Trace metal release during wood pyrolysis

Abstract

The use of a differential thermal analyzer with an on-line inductively coupled plasma mass spectrometer allows continuous and near-synchronous analysis of mass loss and elemental release patterns during pyrolysis of biomass and other feedstock. Applied to a mixed-conifer softwood, the results show that the released elements can be divided into those that are dominantly released during decomposition (250–475°C) and those that are dominantly released at high temperature (900–1300°C), thus reflecting their different roles in the organic matrix. Production and analysis of a 950°C pyrolysis wood ash allows the bulk partition between flue gas (including entrained particles) and solid char to be evaluated, mass balance to be demonstrated, and a semi-quantitative calibration to be suggested. Our exploratory experiment demonstrates that the present approach can provide reliable insight and semi-quantitative modeling tools useful for elucidating the role and behavior of many elements during thermal treatment of biomass.