Monday, April 30, 2012
Napoleon Ballroom C-D, 3rd fl (Sheraton New Orleans)
Particles of softwood Douglas Fir (Pseudotsuga menziesii) were subjected to high pressure steam treatment of 200oC and 220oC for durations of 5 and 10 minutes. The high heating value of the steam treated pellets made from compacting particles increased from 18.84 to 20.09 MJ/kg. A kinetic model of polysaccharides depolymerization and pseudolignin formation is proposed. The pseudolignin model is formulated from a combination of the first order autohydrolysis of galactan depolymerization and the first order reaction of lignin solubilization and condensation in the acetic acid. An additional reaction pathway including the hydroxylmethylfurfural and lignin polymerization is introduced. The predicted residual galactan inside the solid residue after steam treatment had a reasonable fit to the experimental data. The predicted pseudolignin content showed an increasing trend with treatment temperatures.