Gasoline from Biomass without Fermentation
Most processes currently envisioned to produce alcohols from biomass depend on fermentation. That is, a living organism, often optimized through genetic engineering, converts the sugars or starches to alcohols. Besides being slow, the process usually takes place in a dilute system leading to an expensive water removal step. Virent Energy Systems of Madison, Wisconsin appears to have come up with a non-fermentation process which uses a number of catalytic steps. They estimate it could be economical at oil prices above $60 per barrel, which is the case most of the time today. In partnership with Royal Dutch Shell, they are currently operating a demonstration plant
Not to get too “chemical engineering” on you, the heart of the process is a step called Aqueous Phase Reforming (APR). A mix of sugars and other molecules derived from biomass is subjected to APR. Under relatively mild conditions, hydrogen, alcohols, and other hydrocarbons are produced. This stream can then be fed to a number of known, commonly practiced catalytic operations. It looks like a refinery. Depending on the processes utilized, gasoline, kerosene, jet fuel, or diesel can be produced.
The processing scheme appears to have a number of advantages:
- No energy intensive water separation step as in fermentation
- Commonly accepted catalytic steps currently practiced by refineries or chemical plants
- Produces a wide range of fuels that can be blended into current products.
- Products have higher energy density than ethanol and present no storage or transportation issues.
- Generates its own hydrogen for use in some of the catalytic steps.
If you’re into the technical aspects, Virent has published a white paper.