Device of a low-temperature spray drying system with upward feed and upward discharge

Abstract

The present invention discloses a device for a low-temperature spray drying system with upward inlet and upward outlet. The present invention breaks through the traditional thinking of completely relying on high temperature to evaporate solvents, and innovatively proposes to remove moisture in the air, so that the incoming air changes from wet air to dry air. During the atomization drying process, the dry air carries the solvent away, thereby reducing the evaporation amount of the solvent and achieving low-temperature drying. The present invention performs spray drying on heat-sensitive materials at low temperature, which can better maintain the activity of the materials, has stable performance, and a high safety factor. It is particularly suitable for temperature-sensitive materials such as microorganisms, various bacterial solutions, enzyme preparations, natural extracts, and Chinese herbal medicines. The present invention adopts a closed-loop circulation system, which saves energy while improving the evaporation efficiency. By adopting an automatic switching combination mode of a low-temperature spray drying system and a dehumidification system, low-temperature spraying is completed more intelligently. The energy-saving system converts waste heat energy into useful heat energy, greatly reducing energy consumption, achieving double energy saving, and saving the production cost of enterprises.

Description

Technical Field

[0001] The present invention belongs to the technical field of spray drying equipment, and specifically relates to a device for a low-temperature spray drying system with upward feeding and upward discharging. Background Art

[0002] Existing spray dryers generally consist of a blower, a heat exchanger, a drying chamber, a cyclone separator, a bag filter, and an induced draft fan. After the blower introduces air, the air is heated by the heat exchanger to keep the air at a relatively high temperature. The moisture in the droplets is evaporated by the high-temperature air to achieve the drying of the material. Generally, the inlet air temperature is above 120°C. For heat-sensitive materials, too high an inlet air temperature is extremely likely to cause the material to lose its activity. Therefore, at present, many heat-sensitive materials are dried by freeze dryers. However, freeze dryers have a long drying time, high energy consumption, and the dried products need to be pulverized twice. The powder is irregular and has poor fluidity. Therefore, it is extremely urgent to develop a device for a low-temperature spray drying system that can well protect the activity of heat-sensitive materials and enable continuous production. Summary of the Invention

[0003] The purpose of the present invention is to provide a device for a low-temperature spray drying system with upward feeding and upward discharging, which breaks through the traditional thinking of completely relying on high temperature to evaporate the solvent, and innovatively proposes to remove the moisture in the air, so that the inlet air changes from wet air to dry air. During the atomization drying process, the dry air carries away the moisture, thereby reducing the evaporation amount of the solvent and achieving low-temperature drying.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] An apparatus of a low-temperature spray drying system with upward feeding and upward discharging, comprising a feeding pump and an atomizing tower. The feeding pump is connected to the atomizing tower through a pipeline. A pressure sensing and transmitting device is fixed on the side wall of the atomizing tower and is connected to the atomizing tower through a pipeline. The atomizing tower is connected to a cyclone separator through a pipeline, and an explosion-proof sheet is provided at one end of the pipeline close to the atomizing tower. A third dew point meter and a second outlet air temperature sensing and transmitting device are successively arranged on the pipeline connecting the atomizing tower and the cyclone separator. The cyclone separator is connected to a bag filter through a pipeline. The bag filter is connected to a first induced draft fan through a pipeline. The first induced draft fan is connected to the input end of a first heat exchanger through a pipeline, and a first air regulating valve is arranged on the pipeline between the first induced draft fan and the first heat exchanger. The first chiller is connected to the heat exchange tubes of the first heat exchanger through a pipeline. The output end of the first heat exchanger is fixedly connected to a first steam-water separator through a pipeline. The first steam-water separator is connected to one end of a second four-way reversing valve through a pipeline. The second four-way reversing valve is respectively connected to the output end of a second heater, the input end of a first AMS workstation, and the input end of a second AMS workstation through pipelines. The input end of the second heater is connected to the output end of a fourth heat exchanger through a pipeline. The input end of the fourth heat exchanger is connected to the output end of a second blower through a pipeline. One end of the heat exchange tubes of the fourth heat exchanger is connected to the output end of a second induced draft fan through a pipeline, and the other end of the heat exchange tubes of the fourth heat exchanger is connected to a second natural air outlet through a pipeline. The input end of the second induced draft fan is connected to one end of the heat exchange tubes of a third heat exchanger through a pipeline, and the other end of the heat exchange tubes of the third heat exchanger is connected to a first natural air inlet through a pipeline. The output ends of the first AMS workstation and the second AMS workstation are both connected to a first four-way reversing valve through pipelines. The other two ends of the first four-way reversing valve are respectively connected to the input end of a filter and the input end of a second air regulating valve through pipelines. The output end of the second air regulating valve is connected to the input end of the third heat exchanger through a pipeline. The output end of the third heat exchanger is connected to the input end of a third steam-water separator through a pipeline. The output end of the third steam-water separator is fixedly connected to the input end of a second heat exchanger through a pipeline. The heat exchange tubes of the second heat exchanger are connected to a second chiller through a pipeline. The output end of the second heat exchanger is connected to the input end of a second steam-water separator through a pipeline. The output end of the second steam-water separator is connected to the input end of the second blower through a pipeline. The output end of the filter is connected to the input end of a first blower through a pipeline. The output end of the first blower is connected to the input end of a first heater through a pipeline. The output end of the first heater is fixedly connected to the atomizing tower through a pipeline. A first inlet air temperature sensing and transmitting device is arranged on the pipeline between the atomizing tower and the first heater. A first dew point meter is arranged on the pipeline between the first four-way reversing valve and the filter. A second dew point meter is arranged on the pipeline between the first four-way reversing valve and the second air regulating valve.A dehumidification temperature sensor transmitter is provided on the pipeline between the second four-way changeover valve and the second heater.

[0006] Further, the four ports of the first four-way changeover valve are respectively an A port, a B port, a C port, and a D port. The A port is connected to a filter, the B port is connected to a first AMS workstation, the C port is connected to a second air damper, and the D port is connected to a second AMS workstation. The A port and the C port are the output ports of the first four-way changeover valve, and the B port and the D port are the input ports of the first four-way changeover valve.

[0007] Further, the four ports of the second four-way changeover valve are respectively an E port, an F port, a G port, and an I port. The E port is connected to a first steam-water separator, the F port is connected to a first AMS workstation, the G port is connected to a second AMS workstation, and the I port is connected to a second heater. The E port and the I port are the input ports of the second four-way changeover valve, and the F port and the G port are the output ports of the second four-way changeover valve.

[0008] Further, the device of the up-in and up-out low-temperature spray drying system includes the following systems: an up-in and up-out structure, a closed-loop circulation system, a condensation system, a low-temperature spray drying system, a four-way valve automatic switching system, a dehumidification system, and an energy-saving system;

[0009] The working mode and principle of the up-in and up-out structure are that natural wind enters from the top of the drying tower, spirals down and then rises to the top of the drying tower and is discharged from the top;

[0010] The working mode and principle of the closed-loop circulation system are to recycle gas.

[0011] Further, the working mode and principle of the condensation system are that the gas discharged through the bag filter has a relatively high temperature. After passing through the heat exchanger, the temperature drops sharply and becomes cold air. Using the dew point difference principle, the originally unsaturated water vapor can become saturated water vapor, and the excess moisture is precipitated. The cold air undergoes steam-water separation in the steam-water separator, and the moisture in the air condenses into droplets and is collected by the steam-water separator. The original air becomes cold air with a low water content and continues to enter the spray drying system.

[0012] Further, the working mode and principle of the low-temperature spray drying system are that after being processed by the condensation system, the gas discharged from the bag filter becomes saturated cold dry gas. The gas is recycled, and before entering the drying tower again, the cold dry gas is heated to make it become unsaturated gas, increasing the water-carrying capacity of the gas. During spray drying, the unsaturated gas will carry the moisture away, reducing the evaporation amount and realizing low-temperature drying.

[0013] Furthermore, the working mode and principle of the four-way valve automatic switching system are as follows:

[0014] 1) Install two four-way valves at the system switching points of the first AMS workstation and the second AMS workstation, and install a dew point meter on each of the two lines. When the first dew point meter detects that the water content in the air is too high, it will feedback to the PLC control system. The control system issues a command, and the four-way valve automatically switches. The second four-way reversing valve connects E and F, and G and I. The first four-way reversing valve connects A and B, and C and D;

[0015] 2) When the second dew point meter detects that the air humidity is too high, the four-way valve switches automatically again. The second four-way reversing valve connects E and G, F and I. The first four-way reversing valve connects A and D, and B and C.

[0016] Furthermore, the working mode and principle of the dehumidification system are as follows: When the first dew point meter detects that the humidity of the first AMS workstation is too high, the dehumidification system will be automatically started. The hot air with a temperature above 250° passes through the FI line of the second four-way reversing valve and reaches the first AMS workstation. The moisture of the first AMS workstation is carried away through high-temperature evaporation and air flow movement, and the first AMS workstation is dried and its water absorption is restored. The high-temperature air flow of 240° passes through the second air regulating valve and reaches the third heat exchanger and the third steam-water separator for cooling. The air flow coming out of the heat exchanger is between 70 - 80°. Then it goes to the second heat exchanger and the second steam-water separator for condensation to reduce the air temperature. The moisture in the air will precipitate, and the water content in the air will become less. The third heat exchanger and the second heat exchanger share the second chiller. The temperature of the gas discharged after condensation is about 40°. It is sent to the fourth heat exchanger through the second air blower and then to the second heater for heating. The heated hot air passes through the first AMS workstation again for dehumidification, forming a closed-loop circulation system.

[0017] Furthermore, the working mode and principle of the energy-saving system are as follows: The high-temperature air flow reaches the third heat exchanger through the second air regulating valve for temperature reduction treatment. There are four air outlets at the third heat exchanger. The left one is the high-temperature hot air inlet with a temperature of 240 °C, and the right one is the high-temperature hot air outlet with a temperature between 70 - 80 °C. Then it undergoes condensation through the second heat exchanger and the second steam-water separator. The temperature of the condensed gas is 40 °C, and it is transmitted to the fourth heat exchanger by the second air blower. There is a natural air inlet left at the lower right of the third heat exchanger with a temperature between 20 - 30 °C, and a hot natural air outlet is provided at the lower left with a temperature of 125 °C. The 125 °C hot natural air is transmitted to the fourth heat exchanger by the second induced draft fan. At the fourth heat exchanger, the 125 °C hot natural air exchanges heat energy with the 40 °C condensed air. After the heat energy exchange, the temperature of the condensed air reaches 80 °C, and then it goes to the second heater for heating. When the temperature reaches the set 250 °C, it enters the first AMS workstation for dehumidification again. The temperature of the hot natural air after the heat energy exchange decreases and is discharged through the second natural air outlet.

[0018] Advantages of the present invention: The low-temperature spray of the present invention can better maintain the activity of materials, providing a new process option for temperature-sensitive materials such as microorganisms, various bacterial solutions, enzyme preparations, natural extracts, and Chinese herbal medicines. With low-temperature spray drying, the drying time is short, which can save time and improve production efficiency. The spray forms powder in one step, with good powder regularity and excellent fluidity, simplifying the process flow and enhancing the company's production capacity. The closed-loop circulation system saves energy while improving evaporation efficiency, has stable performance, and a high safety factor. The automatic switching mode of the low-temperature spray drying system combined with the dehumidification system can complete low-temperature spray more intelligently. The energy-saving system converts waste heat energy into useful heat energy, greatly reducing the energy consumption of machine operation and saving production costs. At the same time, the first air regulating valve and the second air regulating valve are provided to adjust the air volume according to actual needs, maintain the pressure balance in the pipeline, and improve production safety. Brief Description of the Drawings

[0019] For the convenience of those skilled in the art to understand, the present invention will be further described below with reference to the accompanying drawings.

[0020] Figure 1 It is a schematic diagram of the working principle of a device of a low-temperature spray drying system with upward inlet and upward outlet of the present invention. Detailed Embodiments

[0021] Refer to Figure 1As shown in the figure, a device of a low-temperature spray drying system with upward feeding and upward discharging includes a feeding pump 1 and an atomizing tower 3. The feeding pump 1 is connected to the atomizing tower 3 through a pipeline. A pressure sensing and transmitting device 4 is fixed on the side wall of the atomizing tower 3 and is connected to the atomizing tower 3 through a pipeline. The atomizing tower 3 is connected to a cyclone separator 11 through a pipeline, and an explosion-proof film 2 is provided at one end of the pipeline close to the atomizing tower 3. A third dew point meter 9 and a second outlet air temperature sensing and transmitting device 10 are successively provided on the pipeline connecting the atomizing tower 3 and the cyclone separator 11. The cyclone separator 11 is connected to a bag filter 12 through a pipeline, the bag filter 12 is connected to a first induced draft fan 13 through a pipeline, the first induced draft fan 13 is connected to the input end of a first heat exchanger 27 through a pipeline, and a first air regulating valve 14 is provided on the pipeline between the first induced draft fan 13 and the first heat exchanger 27. A first chiller 29 is connected to the heat exchange pipes of the first heat exchanger 27 through a pipeline. The output end of the first heat exchanger 27 is fixedly connected to a first steam-water separator 28 through a pipeline. The first steam-water separator 28 is connected to one end of a second four-way reversing valve 20 through a pipeline. The second four-way reversing valve 20 is connected to the output end of a second heater 22, the input end of a first AMS workstation 18, and the input end of a second AMS workstation 19 through pipelines respectively. The input end of the second heater 22 is connected to the output end of a fourth heat exchanger 23 through a pipeline. The input end of the fourth heat exchanger 23 is connected to the output end of a second air blower 24 through a pipeline. One end of the heat exchange pipes of the fourth heat exchanger 23 is connected to the output end of a second induced draft fan 25 through a pipeline, and the other end of the heat exchange pipes of the fourth heat exchanger 23 is connected to a second natural air outlet 36 through a pipeline. The input end of the second induced draft fan 25 is connected to one end of the heat exchange pipes of a third heat exchanger 30 through a pipeline, and the other end of the heat exchange pipes of the third heat exchanger 30 is connected to a first natural air inlet 35 through a pipeline. The output ends of the first AMS workstation 18 and the second AMS workstation 19 are both connected to a first four-way reversing valve 16 through pipelines. The other two ends of the first four-way reversing valve 16 are respectively connected to the input end of a filter 8 and the input end of a second air regulating valve 26 through pipelines. The output end of the second air regulating valve 26 is connected to the input end of the third heat exchanger 30 through a pipeline. The output end of the third heat exchanger 30 is connected to the input end of a third steam-water separator 34 through a pipeline. The output end of the third steam-water separator 34 is fixedly connected to the input end of a second heat exchanger 31 through a pipeline. The heat exchange pipes of the second heat exchanger 31 are connected to a second chiller 32 through a pipeline. The output end of the second heat exchanger 31 is connected to the input end of a second steam-water separator 33 through a pipeline. The output end of the second steam-water separator 33 is connected to the input end of the second air blower 24 through a pipeline. The output end of the filter 8 is connected to the input end of a first air blower 7 through a pipeline. The output end of the first air blower 7 is connected to the input end of a first heater 6 through a pipeline. The output end of the first heater 6 is fixedly connected to the atomizing tower 3 through a pipeline. A first inlet air temperature sensing and transmitting device 5 is provided on the pipeline between the atomizing tower 3 and the first heater 6.A first dew point meter 15 is provided on the pipeline between the first four-way reversing valve 16 and the filter 8, a second dew point meter 17 is provided on the pipeline between the first four-way reversing valve 16 and the second air regulating valve 26, and a dehumidifying temperature sensing and transmitting device 21 is provided on the pipeline between the second four-way reversing valve 20 and the second heater 22.

[0022] The four ports of the first four-way reversing valve 16 are respectively an A port, a B port, a C port and a D port. The A port is connected to the filter 8, the B port is connected to the first AMS workstation 18, the C port is connected to the second air regulating valve 26, and the D port is connected to the second AMS workstation 19. The A port and the C port are the output ports of the first four-way reversing valve 16, and the B port and the D port are the input ports of the first four-way reversing valve 16.

[0023] The four ports of the second four-way reversing valve 20 are respectively an E port, an F port, a G port and an I port. The E port is connected to the first steam-water separator 28, the F port is connected to the first AMS workstation 18, the G port is connected to the second AMS workstation 19, and the I port is connected to the second heater 22. The E port and the I port are the input ports of the second four-way reversing valve 20, and the F port and the G port are the output ports of the second four-way reversing valve 20.

[0024] The device of the up-in and up-out low-temperature spray drying system includes the following systems: an up-in and up-out structure, a closed-loop circulation system, a condensation system, a low-temperature spray drying system, a four-way valve automatic switching system, a dehumidification system and an energy-saving system.

[0025] The working mode and principle of the up-in and up-out structure are that natural wind enters from the top of the drying tower, spirally descends and then rises to the top of the drying tower and is discharged from the top.

[0026] The working mode and principle of the closed-loop circulation system are to recycle gas.

[0027] The working mode and principle of the condensation system are that the gas discharged through the bag filter 12 has a relatively high temperature. After passing through the heat exchanger, the temperature drops sharply and becomes cold air. When the water vapor content remains unchanged, due to the temperature drop, the originally unsaturated water vapor can become saturated water vapor, and the excess moisture will precipitate. The cold air undergoes steam-water separation in the steam-water separator, and the moisture in the air condenses into droplets and is collected by the steam-water separator. The original air becomes cold air with a low water content and continues to enter the spray drying system.

[0028] The working mode and principle of the low-temperature spray drying system are as follows: After being processed by the condensation system, the gas discharged from the bag filter 12 becomes saturated cold-dried gas, which is recycled. Before entering the drying tower again, the cold-dried gas is heated to make it an unsaturated gas, increasing the water-carrying capacity of the gas. During spray drying, the unsaturated gas will carry away the moisture, reducing the overall evaporation amount and achieving low-temperature drying.

[0029] The working mode and principle of the four-way valve automatic switching system are as follows:

[0030] 1) Install two four-way valves at the system switching point between the first AMS workstation 18 and the second AMS workstation 19, and install a dew point meter on each of the two lines. When the first dew point meter 15 detects that the water content in the air is too high, it will feedback to the PLC control system. The control system issues an order, and the four-way valve automatically switches. The second four-way reversing valve 20 connects E to F and G to I, and the first four-way reversing valve 16 connects A to B and C to D;

[0031] 2) When the second dew point meter 17 detects that the air humidity is too high, the four-way valve automatically switches again. The second four-way reversing valve 20 connects E to G, F to I, and the first four-way reversing valve 16 connects A to D and B to C.

[0032] The working mode and principle of the dehumidification system are as follows: When the first dew point meter 15 detects that the humidity of the first AMS workstation 18 is too high, the dehumidification system will be automatically started. The hot air at a temperature above 250° passes through the FI line of the second four-way reversing valve 20 and reaches the first AMS workstation 18. The moisture of the first AMS workstation 18 is carried away through high-temperature evaporation and air flow movement, and the first AMS workstation is dried and its water absorption capacity is restored. The hot air at 240° passes through the second air regulating valve 26 and reaches the third heat exchanger 30 and the third steam-water separator 34 for cooling. The temperature of the air flow coming out of the heat exchanger is between 70 - 80°. Then it goes to the second heat exchanger 31 and the second steam-water separator 33 for condensation to reduce the air temperature. The moisture in the air will precipitate, and the water content in the air will become less. The third heat exchanger 30 and the second heat exchanger 31 share the second chiller 32. The temperature of the gas discharged after condensation is about 40°. It is transmitted to the fourth heat exchanger 23 by the second blower 24, and then to the second heater 22 for heating. The heated hot air passes through the first AMS workstation 18 again for dehumidification, forming a closed-loop circulation system.

[0033] The working mode and principle of the energy-saving system are as follows: The high-temperature air flow reaches the third heat exchanger 30 through the second air regulating valve 26 for temperature reduction treatment. There are four air inlets at the third heat exchanger 30. The left one is the high-temperature hot air inlet with a temperature of 240 °C, and the right one is the high-temperature hot air outlet with a temperature between 70 - 80 °C. Then it undergoes condensation through the second heat exchanger 31 and the second steam-water separator 33. The temperature of the condensed gas is 40 °C and is transmitted to the fourth heat exchanger 23 by the second air blower 24. There is a natural air inlet at the lower right of the third heat exchanger 30 with a temperature between 20 - 30 °C, and a hot natural air outlet is provided at the lower left with a temperature of 125 °C. The 125 °C hot natural air is transmitted to the fourth heat exchanger 23 by the second induced draft fan 25. At the fourth heat exchanger 23, the 125 °C hot natural air exchanges heat energy with the 40 °C condensed air. After the heat energy exchange, the temperature of the condensed air reaches 80 °C, and then it goes to the second heater 22 for heating. When the temperature reaches the set 250 °C, it enters the first AMS workstation 18 for dehumidification again. The temperature of the hot natural air after the heat energy exchange decreases and is discharged through the second natural air outlet 36.

[0034] Example 1

[0035] The cold and dry air processed by the first AMS workstation 18 passes through the first four-way reversing valve 16, from AB line to the filter 8 for filtration and purification, and is transported to the first heater 6 for heating by the power of the first air blower 7. After heating, the cold and dry air becomes unsaturated hot air and enters the atomization tower 3 for spray drying. The unsaturated hot air in the drying tower can itself carry a part of the moisture, so low-temperature spray drying can be achieved. The air outlet of this system is at the top, and the air flow is discharged from the top of the drying tower and enters the cyclone separator 11 for gas-solid separation. Subsequently, the air flow goes to the bag filter 12 for further dust removal and purification. The purified air is sucked by the first induced draft fan 13 and transported to the first heat exchanger 27 and the first steam-water separator 28 for condensation. By reducing the temperature of the air, the moisture in the air is precipitated, and the hot and humid air becomes cold and dry air. The cold and dry air passes through the EF line of the second four-way reversing valve 20 to the first AMS workstation 18. The first AMS workstation 18 will adsorb the moisture in the cold and dry air again. After this process, the moisture in the cold and dry air is minimal. The cold and dry air is heated again and enters the drying tower, forming a closed-loop system for low-temperature spray drying.

[0036] When the second dew point meter 17 detects that the humidity in the air is too high, it feeds back to the PLC control system. The control system issues a command, and the four-way valve automatically switches. The second four-way reversing valve 20 connects E and F, and G and I. The first four-way reversing valve 16 connects A and B, and C and D. The low-temperature spray drying air flow passes through the first AMS workstation 18, and the above-mentioned closed-loop system for low-temperature spray drying is formed.

[0037] The humidity of the second AMS workstation 19 is too high and dehumidification is required. The operation of the dehumidification system is as follows: High-temperature hot air above 250° reaches the second AMS workstation 19 through the GI line of the second four-way reversing valve 20, and the moisture of the second AMS workstation 19 is carried away through high-temperature evaporation and air flow movement, so that the second AMS workstation 19 is dried and its water absorption is restored. High-temperature air flow of about 240° reaches the third heat exchanger 30 and the third steam-water separator 34 through the second air damper 26 for cooling. The air flow coming out of the heat exchanger is between 70-80°, and then goes to the second heat exchanger 31 and the second steam-water separator 33 for condensation to reduce the temperature of the air. Moisture in the air will precipitate and the water content in the air will become less. The third heat exchanger 30 and the second heat exchanger 31 share a second chiller 32. The temperature of the gas discharged after condensation is about 40°. It is transmitted to the fourth heat exchanger 23 by the second blower 24 for heat energy exchange. There is a natural air inlet at the lower right of the third heat exchanger 30, and the temperature is between 20-30°. There is a hot natural air outlet at the lower left, and the temperature is about 125°. The 125° hot natural air is transmitted to the fourth heat exchanger 23 by the second induced draft fan 25. At the fourth heat exchanger 23, the 125° hot natural air exchanges heat energy with the 40° condensed air. After the heat energy exchange, the condensed air reaches about 80°, and then goes to the second heater 22 for heating. When the temperature reaches the set 250°, it enters the second AMS workstation 19 again for dehumidification, forming an energy-saving and dehumidification closed-loop system.

[0038] Embodiment 2

[0039] When the first dew point meter 15 detects that the humidity in the air is too high, it feeds back to the PLC control system. The control system issues a command, and the four-way valve automatically switches. The second four-way reversing valve 20 connects E to I and E to G. The first four-way valve 16 connects B to C and A to D.

[0040] The low-temperature spray drying air flow passes through the second AMS workstation 19. The cold and dried air processed by the second AMS workstation 19 goes through the AD line of the first four-way reversing valve 16 to the filter 8 for filtration and purification, and is then transported by the power of the first blower 7 to the first heater 6 for heating. After heating, the cold and dried air becomes unsaturated hot air and enters the atomization tower 3 for spray drying. The unsaturated hot air in the drying tower can itself carry a part of the moisture, so low-temperature spray drying can be achieved. The air outlet of this system is at the top. The air flow is discharged from the top of the drying tower and enters the cyclone separator 11 for gas-solid separation. Subsequently, the air flow goes to the bag filter 12 for further dust removal and purification. The purified air is transported by the suction of the first induced draft fan 13 to the first heat exchanger 27 and the first steam-water separator 28 for condensation. By reducing the temperature of the air, the moisture in the air is precipitated, and the hot and humid air becomes cold and dried air. The cold and dried air goes through the EG line of the second four-way reversing valve 20 to the second AMS workstation 19. The second AMS workstation 19 will adsorb the moisture in the cold and dried air again. After this process, the moisture in the cold and dried air is extremely small. The cold and dried air is heated again and enters the drying tower, forming a closed-loop system for low-temperature spray drying.

[0041] The humidity of the first AMS workstation 18 is too high and needs to be dehumidified. The operation of the dehumidification system is as follows: The high-temperature hot air above 250° passes through the FI line of the second four-way reversing valve 20 and reaches the first AMS workstation 18. The moisture of the first AMS workstation 18 is carried away through high-temperature evaporation and air flow movement, and the first AMS workstation is dried and its water absorption capacity is restored. The high-temperature air flow of about 240° passes through the second air regulating valve 26 and reaches the third heat exchanger 30 and the third steam-water separator 34 for temperature reduction. The air flow coming out of the heat exchanger is between 70 - 80°. Then it goes to the second heat exchanger 31 and the second steam-water separator 33 for condensation to reduce the temperature of the air, and the moisture in the air will be precipitated, and the water content in the air will become less. The third heat exchanger 30 and the second heat exchanger 31 share a second chiller 32. The temperature of the gas discharged after condensation is about 40°. It is transported by the second blower 24 to the fourth heat exchanger 23 for heat energy exchange. There is a natural air inlet at the lower right of the third heat exchanger 30, with a temperature between 20 - 30°. There is a hot natural air outlet at the lower left, with a temperature of about 125°. The hot natural air at 125° is transported by the second induced draft fan 25 to the fourth heat exchanger 23. At the fourth heat exchanger 23, the hot natural air at 125° exchanges heat energy with the air at 40° after condensation. After the heat energy exchange, the air after condensation reaches about 80°. Then it goes to the second heater 22 for heating. When the temperature reaches the set 250°, it enters the first AMS workstation 18 again for dehumidification, forming an energy-saving and dehumidification closed-loop system.

[0042] The above Embodiment 1 is the working mode of the low-temperature spray drying system and the system for dehumidifying the second AMS workstation 19, and Embodiment 2 is the working mode of the low-temperature spray drying system and the system for dehumidifying the first AMS workstation 18.

[0043] The above content is only an example and illustration of the structure of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the structure of the invention or exceed the scope defined by this claims, they should all fall within the protection scope of the present invention.

Claims

1. An apparatus for a low-temperature spray drying system with upward feeding and upward discharging, comprising a feeding pump (1) and an atomization tower (3). Characterized in that The feeding pump (1) is connected to the atomizing tower (3) through a pipeline. A pressure sensing transmitter (4) is fixed on the side wall of the atomizing tower (3), and the pressure sensing transmitter (4) is connected to the atomizing tower (3) through a pipeline. The atomizing tower (3) is connected to the cyclone separator (11) through a pipeline, and an explosion-proof sheet (2) is provided at one end of the pipeline close to the atomizing tower (3). A third dew point meter (9) and a second outlet air temperature sensing transmitter (10) are successively provided on the pipeline connecting the atomizing tower (3) and the cyclone separator (11). The cyclone separator (11) is connected to the bag filter (12) through a pipeline, and the bag filter (12) is connected to the first induced draft fan (13) through a pipeline. The first induced draft fan (13) is connected to the input end of the first heat exchanger (27) through a pipeline, and a first air regulating valve (14) is provided on the pipeline between the first induced draft fan (13) and the first heat exchanger (27). The first chiller (29) is connected to the heat exchange tube of the first heat exchanger (27) through a pipeline. The output end of the first heat exchanger (27) is fixedly connected to the first steam-water separator (28) through a pipeline. The first steam-water separator (28) is connected to one end of the second four-way reversing valve (20) through a pipeline. The second four-way reversing valve (20) is connected to the output end of the second heater (22), the input end of the first AMS workstation (18), and the input end of the second AMS workstation (19) through pipelines respectively. The input end of the second heater (22) is connected to the output end of the fourth heat exchanger (23) through a pipeline. The input end of the fourth heat exchanger (23) is connected to the output end of the second air blower (24) through a pipeline. One end of the heat exchange tube of the fourth heat exchanger (23) is connected to the output end of the second induced draft fan (25) through a pipeline, and the other end of the heat exchange tube of the fourth heat exchanger (23) is connected to the second natural air outlet (36) through a pipeline. The input end of the second induced draft fan (25) is connected to one end of the heat exchange tube of the third heat exchanger (30) through a pipeline, and the other end of the heat exchange tube of the third heat exchanger (30) is connected to the first natural air inlet (35) through a pipeline. The output ends of the first AMS workstation (18) and the second AMS workstation (19) are both connected to the first four-way reversing valve (16) through pipelines. The other two ends of the first four-way reversing valve (16) are respectively connected to the input end of the filter (8) and the input end of the second air regulating valve (26) through pipelines. The output end of the second air regulating valve (26) is connected to the input end of the third heat exchanger (30) through a pipeline. The output end of the third heat exchanger (30) is connected to the input end of the third steam-water separator (34) through a pipeline. The output end of the third steam-water separator (34) is fixedly connected to the input end of the second heat exchanger (31) through a pipeline. The heat exchange tube of the second heat exchanger (31) is connected to the second chiller (32) through a pipeline. The output end of the second heat exchanger (31) is connected to the input end of the second steam-water separator (33) through a pipeline,The output end of the second steam separator (33) is connected to the input end of the second air blower (24) through a pipeline. The output end of the filter (8) is connected to the input end of the first air blower (7) through a pipeline. The output end of the first air blower (7) is connected to the input end of the first heater (6) through a pipeline. The output end of the first heater (6) is fixedly connected to the atomizing tower (3) through a pipeline. A first inlet air temperature sensing and transmitting device (5) is provided on the pipeline between the atomizing tower (3) and the first heater (6). A first dew point meter (15) is provided on the pipeline between the first four-way reversing valve (16) and the filter (8). A second dew point meter (17) is provided on the pipeline between the first four-way reversing valve (16) and the second air damper (26). A dehumidification temperature sensing and transmitting device (21) is provided on the pipeline between the second four-way reversing valve (20) and the second heater (22).

2. The apparatus for a low-temperature spray drying system with upward feeding and upward discharging according to claim 1, Characterized in that The apparatus for the low-temperature spray drying system with upward feeding and upward discharging includes the following systems: an upward feeding and upward discharging structure, a closed-loop circulation system, a condensation system, a low-temperature spray drying system, a four-way valve automatic switching system, a dehumidification system, and an energy-saving system; The working mode and principle of the upward feeding and upward discharging structure are that natural wind enters from the top of the drying tower, spirally descends and then rises to the top of the drying tower and is discharged from the top; The working mode and principle of the closed-loop circulation system are to recycle gas.

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