Two teams of Wisconsin researchers, one from private industry and one from the University of Wisconsin-Madison, have each independently announced this month a revolutionary breakthrough that can make hydrocarbon fuels -- like gasoline, diesel fuel, and jet fuel -- from biomass products, like wood chips or grass cuttings, using a new energy-efficient catalytic process called aqueous phase reforming, or APR.
This is big. Gasoline and other fuels produced from non-fossil sources means no global warming potential.
The first group, Virent Energy Systems of Madison, WI, has been working under a National Science Foundation grant for Small Business Innovation Research. Dr. Paul Blommel and Dr. Randy Cortright led a team that made the initial discovery in early 2006, but just announced it this month at a conference at Iowa State. Virent owns, or has has applied for, at least 50 patents on their overall process.
The second team, from six researchers the UWM Chemical and Biological Engineering department, announced their independent discovery (of essentially the same process) in the September 18 edition of Science Express, the online version of the journal Science. The article will be published in the October 18 edition of Science as well.
The National Science Foundation currently has several videos up on their website discussing this new process and its implications. I'm going up with this right away rather than fight the embed issues, but go take a look. I'll embed them later if I can.
A whitepaper on the process from Virent estimates that this process will be cost effective at crude oil prices greater than $60 per bbl.
Unlike traditional biocatalytic processes (like ethanol production), which are limited to working with only one specific carbohydrate, APF is able to convert a broad range of carbohydrates into liquid fuels. That means it can use almost any kind of plant as a source, once it's reduced to water solubable form. The biomass could be corn stalks, straw, seed hulls, wood chips, sawdust, or even farm manure. It could also be purpose-grown biomass crops, such as alfalfa, switchgrass, miscanthus, or poplar. Many such biomass crops can be grown on marginal land unsuitable for grain production, thus limiting the impact on food prices.
The first step is to process the biomass to extract the sugars and starches they contain, using currently available processes. Wood, for example, undergoes pretreatment to separate cellulose, hemicellulose, and lignin. The cellulose and hemicellulose goes further down the processing line, while the lignin is burned in the processing plant to provide energy for the process.
Once separated, the carbohydrates undergo hydrogenation or hydrogenolysis, using either external hydrogen and/or hydrogen generated in the APR process itself. At this point, the the hydrolized carbohydrates are subjected to the APR process, which uses proprietary catalysts in a reactor at moderately high temperatures and pressures (450 to 575 K and 10 to 90 bar) to reform them into primary hydrocarbons such as ketones, alkanes, and aromatics. Further processing into fuel is analogous to the crude oil refining process.
Aren't we doing that now? What about ethanol?
Ethanol production has a number of drawbacks. Current ethanol biomass is almost all from corn, which is not very energy efficient (perhaps a 10-25% return on energy invested), and also also drives up the price of food. Cellulosic ethanol has the potential to use non-corn feedstocks and achieve greater energy returns, but the process is currently not mature. Ethanol is also less desirable than hydrocarbon for fuel, because it's partially oxygenated, which means it's more difficult to handle and store than gasoline, and carries less energy content per gallon.
The APR process produces deoxygenated hyrdocarbons, which have greater energy densities and can be transported and processed using the current fuel infrastructure.