Spray Dryer
FAQ Summary of Spray Dryer
Time：2018.03.16
1. Serious sticky wall phenomenon
The main performance is that there are sticky wet powders everywhere in the drying room. The reason is that the feed amount is too large to fully evaporate; the drying chamber is insufficiently heated prior to the start of spraying; when the spraying is started, the discharge flow rate is adjusted to be too large; the fed liquid is unstable. In response to the different causes of the above problems, the following measures can be taken in sequence: appropriately reducing the amount of feed; appropriately increasing the inlet and outlet temperatures of hot air. When starting spraying, the flow rate should be small and gradually increase until it is adjusted; Check whether it is blocked, adjust the solid content of the material to ensure the fluidity of the liquid.
2. Too high product moisture content
Exhaust air temperature is the main factor affecting the moisture content of the finished product, so the reason for the high moisture content of the product is generally the too low exhaust air temperature. The exhaust air temperature can be adjusted by the amount of feed. Therefore, the corresponding measure is to appropriately reduce the amount of feed to increase the exhaust temperature.
3. Low purity and excessive impurity of product
Possible reasons for this situation are the following: (1) Poor air filtration; (2) Incorporation of accumulated powder into the finished product; (3) Low purity of raw materials; (4) Incomplete cleaning of equipment. The remedial measures that can be taken are: check whether the filter material in the air filter is laid evenly and whether the filter is used for too long; if any, then it should be replaced immediately; check the situation of the coke powder at the entrance of the hot air to overcome the eddy current; before spraying, the material should be filtered ; re-clean the equipment.
The product powder is too fine, the powder running phenomenon is serious, and the product yield is low.
Too fine product particles will affect their solubility and reconstitution performance. The reason is that the solid content is too low or the feed amount is too small. The remedial measure is to increase the solid content of the feed liquid, increase the feed volume, and increase the air inlet temperature. The excessive loss of running powder greatly affects the yield of the finished product. The general reason is that the separation effect of the cyclone separator is poor. If this happens, check whether the cyclone separator is deformed due to knocking or collision; increase the airtightness of the cyclone separator inlet and outlet, check whether there is blockage in the inner wall and the discharge outlet. Of course, the separation efficiency is also related to the specific gravity of the powder and the size of the particles. Some materials may be added to the second-stage dust removal as needed.
The centrifugal nozzle speed is too low and the evaporation is too low.
The main problem is that the components of the centrifugal spray head have failed. Therefore, stop using the spray head and check the internal components of the spray head. The reasons may be: the air volume of the entire system is reduced; the inlet temperature of the hot air is low; the device has the phenomenon of air leakage and cold air enters the drying room. The remedial measures are: check whether the centrifuge speed is normal; check whether the position of the centrifuge control valve is correct; check whether the air filter and air heater pipe is blocked; check whether the grid voltage is normal; check the electric heater is working properly; check the equipment whether the component connection in equipment is sealed.
4. Existence of noise or vibration when the centrifugal nozzle operates
Mainly due to improper cleaning and maintenance of the nozzle, cause the residual material in the spray plate or the main shaft to produce bending and deformation, it may be that the dynamic balance of centrifugal disk is not good. Solution: Check whether there are any remaining substances in the spray disk. If any, please clean it in time. If there is abnormality in the spindle, replace it and re-adjust or replace the balance of the disk.
The main performance is that there are sticky wet powders everywhere in the drying room. The reason is that the feed amount is too large to fully evaporate; the drying chamber is insufficiently heated prior to the start of spraying; when the spraying is started, the discharge flow rate is adjusted to be too large; the fed liquid is unstable. In response to the different causes of the above problems, the following measures can be taken in sequence: appropriately reducing the amount of feed; appropriately increasing the inlet and outlet temperatures of hot air. When starting spraying, the flow rate should be small and gradually increase until it is adjusted; Check whether it is blocked, adjust the solid content of the material to ensure the fluidity of the liquid.
2. Too high product moisture content
Exhaust air temperature is the main factor affecting the moisture content of the finished product, so the reason for the high moisture content of the product is generally the too low exhaust air temperature. The exhaust air temperature can be adjusted by the amount of feed. Therefore, the corresponding measure is to appropriately reduce the amount of feed to increase the exhaust temperature.
3. Low purity and excessive impurity of product
Possible reasons for this situation are the following: (1) Poor air filtration; (2) Incorporation of accumulated powder into the finished product; (3) Low purity of raw materials; (4) Incomplete cleaning of equipment. The remedial measures that can be taken are: check whether the filter material in the air filter is laid evenly and whether the filter is used for too long; if any, then it should be replaced immediately; check the situation of the coke powder at the entrance of the hot air to overcome the eddy current; before spraying, the material should be filtered ; re-clean the equipment.
The product powder is too fine, the powder running phenomenon is serious, and the product yield is low.
Too fine product particles will affect their solubility and reconstitution performance. The reason is that the solid content is too low or the feed amount is too small. The remedial measure is to increase the solid content of the feed liquid, increase the feed volume, and increase the air inlet temperature. The excessive loss of running powder greatly affects the yield of the finished product. The general reason is that the separation effect of the cyclone separator is poor. If this happens, check whether the cyclone separator is deformed due to knocking or collision; increase the airtightness of the cyclone separator inlet and outlet, check whether there is blockage in the inner wall and the discharge outlet. Of course, the separation efficiency is also related to the specific gravity of the powder and the size of the particles. Some materials may be added to the second-stage dust removal as needed.
The centrifugal nozzle speed is too low and the evaporation is too low.
The main problem is that the components of the centrifugal spray head have failed. Therefore, stop using the spray head and check the internal components of the spray head. The reasons may be: the air volume of the entire system is reduced; the inlet temperature of the hot air is low; the device has the phenomenon of air leakage and cold air enters the drying room. The remedial measures are: check whether the centrifuge speed is normal; check whether the position of the centrifuge control valve is correct; check whether the air filter and air heater pipe is blocked; check whether the grid voltage is normal; check the electric heater is working properly; check the equipment whether the component connection in equipment is sealed.
4. Existence of noise or vibration when the centrifugal nozzle operates
Mainly due to improper cleaning and maintenance of the nozzle, cause the residual material in the spray plate or the main shaft to produce bending and deformation, it may be that the dynamic balance of centrifugal disk is not good. Solution: Check whether there are any remaining substances in the spray disk. If any, please clean it in time. If there is abnormality in the spindle, replace it and re-adjust or replace the balance of the disk.