Ethanol Dehydration

Ethanol Dehydration

Why does using Hengye Molecular Sieve for Ethanol Dehydration matter?
Aside from producing fuel grade ethanol, Ethanol Plants also produce CO2 and distillers grain as operations are focused on efficiency and sustainability.
Molecular sieve is widely used in the biofuel industry for removing water from ethanol in the generation process. EthaDry, a Hengye Inc. product, has been designed specifically for use in ethanol production, and when handled correctly in a system that is properly operated throughout its working life, can improve an ethanol dehydration unit’s dynamic adsorption capacity of water, raise ethanol output, while reducing by-products.

Quality Ask to see our Certificates of Analysis from recent production lots, which supplement our provided specification sheets.

Efficiency The Hengye Inc. team will calculate the efficiency of your system upon request and explain the various physical attributes of molecular sieve to assist in your decision making.

Technical Support A top priority at Hengye Inc. is to give our customers end-to-end Technical Support over the long term so that customers have the right product for the task at hand.

Cost Savings With large amounts of product in your ethanol dehydration system, it’s easy to understand how small differences in temperature or a miscalculation from product quality can lead to significant losses or gains in profitability and at Hengye Inc. we will support you every step of the way.

Properties and Mass Transfer

The Mass Transfer Zone (MTZ) is strongly effected by the properties of the molecular sieve being used. Bulk density will change the speed at which the beads become saturated and can alter both cycle time and the overall adsorption capacity of the bead. If the Mass Transfer Rate (MTR) is slow, the MTZ is increased, which causes a breakthrough to occur while much of the bed still remains useful. An faster MTR is ideal for getting the most use out of your dehydration units each cycle.

Dehydration Units

Through distillation alone, ethanol can only be dehydrated to around 95% to 97% purity, with the remaining water unable to be removed due to the formation of an azeotrope. This phenomenon leaves the ethanol unsuitable for use as a fuel or additive. To achieve fuel purity ethanol, pressure swing adsorption (PSA) technology, along with the use of molecular sieve, is applied and anhydrous ethanol can be achieved.

The graphic above represents one ethanol dehydration bed. On the left, the bed has just began a dehydration cycle, with most of the bed in an active phase. As the cycle continues as seen in the middle of the image, the Mass Transfer Zone has moved downwards. The molecular sieve above the MTZ, the equilibrium zone, is saturated with water, while the remaining molecular sieve below the MTZ is still active. The far right of the image shows a dehydration bed approaching the end of its cycle, with most of the bed saturated with water and the active zone diminishing. At this point, the cycle would likely be ended (just before breakthrough occurs) and the bed would be prepared for regeneration.


EthaDry a molecular sieve for ethanol production

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