What substances are harmful to desiccant rotors?

Following substances are known to be harmful to rotors if they come in contact with the material. Always consult COTES when there are foreign substances present in the air seeing that the list is based on our and our suppliers’ experience so far and new pollutants might have to be added. The effect can depend on the concentration where low concentrations might be accepted. In all cases, the air must be filtered before entering the dehumidifier and subsequently the rotor.

Acids will damage the supporting structure, known examples hereof:

• Hydrogen Fluoride
• Sulfuric acid
• Hydrochloric acid
• Formic- and acetic acid

Bases will degrade the silica gel structure, known examples hereof:

• Ammonia
• Amines
• Sodium hydroxide
• Potassium hydroxide

Other harmful substances that are known to damage rotor structure:

• Sulfur dioxide and –trioxide higher than 40 ppm.
• Acetone at high concentrations
• Xylen
• Glycerin
• Gases of high boiling organics (b.p. higher than 175 ⁰C)
• Oil vapor and mist
• Exhaust from diesel engines at high concentrations
• Water droplets and mist
• Steam from heaters
• Cement (can be avoided with good filtration)
• Sugar (can be avoided by good filtration)
• Wood resin and lingnins

Further, chlorine containing compounds will degrade rotor material and will also corrode metal parts very rapidly.