Analysis of Microelement (Mn, Fe, Cu, Zn) Content in Ash of Briquettes from Different Biomasses

Abstract

Mineralna supstanca biomase predstavlja količine metala prisutne u obliku neorganskih i organskih soli, kompleksnih jedinjenja ili jona tokom vegetacionog perioda. Određivanje sadržaja pepela, odnosno mineralne supstance dobijene sagorevanjem biomase, ključni je parametar za procenu kvaliteta i klase biogoriva. Poznavanje kvalitativnog i kvantitativnog sastava minerala značajno je zbog uticaja oksida u pepelu na njegove fizičke karakteristike i temperature topljenja. U ovom radu sprovedena je kvalitativna analiza mikroelemenata (Mn, Fe, Cu, Zn) u pepelu dobijenom sagorevanjem briketa pripremljenih od duvanskih i sojinih stabljika, pšenične slame, ostataka glavica suncokreta, oklasaka kukuruza i piljevine drveta bukve, prema standardu EN 14961-2. Najniži sadržaj Mn (207 mg/kg) utvrđen je u uzorku duvanske stabljike, dok je najviši sadržaj Mn zabeležen u oklascima kukuruza (1447 mg/kg). Sadržaj Fe najniži je u piljevini bukve (2,78 mg/kg), a najviši u sojinoj slami (18,35 mg/kg). U ostatcima glavica suncokreta registrovane su najniže vrednosti Cu (44,58 mg/kg) i Zn (74,40 mg/kg), dok su piljevina bukve imala najviše vrednosti (148,7 mg/kg za Cu i 335,8 mg/kg za Zn). Analiza je pokazala da uzorci različite biomase značajno variraju u sadržaju mikroelemenata, što je od važnosti za primenu biomase u proizvodnji biogoriva i predviđanje ponašanja pepela tokom sagorevanja.The mineral substance of biomass represents the amounts of metals present in the form of inorganic and organic salts, complex compounds, or ions during the vegetation period. Determination of ash content, i.e., the mineral substance obtained by biomass combustion, is a key parameter for assessing the quality and class of biofuel. Knowledge of the qualitative and quantitative composition of minerals is important due to the influence of oxides in ash on its physical properties and melting temperatures. In this study, a qualitative analysis of microelements (Mn, Fe, Cu, Zn) was conducted in ash obtained from the combustion of briquettes prepared from tobacco and soybean stems, wheat straw, sunflower head residues, maize cobs, and beech wood sawdust was carried out, according to the EN 14961- 2 standard. The lowest Mn content (207 mg/kg) was found in the tobacco stem sample, while the highest Mn content was recorded in maize cobs (1447 mg/kg). The lowest Fe content was found in beech sawdust (2.78 mg/kg), and the highest in soybean straw (18.35 mg/kg). The lowest Cu (44.58 mg/kg) and Zn (74.40 mg/kg) contents were recorded in sunflower head residues, while beech sawdust had the highest values (148.7 mg/kg for Cu and 335.8 mg/kg for Zn). The analysis showed that different biomass samples significantly vary in microelement content, which is important for biomass application in biofuel production and predicting ash behavior during combustion