USE OF THERMOMECHANICAL ANALYSIS TO QUANTIFY THE FLUX ADDITIONS NECESSARY FOR SLAG FLOW IN SLAGGING GASIFIERS FIRED WITH COAL

Coals with high ash fusibility temperatures are utilized in slagging g asifiers with the addition of a flux in order to lower ash melting tem peratures and slag viscosity. Recently, thermomechanical analysis (TMA ) has emerged as a technique that can characterize coal ash and slag b ehavior. The progressive shrinkage of heated coal ash samples mixed wi th calcium flux (CaO) has been measured using TMA. The resulting shrin kage has been correlated with the viscosity measured in a rotating bob viscometer for the same samples in order to quantify flux levels nece ssary for the viscosity required for coal fired slagging gasifiers (15 -25 Pa . s). For this viscosity range, shrinkage levels in the range o f 10-95% were obtained, indicating that the TMA technique has the pote ntial to quantify the necessary flux additions.