Oxy-fuel and air combustion performances and gas-to-ash products of aboveground and belowground biomass of Sedum alfredii Hance

Recovery of phosphorus from sewage sludge ash: Influence of incineration temperature on ash mineralogy and related phosphorus and heavy metal extraction

“…XRD analysis (see Figure 1.a) confirmed that no carbonates were present in the crystalline phase of the SSA samples obtained at incineration temperatures above 650 °C. Several authors found that the release of alkali and alkaline earth metals (specifically Ca, K, Mg and Na) from biomass fuels in general increases with increasing incineration temperature [34][35][36][37]. Yet, in this work, the Ca, K, Mg and Na concentration in the SSA remained relatively constant with increasing incineration temperature (5.45 -5.76% of DM, 1.94 -2.02% of DM, 1.24 -1.32% of DM and 0.34 -0.39% of DM for a temperature increase from 550 to 1100 °C, respectively).…”

“…Yet, in this work, the Ca, K, Mg and Na concentration in the SSA remained relatively constant with increasing incineration temperature (5.45 -5.76% of DM, 1.94 -2.02% of DM, 1.24 -1.32% of DM and 0.34 -0.39% of DM for a temperature increase from 550 to 1100 °C, respectively). This is related to the high concentration of Si in the SS and hence also in the SSA (18.79 -19.58% of DM), retaining Ca, K, Mg and Na in the silicate fraction [34][35][36][37]. XRD analysis (see Figure 1.d) indeed showed that these alkali and alkaline earth metals are bound in the silicate fraction as diopside (CaMgSi2O6), microcline (KAlSi3O8), muscovite (KAl3Si3O10(OH,F)2), plagioclase ((Na,Ca)(Si,Al)4O8) and smectite-related minerals (e.g., (Na,Ca)0.3(Al,Mg)2Si4O10(OH)2.xH2O), all having high boiling points.…”

“…Between 550 and 650 °C, there was a decrease in the amount of amorphous fraction, after which it remained more or less constant between 650 and 900 °C. At temperatures above 900 °C, the amount of amorphous fraction started to increase again since higher incineration temperatures imply more glassy SSA due to agglomeration caused by silicate melting [37,[48][49][50][51]. Unfortunately, the mineralogy of the heavy metals could not be detected by XRD analysis because of their low concentrations in the SSA samples [45,46].…”

Comparative Thermal Degradation Behaviors and Kinetic Mechanisms of Typical Hardwood and Softwood in Oxygenous Atmosphere

“…Three-dimensional diffusion E α and A estimates gained by the above two kinetic approaches are employed to compute the changes in enthalpy (∆H), Gibbs free energy (∆G), and entropy (∆S), expressed as [44]:…”

“…The values of the changes in enthalpy (∆H), Gibbs free energy (∆G), and entropy (∆S) of hardwood and softwood in region 1 were estimated from the thermogravimetric data at the heating rate of 15 K/min, as listed in Table 7. The difference between E and ∆H represents the potential energy barrier in the process of biomass combustion [44]. The smaller the potential energy barrier, the easier the reactants transform into products.…”