Raise Your Glass: The Connection Between Brewing and Driving
It's a Thursday evening in downtown Clemson. The night is young, and many students are enjoying one of their favorite beverages. Alcohol flows as the lifeblood for many a college party, but the mechanics behind its production could yield new frontiers in the future of renewable energy. In its second semester, Dr. Terry Walker, Dr. Tim Teitloff, and David Thornton's Creative Inquiry takes students through the process of zymology, the science of fermentation.
The team is an interdisciplinary combination between the School of Agriculture, Forestry, and Environmental Sciences, Mathematical Sciences, and Environmental Engineering and Earth Science. Students first learn the basics of home brewing beer, then how this technology can be applied towards producing green energy.
Zymology is the science underlying ethanol production, which can be either a popularly consumed beverage if you're 21 and older, or a biofuel commonly found in your gasoline tank. David Carey, a junior chemical engineering student, explained his passion for the project by stating, "As someone who likes beer, loves science, and has a particular hankering for fiddling with experiments, I couldn't wait for the chance to combine the three into a delicious, illuminating, and personally intriguing venture."
When most people talk about biofuels, they typically think of ethanols derived from corn and soy. The problem lies in the fact that corn and soy are also food products, so the next step is to make ethanol out of materials that don't compete with other consumption needs. Nonfood plants include corn husks, pine straw, and switchgrass. The problem with using these other materials is that they contain a compound called lignin, which is tougher for yeast to digest and ferment.
Various methods are being researched in the bioenergy field to make lignin easier to process, including pressing the plant matter into a pellet or applying different types of pretreatments.
This Creative Inquiry started as a spinoff of the Green Energy and Biodiesel project. Before coming to Clemson, David Thornton previously worked on biorefineries for biodiesel. There, he met people in the grassroots biofuels movement who were developing small-scale biodiesel production systems for farms with common equipment. Since arriving at Clemson he has explored developing similarly affordable small-scale biorefineries for ethanol production. Carey noted, "Beer, and ethanol in general, plays a large role in today's society (in the forms of alcoholic beverages and sustainable fuel sources), but this is nothing new."
Ethanol can be burned directly in gasoline engines, or can be reacted with plant-based oils for a completely renewable biodiesel fuel. While the team doesn't have a model yet for ethanol production, the process is very comparable to something students might recognize: brewing beer. Both processes use similar methods.
These include preparation of plant matter, using enzymes and yeast to convert sugars to alcohol, analytics, temperature control, and sanitization. Starting materials for both are plant products, as beer uses barley and millet. For ethanol production the research team is testing sorghum, loblolly pine, switchgrass, and sweet gum grown at the Pee-Dee Research Station in Florence. Distillation further refines the product to make ethanol.
The team initially began by focusing on methods for converting starch into more usable sugars and monitoring the process. Recently, the students began working on designing and building an open-source model that can be scaled to the user's needs for semi automated production of 12-gallon batches of ethanol. The students design all of the equipment to FDA standards, including the processing vessel, stands, programming, and controls. Thornton says, "The idea of 'open-source' is sort of a collaboration of the University and Grassroots missions of creating accessible knowledge for wide-spread implementation of renewable energy solutions. All of our designs will eventually be posted to our website and blog."
In addition to producing a scale-up refinery, the team hopes to produce enough ethanol to completely displace the methanol currently used in Clemson's biodiesel production. "This will result in a 100% domestically produced renewable fuel with high energy content and better cold flow performance over our current methyl ester biodiesel," says Thornton. Because of the nature of this Creative Inquiry, students are required to be 21 or older to participate.