Ethanol Dehydration

The process of ethanol dehydration is commonly found in the CBD oil extraction industry. Ethanol extraction involves introducing ethanol as a solvent to the hemp or cannabis plant to extract the cannabinoids. Ethanol extraction can produce cannabis oil with up to 99% purity, meaning a higher quality end product than CBD oil extracted through other techniques. During this process, the ethanol accumulates water (~5-10% by mass), which renders it unsuitable for re-use. The process of ethanol recovery is essential to re-use ethanol.

The Purpose of MSDUs for Ethanol Dehydration

The separation of water and ethanol is particularly challenging due to the formation of an azeotrope at ~95 volume % ethanol/water. At this particular concentration of ethanol and water at atmospheric pressure, further component separation cannot be achieved by traditional means because the composition of components in the liquid phase and gas phase are equivalent. There are a few ways to get around this limitation; however, Wintek focuses on the physical separation technique that utilizes molecular sieves. Molecular sieves are synthetic beads with small pores. The pores are large enough to allow water molecules to pass through, but small enough to restrict the flow of ethanol into the beads.

The beads become saturated with water, while the dry ethanol passes through the system. Using a pressure swing and high temperatures, the water within the beads can be vaporized and the beads re-used for further separation. This technique is a physical separation, which means the azeotrope does not limit the amount of water able to be removed.

Wintek designs and operates Ethanol Dehydration Molecular Sieve Dehydration Units (MSDUs) custom-designed to remove water content to allow for ethanol recycling/re-use.

Wintek’s Ethanol MSDUs Are Highly-Efficient Designs Providing:

  • Ability to process from ½ gpm to over 25 gpm of wet alcohols and solvents
  • 90-95% solvent recovery rates
  • Energy consumption less than competing technologies
  • Minimal operator intervention
  • Ability to handle a wide variation in feed concentrations (0-10% water by volume, up to 15% possible).
  • Provide high purity: Standard Dryness: >99.5% (<5,000 ppm water)
gas phase msdu molecular sieve dehydration unit
Wintek SN 130114: Ethanol dehydration MSDU, 1.75 gpm methanol/water mix with 5.0 wt% water, dehydrated to 99.5 wt% water