|Goals of the DuPont cellulosic biorefinery. Click to enlarge.|
DuPont broke ground on its cellulosic ethanol facility in Nevada, Iowa—among the first and largest commercial-scale cellulosic biorefineries in the world. DuPont contracted with Fagen, Inc. for the construction. (Earlier post.)
Once fully operational, the more than $200-million facility, expected to be completed in mid-2014, facility will produce 30 million gallons of cellulosic ethanol per year from corn stover residues; its fully integrated end-to-end production system will be available to license globally. This capacity is more than called for by original estimates as data derived from the piloting facility in Tennessee has allowed DuPont to further optimize its process and technology.
This first commercial facility will require a capital investment of about $7 per gallon of annual capacity.
Nearly a decade ago, DuPont set out to develop innovative technology that would result in low capital and low-cost cellulosic ethanol production. We recognized that science-powered innovation was the catalyst to make cellulosic ethanol a commercial reality and to help reduce global dependence on fossil fuels.
By leveraging DuPont Pioneer corn production expertise and designing an integrated technology platform, we’ve built an affordable and sustainable entry point into this new industry. We’re committed to continued productivity gains to drive costs down even further for the coming generations of plants, ones based on corn stover as well as other feedstocks.
We didn’t get to this point alone. We’ve built an incredible partnership with the state of Iowa, Iowa State University, entrepreneurial growers and a whole host of partners around the country who share our vision of making renewable fuels a commercial reality.— James C. Collins, president, DuPont Industrial Biosciences
DuPont’s cellulosic ethanol process consists of 5 stages: milling; pre-treatment; enzymatic saccharification; mixed sugar fermentation; and separation. The company developed an optimized technology package of novel enzymes and fermentation organisms to yield lower-capital integrated unit operations.
DuPont’s Accellerase TRIO enzyme complex—which can work with a wide range of feedstocks and pretreatment technologies—delivers all major enzyme activities required for efficient biomass hydrolysis into both C5 and C6 sugars, often at half the dosage of previous enzyme innovations, according to DuPont. (Earlier post.)
To supply the corn stover for its plant, DuPont will contract with more than 500 local farmers to gather, store and deliver more than 375,000 dry tons of stover per year into the Nevada facility. In addition to the estimated 60 full-time plant operations jobs, there will be over 150 individuals involved in the collection, stacking, transportation and storage of the stover feedstock seasonally during each harvest. The stover will be collected from an approximate 30-mile radius around the new facility and harvested off of 190,000 acres.
For many corn growers, residue management is a major challenge when maximizing their potential grain yield. Leftover corn stover interferes with planting, delays stand establishment, monopolizes nitrogen in the soil and often harbors damaging insect, pests and pathogens. Some stover from the corn crop is left on the field to protect the soil from erosion.
DuPont will further adapt its cellulosic ethanol technology to additional feedstocks. It is already processing switchgrass in the testing facility it owns jointly with the University of Tennessee near Knoxville, Tenn.
An International Organization for Standardization (ISO)-compliant, peer-reviewed life cycle assessment of the DuPont biorefinery and supply chain indicates a potential greater than 100% reduction in greenhouse gas emissions compared to gasoline. This significant greenhouse gas reduction is enabled by use of cellulosic co-products as a source of renewable energy. The DuPont biorefinery co-product is a material that can displace coal in facilities currently burning this fossil fuel.
Regional businesses and academic institutions have already indicated interest in exploring the potential use of the renewable co-products to replace portions of their coal fired operations.