Thermogravimetric mass spectrometric characterization of two energy crops, Arundo donax and Miscanthus sinensis

Two herbaceous plants, Arundo donax and Miscanthus sinensis with high biomass production potential, were studied by simultaneous thermogravimetry/mass spectrometry (TG/MS) in an inert argon atmosphere at a heating rate of 20 degrees C min(-1). The effect of particle size, the partial removal of the minerals by acid- and water-washing, and the effect of potassium carbonate as catalyst were studied. Experiments with covered sample pans were carried out to investigate the effect of secondary tar cracking on the charcoal production. TG/MS supplied intensity profiles of the low molecular weight volatile products as a function of time or temperature. Their comparison to the weight-loss rate curves (DTG) provided information of the details of the degradation mechanism. The amounts of various volatile pyrolysis products were estimated by the integrals of the corresponding mass spectrometric intensities. The factors influencing the char yield were discussed.