Virent Pulling Ahead of the Pack?
The National Advanced Biofuels Consortium
In January 2010, Energy Secretary Steven Chu announced the investment of nearly $80 million under the American Recovery and Reinvestment Act for advanced biofuels research and fueling infrastructure. About $35 million of the funding went toward the National Advanced Biofuels Consortium (NABC). The consortium consists of 17 partners from industry, national laboratories, and universities with the goal of producing economical biofuels that are compatible with existing infrastructure (drop-in fuels). The consortium is investigating “six process strategies with the greatest potential to meet the project objectives. Each process involves converting biomass feedstock, such as corn stover or wood chips, into a form that can be used in a petroleum refinery. These new and innovative approaches can advance the commercialization and adoption of advanced biofuels.”
The six strategies that are being investigated are:
- Fermentation of lignocellulosic sugars
- Catalytic conversion of lignocellulosic sugars
- Catalytic fast pyrolysis
- Hydrothermal liquefaction
- Syngas to distillates.
The NABC describes the process of elimination that the processes will undergo:
During Stage One, the consortium will research all six process strategies to determine whether technical and economic barriers can be overcome to develop a pilot-ready process in a three-year period. Sustainability and technoeconomic analyses will guide the research program. After one year, the consortium will perform a feasibility study that will determine which process strategies are most likely to succeed. One to three strategies will be selected for further research and development.
In Stage Two, the selected processes will be moved toward the pilot scale. The National Advanced Biofuels Consortium will engineer processes to be integrated with current petroleum refining infrastructure. At the end of the three-year project, the consortium will deliver a technology package that includes a pilot plant-ready process, a detailed design and engineering report, and a life-cycle analysis.
An Introduction to Virent Energy Systems
Jim Lane, editor and publisher of Biofuels Digest, characterized the process as “a biofuels R&D version of Survivor.” One of the companies participating in the consortium is Virent Energy Systems (Virent), and their process falls under the category of “catalytic conversion of lignocellulosic sugars.”
Virent’s strategy is unique among biofuel companies. It starts with a hydrolysis process. Hydrolysis in this case is the process of breaking down cellulose — which consists of long chains of sugar polymers — into individual sugars. This is the same sort of process at the front end of a cellulosic ethanol process.
But the similarities end there. With a cellulosic ethanol process, what follows the hydrolysis process is a fermentation of the sugars, similar to what takes place with corn or sugarcane ethanol. There are some fundamental problems with the cellulosic process that have resulted in some difficulty commercializing the process. Virent’s process gets around those fundamental problems.
Instead of using microbes to turn sugars into fuel, Virent uses a thermochemical process that is much less sensitive than is a microbe-based process. Virent feeds the sugars that are produced in the hydrolysis step into an aqueous phase reformer (APR), where the sugars are turned into oxygenated compounds like ketones, acids, aldehydes, and alcohols. Following the APR step, the compounds undergo condensation using catalytic technology proven in today’s refineries to form hydrocarbons, that are the basis of gasoline, diesel, and jet fuel.
In laymen’s terms, the Virent process takes biomass, uses conventional techniques for releasing the sugars, feeds that to their proprietary refining process, and then finishes up with processes found in most oil refineries.
Virent has made progress in developing their technology, and recently issued the following press release:
Madison, Wisconsin June 2, 2011 – Virent announced it has successfully produced biogasoline from corn stover and pine harvest forest residuals, as a recipient of the U.S. Department of Energy’s February 2010 grant to the National Advanced Biofuels Consortium. Virent’s achievement supports the NABC’s goal to develop technologies to convert cellulosic biomass feedstocks into hydrocarbon fuels that are compatible with existing infrastructure.
Virent’s Catalysis of Lignocellulosic Sugars is one of six different process strategies represented in the DOE’s grant program with the NABC. The CLS strategy work to date was completed in collaboration with Catchlight Energy (pine material supplier), Iowa State University (corn stover supplier), with Washington State University performing oxidation and enzymatic hydrolysis treatments necessary to digest cellulose for these two samples. The National Renewable Energy Laboratory (NREL) supplied two additional hydrolysate samples which underwent a dilute sulfuric acid pretreatment and enzymatic hydrolysis process for its breakdown of the cellulose. Virent then processed the four hydrolysate samples using its BioForming process.
Virent fed each of the four hydrolysate samples into its Aqueous Phase Reforming (APR) catalyst reactor system, removing most of the oxygen from the biomass sugar mixtures, producing monoxygenates such as alcohols, aldehydes and ketones, plus the reforming products of hydrogen and carbon dioxide. Virent’s APR process is suited to handle mixed sugars from cellulosic streams with minimal processing. The liquids were then fed into Virent’s Catalytic Oxygenates to Aromatics (COTA) process to produce a high octane biogasoline, which the company has trademarked BioFormate.
“Producing gasoline from cellulosics is an important milestone for our company, and for the biofuels industry overall,” said Dr. Randy Cortright, Virent’s founder and chief technology officer. “We anticipate further development in our production of drop-in fuels and chemicals from biomass, giving our nation long-awaited access to a wider range of feedstock choices.”
The process that Virent is developing is intriguing to say the least. However, as always it is necessary to dig down a few layers to flesh out any formidable technical challenges that could prevent commercialization. Luckily, Virent made Dr. Randy Cortright — their Chief Technology Officer — available to me for answering some questions about Virent’s process. In the next essay, I will delve deeper into Virent’s story in an attempt to figure out if their process is as good as it seems on the surface.