Synthesis of Macro-Porous De-NOx Catalysts for Poly-Tetra-Fluoro-Ethylene Membrane Bag Filter.

Abstract

This study examined the effects of the porosity of catalytic bag-filter materials for applications to the SNCR (selective noncatalytic reduction)-SCR (selective catalytic reduction) hybrid process for highly treating nitrogen Oxides (NOx) in the exhaust gas of a combustion process. A V₂O5/TiO₂ catalyst was dispersed in a PTFE (poly-tetra-fluoro-ethylene) used as the catalytic bag-filter material to remove particulate matter and nitrogen oxides contained in the combustion exhaust gas. Macroporous alumina was added into a V₂O5/TiO₂-dispersed PTFE to improve the catalytic activity of V₂O5/TiO₂ dispersed in the PTFE material. In this study, the textural properties and denitrification performances of the V₂O5/TiO₂-dispersed PTFE materials were examined according to the addition of macro-porous alumina. When the denitrification catalyst was solely dispersed in the PTFE material, the catalyst inside the PTFE backbone had low gas-solid contact efficiency owing to the low porosity of the PTFE materials, resulting in low denitrification efficiency. On the other hand, the catalytic activity of V₂O5/TiO₂ dispersed inside the macro-porous PTFE material was significantly enhanced by adding macro-porous alumina into the PTFE matrix. The enhanced textural properties of the macro-porous PTFE material where V₂O5/TiO₂ was uniformly dispersed proved the facilitated diffusion of combustion exhaust gas into the PTFE material.