Molecular Sieves to purify Ethanol

The ethanol vapors coming from the top of the distillation towers is about 98% ethanol, 2% water, plus some impurities. Most of the remaining water is removed by molecular seives. The result is almost pure, fuel-grade ethanol.

Molecular seives are tanks that are filled with pellets of a ceramic material that is filled with tiny holes. The holes are just big enough to allow water to get in, but too small to allow ethanol molecules. So the pellets absorb water from the ethanol.

After the pellets are soaked in water, the molecular sieve tank is emptied of fluid. The pellets remain in the tank and they have a mixture of water and ethanol stuck to them. These are removed by heating to a high temperature. The vapor that comes off is rich in ethanol and is sent back through the distillation process.

The original molecular sieve tanks at Moses Lake, from atop the distillation tower.

Molecular seives operate in pairs, with one of them removing water from ethanol, and the other being regenerated. We have two more pairs of molecular seives on the property. These seives were bought in Missouri, and this is a photo of their installation there

This is one of Molecular Sieves at Moses Lake:.

The other three sieve tubes at Moses Lake.