Research Project Summary Information
Energy-Efficient Extraction of Xylan from Willow(ST6738-1)
SUNY Research Foundation
Xylan, a component of wood, can be used to make high-value products. A current extraction process has been developed for maple chips, but needs to be adapted to the higher bark content and lower density of willow.
The goal was to develop a practical method to extract xylan from biomass wood chips for use as a bioproduct feedstock. Maximum extraction may conflict with maximum quality of residual chips, but the chips may also have improved accessibility to pulping chemicals. Properties of pulps were to be compared with control chips, as well as with fungally pretreated chips. Standard kraft and novel oxygen pulping were to be used to test the value of the residual chips. The dissolved organics were to be tested for fuel value and for use in a novel thermodepolymerization system. Xylan at $0.10/lb was targeted. The net increase in value of willow feedstock could range from $98-560/acre. A master’s thesis was written and sucessfully defended based on this work.
The combination of acetic acid results and main project results lead to a proposed application at International Paper at Ticonderoga. An ethanol and acetic acid production system could be based on the current wood furnish. The targeted removal of xylan for this system is just over 50%, which is achievable with little furfural production, with or without biopulping. Also, willow biomass is appropriate for CHP applications, and this extraction procedure (with follow on improvements) may eventually reduce the cost of the residual fuel, left over after biorefining, by 30 50%.
Hot water extractions, with and without fungal pretreatment, were completed. Fungal pretreatment allowed extraction of equal amounts of material at temperatures (in the range from 140 160 C) up to 10+ C higher than without pretreatment. This will allow lower energy costs or shorter extraction times (two hours were used in this study). Extracts and residual willow chips were analyzed, and the amount of lignin removed by the procedure was surprisingly high. Greater lignin removal from willow opens up the opportunity for an additional co product because this lignin is lower in sulfur and is likely to be more useful in commerce than conventional pulping lignins. The extract is predominantly xylose and xylan oligomers with a high acetic acid content (from the acetyl groups in wood). Acetic acid may also be a valuable coproduct (current price greater than $0.25 per pound) with a value per pound equal or greater than cellulose.
The highest recovery of xylan achieved in the extract was 60.5%. This was below the 75% target. The economic analysis was therefore not performed because the production of furfural (which is produced from xylose under acid and high temperature conditions) was not understood. Projected cost estimates based on the other successful components of the project, are now well below $0.10/pound of xylan, and the project results helped lead to an investigation of the potential for acetic acid production.
SUNY Research Foundation
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SUNY College of Environmental Science an
Indigenous/Renewable Energy Resources
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R&D - Environment & Energy Res