Application of Thermogravimetry for Determination of Carbon Content in Biomass Ash as an Indicator of the Efficiency of the Combustion Process

Abstract

The determination of the amount of residual carbon in biomass ash is important not only for the assessment of the efficiency of biomass fuel combustion but also as one of the criteria for the estimation of biomass ash potential use. In this paper carbon content in biomass ash was analysed by applying two methods: total organic carbon analysis (TOC) and thermogravimetric analysis (TGA) in an inert (N2) and oxidizing (O2) atmosphere. The amount of inorganic (carbonate) carbon can be directly calculated from the TGA curve and the obtained results are in a good agreement with the ones obtained using TOC analyser. On the other hand, the quantitative determination of organic and elemental carbon by TGA is not straight-forward since the temperature range of their oxidation overlaps with dehydration temperature of portlandite that is a constituent of biomass ash. It can be concluded that a basic version of the thermogravimetric analyzer can be used for the determination of inorganic carbon in ash samples, but for total organic carbon determination, it is recommended to use hyphenated techniques, for example, TGA-MS or TGA-FTIR that allows quantitation of evolved gases (CO2 and H2O).

Sustainable Hybrid Lime Mortars for Historic Building Conservation: Incorporating Wood Biomass Ash as a Low-Carbon Secondary Binder

“…The first predominant range of mass loss from 300 • C to 500 • C can be attributed, at least in part, to the decomposition of portlandite, which is the only one of the aforementioned minerals present in the NHL and WBA that is expected to dehydroxylate in this temperature range [68]. The available lime in NHL and WBA, i.e., the Ca(OH) 2 content, was determined based on mass loss in the 300-500 • C range, while the calcite content present in the samples was determined based on the mass loss in the second dominant range of 550-850 • C, which corresponds to CO 2 release from carbonates [68][69][70]. When comparing the DTG curves of WBAs and NHL, it is noticeable that the endothermic peaks in both regions are shifted to the left, i.e., the decomposition temperature is somewhat lower.…”