Marshall, Minn. — A new product idea can only succeed if the research bears it out. Glycerin, as a renewable fuel, didn’t pass the test.
Rose Patzer, a chemist who recently left AURI to be a renewable fuels instructor at Minnesota West Community College in Granite Falls, has been testing glycerin as a combustion fuel since early this year.
Supplies of crude glycerin, the primary byproduct of biodiesel production, have outpaced demand since Minnesota mandated a 2-percent biodiesel blend. It was an intriguing idea to use glycerin as a boiler fuel, and it generated national and international interest. But the results weren’t encouraging.
“Because of its lower energy value, crude glycerin just doesn’t have enough available energy to support a flame on its own,” Patzer says.
Tests were conducted in Redwood Falls at the Central Bi-Products plant, which is permitted to burn yellow grease in boilers. The plant is a division of Farmers Union Industries, LLC. FUI also operates FUMPA Biofuels, which produces 3 million gallons of biodiesel annually.
Crude glycerin contains more than 6,000 Btu per pound. Minnesota biodiesel refineries produce about 600,000 gallons of crude glycerin annually. With this additional supply on the market, glycerin prices have dropped to just a few cents per pound, sparking interest in finding new uses for the thick liquid.
Refined glycerin is an ingredient in hundreds of products, from soap to cosmetics. But no Minnesota biodiesel facility has the equipment to refine crude glycerin for those markets.
Patzer says glycerin has high levels of ash, metal, chlorine and water, but not enough energy to work as a stand-alone fuel. She said a blend of 10 percent glycerin and 90 percent yellow grease could power a boiler, but it caused a significant buildup in the burners, resulting in more clean-up downtime.
“This demonstration was very specific to (Central Bi-Products) boiler and fuel parameters,” Patzer says, “but it could be a guide. Boilers are made to run on certain fuels, so modifications would be necessary. While 100 percent glycerin didn’t work in this case, individual results may vary.”
Due to the poor performance, low-energy value, emissions concerns and buildup on internal parts that could cause wear and tear on expensive equipment, straight glycerin may have flamed out as a boiler fuel. Such is the nature of research.
Chemist Rose Patzer has not been encouraged by test results of burning glycerin, an abundant biodiesel coproduct, as a combustion fuel.
To obtain a final report on the glycerin combustion study, contact AURI’s Marshall office at (507) 537-7440.