How do you determine when activated carbon needs replacement?

Activated carbon reaches adsorption saturation after a period of use and requires timely replacement. Here are several methods to determine when replacement is necessary:

1. Outlet Concentration Monitoring

In waste gas or wastewater treatment systems, if the outlet concentration of the treated stream approaches or reaches discharge limits, it indicates that the activated carbon's adsorption capacity has significantly declined, and replacement should be considered.

2. Pressure Drop Changes

In fixed-bed adsorption systems, a significant increase in the pressure drop across the activated carbon bed may indicate pore clogging, signaling a need for replacement.

3. Operational Duration

Track the duration of activated carbon usage based on historical data. When the operating time approaches the average replacement cycle for the specific operating conditions, schedule an inspection or proceed directly with replacement.

4. Periodic Sampling and Testing

Periodically (e.g., quarterly) sample and test the activated carbon for iodine value or methylene blue value. Replacement is recommended when the measured value drops by more than 30%–50% compared to the initial value.