mSORB APGIII is a sodium type X zeolite bead, the 13X framework, developed for air separation plant prepurification units (APPU). Its nominal 10 angstrom pore admits both water and carbon dioxide, so as compressed air passes through the bed, water is typically held in the leading section and carbon dioxide further along, and dry air, free of carbon dioxide, passes on to the cold box. The grade is built around carbon dioxide capacity at the low concentration found in air, a few hundred parts per million, because carbon dioxide breaking through the bed is typically what ends each adsorption step. The bed is then regenerated with a heated purge and returned to service, with vessels typically alternating so that the air supply runs continuously.
Chemical Formula: Na₈₆[(AlO₂)₈₆(SiO₂)₁₀₆]·nH₂O
TYPICAL APPLICATIONS
mSORB APGIII is designed for the prepurification units at the front end of cryogenic air separation plants:
- New prepurification unit designs
- Change-outs of spent sieve in units already in service
- Revamps of existing prepurification units
SIZES AND PACKAGING
- mSORB APGIII 8x12 mesh beads, 1.9 to 2.3 mm, product code 13X812B-APGIII
- mSORB APGIII 16x40 mesh beads, product code 13X1640B-APGIII
The 8x12 beads ship in 330 lb (150 kg) drums and in super sacks; the 16x40 beads ship in 308 lb (140 kg) drums.
FREQUENTLY ASKED QUESTIONS
What is APGIII molecular sieve?
mSORB APGIII is Interra Global's air plant grade of 13X molecular sieve, a sodium type X zeolite bead made for the prepurification units that clean feed air before cryogenic separation. APG stands for air plant grade. The grade is supplied as 8x12 and 16x40 mesh beads.
How does APGIII differ from standard 13X molecular sieve?
Both are the sodium form of the type X zeolite. mSORB APGIII is the grade intended for prepurification duty, and its data sheets rate its carbon dioxide capacity for that service. The sheets state a 50 percent higher dynamic carbon dioxide capacity than the original mSORB APG grade. Standard mSORB 13X serves general gas drying and sweetening as well as prepurification.
Why does air need prepurification before cryogenic separation?
Water and carbon dioxide freeze at the temperatures inside a cryogenic air separation plant, and ice or solid carbon dioxide would foul its heat exchangers and columns. The prepurification unit removes them from the compressed feed air before it enters the cold box. Many units layer the bed, with activated alumina taking most of the water ahead of the molecular sieve.
What does higher carbon dioxide capacity mean for a prepurification unit?
More carbon dioxide held per unit of bed typically allows a new unit to be designed around smaller adsorber vessels, and an existing unit to run longer between regenerations or treat more air in the vessels it has. What a given unit can take depends on its design and operating conditions, and Interra Global reviews a unit's history and service conditions when called on.
How is APGIII regenerated?
With a heated, dry purge gas that carries the adsorbed water and carbon dioxide out of the bed. The product data sheets state that mSORB APGIII can be regenerated by purging at elevated temperatures or at compressor waste heat temperatures; the conditions a given unit uses depend on its design.
How should APGIII be stored before loading?
Indoors, in a dry location, in its sealed packaging. Molecular sieve takes up moisture from the surrounding air, and moisture adsorbed before loading typically costs the bed capacity until its first regeneration. Reseal drums and super sacks once opened, and use the oldest stock first.