An Analysis Of The Impact Of Storage Temperature, Moisture Content & Duration Upon The Chemical Components & Bioprocessing Of Lignocellulosic Biomass

<p>The successful utilization of lignocellulosic biomass as a feedstock for fuels and chemicals necessitates storage for 2-6 months. It is correspondingly important to understand the impact of storage parameters - moisture concentration, temperature and duration - on biomass quality.</p> <p>As aerobic storage is the most viable large-scale solution, aerobic storage experiments were carried out with three projected bioenergy feedstocks - sweet sorghum (Sorghum bicolor) bagasse, corn (Zea mays) stover and switchgrass (Panicum virgatum). Stored samples of each were examined for dry matter loss and composition change to develop a material balance around carbohydrates and lignin.</p> <p>A mean dry matter loss of 24% was observed at 8 weeks in sweet sorghum stored at high moisture content (26% w/w). Soluble sugars predominated the dry matter loss in high-moisture sorghum, causing an increase in the mass fraction of lignin in the biomass. In comparison, low-moisture (12% w/w) samples showed negligible loss. High-moisture sorghum dried from 26% to 20% in 8 weeks, and further to 8% in 24 weeks.</p> <p>To control moisture loss in subsequent experiments, switchgrass and corn stover were wetted to specific water activities (aw) and stored under equivalent controlled humidities.</p> <p>Switchgrass stored at water activities of 0.65-0.85 showed no dry matter loss, irrespective of storage temperature or duration. Switchgrass stored at a water activity of 0.99 (~33% w/w moisture) showed significant dry matter loss at temperatures of 20 and 35 °C, although substantial sample-to-sample variation was observed at 20 °C compared to 35 °C. At 8 and 16 weeks, switchgrass stored at 0.99 aw and 35 °C lost 7% dry matter on average. Corn stover was stored under similar conditions (35 °C, 0.97 aw) for 8 weeks. The stored samples showed 10% dry matter loss on average. The dry matter losses predominantly consisted of cellulose and hemicellulose, resulting in the mass fraction of lignin increasing in switchgrass from 26.6% to 27.0% in 8 weeks and 28.8% in 16 weeks, and in stover from 23% to 25% in 8 weeks.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Agricultural and Biological Engineering

Year

2013

Author dc:creator

• Athmanathan, Arun

Contributors dc:contributor

• Nathan S. Mosier
• Michael R. Ladisch
• Dennis R. Buckmaster
• Keith D. Johnson

• cellulose digestibility
• corn stover
• dry matter
• lignin
• liquid hot-water pretreatment
• switchgrass
• Biochemistry
• Chemical Engineering
• Oil, Gas, and Energy

Repository record dc:identifier

https://docs.lib.purdue.edu/open_access_dissertations/202

OAI identifier oai:identifier

oai:docs.lib.purdue.edu:open_access_dissertations-1012