Gunnar Eriksson

Fuel Characterization of Pellet Chips

Small hardwood chips, known as pellet chips, were characterized and combusted in two different pellet burners, installed in a residential boiler specially designed for pellet combustion. The averag ...

A generalized approach to the flood-knapp structure based model for binary liquid silicates: Application and update for the PbO-SiO2 System

The nonideal activity of a metal oxide in a molten binary silicate system is described by treating the liquid as an ideal solution and by considering the formation of a few complexes. Application of this approach to the binary system PbO-SiO2 shows that the experimentally determined activity of PbO(l) can be modeled by considering the lead silicate melt as an ideal solution of Pb2+ and O2−,SiO44−, Si2O76−, Si12O3726−, and Si4O104−. The calculated Gibbs free energy values for the formation of the anionic complexes from O2− and SiO44− are: ΔGℴ(Si2O76−)/J · mol−1 = 38977 − 30.909(T/K); ΔGℴ(Si12O3726−)/J · mol−1 = 200158 − 121.813(T/K); Δℴ(Si4O104−)/J · mol−1 = 104627 − 28.094(T/K). Values of Gibbs free energy of formation of the solid phases PbO, Pb4Si06, Pb2SiO4, PbSiO3, and SiO2 which, together with the melt model data, give the best fit to experimental phase relations in the system PbO-SiO2 were calculated. These values are all in good agreement with literature data.

A solid state emf study of the pyrrhotite-magnetite equilibrium in the temperature interval 850 to 1275 K

The equilibrium 3/(1 −x)Fe1−xS(s) + (5 − 2x)/(1 −x)O2(g) Fe3O4(s) + 3/(1 −x)SO2(g) was studied in the temperature interval 850 to 1275 K by measuring oxygen potentials in a galvanic cell containing calcia stabilized zirconia as solid electrolyte. The SO2 activity was controlled by equilibrating the solid phases pyrrhotite and magnetite with a continuously flowing SO2-Ar gas mixture of known composition. Formation of S2 gas was taken into account and a recently published thermodynamic model for the pyrrhotite phase4 was used to derive the Gibbs energy change for the pyrrhotite-magnetite equilibrium and for the formation of Fe1−xS as a function of the variables temperature and pyrrhotite composition.