425172 Effect of Fast Pyrolysis Conditions on Structural Transformation and Reactivity of Herbaceous Biomasses at High Temperatures

Wednesday, November 11, 2015: 8:30 AM
250D (Salt Palace Convention Center)
Anna Trubetskaya, Chemical Engineering Department, Danish Technical University, Lyngby, Denmark, Anker D. Jensen, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark, Peter Arendt Jensen, CHEC, Department of Chemical & Biochemical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark, Peter Glarborg, Department of Chemical and Biochemical Engineering, Denmark Technical University, Lyngby, Denmark, Hartmut Spliethoff, Institute for Energy Systems, Technical University Munich, Garching, Germany, Markus Steibel, TUM Muenchen and Flemming Hofmann Larsen, Department of Food Science, University of Copenhagen, Copenhagen, Denmark

Fast pyrolysis of wheat straw and rice husks was carried out in an entrained-flow reactor (EFR) and compared with the results from the wire-mesh reactor (WMR) in terms of the char yield at high-temperatures (1000-1500°C) to study the effect of heating rate, final temperature, ash content and particle size on the char yield. X-ray diffractometry (XRD), N-adsorption (BET), scanning electron microscopy (SEM), particle size analysis (CAMSIZER XT), nuclear magnetic resonance spectroscopy (29Si NMR; 13C NMR) and electron spinning resonance spectroscopy (ESR) were conducted to investigate the effect of organic and inorganic matter on the char structural transformations. The results indicate no influence of the free radicals on char reactivity and burnout. The formation of free radicals in fast pyrolysis is related to the differences in the ash composition, namely presence of K+ ions in the wheat straw and formation silanol silicons at higher temperatures. The microscopy and 2D imaging analysis show that the differences in ash and extractives of rice husks and wheat straw affect significantly the char particle size and shape. The char yields of rice husks in the EFR, correspond to the WMR results, emphasizing its excellent properties as an ash tracer for the more precise recovery of elemental mass balances in pyrolysis.

Extended Abstract: File Uploaded
See more of this Session: Thermochemical Conversion of Biomass I
See more of this Group/Topical: 2015 International Congress on Energy