Molecular Sieve Grades And How To Select One

Start From The Duty, Not The Type Number

Most enquiries arrive asking for 13X. Sometimes that is right, but three application-specific series exist precisely because the generic types leave performance on the table. Oxygen enrichment points to the JLOX series. Cryogenic air separation points to JLPM molecular sieve with JLAZ activated alumina ahead of it. Hydrogen purification points to the JLPH series. Only when the duty is general drying or purification is a plain 3A, 4A, 5A or 13X the right answer.

What The Generic Types Do

The number is the nominal pore aperture in angstroms and the letter is the framework. 3A excludes almost everything except water, which is why it is used for drying unsaturated hydrocarbons and insulating glass. 4A admits water and small molecules. 5A admits straight-chain hydrocarbons and is used for separations based on molecular shape. 13X has the largest aperture of the four and the highest capacity for water and carbon dioxide.

Powder Versus Formed Product

Synthetic zeolite powder is the input to catalyst manufacture and to formulated products; formed beads and pellets are what go into an adsorber vessel. Both are supplied here. The speciality powder list runs well beyond the standard types and includes NaLSX, MSX, LiLSX, CaX, CaLSX, nm-A and nm-X, along with ZSM-5 and NaY for catalyst work.

Activated Alumina As The Pre-Layer

In most air separation and gas drying designs, activated alumina takes out the bulk of the water and molecular sieve finishes the job. Alumina is the cheaper bulk pre-dryer, sieve is the polishing layer. JLAA is the general grade, JLAZ is the cryogenic air separation series, and JLAA-HN is a high sodium grade. Buying both layers from one source keeps the interface between them consistent.

Capacity Matters For Supply Security

Published annual capacity is 42,000 tons of molecular sieve, plus a further 12,000 tons at a plant in Thailand, 41,000 tons of synthetic zeolite powder and 5,000 tons of activated alumina. Two production locations on a critical adsorbent is worth knowing about when a single-plant supplier has an outage.

What To Send With An Enquiry

Gas composition, operating pressure, operating temperature and cycle time. Those four pieces of information are what a grade recommendation is actually based on. Bead size, packing and lot quantity are confirmed per order, and a batch certificate of analysis should be requested with each shipment.