ATRP HOME

Gaining New Ground on Biodiesel Conversion Efficiency

IN THIS ISSUE Gaining New Ground on Biodiesel Conversion Efficiency The Economics of Biofuels Georgia Tech Students Study Biodiesel Production Using Algae High School Student Produces Homemade Biodiesel Using Restaurant Fryer Oil Defining Strategies to Control Storm Water Runoff from Poultry Processing Facilities Researchers Develop Process to Recover Eggshell Waste for Alternative Uses A Look at the Department of Homeland Security’s Chemical Facility Anti-Terrorism Standard and Its Impact on Poultry Processors and Growers Changing Environmental and Energy Climate Creates New Opportunities for Electric Boilers and Water Heaters Bringing the Research Lab to the Classroom

Growing concerns over global warming coupled with increasing crude oil prices have sparked national interest in alternative fuel sources. Many think that a biofuels boom-and-bust scenario is under way because so many start-ups have entered the market and oil prices are volatile. But any breakthrough in one of three areas will dramatically enhance the viability of biofuels. Those areas are identifying feedstock materials that do not compete with food processing needs, improving conversion efficiencies, and finding better ways to get more energy out per pound while using less energy. Researchers at Georgia Tech are focusing on improving conversion efficiencies.

Chemist Robert Wallace determines the energy content of a sample of biodiesel using a state-of-the-art calorimeter.

“We are interested in improving conversion and producing higher yields from valuable but problematic feedstocks, specifically poultry processing byproducts,” says John Pierson, a principal research engineer in Georgia Tech’s Food Processing Technology Division and head of the division’s Food Safety, Environment, and Energy Technology group.

“We are working to develop a one-step process for converting feedstocks that contain high levels of free fatty acids into biodiesel, and hopefully, ‘drop-in’ diesel or a kerosene equivalent,” adds Pierson.

Currently, the most common feedstock materials for biodiesel production in the United States are refined soybean oil and yellow grease (primarily recycled cooking oil from restaurants). Unrefined and waste oils are targeted as feedstocks for biodiesel production, but each contain free fatty acids (FFA), and each percent of FFA decreases the yield of biofuel production by an equal amount. Used and/or degraded sources such as yellow grease require filtering followed by water and FFA removal to prevent soap formation that occurs under conversional processes. A two-step process employing acid catalysts prior to base-catalyzed transesterification is used to reduce FFA levels.

“Water is chemically produced during most production processes, but it really slows the conversion of free fatty acids. We are looking at ways to remove water as well as use solid-acid catalysts as replacements for the liquid alkaline and acid chemistries currently used in traditional processes,” explains Robert Wallace, a chemist working together with Pierson.

“Many start-up biofuel companies do not realize that the poultry and allied industries already have a business model for getting value out of processing byproducts. The start-ups are another customer for stabilized or feed-grade poultry fat. But these products have FFAs that can be problematic for traditional biodiesel production, and depending on the rendering processing scheme used, result in brown grease as a byproduct-byproduct. If successful, our research will give the industry other options for converting lower value byproducts into higher margins,” notes Pierson.

According to Pierson, process benefits include free fatty acid recovery as a value-added material available for use in other applications, including lubricants, emulsifiers, plasticizers, and similar products currently obtained from petroleum products.

Photography by Steven Thomas, GTRI.