Activated Alumina for Air Dryer
“How do I know when to change my Activated Alumina?”, asked Dave from North Carolina. “Can I spit on it and tell?”
This is a common question, well not the spitting part, and Dave isn’t alone in trying to figure out if his activated alumina desiccant is still “working.” He just called our 800 number and I figured this was a good time to answer the “when to change desiccant” question for everyone.
Unlike other desiccants like silica gel which can change colors to indicate it can no longer be regenerated, there’s not a good way to test activated alumina desiccant. The most common method used in industry is if there is moisture starting to appear downstream, it’s probably time to change the desiccant.
However, with critical compressed air drying applications that require -40° dew point, manufacturers cannot take that risk. They use moisture indicator sensors and alarms to alert them when the dew point has gone outside of the desired range. For compressed air dryer applications that only require 0° dew point, a simple moisture indicator that changes in color can be used.
Activated Alumina desiccant is typically good for three to five years before it needs to be replaced. It depends on many factors including air flow, temperature, hours used, cycle time, required dew point, etc. If your Activated Alumina desiccant has become discolored and is no longer white or off-white, you may have a faulty or clogged pre-filter, or it could also be an indication that your Activated Alumina needs replaced.
Do you have a question like this? We might have an answer. Call us at 800-551-0774 or contact us with your compressed air drying questions.
(If you don’t know how long it’s been, you should just Buy Activated Alumina Desiccant.)