10.1021/ef4018114.s001 Paula Teixeira Paula Teixeira Helena Lopes Helena Lopes Ibrahim Gulyurtlu Ibrahim Gulyurtlu Nuno Lapa Nuno Lapa Pedro Abelha Pedro Abelha Slagging and Fouling during Coal and Biomass Cofiring: Chemical Equilibrium Model Applied to FBC American Chemical Society 2015 bed agglomeration phenomena Biomass Cofiring bottom zone biomas chemical composition elutriation effects occurrence chemical fractionation silica sand particles wood pellets combustion process straw pellets liquids salts FBCA Chemical Equilibrium Model Applied fluidized bed monocombustion nonreactive fraction cocombustion effect 2015-12-17 00:14:43 Journal contribution https://acs.figshare.com/articles/journal_contribution/Slagging_and_Fouling_during_Coal_and_Biomass_Cofiring_Chemical_Equilibrium_Model_Applied_to_FBC/2027673 A thermodynamic model was applied to foresee the occurrence of fouling, slagging, and bed agglomeration phenomena during fluidized bed monocombustion of three different types of biomass, namely straw pellets, olive cake, and wood pellets. The cocombustion effect in reducing the occurrence of deposits and agglomerates of blends of 5, 15, and 25% (wt.) biomass with coal was also assessed. Chemical fractionation was applied to evaluate the reactive and nonreactive fraction of elements in the fuels, which was used to estimate their partition between the freeboard and bottom zone of the boiler. Qualitative and semiquantitative analytical techniques, namely, X-ray diffraction and scanning electronic microscopy – energy dispersive spectroscopy were used to compare the results from the simulation with the mineralogical and morphological composition of ash and deposits formed during combustion. The thermodynamic modeling revealed to be a powerful tool in foreseeing the formation of melt and liquids salts, depending on the temperature and chemical composition of fuels. The main discrepancies observed between the experimental and simulated data were due to particularities of the combustion process, which are not incorporated in the software, namely, kinetic limitations of the reactions, possible occurrence of secondary reactions in the ashes, and elutriation effects of ash and silica sand particles.