Filtration of chromium from flue gas in furnace stacks

Abstract

Chromium particulate emissions in flue gas can be reduced or minimized by incorporating a thin layer bed of a catalyst within the flue gas flow path of a furnace, boiler, or other furnace environment that includes Cr-containing surfaces. The thin layer bed of catalyst can correspond to, for example, a honeycomb monolith with catalyst supported on the monolith surface, so as to provide a high contact area while forcing all of the flue gas to pass through the catalyst bed. The honeycomb monolith structure and the depth of the bed can be selected to provide a reduced or minimized pressure drop across the catalyst bed, such as a pressure drop of 0.25 kPa (1.0 inches of water) or less. Exposing the Cr-containing flue gas to the thin layer catalyst bed can result in a treated flue gas with a lower content of Cr.