How not to kill the molecular sieve

Like all processes in an ethanol plant, careful attention is required in ethanol dehydration units to care for the molecular sieve.

Molecular sieves are a critical part of the commercial ethanol production process. They allow ethanol to be dehydrated past 95 percent purity to nearly 99.9 percent, which is critical to meet the specifications for use as a fuel additive. Like all processes in an ethanol plant, careful attention is required in ethanol dehydration units to care for the molecular sieve (also referred to as mole sieve beads, desiccant or zeolite). Proper preventive maintenance, care during the actual operating process and awareness of what can cause long-term damage to the beads and vessel, or bed, are crucial. Proactively monitoring and maintaining sieve beads is imperative to ensure a long, efficient lifespan of up to 10

Don’t Wet the Bed

Great care should be taken to ensure the process stream reaches and remains in vapor phase when flowing into the vessel and during operation. If the vapor condenses back to liquid phase, it can severely affect the mass transfer dynamics of water into and out of the vessel, which leads to a reduced working capacity and possible damage to the beads. When a process stream in liquid phase enters an ethanol dehydration bed, water can form a layer around each bead, essentially coating it with liquefied water because of water’s cohesive properties. Beads coated in liquid water slow or completely prevent the adsorption of vapor phase impurities (water) from the desired, pure ethanol product stream. 

The above information is for customers’ reference only. Performance characteristics vary depending on specific application. please contact us by email at info@fznewmaterials.com if detailed application method for molecular sieve needed.