Feedstock of the future – lignocellulosic agricultural residues
Lignocellulose is the feedstock used for our sunliquid® process. Lignocellulose provides structural support for cell walls in biomass gained from forestry and farming. Its stable structure is made up of cellulose, hemicellulose and lignin, the exact composition varying according to the type of plant. Within a short time, we are able to adjust our sunliquid® process to the most varied types of feedstock, including cereal straw, corn stover, bagasse, or energy crops such as miscanthus and switchgrass. We have processed wheat-straw, corn stover and bagasse at our demonstration plant in Staubing showing good results. A number of other lignocellulosic feedstocks have been tested at pilot and lab scale.
Availability of lignocellulosic feedstock
The US, Asia and the European Union are leading producers of agricultural by-products, such as straw from rice, corn and cereal crops. Surplus straw offers an ideal feedstock for the manufacture of cellulosic ethanol, presenting no competition to the production of food or animal feed. Nor is any additional land use required to produce bioethanol based on these types of feedstock, as they are automatically created as a by-product during existing production of rice, maize and cereals.
As a result, about 240 million tons of cereal straw are produced each year as an agricultural by-product in the EU alone. Only a small part of this is currently utilized. Long term studies have shown that up to 60% could be taken of the field and are thus available for further uses. By processing this amount of straw, about 25% of the predicted EU demand for petrol could be replaced by cellulosic ethanol in 2020, solely out of surplus material. This means that cellulosic ethanol can play a key role along Europe´s path towards sustainable and climate-friendly road transport.
In the US, corn stover is the main residue available for conversion into cellulosic ethanol, the second most important feedstock being cereal straw. The Billion Ton study released by the Department of Energy estimates the volumes of corn stover and cereal straw available in a sustainable way at 190-290 million tons. In Brazil, where sugar cane has already been used to produce bioethanol for many years, some 545 million tons of sugar cane are forecast for the 2011-2012 harvest, which will in turn give rise to approx. 73 million tons of bagasse. Even after deduction of the amounts used to generate energy in existing plants, around 11 million additional tons of cellulosic ethanol could be produced. This is equivalent to about 50% of Brazil´s current ethanol production.
By combining advanced conversion technology and renewable resources, reallocating pasture for arable land and activating fallow farmland, it would seem possible to replace fossil fuel with cellulosic ethanol in the medium to long term.
- Cereal straw (wheat, barley ...)
- Corn stover
- Bagasse (from sugar cane)
- Rice straw