlet of the cooling tower, the second solution outlet of the spray tower is connected to the inlet of the cooling tower, and the gas outlet of the spray tower is connected to the gas inlet of the carrier gas heater; the spray tower is used to dehumidify nitrogen by circulating an organic solvent; the cooling tower is used to cool the organic solvent, a part of the cooled organic solvent is discharged, and another part of the cooled organic solvent is refluxed to the spray tower.

[0018] Optionally, the nitrogen dehumidification device further comprises: a circulation fan, a venturi circulation pump, a spray tower circulation pump and a blower;

[0019] The gas inlet of the circulation fan is connected to the gas outlet of the cyclone bag filter, and the gas outlet of the circulation fan is connected to the gas inlet of the venturi mixer; the circulation fan is used to suck the separated nitrogen into the venturi mixer;

[0020] The venturi circulation pump is arranged between the solution inlet of the venturi mixer and the first solution outlet of the spray tower, and the venturi circulation pump is used to transport the gas-liquid mixture to the spray tower;

[0021] The spray tower circulation pump is arranged between the second solution outlet of the spray tower and the inlet of the cooling tower, and the spray tower circulation pump is used to transport the organic solvent output by the spray tower to the cooling tower;

[0022] The blower is arranged between the spray tower and the carrier gas heater, and is used for conveying the nitrogen exhausted from the spray tower to the carrier gas heater.

[0023] Optionally, the spray drying system further comprises: a product bin bag;

[0024] The product bin cloth bag is arranged on the top of the product bin;

[0025] The gas inlet of the product bin bag is connected to the gas outlet of the gas mixing tank, and the gas outlet of the product bin bag is connected to the gas inlet of the circulating fan; the product bin bag is used to use the nitrogen delivered by the gas mixing tank as the purge gas for the solid particles of the material in the product bin, and mix the output nitrogen with the nitrogen separated by the cyclone bag dust collector and the atomized organic solvent and then deliver it to the circulating fan.

[0026] Optionally, the spray drying system further comprises: a gas condenser, a gas buffer tank and a compressor;

[0027] The gas inlet of the gas condenser is connected to the gas outlet of the blower, the gas outlet of the gas condenser is connected to the gas inlet of the gas buffer tank, and the liquid outlet of the gas condenser is connected to the third inlet of the spray tower; the gas condenser is used to cool a part of the nitrogen after the blower is pressurized, and the cooled liquid organic solvent flows back to the spray tower, and the uncooled nitrogen enters the gas buffer tank;

[0028] The gas inlet of the compressor is connected to the gas outlet of the gas buffer tank, and the gas outlet of the compressor is connected to the gas inlet of the gas mixing tank; the compressor is used to extract and compress the nitrogen in the gas buffer tank, a part of the compressed nitrogen is discharged, and the other part of the nitrogen is sent to the gas mixing tank and mixed with the low-pressure nitrogen.

[0029] Optionally, the feed kettle comprises an agitator and a gas phase condenser, and the feed kettle is heated by one of steam, hot water or thermal oil.

[0030] Optionally, the carrier gas heater is a fin heating type, an electric heating type, a thermal oil heating type, or a combination of any two of the above.

[0031] Optionally, the spray tower is a cyclone plate tower, a packed tower or a plate tower.

[0032] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0033] The invention discloses a large-scale spray drying system for organic solvent nitrogen closed circulation, the spray drying system comprises a slurry conveying device, a slurry drying device, a product bin, a nitrogen dehumidification device and a gas mixing tank, the slurry drying device uses nitrogen to dry the slurry, separates the solid particles of the material from the slurry, the nitrogen dehumidification device separates nitrogen and the organic solvent, and the separated nitrogen is circulated and reused in the slurry drying device and the gas mixing tank. The invention adopts nitrogen closed circulation and is suitable for drying materials of organic solvents. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0035] Figure 1 This is a schematic structural diagram of a large-scale organic solvent nitrogen closed circulation spray drying system provided by the present invention.

[0036] Explanation of symbols: 1-feed kettle; 2-metering pump; 3-carrier gas heater; 4-spray drying tower; 5-cyclone bag dust collector; 6-spray drying tower discharge valve; 7-cyclone bag discharge valve; 8-screw conveyor; 9-product bin; 10-product bin discharge valve; 11-circulating fan; 12-Venturi mixer; 13-spray tower; 14-Venturi circulation pump; 15-spray tower circulation pump; 16-cooler; 17-blower; 18-gas condenser; 19-gas buffer tank; 20-compressor; 21-gas mixing tank. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The purpose of the present invention is to provide a large-scale spray drying system with organic solvent nitrogen closed circulation, which utilizes the closed circulation of nitrogen to achieve the drying of slurry materials containing organic solvents.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] The present invention provides a large-scale spray drying system for organic solvent nitrogen closed circulation, such as Figure 1 As shown, the spray drying system includes: a slurry conveying device, a slurry drying device, a product bin 9, a nitrogen dehumidification device and a gas mixing tank 21.

[0041] The slurry outlet of the slurry conveying device is connected to the slurry inlet of the slurry drying device. The slurry conveying device is used to heat and pressurize the slurry, and convey the heated and pressurized slurry to the slurry drying device. The slurry includes materials and organic solvents. The first gas inlet of the slurry drying device is connected to the gas outlet of the nitrogen dehumidifier, the second gas inlet of the slurry drying device is connected to the gas outlet of the gas mixing tank 21, the product outlet of the slurry drying device is connected to the product bin 9, and the gas outlet of the slurry drying device is connected to the gas inlet of the nitrogen dehumidifier; the slurry drying device is used to atomize the heated and pressurized slurry, and then use the nitrogen conveyed by the nitrogen dehumidifier as the heating gas to dry the atomized slurry to generate solid particles of the material, and convey the solid particles of the material to the product bin 9, and convey the nitrogen conveyed by the gas mixing tank 21 and the atomized organic solvent in the slurry to the nitrogen dehumidifier together with the nitrogen. The gas outlet of the nitrogen dehumidifier is also connected to the gas inlet of the gas mixing tank 21; the nitrogen dehumidifier is used to dehumidify the nitrogen, separate the nitrogen and the organic solvent, and transport the separated nitrogen to the slurry drying device and the gas mixing tank 21 respectively, and discharge the organic solvent.

[0042] Reference Figure 1 In one example, the slurry conveying device includes: a feed kettle 1 and a metering pump 2. The slurry outlet of the feed kettle 1 is connected to the slurry inlet of the metering pump 2, and the slurry outlet of the metering pump 2 is connected to the slurry inlet of the slurry drying device; the feed kettle 1 is used to heat the slurry and convey the heated slurry to the metering pump 2; the metering pump 2 is used to pressurize the heated slurry and convey the pressurized slurry to the slurry drying device. The feed kettle 1 heats the upstream material to 70°C to reduce the viscosity of the raw materials for easy transportation. The material at the bottom of the feed kettle 1 is pressurized to 3-5MPa by the metering pump 2 and enters the 6-12 groups of nozzles of the spray drying tower 4 for atomization.

[0043] The slurry drying device includes: a carrier gas heater 3, a spray drying tower 4, a cyclone bag dust collector 5 and a screw conveyor 8. The gas inlet of the carrier gas heater 3 is connected to the gas outlet of the nitrogen dehumidification device, and the gas outlet of the carrier gas heater 3 is connected to the gas inlet of the spray drying tower 4; the carrier gas heater 3 is used to heat the nitrogen transported by the nitrogen dehumidification device and then transport it to the spray drying tower 4. The slurry inlet of the spray drying tower 4 is connected to the slurry outlet of the metering pump 2, the first outlet of the spray drying tower 4 is connected to the product bin 9, and the second outlet of the spray drying tower 4 is connected to the first inlet of the cyclone bag dust collector 5; the spray drying tower 4 is used to atomize the pressurized slurry, and use the heated nitrogen as the heating gas to dry the atomized slurry to generate material solid particles, and transport a part of the material solid particles to the product bin 9, and the other part of the material solid particles and the atomized organic solvent in the slurry are transported to the cyclone bag dust collector 5 together with the dried nitrogen. The second inlet of the cyclone bag dust collector 5 is connected to the gas outlet of the gas mixing tank 21, the material outlet of the cyclone bag dust collector 5 is connected to the product bin 9 through the screw conveyor 8, and the gas outlet of the cyclone bag dust collector 5 is connected to the gas inlet of the nitrogen dehumidification device; the cyclone bag dust collector 5 is used to separate the solid particles of the material, and transport the separated solid particles of the material to the product bin 9 through the screw conveyor 8, and the separated nitrogen and the atomized organic solvent are transported to the nitrogen dehumidification device.

[0044] The circulating nitrogen is heated to 150-180°C by medium-pressure steam through the carrier gas heater 3, and enters the spray drying tower 4 to dry the atomized particles with 6-12 groups of nozzles in the downstream, and the temperature after drying is 95-110°C. Most of the dried solid particles fall directly into the product bin 9 through the spray drying tower discharge valve 6, and a small part of the dried solid particles are discharged from the bottom of the spray drying tower 4 to the cyclone bag dust collector 5 along with the circulating nitrogen. The solid particles separated by the cyclone bag dust collector 5 are transported to the product bin 9 through the cyclone bag discharge valve 7 and the screw conveyor 8 in turn. The materials in the product bin 9 are regularly discharged through the product bin discharge valve 10.

[0045] The nitrogen dehumidification device includes: a venturi mixer 12, a spray tower 13 and a cooling tower. The gas inlet of the venturi mixer 12 is connected to the gas outlet of the cyclone bag filter 5, the solution inlet of the venturi mixer 12 is connected to the first solution outlet of the spray tower 13, and the outlet of the venturi mixer 12 is connected to the first inlet of the spray tower 13; the venturi mixer 12 is used to mix the separated nitrogen and the atomized organic solvent and the organic solution transported by the spray tower 13, and transport the gas-liquid mixed liquid to the spray tower 13. The second inlet of the spray tower 13 is connected to the outlet of the cooling tower, the second solution outlet of the spray tower 13 is connected to the inlet of the cooling tower, and the gas outlet of the spray tower 13 is connected to the gas inlet of the carrier gas heater 3; the spray tower 13 is used to dehumidify the nitrogen by circulating the organic solvent; the cooling tower is used to cool the organic solvent, a part of the cooled organic solvent is discharged, and another part of the cooled organic solvent is refluxed to the spray tower 13.

[0046] The nitrogen dehumidification device also includes: a circulating fan 11, a venturi circulating pump 14, a spray tower circulating pump 15 and a blower 17. The gas inlet of the circulating fan 11 is connected to the gas outlet of the cyclone bag filter 5, and the gas outlet of the circulating fan 11 is connected to the gas inlet of the venturi mixer 12; the circulating fan 11 is used to suck the separated nitrogen to the venturi mixer 12. The venturi circulating pump 14 is arranged between the solution inlet of the venturi mixer 12 and the first solution outlet of the spray tower 13, and the venturi circulating pump 14 is used to transport the gas-liquid mixed liquid to the spray tower 13. The spray tower circulating pump 15 is arranged between the second solution outlet of the spray tower 13 and the inlet of the cooling tower, and the spray tower circulating pump 15 is used to transport the organic solvent output by the spray tower 13 to the cooling tower. The blower 17 is arranged between the spray tower 13 and the carrier gas heater 3, and the blower 17 is used to transport the nitrogen discharged from the spray tower 13 to the carrier gas heater 3.

[0047] The spray drying system also includes: product bin bag. The product bin bag is arranged on the top of the product bin 9. The gas inlet of the product bin bag is connected to the gas outlet of the gas mixing tank 21, and the gas outlet of the product bin bag is connected to the gas inlet of the circulating fan 11; the product bin bag is used to use the nitrogen delivered by the gas mixing tank 21 as the purge gas for the solid particles of the material in the product bin 9, and mix the output nitrogen with the nitrogen separated by the cyclone bag dust collector 5 and the atomized organic solvent and then deliver it to the circulating fan 11.

[0048] The product bin 9 has a built-in bag filter, which is back-flushed with circulating nitrogen and separated from the gas phase by the cyclone bag filter 5, and then sucked by the circulating fan 11 and sent to the venturi mixer 12 and the spray tower 13 for washing and dehumidification. The venturi circulating pump 14 extracts the circulating solvent from the bottom of the spray tower 13 and sends it to the venturi mixer 12 to be continuously mixed with the circulating nitrogen. The spray tower circulating pump 15 also extracts the circulating solvent from the bottom of the spray tower 13 and exchanges heat to -10℃ through the cooler 16 to circulate and spray the circulating nitrogen in the spray tower 13. The circulating nitrogen coming out of the spray tower 13 is pressurized by the blower 17, and a part of it returns to the carrier gas heater 3 for recycling.

[0049] The spray drying system also includes: a gas condenser 18, a gas buffer tank 19 and a compressor 20. The gas inlet of the gas condenser 18 is connected to the gas outlet of the blower 17, the gas outlet of the gas condenser 18 is connected to the gas inlet of the gas buffer tank 19, and the liquid outlet of the gas condenser 18 is connected to the third inlet of the spray tower 13; the gas condenser 18 is used to cool a part of the nitrogen pressurized by the blower 17, the cooled liquid organic solvent flows back to the spray tower 13, and the uncooled nitrogen enters the gas buffer tank 19. The gas inlet of the compressor 20 is connected to the gas outlet of the gas buffer tank 19, and the gas outlet of the compressor 20 is connected to the gas inlet of the gas mixing tank 21; the compressor 20 is used to extract and compress the nitrogen in the gas buffer tank 19, a part of the compressed nitrogen is discharged, and the other part of the nitrogen is sent to the gas mixing tank 21 and mixed with the low-pressure nitrogen. The circulating nitrogen from the spray tower 13 is pressurized by the blower 17, and the other part is cooled to -10°C by the gas condenser 18. The liquid phase flows back to the spray tower 13, and the gas phase enters the gas buffer tank 19. The compressor 20 extracts a small amount of gas phase components in the gas buffer tank 19 and discharges them externally, and most of them are sent to the gas mixing tank 21 to mix with the external low-pressure nitrogen, and finally sent to the cyclone bag dust collector 5 and the bag set on the top of the product bin 9 to act as a purge gas to maintain the nitrogen balance in the system.

[0050] Exemplarily, the feed kettle 1 includes an agitator and a gas phase condenser, and the feed kettle 1 is heated by steam, hot water or thermal oil. The type of the carrier gas heater 3 is a fin heating type, an electric heating type, a thermal oil heating type, or a combination of any two. The combined heating type is steam + electricity, steam + thermal oil or thermal oil + electricity. The spray tower 13 is a cyclone plate tower, a packed tower or a plate tower. The spray drying tower 4 is a pressure type or a centrifugal spray drying tower.

[0051] In order to control the oxygen content, fresh nitrogen is used to seal the rotating equipment. The spray drying system of the present invention can be operated continuously and is particularly suitable for drying and recovering organic solvents.

[0052] The embodiment of the present invention adopts a large-scale spray drying system with nitrogen closed circulation for organic solvents. Since the nitrogen closed circulation is adopted, it is suitable for drying materials with organic solvents. The system has the characteristics of high solid product recovery rate, high nitrogen circulation utilization rate, small amount of circulating cooling water, energy saving and environmental protection. Obviously, the present invention can be widely promoted and applied to the drying of materials with toxic gases or materials that are prone to oxidation during the drying process, and has broad application prospects.

[0053] The embodiments of the present invention have the following advantages:

[0054] 1. The system has a closed nitrogen cycle and nitrogen recycling, which is safe.

[0055] 2. The cyclone bag dust collector + Venturi mixer + spray tower combined dust removal and dehumidification method is adopted, which has a high solid product recovery rate, good washing and dehumidification effect, reduces the amount of circulating cooling water, and is energy-saving and environmentally friendly.

[0056] 3. In large-scale spray drying systems, the exhaust nitrogen is condensed with circulating refrigerant to recover organic solvents. The condensed exhaust nitrogen is returned to the bag for recycling through a compressor. The organic solvent recovery efficiency is high and the nitrogen circulation efficiency is improved.

[0057] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0058] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A large-scale organic solvent nitrogen closed cycle spray drying system, characterized in that: The spray drying system comprises: a slurry conveying device, a slurry drying device, a product bin, a nitrogen dehumidification device and a gas mixing tank; The slurry outlet of the slurry conveying device is connected to the slurry inlet of the slurry drying device, and the slurry conveying device is used to heat and pressurize the slurry and convey the heated and pressurized slurry to the slurry drying device; the slurry includes materials and organic solvents; The first gas inlet of the slurry drying device is connected to the gas outlet of the nitrogen dehumidifier, the second gas inlet of the slurry drying device is connected to the gas outlet of the gas mixing tank, the product outlet of the slurry drying device is connected to the product bin, and the gas outlet of the slurry drying device is connected to the gas inlet of the nitrogen dehumidifier; the slurry drying device is used to atomize the heated and pressurized slurry, and then use the nitrogen delivered by the nitrogen dehumidifier as the heating gas to dry the atomized slurry to generate solid particles of the material, and deliver the solid particles of the material to the product bin, and deliver the nitrogen delivered by the gas mixing tank and the atomized organic solvent in the slurry to the nitrogen dehumidifier together with the nitrogen; The gas outlet of the nitrogen dehumidification device is also connected to the gas inlet of the gas mixing tank; the nitrogen dehumidification device is used to dehumidify the nitrogen, separate the nitrogen and the organic solvent, transport the separated nitrogen to the slurry drying device and the gas mixing tank respectively, and discharge the organic solvent; The spray drying system also includes: a gas condenser, a gas buffer tank and a compressor; The nitrogen dehumidification device comprises: a venturi mixer, a spray tower, a cooling tower and a blower; the gas inlet of the gas condenser is connected to the gas outlet of the blower in the nitrogen dehumidification device, the gas outlet of the gas condenser is connected to the gas inlet of the gas buffer tank, and the liquid outlet of the gas condenser is connected to the third inlet of the spray tower in the nitrogen dehumidification device; the gas condenser is used to cool a part of the nitrogen pressurized by the blower, the cooled liquid organic solvent is refluxed to the spray tower, and the uncooled nitrogen enters the gas buffer tank; The gas inlet of the compressor is connected to the gas outlet of the gas buffer tank, and the gas outlet of the compressor is connected to the gas inlet of the gas mixing tank; the compressor is used to extract and compress the nitrogen in the gas buffer tank, a part of the compressed nitrogen is discharged, and the other part of the nitrogen is sent to the gas mixing tank and mixed with the low-pressure nitrogen.

2. The organic solvent nitrogen closed cycle large-scale spray drying system according to claim 1 is characterized in that: The slurry conveying device comprises: a feed kettle and a metering pump; The slurry outlet of the feed kettle is connected to the slurry inlet of the metering pump, and the slurry outlet of the metering pump is connected to the slurry inlet of the slurry drying device; the feed kettle is used to heat the slurry and transport the heated slurry to the metering pump; the metering pump is used to pressurize the heated slurry and transport the pressurized slurry to the slurry drying device.

3. The organic solvent nitrogen closed cycle large-scale spray drying system according to claim 2 is characterized in that: The slurry drying device comprises: a carrier gas heater, a spray drying tower, a cyclone bag dust collector and a screw conveyor; The gas inlet of the carrier gas heater is connected to the gas outlet of the nitrogen dehumidifier, and the gas outlet of the carrier gas heater is connected to the gas inlet of the spray drying tower; the carrier gas heater is used to heat the nitrogen delivered by the nitrogen dehumidifier and then deliver it to the spray drying tower; The slurry inlet of the spray drying tower is connected to the slurry outlet of the metering pump, the first outlet of the spray drying tower is connected to the product bin, and the second outlet of the spray drying tower is connected to the first inlet of the cyclone bag dust collector; the spray drying tower is used to atomize the pressurized slurry, and then use the heated nitrogen as the heating gas to dry the atomized slurry to generate solid particles of the material, and transport a part of the solid particles of the material to the product bin, and the other part of the solid particles of the material and the atomized organic solvent in the slurry are transported to the cyclone bag dust collector together with the dried nitrogen; The second inlet of the cyclone bag dust collector is connected to the gas outlet of the gas mixing tank, the material outlet of the cyclone bag dust collector is connected to the product bin through a screw conveyor, and the gas outlet of the cyclone bag dust collector is connected to the gas inlet of the nitrogen dehumidification device; the cyclone bag dust collector is used to separate solid particles of the material, and transport the separated solid particles of the material to the product bin through a screw conveyor, and the separated nitrogen and the atomized organic solvent are transported to the nitrogen dehumidification device.

4. The organic solvent nitrogen closed cycle large-scale spray drying system according to claim 3 is characterized in that: The gas inlet of the venturi mixer is connected to the gas outlet of the cyclone bag filter, the solution inlet of the venturi mixer is connected to the first solution outlet of the spray tower, and the outlet of the venturi mixer is connected to the first inlet of the spray tower; the venturi mixer is used to mix the separated nitrogen and the atomized organic solvent and the organic solution transported by the spray tower, and transport the gas-liquid mixture to the spray tower; The second inlet of the spray tower is connected to the outlet of the cooling tower, the second solution outlet of the spray tower is connected to the inlet of the cooling tower, and the gas outlet of the spray tower is connected to the gas inlet of the carrier gas heater; the spray tower is used to dehumidify nitrogen by circulating an organic solvent; the cooling tower is used to cool the organic solvent, a part of the cooled organic solvent is discharged, and another part of the cooled organic solvent is refluxed to the spray tower.

5. The organic solvent nitrogen closed cycle large-scale spray drying system according to claim 4 is characterized in that: The nitrogen dehumidification device also includes: a circulation fan, a venturi circulation pump and a spray tower circulation pump; The gas inlet of the circulation fan is connected to the gas outlet of the cyclone bag filter, and the gas outlet of the circulation fan is connected to the gas inlet of the venturi mixer; the circulation fan is used to suck the separated nitrogen into the venturi mixer; The venturi circulation pump is arranged between the solution inlet of the venturi mixer and the first solution outlet of the spray tower, and the venturi circulation pump is used to transport the gas-liquid mixture to the spray tower; The spray tower circulation pump is arranged between the second solution outlet of the spray tower and the inlet of the cooling tower, and the spray tower circulation pump is used to transport the organic solvent output by the spray tower to the cooling tower; The blower is arranged between the spray tower and the carrier gas heater, and is used for conveying the nitrogen exhausted from the spray tower to the carrier gas heater.

6. The organic solvent nitrogen closed cycle large-scale spray drying system according to claim 5, characterized in that: The spray drying system further comprises: a product bin bag; The product bin cloth bag is arranged on the top of the product bin; The gas inlet of the product bin bag is connected to the gas outlet of the gas mixing tank, and the gas outlet of the product bin bag is connected to the gas inlet of the circulating fan; the product bin bag is used to use the nitrogen delivered by the gas mixing tank as the purge gas for the solid particles of the material in the product bin, and mix the output nitrogen with the nitrogen separated by the cyclone bag dust collector and the atomized organic solvent and then deliver it to the circulating fan.

7. The organic solvent nitrogen closed cycle large-scale spray drying system according to claim 2, characterized in that: The feed kettle comprises a stirrer and a gas phase condenser, and the feed kettle is heated by steam, hot water or thermal oil.

8. The organic solvent nitrogen closed cycle large-scale spray drying system according to claim 3, characterized in that: The carrier gas heater is a fin heating type, an electric heating type, a thermal oil heating type, or a combination of any two of the above.

9. The organic solvent nitrogen closed cycle large-scale spray drying system according to claim 1, characterized in that: The spray tower is a cyclone plate tower, a packed tower or a plate tower.

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