What are the factors that cause paddle dryer corrosion?

What are the factors that cause paddle dryer corrosion?

When the paddle dryer is used for a long time, the paddle dryer will appear the phenomenon of corrosion, then, what causes this phenomenon?

a, biaxial paddle dryer corrosion is mainly due to the production of biaxial paddle dryer material is metal, and the chemical activity of the metal are relatively high, when the metal is exposed to the humid air for a long time, the metal will undergo oxidation, and then corrosion occurs. Double shaft paddle dryer is made of different metal materials, their oxidation reaction occurs easily is different.

b, the more pure metal made of biaxial paddle dryer is less likely to be corroded, when the more impurities in the metal, biaxial paddle dryer is more likely to be corroded.

c, when the shape of the internal parts of the biaxial paddle dryer is more complex, the rougher the surface, then its corrosion resistance is worse, when the internal parts corrosion occurs, will soon cause contact with the parts of the place of metal corrosion, and corrosion rate is very fast.

d, when the working environment of the biaxial paddle dryer high temperature, high humidity, or the environment of oxygen, chloride ions, it is easy to chemical reaction with the biaxial paddle dryer, accelerate the degree of corrosion of the biaxial paddle dryer.

What are the main uses of paddle dryer?

In fact, at present, the paddle dryer has been successfully applied in the fields of food, chemical, petrochemical, dyestuff, industrial sludge and so on. By indirectly heating or cooling the paste, granule, powder and slurry materials, the paddle dryer can complete the unit operation of drying, cooling, heating, sterilizing, reacting and low temperature combustion. The special wedge-type stirring heat transfer slurry blade in the equipment has high heat transfer efficiency and self-cleaning function of heat transfer surface.

In addition, the equipment has the characteristics of heat transfer, cooling, stirring function makes it possible to complete the following unit operations: combustion (low temperature), cooling, drying (solvent recovery) heating (melting), reaction and sterilization. Stirring the slurry blade at the same time is the heat transfer surface, so that the unit effective volume of heat transfer area increases, shortening the processing time. The heat transfer surface of the wedge-shaped blade is also self-cleaning. The compression-expansion stirring function makes the material mix evenly. Material along the axial into the “piston flow” movement, in the axial zone, the material temperature, humidity, mixing degree gradient is very small. With heat conduction oil as the heat medium slurry dryer can complete the low-temperature combustion work.

For example: Calcium sulfate dihydrate (Ca2SO4-2H2O) combustion into calcium sulfate hemihydrate (Ca2SO4-1/22H2O). Sodium bicarbonate (NaHCO3) is converted into soda ash (Na2HCO3) by calcination, etc. Passed into the cooling medium, such as water, cooling brine, etc. can be used for cooling. For example, the slurry leaf cooler used in the soda ash industry replaces the old air-cooled cooler, saving energy and exhaust gas treatment equipment and reducing operating costs.

Paddle dryer for the need to recover solvents, flammable and oxidizable thermosensitive materials are particularly adaptable. Has been widely used in fine chemicals, petrochemicals, dyes industry. The uniformity of temperature, humidity, and mixing degree in the axial interval makes the equipment available for heating or melting, or for some solid material reactions. It has been successfully used in compound fertilizer and modified starch industries. Slurry dryers can be used to sterilize food and flour. The large heating area in the unit effective volume quickly heats the material to the sterilization temperature and avoids changing the quality of the material by heating for a long time.

Paddle dryer is especially suitable for continuous drying of paste and slurry materials, such as printing and dyeing sludge, electroplating sludge, etc. After drying by paddle dryer, it finally becomes powder granule with very low moisture content.