On the importance of the phase distribution and acidity of VOx-ZrO2-SO4-sepiolite catalysts for the NH3-SCR process in relation to biomass fueled power plants

A series of V2O5-ZrO2-SO42- - sepiolite mixtures were extruded, calcined and characterized. NH3-SCR activity was related to the phase distribution of the agglomerant and active VOX-ZrO2-SO42- phase, as well as the acidity of the composite material. Electrophoretic migration results showed that the addition of sepiolite to zirconia had effect on the quantity of zirconia present at the support’s surface, both strongly decreasing the molar fraction of zirconia at the surface, and altering the electrophoretic properties of the mixtures. Addition of extra ammonia sulfate eliminate both effects, and thus facilitate the production of a sepiolite-based conformed catalyst based on VOx-ZrO2-SO42-, which has been shown to be more resistant to the industrially implemented V2O5-WO3/TiO2 catalyst.