Cross-flow, filter-sorbent-catalyst for particulate, SO2 and NOx control. Final report

摘要

This report describes work performed on a new concept for integrated pollutant control: An active filter comprised of layered, gas permeable membranes that act as a particle filter, an SO(sub 2) sorbent, and a NO(sub x), reduction catalyst. The focus of the research program documented in this final report is the development of the sorbent/catalyst materials that are the basis of such an emission control system. The device investigated in this program will simultaneously remove particulates, SO(sub 2) and NO(sub x), from combustion exhaust gases. Sulfur dioxide capture and nitrogen oxide reduction are achieved with a reg le, mixed-metal oxide sorbent-catalyst. The device is a filter with layered walls: A small-pore layer is a barrier to particles, and a macroporus active layer is a SO(sub 2) sorbent and a catalyst for the selective catalytic reduction of NO(sub x). The small-pore layer could be an inert ceramic that provides structural strength to the unit and protects the active (sorbent-catalyst) material from abrasion or contamination from fly ash particles. We have found that 95--100% removal efficiency of SO(sub 2) and 60--90% removal of NO(sub x), is achievable with the use of mixed-metal oxide sorbent-catalysts in the device. The ceramic filters are barriers to particles and typically have removal efficiencies of 99.9%.