The wet granulation production process uses a high-speed rotary wet granulator and a vibrating fluidized bed drying unit to synthesize granulation linkage lines, which has been widely used in many domestic pharmaceutical companies. According to the principle of domestic equipment selection: energy saving and environmental protection. We must put a series of requirements on the equipment when selecting equipment, including technical feasibility discussions with suppliers. Here, we discuss several topics with reference to the UTC terms of the fluidized bed required by the US FDA.
1 The basic principle of energy-saving fluidized bed drying of fluidized bed drying equipment is to blow the wet particles to a boiling convection state by heated air, and the hot air takes away the evaporated water or organic solvent to achieve drying of the wet particles. It is related to the handling of air.
At present, many domestic manufacturers have configured the air treatment unit as: primary filter-electric heating (or steam heating)-fan-medium efficiency filter-vibrating fluidized bed dryer, which is as simple as this. Obviously, this has a great relationship with the user's needs. The user's request is low, and the manufacturer's configuration is also low. Here we only use the fluidized bed in the GEA granulation linkage line as an example to talk about the configuration and The relationship of energy saving. Air handling unit configuration and parameter requirements:
(1) The inlet air temperature and humidity can be adjusted to the parameter range required by the process, t is 80 ° C, RH is 20%;
(2) The chilled water is cooled and dehumidified, the coil is made of copper tube and aluminum rib type, and the chilled water is chilled water of the process chilled water system, the temperature is 7-12 ° C;
(3) The heat source of the heater is industrial steam, and the requirements for pressure and temperature consumption should be indicated;
(4) The filter adopts (G4+F8+H13) three-stage filtration, and H13 needs to perform PAO leak detection test and verification, indicating the time of detection and replacement;
(5) Vibrating fluidized bed drying machine body requirements: the inner wall is made of stainless steel plate with high efficiency, and the galvanized steel plate is high-efficiency before, and the wall plate has heat preservation and anti-cooling function;
(6) The entry and exit of cold water and steam is automatically controlled according to the set temperature and humidity by PLC electric valve or pneumatic valve;
(7) G4, F8, H13 have differential pressure display device, and have differential pressure alarm function in PLC (pressure difference is not displayed on PLC);
(8) The filter is easy to replace and disassemble;
(9) Configure the surface cooler drain trap, the material of the water tray is 304 stainless steel, no water leakage, smooth drainage, no water in the water collecting tray;
(10) The air outlet is equipped with an electric regulating valve, and the opening degree can be controlled by PLC.
This is our requirement for the configuration of the air handling unit (AHU). It is believed that many domestic manufacturers can fully meet these requirements. If the domestic equipment is manufactured according to this requirement, the quality risk of the pharmaceutical production must be reduced, and the detailed verification is supplemented. The document will further increase the technical content of the equipment.
Spray drying has been applied in many fields due to its short process, handling of heat sensitive materials, and ease of enlargement. After the reform and opening up, a large number of specialized drying equipment enterprises have emerged in China. In the past ten years, the spray dryer technology has made great progress, and the product quality is comparable to that of the world famous manufacturers. It not only meets the needs of domestic light chemical industry and environmental protection industry, but also has expanded to foreign markets.
For a long time, attention to spray drying devices has generally focused on:
(1) selection of atomizer (machine);
(2) adequate air volume and heat configuration;
(3) Powder recovery and discharge.
Wang Xizhong pointed out: "The design of a successful spray dryer should include the hot air inlet and outlet mode and the hot air distribution device that are compatible with the atomizer" [1]. K. Master's also mentions that the rate of water evaporation in the drying tower increases as the relative velocity of the droplets and hot air increases.
Tang Jinxin et al. proposed three important principles in the design requirements of hot air distributors, all of which emphasized the importance of hot air distribution for spray drying. In the devices that appeared later, it was found that most enterprises still did not pay enough attention, but they were structurally “like†and the essence was still not grasped, resulting in the following situations:
(1) The temperature difference in the same section of the tower is large, resulting in local sticking of the material;
(2) Due to the unreasonable contact between the gas and liquid phases, the drying strength is greatly reduced, and the volume of the drying tower is increased.
(3) In a drying tower which is much smaller than the original design, the flow rate range of the hot air distribution is not paid attention to, the drying strength is lowered, and the material still has a large amount of sticking;
(4) The thermal efficiency is very low, and the wind temperature of the tower is difficult to drop.
Therefore, we believe that the design of the hot air distributor is correct or not, which directly affects the success or failure of the drying system.
1 The basic principle of energy-saving fluidized bed drying of fluidized bed drying equipment is to blow the wet particles to a boiling convection state by heated air, and the hot air takes away the evaporated water or organic solvent to achieve drying of the wet particles. It is related to the handling of air.
At present, many domestic manufacturers have configured the air treatment unit as: primary filter-electric heating (or steam heating)-fan-medium efficiency filter-vibrating fluidized bed dryer, which is as simple as this. Obviously, this has a great relationship with the user's needs. The user's request is low, and the manufacturer's configuration is also low. Here we only use the fluidized bed in the GEA granulation linkage line as an example to talk about the configuration and The relationship of energy saving. Air handling unit configuration and parameter requirements:
(1) The inlet air temperature and humidity can be adjusted to the parameter range required by the process, t is 80 ° C, RH is 20%;
(2) The chilled water is cooled and dehumidified, the coil is made of copper tube and aluminum rib type, and the chilled water is chilled water of the process chilled water system, the temperature is 7-12 ° C;
(3) The heat source of the heater is industrial steam, and the requirements for pressure and temperature consumption should be indicated;
(4) The filter adopts (G4+F8+H13) three-stage filtration, and H13 needs to perform PAO leak detection test and verification, indicating the time of detection and replacement;
(5) Vibrating fluidized bed drying machine body requirements: the inner wall is made of stainless steel plate with high efficiency, and the galvanized steel plate is high-efficiency before, and the wall plate has heat preservation and anti-cooling function;
(6) The entry and exit of cold water and steam is automatically controlled according to the set temperature and humidity by PLC electric valve or pneumatic valve;
(7) G4, F8, H13 have differential pressure display device, and have differential pressure alarm function in PLC (pressure difference is not displayed on PLC);
(8) The filter is easy to replace and disassemble;
(9) Configure the surface cooler drain trap, the material of the water tray is 304 stainless steel, no water leakage, smooth drainage, no water in the water collecting tray;
(10) The air outlet is equipped with an electric regulating valve, and the opening degree can be controlled by PLC.
This is our requirement for the configuration of the air handling unit (AHU). It is believed that many domestic manufacturers can fully meet these requirements. If the domestic equipment is manufactured according to this requirement, the quality risk of the pharmaceutical production must be reduced, and the detailed verification is supplemented. The document will further increase the technical content of the equipment.
Spray drying has been applied in many fields due to its short process, handling of heat sensitive materials, and ease of enlargement. After the reform and opening up, a large number of specialized drying equipment enterprises have emerged in China. In the past ten years, the spray dryer technology has made great progress, and the product quality is comparable to that of the world famous manufacturers. It not only meets the needs of domestic light chemical industry and environmental protection industry, but also has expanded to foreign markets.
For a long time, attention to spray drying devices has generally focused on:
(1) selection of atomizer (machine);
(2) adequate air volume and heat configuration;
(3) Powder recovery and discharge.
Wang Xizhong pointed out: "The design of a successful spray dryer should include the hot air inlet and outlet mode and the hot air distribution device that are compatible with the atomizer" [1]. K. Master's also mentions that the rate of water evaporation in the drying tower increases as the relative velocity of the droplets and hot air increases.
Tang Jinxin et al. proposed three important principles in the design requirements of hot air distributors, all of which emphasized the importance of hot air distribution for spray drying. In the devices that appeared later, it was found that most enterprises still did not pay enough attention, but they were structurally “like†and the essence was still not grasped, resulting in the following situations:
(1) The temperature difference in the same section of the tower is large, resulting in local sticking of the material;
(2) Due to the unreasonable contact between the gas and liquid phases, the drying strength is greatly reduced, and the volume of the drying tower is increased.
(3) In a drying tower which is much smaller than the original design, the flow rate range of the hot air distribution is not paid attention to, the drying strength is lowered, and the material still has a large amount of sticking;
(4) The thermal efficiency is very low, and the wind temperature of the tower is difficult to drop.
Therefore, we believe that the design of the hot air distributor is correct or not, which directly affects the success or failure of the drying system.
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