Control of trace elements in a gasifier hot gas filter: A comparison with predictions from a thermodynamic equilibrium model

A thermodynamic equilibrium model has been used to make predictions of the speciation of trace elements in the fuel gas from a gasifier. In contrast w ith previous studies of this nature, experimental data was available to ena ble the validity of these predictions to be tested. Although Be, Co, Cu, V, and Zn had been detected in the fines collected by the hot gas filter, no significant amount of these elements was predicted to be in the form of gas eous-phase species, and this was confirmed by the experimental data. The el ements As, B, Cd, Pb, Sb, and Sn were all predicted to form a larger amount of gaseous species than measured experimentally. Some of these differences may be attributable to the current unavailability of thermodynamic data fo r the more complex minerals and adsorbed species that may be formed. Refine ment of the predictions for As and B by inclusion of specific minor/trace e lement interactions with Ni and Ca, respectively, gave a better agreement w ith the experimental data. Thermodynamic equilibrium modeling is a useful t ool for providing a qualitative understanding of trace element behavior, an d for formulating strategies for their control.