New approach for proximate analysis by thermogravimetry using CO2 atmosphere: Validation and application to different biomasses

Abstract

This study investigates the most appropriate conditions to perform the proximate analysis (moisture, volatile matter, fixed carbon, and ash) of biomasses by thermogravimetry, focusing on providing better distinction for quantification of volatile and fixed carbon components. It was found, using a series of thermogravimetric methodologies, that heating rate and particle size are important factors to be taken into account, whereas temperature and carrier gas (type and flow rate) are critical to enable the proper quantification of volatiles and fixed carbon. In this case, the best condition was achieved by applying 600 °C and CO2 as carrier gas (instead of N2). It is the highlight of the proposal method regarding the conditions often applied for this purpose. Furthermore, this method has proved to be advantageous in three important aspects: A single measurement is enough for quantification of all properties, it can be performed in a short time (1 h 27 min) in comparison with methods performed in a muffle furnace, and it can be applied for different kinds of biomasses, from lignocellulosic to residues. The procedure of validation demonstrated the low uncertainty of the data obtained by this method and the low propagation of uncertainty when they were applied for the prediction of the high heating value of the related biomasses, which supports its applicability as an alternative to biomass characterization.