What is the best configuration of sampling capillary for Fast-SpaciMS in catalytic monoliths?

0566440 - ÚT 2023 eng A - Abstract
Kočí, P. - Hlavatý, Tomáš - Isoz, Martin - Deka, D. - Partridge, W.
What is the best configuration of sampling capillary for Fast-SpaciMS in catalytic monoliths?
[International Symposium on Modeling of Exhaust-Gas After-Treatment (MODEGAT VII) /7./. 11.09.2022-13.09.2022, Bad Herrenalb]
Institutional support: RVO:61388998
Keywords : CFD * openFOAM * catalytic filter * spaciMS
OECD category: Chemical process engineering

SpaciMS is an analytical technique based on mass spectrometry that provides spatially resolved measurements of transient species concentrations in catalytic monoliths by inserting a thin sampling capillary directly into one of the monolith channels. SpaciMS is often used to identify the reaction sequence and kinetics. In most cases, it is preferred to measure the concentration that is averaged over the channel cross-section and represents well the situation in a free channel. There exist two effects that may lead to measuring different concentration values. First, the capillary blocks certain part of the channel, slows down the flow and increases the residence time in the sampled channel, which results in a higher conversion of the exhaust gases in comparison to the unobstructed channels. This effect is more important for thicker capillaries but can be minimized by setting proper sampling rate that may compensate the increased resistance for the channel flow. The second issue may arise with very thin capillaries that sample local concentration, usually near the wall coated with the catalytic material as the capillary lies in the channel corner. Such a measurement may also provide higher than average conversion due to the radial concentration gradient in the channel.
Permanent Link: https://hdl.handle.net/11104/0338247