(280b) Novel Analytical System for Exhaust Emissions Control Catalysts

Spatially-resolved gas composition measurements inside operating catalysts provide unique information for optimization of the exhaust emissions control catalytic systems and their applications, and in particular for the development and validation of the catalyst device models. Spatially-resolved capillary-inlet mass-spectrometer (Spaci-MS) has been developed jointly by Cummins and Oak Ridge National Lab to address this need. Due to the minimally disturbing sampling capillary size (160-350μm) and flow rates (nano-liters per minutes), as well as fast instrument response time, Spaci-MS proved very useful to the inherently transient catalytic systems used in the diesel exhaust emissions control.

One limitation of the conventional mass-spectrometry techniques is their inability to resolve isobaric species, for example CO and N₂, H₂S and ¹⁶O¹⁸O, etc. In this presentation we will share the results of our work introducing oxidation catalyst inside a 50μm i.d. capillary tube in a controlled fashion, to conduct in-situ chemical reactions to differentiate isobaric species typical for the diesel exhaust applications. Also, the initial results suggest that the developed analytical system can provide some unusual opportunities for quantitative studies of the behavior of the catalyst deposited in the capillary tube, potentially serving as a unique micro-reactor for kinetic studies.