Turning Alcohol into Drop-in Biofuels
At the existing Boardman, OR demonstration facility, we will add process modules to enable the conversion of alcohol into drop-in hydrocarbon fuels (alcohol-to-hydrocarbon, or ATH), including jet and diesel fuel as well as bio-based gasoline. This is accomplished in a three-step process:
- Dehydration of ethanol to ethylene
- Oligomerization of ethylene to distillate boiling range olefins
- Hydrogenation of olefins to produce paraffinic fuel blendstocks
At elevated temperatures, ethanol is fed through a catalyst to produce ethylene and water. These two products are easily separated. The water is treated and can be recycled within the biorefinery, while the ethylene goes on to make fuel.
The word oligomer comes from the Greek word oligos, meaning “a few.” The oligomerization process combines a few ethylene molecules into one larger hydrocarbon unit that is similar in size to the molecules in petroleum based fuels. Depending on the type of fuel, the new hydrocarbon molecule is from 8-to-10 carbon atoms long.
Finally, the large hydrocarbon unit is a new molecule made by chemically combining ethylene. The molecule is saturated with hydrogen to make the drop-in replacement biofuels.