NAMS 2002 Workshop - ICOM 2008

Pervaporation and Vapor Permeation I – 1 – Keynote
Tuesday July 15, 8:15 AM-9:00 AM, Honolulu/Kahuku
Bioethanol Production Using Pervaporation and Vapor Permeation
Membranes
I. Huang (Speaker), Membrane Technology & Research, Menlo Park, CA, USA,
ihuang@mtrinc.com
R. Baker, Membrane Technology & Research, Menlo Park, CA, USA
L. Vane, The U.S. EPA, Cincinnati laboratory, Cincinnati, OH, USA
Bioethanol production for use as a renewable energy resource is booming driven
by climate change concerns and soaring oil prices. Conventional
distillation/molecular sieve drying of bioethanol uses about 20% of the energy
content of the ethanol produced. Alternative technologies which consume less
energy to dehydrate ethanol are of considerable interest to the bioethanol
industry. The existing membrane technology for ethanol/water separations uses
pervaporation. The first industrial-scale pervaporation unit was installed in Brazil
by GFT (now Sulzer Chemtech) in 1982 to dehydrate ethanol from a cane sugar
fermentation plant. Despite this early success, pervaporation has not been widely
used in bioethanol production, primarily because the membrane modules used
were too expensive and were susceptible to slow degradation, leading to
excessive replacement costs.
In this paper, the application of pervaporation and vapor permeation to
bioethanol membrane separations is described. Novel, low energy process
designs require membrane modules able to operate at high temperatures with
high water concentration ethanol solutions. The requirements for membrane
properties are discussed. The processes described showed significant energy
savings compared to the conventional distillation/molecular sieve drying process.