How to prevent scaling of the tube bundle of the tube bundle dryer?

1. Feed pretreatment
Filter impurities: Before the material enters the tube bundle dryer, set up an effective filtration system. Select a suitable filter according to the nature of the material and the type of impurities it may contain. For example, for liquid materials containing solid particles, a screen filter can be used. The pore size of the screen is determined according to the particle size, generally between tens of microns and hundreds of microns, so that most of the solid impurities can be intercepted and prevented from entering the tube bundle dryer and adhering to the tube bundle to form a scale layer.
Control material composition: Understand the chemical composition of the material and pre-treat the components that are prone to scaling. If the material contains calcium, magnesium and other ions, softening treatment can be considered before feeding. For example, for aqueous solutions containing more calcium and magnesium ions, ion exchange resins can be used for softening. Through the ion exchange resin bed, the calcium and magnesium ions in the water are exchanged with the sodium ions in the resin, thereby reducing the concentration of calcium and magnesium ions in the water and reducing the possibility of scaling on the surface of the tube bundle.
2. Optimize operating parameters
Control material humidity and temperature: During the drying process, reasonably control the humidity and temperature of the material. Avoid materials entering the tube bundle dryer at too high humidity, because high-humidity materials are prone to form an adhesion layer on the surface of the tube bundle, which in turn causes scaling. At the same time, set the appropriate drying temperature according to the nature of the material and the drying requirements. If the temperature is too high, some components in the material may undergo chemical reactions and produce new scaling substances. For example, when drying food materials containing sugar, too high a temperature may cause the sugar to caramelize and adhere to the tube bundle to form a scaling layer.
Adjust the material flow rate and residence time: The appropriate material flow rate and residence time in the tube bundle dryer can help reduce scaling. Too slow a flow rate may cause the material to stay on the surface of the tube bundle for too long, increasing the risk of scaling; too fast a flow rate may cause the material to not be fully dried. Determine the optimal material flow rate and residence time through experiments and actual operating experience. For example, when drying granular chemical raw materials, the material flow rate can be controlled within a certain range so that the material stays in the tube bundle dryer for 30-60 minutes, which can both ensure the drying effect and reduce scaling.
3. Regular maintenance and care
Regularly check the condition of the tube bundle: formulate a regular inspection plan to check the surface condition of the tube bundle. The scaling inside the tube bundle can be checked by tools such as endoscopes. For example, every month or a production cycle, open the inspection port of the tube bundle dryer and use an endoscope to check some areas inside the tube bundle to detect the initial scaling phenomenon in time so that appropriate measures can be taken.
Cleaning and maintenance: Even if preventive measures are taken, the tube bundle may still have a certain degree of scaling, so regular cleaning is essential. Determine the cleaning cycle based on the possibility of scaling and production conditions. For materials that are prone to scaling, the cleaning cycle can be appropriately shortened. The cleaning method can be a combination of chemical cleaning and physical cleaning, such as soaking with a chemical cleaning agent first, and then flushing with high-pressure water to ensure that the scale layer on the surface of the tube bundle is completely removed.