(519f) Deashing of Biomass By Deep Eutectic Solvent to Enhance Biomass Conversion Process | AIChE

(519f) Deashing of Biomass By Deep Eutectic Solvent to Enhance Biomass Conversion Process

Authors 

Islam, M. T. - Presenter, Florida Institute of Technology
Klinger, J., Idaho National Laboratory
Reza, T., Florida Institute of Technology
High ash biomass contains significant amount structural inorganics (monovalent, divalent and polyvalent metals) which affect the overall biomass quality as a biofuel. Hydrothermal carbonization (HTC) is a conventional and emerging thermochemical processing technology, where biomass is converted to low-ash, carbon-rich, energy-dense hydrochar. Yet, one of the shortcomings of HTC is that the polyvalent metals are entrapped in the complex structural matrix and almost impenetrable for leach out. Deep Eutectic Solvent (DES) is such a unique solvent that can leach structural inorganics out of biomass during pre-HTC treatment and augment in effective mass transfer during HTC. The purpose of this study is to pretreat raw biomass (e.g. Corn Stover High Ash Fraction, obtained from air classification technology) with Type-III DESs, i.e. choline chloride and urea (1:2 molar ratio), methyltriphenylphosphonium bromide and ethylene glycol (1:4 molar ratio) and observe the material, chemical and morphological change. The DESs, above their eutectic point, are mixed with the raw biomass and shaken for 30, 60, 90, and 120 mins at 155 °C in the oil bath. The treated biomasses are vacuum filtered with DI water and confirmed of no residual DES left by conductivity test. Finally, the biomasses are hydrothermally carbonized at three different temperatures (180 ºC, 220 ºC, 260 ºC), characterized through thermogravimetric analysis, scanning electron microscopy (SEM), SEM-energy dispersive x-ray (SEM-EDX) and induced coupled plasma-optical emission spectrometry (ICP-OES, and compared with untreated hydrochars of the same temperatures. It is hypothesized that the DES interacts with the polyvalent metals through softening the lignin-(hemi)-cellulose (LCC) complex as found in Van Soest fiber analysis method and aids in deashing (ash reduction). Overall, the pretreatment could notably improve the biomass fuel property and can be regarded as an important preprocessing step for higher biomass conversion process.