Patent ID: 6471926
Filing Date: 2002-10-29
Classification: B01J,C04B

Abstract:
A method for achieving catalytic selectivity for nitrogen oxides (NOx) reduction applications in flue gas streams such that the unwanted sulfur dioxide (SO2) to sulfur trioxide (SO3) reaction is minimized comprising:(a) preparing a thin aerogel catalytic monolith with internal surface area and flow through gas channels, said monolith being reinforced with pre-tensioned fibers; (b) placing said aerogel catalytic monolith in the flue gas stream such that the flow through gas channels permit the NOx,(SO2, and ammonia in the flue gas to fully access the internal surface area of the catalytic material; (c) causing said flue gas stream containing SO2, NOx, ammonia, and constituents typically occurring in flue gas to flow through the gas channels in the aerogel catalytic monolith; (d) selectively reacting said ammonia with the NOx on the catalyst surface inside the aerogel catalytic monolith gas channels while minimizing the amount of SO2 that is oxidized on the catalyst surface to Sulfur Trioxide (SO3); wherein the length of said gas channels is approximately five times less than the length necessary for fully developed laminar flow; the catalytic material in the said aerogel catalytic monolith consists of an aerogel comprised of a mixture with the following weight percent composition range, TiO2 70 to 90, WO3 5 to 20, V2O5 5 to 20, and ZrO2 0.5.