Liquid Phase Molecular Sieve Dehydration
Drying Ethanol with Molecular Sieves
This Liquid Phase Design passes a liquid stream of wet alcohol or solvent through a column filled with molecular sieve beads.
As the liquid passes through the bed of sieve beads, the water molecules gets sucked into the beads. This occurs due to polar attraction. The internal surfaces of the molecular sieve adsorbs more of the water as the bulk liquid flows through the column. This continues until essentially all of the water is removed and the dried alcohol (or solvent) exits the column.
This process continues until the sieve becomes saturated with water, at which time the molecular sieve must be changed, or regenerated.
Regenerating the sieve typically involves 1) draining the liquid, 2) heating the sieve beads, 3) purging the gas either at pressure or under vacuum, and lastly, 4) cooling the sieve.
Wintek’s Internally Heated Short Path(SP) Design
Wintek’s unique MSDUL Liquid Phase Molecular Sieve design utilizes internal heating for temperature swing regeneration, which offers the following advantages:
- Very Dry Product to less than 10 ppm
- Low energy consumption
- Very high product recovery due to the low purge gas requirements: >99% recovery
- Very high thermal efficiency with the short gas path for thermal transfer
- High thermal efficiency means shorter regeneration cycle
- A shorter regeneration cycle enables higher processing rates
- Packaged units are fully piped and wired
- Fully automated, reducing operator
Externally Heated MSDUs
In Externally Heated MSDU Designs, purging hot dry gas (generally Nitrogen) through the bed, or circulating a hot gas with a partial purge heats up the mole sieve beads.
Externally heated designs suffer from long regeneration times due to the low heat content of the nitrogen being used to heat and cool the bed and the relatively large amount of energy required to change the temperature of the beds.
Even though condensers are used, this design suffers from higher emissions due to relatively high purge gas rates which are exhausted with saturated vapors.