Drag-induced apparent mass gain in thermogravimetry

This paper shows how aerodynamic drag in thermogravimetric equipment may be corrected, and noise inherent in the data removed. Although it is entirely possible to correct drag-induced mass gain empirically, this publication is intended to allow the reader to understand the cause, correct for it, and remove noise appropriately. Apparent mass gain is described in terms of a generalised Stokes' formulation. A method is developed that enables the quantification of drag inside thermogravimetric equipment, which when combined with the Savitsky-Golay smoothing filter enables temperature-dependent apparent weight gain effects to be removed. It is necessary to account for this effect in proximate analysis and in the determination of kinetic parameters of thermal degradation. (c) 2007 Elsevier Ltd. All rights reserved.