While biodiesel is rapidly emerging as an environmentally-friendly alternative to petroleum-based diesel fuel, its production leaves behind glycerin as a by-product. Looking for a way to turn this common and low-value leftover compound into a useful commercial product, Galen Suppes, a University of Missouri professor of chemical engineering, developed a process to turn it into propylene glycol, a non-toxic agent that can be used in antifreeze as a safer alternative to the more common ethylene glycol. Not only does this process yield a more useful by-product, but has actually shown to increase the production yield of biodiesel as well. Suppes said this technology can reduce the cost of biodiesel production by as much as $0.40 per gallon. Part of the cost savings is realized through the lower pressure and less equipment-intensive processing method.
"The impetus for developing this process was based on feedback we received from the biodiesel community about three years ago," Suppes said. "In the near future, they were going to have to find a use for the glycerin. It really caught up with the entire industry. The price is really suppressed for glycerin in Europe, and it's on its way down here." Not only does this solve the problem of what to do with this product, but gives biodiesel producers another potential source of revenue.
"The price of propylene glycol is quite high while glycerin's price is low, so based on the low cost of feed stock and high value of propylene glycol, the process appears to be most profitable," Galen Suppes, professor of chemical engineering at Missouri said. He said an added bonus was the marketing appeal of non-toxic antifreeze to consumers, which using this process, could become much more widely available. "The consumers want antifreeze that is both renewable and made from biomass rather than petroleum from which propylene glycol currently is produced, as well as nontoxic."
Currently, Renewable Alternatives is licensing this technology to three biodiesel plants, with a fourth one in the works. The National Science Foundation and Missouri Soybean Farmers are helping fund the research, as well.