Applications
Industrial Gas Purification
Trace contaminant polishing and drying — adsorption materials and molecular sieves matched to the impurity.
Two purification problems
Gas purification splits into two duties that look similar but select very different materials:
- Trace contaminant removal — ppm-level impurities (VOC traces, CO₂, H₂S, NH₃) polished from a gas stream. Selection depends on the impurity's molecular size and the gas's humidity: activated carbon for organic traces, zeolites for size-selective separation.
- Drying — water removal to a dew-point target. Molecular sieves win here: 3A reaches deep dew points (to −70°C and below) by excluding everything except water, 4A co-adsorbs small molecules for general drying.
Material routes
Zeolite molecular sieves
Size-selective: 3A/4A for drying, 5A/13X for separation and purification.
Activated carbon
Organic trace polishing in gas streams — columnar and honeycomb forms.
Modified zeolites
NaY and modified 5A/13X for specific separation and purification duties.
Selection checklist
- The impurity — name it and its concentration. "Purification" is not a specification.
- The target — outlet concentration or dew point, with the test method.
- The co-adsorbates — what else is in the gas that would compete (water vapor especially).
- The regeneration route — molecular sieves regenerate at 200–350°C; carbon within its own limits (below 120°C hot-air per HJ 2026-2013).
Name the impurity, we name the sieve
Impurity, concentration, target and gas composition — the four inputs of a purification spec.