Modeling for proximate analysis and heating value of torrefied biomass with vibration spectroscopy Brian K. Via∗,a,b,c,, Sushil Adhikarib,c, Steve Taylorb,c a Forest Products Development Center, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849, USA b Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, USA c Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL 36849, USA Note: This is the Accepted Author Manuscript Version for the following Journal Publication Reference below. Via, B. K., Adhikari, S., & Taylor, S. (2013). Modeling for proximate analysis and heating value of torrefied biomass with vibration spectroscopy. Bioresource technology. 133: 1–8. ∗ Corresponding author at: Forest Products Development Center, School of Forestry and Wildlife Sciences, Auburn University, 520 Devall Drive, Auburn University, Alabama 36849 E-mail address:
[email protected] (B. Via), Telephone: 334-844-1088 and Fax: 334-844-1084 1 Abstract The goal of this study was to characterize the changes in biomass with torrefaction for near infrared reflectance (NIR) and attenuated total reflectance Fourier transform infrared (ATR- FTIR) spectroscopy for sweetgum, loblolly pine, and switchgrass. Calibration models were built for the prediction of proximate analysis after torrefaction. Two dimensional (2D) correlation spectroscopy between NIR and FTIR was found to precisely explain the depolymerization at key functional groups located within hemicellulose, cellulose, and lignin. This novel 2D technique also demonstrated the possibility of assigning key NIR wavenumbers based on mid IR spectra. Hemicellulose based wavenumbers were found to be most sensitive to torrefaction severity with complete degradation at 250-275oC. Lignin associated wavenumbers exhibited the least degradation to severity but was still detected with 2D correlation spectroscopy.