|The BNRI membrane assembly. Click to enlarge.|
Mitsui Engineering & Shipbuilding Co. will use a zeolite membrane developed by Mitsui & Co. subsidiary Bussan Nanotech Research Institute Inc. (BNRI) in dehydration systems for bioethanol plants.
Dehydration systems are used in the production of ethanol to remove water from the output. The most common method of removing water involves adding heat, but this increases energy consumption and carbon dioxide emissions.
The BNRI filter concentrates the ethanol by allowing only water to pass through the membrane, thereby helping to reduce process fuel consumption by around 10% compared to other methods. Mitsui and Mitsui Engineering will sell the systems in major ethanol producing countries such as Brazil and the US.
Zeolites are well known materials used as absorbents, catalysts or ion exchangers. However, the large-scale production of zeolite membranes without defects had proven elusive, according to BNRI. BNRI claims to have developed such zeolite membranes.
The membrane consists of a 3-D mesh-like structure where silicon oxide and aluminum oxide covalently share oxygen atoms. Its mesh “eyes” stack regular array of tiny pores in 3-D space. Those pores form channels at 0.4 to 0.8 nm width.
The membrane is supported on a ceramic tube. Water from the water-ethanol mix passes through the filter and into the tube. The ethanol flows out through a separate channel.