Centrifugal spray dryer use, maintenance, troubleshooting

The following checks should be made before using the centrifugal spray dryer:

1. Check the joints of the bearing and sealing parts of the various devices of the dryer for looseness;

2. Check the lubricating oil condition of each mechanical component and whether the water, wind and slurry valve ports are in the required position;

3. Check if the sealing material is installed at the pipe joint, and then connect it to ensure that unheated air is not allowed to enter the drying chamber;

4. Check whether the door and the observation window are closed and leaking;

5. Check if the rotation direction of the centrifugal fan is correct;

6. Check if the adjustment butterfly valve at the exit of the centrifugal fan is open. Do not close the butterfly valve, otherwise the electric heater and the air inlet pipe will be damaged. This must be fully paid attention to;

7. Check if the connecting pipe of the feed pump is connected properly, and whether the direction of rotation of the motor and the pump is correct;

8. Check whether the top of the drying chamber is placed at the top of the spray head to avoid air leakage.

9. Whether the atomizer lubrication oil cooling pipe joint is connected and whether the cooling water is turned on.

Then, turn on the power to check whether the voltage and the meter are normal. Finally, check the amount and concentration of the slurry in the slurry mixing tank. If there is any problem, it should be eliminated in time.

Daily operation

1. First turn on the centrifugal fan, then turn on the electric heating, and check if there is any air leakage. If it is normal, the barrel body can be preheated. The hot air preheating determines the evaporation capacity of the drying equipment, without affecting the quality of the dried material. Under the premise, the inlet air temperature should be increased as much as possible;

2. When preheating, the bottom of the drying chamber and the valve at the lower part of the cyclone separator must be closed to prevent cold air from entering the drying chamber and reduce the preheating efficiency;

3. When the inlet temperature of the drying chamber reaches the target temperature of 180 °C~220 °C, turn on the centrifugal nozzle. When the nozzle reaches the maximum speed, turn on the feed pump and add the feed liquid. The feed amount should be small to large, otherwise the sticky wall will be generated. Phenomenon until adjusted to the appropriate amount. The concentration of the liquid should be prepared according to the temperature of the dry nature of the material to ensure good fluidity of the finished product after drying;

4, the temperature and humidity of the dried product, depending on the exhaust air temperature, in the operation process, it is extremely important to ensure that the exhaust air temperature is a constant, depending on the amount of feed, the feed amount is stable, and the outlet temperature is Not changed. The outlet temperature may also change if the solid content and flow rate of the feed liquid changes;

5, the product temperature is too low, can reduce the amount of feed to increase the outlet temperature. The temperature of the product is too high, and vice versa. For heat sensitive materials with lower product temperature, the amount of material can be increased to reduce the exhaust air temperature, but the humidity of the product will increase accordingly;

6. The dried product is collected. It should be exchanged in the lower part of the tower body and the pollinator in the lower part of the cyclone before the pollinator is filled. When the pollinator is replaced, the butterfly valve must be closed before proceeding. ;

7. If the dried product has hygroscopicity, the cyclone separator and its pipeline, and the part of the pollinator is wrapped with insulating material, so as to avoid moisture absorption and moisture absorption of the dried product.

In addition, for materials with low heat sensitivity and low softening point, when the exhaust air temperature is too high, the material softens and the cooling air volume needs to be increased.

End and cleaning

After the centrifugal spray dryer is in normal operation, it should also check the operation of each system regularly and record the process parameters. At the end, the heating device should be shut down first, and the liquid should be replaced by water to rinse the residual material of the tube, and then the pump is turned off. When the inlet temperature is reduced below 100 °C, the operation of the blower and the blower can be stopped. Then clean the remaining materials in the drying tower and the precipitator, turn off the dust collector and the air hammer, and finally turn off the main power supply to complete the production operation. In case of emergency, the equipment must be shut down immediately. The blower and feed pump should be shut down first. If there is a sudden power outage, the tower body should be naturally cooled, then the drain valve should be opened, the slurry in the slurry pipeline should be drained, and the equipment should be cleaned.

In addition, after use, the spray disc should be removed, immersed in water, and the residual material washed with water. Brush it with a brush when it is not washed with water. Because the residual material on the spray plate will bring about the unbalance of the spray, which will seriously affect the service life of the spray head and even damage other parts. Do not lay down after the nozzle is finished and during transportation. Improper placement will cause the spindle to bend and affect the use, so it should be placed in a fixed frame.

Cleaning

In order to ensure the cleaning of the drying tower body and its pipes and all the parts in contact with the finished product, it is necessary to obtain first-class products and regular cleaning equipment. When the product variety is changed, or if the equipment has been discontinued for more than 24 hours without being cleaned, a thorough and thorough cleaning should be carried out.

The cleaning method can be selected according to the actual choice of dry cleaning, wet washing or chemical washing.

Dry cleaning: Clean with a brush or vacuum cleaner (for small dryers).

Wet wash: Wash with hot water at 60~80 °C.

Chemical washing: Wash with lye, acid and various detergents. Among them, pickling: HNO3 is formulated into a 1~2% concentration solution, the heating temperature is not more than 65 °C for washing, and then washed with water; alkali washing: NaOH is formulated into a 0.5~1% concentration solution, the heating temperature does not exceed 65 Wash at °C and then rinse with water.

After wet and chemical washing, the equipment and components should be installed and autoclaved for 15~30min.

When cleaning equipment, be careful not to wash with chlorine and its compounds.

The cleaning of the air filter should be based on the surrounding environmental conditions, that is, the amount of dust in the air. It should be cleaned once every 3 to 6 weeks, and cleaned once every 6 to 8 weeks with low dust content. The stainless steel filaments, after washing with the alkali washing method, should be evenly laid into the frame of the air filter and sprayed with light spindle oil or vacuum pump oil.